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Department of Natural Resources MARYLAND GEOLOGICAL SURVEY Emery T. Cleaves, Director COASTAL AND ESTUARINE GEOLOGY FILE REPORT NO. 94-2 The surficial sediments of Assawoman Bay and Isle of 'Alight Bay in Maryfand: physical and chemical characteristics by Darlene V. Wells, Robert D. Conkwright, James M. Hill, and M. June Park z > -JU 32 Submitted to U.S.Department of the Interior Minerals Management Service Continental Ma-rgins Program and Bureau of Economic Geology The Universitv of Texas at Austin in fulfillment of Contract 414-35-0001-30643 QE 121 .S87 June,1994 1994 COMMISSION OF THE MARYLAND GEOLOGICAL SURVEY M. GORDON WOLMAN, CHAIRMAN JOHN E. CAREY F. PIERCE LINAWEAVER THOMAS 0. NUTTLE ROBERT W. RIDKY CONTENTS EXECUTIVE SUMMARY ............................................. I INTRODUCTION ................................................... 4 PREVIOUS STUDIES ................................................ 5 STUDY AREA ...................................................... 6 Geologic Setting ........................................ ....... 6 Physical Characteristics .......................................... 9 METHODS ...................................................... 13 Surficial Sample Collection ...... : ............................... 13 Laboratory Analyses ............................................ 13 Textural Analyses ......................................... 13 Chemical Analyses ........................................ 15 Nitrogen, Carbon, and Sulfur Analyses ..................... 15 Metal Analyses ..................................... 16 Data Reduction .......................................... 17 RESULTS AND DISCUSSION ........................................ 18 Sediment Texture ............................................. 18 Water Content ................................................ 24 Geochemistry ............................................ I .... 25 Carbon ................................................ 25 Nitrogen .............................................. 26 Sulfur ................................... 28 Metals ................................................. 30 Enrichment Factors ................................... 31 Variation from Historical Norms ......................... 32 Distribution of Variation Levels ......................... 35 CONCLUSIONS .................................................. 38 ACKNOWLEDGEMENTS ........................................... 40 REFERENCES CITED ............................................. 41 APPENDIX I Location Data and Field Descriptions of Sediment Samples ................. 47 APPENDIX II Textural and Geochernical Data for Sediment Samples .................... 69 iii FIGURES Figure 1. A) Generalized geologic map of central Delmarva Peninsula ............ 7 B) Cross-section showing stratigraphic relationship of formations (from Owens and Denny, 1979) ..................................... 8 Figure 2. Study area .............................................. 10 Figure 3. Bathymetry of Isle of Wight and Assawoman Bays based on surficial sample depths ..................................... 12 Figure 4. Surficial sample locations .................................... 14 Figure 5. Distribution of sediment type based on Shepard's (1954) classification ............................................. 19 Figure 6. Location of borings collected in 1962 by the U.S. Army Corps of Engineers ............................................ 21 Figure 7. Thickness of the sand sediments based the 1962 borings ............. 22 Figure 8. Bathymetric changes since 1962 at selected areas in Isle of Wight and Assawoman Bays ................................. 23 Figure 9. Distribution of total carbon content in surficial sediments for Isle of Wight and Assawoman Bays ............................... 27 Figure 10. Distribution of total sulfur content in surficial sediments .............. 29 Figure 11. Distribution of sigma levels for Zn variation from background levels in surficial sediments .................................. 36 Figure 12. Distribution of sigma levels for Cu variation from background levels in surficial sediments .................................. 37 iv TABLES Table 1. Morphometnic data for Isle of Wight and Assawoman Bays ............. 9 Table II. Results of nitrogen, carbon, and sulfur analyses of NTST-SRM 41646 (Estuarine Sediment) material compared to the certified or known values ............................................ 16 Table III. Results of the metal analyses of reference materials compared to the certified values ................. ....................... 17 Table IV. Summary of sediment type and areal extent for each classification mapped in Isle of Wight Bay and Assawoman Bay ........ 18 Table V. Correlation matrix for nitrogen, carbon, sulfur contents and sediment textural data based on all surficial sediment samples ......... 24 Table V1. Summary of water content, percent nitrogen, carbon and sulfur for each sediment type ...................................... 25 I Tab] e VII. Correlation matrix for trace metal concentrations and sediment textural data based on all surficial sediment samples ................. 31 Table VIR. Least squares coefficients for metal data ......................... 33 Table IX. Mean and standard deviation (cy) of variation values calculated from metal concentrations for sediments below 30 cm in the sediment column ....... 34 Table X. Coordinates (latitude and longitude) for surficial sediment sample lo' cations ............................................... 49 Table XI. Field descriptions for surficial sediment samples collected in Isle of Wight and Assawoman Bays ................................ 56 Table XII. Textural data for surficial sediment samples ....................... 71 Table XIII. Chemical data for surficial sediment samples ...................... 79 Table XIV. Enrichment factors, relative to average continental crust (Taylor, 1964), for metals analyzed n surficial sediments .................... 86 Table XV. Variation values for metal concentrations relative to predicted background (or historical) levels ............................... 93 v EQUATIONS Equation 1. Determination of water content as percent wet weight ............................................ 13 Equation 2. Calculation of the enrichment factor for a particular metal in sediment samples ................................ 32 Equation 3. Calculation of background metal concentration using grain size composition of the sediment ..................... 33 Equation 4. Determination of variation of measured metal concentrations relative to background metal concentration ....................................... 34 vi The surficial sediments of Assawoman Bay and Isle of Wight Bay in Maryland: physical and chemical characteristics by Darlene V. Wells, Robert D. Conkwright, June Park, and James Hill EXECUTIVE SUMMARY The Maryland Geological Survey conducted a two year investigation of the shallow geological framework and near surface geochernical character of the sediments of Assawoman and Isle of Wight Bays located along Maryland's Atlantic coast. This report presents the results of the second year study which focused on the physical and chemical characteristics of the surficial sediments of Assawoman and Isle of Wight Bays. The objectives of the second year study were: 1) To map the chemical and sedimentological characteristics of the surficial sediments; 2) To delineate the vertical stratigraphic sequence of Assawoman and Isle of Wight Bays. The study was funded through the Minerals Management Service (MMS)/University of Texas cooperative studies relating to continental margin. In order to accomplish these objectives, 172 surficial sediment samples were collected in Isle of Wight and Assawoman Bays as well as the lower tidal reaches of the major tributaries. The sediments were analyzed for water content, textural properties, total nitrogen, carbon and sulfur contents, and for six metals: Cr, Cu, Fe, Mn, Ni, and Zn. Results from these analyses were used to map the distribution of sediment type, nitrogen, carbon and sulfur contents and relative enrichment of the six metals in the surficial sediments. Seismic data collected during the previous year's study (Wells and others, 1994) along with data from a series of bonings collected by the Army Corps of Engineers were used to estimate thicknesses of the SAND, SILT and CLAY components in the two coastal bays. Based on the textural analyses of 171 surficial sediment samples, the average textural composition of the bay bottom sediments is 54% SAND, 28% SILT and 18% CLAY. The SAND to MUD ( SAND + CLAY components) ratio is nearly 1:1. SAND sediments (i.e. SAND > 75%), which cover approximately 44% of the bottom of the two bays, are found primarily along the eastern side of the bays. The SANDS vary in thickness from several cm to more than 8 meters, gradually thinning toward the west. CLAYEY SILTS, which cover approximately 14% of the study area, are found in the tributaries and in isolated pockets associated with marshy shorelines. SILTY CLAYS are restricted to upstream areas of the tributaries. SILTY SAND, SANDY SILT and SAND-SILT-CLAY are found in isolated pockets along marshy shorelines and along the boundaries between SAND and CLAYEY SILTS. Based on seismic data collected during the previous year study, the CLAYEY SILT deposits are estimated to be up to 5 meters thick in area east of the mouth of St. Martin River (due south of Isle of Wight Bay). This area corresponds to the thalweg of the St. Martin paleochannel. I Water content is strongly associated with the CLAY component of the sediment as reflected by the high correlation coefficient between percent water and CLAY content (r = 0.95). Water contents of SAND sediments average 21.6% while SILTY CLAY sediments have the highest water contents ( maximum value = 79%). Total carbon contents measured in the surficial sediments range from 0 to 9.86% with a mean value of 2.08%. Correlation analysis reveals strong associations between carbon content and % water (r = 0.89), and carbon content and CLAY (r = 0.88), indicating that carbon content is associated with the fine grained fraction. In general, the carbon content distribution closely follows the sediment distribution. The highest carbon values (>7%) were obtained from SILTY CLAY sediments collected in the upstream areas of Roy and Greys Creek and St. Martin river. Nitrogen contents in surficial sediments range from 0 to 0.59%, and average 0.16%. The highest nitrogen contents are associated with SILTY CLAYS found in upstream areas of the tributaries (St. Martin River, Greys Creek and Roy Creek). Nitrogen content of the sediments is strongly associated with carbon content (r = 0.915) reflecting the fact that nitrogen comes primarily from organic geopolymers found in the sediment. N/C va lues are generally low ( mean = 0.065) for sediments in the tributaries and along the marsh island areas between Greys Creek and Roy Creek, suggesting that nitrogen in sediments comes primarily from terrestrial organic material, probably as cellulose plant tissue. N/C values are higher, averaging 0.177, for the sediments collected in the central portions of Isle of Wight and Assawoman Bays. In these areas plankton is most likely the primary source of nitrogen in sediments. Total sulfur contents of the surficial sediments of the coastal bays range from 0 to 3.16% about a mean of 0.63%. Distribution pattern for sulfur contents are similar to those for nitrogen and carbon. Sulfur contents is greatly influenced by sediment texture. Correlation analyses show a strong association between sulfur and CLAY content (r = 0.91) and water content (r = 0.88). SILTY CLAYS collected in the tributaries yielded the highest sulfur contents, ranging from 1.41 to 3.16%. The ratio of carbon to sulfur (C/S) averages 3.56 � 1.32 for all samples. This value is much higher than the C/S ratio of 2.8 (� 1.5) for modem marine sediments reported by Berner and Raiswell (1984). The higher C/S values may reflect the origin and nature of the carbon contained in the sediments. A significant portion of the total carbon measured in many of the coastal bay sediments may be non-reactive carbon, perhaps in the form of plant material or inorganic carbon secretions in worm tubes. Correlations between metal contents and carbon, nitrogen, and sulfur contents are moderate to strong (r > 0.7). The highest correlations are between Fe and Cr (r = 0.984), Fe and Mn (r = 0.956) and Cr and Zn (r = 0.953). There area also high correlations between CLAY content and Cr, Fe, and Ni, and between water content and all six metals. These metals typically are associated with clay minerals as they are either components of the mineral lattice structure or absorbed onto clay surfaces. Because of the strong relationship between metal content and grain size, several techniques were used to normalize the metal data so the comparisons could be made between the different sediment types. One technique correlated metal content with the grain size composition. Metal concentrations in sediments below 30 cm in the sediment column were interpreted to represent 2 the historical norms for the coastal bays. These deeper sediments were used to obtain the relationship between grain size and metal contents to determine background metal concentrations. Background levels were calculated for all surficial samples based on grain size, and compared to the measured metal levels. Variation from background levels were then mapped. Variation levels for Cr, Fe, and Mn are not significant for most areas within the two bays; i.e., variation level values fall within the normal dispersion of background level values. On the other hand, variation levels for Cu and Zn indicate that the surficial sediments contain twice the amount of Cu and Zn than background levels (historical levels). Variation levels for Zn and Cu were mapped revealing distribution patterns that reflect anthropogenic influences within the two bays. High variation levels of both Cu and Zn are seen in the St. Martin River and in isolated pockets adjacent to developments and marinas. The developed shorelines contain dead-end canals and narrow boat slips, and thus by design, have poor water circulation, which contribute to the accumulation of these metals. Likewise, the St. Martin River acts as a sink for these metals as well as other pollutants, due in part, to the fine grained nature of the sediments. The variation levels for metals also reflect the relatively high pollutant input into the St. Martin River compared to other tributaries. 3 INTRODUCTION The Maryland coastal bay system consists of four bays: Assawoman Bay, Isle of Wight Bay, Sinepuxent Bay and Chincoteague Bay. These coastal bays are considered very valuable resources not only from a geological viewpoint, but from an environmental perspective. During the last two decades, development pressures along the shoreline around the bays have raised concerns about the "health" of the bays. Yet, there is a paucity of environmental data available to adequately assess and monitor the bays. Little is understood about the hydrodynamics and sedimentation processes. An understanding of the hydrodynamics of the bays is critical in dealing with dredging and disposal of polluted sediments. Because the bays are very shallow, bottom sediments are often resuspended, mixing with the overlying water column. Therefore, the bottom sediments play an important role in bay water quality. Sedimentological studies are important to the understanding of the relationship between bottom sediments and bay hydrodynamics as well as to the general health of the bays. During the past seven years of the Mineral Management Service-Association of American State Geologists (MMS/AASG) Continental Margins Program, the Maryland Geological Survey has mapped the surficial sediments and defined the shallow geological framework of the inner continental shelf of Maryland (Kerhin and Williams, 1987; Toscano and others, 1989). The area of study had been limited to the inner continental shelf of Maryland, and did not include the adjacent coastal bay systems. These coastal bays mark the leading edge boundary of the present transgression and overlie sedimentary sequences that link the onshore to offshore stratigraphy. Therefore, studies of the geologic framework of these bays would contribute to the understanding of the relationship between offshore and onshore stratigraphy and the history of the holocene transgression. For the eighth year of the MMS/AASG Continental Margins Program, the Maryland Geological Survey initiated a preliminary investigation of the shallow geological framework and near surface geochemical character of the sediments of Assawoman and Isle of Wight Bays located along Maryland's Atlantic coast. The purpose of this study was two-fold: 1) The information from this study would "fill in" some of the gaps in reconstructing the shallow stratigraphy and Quaternary history of Maryland's inner continental shelf. 2) The study would provide some preliminary base-line sedimentological and chemical data for future studies of these back-bay areas. The eighth year study was design as a reconnaissance investigation of the shallow geology of the two bays. Due to funding and time constraints, tasks were kept simple with seismic profiling being the primary tool of study. In addition to seismic profiling, a series of shallow sediment cores were collected along various transect with the two bays. Analyses of these sediment cores provided important geochernical behavior and history of the shallow sediment column in the bays (Wells and others, 1994). For the ninth year of the MMS/AASG Continental Margins Program, the Maryland Geological Survey continued the investigation of the geological framework of Assawoman and Isle of Wight Bays with the emphasis on the physical and chemical characteristics of the surficial 4 sediments. The objectives of the continuation of the Coastal Bays study were: 1) To map the chemical and sedimentological characteristics of the surficial sediments; 2) To delineate the vertical stratigraphic sequence of Assawoman and Isle of Wight Bays; Presented in this report are the results and preliminary interpretation of the data from the continuation of the Isle of Wight and Assawoman Bays Study. Results include the textural and chernical data from analyses of 171 surficial sediment samples collected in the two bays. PREVIOUS STUDIES Early studies focused primarily on water quality monitoring in the bays (Sieling 1958, 1959, 1960; Cerco and others, 1978; Allison 1975; and Fang and others, 1977). Water column studies conducted by Allison (1975) measured pH, salinity, water temperature, dissolved oxygen (DO), nutrients, chlorophyll-a, total iron, heavy metal and pesticide concentrations, turbidity, and fecal coliform bacteria. At twelve (12) sites within Isle of Wight and Assawoman Bays, Allison analyzed bottom sediments for six metals: Cu, Cr, Pb, Zn, Cd, and Hg. Although Allison concluded that the metals concentrations in the sediments were not significantly high, he did not elaborate on any relationship between sediment and water quality data. Several studies examined the physical character of sediments from Chincoteague Bay (Bartberger and Biggs, 1970; Bartberger, 1976). These studies involved the analyses of 150 Chincoteague Bay sediments for grain size characteristics in order to determine the origin, distribution, and rates of accumulation of sediments in Chincoteague Bay. Results showed that the sandy sediments were found on the eastern margins of the Chincoteague Bay. Fine-grained sediments were located in the deeper areas and along the western shore areas. The primary source of sand was from Assateague Island in the form of overwash, aeolian transport, and sediment run-off. By comparison, sediment input from streams was minor. Based on estimated volumes of annual sediment input into Chincoteague Bay, the average sedimentation rate was calculated to be 0.3 mm per year. Folger (1972) compiled existing data on the texture and composition of bottom sediments from 45 estuaries, lagoons, bays, and deltas of the United States. Seventeen of the study areas were on the Atlantic coast, but did not include any embayments between Chesapeake Bay and New York Harbor. Sediment characteristics examined by Folger included appearance, texture, mineral composition, and organic content. Folger correlated sediment characteristics with geologic , bathymetric, and hydrologic characteristics of the specific study basins. Folger concluded that sediment textures and distribution patterns are controlled by sediment supply and tidal range. More recently, an assessment of Maryland's coastal bay aquatic ecosystem and terrestrial pollutant loadings into the bays was completed (UM and CESI, 1993). The assessment, based on existing information, examined data for trends in the overall quality of the bays ecosystem. Objectives of the study were to identify water quality problems and to develop strategies for the 5 effective management of the bay system. The study identified the upper bays (Assawoman and Isle of Wight bays), and particularly the St. Martin River, as areas exhibiting serious water quality problems as a result of several factors including poor flushing, development along the shorelines, and high nutrient loadings. Estimates of nutrient loading rates for total nitrogen, total phosphorous, total suspended solids, zinc, lead and biochemical oxygen demand were calculated to be very high for Turville/Herring Creek and St. Martin River compared to those observed for selected portions of the Chesapeake Bay and other coastal bays. However, the study pointed out that there is a general lack of information regarding the toxic contamination in the upper bays and recommended developing a baseline for priority pollutants in sediments and biota.. STUDY AREA GEOLOGIC SETTING The study area is located on the Atlantic coast of the Delmarva Peninsula (Figure la). Isle of Wight and Assawoman Bays are the two northem-most coastal bays in Maryland. Fenwick Island, part of the barrier Island/southern spit unit of the Delmarva coastal compartment (Fisher, 1967), separates the coastal bays from the Atlantic Ocean. The bays are underlain by unconsolidated Coastal Plain sediments, the upper-most 60 m of which are Cenozoic in age. Sediments of the Sinepuxent Formation are exposed along much of Maryland's coastal area from Bethany Beach, Delaware, southward to the Maryland-Virginia border and directly underlie the study area (Figure lb). The Sinepuxent Formation was described by Owens and Denny (1979) based on information from drill holes along Sinepuxent Neck, the designated type locality for the Formation. The Sinepuxent Formation is composed of dark colored, poorly sorted, silty fine to medium sand with thin beds of peaty sand and black clay. Heavy minerals are abundant and consist of both amphibole and pyroxene minerals. All of the major clay mineral groups: kaolinite, montmorillonite, illite and chlorite, are represented. The sand consists of quartz, feldspar and abundant mica (muscovite, biotite, and chlorite). The high mica content makes the Sinepuxent Formation lithologically distinct from underlying older units (Owens and Denny, 1979). The Sinepuxent Formation is interpreted to be a marginal marine deposit. Owens and Denny (1979) had assigned a mid-Wisconsin age (24-30 ka) to the formation based on C" data. Later studies correlated the Sinepuxent Formation to the offshore Q2 deposits which were determined to be of oxygen-isotope Stage 5 age (between 80 to 120 ka) based on amino-acid racemization (Toscano, 1992; Toscano and others, 1989; Toscano and York, 1992). Within the study area, the Smepuxent is underlain by the Beaverdam Sand Formation which is Pliocene in age (Owens and Denny, 1979) (Figure lb). The western edge of the Sinepuxent formation lies against the Ironshire Formation which consists of pale yellow to white sand and gravelly sand. Although the Ironshire Formation sits unconformably on top of the Beaverdam, at no point does it underlie the Sinepuxent Formation (Owens and Denny, 1979). 6 7r 7S* JERSEY anon Point Dwa 0 MARME', SAY MARYLAND .......... ... . Lc@-Wlwy Kent Wand ...... t . ..... :... INN M. f C11 ............... ... .. TUDY AREA CILY Bluff ............ ............ ............ 61 LafKIhV .......... wail" Bluff Ir VIRGM MRGU4W 0 10 2D 3D 40 50 KLOMEM a 10 20 30 NILES C:9 0 @@NEW e $am@ (DE @K Figure 1. A) Generalized geologic map of'central Delmarva Peninsula (from Owens and Denny, 1979). See Figure IB for pattern key. 7 N METERS 30- Greenwood, S Delaware 20- ............. . . . . . . . . . . . . . . . . . 10 A IRONSHIRE ... . .... ... .. Assateague Island, Nz Maryland SEA LEVEL jT So-called "YORKTOWNP) and COFIANSEYR)" 20- 30 -J UPLANATION MARINE MARGINAL MARINE ESTUARINE-FLUVIATILE Sinepuxent x" " I- n 110 Kent Islard Formation lronshire Formation Omar ...... Formation ........... ...... . Waiston ...... =. Sut Beaverda Sand Yorktown Formation (not shown on imp) "YOrktOIAM and Cohanse.,A?)" Pensauken (not shown on map) Formation 07 Chesapeake Gcoup, urdvWed St Mary's Formation Choptank Formation Cahmt Formation g. Figui-e 1. B) Cross-section showing stratigraphic relationship of formations (from Owens and Denny, 1979), with pattern key. 8 PHYSICAL CHARACTERISTICS Assawoman Bay and Isle of Wight Bay are microtidal (<2 in tidal range) coastal lagoons and are contiguous with each other. For this discussion, the boundary between Assawoman Bay and Isle of Wight Bay is the Rt. 90 bridge which spans Fenwick Island (Ocean City at 60th Street) and Isle of Wight (Figure 2). Table I lists the basic morphometric data for both bays. The surface area statistics presented in Table I differ from those presented in the previous year (Wells and others, 1994). The differences are attributed to 1) differences in methods used to calculate areas, and 2) extent of surface areas included in the statistics. For this study, surface areas include the areal extent of the sampling which covers the lower tidal reaches of the tributaries as well as the bays themselves. Table 1. Morphometric data for Isle of Wight and Assawoman Bays. Dimension and area statistics were compiled from data from this study. Surface areas include the lower tidal reaches (i.e.- to the first major bifurcation) of the major tributaries. Drainage area values are from UM and CESI (1993). _TTwo Bay System Assawoman Bay Isle of Wight Bay Surface area 21.5 km2 24.1 kM2 45.6 kM2 Maximum length 7.9 kin 6.7 kni 14.5 kin Maximum width 3.3 km 4.3 kin U Drainage area 24.7 km' 146 kM2 170.7 kM2 Assawoman Bay, the northern-most bay, has a water surface area of 19.5 km2 and is elongated in north-south direction. The length of Assawoman Bay, measured from the mouth of Roy Creek to Rt. 90 bridge, is 7.9 kin. Maximum width of Assawoman Bay is 3.3 km. Greys Creek and Roy Creek have a combined surface area of 1.9 kM2. Isle of Wight Bay has a surface area of 17.2 kM2 . The length of this bay, from Rt. 90 Bridge to the west end of the north jetty at the inlet, is 6.7 km. Maximum width is 4.3 km. The surface area of the St. Martin River, from the mouth (at Ocean Pines) to the juncture of the Bishopville Prong and Shingle Landing Prong, is 5.4 kM2 . The combine surface area of Turville/Herring Creek and Manklin Creek is 1.5 kM2. The St. Martin River is the major tributary, accounting for 62% of the total drainage area for the bays (Bartberger and Biggs, 1970; UM and CESI, 1993). Drainage area for Isle of Wight Bay is about 6 times the area of the bay itself (Table I). On the other hand, the drainage area of Assawoman Bay is about equal (1.1 times) to its surface area. In all, the drainage area for both bays is about 4 times as large as their open water areas. For comparison, the watershed basin for the Chesapeake Bay is 28 times its open water area. As a result of the relatively small drainage area combined with flat topography, fresh water input into the two coastal bays is small. The limited fresh water input and restricted access to open ocean contribute to poor flushing of the bays (Bartberger and Biggs, 1970: UM and CESI, 1993). 9 75* 12' 75*8' 75' Uttle Assawoman Bay 38*28' Delaware The "Ditch" Maryland 6110 Idantego ay CZ Assawoman Q) Bay Al, RY,7ep Bayside P ?Vovs C.) 38'24' Isle of RL 90 Wight Ocean Pines Isle of Wight Day Bayshore Estates Cape Isle at Clee Wight 0 Mallard Island L) to 0 Rt. so SCALE Ocean City 0 10 00 2000 3000 meters Oeean City Inlet 0 5000 10000 feet Figure 2. Study area. 10 The two bays are connected to the Atlantic Ocean through a single outlet, Ocean City Inlet, located at the extreme south end of Isle. of Wight Bay. Ocean City Inlet had formed during a hurricane in 1933 and was immediately stabilized by jetties to keep it opened. Historically, several other inlets have been documented along Fenwick Island (Truitt, 1968). These inlets also formed during storms as did the Ocean City Inlet, but were eventually filled in as a result of natural processes. During the March 1962 storm, also known as the Ash Wednesday Storm, Fenwick Island was breached near 71st street. A channel approximately 50 ft wide was cut through to the bay (U.S. Army Corps of Engineers, 1962a). The Army Corps of Engineers immediately filled in the inlet with sand dredged from Assawoman Bay. The bays are very shallow, the average depth less than 2 m (Figure 3). Generally, areas with depths greater than 3 m are a result of dredging. Some of the deepest areas are within the Federal Navigation Channel, which is maintained at -10 m. These deep areas are located in the southern end of Isle of Wight Bay. Other artificially deep areas include numerous dredged holes in Assawoman Bay and along the east side of Isle of Wight Bay. The material dredged from these holes were used to fill in low-lying areas on Fenwick Island for development, or used as beach fill to replenish the beach in Ocean City after the March 1962 storm. These holes vary in depth from 4.9 to 9.8 in. Another artificially deep area is within a canal known as "The Ditch", the depths of which average 4.5 m. This canal connects Assawoman Day to Little Assawoman Bay (in Delaware). Circulation patterns and tidal ranges in the two bays are dependent on proximity to the inlet and wind conditions. Near the inlet, currents are primarily an effect of tidal cycles. Currents over 200 cm/sec are common near the inlet and within the Federal Navigation channel. Tidal amplitudes, based on data from NOS tide stations located in southern Isle of Wight Bay, range from 0.78 to 0.55 m. Tidal influence diminishes rapidly with increasing distance from the inlet. Along the western and northern margins of the bays, wind conditions have a greater effect on water levels and current velocities. Salinity in the two bays decreases slightly with increasing distance from Ocean City Inlet. Maximum salinity measured during the summer (Casey and Wesche, 1981) ranged from 30 ppt near the inlet to 26 ppt in Assawoman Bay just north of the Rt. 90 bridge. Salinity tends to be higher in the summer due to limited freshwater input and high evaporation. Bordering the bays are wetlands and marshes, found mainly along the western margin. Much of the bay side of Fenwick Island has been developed at the expense of wetlands (Dolan and others, 1980). Large areas have been filled in and built up, and much of natural shoreline has been armored by bulkheads or rip-rap. 75'12' 75*8' 75' Bathymetry based on surficial sample depths lAttle 1 meter contour interval Assawoman depth below MSL Bay - 38'28' Delaware Maryland Z - 38724' 2 2 2 Ttly-ville Cree 2 2 38*20' SCALE Ocean City 0 1000 2000 3000 meters 0 5000 10000 feet Figure 3. Bathymetry of Isle of Wight and Assawoman Bays based on surficial sample depths. 12 METHODS SURFICIAL SAMPLE COLLECTION Surficial sample collection was conducted onboard an 18 ft whaler. A Magnavox MX300 GPS system with MX 50R DGPS Beacon (U.S. Coast Guard) Receiver was used for navigation. The accuracy of the system is A: 3 to 5 meters. A sampling grid based on 500 by 1000 meter spacing was used to determine sample locations. Sample spacing east-west across the bays was 500 meters. Longitudally down the bays the samples were spaced 1000 meters. Bottom sediments were expected to show the greatest textural variation laterally (east-west) across the bay as opposed to longitudally along the bays axes. In order to adequately document these changes, the tighter spacing laterally across the bays was adopted. An even tighter sampling spacing was used in the southern end of Isle of Wight Bay where abrupt changes in textural composition of sediments were anticipated due to the flood-tidal delta feature and the Federal navigation channel. Samples were collected in the major tributaries approximately every 500 meters and as far upstream as the first stream bifurcation. Sample locations are shown in Figure 4. Latitude and longitude for each stations are presented in Appendix I (Table X). Sediment samples were collected using a hand operated stainless-steel dredge sampler which sampled a bottom surface area of 19 cm x 14 cm. Upon collection, the samples were visually described and then placed in Whirl-Pak Tm bags. Field descriptions of the samples are presented in Appendix I (Table XI). LABORATORY ANALYSES Textural Analyses Sediment samples were analyzed for water content and grain size (SAND, SILT, CLAY content). Water content was calculated as the percentage of water weight to the weight of the wet sediment using equation 1. Water 10() W: where: W., is the weight of water; and W, is the weight of wet sediment. Water content was determined by weighing 30 to 50 grams of sediment, drying the sediment at 65'C, and then reweighing the dried sediment. Dried sediments were saved for chemical analyses (see Chemical Analyses section). 13 I 1 1 75* 12' 75'8' 75* Surficial Sediment Little Sample Locations Assawoman Bay 3 8'2 8' 2 0 Delaware Maryland 1;110 07 so 16 '20 Oil 12 '13 '14 '15 17 is 21P 47 .28 .29 o3o 22623 4 0 25 (:@@ 3 - 3:7P C34 360 3? )41 3 3Gb 40 41 .42 .43 CU .46 47 Q) 04,9 050 CP1 052 o53 :'55 '83 982 616, 6 8 0 a OW 't9 '%6D 6 ,79 077, -76 "75 38'24' '85 74 o7 07 7 .4 o69 m67 o6a 065 4 6 '87 98 'S 9 .101 .102.103,10 lDO 94 '93 106. 95,98 97 .98 cpo .109.108.107 olZD 110. Iko N23'1 I a 917 al leci L-4- lg4 .129 141 139P b26 10 25 013001310134,135, 13 14 Turville Cree 1 ?,7 '132 0136 14LO 3 40VP J33 11 149 915a 154 1;;15 5 16 'P 188 16 38'20' 6 6 Ocean City SCALE 0 1000 2000 3000 meters 0 5000 10000 feet Figure 4. Surficial sample locations, 14 SAND, SILT and CLAY contents were determined using the textural analysis detailed in Kerhin and others (1988). Sediment samples were first treated with 10% solution of hydrochloric acid (HCI) to remove carbonate material such as shells and then treated with a 6 to 15% solution of hydrogen peroxide (H20,) to remove organic material. The sediments were then passed through a 62 micron mesh sieve separating SAND from the mud (SILT + CLAY) fraction. Mud fractions were analyzed using a pipette technique to determine SILT and CLAY contents. Weights of the SAND, SILT and. CLAY fractions were converted to relative proportions (weight percentages). The sediments were categorized according to Shepard's (1954) classification based on percent SAND, SILT and CLAY components. The results of the textural analyses are listed in Appendix II (Table XII). Chemical Analyses Sediments dried for water content determination were analyzed for total elemental nitrogen, carbon and sulfur contents and six metals. The dried sediments were pulverized in tungsten-carbide vials using a ball mill, then placed in Whirl-Pak Tm bags, and stored in a desiccator. Nitrogen, Cilrbon, and Sulfur Analyses The sediments were analyzed for total nitrogen, carbon and sulfur (NCS) contents using a Carlo Erba NA1500 analyzer. Approximately 10 to 15 mg of dried sediment were weighed into a fin capsule. The exact weight (to the nearest gg) of the sample was recorded. To enhance complete combustion during the analysis, 15 to 20 mg of vanadium pentoxide (V,05)were added to the sediment. The sediment sample, contained in a tin capsule, was dropped into a combustion chamber where the sample was oxidized in an atmosphere of pure oxygen. The resulting combustion gases, along with pure helium used as a carrier gas, were passed through a reduction furnace to remove free oxygen and then through a sorption trap to remove water. Separation of the gas components was achieved by passing the gas mixture through a chromatographic column. A thermal conductivity detector was used to measure the relative concentrations of the gases. The NA1500 Analyzer 'was configured for NCS analysis using the manufacturer's recommended settings. As a primary standard, 5-chloro- 4-hydroxy- 3-methoxy- benzylisothlourea phosphate was used. Blanks (tin capsules containing only vanadium pentoxide) were run at the beginning of the analyses and after 12 to 15 unknowns (samples) and standards. Replicates of every fifth sample were run. As a secondary standard, a NIST reference material (NIST SRM #1646 - Estuarine Sediment) was run after every 6 to 7 sediment samples. Table 11 presents the comparisons of the MGS results and the certified values for total carbon, nitrogen and sulfur contents for the NIST standard. There is excellent agreement between the NIST values and MGS's results. 15 Table 11. Results of nitrogen, carbon, and sulfur analyses of NIST-SRM #1646 (Estuarine Sediment) compared to the certified or known values. MGS values were obtained by averaging the results of all SRM analyses run during this study. Element Analyzed Certified Values* MGS Results (% by weight) (this study) Nitrogen 0.211 0.18 �0.04 Carbon 1.72 1.67 �0.08 Sulfur 1 0.96 1 0.99 �0.08 The value for carbon is certified by NIST. The sulfur value is the non-certified value reported by NIST. The value of nitrogen was obtained from repeated analyses inhouse and by other laboratories (Haake Buehler Labs and U.S. Dept. of Agriculture). Metal Analyses Sediments were analyzed for six metals: chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn). These metals were selected for several reasons. 1) These metals are non-volatile. As opposed to volatile metals, these metals are less likely to be lost during analytical procedures used in this study. 2) Studies have shown that these metals can be used as environmental indicators (Hennessee and others, 1990; Hill, 1984; Cantillo, 1982.- Sinex and Helz, 1981). 3) Comparable data for these metals are available for the Chesapeake Bay (Cantillo, 1982; Helz and others, 1982; Hill and others, 1985; and Sommer and Pyzik, 1974) and for other estuaries (Sinex and Helz, 1981). Concentrations for the six metals were determined using a microwave digestion technique, followed by analyses of the digestate on an Inductively Coupled Argon Plasma unit (ICAP). The microwave digestion technique is detailed in Wells and others (1994). A Thermo Jarrel-Ash Atom Scan 25 sequential ICAP was used for the metal analyses. The wavelengths and conditions selected for the metals of interest were determined using digested bottom sediments from the selected sites in the Chesapeake Bay and reference materials from the National Institute of Standards and Technology (NIST SRM #1646 - Estuarine Sediment; NIST SRM 92704 - Buffalo River Sediment) and the National Research Council of Canada (PACS-1 - Marine Sediment). The wavelengths and conditions were optimized for the expected metal levels and the sample matrix. Quality control was maintained by comparing unknown samples to the 3 standard reference materials (SRM's): NIST 41646, NIST 42704, and PACS-1. SRMs and blanks were run with each set (10 to 15 samples) of unknowns. Check (calibration) standards were also run every 15 to 20 samples or approximately every hour of run time to check instrument drift. Replicates of every tenth unknown (sample) were run. 16 Results of the analyses of the three standard reference materials are compared to the certified values in Table III. The MGS's results indicate better than 90% recovery for all of the metals except Mn. The lower recovery values for Mn (for NIST SRM #1646 and PACS-1) may be due to incomplete digestion during sample preparation. Table III. Results of metal analyses of standard reference materials compared to the certi ied values. Certified Values MGS Results Metals ES* PAC* BR* % 'I ES* % PAC* % recove recovery recovery Cr 135 76 113 133 98.3 79 104.0 107 94.5 (gg/g) :�:5 �3 �8 �3.9 �2.2 �2.94 Cu 98.6 18 452 96 96.9 15 82.5 440 97.2 (Ag/g) �5 �3 �16 �2.2 �0.6 �8.08 Fe (%) 4.11 3.35 4.87 3.90 95.9 3.20 95.8 4.45 91.4 �0. I =EO. 1 �0.12 �0.3 �0.3 �0.38 Mn 555 375 470 572 103.1 329 87.8 370 78.7 (Ag/g) �19 �20 �12 �41.8 �33.2 �37.3 Ni 44.1 32 44.1 37 83.2 27 85.0 36 81.2 (vg/g) �3 �3 �2 :1-2.6 :L2.2 �1.6 Zn 438 138 824 420 95.9 120 86.8 800 97.1 (gg/gjj -- �12 -L �6 �22 1 �3.8 �0.7 �8.69 *BR NIST-SRM #2704 - Buffalo River Sediment *ES NIST SRM #1646 - Estuarine Sediment *PAC= National Research Council of Canada PACS-1 Marine Sediment Data Reduction All statistical analyses of textural and chemical data were performed using Statgraphics Plus, Version 6.0 (Manugistics, Inc., 1992). TR*Tl 17 RESULTS AND DISCUSSION SEDIMENT TEXTURE Based on the textural analyses of 171 surficial sediment samples, the average textural composition of the bay bottom sediments is 54% SAND, 28% SILT and 18% CLAY. The SAND to mud ratio is nearly 1: 1, similar to the findings for Chincoteague sediments reported by Bartberger (1976). Bottom sediments include seven of the ten Shepard's (1954) classifications. Most of the samples fall in the SAND and the CLAYEY SILT classifications. The third most common sediment type represented is SILTY SAND. Table IV presents a summary of the classification of the surficial sediments. Table IV. Summary of sediment classification and areal extent for each classification mapped in Isle of Wight Bay and Assawoman Bay. SBEPARD'S (1954) Percent of total Areal extent of CLASSIFICATION Number of samples samples class mapped (km 2 SAND .73 43 19.3 SILTY SAND 20 12 6.5 CLAYEY SAND 2 1 a SANDY SILT 6 4 0.9 SAND SILT CLAY 7 4 0.3 CLAYEY SILT 52 30 14.4 ILTY AY 11 6 2.5 TOTAL 171 100 43.8b Areal extent was not calculated; less than 0.1 kM2. Totals may not add due to rounding . Distribution of sediment type is shown in Figure 5. The trend is an eastward (seaward) increase in grain size of bottom sediments. Sandy sediments (i.e. SAND > 75%), which cover approximately 44% of the bottom of the two bays, are found primarily along the eastern side of the bays. CLAYEY SILTS, which cover approximately 14% of the study area, are found in the tributaries and in isolated pockets associated with marshy shorelines. SILTY CLAYS are restricted to upstream areas of the tributaries. SILTY SANDS, SANDY SILTS and SAND- SILT-CLAYS are found in isolated pockets along marshy shorelines and along the boundaries between SANDS and CLAYEY SILTS. The boundary areas represent zones of mixing between 18 75*12' 75*8' 75' Sediment little Assa-v@oxnan Distribution Bay 38*28' sici S SICI Delaware S aryland CISi Sisk S.Si asi Sisk Is c1si sas sasici Sa Sisk Sisk Q@ as* sici cisi Sa C) 38@24' cisi CI Sisk Sisk - MY S. Sa Sj CI cisi 75 sa S cl ee cis, A.Si a Sisk - ,-@/ c S. CIS' S.Sic@@ c1sa cisi 14 as sasic) ici 2 Isi S. Sisk sasi Si Sa.d Silt S.sic 0 Shepard's Classification Sisk 38*20' CIISi SCALE Ocean City 0 1000 2000 3000 meters 0 5000 10000 feet Figure 5. Distribution of sediment type based on Shepard's (1954) classification. 19 the coarse (SAND) and fine grained end members (SILTY CLAY and CLAYEY SILT) of the sediment distribution. However, the transition between mud and SAND dominated areas is quite abrupt for most of the bays. Sediment distributions reflect energy environments as well as proximity to source of sediments. SAND found along the western side of the bays represents material carried across the barrier island (Fenwick Island) as washover or eolian deposits, or carried through the inlet. These areas are shallower and exposed to a relatively large fetch. The bottom in these areas are subject to higher energies from wind generated waves. Fine grained sediments either are not being deposited or are actively being winnowed from these higher energy areas. At the southern end of Isle of Wight Bay, large SAND shoals have been deposited as part of the flood tidal delta associated with the inlet at Ocean City. Based on vibracores collected on these shoals in 1981/82, the central flood tidal delta is estimated to be 4.2 in (14 ft) thick and contains medium to fine SAND (Wells and Kerhin, 1982). The SAND dominated area around Isle of Wight is interpreted to be reworked SAND from the exposed pre-transgression surface which seismic data show outcropping in this area. This exposed surface is interpreted to represent a former footprint of a larger Isle of Wight. Along the main stem of the bays, SAND sediments vary in thickness from several cm to more than 8 meters, gradually thinning toward the west. Estimates of thickness are based on data from a series of borings collected in 1962 by the U.S. Army Corps of Engineers (1962b). Locations of the 1962 borings are shown in Figure 6. Figure 7 shows the approximate thickness of the sandy sediments (sediments having median diameter of greater than 0.1 mm) based these borings. The boring data did not differentiate the modem SAND deposits from underlying older SAND deposits (i.e. Pleistocene sands). Surface portions of the SAND deposits had been dredged for material to repair the beach in Ocean City after the Ash Wednesday Storm in 1962. Approximately 870,000 in' (1.03 X 106 yds') of SAND were removed from the back bays for beach reparation (Evert, 1985; U.S. Army Corps of Engineers, 1980). Figure 8 depicts changes in bathymetry since 1962 for selected areas along the eastern side of the bays. Bathymetric changes are based on comparisons of water depths reported for the 1962 borings to those for the surficial samples collected for this study. Since 1962, selected areas, particularly along the central axis of the bays, have been deepened by dredging. Some of these areas correspond those areas where surface SAND deposits were greater than 6 in (20 ft) thick. It is assumed that most of the material excavated from the bays to repair the beach in 1962 were taken from these deepened areas. Since 1962, additional material has been dredged from the back bays, either to be used for fill to build up low lying areas for development in Ocean City, or to create channels for boat access to marinas and private boat slips. SILTY CLAYS, and CLAYEY SILTS are confined primarily to marsh areas and tributaries. CLAYEY SILT dominated sediments are found at the lower reaches of the tributaries and at "lobes" extending from the tributaries into the main bay areas (Figure 5). SILTY CLAY sediments are found in the upper reaches of the tributaries. Sources of the fine-grained deposits are from sediments contained in surface run-off and from shoreline erosion. The study area is 20 75'12' 75'8' 75* Boring Locations borings collected in 1962 Little by the U.S. Army Corps of Engineers, Baltimore District Assawoman Bay - 38*28' Ok Delaware Maryland )K2 , 0 Xl-*84 026 Oat so W21 R 07 Q) 057 24X7 X33 3e4 3R-' -W )a4 02 075 - 38*24' P 67 A, )K63 061 66X 64 X 6 40X 72 C eek 4k 0 6 42 43, 45 V W20' 46 SCALE Ocean City 0 1000 2000 3000 meters 1 1, 1 @ @ , 1, 1 @ 1, 0 5000 10000 feet Figure 6. Location of borings collected in 1962 by the U.S. Army Corps of Engineers. 21 75* 12' 75*8' 75' Thickness of Surficial Sand Deposits Little based on borin.-s collected in 1962 Assawoman by the U.S. Army Corps of Engineers, Baltimore District Bay 3 8'2 8' 3 meter contour interval Delaware Maryland IP 3 0 0 0 38*24' 3 3 0 0 Turvile Creek 0 W 38'20' SCALE Ocean City 0 1000 2000 3000 meters i .I 1H 11, 1'111 0 5000 10000 feet Figure 7. Thickness of the SAND sediments based the 1962 borings. 22 75'12' 75*8' 75' BATHYMETRIC CHANGES since 1962 Little at selected areas Assawoman Bay 0.3 meter (I foot) contour interval 38*28' Delaware Maryland St Q) 3624 *4 le c,,, e 0 38@20' SCALE Ocean City 0 1000 2000 3000 meters @ 1 11 11 ,i 111 11 , Ii 0 5000. 10000 feet L Figure S. Bathymetric changes since 1962 at selected areas in Isle of Wight and Assawoman Bays, 23 underlain by the Sinepuxent Formation which was described by Owens and Denny (1979) as being sandy with layers of black clay and peat beds. During shore erosion processes, the finer grained material is selectively removed, suspended, and deposited in areas where wave action is minimal, such as in the protected marshy areas (i.e.- areas of limited fetch) and in deeper mid- channel areas (i.e.- below wave base). Based on seismic data collected during the previous year's study (Wells and others, 1994), the CLAYEY SILT deposits are estimated to be up to 5 meters thick in the area east of the mouth of the St. Martin River (due south of Isle of Wight Bay). This area corresponds to the thalweg of the St. Martin paleochannel. WATER CONTENT Correlation analyses of water contents as well as SAND, SILT, CLAY, carbon, nitrogen and sulfur contents for all sediment samples were performed to detect any significant associations between variables. The correlations were done using Pearson product-moment technique (Johnson and Wichern, 1982). The resulting correlation matrix is presented in Table V. Table V. Correlation matrix for nitrogen, carbon, sulfur contents and sediment textural data based on all surficial sediment samples. Correlation analysis was conducted pairwise to include all samples and to utilize all non-missing values for each parameter whenever possi e. BDL entries were treated as missing parameter values. Values listed in the table are Pearson correlation coefficients (r). Significant levels for all values are less than 0.01 (critical value of r at 99% = 0.479). %Carbon %Nitrogen %Sulfur %H20 %Carbon 1.000 %Nitrogen 0.915 J.000 - %Sulfur 0.964 0.852 1.000- - %H20 0.887 0.796 0.879 1.00.0 %SAND -0.814 -0.698 -0.840 -0.956 %SILT 0.665 0.541 0.698 0.873 %CLAY 0.884 0.792 0.911 0.946 The amount of water a sediment holds is strongly influenced by grain size, with fine grained sediment holding more water. The correlation coefficient values presented in Table V confirm this relationship. Water contents are strongly associated with the CLAY component of the sediment as reflected by the high correlation coefficient between percent water and CLAY content (r = 0.95). By the same token, water contents show a strong inverse relationship with SAND content (r = -0.96). Association between water content and SILT content (r 0.87) is weaker. 24 The relationship between water contents and grain size is further exemplified in Table VI which summarizes mean values for water, nitrogen, carbon and sulfur contents for each sediment type. Water contents of SAND sediments average 21.6% while SILTY CLAY sediments have the highest water contents ( maximum value = 79%). Table V1. Summary of water content, percent nitrogen, carbon and sulfur for each sediment type. Sediment Type Number Mean [Shepard's (1954) of Classification] samples Water Nitrogen Carbon Sulfur (% wet weight) (0/6 dry -ight) (% dry weight) (% dry weight) SAND 73 21.6 0.06* 0.31* 0.03* =f:4.7 �0.06 �0.25 �0.05 SILTY SAND 20 38.5 0.09 1.21 0.28 �8.0 =1:0.09 �0.62 �0.12 CLAYEY SAND 2 47.1 0.1 0.81 0.15 r. A Y.7 �0.21 �1.15 �0.22 SANDY SILT 6 47.7 0.11 1.91 0.60 �5.7 �0.09 �1.03 �0.26 SAND SILT CLA 7. 55.9 0.24 2.76 0.72 �6.7 �0.07 �1.03 �0.35 CLAYEY SILT 52 59.9 0.25 3.60 1.17 �6.7 �0.13 �1.49 �0.42 SILTY CLAY 11 69.9 0.44 6.49 2.21 �3.3 �0.11 �1.83 �0.57 *Number of SAND samples used to calculate means for nitrogen, carbon, and sulfur values is 63. Ten SAND samples were not analyzed for chemistry due to the difficulty in grinding the coarser SAND particles in preparation for analyses. GEOCHEMISTRY Carbon The carbon found in sediments consists of both inorganic and organic components. Studies of the Chesapeake Bay sediments have shown that inorganic carbon component is minor, contributing less that 18% to the total carbon content (Hennessee and others, 1986; Hobbs, 1983). Shell fragments accounted for the bulk of inorganic carbon measured in Chesapeake Bay sediments. Although shell fragments were often noted in the surficial samples (refer to Appendix 25 I for field descriptions of the sediments), they were not as abundant compared to Chesapeake Bay sediments. Therefore, it is assumed that inorganic carbon contributes little to the total carbon measured in the coastal bay sediments. Total carbon contents measured in the surficial sediments range from 0 to 9.86% with a mean value of 2.08% which are similar to those values reported for the Chesapeake Bay (range = 0 to 10.5%; mean = 2.1%; Hennessee and others, 1986) and for other pristine estuaries (Folger, 1972). Folger observed that organic carbon contents for fine-grained sediments from estuaries not subjected to high pollution seldom exceeded 5% and were often less than 3%. However, in this study, the high carbon values (>7%) were obtained from silty clay sediments collected in the upstream areas of Roy and Greys Creek and St. Martin River. Sample 83 which was collected in Bishopville Prong of the St.. Martin River contained 9.86% carbon. This sample did not contain obvious peat material or any other material that would account for the high carbon value. Some of the carbon most likely came from sources containing high organics such as run-off associated with the poultry industry and agriculture practices and discharge from sewage treatment plants (Bishopville) into the St. Mar-tin River. Correlation analysis reveals strong associations between carbon content and % water (r 0.89) and CLAY (r = 0.88) (Table V), indicating that carbon content is associated with the fine grained fraction. This relationship is well illustrated in Figure 9 which presents the areal distribution of carbon content. Carbon content distribution closely follows the sediment distribution. Nitrogen Nitrogen contents in surficial sediments range from 0 to 0. 5 9%, and average 0. 16%. These values are lower than the mean and maximum values obtained from the cores samples from the first year study (Wells and others, 1994). The core sediments included samples containing peat which yielded very high nitrogen values (maximum contents = 1.39%). None of the surficial samples analyzed for this study contained appreciable peat material. Results of correlation analysis of nitrogen, carbon, and sulfur contents with textural data show that nitrogen is moderately associated with CLAY content (r = 0.792). The highest nitrogen contents are associated with SILTY CLAYS found in upstream areas of the tributaries (St. Martin River, Greys Creek and Roy Creek). Nitrogen content of the sediments is strongly associated with carbon content (r = 0.915). The strong relationship between nitrogen and carbon reflects the fact that nitrogen comes primarily from organic geopolymers found in the sediment (Hill and others, 1992). Therefore, nitrogen is expected to maintain a fairly constant proportionality with carbon content depending on the nature of the organic source. Ratios of nitrogen to carbon (N/C) range from 0.007 to 0.916 with a mean value of 0.142 =E 0.16. The mean is slightly higher than the mean ratio of 0. 113 obtained from sediment cores collected in the Chesapeake Bay (Hill and others, 1992), but is lower than the Redfield's (1963) ratio of 0.176 for planktonic organisms. The intermediate value for the ratio of nitrogen to carbon seen in the coastal bay sediments reflects a combination 26 75* 12' 75'8' 75" Carbon Content Surficial Sediments Little Assawoman 1% contour interval Bay 38'28' 54 2 Delaware Maryland 2 Q) AfOpti Ri 2 38724' 4 3 .2 '3 eek 2 Turville Creel, -j- Q) 0 V 38'20' SCALE Ocean City 0 1000 2000 3000 meters 0 5000 10000 feet Figure 9. Distribution of total carbon content in surficial sediments for Isle of Wight and Assawoman Bays. 27 of organic material types contained in the sediments. N/C values for terrestrial derived carbon sources are lower than those for marine sources (Jeffrey Cornwell, Horn Point Environmental Lab- unpublished data). In the two coastal bays, N/C values are generally low ( mean = 0.065) for sediments in the tributaries and along the marsh island areas between Greys Creek and Roy Creek, suggesting that nitrogen in sediments comes from terrestrial organic material, probably as cellulose plant tissue. N/C values are higher, averaging 0. 177, for the sediments collected in the central portions of Isle of Wight and Assawornan Bays. In these areas plankton is most likely the primary source of nitrogen in sediments. Nitrogen loadings into the St. Martin River were estimated to be 10 to 18 times the loadings into Assawoman and Isle of Wight Bays (UM and CESI, 1993). Although some of the highest nitrogen values were obtained from St. Martin River sediments, nitrogen contents for the river sediments average 0.36%, 2 to 3 times those values obtained from sediments collected in other portions of the study area. Furthermore, nitrogen content values are lower than expected given the high carbon content in the sediments (i.e.- mean N/C = 0.060). The relatively low N/C ratios may be attributed, in part, to the terrigenous source of organic material. In other words, the river sediments do not contain excessive amounts of nitrogen. This suggests that, in spite of the high nitrogen loadings for St. Martin River, very little nitrogen is being preserved in the sediments. Sulfur Sulfur in sediments is found primarily as inorganic metal sulfides and elemental sulfur. These sulfur species form as a result of a bacterially mediated reaction during which organic carbon is oxidized using dissolved sulfate (SO,-') from seawater as an oxidant (Bemer, 1967, 1972; Goldhaber and Kaplan, 1974). During the process that occurs under anaerobic conditions, sulfate is reduced to sulfide. The sulfide reacts with ferrous iron (Fe") forming an iron monosulfide precipitant which further reacts with elemental sulfur to form FeS2 (pyrite and its polymorph, marcasite) (Berner, 1970). Total sulfur contents of the surficial sediments of the two coastal bays range from 0 to 3.16% about a mean of 0.63%. The range and mean are slightly higher than those values reported for sediments from Maryland's portion of the Chesapeake Bay (range = 0-2.0%, mean = 0.56% ;Hennessee and others, 1986) and Virginia's portion of ihe Chesapeake Bay (range = 0-2.0%; mean = 0.35% ; Hobbs, 1983). As with nitrogen and carbon contents, SILTY CLAYS collected in the tributaries yielded the highest sulfur contents, ranging from 1.41 to 3.16%. Distribution of total sulfur content in surficial sediments is shown in Figure 10. Correlation analyses show a strong association between sulfur and CLAY content (r 0.91) and water content (r = 0.88). Correlation between sulfur and SILT is weaker (r = 0.70). The strong correlation between sulfur and CLAY content suggests that sulfur is best preserved in clayey sediments as opposed to silty sediments. Clayey sediments typically have high water contents which accounts for the strong correlation between sulfur and water content. These results are consistent with those of the Chesapeake Bay (Hennessee and others, 1986). 28 75* 12' 75*8.' 75* Sulfur Content Little Surficial Sediments Assawoman Bay 0.5% contour interval 38*28' Delaware Maryland Is, 10, 0.5 1.5 t j, 3.0 2.0 38'24' 1.5 1.5 1 o.5 Cree I.D D 14 0 Ip 38'20' x SCALE Ocean City 0 1000 2000 3000 meters i ''I II , @ I, I @ 11 0 5000 10000 feet Figure 10. Distribution of total sulfur content in surficial sediments. 29 The ratio of carbon to sulftir (C/S) averages 3.56 � 1.32 for all samples. This value is much higher than the C/S ratio of 2.8 (� 1.5) for modern marine sediments reported by Berner and Raiswell (1984). The higher C/S values may be related to the nature of the carbon contained in the sediments. A significant portion of the total carbon measured in many of the coastal bay sediments may be non-reactive carbon, perhaps in the form of plant detritus. Plant detritus is less susceptible to bacterial decay compared to algal debris and therefore is more likely to be preserved (Goldhaber and Kaplan, 1975). However, there is no apparent distribution pattern of the C/S ratio values as there is with N/C ratio values. If abundant plant material contributed to higher C/S values, then one would expect sediments collected in the tributaries to have high C/S values. The mean of 3.29 for C/S values for sediments collected in the marsh and tributaries is slightly lower than the mean (3.72) for main bay sediments. Abundant worm tubes as well as algae mats were noted in many of the surficial samples collected in the main bay areas. These tubes and algae may have contributed to the amount of non-reactive carbon, thus accounting for the proportionately high carbon content in these sediments. Metals Correlation matrix for metal concentrations, carbon, nitrogen and sulfur contents, and sediment texture is presented in Table VII. Most correlations between the variables are moderate to strong (r > 0.7). These correlations are similar to those calculated for the core sediments (refer to Wells and other, 1994). The highest correlations are between Fe and Cr (r = 0.984), Fe and Mn (r = 0.956) and Cr and Zn (r = 0.953). There are also high correlations between CLAY content and Cr, Fe, and Ni, and between water content and all six metals. These metals typically are associated with clay minerals as they are either components of the mineral lattice structure or absorbed onto clay surfaces (Cantillo, 1982). Clay minerals comprise a significantly large portion of the fine (CLAY size) sediment fraction. Likewise, all metal concentrations except Cu show a strong inverse relationship with SAND contents (r > 0.89). Metal concentrations for surficial sediments are within the range of those obtained from an earlier study in the two bays (Allison, 1975). For comparison, average Zn concentrations for fine grained sediments from the Baltimore Harbor (Sinex and others, 1981; Sinex and Helz, 1982) are twice the highest concentration (see sample 83) measured in this study. Cr levels in Baltimore Harbor sediments are three times as much as the highest values obtained in this study. Therefore, it is in the opinion of the authors of this report that the levels of metal concentrations measured in the coastal bay sediments are not excessive. Unfortunately, there are no EPA action levels or threshold limits for metal in sediments at this time. Nor is there any standard method for determining significance of trace metal content in sediments. It is not within the scope of this study to determine if metal levels in sediments are detrimental to the environment. Instead, the objective is to document the existing levels of metals in the sediment, establishing a baseline with which future comparisons may be made. Because of the wide range of sediment types analyzed in the study, comparisons of absolute metal concentrations between the surficial sediments are very difficult. Therefore, several techniques for the treatment of metal data are used to account for the differences in metal concentration due to textural composition of the sediments. Once metal data are "normalized" with respect to textural differences, trends in the spatial distribution of metals ate easier to realize and interpret. 30 Table V11. Correlation matrix for trace metal concentrations and sediment textural data based on all surficial sediment samples. Correlation analysis was conducted pairwise, to include all samples and utilize all non-missing values for each parameter whenever possl le. BDL entries were treated as missing parameter values. Values listed in table are Pearson correlation coefficients (r). Significant levels for all values are less than 0.01 (critical value of r at 99% 0.479). Cr Cu. Fe Nin Ni Zn Cr 1.000 - CU 0.830 1.000 - Fe 0.984 0.791 1.000 - Mn 0.940 0.679 0.956 1.000 - Ni .0.928 0.808 0.921 0.843 1.000 - Zn 0.953 0.896 0.933 0.859 0.931 1.000 % SAND -0.972 -0.760 -0.971 -0.933 -0.892 -0.910 % SILT 0.888 0.554 0.899 0.888 0.752 0.776 % CLAY 0.960 0.874 0.945 0.861 0.930 0.965 %H20 0.960 0.833 0.963 0.907 0.895 0.928 % Nitrogen 0.745 0.759 0.732 0.653 0.720 0.815 % Carbon 0.835 0.786 0.834 0.751 0.813 0.905 % Sulfur 0.868 0.789 0.863 0.768 0.840 0.927 Enrichment Factors To reduce the effect of grain size, metal concentrations may be discussed in terms of enrichment factors (EF). The use of enrichment factors also allows for comparisons of sediments from different environments and the comparisons of sediments whose trace metal contents were obtained by different analytical techniques (Cantillo, 1982; Hill and others, 1990; Sinex and Helz, 1981). 31 Enrichment factor is defined as: EFM - -(X1Fe).,.pk_ (2) (X1Fe),,,,., where: EF(,,) is the enrichment factor for the metal X; X1Fe(,..PL.) is the ratio of the concentrations of metal X to Fe in the sample; and X1Fe(,..f..,.,:,e) is the ratio of the concentrations of metal X to Fe in a -reference material, such as an average crustal rock. Fe is chosen as the element for normalizing because anthropogenic sources for Fe are small compared to natural sources (Helz, 1976). Taylor's (1964) average continental crust is used as the reference material. Average crustal abundance data may not be representative of the coastal bay sediments because there is a higher proportion of SAND in the bay sediments compared to the average crustal rock. However, abundance data is useful as a relative indicator. Enrichment factors for the five metals in the surficial sediments are listed in Appendix II (Table XIV). The average enrichment factor values are almost identical to those calculated for the core samples for the first year study (Wells and others, 1994) and are within those values obtained for other coastal bays not subjected to industry (Sinex and Helz, 1981). The surficial bay se'diments are enriched in Cr and Zn with respect to crustal rock. The average enrichment factor values for Cr and Zn are 1.31 and 2.54, respectively. Distributions of EF values for Cr indicate no discernable pattern. However, distribution for EF values for Zn show areas of higher enrichments in the tributaries (EF > 3). Surficial sediments generally are not enriched in Cu, Mn, and Ni relative to average crustal rock. EF values average less than one for Cu and Ni (0.51 and 0.61, respectively) and one for Mn. The low values for Cu and N1 do not necessarily signify the area is depleted in these metals, but instead reflect the unsuitability of the reference material with respect to this particular study area (Wells and others, 1994). Vai-iation from Historical Norms The "degree" of metal enrichment in sediments relative to a regional norm or historical levels can be assessed by correlating trace metal concentrations with grain size composition (Hennessee and others, 1990; Hill and others, 1990). During the first year study of Isle of Wight and Assawoman Bays, a series of shallow sediment cores were collected and analyzed for metals. 32 Based on the downcore decrease in enrichment factor values, metal concentrations of sediments below 30 cin in the sediment column were interpreted to represent the historical norm for the coastal bays (Wells and others, 1994). Metal concentration values for these sediments (i.e. sediments below -30 cm) were fitted to the following equation: X = a(SAND) + b(SIL7) + e(CLAI) (3) where: X is the metal of interest; a, b, and b are the proportionality coefficients determined for the SAND, SILT and CLAY components, respectively; and SAND, SILT, and CLAY are grain size fractions of the sediment sample. Using an algorithm developed by Marquardt (1963), least square coefficients were estimated. The results are presented in Table VIII. The correlations are excellent for all of the metals. The values for the coefficients indicate that CLAY fractions account for a significant amount of the metal concentrations. Table V111. Least squares coefficients for metal data. Metal c oncentration values for sediments sampled below 30 cm in cores collected during the first year study were fitted to Equation 3. Estimates of coefficients Cr Cu Fe Mn Ni Zn SAND 5.4905 0.97712 0.12284 37.682 3.43225 5.158017 SILT 32.8062 5.83 1.24878 166.7049 13.37438 25.15979 CLAY 173.0266 14.374 7.8523 691.4095 50.4597 127.3579 R@ 0.9505 1 0.9042 1 0.9536 1 0.823282 1 0.9006 1 0.92221 By substituting the least squares coefficients from Table VIII in equation 3, "predicted" metal concentrations were calculated for the 171 surficial sediments. These predicted metal concentration values represent the expected historical or background levels of metals based on grain size composition of the sediment. To determine variations from historical norms, the predicted metal concentrations were compared to the measured values using the following equation. 33 Variationx Measuredx - Predictedx (4) Pre&ctedx Negativ e values indicate depletion and positive values indicate enrichment relative to background levels. Variation values calculated for core sediments below 30 cm, in the sediment column were analyzed according to Gaussian statistics. Variation values for all metals exhibited near-normal distributions with mean values close to zero. Mean variation values and standard deviations for each metal are presented in Table IX The standard deviation ((Y), a measure of dispersion of values, provides a convenient means to identify significantly high or low variation values calculated for the surficial sediments. For example, in a normal distribution, 68% of the values fall within Icy of the mean; 95.5% of the values fall within 2a of the mean. Values greater than Ry ( 3 sigma levels), are considered significant beyond the natural population dispersion. Table IX. Mean and standard deviation (a) of the variation values calculated for sediments below 30 cm in the sediment column. The mean and 3(y values are used to identify significantly low or high variation values. Metal Mean T a 2cy _T 3cF Cr 0.01 � 0.17 � 0.34 0.50 Cu -0.02 � 0.23 � 0.46 0.69 Fe 0.05 � 0.28 =L 0.57 0.85 Mn 0.00 +0.21 � 0.43 0.65 Ni 0.02 � 0.27 � 0.54 0.82 Zn 0.01 � 0.20 � 0.39 0.60 Variation values for each metal were calculated for the surficial sediments and are presented in Appendix II (Table XV). Variation values for Cu and Zn average close to one indicating that surficial sediments contain twice the amount of Cu and Zn over background levels (historical levels). Most variation values for Cu and Zn for surficial sediments exceed 30 levels, and are interpreted to be significantly high values. These results agree with the results of the previous years study (Wells and other, 1994). Both zinc and copper are ubiquitous in that these two metals are commonly used in marine related industries. Zn is widely used as a sacrificial anodizing coat or plate applied to a variety of metal products that will be subjected to salt water corrosion. Copper is in the chemical compound used to impregnate wood for maine use and is used as an anti-blofouling agent in marine paints. 34 Distribution of Variation Levels Variation values for Zn were mapped in terms of sigma levels and are presented in Figure 11. The distribution reveals a very interesting pattern, one that does not follow the sediment distribution. Instead, the distributions reflects anthropogenic influences within the two bays. The distribution also demonstrates the degree of sensitivity of this technique for assessing metal enrichment within the study area. For most of Isle of Wight Bay and southern Assawoman Bay, zinc is between 3 and 6 sigma levels above background. There are a few areas characterized by lower sigma level (between 0 and -3) along the eastern side of Assawoman Bay and in "the Ditch". These areas correspond to dredged areas where modem sediments have been removed, exposing older material that has not been enriched with zinc. Another area marked by low sigma levels is evident near the inlet. The zero-sigma level contour outlines the Federal navigation channel. In this area, relative enrichment of zinc is minimized by several factors. 1) The Federal channel is periodically dredged by the Army Corps, removing sediment contaminated with zinc. 2) Strong tidal currents flush the area, preventing the deposition of zinc contaminated sediments. High variation levels for zinc were calculated for sediments collected in the St. Martin River. Values fall between 6 and 9 sigma levels. Sediment sample 483, collected in the Bishopville Prong of the river, yielded a variation value 11.8 sigma levels above background. These variation values indicate that the fine-grained sediments in the St. Martin River act as a sink for zinc. Other studies have identified the St. Martin River as receiving a considerable Zn loading (as well as other pollutants) (LIM and CESI, 1993). There are several other areas characterized by high Zn variation values (>6 a levels) but the sediments are not as fine-grained as those found in the St. Martin River. These areas are adjacent to marinas and developments having a large number of boat slips (i.e.- Cape Isle of Wight.and Bayside Key - refer to Figure 2 for locations). The elevated zinc levels in sediments are most likely related to the high boat activity in these areas. These developments usually contain dead-end canals and marina basins which normally have restricted circulation, thus allowing contaminants to accumulate in the sediments. Interestingly, the sediments in most of these areas are not particularly fine grained, but are SAND and SAND-mud mixtures. There are two "hot spots", characterized by exceedingly high variation levels (up to 12-15 c; levels). One hot spot (defined by samples 107, 111, 113, 139 and 140) is located north of Bayshore Estates and bayside of the Ocean City Convention Center. The second (defined by samples 154, 155, and 156) is located on the west side of Isle of Wight Bay, opposite of Mallard Island. The sediments at both of these "hot spots" are classified as SAND. Variation levels for the other metals are also significantly high in sediments from these two areas. Run-off enriched in metals from the large parking lot at the Convention Center may contribute to the "hot spot" north of Bayshore Estates. At this time there is no obvious explanation for the hot spot opposite of Mallard Island. The authors theorize that there may be a local source for the metals, such as a buried barge or automobile (or auto parts). Distribution of variation levels for Cu reveals a somewhat similar pattern (Figure 12). Variation levels generally are within 3 sigma levels for large portions of the bays. Variation 35 75* 12' 75* 8' 75 Zn Variation from background levels Little Assawoman surficial sediments Bay 38'28' sigma level distribution 0 Delaware Maryland 3 33 .......... 3 0 0, Q) 3 'kill 3 8'2 4' sigma level 0 Af 3 6 6=3 9 TUrville Cr,, 03 :3 0 12 15 38*20' SCALE Ocean City 0 1000 2000 3000 meters 0 5000 10000 feet Figure 11. Distribution of sigma levels for Zn variation from background levels in surficial sediments. 36 75* 12' 75*8' 75' Cu Variation from background levels Little surficial sediments Assawoman Bay sigma level distribution 38'28' Delaware Maryland 3 cz Q) 3 38'24' sigma level 0 0 @ic-. I-h 3 eek 40 9 Ttlrville ic ee - 14 ----------- 12 >2 0 38*20' SCALE Ocean City 0 1000 2000 3000 meters i, @, 'I , @ , (, .1 , @I 0 5000 10000 feet Figure 12. Distribution of sigma levels for Cu variation from background levels in surficial sediments. 37 levels are greater that 3 sigma levels for the fine-grained sediments collected in Greys and Roy Creeks and are even higher (6 to 9 cy levels) in the upstream area of the St. Martin River. Along the bay side of Fenwick Island and in southern Isle of Wight Bay are several pockets of high Cu variation levels, several of which correspond to the high Zn areas. Many of these pockets are adjacent to developed shorelines with man-made canals and a large number of boat slips. Copper leachates from marine paint and wooden bulkheads (constructed with chromated-copper-arsenate treated wood) accumulate in the sediments at the bottom of these poorly flushed canals. Some of the highest sigma levels were obtain from sediments collected either in canals (stations 17, 141, and 171), or within a meter from wooden bulkheads (stations 63 and 140). The sigma levels for Cr, Fe, and Mn are less than 3 a levels for most stations. Sigma levels for Ni are even lower, within I to 2 cy levels. However, sediments collected at 17 stations yielded significantly high variation values (>3 cy levels) for both Fe and Mn. Some of these sediments (stations 101, 104, 107, 111, 112, 154, 156, and 159) are located within the "hot spots" previously described. The variation levels for Cr, 'Cu and Zn are also high for these samples. The high variation values for the metals are attributed to contamination from a local source. The rest of the sediments having high variation levels for Fe and Mn are either randomly located (stations 18, 60, 63, 66 and 114), or concentrated along the shoaling areas in southern Isle of Wight Bay (stations 131, 134, 136, 137, 140, 146, and 148). All of theses samples are classified as SAND. The SAND fractions from these samples contain higher amounts of heavy minerals compared to other surficial sediment and compared to the core sediments used in calculating the background levels. Conceivably, heavy minerals transported into the bay through the inlet would be found in concentrated pockets along the tidal shoal. The relatively higher heavy mineral concentrations contained in these sediments would account for the high variation levels of Fe and Mn over background levels. CONCLUSIONS The distribution of sediments types in Isle of Wight and Assawoman Bays is very similar to that for Chincoteague Bay (Bartberger, 1976) and Rehoboth and Indian river Bays (Chrzastowski, 1986). These bays correspond to Folger's (1972) category of bays having small tidal range and limited sediment input from landward sources. In these bays, the bottom is dominated by sand transported in by overwash processes, inlet related delta formations and from winnowing action by wave in shallow areas. Finer grained sediments (SILT and CLAY) are restricted to deeper channel areas and in tributaries. Carbon, nitrogen and sulfur contents for most of the surficial coastal bay sediments are within the range expected for marine sediments. Carbon, nitrogen, and sulfur contents are strongly related to the texture of the sediments, with higher values associated with finer grained sediments. The highest values were obtained from SILTY CLAYS collected in the upstream areas of the tributaries. Very high values for carbon were obtained from several sediment samples collected in the upstream area of the St. Martin River. These high values are thought to be excessive and reflect high nutrient input in the river. This is one of the first studies to measure total nitrogen in the sediments. Data from this 38 study provide some clues as to the nature of nitrogen and its cycling within the bay ecosystem. Nitrogen contents relative to carbon, expressed as N/C ratios, suggest that much of the nitrogen measured in sediments collected in the tributaries comes from terrestrial derived organic matter while nitrogen in sediments collected in main stem of the bays comes from planktonic matter. The low N/C values obtained from St. Martin River sediments suggested that, in spite of the high nitrogen loadings into St. Martin River Basin (UM and CESI, 1993), relatively little nitrogen is preserved in the sediments. Conversely, carbon to sulfur (C/S) ratios indicate a more complex nature of the organic matter found in the sediments. C/S ratios are higher than expected for marine sediments, particularly for those sediments collected in the main stem of the bay. The high C/S ratios are attributed to sediments having a disproportionately high amount of non-reactive carbon. This carbon is not metabolized during sulfate reduction, and thus is preserved in the sediments. The non-reactive carbon is attributed to the abundance worm tubes and algae mats collected with the surficial sediments. Further analysis is recommended to quantify the amount of non-reactive carbon contained in the sediments. Results of metal analyses yield no excessively high metal concentrations. Enrichment factor (EF) values relative to average crustal rock were calculated to be greater than one Zn and Cr and less than one for Cu, Mn, and Ni. EF values for both Zn and Cu are highest in tributaries where fine grained sediments are deposited. The highest values are found in the upstream areas of the St. Martin River. The low EF values, particularly for Mn, suggest that the reference material used to calculate the EF values probably does not adequately represent the sediments found in the study area. Although the.reference material used is questionable, the calculated enrichment factors for Isle of Wight and Assawoman Bays are similar to enrichment factors for other Atlantic coast bays in non-industrial regions (Sinex and Helz, 1981). These results agree with those obtained from core sediment analyzed during the previous year study (Wells and others, 1994). A second technique used to assess and compare metal levels correlates metal concentrations to textural composition. By comparing predicted metal levels based on textural composition with metal levels actually measured in the sediments, variation or enrichment over background levels may be quantified. This technique has been very successful in monitoring subtle increases in metals in bottom sediments around the Hart-Miller Island dredge. disposal site in the Chesapeake Bay (Hennessee and others, 1992; Hill and others, 1990). Likewise, results from this technique has proven particularly sensitive in defining areas in Isle of Wight and Assawoman Bays that are enriched in Zn and Cu over background levels. Because Zn and Cu are used in a variety of products, particularly those related to the marine industry, these two metals are ubiquitous in many of the coastal bays (Sinex and Helz, 1981; UM and CESI, 1993). So, it is not unusual to find the surficial sediments in the bays enriched in these two metals. Although high variation levels for Zn and Cu are generally associated with fine grained sediments, even higher levels are seen in several SAND dominated areas adjacent to developed shorelines. These areas are subjected to high boating activity and usually are bulkheaded along most of the shoreline. The developed shoreline contains dead-end canals and narrow boat slips, and thus by design, have poor water circulation, which contribute to the accumulation of these 39 'metals. Results from this study indicate that the St. Martin River acts as a natural sink for many pollutants. Variation levels for Zn and Cu, as well as carbon, sulfur and nitrogen contents, are higher for sediments in the St. Martin River compared to those from other areas in the two bays. These higher levels may be attributed, in part, to the fine grained nature of the sediments (SILTS and CLAYS) found in the St. Martin River. On the other hand, these levels also reflect the relatively high pollutant input into the river compared to other tributaries. Studies have indicated that Isle of Wight (via the St. Martin River) receives a particularly high proportion of combined pollutant loads of the four coastal bays: 57% of current metal loadings and 50% of projected loads contributed by the Maryland Coastal Bays watershed (UM and CESI, 1993). The drainage area for Isle of Wight is 32% of the total watershed for Maryland's coastal bay system. Assawoman Bay, by comparison, appears to be more pristine with regard to Zn and Cu enrichments. Because the watershed area of Assawoman Bay is very small compared to its surface water area, input of pollutants are minimal. Also, much of the shoreline along Assawoman Bay is natural and not developed or armored. These factors plus the fact that large areas within the main bay have been dredged, removing recently deposited (and likely enriched) sediments, result in Assawoman Bay sediments being less enriched with metals or contaminated with other pollutants. The variation technique for assessing and evaluating metal contamination in sediment provides a useful tool in identifying areas that are sensitive to anthropogenic activities. Although results from this method cannot determine the degree of impact on other components in the bay ecosystem such as benthic population, the results may be used as indicators of where contaminated materials are being deposited. These areas may be targeted for further, more intense investigation. ACKNOWLEDGEMENTS This study was supported by the U.S. Mineral Management Service and the Association of American State Geologist Continental Margins Program, and the Maryland Department of Natural Resources. The authors extend their appreciation to Jennifer Isoldi who assisted in the collection of the sediment samples, to Matthew Greenawalt who assisted in the initial preparation of the sediment samples and conducted the water content analysis, and to Michael Brayton, who conducted carbon, sulfur, nitrogen, and textural analyses on the sediments The authors are especially grateful to Richard Younger who expertly piloted the whaler during the sample collection. The authors also thank Randall Kerhin for his suggestions and comments. 40 REFERENCES CITED Allison, J.T., 1974 (revised March, 1975)'Maryland Coastal Basin (02-13-01) existing water quality conditions: Water Resources Administration, Draft Report, Maryland Dept. of Natural Resources, Annapolis, MD. Bartberger, C.E., 1976, Sediment sources and sedimentation rates, Chincoteague Bay, Maryland and Virginia: Joumal of Sedimentary Petrology, v. 46, p. 326-336. Bartberger, C.E., and Biggs, R.B., 1970, Sedimentation in Chincoteague Bay, in Natural Resources Institute, University of Maryland, Oct. 1970, Assateague ecological studies, Part IL Environmental threats, Contribution ff446, Chesapeake Biological Lab, Solomons, Md. 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Truitt, RN., 1968, High winds--high tides: a chronicle of Maryland's coastal hurricanes: University of Maryland, Natural Resource Institute, Educational Series No. 77, College Park, Md., 35 pp. University of Md. (UM), and Coastal Environmental Services, Inc. (CESI), 1993, Maryland's coastal bays: an assessment of aquatic ecosystems, pollutant loadings, and management options: submitted to Maryland Dept. of the Environment, Chesapeake Bay and Special Projects Branch, Baltimore, Md. U.S. Army Corps of Engineers, 1962a, The March 1962 storm along the coast of Maryland: Report of District activities during and immediately following the storm, Baltimore District, Baltimore, Maryland, 21 pp. 44 1962b, Emergency Durie Delaware-Maryland Line to Ocean City, Md.- Location and Log of bonings: File 52, Map 188, July, 1962, Baltimore District, Baltimore, Maryland. '1980, Atlantic coast of Maryland and Assateague Island, Virginia: Feasibility report and final environmental impact statement: Baltimore District, Baltimore, Md. Wells, D.V., Conkwright, R.D., and Park, J., 1994, Geochemistry and geophysical framework of the shallow sediments of Assawoman Bay and Isle of Wight Bay in Maryland: Maryland Geological Survey Open File Report No. 15, Baltimore, Md., 125 pp- Wells, D.V. and Kerhin, R.T., 1982, Geological analysis and re-evaluation of Isle of Wight shoals as a potential borrow site: report submitted to Tidewater Administration, 33 pp. 45 46 Appendix 1. Location data and field descriptions of sediment samples. 47 48 Table X. Coordinates (latitude and longitude) for surficial sediment sample locations. Coordinates are based on 1927 North American datum. Station Latitude Longitude Comments 4 DD MM SS.S DD MM SS.S 1 38 27 35.4 75 5 43.3 Roy Creek 2 38 27 28.2 75 5 33.1 Roy Creek 3 38 1 27 20.3 75 1 5 12.7 Roy Creek 4 38 27 8.4 75 5 10.8 Roy Creel, 5 38 27 7.5 75 4 50.6 Roy Creek 6 38 27 7.1 75 1 4 23.3 7 38 25 55.6 75 5 14.6 8 1 39 26 55.5 75 4 22.9 9 39 26 52.9 75 4 1.7 Station in the "Ditch", a canal connecting to Little Assawoman Bay 10 38 27 5.1 75 3 56.3 Station in the "Ditch" 11 38 26 26.2 75 5 46.1 12 38 26 36.2 75 5 25.3 13 38 26 35.6 75 5 9.3 14 38 1 26 35.8 75 4 50.2 15 38 1 26 35.6 75 4 31.3 16 38 26 35.5 75 4 9.5 17 38 26 28.8 75 3 46.0 In canal behind Montego Bay Trailer Park 18 38 26 18.8 75 4 13.8 Station <1 in from bulkhead at Montego Bay 19 38 26 14.6 75 5 21.9 20 38 26 29.8 75 7 19.5 Greys Creek; station in small cove with mixed shorelines- some rip-rap, marsh and bulkheads 49 Station Latitude Longitude Comments 9 DD NTM SS.S DD MM SS.S 21 38 26 14.5 75 6 55.0 Greys Creek 22 38 26 2.7 75 6 50.3 Greys Creek 23 38 26 2.5 75 6 1 32.5 Greys Creek 24 138 26 3.3 75 6 12.4 Greys Creek 25 38 26 3.4 75 5 53.5 Station -6 in from island 26 38 26 3.7 75 5 31.4 27 138 26 2.2 75 5 13.4 28 38 26 2.8 75 4 49.7 29 38 26 3.1 75 4 29.8 30 38 26 3.2 75 4 1 9.3 31 38 26 3.2 75 3 55.1 32 38 25 48. 2 75 6 17.9 Greys Creek 33 38 25 48.8 75 5 24.5 34 38 25 46.4 75 5 0.1 35 138 25 1 51.4 75 3 59.8 36 38 25 41.4 75 4 11.9 38 38 25 30.4 75 6 33.3 39 38 25 30.7 75 6 13.1 40 38 25 31.0 75 5 53.5 41 38 25 30.7 75 5 32.3 42 38 25 30.5 75 5 10.3 43 38 25 31.1 75 4 50.0 44 138 25 1 30.8 75 4 31.6 45 38 25 30.8 75 4 10.0 Station in dredged hole; 6 in water depth 46 38 25 14.3 75 6 23.9 47 38 1 25 15.3 75 5 21.9 50 Station Latitude Longitude Comments 9 DD MM SS.S DD MM SS.S 48 38 25 14.8 75 4 11.4 49 38 24 57.8 75 6 13.9 50 1 38 24 1 34.0 75 5 1 54.4 51 38 24 58.4 75 5 32.4 52 38 24 57.2 75 5 11.0 53 38 24 58.3 75 4 51.4 54 38 24 57.7 1 75 4 32.5 55 38 24 57.8 75 4 10.3 56 38 24 41.8 75 5 1 32.4 56 38 24 42.2 75 5 31.1 57 38 24 14.9 75 1 5 53.4 58 38 24 25.4 75 5 32.0 59 38 24 1 24.9 75 5 12.1 60 38 24 25.1 75 1 4 51.1 61 38 1 24 26.2 75 4 29.6 62 38 24 25.0 75 4 13.4 At Bayside Keys (88th St.); station between boat piers, -, 0.6 m from wooden bulkhead 63 38 24 23.5 75 3 553 In canal at Bayside Keys; station - I m from wooden bulkhead 64 38 24 53.6 75 4 8.7 65 38 23 53.2 75 4 30.7 66 38 23 53.1 75 4 49.6 67 38 23 53.0 75 5 10.1 68 38 1 23 52.7 75 5 32.4 69 38 23 53.1 75 5 53.2 70 38 23 53.0 75 6 13.6 51 Station Latitude Longitude Comments 4 DD MM SS.S DD MM SS.S 71 38 23 53.7 75 6 54.4 St. Martin River 72 38 23 53.8 75 7 13.9 St. Martin River 73 38 23 52.6 75 7 1 31.2 St. Martin River 74 1 38 23 53.7 75 7 52.7 St. Martin River 75 38 24 10.5 1 75 7 53.0 St. Martin River 76 38 24 8.3 75 8 12.7 St. Martin River 77 1 38 24 10.0 75 8 32.3 St. Martin River 78 38 24 24.9 75 8 33.4 St. Martin River 79 38 24 13.1 75 8 54.2 St. Martin River 80 38 24 25.1 715 9 14.8 St. Martin River 81 1 38 24 35.7 75 9 35.3 St. Martin River 82 38 24 37.4 75 9 56.1 St. Martin River 83 38 24 41.6 75 10 17.2 St. Martin River; at junction of Bishopvllle Prong 84 38 24 25.4 75 10 16.5 St. Martin River; atjunction of Shingle Landing Prong 85. 38 23 52.9 75 8 13.7 St. Martin River 86 38 23 37.6 75 8 -11.4 St. Martin River 87 38 23 38.0 1 75 7 52.6 St. Martin River 88 38 23 38.1 75 7 31.6 St. Martin River 89 38 23 38.0 75 7 13.9 St. Martin River 90 38 23 20.0 75 7 31.4 91 38 23 20.6 75 7 13.9 .92 38 23 1 21.1 75 6 54.3 93 38 23 6.2 75 7 6.4 1 94 38 23 2.2 75 7 40.0 95 38 22 48.8 75 1 7 32.0 96 38 22 48.8 75 1 7 13.5 52 Station Latitude Longitude Comments 9 DD MM SS.S DD MM SS.S 97 38 22 48.8 75 6 53.6 98 38 22 48.7 75 6 32.6 99 38 22 47.9 75 6 55.0 100 38 22 48.5 75 5 52.7 101 38 23 1 20.9 75 5 52.6 102 38 23 21.1 75 5 31.3 103 38 23 21.1 75 1 5 11.0 104 38 23 21.2 75 4 49.9 105 38 23 1 21.1 75 4 29.4 106 38 22 57.9 75 4 28.5 107 38 22 48.9 75 4 49.4 108 38 22 48.2 75 5 1 10.7 109 38 22 48.2 75 5 30.8 110 38 22 32.7 75 4 32.2 Bayside of approx. -45th St. 111 38 22 15.8 75 4 1 34.9 Bayside of Convention Center 112 38 --22 -1-6.1 _75- -4---l 50.6 113 38 22 15.3 75 5 31.1 114 38 22 15.8 75 5 31.1 115 38 22 14.9 75 5 52.9 116 38 22 15.4 75 6 12.4 117 38 22 15.4 75 6 31.1 118 38 22 15.8 75 6 54.5 119 1 38 22 15.8 75 7 13.2 120 38 22 32.5 75 7 31.3 121 38 22 22.1 75 7 52.0 Manklin Creek 122 38 22 17.0 75 8 10.9 Manklin Creek 123 1 38 1 22 1 12.7 1 75 1 7 1 9.0 1 53 Station Latitude Longitude Comments 9 DD MM SS.S DD MM SS.S 124 38 21 59.3 75 7 27.2 Turville/Herring Creeks 125 38 21 45.1 75 7 30.7 Turville/Herring Creeks 126 38 21 1 40.1 75 7 1 48.7 Turville/Herring Creeks 127 38 21 25.7 75 8 1.0 Turville/Herring Creeks 128 38 21 14.6 75 7 51.4 'Herring Creek 129 38 21 59.3 1 75 6 44.8 130 38 21 42.7 75 6 53.0 .131 38 21 43.1 75 6 32.4 132 38 21 27.3 1 75 6 28.4 133 38 21 10.9 75 6 26.2 134 38 21 43.3 75 6 11.6 135 38 21 43.3 75 5 51.5 136 38 21 27.2 75 5 48.8 137 38 21 43.3 75 5 32.0 138 38 21 43.6 75 5 10.6 Station -1 rn from wooden bulkhead 139 38 22 1.0 75 4 34.8 Bayside of Convention Center 140 38 21 41.7 75 -4 34.8 Station within 1.5 m from green wooden bulkhead at Bayshore Estates (-32 nd St.) 141 38 21 38.4 75 4 58.1 Dead-end. canal in Bayshore Estates, -0.5 m from wooden bulkhead 142 38 21 28.3 75 5 10.0 143 38 21 21.4 75 4 52.6 144 38 21 1 12 75 4 50.6 145 38 21 10.4 75 5 10.1 14 38 21 10.9 1 75 5 32.9 147 38 21 1 10.7 75 1 5 52.4 54 Station Latitude Longitude Comments 9 DD MM SS.S DD MM SS-S 148 38 20 59.7 75 5 28.7 Fed. Channel; 6 in water depth 149 38 20 49.9 75 5 33.4 150 1 38 20 1 52.1 75 5 1 12.8 151 38 20 48.1 75 5 7.4 152 38 20 37.9 75 5 12.8 153 38 20 38.5 75 5 27.2 154 1 38 20 39.4 75 5 1 42.1 155 38 20 30.1 75 5 46.1 156 38 20 28.4 75 5 35.0 157 38 20 15.4 75 5 25.2 158 38 20 23.7 75 5 15.1 159 38 20 10.6 75 5 22.5 160 38 20 10.0 75 5 28.9 161 38 20 -1-2.9 - 75 5--- 40@ 1 - - Station on -west edge of flood delta; very shallow 162 38 20 -42.2 75 5 53.-9-- 163 38- --20 --19.9 75 5 54.4.---- 164 38--- 20 1.7 75 46-.2--. 165 38 19- 59.6---. 75 .5-- ---36.8 166 38 19 58.7 75 5 28.3 Station north of Rt 50 Bridge; on edge of Fed. Channel 167 38 19 52.7 75 5 43.2 168 38 19 56.4 75 5 48.7 Station next to Shanty Town 169 38 19 46.6 75 1 5 32.3 170 38 19 38.3 75 5 39.8 Southern most station 171 38 20 56.4 75 4 55.6 -55 Table X1. Field descriptions for surficial sediment samples collected in Isle of Wight and Assawoman Bays. Samples were collected on April 26, 27, 28, 29 and 30, 1993. Station Water DepLh Description 1 0. 8 m (2.5 ft) Very thin flocculent layer on top very dark grey, almost black, thick mud; some plant material; very strong H2S odor 2 0. 8 m (2.5 ft) Very thin flocculent layer on top very dark grey, almost black, thick mud; some plant material; very strong H2S odor 3 1.2 rn (4 ft) Dark brown flocculent layer on dark grey mud; worm tubes; no F12S odor 4 1. 1 m (3.5 ft) Brown gelatinous flocculent layer over mottled dark grey to brown sandy mud with lots of plant material 5 1. 1 m (3.5 ft) Thin brown flocculent layer on mottled grey and black muddy sand; worm tubes 6 1.4 m (4.5 ft) Layer of green algae on flocculent layer; mottled g*rey- brown to black, soft, smooth mud; some plant material; slight H,S odor 7 0. 8 m (2.5 ft) Dark brown flocculent layer with worm tubes; mottled black to dark grey, gelatinous mud; no odor 8 1.8 m (6 ft) Layer of green algae on flocculent layer; mottled grey- brown to black, soft, slightly gritty mud; some plant material; worm tubes; slight H2S odor 9 2.7 m (9 ft) Layer of calcified(?) worm tubes on light brown muddy sand with some clay balls 10 3.4 m (I I ft) Thick layer of calcified(?) worm tubes on light brown muddy sand with some clay balls 11 0. 8 m (2.5 ft) Thin grey-brown flocculent layer on dark brown-grey to black thick mud; worms 56 Table XI (cont.). Field descriptions for surficial sediment samples. Station Water Depth Description 12 0. 8 m (2.5 ft) Thin grey-brown flocculent layer on top of dark grey to black (mottled) thick mud; plant material 13 1. 1 m (3.5 ft) Dark brown flocculent layer with worm tubes; mottled black to dark grey, gelatinous mud; no odor 14 1.8 m (6 ft) Brown flocculent layer on dark olive grey, smooth mud 15 1.8 m (6 ft) Brown flocculent layer with algae on dark olive grey, soft mud; worm tubes; no H2S odor 16 4.3 m (14 ft) Greenish-brown algae on dark brown, gritty, soupy mud; lots of worm tubes 17 5.2 in (17 ft) No flocculent layer; black mud; very strong H,S odor 18 0. 8 in) (2.5 ft) Grey-brown and dark grey, slightly muddy sand; some shell fragments; worm tubes 19 0.9 in (2.5 ft) Thin brown flocculent layer on sticky, dark brown-grey to black mud; some tube worms; strong 112S odor 20 0.6 in (2 ft) Thin brown flocculent layer on top; dark grey, cohesive, gntty mud; slight 112S odor 21 0.9 m (3 ft) Thin, speckled brown flocculent layer; dark grey, watery mud; no H2S odor 22 0. 9 m (3 ft) Thin brown speckled flocculent layer on top dark grey, almost black, gelatinous, watery mud; worms; very strong H2S odor 23 0. 8 m (2.5 ft) Thin grey-brown flocculent layer on top with small, live clams; grey gritty mud with brown peat; lots of plant material; H,S odor 24 0. 9 m (3 ft) Thin brown flocculent layer on dark grey to black, mottled, smooth mud; oxidized worm tubes 25 0. 9 in (3 ft) Dark green, very soupy mud with lots of plant material; no detectable H,S odor 57 Table XI (cont.). Field descriptions for surficial sediment samples. Station Water Depth Description 26 0.6 m (2 ft) Thin dark brown flocculent layer over dark grey cohesive mud; worm tubes; H2S odor 27 1.2 m (4 ft) Thick dark brown-grey flocculent layer with worm tubes; mottled black to dark grey mud with sand; no H2S odor 28 1. 8 m (6 ft) Dark reddish-brown flocculent layer on mottled brown- grey to black mud; plant material; no H2S odor 29 1. 8 m (6 ft) Dark brown to dark grey-black muddy sand; worm tubes; small crabs and one oysterdrill (gastropod) 30 1. 1 in (3.5 ft) Medium brown, medium to fi ne sand; some dark grey sand mixed in 31 0. 5 in (1. 5 ft) Brown-grey, medium to fine sand; worms and worm tubes 32 1.2 in (4 ft) Very thin flocculent layer; dark olive-grey, very watery, somewhat gritty mud; H.2S odor 33 0.6 in (2 ft) Brown flocculent layer on top; mottled dark grey and brown-grey sandy mud; worm tubes; no H2S odor 34 1. 5 in (5 ft) Brown flocculent layer on brown muddy sand; zones of reduced black muddy sand around plant matter; worm tubes 35 0.6 in (2 ft) Brown oxidized sand on top of medium grey, slightly muddy sand; algae strings 36 2.7 m (9 ft) Brown gelatinous flocculent layer on dark green sandy mud; strong H.S odor; worm tubes 38 0.9 in (3 ft) Speckled, grey to brown flocculent layer on top; dark grey, almost black, very watery mud; oxidized worm tubes throughout giving mud a mottled appearance 39 1. 5 m (5 ft) Dark grey, almost black, gelatinous mud; first grab had SAV (grass) and large worm tubes on top; no H2S odor 58 Table XI (cont.). Field descriptions for surficial sediment samples. Station# Water Depth Description 40 1.5 m (5 ft) Brown flocculent layer on top; dark grey, almost black, cohesive mud; worm tubes sticking out of the top surface; no H2S odor 41 1.5 m (5 ft) Brown flocculent layer on dark green-brown sandy mud; oxidized worm tubes. 42 1.8 m (6 ft) Brown flocculent layer on medium grey sandy mud; worm tubes; no odor 43 1.8 m (6 ft) Brown flocculent layer on dark olive-grey sandy mud 44 1.1 m (3.5 ft) Light brown grading down to medium grey fine sand; worm tubes; slight H2S odor 45 5.5 m (18 ft) Dark brown flocculent layer on dark grey gritty mud; slight H2S odor; some plant material 46 1.2 m (4 ft) Very thin flocculent layer on top; dark grey, slightly gritty, cohesive mud; worm tubes and live worms; no H2S odor. 47 2.1 m (7 ft) Brown flocculent layer on dark brown-grey mud with fine sand; some black reduced areas; no odor 48 1.5 m (5 ft) Brown flocculent layer with worm tubes; grey and black fine sand; worm tubes and algae; very slight H2S odor 49 1.2 m (4 ft) Brown flocculent layer on top; dark-grey mud; brown peat at bottom; mud has some shell fragments; worm tubes; H2S odor 50 1.5 m (5 ft) Very thin flocculent layer on top; dark olive-grey, gelatinous mud; no odor 51 1.8 m (6 ft) Very thin flocculent layer on top; dark olive-grey, smooth mud; no odor 52 1.5 m (5 ft) Dark brown flocculent layer on brown-grey fine sand 53 1.2 m (4 ft) Brown fine sand on top grey, very fine sand; worm tubes and algae; slight H2S odor 59 Table XI (cont.). Field descriptions for surficial sediment samples. Station 9 Water Depth Description 54 1. 5 m (5 ft) Brown flocculent layer on grey-brown muddy sand 55 0.6 m (2 ft) Clean tan to brown fine sand; worm tubes 56a 2.1 m (7 ft) Dark grey mud with some fine sand; worm tubes; no odor 56b 1.8 in (6 ft) Brown flocculent layer with collapsed worm tubes; dark grey to olive-grey, slightly gritty mud; no H2S odor; cottage cheese texture 57 1. 5 m (5 ft) Brown flocculent layer on top; grey-brown sandy mud; worm tubes; no H,S odor 58 1.8 m (6 ft) Dark brown flocculent layer; dark olive grey, smooth, gelatinous mud; live worms (polychaetes); no H2S odor 59 2.1 m (7 ft) Dark brown flocculent layer on top; dark olive-grey, slightly gritty mud; gelatinous worm tubes; no 112S odor 60 1.2 in (4 ft) Brown flocculent layer on top; dark grey to brown, fine sand;@some organic material; worm tubes; H2S odor 61 1. 1 in (3.5 ft) Grey-brown fine sand; several worm tubes 62 1. 5 m (5 ft) Brown flocculent layer over mottled, grey to black, muddy sand; grass clippings and plant material (station is in between boat piers and approximately 0.6 meter from wooden bulkhead) 63 0. 5 in (1. 8 ft) Fine brown sand mottled with black sand; algae and cut grass; no odor (station is approximately I meter from wooden bulkhead) 64 0. 5 m (1. 5 ft) Brown flocculent layer over brown-grey, slightly sandy mud; lots of plant material; strong H,S odor 65 1.2 m (4 ft) Brown, fine sand over dark grey fine sand; worm tubes; slight H,S odor 66 1. 5 m (5 ft) Brown, fine sand over dark grey fine sand; worm tubes; slight H,S odor 60 Table X1 (cont.). Field descriptions for surficial sediment samples. Station 9 Water D th Descrivtion - M_ 67 1. 8 in (6 ft) Brown flocculent layer over brown-grey muddy sand; some algae; lots of worm tubes 68 2.7 m (9 ft) Olive-brown flocculent layer over grey, sticky mud 69 1.5 m (5 ft) Brown to grey fine sand; worm tubes 70 0. 8 m (2.5 ft) Light brown flocculent layer on top of light grey and dark grey to black mud; some plant material; worm tubes; H2S odor 71 0. 9 m (3 ft) Dark brown flocculent layer over dark grey-black gelatinous mud; worm tubes; H,S odor 72 1.5 m (5 ft) Very dark brown flocculent layer on top of black to dark grey, slightly gritty mud; abundant organic matter; worm tubes; F12S odor 73 Dark green-grey, gritty mud 74 1.5 in (5 ft) Dark grey, slightly gritty, cohesive mud; worm tubes; odorless 75 Dark grey, almost black, slightly gritty mud; worm tubes; juvenile blue crab 76 Dark green-grey soft mud; slight H,S odor; lots of worm tubes; thin layer of red algae on top 77 Dark green-grey soft mud; strong H2S odor; lots of worm tubes; thin layer of red algae on top 78 1.2 m (4 ft) Dark green-grey soft mud; strong H2S odor; lots of worm tubes; thin layer of red algae on top 79 Dark green-grey soft mud; thin brown flocculent layer; red algae polychaete tubes 80 Dark brown-grey mud; H,S odor Lorance (depth finder) malfunctioned-, no depth sounding 61 Table XI (cont.). Field descriptions for surficial sediment samples. .Station 9 Water Depth Description 81 1. 2 m (4 ft) Dark greenish-grey, slightly gritty mud; some plant material; worm tubes; H2S odor 82 Dark greenish-grey, slightly gritty mud; some plant material; worm tubes; H2S odor 83 Dark grey, slightly gritty mud; lots of plant material; slight H,S odor 84 Very dark grey, slightly gritty firm mud; strong H2S odor 85 Dark green-grey, gritty, cohesive mud; odorless 86 5.8 m (19 ft) Black gelatinous mud; strong H,S odor; some red worms 87 1.5 m (5 ft) Dark brown flocculent layer on top of dark olive-grey mud; worm and worm tubes; odorless 88 1. 8 m (6 ft) Dark brown flocculent layer containing collapsed worm tubes, on top of dark grey to black gelatinous mud; H,S odor 89 2. 1 m (7 ft) Brown flocculent layer on top of medium grey, gelatinous, slightly gritty (fine sand) mud; worm tubes; odorless 90 1.5 m (5 ft) Dark brown flocculent layer on top of dark grey gritty mud; some worms; H2S odor 91 2.1 m (7 ft) Dark brown flocculent layer on top of dark olive-grey, slightly gritty, mud; some worms 92 1.2 m (4 ft) Fluffy brown flocculent layer on top of brown to grey muddy fine sand; odorless; worm tubes 93 1.8 m (6 ft) Medium brown flocculent layer containing worm tubes, on top of firm medium brown-grey mud LOTance (depth finder) malfunctioned; no depth sounding 62 Table XI (cont.). Field descriptions for surficial sediment samples. Stafion 9 Water Depth Description 94 4.6 m (15 ft) Reddish-brown flocculent layer on top of black gelatinous mud; strong 112S odor 95 1.8 m (6 ft) Reddish-brown flocculent layer on top of mottled grey and black fine sand; hard (calcified?) worm tubes 96 1.8 m (6 ft) Reddish-brown flocculent layer on top of fine sandy mud; worms and worm tubes; odorless 97 1.8 m (6 ft) Very thin brown flocculent layer on top of mottled dark grey and black mud; worms and oxidized worm tubes; odorless 98 2.1 in (7 ft) Brown-grey flocculent layer on top of medium brown to olive thick (firm) mud with black streaks; odorless 99 2.1 m (7 ft) Brown-grey flocculent layer on top of olive-grey mud; some grit 100 2.1 m (7 ft) Reddish-brown flocculent layer over cohesive, dark grey mud; odorless 101 1. 5 m (5 ft) Dark brown to dark grey fine sand; slight H,S odor 102 2.7 m (9 ft) Grey-brown flocculent layer with collapsed worm tubes, over brown-grey, soft, gritty mud; grass shrimp 103 1. 5 m (5 ft) Dark brown fine sand over dark grey, almost black, fine sand; slight H,S odor; few worm tubes and shell fragments; grass shrimp 104 1. 1 m (3.5 ft) Layer of dark brown, very fine sand over dark grey, very fine sand; plant material; small clam; odorless 105 3.0 in (10 ft) Dark brown flocculent layer over mottled black and dark grey mud; plant material; HS odor; dead algae and seaweed 106 1. 1 m (3.5 ft) Medium brown fine sand over medium grey fine sand; odorless; rooted SAV on top; worm tubes; polychaetes; grass shrimp; oyster drill eggs 63 Table XI (cont.). Field descriptions for surficial sediment samples. Station Water DWth Description 107 1.4 m (4.5 ft) Patchy reddish-brown flocculent layer on top of mottled grey and black, gritty mud; oyster drill (gastropod); odorless 108 1. 2 m (4 ft) Layered dark brown over dark grey, very fine sand; grass (SAV) 109 1. 8 m (6 ft) Brown flocculent layer containing red algae, over grey to dark grey, gritty sand; abundant worm tubes; odorless 110 0. 8 m (2.5 ft) Clean medium brown, medium to fine sand; slight H2S odor ill 0. 8 m (2.5 ft) Medium brown to grey, medium to fine sand with small oxidized (lighter brown) areas; plant material; grass shrimp 112 1.5 m (5 ft) Thin layer of reddish-brown flocculent overlying mottled medium and dark grey, gritty mud; oxidized burrows; shell fragments; worms 113 1.8 m (6 ft) Brown flocculent layer containing jelly(fish?) masses and collapsed worm tubes, over very dark grey, gritty mud; deeper layer of medium grey mud with oxidized worm burrows 114 1.8 m (6 ft) Medium brown muddy, very fine sand; lots of heavy minerals 115 2.1 m (7 ft) Brown flocculent layer containing worm tubes over mottled medium to dark grey, gritty mud 116 1.8 m (6 ft) Light grey, watery flocculent layer over medium grey- brown, slightly sandy, cohesive mud; worm burrows and casts (some oxidized); odorless 117 2.1 m (7 ft) Light grey, watery flocculent layer over medium grey- brown, slightly sandy, cohesive mud; worm burrows and casts (some oxidized); odorless 118 1.8 in (6 ft) Firm grey muddy sand; worm tubes, some collapsed, and live worms 64 Table XI (cont.). Field descriptions for surficial sediment samples. Station Water Depth Description 119 1. 8 in (6 ft) Reddish-brown flocculent on top of mottled dark grey and very black, slightly gritty, mud; oxidized burrows; odorless 120 1. 5 in (5 ft) Thin reddish-brown flocculent layer on top of mottled brown, grey, and black sandy mud; oxidized worm tubes 121 2.7 m (9 ft) Brown flocculent layer with worm tubes, over medium grey-brown, slightly gritty mud; slight 112S odor; worm tubes 122 0.9 m (3 ft) Thin brown flocculent layer on top of thin (approx. I min thick) black layer of mud overlying brownish-grey mud; H2Sodor; worms and oxidized burrows 123 1.2 m (4 ft) Mottled dark brown to black muddy sand; worm tubes; odorless 124 1. 5 in (5 ft) Brown flocculent layer with collapsed worm tubes, juvenile clams and some live worms, on top of very dark brown to black firm, slightly gritty, mud; odorless 125 1.2 in (4 ft) Reddish-brown flocculent layer over thin black layer over brown-grey mud; worms and worm tubes 126 1.2 in (4 ft) Brown to medium grey flocculent on top of very thin black layer of mud, then medium grey mud; slight H2S odor; worm tubes 127 1. 1 m (3.5 ft) Reddish-brown flocculent layer on top of mottled grey and black mud; collapsed worm tubes; H2Sodor 128 0. 8 m (2.5 ft) Patches of brown flocculent with jelly(fish?) masses on top of brown-grey, slightly gritty, soft mud; odorless 129 1.5 in (5 ft) Olive-grey flocculent layer over olive-grey gritty mud; oyster drill; collapsed worm tubes; odorless 130 1.4 in (4.5 ft) Brown-grey flocculent layer containing collapsed worm tubes, over dark brown-grey, slightly gritty mud; odorless 65 Table XI (cont.). Field descriptions for surficial, sediment samples. Station Water DWth Description 131 1. 5 in (5 ft) Light brown fine sand over dark grey-brown fine sand; worm tubes; strong H,,S odor; grass shrimp 132 1. 8 in (6 ft) Thin dark brown flocculent layer over grey-brown muddy sand; some shell fragments 133 0. 8 in (2.5 ft) Light grey flocculent layer on top of dark grey, gritty mud; green leafy SAV; H2S odor 134 0. 6 in (2 ft) Clean medium brown fine sand with grey streaks; shell fragments 135 0.9 in (3 ft) Clean medium brown fine sand with grey streaks; very few shell fragments 136 0.6- in (2 ft) Clean medium brown fine sand with grey streaks; shell fragments 137 0.9 m (3 ft) Brown to dark grey- medium sand; plant material; few shell fragments 138 3.7 m (12 ft) Brownish-grey medium to fine sand with some silt; some shell fragments; odorless 139 1.2 in (4 ft) Reddish-brown flocculent layer over cl ean mottled medium -grey muddy sand 140 0.6 m (2 ft) Light brown, fine san-d--,-worm tubes 141 1.2 in (4 ft) Dark brown flocculent layer over dark grey, gravely, sandy, mud; shell fragments; algae fibers"; odorless 142 1.8 in (6 ft) Medium brown to dark grey, almost black, medium sand; H2S odor 143 2.1 m (7 ft) Medium brown flocculent layer over dark grey, smooth mud; oxidized burrows; skunk odor 144 1. 5 m (5 ft) Brown flocculent layer over dark grey, slightly gritty mud; razor clams (Ensis); tube worms 145 0. 8 m (2.5 ft) Medium brown-grey fine sand; some shell fragments 66 Table XI (cont.). Field descriptions for surficial sediment samples. Station Water DMth Description 146 0. 5 in (1. 5 ft) Clean medium brown sand; some heavy minerals 147 0.6 m (2 ft) Reddish-brown flocculent layer over brownish-grey, slightly gritty mud; plant material; oxidized burrows; worms; slight H2Sodor 148 5.8 m (19 ft) Light brown, fine sand with some heavy minerals; fine shell hash on top 149 2.7 in (9 ft) Light brown, medium to fine sand with some coarse, clear quartz gravel; fine shell fragments 150 2.7 in (9 ft) Light brown, fine sand; few shell fragments 151 0.6 in (2 ft) Dark brown flocculent layer over dark grey, gritty mud; algae; slight H.,S odor; shell fragments 152 5.2 in (17 ft) Brown medium sand; abundant shell fragments (primarily mussels) 153 3.7 in (12 ft) Light brown, slightly muddy, very poorly sorted sand; shell fragments 154 1.5 in (5 ft) Brown, medium to coarse sand; shell fragments; worms 155 0. 8 m (2.5 ft) Brownish-grey, gritty flocculent layer containing seaweed and worms on surface, over medium grey, sandy mud; worm tubes; fishy odor; mussel shell on top 156 2.1 m (7 ft) Grey flocculent layer over muddy fine sand, sand browner on top and gradually becoming grey toward the bottom; plant material (roots); hermit crab; shell fragments; fishy odor 157 0.3 in (I ft) Fine, clean sand 158 1.5 in (5 ft) Brown medium sand; shell fragments and whole mussel shells 159 2.7 ni (9 ft) Light brown, medium sand with gravel; live clams and shell fragments (including an oyster shell); calcareous (limy?) worm tubes 67 Table XI (cont.). Field descriptions for surficial sediment samples. Station Water De th Description 160 0.3 in (I ft) Mottled grey to brown fine sand; shell fragments 161 0.3 m (I ft) Grey-brown with black streaks muddy fine sand; roots; worm tubes and worms; fishy odor 162 0.5 in (1.5 ft) Brown flocculent layer with green algae on top of dark grey mud; mud contains abundant algae; no odor 163 0. 9 in (3 ft) Reddish-brown flocculent layer on top of thin layer of brown gelatinous mud, over grey to black gelatinous mud; gritty grey mud at bottom of grab (-10 cm); strong H,S odor; algae masses throughout sample; skunk-like odor 164 2.1 m (7 ft) Black sandy mud; H2S odor; flocculent layer on top (in spite of current); live mussels 165 5.5 m (18 ft) Light brown, fine to medium, sand; live mussels and a few mussel shells 166 5.8 rn (19 ft) Light brown, fine to medium sand; shell fragments 167 0. 5 m (1. 5 ft) Light brown, clean medium sand; shell fragments 168 2.1 m (7 ft) Light brown, fine to medium, clean sand; shell fragments 169 4,6 in (15 ft) Light brown, clean, medium sand; shell fragments 170 2.1 rn (7 ft) Light brown, clean, medium sand; some graveland shell fragments 171 2.1 in (7 ft) Dark brown flocculent layer over medium grey, smooth mud; strong H,S odor 68 Appendix 11. Textural and geochemical data for sediment samples. I 69 I ------ 70 Table XII. Textural data for surficial sediment samples. Station Water Textural Component Shepard's Content (percent by weight) (1954) N Gravel Sand Silt Clay Mud Class.* Si + Cl 1 73.97 0.00 4.66 42.49 52.85 95.34 SiCl 2 71.46 0.00 4.38 52.15 43.48 95.63 Clsi 3 65.01 0.00 5.43 65.71 28.86 94.57 Clsi 4 51.01 0.00 71.99 18.78 9.23 28.01 SiSa 5 19.28 0.00 95.45 3.30 1.25 4.55 Sa 6 59.36 0.00 33.21 43.05 23.74 66.79 SaSICI 7 65.72 0.00 11.22 56.89 31.90 88.79 1 CISi 8 32.99 0.06 74.61 18.75 6.58 25.33 SiSa 9 17.52 0.00 74.39 20.77 25.62 SiSa 10 21.19 0.20, 99.80 0.00 0.00 0.00 Sa 11 69.19 0.00 1.21 57.14 41.65 98.79 CISI 12 67.52 0.00 4.21 57.86 37.93 95.79 CISI 13 64.60 0.00 31.17 45.80 23.02 68.82 SaSICI 14 57.82 0.00 5.21 67.34 27.45 94.79 Clsi 15 48.21 0.00 60.62 26.60 12.79 39.39 SISa 16 43.14 0.00 71.95 15.45 12.60 28.05 SiSa 17 79.28 0.00 2.48 39.44 58.09 97.53 j SICI 18 30.07 12.53 85.75 1.29 0.44 1.73 Sa 19 69.18 0.00 3.32 59.66 37.03 96.69 Clsi 20 68.46 0.00 17.75 39.87 42.38 82.25 Sicl 21 68.92 0.00 1.28 48.02 50.71 98.73 Sicl 22 1 68.75 0.00 0.70 58.17 41.12 99.29 Cisi 23 60.87 0.00 18.12 62.38 19.51 81.89 CISI @ 1' 901 6 - E58 4.8 5 24 58,59 1 0.00 5.73 65.51 28.76 94.27 Cisi 71 Station Water Textural Component Shepard's Content (percent by weight) (1954) Class.* Gravel Sand Silt Clay Mud S1 + CI 25 60.27 0.00 15.79 49.46 34.75 84.21 Clsi 26 63.66 0.00 7.83 58.17 34.00 92.17 Clsi 27 36.38 0.00 79.43 13.56 7.01 20.57 Sa 28 49.05 0.00 35.19 46.85 17.96 64.81 SaSi 29 25.49 0.00 81.17 9.83 9.01 18.84 Sa 30 18.85 0.00 96.27 0.57 3.16 3.73 Sa 31 1 28.21 0.00 93.08 1.77 5.15 6.92 Sa 32 60.67 0.00 14.17 53.71 32.12 85.83 Clsi 33 27.37 0.00 85.62 7.09 7.29 14.38 Sa 34 26.07 0.00 88.16 5.78 6.06 11.84 Sa 35 22.02 0.00 90.44 2.60 6.96 9.56 Sa 36 49.31 0.00 49.44 27.91 22.65 50.56 SaSICI 38 64.10 0.00 25.73 39,11 35.16 74.27 SaSICI 39 61.30 0.00 2.17 59.08 38.75 97.83 Clsi 40 56.19 0.00 2.25 66.99 30.76 97.75 ClSi 41 37.38 0.00 63.61 23.12 13.27 36.39 SiSa 42 35.70 1 0.00 69.89 17.46 12.64 30.10 Sisa 43 21.61 0.00 86.38 5.98 7.64 13.62 Sa 44 19.56 0.00 91.80 0.63 7.57 8.20 Sa 45 43.39 0.00 67.59 18.54 13.87 32.41 SiSa 46 53.75 0.00 15.22 55.46 29.32 84.78 CISI 47 40.14 0.00 71.70 18.09 10.21 28.30 SiSa 48 23.25 0.00 96.19 1.60 2.21 3.81 Sa 49 57.25 0.00 28.48 51.66 19.86 71.52 SaSi 59.68 0.00 5.95 1 64.49 1 29.57 1 94.06 1 CISI 51.70 0.00 14.77 58.80 26.42 85.22 ClSi 72 Station Water Textural Component Shepard's 9 Content (percent by weight) (1954) M Gra, vel Sand Silt Clay Mud Class.* Si + Cl 52 18.76 0.00 98.52 1.16 0.31 1.47 Sa 53 20.46 0.00 98.44 1.02 0.55 1.57 Sa 54 22.56 0.00 92.86 4.54 2.60 7.14 Sa 55 19.18 0.00 98.81 0.96 0.23 1.19 Sa 56.1 54.48 0.00 11.50 60.58 27.92 88.50 clsi 56.2 54.56 0.00 7.62 62.41 29.97 92.38 Clsi 57 24.94 0.00 86.80 8.28 4.92 13.20 Sa 58 54.87 0.00 10.05 62.01 27.94 89.95 1 Clsi 59' 46.37 0.00 38.14 45.63 16.23 61.86' SaSi 60 20.70 0.00 97.34 1.84 0.83 2.67 Sa 61 30.39 0.00 89.94 5.37 4.69 10.06 Sa 62 26.48 0.00 99.34 0.47 0.18 0.65 Sa 63 20.80 0.00 98.07 1.13 0.80 1.93 Sa 64 46.45 0.00 72.21 19.97 7.82 27.79 SiSa 65 19.50 0.00 99.72 0.43 0.00 0.43 Sa 66 18.53 0.00 98.72 1.03 0.25 1.28 Sa 67 30.63 0.00 88.76 6.38 4.87 11.25 Sa 68 55.08 0.00 16.16 53.03 30.81 83.84 Clsi 69 20.46 0.00 98.29 0.90 0.81 1.71 Sa 70 55.62 0.00 3.50 63,47 33.02 96.49 CISI 71 68.65 0.00 16.68 52.64 30.68 83.32 Clsi 72 75.19 0.00 7.68 52.42 39.91 92.33 CISi 73 60.93 0.00 3.12 66.32 30.55 96.87 ClSi 74 61.04 0.00 3.94 56.43 39.62 96.05 CISi 75 70.39 0.00 2.28 57.92 39.80 97.72 clsi 76 1 68.53 1 -0.00 1 1.94 1 54.88 1 43.17 Clsi 73 Station Water Textural Component Shepard's Content (percent by weight) (1954) N Gravel Sand Silt Clay Mud Class.* Si + Cl 77 68.49 0.00 1.96 51.83 46.21 98.04 CISI 78 64.36 0.00 2.13 50.68 47.19 97.87 Clsi 79 67.23 0.00 4.96 46.17 48.87 95.04 Sicl 80 70.25 0.00 2.71 44.07 53.22 97.29 Sici 81 70.85 0.00 5.94 42.02 52.04 94.06 SICI 82 74.19 0.00 3.77 35.66 60.57 96.23 Sicl 83 71.64 1 0.00 13.48 39.69 46.83 86.52 Sicl 84 71.10 0.00 2.74 35.30 61.96 97.26 SICI 85 61.41 0.00 6.41 50.90 42.69 93.59 ClSi 86 74.51 1 0.00 4.53 48.19 47.27 95.46 CISI 87 62.14 0.00 1 5.14 55.47 39.38 94.85 Clsi 88 58.25 0.00 2.64 58.61 38.75 97.36 Clsi 89 57.49 0.00 2.84 63.71 33.44 97.15 CISI 90 53.49 0.00 12.57 61.60 25.82 --- 87.42 ClSi 91 55.13 0.00 7.94 62.56 29.50 92.06 ClSi 92 30.25 0.00 82.41 11.74 5.86 17.60 Sa 93 52.54 0.00 4.51 67.71 27.78 95.49 Clsi 94 72.81 0.00 1.06 48.84 50.11 98.95 SICI 95 1 19.67 0.00 93.79 4.16 2.05 6.21 Sa 96 30.18 0.00 61.38 29.94 8.68 38.62 SiSa 97 49.86 0.00 12.39 67.51 20.09 87.60 c1si 98 48.14 0.00 9.58 67.10 23.32 90.42 CISI 99, 54.15 0.00 10.93 65.63 23.44 89.07 Clsi 100 55.22 0.00 14.33 55.64 30.03 85.67 CISI 25.76 98.05 1.50 0.45 1.95 Sa 102 38.28 0.00 58.17 1 25.16 1 16.66 41.82 SiSa 74 Station Water Textural Component Shepard's Content (percent by weight) (1954) Gravel Sand Silt Clay Mud Class.* Si+Cl 103 19.85 0.00 99.10 0.88 0.02 0.90 Sa 104 21.13 0.00 98.47 1.53 Sa 105 69.10 0.00 14.94 43.16 41.90 85.06 1 Clsi 106 23.35 0.00 99.15 0.85 Sa 107 22.39 0.00 91.70 5.72 2.57 8.29 Sa 108 18.27 0.00 98.40 1.53 0.08 1.61 Sa 109 28.07 0.00 78.70 12.72 8.58 21.30 Sa 110 17.81 0.00 99.37 0.63 Sa 111 19.83 0.00 100.00 0.00 Sa 112 19.96 0.00 90.18 6.63 3.19 9.82 Sa 113 32.18 0.00 78.22 13.78 8.00 21.78 1 Sa 114 21.80 0.00 90.10 7.04 2.86 9.90 Sa 115 42.04 0.00 56.96 29.55 13.49 43.04 SiSa 116 35.67 0.00 53.27 33.16 13.57 46.73 1 SiSa 11,7 41.63 0.00 50.84 35.19 13.98 49.17 SiSa 118 45.50 0.00 58.33 27.90 13.76 41.66 SiSa 119 42.62 0.00 32.37 53.26 14.37 67.63 SaSi 120 25.80 0.00 65.81 29.04 6.15 34.19 SiSa 121 55.46 0.00 19.35 52.49 28.16 80.65 CISi 122 49.18 0.00 25.15 56.02 18.84 74.86 SaSl 123 1 18.20 0.00 87.75 8.88 3.37 12.25 Sa 124 53.00 0.00 12.72 58.73 28.55 87.28 ClSi 125 69.51 0.00 2.83 57.90 39.27 97.17 cisi 126 61.84 0.00 11.79 58.71 29.49 88.20 CIS1 127 66.28 0.00 4.59 59.19 36.22 95.41 ClSi 128 68.49 0.00 1.46 54.24 1 44.31 1 98.55 ClSi 75 Station Water Textural Component Shepard's Content (percent by weight) (1954) (%) Gravel Sand Silt Clay Mud Class.* Si + Cl 129 45.60 0.00 66.32 22.36 11.32 33.68 SiSa 130 38.50 0.00 67.11 20.52 12.37 32.89 SiSa 131 21.71 0.00 95.43 3.95 0.61 4.56 Sa 132 22.78 0.39 91.33 5.54 2.74 8.28 Sa 133 41.51 0.00 37.44 51.38 11.18 62.56 SaSi 134 18.90 0.02 99.43 0.55 Sa 135 19.38 1 0.00 99.48 0.52 Sa 136 16.88 0.04 99.17 0.78 Sa 137 18.66 0.00 98.73 1.27 Sa 138 17.73 0.00 95.93 2.77 1.30 4.07 Sa 139 23.33 0.00 94.38 3.41 2.22 5.63 Sa 140 18.63 0.95 98.44 0.60 Sa 141 47.11 8.60 60.31 14.47 16.62 31,09 Clsa 142 24.61 0.03 98.87 0.79 0.31 1.10 Sa 1413 63.39 0.00 16.06 43.50 40.44 83.94 CISI 144 54.20 0.00 47.92 27.28 24.80 52.08 SaSICI 145 18.72 0.00 97.66 1.47 0.87 2.34 Sa 146 21.24 0.00 97.90 1.61 0,49 2.10 Sa 147 49.21 0.00 36.90 40.91 22.19 63.10 SaSiCl 148 19.35 1 0.00 99.89 0.11 Sa 149 20.83 0.22 99.45 0.34 Sa 150 19.53 0.00 99.59 0.41 Sa 151 31.36 0.0 0 82.53 9.45 8.02 17.47 Sa 152 16.45 0.07 99.77 0.16 Sa 14.91 1 8.67 89.25 1.38 1.38 S -.16.91 0.80 98.94 1 0.26 1 0.2-6 Sa 76 Station Water Textural Component Shepard's 4 Content (percent by weight) (1954) Gravel Sand Silt Clay Mud Class.* Si + Cl 155 30.50 0.00 85.19 8.07 6.74 14.81 Sa 156 24.70 0.00 89.73 6.49 3.78 10.27 Sa 157 1 18.92 0.00 99.69 0.31 0.31 Sa 158 19.76 0.71 98.98 0.31 1 0.31 Sa 159 17.89 2.73 97.21 0.07 0.07 Sa 160 14.17 0.18 99.63 0.19 0.19 Sa 161 20.31 0.00 95.14 2.96 1.90 4.86 Sa 162 40.85 0.00 58.87 22.21 18.92 41.13 SiSa 163 50.69 0.00 45.30 29.41 25.29 54.70 SaSICI 164 38.79 0.00 71.55 12.62 15.82 28.44 ClSa 165 19.59 0.00 99.59 0.41 0.41 1 Sa 166 13.96 1.31 98.63 0.06 0.06 Sa 167 13.84 0.34 99.60 0.06 0.06 Sa 168 16.06 0.05 99.57 0.38 0.38 Sa 16.9 15.37 0.11 99.87 0.02 0.02 1 Sa 170 17.14 0.69 99.29 0.02 0.02 Sa 171 1 62.17 1 0.00 1 3.16 1 56.53 40.32 96.85 Clsi 77 *,Key for sediment classification in Table based on Shepard's (1954) nomenclature: Sa = SAND S1 = SILT Cl = CLAY SaSi = SANDY SILT SiSa = SILTY SAND ClSa = CLAYEY SAND SaCl = SANDY CLAY SiCl = SILTY CLAY ClSi CLAYEY SILT SaSiCl SAND-SELT-CLAY 78 Table XIII. Chemical data for surficial sediment samples. BDL indicates below detection limit. Sta. Nitrogen I Carbon Sulfur Metal concentrations Percent by weight Cr Cu Fe Mn Ni Zn (ug/g) (ug/g) (0/.) (ug/g) (119/9) (129/9) 1 0.52 7.71 2.10 77.4 17.9 3.00 312.94 22.7 100.0 2 0.47 6.72 2.22 81.5 19.7 3.33 1 481.84 23.8 127.7 3 0.36 4.91 1.46 68.4 18.2 2.66 281.04 16.7 103.8 4 0.21 2.63 0.55 28.2 6.9 1.20 141.06 9.1 37.7 5 0.10 0.59 0.00 8.7 2.0 0.43 90.47 5.9 7.9 6 0.32 3.71 1.10 55.9 15.7 2.45 223.01 14.3 80.6 7 0.43 5.46 1.58 81.2 16.7 3.31 331.88 22.0 108.8 8 0.10 1.26 0.24 22.4 5.3 0.96 132.65 8.4 29.3 9 0.00-1 0.46 0.00 2.0 BDL 0.13 117.06 BDL 4.0 10 0.00 1.16 0.00 3.2 BDL 0.12 195.50 BDL BDL 11 0.45 5.94 1.61 86.2 17.6 3.47 383.80 24.2 125.9 12 0.45 5.83 1.68 77.8 13.5 3.24 381.10 24.1 103.8 13 0.35 4.08 0.87 58.5 10.3 2.44 248.07 17.0 75.6 14 0.31 3,21 1.00 69.1 12.9 2.93 299.06 21.6 95.5 15 0.17 1.63 0.34 39.6 6.2 1.62 214.78 10.4 54.2 16 0.16 1.3 0.22 37.6 6.3 1.46 224.68 13.7 49.1 17 0.38 4.56 1.41 86.4 35.3 3.44 268.79 31-.8 151.2 18 0.03 0.24 0.10 7.0 BDL 0.32 83.35 --BDL 7.9 19 0.42 5.24 1.70 78.0 15.1 3.31 370,43 24.1 112.7 20 0.43 5.30 2.26 85.2 17.4 3.61 322.68 22.2 134.8 21 0.37 5.42 2.04 96.2 18.7 4.02 413.93 27.3 144.5 22 0.40 5.09 1.86 84.6 16.7 3.21 305.40 19.7 137.1 0.19 3.81 0.86 42.7 4.5 3.76 364.07 10.1 44.3 79 Sta. Nitrogen I Carbon Sulfur Metal concentrations Percent by weight CT Cu Fe Mn Ni Zn (ug/g) (ug/g) (0/0) (ug/g) (ug/g) (ug/g) 24 0.24 3.67 1.11 68.1 10.7 2.92 288.87 16.2 95.5 25 1 0.44 5.60 1.19 1 76.5 15.3 2.93 334.24 19.4 1 108.3 26 0.26 4.22 1.36 73.6 12.9 3.15 309.04 19.5 104.9 27 0.09 1.02 0.19 18.6 2.5 0.87 135.74 4.1 25.1 28 0.17 1.84 0.54 48.0 7.9 1.98 248.20 12.9 65.2 29 0.09 0.65 0.11 18.4 2.8 0.76 114.82 7.0 24.0 30 0.03 0.22 0.00 4.4 BDL 0.17 44.61 BDL 3.1 31 0.00 0.25 0.04 6.2 BDL 0.29 63.80 BDL 6.4 32 0.24 3.46 1.23 70.0 11.5 2.78 289.91 21.0 98.0 33 0.04 0.66 0.15 14.9 BDL 0.74 141.29 6.3 19.1 34 0.04 0.51 0.12 13.2 BDL 0.65 133.04 3.0 16.7 35 0.01 0.45 0.08 11.1 1.4 0.47 103.87 3.7 10.7 36 0.16 2.02 0.65 55.4 12.6 2.30 261.09 -.17.0 77.6 38 --0.25 3.75 1.21 66.1 12.5 3.91 332.29 29.9 88.1 39, 0.25 3.58 1.20 82.9 15.0 3.54 385.80 22.5 117.5 40 0.15 2.65 0.96 76.4 13.0 2.76 306.35 19.3 99.3 41 0.08 1.32 0.47 35.7 5.5 1.54 196.61 7.1 44.4 42 0.05 1.09 0.31 31.6 4.7 1.26 180.09 9.0 41.5 43 0.29 0.46 0.13 17.7 1.8 0.68 102.47 3.9 22.5 44 0.00 0.15 0.05 6.2 BDL 0.24 64.30 BDL 5.3 45 0.09 .1.47 0.46 40.0 9.4 1.51 165.97 12.2 51.8 46 0.18 2.76 1.77 76.1 9.7 3.49 330.10 20.1 74.9 47 0.05 0.99 0.30 34.8 5.4 1.35 182.14 8.1 42.5 48 0.02 0.24 0.09 9.3 1.5 0.36 74.79 2.1 9.0 49 0.24 3.95 1.07 53.6 8.6 2.34 272.33 15.0 68.3 50 0.22 3.13 1.04 77.6 13.7 3.10 335.73 20.9 109.4 51 0.17 2.14 0.69 64.4 11.0 , 2.68 291.19 11.8 86.6 52 Sand sample- was not analyzed for chemistry 53 0.02 0.11 0.04 7.4 BDL 0.30 1 92.87 3.2 9.5 80 Sta. Nitrogen Carbon Sulfur Metal concentrations Percent by weight Cr Cu Fe Mn Ni Zn (ug/g) (ug/g) N (ug/g) (ug/g) (ug/9) 54 0.03 0.42 0.09 15.8 1.6 0.59 102.64 4.2 20.2 55 Sand sample- was not analyzed for chemistry 56.1 0.29 2.29 0.65 73.2 13.2 2.82 308.43 21.5 95.1 56.2 0.18 2.51 0.81 74.4 14.0 2.90 304.14 21.4 100.2 57 0.06 0.60 0.11 17.4 2.3 0.69 123.89 4.3 20.3 58 0.28 2.40 0.73 74.1 11.5 2.73 306.44 19.6 89.3 59 0.12 1.36 0.42 53.9 8.7 2.17 284.98 14.0 66.6 60 0.09 0.28 0.00 12.1 1.2 0.51 108.00 BDL 13.1 61 0.07 0.60 0.06 20.7 8.4 0.73 117-96 2.4 29.0 62 0.09 0.27 0.00 6.2 BDL 0.32 88.67 BDL 5.9 63 0.12 0.31 0.00 10.1 2.3 0.45 110.95 BDL 11.4 '64 0.28 2.85 0.39 28.4 7.7 1.06 162.43 6.0 39.7 65 0.11 0.19 0.00 5.9 BDL 0.29 64.40 BDL 7.6 66 0.06 0.18 0.00 10.1 BDL 0.58 157.38 3.5 1 67 0.08 0.67 0.01 21.4 3.2 0.87 135.05 4.3 27.1 68 0.20 2.37 0.83 80.1 13.2 2.87 315.16 20.0 96.3 69 0.08 0.17 0.00 5.4 BDL 0.34 88.92 BDL 7.0 70 0.31 3.81 1.20 73.6 11.9 2.86 282.10 21.3 97.4 71 0.35 5.53 1.63 71.1 13.7 2.90 .253.61 21.8 99.1 72 0.59 8.02 1.90 72.9 18.3 2.85 243-24 23.1 123.8 73 0.18 2.97 1.28 76.2 10.3 3.04 279.58 21.0 88.7 74 0.23 3.61 1.28 86.0 15.4 3.28 314.02 24.2 121.0 75 0.40 5.77 1.61 80.0 16.9 3.03 264.23 25.8 121.9 76 0.38 4.57 1.48 87.4 19.3 3.42 329-92 26.0 139.0 77 0.36 4.67 1-50 94.2 19.5 3.58 334.48 31.9 146.5 78 0.35 5.59 1.84 89.6 21.2 3.53 322.01 33.5 160.0 79 0.38 5.14 1.77 94.5 22.5 3.71 371 @58 35.1 163.1 80 0.47 6.11 2.15 100.3 25.1 3.85 357.48 35.8 187.7 81 F-0.5-0-T 7.79 2.38 86.4 26.4 3.36 294.60 29.3 173.6 81 Sta. Nitrogen I Carbon I Sulfur Metal concentrations Percent by weight Cr Cu Fe Mn Ni Zn (ug/g) (ug/g) (0/6) (ug/g) (ug/g) (ug/g) 82 0.59 7.80 2.52 94.6 27.2 3.61 315.33 30.5 193.9 83 0.59 9.86 3.10 77.5 30.9 3.31 238.30 29.4 235.0 84 0.56 7.91 3.16 97.3 32.2 3.69 289.09 32.2 214.2 85 0.25 4.48 1.67 92.5 19.4 3.43 308.11 27.7 133.0 86 0.30 4.24 1.62 101.9 22.2 3.59 329.02 11.1 125.8 87 0.04 2.74 1.31 87.4 17.7 3.29 306.51 28.5 122.2 88 0.11 2.65 1.08 91.0 16.9 3.32 313.51 26.1 123.0 89 0.13 2.66 1.05 86.3 15.3 3.23 311.78 28.3 112.8 90 0.07 2.22 1.07 68.4 11.6 2.61 267.67 20.1 92.4 91 0.16 2.35 0.87 72.6 15.2 2.95 297.83 22.6 99.0 92 0.00 0.42 0.18 21.6 3.2 0.88 118.62 4.6 29.6 93 0.09 1.84 0.83 71.4 11.1 2.98 318.95 16.7 88.2 94 0.25 3.82 1.43 90.8- 18.4 3.79 348.02 26.6 117.5 95 0.00 0.03 0.08 12.3 BDL 0.51 97.36 BDL - 12.6 96 0.07 0.43 0.21 32.6 3.7 1.38 226.85- 8.4 37.1 97 0.09 1.48 0.58 62.9 10.7 2.48 289.53 5.7 77.4 98 0.07 1.54 0.69 65.8 10.3 2.57 300.58 15.8 82.3 99 0.11 1.59 0.48 66.8 10.1 2.70 338.25 17.0 78.8 100 0.18 1.64 0.77 70.9 12.0 2.84 319.18 16.2 91.2 101 0.00 0.24 0.00 10.9 BDL 0.46 132.10 3.5 11.9 102 0.08 1.23 0.24 42.6 5.7 1.76 271.04 8.7 58.2 103 0.12 0.20 0.00 8.2 BDL 0.41 118.35 4.3 8.8 104 0.00 0.13 0.00 9.4- BDL 0.36 80.74 BDL 10.5 105 0.42 3.56 0:79 80.1 21.5 3.24 301.90 26.1 119.0 106 0.21 0.02 0.00 4.9 BDL 0.29 65.57 BDL 8.3 107 0.11 1 0.54 0.00 17.2 1.5 0.76 129.12 4.2 22.7 108 Sand sample- was not analyzed for chemistry 109 0.10 0.66 0.00 25.9 4.1 1.08 1 154.38 10.7 37.8 110 Sand sample- was not analyzed for chemistry 82 Sta. Nitrogen I Carbon I Sulfur Metal concentrations Percent by weight Cr Cu Fe Mn Ni Zn (ug/g) (ug/g) (0/.) (ug/g) (ug/g) (ug/g) 111 0.07 0.05 0.00 14.5 1.5 0.65 117.81 BDL 20.0 112 1 0.0 9 0.27 0.00 1 3.3 BDL 0.17 39.23 BDL 5.1 113 0.14 0.67 0.00 28.9 4.1 1.23 177.12 7.8 39.7 114 0.18 0.31 0.06 19.8 2.0 0.87 137.87 2.9 28.1 115 0.00 0.85 0.23 44.3 4.4 1.85 265.58 12.8 53.1 116 0.06 0.74 0.21 41.5 6.4 1.71 241.61 12.6 51.9 117 0.01 0.88 0.27 40.9 6.2 1.73 219.44 13.6 53.5 118 0.00 0.91 0.21 41.2 6.7 1.76 247.17 14.4 53.3 119 0.00 1.10 0.30 46.0 7.5 1.97 263.64 15.6 57.1 120 0.00 0.52 0.13 19.4 2.8 0.91 125.15 6.3 28.3 121 0.00 2.10 0.92 58.6 8.4 2.67 278.43 18.5 66-3 122 0.02 1.77 0.64 44@2 8.3 1.94 208.69 17.6 60.3 123 0.00 0.32 0.08 11.5 2.3 0.59 95.04 6.1 17.0 124 0.17 2.01 0.57 61.2 11.4 2.63 288.13 22.5 85.3 125 0.14 3.18 0.93 75.5 16.3 3.23 311.76 25.0 108.4 126 0.07 2.65 0.62 64.2 12.7 2.82 284.80 19.3 91.6 127 0.28. 3.30 0.98 73.6 16.8 3.15 296.94 24.1 118.5 128 0.22 3.85 1.21 84.7 20.1 3.47 328.51 24.0 139.9 129 0.10 1.11 0.30 41.3 7.1 1.73 246-52 13.2 53.6 130 0.10 1.09 0.29 36,6 6.8 1.54 211.99 10.6 41.8 131 0.02 0.18 0.11 12.8 BDL 0.61 100.17 7.8 18.0 132 0.03 0.35 0.13 15.7 11 0.75 111-93 8.8 23.7 133 0.10 1.45 0.62 40.8 6,5 1.81 230-64 16.5 54.4 134 0.00 0.15 0.00 6.0 BDL 0.38 103-22 5.2 9.0 135 0.05 0.07 0.00 5.7 BDL 0.36 97-85 4.5 8.2 136 0.10 0.11 0.00 4.4 BDL 0.30 78.91 5.3 7.4 137 0.00 0.10 0.00 3.7 BDL 0.24 61.23 3.1 6.3 q3 2 89 138 0.07 0.26 0.00 8.5 BDL 0.45 100-88 5.2 13.5 0.08 0.39 0.00 12.2 2.2 0.57 109-34 3.5 -r-I 6. 1 83 carbo Metal concentrations Sta. NitrogenF n I Sulfur Percent by weight Cr Cu Fe Mn Ni Zn (ug/g) (ug/g) C/-) (ug/g) (ug/g) (ug/g) 140 1 0.07 0.09 0.00 6.0 2.0 0.32 72.15 4.1 14.8 141 0.31 1.62 0.31 38.8 1 39.9 1.31 134.18 11.1 1 63.5 142 0.14 0.26 0.00 5.8 1.3 0.22 48.56 BDL 6.9 143 0.32 2.77 0.57 83.2 22.4 3.31 417.99 27.3 115.1 144 0.20 1.88 0.42 60.7 14.0 2.32 258.47 19.8 81.0 145 0.05 0.17 0.00 7.1 1.3 0.38 79.39 BDL 9.3 146 0.00 0.21 0.00 11.4 BDL 0.56 140.62. 3.8 13.5 147 0.24 1.94 0.50 55.1 12.6 2.11 230.36 15.7 75.0 148 0.00 0.02 0.00 5.6 BDL 0.32 101.62 BDL 4.6 149 0.00 0.09 0.00 2.3 1.2 0.13 32.41 BDL 2.1 150 0.00 0.15 0.00 4.9 BDL 0.28 83.67 3.1 6.5 151 0.07 0.17 22.4 4.3 0.93 127.01 6.3 30.7 152 Sand sample- was not analyzed for chemistry 153 0.00 0.14 0.00 3.9 1.6 0.24 77.61 BDL 5.1 154 0.00 0.02 0.00 17.6 6.2 0.78 126.23 6.6 23.7 155 0.05 0.64 0.00 24.3 4.6 1.04 7.9 31.6 156 0.11 0.54 0.00 19.2 5.1 0.81 1 127.14 1 4.6 f 24. 157 0.00 0.13 0.00 3.1 BDL 1 0.19 1 46.92 4.7 4.4 158 Sand sample- was not analyzed for chemistry 159 0.11 0.19 0.00 1.6 1.4 0.13 29.83 7.3 2.2 160 0.00 0.00 5.8 BDL 0.32 94.79 3.6 5.1 161 0.04 0.22 0.00 11.6 1.4 0.58 97.98 BDL 14.9 162 0.26 1.30 0.17 47.7 10.0 1.93 230.06 15.0 61.0 163 0.19 1.92 0.29 60.2 13.3 2.52 288.91 16.7 78.1 164 0.01 0.00 0.00 31.8 6.4 1.37 172.17 7.8 39.6 165 1 0.00 0.01 0.00 3.5 BDL 0.17 38.64 BDL 3.2 166 0.00 0.08 0.00 3.4 BDL 0.14 36.91 2.5 2.4 1.67 Sand sample- was not analyzed for chemistry 168 Sand sample- was not analyzed for chemistry 84 Sta. Nitrogen I Carbon I Sulfur Metal concentrations Percent by weight Cr Cu Fe Mn Ni Zn (ug/g) (ug/g) (%) (ug/g) (ug/g) (ug/g) 169 Sand sample- was not analyzed for chemistry 170 Sand sample- was not analyzed for chemistry 171 0.24 2.65 0.83 87.1 27.2 3.66 386.68 26. 85 Table XIV. Enrichment factors, relative to average continental crust, for metals analyzed in surficial sediments. Enrichment factors relative to average continental crust Station (Taylor, 1964) Cr Cu Mn NI Zn 1 1.45 0.61 0.62 0.57 2.68 2 1.38 0.61 0.86 0.54 3.08 3 1.45 0.70 0.63 0.47 3.14 4 1.33 0.59 0.70 0.57 2.54 5 1.14 0.47 1.25 1.03 1.48 6 1.29 0.66 0.54 0.44 2.65 7 1.38 0.52 0.59 0.50 2.64 8 1.32 0.57 0.82 0.66 2.46 9 0.88 5.29 2.48 10 1.56 10.02 11 1.40 0.52 0.65 0.52 2.92 12 1.35 0.43 0.70 0.56 2.58 13 1.35 0.43 0.60 0.52 2.50 14 1.37 0.47 0.63 0.57 2.71 15 1.38 0.40 0.79 0.48 2.70 16 1.45 0.44 0.91 0.70 2.70 17 1.41 1.05 0.46 0.69 3.54 18 1.25 1.57 2.01 19 1.33 0.47 0.66 0.55 2.74 20 1.33 0.49 0.53 0.46 3.00 1.35 1 0.48 1 0.61 0.51 1 2.89 22 1.48 0.53 0.56 0.46 3.43 86 Enrichment factors relative to average continental crust Statloh (Taylor, 1964) Cr Cu Mn Ni Zn 23 0.64 0.12 0.57 0.20 0.95 24 1.31 0.37 0.59 0.42 2.63 25 1.47 0.54 0.68 0.50 2.98 26 1.32 0.42 0.58 0.47 2.68 27 1.21 0.29 0.93 0.35 2.32 28 1.36 0.41 0.74 0.49 2.65 29 1.37 0.38 0.90 0.69 2.54 30 1.44 1.52 1.44 31 1.21 1.32 1.81 32 1.42 0.42 @0.62 0,57. 2.83 33 1.13 - A-1-2 -0.64-- 2.06 34 1.14 1.21 034 2.06 35 1.32---- 0.31- 1.3U----* ----0.-, 58 ----1.82 36 1.35 0.56 0.67 0.55 2.71 38 0.95 0.33 0.50 0.57 1.81 39 1.32 0.43 0.65 0.48 2.67 40 1.56 0.48 0.66 0.52 189 41 1.31 0.37 0.76 0.34 2.32 42 1.41 0.38 0.85 0.54 2.65 43 1.47 0.27 0.90 0,43 2.67 44 1.48 -1-.62- 1.90 45 1.50 0.64 0.65 0.61 2.77 46 1.23 0.28 0.56 0.43 1.73 47 1.45 0.41 0.80 0.45 2.53 4 1.45 0.41 1.22 0.43 1.99 49 1.29 0.38 0.69 0.48 2.35 87 Enrichment factors relative to average continental crust Station (Taylor, 1964) Cr Cu Mn Ni Zn 50 1.41 0.45 0.64 0.51 2.84 51 1.35 0.42 0.64 0.33 2.60 52 Sand sample- was not analyzed for chemistry 53 1.40 1.84 0.80 2.56 54 1.49 0.27 1.02 0.53 2.73 55 Sand sample- was not analyzed for chemistry 56.1 1.46 0.48 0.65 0.57 2.71 56.2 1.44 0.49 0.62 0.55 2.78 57 1.41 0.34 1.06 0.46 2.35 58 1.53 0.43 0.67 0.54 2.63 59 1.40 0.41 0.78 0.48 2.47 60 1.32 0.23 1.24 2.04 61 1.59 1.18 0.95 0.24 3.18 62 1.10 1.66 1.49 63 1.26 0.51 1.45 2.02 64 1.51 0.75 0.91 0.43 3.01 65 1.17 1.34 2.13 66 0.99 1.62 0.46 1.58 67 1.39 0.38 0.92 0.37 2.50 68 1.57 0.47 .0.65 0.52 2.70 69 0.90 1.55 1@65 70 1.45 0.42 0.58 0.56 2.74 71 1.38 0.49 0.52 0.56 2.75 72 1.44. 0.66 0.51 0.61 3.49 73 1.41 0.35 0.55 0.52 2.35 74 1.48 0.48 0.57 0.55 2.97 L I I 88 Enrichment factors relative to average continental crust Station (Taylor, 1964) Cr Cu Mn Ni Zn 75 1.49 0.57 0.52 0.64 3.24 76 1.44 0.58 0.57 0.57 3.27 77 1.48 0.56 0.55 0.67 3.29 78 1.43 0.62 0.54 0.71 3.65 79 1.43 0.62 0.59 0.71 3.54 80 1.47 0.67 0.55 0.70 3.93 81 1.45 0.81 0.52 0.66 4.16 82 1.47 0.77 0.52 0.63 4.32 83 1.32 0.96 0.43 0.67 5.72 84 1.48 0.89 0.46 0.66 4.67 85 1.52 0.58 0.53 0.61 3.12 86 1.60 0.63 0.54 0.23 2.82 87 1.50 0.55 0.55 0.65 2.99 88 1.54 0.52 0.56 0.59 2.98 89 1.50 0.49 0.57 0.66 2.81 90 1.47 0.45 0.61 0.58 2.84 91 1.39 0.53 0.60 0.58 2.70 92 1.37 0.37 0.80 0.39 2.69 93 1.35 0.38 0.63 0.42 2.38 94 1.35 0.50 0.54 0.53 2.50 95 1.36 1.14 1.99 96 1.33 0.27 0.97 0.45 2.16 97 1.43 0.44 0.69 0.17 2.51 98 1.44 0.41 0.69 0.46 2.58 99 1.39 0.38 0.74 0.47 2.35 100 1.41 0.43 0,67 0.43 2.59 89 Enrichment factors relative to average continental crust Station (Taylor, 1964) Cr CU Mn Ni Zn 101 1.33 1.71 0.57 2.09 102 1.36 0.33 0.91 0.37 2.65 103 1.13 1.71 0.78 1.73 104 1.46 1.32 2.33 105 1.39 0.68 0.55 0.61 2.96 106 0.97 1.36 2.33 107 1.28 1 0.20 1.01 0.42 2.42 108 Sand sample- was not analyzed for chemistry 109* 1.34---T 0.39 0.84 0.74 2.80 110 Sand sample- was not analyzed for chemistry 111 1.26 0.24 1.07- 2.47 112-. 1.07 1.34 2.39 113 1.33 0.34 0.85 0.48 2.60 114 1.28 0.23 0.94 0.25 2.60 115 1.34 0.24 0.85 0.52 2.31 116 1.37 0.38 0.84 0.55 2.44 117 1.33 0.37 0.75 0.59 1 2.48 118 1.32 0.39 0.83 0.61 2.44 119 1.31 0.39 0.79 0.59 2.33 120 1.20 0.32 0.82 0.52 2.50 121 1.24 0.32 0.62 0.52 2.00 122 1.28 0.44 0.64 0.68 2.50 123 1.09 0.39 0.95 0.78 2.31 124 1.31 0.44 0.65 0.64 2.61 125 1.31 0.52 0.57 0.58 2.70 126 1.28 0.46 0.60 1 0.51 2.61 90 Enrichment factors relative to average continental crust Station (Taylor, 1964) 9 Cr Cu Mn Ni Zn 127 1.31 0.55 0.56 0.57 3.02 128 1.38 0.59 0.56 0.52 3.25 129 1.35 0.42 0.85 0.58 2.49 130 1.34 0.45 0.81 0.52 2.18 131 1.18 0.97 0.95 2.37 132 1.18 0.28 0.89 0.88 2.55 133 1.27 0.36 0.75 0.68 2.42 134 0.88 1.60 1.02 1.89 135 0.91 1.63 0.94 1.85 136 0.82 1.54 1.31 1.95 137 0.87 1.51 0.96 2.10 138 1.07 1.33 0.87 2.41 139 1.21 0.41 1.15 0.46 2.29 140 1.05 0.64 1.33 0.96 3.71 141 1.67 3.13 0.61 0.64 3.91 142 1.49 0.60 1.32 2.53 143 1.42 0.69 0.75 0.62 2.80 144 1.47 0.62 0.66 0.64 2.81 145 1.06 0.34 1.24 1.98 146 1.13 1.48 0.51 1.92 147 1.47 0.61 0.65 0.56 2.86 148 0.98 1.89 1.17 149 1.03 0.96 1.53 1.33 150 0.97 1.76 0.82 1.85 151 1.36 0.47 0.81 1 0.51 1 2.67 Sand sample- was not analyzed for chemistry 91 Enrichment factors relative to average continental crust Station (Taylor, 1964) Cr Cu Mn Ni Zn 153 0.94 0.69 1.95 1.76 154 1.26 0.81 0.95 0.63 2.43 155 1.31 0.45 0.82 0.57 2.44 156 1.33 0.65 0.93 0.42 2.44 157 0.91 1.45 1.85 1.83 158 Sand sample- was not analyzed for chemistry 159 0.68 1.15 1.38 4.29 1.39 160 1.01 1.73 0.84 1.26 161 1.14 0.25 1.01 2.08 162 1.39 0.53 0.70 0.58 2.54 163 1.34 0.54 0.68 0.50 2.49 164 1.31 0.48 0.75 0.43 2.33 165 1.18 1.37 1.51 166 1.32 1 1 1.53 1 1.29 1.33 167 Sand sample- was not analyzed for chemistry 168 Sand sample- was not analyzed for chemistry 169 Sand sample- was not analyzed for chemistry 170 Sand sample- was not analyzed for chemistry 171 1 1.34 0.76 0.63 0.54 2.76 92 Table XV. Variation values for metal concentrations relative to background (or historical) levels. Variation values were calculated using equations 3 and 4 (see explanation in text). Variation from background levels Station (calculated using equations 3 and 4 - see text for explanation) Cr Cu Fe Mn NI Zn 1 -0.27 0.77 -0.36 -0.29 -0.30 0.28 2 -0.12 1.11 -0.18 0.24 -0.18 0.86 3 -0.05 1.27 -0.14 -0.10 -0.29 0.94 4 0.08 1.20 0.14 0.15 -0.05 0.87 5 0.03 0.51 0.67 0.81 0.36 0.08 6 -0.02 1.51 0.00 -0.10 -0.24 0.88 7 0.09 1.08 0.03 0.04 -0.09 0.96 8 0.04 0.91 0.14 0.26 0.00 0.73 9 -0.89 -0.82 0.22 -0.73 10 -0.42 -0.06 4.20 11 -0.05 0.89 -0.13 0.00 -0.16 0.87 12 -0.08 0.52 -0.12 0.06 -0.11 0.65 13 0.03 0.64 0.01 0.00 -0.10 0.78 14 -01.01 0.63 -0.06 -0.02 -O.Ot 0.83 15 0.16 0.57 0.14 0.38 -0.14 1.08 16 0.22 0.83 0.15 0.61 0.26 1.08 17 -0.24 2.31 -0.32 -0.43 -0.08 0.80 18 0.19 1.02 1.22 0.49 19 -0.07 0.71 -0.09 0.04 -0.10 0.81 20 -0.03 1 1.02 -0.06 -0.12 -0.19 1.08 21 -0.07 0.85 L_70.12 -0.04 -0.15 0.88 93 Variation from background levels Station (calculated using equations 3 and 4 see text for explanation) Cr Cu Fe Mn Ni Zn 22 -0.06 0.79 -0.19 -0.20 -0.31 1.04 23 -0.23 -0.31 0.61 0.48 -0.46 0.07 24 -0.05 0.34 -0.05 -0.07 -0.31 0.79 25 -0.01 0.91 -0.13 0.02 -0.21 0.88 26 -0.06 0.55 -0.08 -0.08 -0.22 0.80 27 -0.11 -0.03 0.06 0.34 -0.50 0.52 28 -0.01 0.40 -0.03 0.15 -0.22 0.79 29 -0.21 0.05 -0.18 0.05 -0.19 0.32 30 -0.59 -0.53 -0.24 -0.66 31 -0.58 -0.47 -0.13 -0.45 32 -0.05 0.46 -0.13 -0.09 -0.12 0.78 33 -0.24 -0.03 0.50 -0.16 0.23 34 -0.23 -0.01 0.57 -0.57 0.22 35 -0.38 -0.31 -0.32 0.20 -0.48 -0.25 36 0.08 1.35 0.05 0.18 0.01 1.02 38 -0.12 0.65 0.19 0.04 0.25 0.58 39 -0,04 0.65 -0.06 0.05 -0.18 0.83 40 0.01 0.56 -0.15 -0.06 -0.22 0.77 41 0.05 0.43 0.09 0.27 -0.41 0.71 42 0.01 0.33 -0.03 0.26 -0.19 0.72 43 -0.11 -0.21 -0.13 0.07 -0.49 0.43 44 -0.66 -0.67 -0.27 -0.64 45 0.18 1.53 0.07 0.09 0.04 1.01 46 0.09 0.28 0.16 0.10 -0.12 0.44 47 0.27 0.69 0.21 0.43 -0.19 1.00 48 -0.03 0.08 0.16 0.38 -0.55 0.10 94 Variation from background levels Station (calculated using equations 3 and 4 - see text for explanation) 4 Cr Cu Fe Mn Ni Zn 49 0.01 0.40 0.05 0.16 -0.16 0.72 50 0.07 0. /U -U.VI U.U / -U. 12 1.02 51 -0.02 0.49 -0.05 0.02 -0.46 0.76 52 Sand sample- was not analyzed for chemistry 0.11 0.69 1.18 -0.16 0.58 54 0.42 0.02 0.59 0.70 -0.17 1.19 55 Sand sample- was not analyzed for chemistry 56.1 0.06 0.72 -0.05 0.03 -0.05 0.85 56.2 0.02 0.74 -0.08 -0.03 -0.10 0.85 57 0.09 0.13 0.16 0.54 -0.35 0.58 0.07 0.49 -0.08 0.02 -0.14 0.73 59 0.19 0.62 0.15 0.41 -0.11 0.95 60 0.64 -0.02 1.48 1.37 1.00 61 0.40 3.51 0.34 0.57 -0.62 1.42 62 0.04 1.23 1.25 0.08 63 0.42 0.98 1.30 1.50 0.80 64 0.18 1.58 0.11 0.42 -0.34 1.12 65 0.06 1.23 0.68 0.44 66 0.64 2.75 2.87 -0-03 1.00 67 0.39 0.67 0.52 0.74 -0.32 1.18 68 0.12 0.72 -0.07 0.02 -0.14 0.80 69 -0.24 0.73 1.01 0.10 70 -0.06 0.40 -0.16 -0.16 -0.16 0.67 71 0.00 0.80 -0.06 -0.17 -0.06 0.86 72@ -0.16 1.06 -0.25 1 -0.34 -0.16 0.92 73 0.02 1 0.24 -0.06 -0.13 1 -0.14 0.59 95 Variation from background levels Station (calculated using equations 3 and 4 - see text for explanation) Cr CU Fe Mn NI Zn 74 -0.01 0.70 -0.14 -0. 15 -0.13 0.86 75 -0.09 0.85 -0.21 -0.29 -0.08 0.86 76 -0.06 1.05 -0.16 -0.16 -0.11 1.02 77 -0.03 1.02 -0.16 -0.18 0.05 1.03 78 -0.09 1.17 -0.19 -0.22 0.09 1.19 79 -0.06 1.30 -0.16 -0.11 0.13 1.20 80 -0.06 1.45 -0.19 -0.19 0.09 1.38 81 -0.17 1.65 -0.27 -0.32 -0.09 1.25 82 -0.19 1.52 -0.31 -0.34 -0.14 1.25 83 -0.18 2.37 -0.21 -0.40 0.00 2.34 84 -0.18 1.93 -0.30 -0.41 -0.11 1.44 85 0.02 1.12 -0.14 -0.19 -0.03 0.97 86 0.04 1.30 -0.17 -0.20 -0.63 0.73 87 0.01 0.98 -0.13 -0.16 0.04 0.90 88 0.05 0.88 -0.12 -0.14 -0.05 0.92 89 0.09 0.79 -0.06 -0.08 0.11 0.92 90 0.04 0.56 -0.07 -0.06 -0.07 0.88 91 0.01 0.91 -0.05 -0.04 -0.04 0.84 92 0.16 0.37 0.25 0.30 -0.38 1.02 93 0.01 0.39 -0.02 0.04 -0.28 0.68 94 -0.12 0.83 -0.17 -0.19 -0.17 0.54 95 0.22 0.55 0.72 0-48 96 0.16 0.02 0.22 0.70 -0.20 0.70 97 0.09 0.54 0.02 0.13 -0.71 0.79 8 0.05 0.40 1 -0.04 1 0.09 1 -0.25 1 0.75 99 0.07 0.39 0.01 0.23 -0.19 0.68 96 Variation from background levels Station (calculated using equations 3 and 4 - see text for explanation) Cr Cu Fe Mn Ni Zri 100 0.00 0.56 -0.08 0.04 -0.30 0.72 101 0.63 1.63 2.10 -0.09 0.98 102 0.06 0.30 0.04 0.51 -0.37 0.90 103 0.43 2.05 2.04 0.21 0.64 104 0.73 2.00 1.18 1.07 105 -0.08 1.47 -0.16 -0.18 -0.05 0.83 106 -0.09 1 1.35 0.75 0.62 107 0.51 -0.07 0.96 1.0 9 -0.1-9 1.41 108 Sand sample- was not analyzed for chemistry 109 0.11 0.50 0.17 0.40 0.23 1.08 110 Sand sample- was not analyzed for chemistry 111 1.64 0.54 4.29 2.13 2.87 112 -0.74 -0.61 -0.42 -0.50 113 0.28 0.49 0.37 0.64 -0.09 1.24 114 0.62 0.17 1.05 1.11 -0.47 1.79 If5 0.22 0.03 0.24 0.62 0.01 0.93 116 0.11 0.46 0.11 0.43 -0.04 0.83 117 0.06 0.37 0.08 0.26 0.00 0.83 118 0.14 0.60 0.17 0.51 0.14 0.93 119 0.04 0.37 0.08 0.32 0.01 0.71 120 -0.17 -0.11 -0.01 0.10 -0.31 0.55 121 -0.12 0.15 -0.08 -0.04 -0.15 0.32 122 -0.16 0.33 -0.12 -0.10 -0.02 0.53 123 -0.15 0.21 0.23 0.34 0.04 0.54 2 -0.12 0.49 -0.12 -0.04 -0.01 0.65 125 -0.13 0.80 -0.15 -0.16 -0.09 0.67 97 Variation from background levels Station (calculated using equations 3 and 4 - see text for explanation) Cr Cu Fe Mn NI Zn 126 -0.09 0.63 -0.08 -0.07 -0.16 0.73 127 -0.11 0.94 -0.12 -0.15 -0.09 0.93 128 -0.10 1.11 -0.17 -0.17 -0.19 0.99 129 0.35 0.98 0.38 0.75 0.21 1.28 130 0.15 0.88 0.19 0.46 -0.06 0.72 131 0.69 1.85 1.14 0.89 1.69 132 0.35 0.29 0.88 0.79 0.67 1.47 133 0.07 0.30 0.16 0.30 0.19 0.87 134 0.09 2.13 1.75 0.52 0.76 135 0.05 1.91 1.61 0.31 0.59 136 -0.18 1.50 1.11 0.56 0.44 137 -0.31 0.98 0.65 -0.09 0.23 138 0.01 0.76 1.03 0.21 0.84 139 0.20 0.56 0.70 0.93 -0.28 0.88 140 0.11 1.08 1.65 0.95 0.21 1.92 141 0.05 9.45 -0.16 -0.17 -0.10 1.27 142 -0.07 0.20 0.40 0.19 0.20 143 -0.02 1.63 -0.12 0.17 0.02 0.82 144 0.11 1.50 -0.01 0.10 0.11 0.98 145 -0-03 0.08 0.83 0.75 0.43 146 0.68 2.15 2.27 0.00 1.22 147 0.02 1.13 -0.08 -0.02 -0.12 0.85 148 0.02 1.60 1.70 -0.10 149 -0.58 0.21 0.03 -0.14 -0.59 -0.11 1.31 1.23 -0.10 0.26 151 0.04 0.71 0.09 0.24 -0.23 0.82 98 Variation from background levels Station (calculated using equations 3 and 4 - see text for explanation) NI _T Cr Cu J Fe Mn I Zn 152 Sand sample- was not analyzed for chemistry 153 -0.27 0.68 0.86 1.16 0.04 154 2.18 5.34 5.28 2.35 0.91 3.58 155 0.28 1.04 0.42 0.57 0.07 1.11 156 0.41 1.85 0.67 1 0.80 1 -0.22 1 1.23 157 -0.44 0.51 0.23 1 0.36 -0.16 158 Sand sample- was not analyzed for chemistry 159 -0.71 0.51 0.07 -0.19 1.19 -0.56 160 0.05 1.60 1.50 0.06 -0.02 161 0.22 0.04 0.90 0.82 0.84 162 0.10 1.19 0.05 0.21 0.03 0.86 163 0.08 1.29 0.05 0.20 -0.09 0.86 164 -0.10 0.74 -0.08 0.09 -0.36 0.47 165 -0.37 0.31 0.01 -0.40 166 -0.38 0.18 -0.01 -0.27 -0.54 167 Sand sample- was not analyzed fo r chemistry 168 Sand sample- was not analyzed for chemistry 169 Sand sample- was not analyzed for chemistry 170 Sand sample- was not analyzed for chemistry 171 1 -0.02 1.98 -0.05 0.03 -0.06 0.91 99 PRINTED BY THE DEPARTMENT OF GENERAL SERVICES GRAPHICS AND REPRODUCTION SERVICES ON RECYCLED PAPER 9 1 AARR 141()R .9500