Dataset: NOAA National Status and Trends "Biological effects of Toxic Contamination in Sediments from Long Island Sound and Environs"(Download Now)
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Detail view for dataset: NOAA National Status and Trends "Biological effects of Toxic Contamination in Sediments from Long Island Sound and Environs"

Region: Long Island Sound
Author: Douglas A. Wolf et al.
Sponsor: NOAA
Organization: National Ocean Service
Last Updated:
Organization: National Ocean Service

Intro:
Objective: Long Island Sound is one of several coastal regions selected for study under the Intensive Bioeffects monitoring surveys of NOAA's National Studies and Trends (NS&T) Program (Wolfe et al. 1993). With support from NOAA's Coastal Ocean Program, such intensive bioeffects surveys are conducted in areas where chemical data from the NS&T Program (or from related programs) indicate greatest potential for contaminant-related biological effects. The surveys have been conducted along postulated contaminant gradients: (1) to document the effects of contaminants on endemic feral organisms to contaminant gradients, and (2) to determine the areal extent of contaminant-related sediment toxicity. The surveys also provide a means for comparing different toxicity tests and testing promising new bioeffects indicators under operational field conditions (Long et al.1990a, Wolfe 1992, Wolfe et al. 1993). Sediment toxicity surveys gennerally provide finer resolution on the spatial distribution of potential contaminant effects than is possible from the responses in mobile feral organisms (Long et al. 1992, Wolfe et al. 1993).
Abstract: survey of sediment toxicity was carried out by NOAA's National Status and Trends Program in the coastal bays that surround Long Island Sound in New York and Connecticut. The survey objectives were to determine the spatial distribution and severity of toxicity, and to analize the relationships between toxicity and chemical contamination in the sediments. Sediment samples from three stations in each of 20 coastal bays and one Long Island Sound site were tested for toxicity with three independant protocols: 1) a 10-day amphipod survival test of the whole, solid-phase sediments with Ampelisca abdita, 2) a 48-hour exposure of clam larvae, Mulinia lateralis, to sediment elutriates, with normal development and survival as the endpoints, and 3) a microbial boiluminescence test (MicrotoxR) using solvent extracts of the sediments. Seperate samples from these same stations were analyzed chemically for a broad suite of potentially toxic contaminants, including heavy metals, polynuclear aromatic hydrocarbons (PAH), chlorinated pesticides and polychlorinated biphenyls. Additional sediment samples were obtained from up to six additional stations in a few of the coastal bays; these samples were examined only for heavy metals contamination and the data are included in an appendix to this report. The survey indicates that sediment toxicity is widespread in the coastal bays of Long Island Sound. Siginficant toxicity was indicated for the sediments from at least one of the stations in each of the 20 coastal bays sampled in this survey. Manhassett Bay, Oyster Bay and Little Neck Bay, New York were the three most toxic bays, repectively, as indicated by the concidence of significant toxicity in any of the three tests. Branford Harbor and the Connecticut River were indicated as the least toxic bays by this approach. About one-fifth of the total area (79.1 km2) sampled within the 20 embayments was indicated as significantly toxic by all three tests (survival of amphipods and larval bivalves, and MicrotoxTM). Although the observed toxicity tended to correlate with the contaminant levels in the sediments, the various contaminant classes covaried quite strongly with eachother and the toxicity therefore could not be readily atribited to any particular contaminant at any of the sampling locations. The concentrations of mercury and silver (and to a lesser extent lead, zinc and copper) most frequently exceeded levels commonly associated with toxicity in these samples. Among the organic contaminants, PAHs most frequently exceeded ER-M values, but chlorinated pesticides including DDT/DDE, chlordane and dieldrin often accompanied the PAH at levels exceeding ER-M values as well. Shifts in the strength of correlative relationships between toxicity and contaminant conentrations with and without normalization either to total organic carbon (TOC) or to the content of fine sediments further indicated that the observed toxicity was most likely due to organic contamination in the sediments. Cluster analysis and principle component analysis of these data demonstrated that the toxicity observed on these samples was strongly influenced not only by gross contaminant content, but also by intrinsic sample characteristics such as grain size and TOC content. These characteristics varied widely among stations within most of the bays in the sample set, and, coupled with the small number of samples in each bay, hindered the association of specific contaminants with toxicity for individial bays. The most contaminated bays based on numbers of ERM exceedances, however, were Little Neck Bay, Manhasset Bay, Pelham Bay, in New York, and Housatonic River in Connecticut. Except for Manhasset Bay, at least one sample from each of these bays showed exceedences of the ER-Ms for PAHs along with chlordane or dieldrin. manhasset Bay, by contrast, showed exceedences for a variety of chlorinated organic compounds. The ERM for mercury was also exceeded at all of the stations in three of these four bays, but not in any from the Housatonic River. Principle component analysis suggested that hexachlorobenzene might be associated with the toxicity observed at selected stations in Oyster bay, Centerport Harbor, and Larchmont Harbor, New York.
Collection method: Samples were talen using either a Smith-MacIntyre grab or a Van Veen grab, respectively. At each station, samples of surficial (1-3cm) sediments were taken from the grabs for the following analyses or tests: 1) acid-volatile sulfide (AVS) and simultaniously extracted metals (SEM); 2) inorganic and organic contaminants and total organic carbon (TOC); 3) grain size; and 4) sediment toxicity. Prior to each sample collection, the grabs and sampling scoops were cleaned by sucessive rinses with dichloromethane, acetone, and deionized water. For AVS/SEM analysis, surficial sediment was quickly removed (using teflon or Kynar-coated scoop) from three to five sectors of the grab sample placed in a100-mL wide-mouth glass with ateflon lined cap. The container was filled completely, sealed securely and stored on ice or refridgerated (not frozen) until shipment by overnight delivery to the analytical laboratory. After collection of the AVS/SEM sample, sediments were removed by the grab ( and from sucessive grabs) until approximately 5L of sediment had been accumucoated implement, and subsamples were taken for the other analyses. Samples for analysis of metals, organics and TOC were placed in a 500ml teflon jar and kept frozen until they were split and analyzed at the laboratory. samples for grain size analysis were placedin Whirl-pak bags, and those for toxicity testing (3.5L) were placed in polypropylene containers, stored immediately on ice and later refridgrated at 4 degrees celcius until testing. Subsamples for MicrotoxTM testing were seperated after the toxicity samples had been press sieved, and frozen until extraction. Amphipods were collected from the estuarine tidal flats of the Pettaquamscutt River in Narragansett Bay, RI. Surface sediments (down to ~ 10cm) were sieved (0.05mm mesh) and the amphipods were collected with a dip net, and transported to the laboratory where their taxonomic identification was confirmed. Prior to testing, the amphipods were held in presieved uncontaminated sediment from the collection site and fed, ad libitum, laboratory cultured diatoms Phaeodactylum tricornutum. Half the water in the holding container was replaced every other day, and the animals were acclimated to the essay temperature at the rate of 2 to 4 degrees Celcius per day.
Platform: Sampling was conducted from the NOAA ship Ferrel or from its 23-foot workboat.
Analysis method: Amphipod Tests: The ten day, whole sediment toxicity test with amphipods (Ampelisca abdita) was performed by Science Applications International Corporation (SAIC 1992) following published protocols (ASTM 1990a). Sediments were press seived through a 2.0mm mesh stainless steel screen, and if amphipods were present, through a 1.0mm mesh seive. Sediments (200mL) were then added to exposure containers (quart-size glass canning jars with an inverted glass dish as cover) and then covered with about 600mL filtered seawater. twenty subadult amphipods were distributed randomly into 100mL beakers containing 20 degree Celcius seawater, and these were then added to the test chambers. after 1 hr., non-burrowing amphipods were removed from the test chambers and replaced, and aeration was restarted. The animals were not fed during the 10-day tests, and lighting was continuous to inhibit swimming behavior. the number of dead or moribund animals on the sediment surface and the water surface was recored daily and dead animals were removed. Temperature was monitored daily, and salinity, dissolved oxygen, and pH were measured twice durring each test. at the end of the test, surviving amphipods were enumerated in the exposed chambers, and the data were entered into computer spreadsheets pending statistical analysis. Bivalve Larvae Tests: A 48-hr test of survivaland normal development of bivalve (Mulinia lateralis) embryos exposed to elutraites of test sediments was also conducted by SAIC (1992), following standard protocols (ASTM 1990b). Adult clams, offspring from a narragansett Bay population, were introduced through temprature manipulation to spawn. Eggs and sperm were collected and mixed in standard proportions. Fertilization was allowed to proceed for at least 35 minutes before separation of the embryo stock from the residual sperm. Percent fertilization and embryo density of approximately 1200 per mL were confirmed visually in subsamples. After homogenization, 100g (wet weight) portions of test sediments were placed into glass containers and refridgerated overnight, pior to addition of 500mL seawater (28-30 ppt) from the Narragansett Pier. The slurry was mixed by aeration and stirring for 30 minutes, and then allowed to settle for at least one hour prior to the filtration through a 0.4um cellulose nitrate filter in a polystyrene housing. Enought elutriate from each sample was filtered to produce five replicate samples of 15mL each. Approximately 900 Mulinia embryos (0.75mL well mixed stock suspenion) were added to each test vial, and the vials were incubated at 22 degrees celcius for 48 hrs. Embryo densities were reconfirmed by initial counts (6 replicates) performed during subsampling of the embryo stock suspension. Tests were terminated by addition of 0.75mL buffered formalin, and the numbrs and developmental stages of embryos were determined in 1mL susamples (after thorough mixing) for each vial. Percent survival in the test vials at the end of the exposure period was based on the mean initial embryo count. MicrotoxTM Tests: MicrotoxTM assays were performed on organic extracts of the test sediments (Schiewe et al. 1985). Sediment extractions and MicrotoxTM assays were performed by Parametrix, Inc. in Seattle, WA (SAIC 1992). On the day of extraction, frozen samples were thawed, excess water poured off, sediments were homogenized, and 3g (wet weight) samples were placed into 50mL centrifuge tubes (Teflon) for extraction. after 5 min centrifugation at 1900 rpm, aqueous layers were again discarded, and 15g anhydrous sodium sulfate and 30mL dichloromethane were added to each sample. Samples were tumbled end over end for 16 hours and centrifuged, and the extracts were decanted into amber glass bottles with Teflon-lined caps. This extraction process was repeated a second and third time with additional 30mL volumes of dicholromethane which were combined with the first, following tumbling and centrifugation each time. Half of the accumulated extract was then reduced to <5mL at 75 degrees Celcius in a jacketed Kuderna-Danish apparatus. Absolute ethanol (12.5 mL) was added, and the sample was again reduced to <5mL to completely eliminate dichloromethane, and the sample was brought to 5mL with ethanol and stored in a clean vial under nitrigen. MicrotoxTM assays were performed using a MicrotoxTM Model 500 instrument according to standard methods (Microbics 1992). Chemical Analyses: The suite of organic and inorganic chemicals measured in the sediment samples were those routinely measured by the NS&T Program, including polycyclic aromatic hydrocarbons (PAHs), DDT and its metabolites, cholorinated pesticides other than DDT, polychlorinated biphenyls (PCBs), and 16 trace and heavy metals (Robertson et al. 1993). Procedures for analysis of organic chemicals are outlined in MacLoed et al. (1985), Battelle Ocean Sciences (1991), and Lauenstein and Cantillo (1993). Briefly, PAHs PCBs and chlorinated pesticides are analyzed by electron capture gas chromatography or selective ion Gas Chromatography Mass Spectrometry. Methods for inorganic chemical analyses (total element) are described in Battelle Ocean Sciences (1991) Lauenstein and Cantillo (1993). Concentrations of different metals were determined either by cold vapor atomic absorption, hydride generation atomic absorbtion, graphite furnace atomic absorption, or inductively coupled plasma/mass spectrometry. Analyses for Acid-Volatile Sulfide (AVS) used selective generation of hydrogen sulfide, cryogenic trapping, gas chromatographic separation, and photoionization detection (Cutter and Oates 1987, Allen et al. 1991). following AVS analysis, the HCl digestate was filtered, and simultaneously extracted metals (SEM: cadmium, copper, lead, mercury, nickle, and zinc) were analyzed by flame atomic absorption. Total organic carbon content was determined using a LECO carbon analyzer after first removing inorganic carbon with 6N HCL. Grainsize was determined using standard seive and pipette method (Battelle Ocean Sciences 1992).
Quality control: Amphipod Tests: Control sediments were obtained from the Central Long Island Sound Reference Station prior to this study and stored frozen at SAIC. These sediments are fine-grained (>90% silt-clay) with about 2% total organic carbon, and have consistantly been non-toxic in solid phase tests with Ampelisca abdita. Tests were considered acceptable when control survival was atleast 90%. Bivalve Larvae Tests: tests were considered acceptable if at least 80% of the embryos introduced into seawater controls survived and at least 80% of the survivors showed normal development.
Quality assurance review:
Processing method: For each station, the amphipod and larval bivalve survival data (n=5) were arcsin-square root transformed, and compared using one-tailed, unpaired, t-tests to the respective controls to identify statistically significant differences (alpha 0.05). Based upon hundreds of toxicity tests with Ampelisca abdita and with bivalve larvae, a significant difference from controls is usually observed (i.e., in 90% of samples) when test survival is less than 80% of control survival. Similarly, statistical significance is nearly always observed in the MicrotoxTM test at test values of 70% or less of control values (G. B. Thursby, SAIC, personal communication). These values (80% and 70% of control values, for test organism survival amd MicrotoxTM response, respectively) are used in this repoet as separate criteria for significant toxicity, even though statistically significant differences were frequently detected at smaller differences from control values.
Data description: report, file discussed