Procedures are described for testing freshwater organisms in the laboratory to evaluate the toxicity or bioaccumulation of contaminants associated with whole sediments. Sediments may be collected from the field or spiked with compounds in the laboratory. Toxicity methods are outlined for two organisms, the amphipod Hyalella azteca and the midge Chironomus tentans. The toxicity tests are conducted for 10d in 300-mL chambers containing 100 mL of sediment and 175 mL of overlying water. Overlying water is renewed daily and test organisms are fed during the toxicity tests. The endpoint in the toxicity test with H. azteca is survival and the endpoints in the toxicity test with C. tentans are survival and growth. Procedures are primarily described for testing freshwater sediments; however, estuarine sediments (up to 15% salinity) can also be tested with H. azteca. Guidance for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus is provided in this manual. Overlying water is renewed daily and test organisms are not fed during bioaccumulation tests. Methods are also described for determining bioaccumulation kinetics of different classes of compounds during 28-d exposures with L. variegatus.

Methods for measuring the toxicity and bioaccumulation of sediment-associated contaminants with freshwater invertebrates

A review of approaches for classifying benthic habitats and evaluating habitat quality.

Historic and ongoing sediment contamination adversely affects estuaries, among the most productive marine ecosystems in the world. However, all estuaries are not the same, and estuarine sediments cannot be treated as either fresh or marine sediments or properly assessed without understanding both seasonal and spatial estuarine variability and processes, which are reviewed. Estuaries are physicochemically unique, primarily because of their variable salinity but also because of their strong gradients in other parameters, such as temperature, pH, dissolved oxygen, redox potential, and amount and composition of particles. Salinity (overlying and interstitial) varies spatially (laterally, vertically) and temporally and is the controlling factor for partitioning of contaminants between sediments and overlying or interstitial water. Salinity also controls the distribution and types of estuarine biota. Benthic infauna are affected by interstitial salinities that can be very different than overlying salinities, resulting in large-scale seasonal species shifts in salt wedge estuaries. There are fewer estuarine species than fresh or marine species (the paradox of brackish water). Chemical, toxicological, and community-level assessment techniques for estuarine sediment are reviewed and assessed, including chemistry (grain size effects, background enrichment, bioavailability, sediment quality values, interstitial water chemistry), biological surveys, and whole sediment toxicity testing (single-species tests, potential confounding factors, community level tests, laboratory-to-field comparisons). Based on this review, there is a clear need to tailor such assessment techniques specifically for estuarine environments. For instance, bioavailability models including equilibrium partitioning may have little applicability to estuarine sediments, appropriate reference comparisons are difficult in biological surveys, and there are too few full-gradient estuarine sediment toxicity tests available. Specific recommendations are made to address these and other issues.

https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.5620200102

Assessing sediment contamination in estuaries.

Pacific herring eggs were exposed for 16 d to weathered Alaska North Slope crude oil. Exposure to an initial aqueous concentration of 0.7 parts per billion (ppb) polynuclear aromatic hydrocarbons (PAHs) caused malformations, genetic damage, mortality, and decreased size and inhibited swimming. Total aqueous PAH concentrations as low as 0.4 ppb caused sublethal responses such as yolk sac edema and immaturity consistent with premature hatching. Responses to less weathered oil, which had relatively lower proportions of high molecular weight PAH, generally paralleled those of more weathered oil, but lowest observed effective concentrations (LOECs) were higher (9.1 ppb), demonstrating the importance of composition. The LOEC for more weathered oil (0.4 ppb) was similar to that observed in pink salmon (1.0 ppb), a species with a very different development rate; by inference, other species may be similarly sensitive to weathered oil. Our methods simulated conditions observed in Prince William Sound (PWS) following the Exxon Valdezoil (EVO) spill. Biological effects were identical to those observed in embryolarval herring from PWS in 1989 and support the conclusion that EVO caused significant damage to herring in PWS. Previous demonstration by our laboratory that most malformed or precocious larvae die corroborates the decreased larval production measured after the spill. Keywords—Herring larvae Morphological damage Genetic damage Polynuclear aromatic hydrocarbons Exxon Valdez oil spill

/pdf/sensitivity-of-fish-embryos-to-weathered-crude-oil-part-i-38cftd6woo.pdf

Sensitivity of fish embryos to weathered crude oil: Part I. Low‐level exposure during incubation causes malformations, genetic damage, and mortality in larval pacific herring (Clupea pallasi)

Tens of thousands of synthetic substances are in existence today and hundreds of new compounds are being introduced every year. Because of the complexity of the physico-chemical interactions between pollutants and the marine environment, the potential toxicity of contaminants can be assessed adequately only by means of bioassays with living organisms. From a practical point of view, a bioassay needs to be sensitive and scientifically valid, yield rapid results at moderate cost, and the organism in question must be readily available.

Ecotoxicological bioassays with bivalve embryos and larvae fulfil these criteria better than most other tests. They have increasingly come into use during the past three decades and are now commonly employed to ascertain the biological effects of pure chemicals, as well as to determine the quality of effluents, coastal waters and sediments sampled in the field. There do not appear to be very great differences between bivalve species with regard to larval sensitivity to toxicants. The principal species for bioassays are oysters (Crassostrea gigas and C. virginica), and mussels (Mytilus edulis and M. galloprovincialis).

Bioassays are conducted with gametes and larvae of ail ages: sperm and unfertilized eggs, embryos, young D-larvae, intermediate umboned larvae, and pediveligers towards the end ofthe pelagic period. Embryos are usually the most sensitive stage. Recent advances now also permit bioassays on metamorphosing pediveligers, a method particularly suited to investigate the effects of adsorbate-contaminated surfaces. There are various criteria for the assessment oftoxic effects, including embryogenesis success (abnormalities), larval growth, mortality, physiology (e.g. feeding or swimming activity), and metamorphosis success.

Chronic toxicity studies may be carried out over periods ofseveral weeks, but larval rearing in the laboratory requires considerable effort (e.g. cultivation of algal food). The method of choice for investigations of acute toxicity and for routine monitoring studies is the embryo bioassay because it is very sensitive, relatively simple, and produces results within 24 or 48 hours. The data obtained by different investigators are often difficult to compare, however, because of differences in methodology. There is no firmly established procedure, and further simplification and standardization of techniques is required.

In bioassays with a single pollutant, the effective toxic concentration may span several orders of magnitude, depending on bioassay procedures, larval stage and choice of response. Tributyl-tin (TBT) is the most toxic compound ever bioassayed with bivalve larvae, with effective concentrations (EC50) as low as a few nanograms per litre (i.e. 10−3 ppb). Heavy metals (particularly mercury, silver and copper) are next in order of toxicity, with EC50 values between a few micrograms per litre (ppb) and several hundred ppb. Chlorine and some organochlorine pesticides may also have EC50 values of less than 100 ppb, while detergents and petroleum products are generally less toxic

The Assessment of Marine Pollution - Bioassays with Bivalve Embryos and Larvae

The relative sensitivity, analytical precision, discriminatory power and concordance among endpoints and with sediment chemistry were compared among five sediment toxicity tests. The tests were performed with aliquots of 15 composited, homogenized sediment samples. Survival and a variety of sublethal endpoints were determined in tests performed with the amphipods Rhepoxynius abronius and Ampelisca abdita, embryos of the mussel Mytilus edulis, embryos of the urchin Strongylocentrotus purpuratus, and the polychaete Dinophilus gyrociliatus. Each sample was also tested for trace metal and organic compound concentrations, organic carbon content and texture. Two of the five tests (survival among M. edulis and survival among R. abronius) were highly sensitive to the samples and had relatively high precision, but the results were correlated most highly with sedimentological variables. One of the tests (survival among A. abdita) was relatively insensitive, but the results were highly correlated with only the concentrations of toxic chemicals. The test with S. purpuratus indicated mutagenicity in several samples that had high hydrocarbon concentrations. The test of pore water with D. gyrociliatus was intermediate in sensitivity and precision and not correlated highly with the results from the other tests.

Comparative evaluation of five toxicity tests with sediments from san francisco bay and tomales bay, california

Estuarine and marine amphipods have been chosen by the U.S. Environmental Protection Agency (EPA) for use in standardized 10-d sediment toxicity tests. An interlaboratory comparison (round robin) was conducted to evaluate the precision of these methods. This comparison included three species, Ampelisca abdita, Eohaustorius estuarius, and Leptocheirus plumulosus. Each species was exposed for 10 d under static, nonrenewal conditions to four sediment treatments using standardized, species-specific test protocols by at least six independent facilities. Sediment treatments were selected for each species to include one negative control sediment and three contaminated sediments. Highly contaminated sediment from Black Rock Harbor (BRH), Connecticut, was diluted with species-specific, noncontaminated control sediment, creating test sediments that ranged in relative contamination from low to high. Laboratories showed strong, logical agreement in rank survival for all species, with control sediment consistently exhibiting the highest survival, and sediment with the greatest proportion of BRH consistently exhibiting the lowest survival. Although instances of considerable interlaboratory variability occurred, laboratories showed acceptable survival and variability in control sediments, significant agreement in ranking sediment toxicity, and agreement in the categorization of sediments as toxic or nontoxic for all three species.

Interlaboratory comparison of a 10-day sediment toxicity test method using Ampelisca Abdita, Eohaustorius Estuarius and Leptocheirus Plumulosus

SUMMARY The Chesapeake Bay Benthic Index of Biotic Integrity (B-IBI) and the Environmental Monitoring and Assessment Program’s Virginian Province Benthic Index (EMAP-VP BI) were applied to 294 sampling events in Chesapeake Bay and the results were compared. These estuarine benthic indices are intended to identify benthic invertebrate assemblages that have been degraded by low dissolved oxygen concentrations or high concentrations of chemical contaminants. The B-IBI includes several community measures and weights them equally using a simple scoring system that compares them against values expected for undegraded sites. It includes 11 measures of species diversity, productivity, indicator species and trophic composition. The EMAP-VP BI uses discriminant function coefficients to weight contributions of species diversity and the abundances of two indicator families. The two indices agreed on degraded or undegraded classifications for benthos at 81.3% of the sites. This level of agreement is within the level of accuracy achieved during index development and, therefore, may approach the limits that can be achieved. The indices were strongly associated (Pearson’s r ¼ 0.75). The B-IBI was more conservative than the EMAP-VP BI, classifying 72.7% of the disagreements as degraded. The 55 sites where the indices disagreed were distributed in different habitats throughout the Bay except polyhaline sand. Many of the classification disagreements were at sites with index values close to, but on opposite sides of, the degraded–undegraded thresholds, with 49.1% of the B-IBI values within 0.5 units and 81.8% within 1.0 units; the corresponding values for sites where both indices agreed were only 23.4% and 62.7%, respectively. The pattern for the EMAP-VP BI was similar, with 61.8% and 74.6% of disagreements and only 18.8% and 38.9% of agreements within 0.5 and 1.0 units of the threshold. Although the close agreement suggests that either index is suitable for evaluating the benthic condition, the B-IBI offers some additional advantages. Copyright # 2002 John Wiley & Sons, Ltd.

John Scott

Papers

Comparative evaluation of five toxicity tests with sediments from san francisco bay and tomales bay, california

Interlaboratory comparison of a 10-day sediment toxicity test method using Ampelisca Abdita, Eohaustorius Estuarius and Leptocheirus Plumulosus

Application of two indices of benthic community condition in Chesapeake Bay