Assessing the toxicity of freshwater sediments

Abstract

The science of sediment toxicology essentially began in the late 1970s. It was largely a product of dredging concerns and recognition of widespread contamination of sediments. During the past few years, sediment toxicity research activity has increased dramatically. Currently, most tests are of an acute nature with fewer available for determining sublethal endpoints of chronic toxicity. Test systems of single and multiple species have included most levels of biological organization in aquatic ecosystems and have been conducted in the laboratory on whole sediments, interstitial waters, elutriates, or other extractable fractions under a wide variety of conditions. Evaluations of methodological effects and comparisons with in situ toxicity using surrogate test species and indigenous communities have, on occasion, shown significant differences in test responses. These differences may be attributed to laboratory‐controlled parameters (e.g., light, species, life stage, exposure conditions, test phase, spiking method); sampling and laboratory‐induced disruption of sediment integrity; alteration of toxicant partitioning due to manipulations and temporal effects; and failure to recognize other influencing ecosystem variables (e.g., organism niche and life cycle, sediment partitioning and gradient dynamics, physicochemical and biological process integration, biotic and abiotic disturbances, micro‐ and macrobiota patches, food‐web interactions). Optimizing and standardizing test methods will require further studies of these variables to improve inter‐laboratory comparisons and ecosystem validity. Despite the many unknowns that exist, a variety of sediment toxicity tests have been effectively used in assessing toxicant contamination by measuring the bioavailable fraction of the in‐place pollutants. The optimal assays vary with the study and its objectives. Intergrative studies using several chemical, community, and toxicity measures are currently the most effective at defining ecosystem perturbations.

Toxicity analysis of freshwater and marine sediments with meio- and macrobenthic organisms: a review

“…Chapman & Fink, 1984 ;Fava et al ., 1985 ;Lydy et al ., 1990 ;McCauley et al ., 1992 ;Green et al ., 1993 ;West et al ., 1993) . Different strengths and weaknesses are associated with these procedures and some exposure modes may be appropriate in some cases but not in others (Burton, 1991 ;Ahlf, 1995) . Studies comparing the toxicity of metals in different exposure phases show that ions in overlying and pore-water are the main path of contamination for most benthic organisms, while the toxicity of sediment bound metal is negligible Phelps et al ., 1985 ;Nebeker et al ., 1986 ;Green et al ., 1993) .…”

“…Thus, the diagnosis of sediment quality should be centred around whole sediment analyses, with pore-water and elutriate tests only as complementary sources of information (Chapman & Fink, 1984 ;Ahlf, 1994) . Burton (1991) and Burton et al . (1992) evaluated the strengths and weaknesses of the different sediment toxicity exposure phases .…”

“…Catallo (1993) reviews the ecological effects of pollution in wetland ecosystems, including specific sections on benthic organisms . Perturbations in the benthos due to the toxic effect of introduced agents can be manifested at various levels, including molecules and cells, organisms, populations and communities, and whole ecosystems, in decreasing order of response sensitivity (Burton, 1991) . Most single-species tests of toxicity in sediments have focused on alterations within organisms (gross morphology, cells and molecules), their physiology, life history variables and behaviour .…”

“…(1992) . Meanwhile, a vast number of sediment toxicity tests have been made with benthic animals including field studies, laboratory tests and analyses of micro-and mesocosms (see reviews in Buikema & Cairns, 1980 ;Nebeker et al ., 1984 ;Chapman, 1986aChapman, , 1988Ahlf & Munawar, 1988 ;IJC, 1988 ;Giesy & Hoke, 1990 ;Burton, 1991 ;Burton et al ., 1992 ;Hamer et al ., 1992 ;Lamberson et al, 1992 ;Hill et al . 1993 ;Hooftman & Gimeno, 1993 ;Ahlf, 1994 ;US EPA 1994a, b ;and contributions in Burton, 1992) .…”

Effects of river sediment elutriates on Daphnia magna

“…A developing concern over the quality of sediments in waters under human impacts has resulted in rapid increase in sediment toxicity research (Burton, 1991) . A wide variety of bioassay techniques using organisms from microbes to macrophytes and fish have been applied to biological assessment of sediments .…”