Estimates of the Spatial Extent of Sediment Toxicity in Major U.S. Estuaries

Abstract

Acute laboratory toxicity tests were performed on surficial sediments collected from 1176 locations throughout 22 estuarine areas in the United States. Toxicity was determined with three standardized procedures: 10-day amphipod survival tests with solid-phase (bulk) sediments; 5-min microbial bioluminescence tests with organic solvent extracts of the sediments; and either 1-h sea urchin fertilization tests or 48-h mollusc embryo tests with the porewater of the sediments. Test results were weighted to the sizes (km2) of the geographic strata in which samples were collected. Selected bays and estuaries were sampled along the Atlantic and Gulf of Mexico coasts and in southern California along the Pacific coast of the United States. The individual survey areas ranged in size from <1.0 km2 to over 550 km2. Col lectively, approximately 2532 km2 were sampled in the 22 surveys. Toxicity was observed in the amphipod survival tests of bulk sediments in approximately 10.9% of the combined area. These data suggest that acute toxicity as measured with adult crustaceans was restricted to small portions of these urbanized estuaries, principally maritime harbors and industrial ized bayous and waterways. Toxicity was much more pervasive in the tests of solvent extracts and 100% porewater, indicating that approximately 61% and 43%, respectively, of the combined areas sampled were toxic. The spatial extent of toxicity decreased to 11% and 5% in tests of 50% and 25% porewater, respectively. In most areas each test indicated different patterns in toxicity, and consequently, the concordance in estimates of toxicity among different tests was very small. Estimates of the spatial extent of toxicity probably would differ if tests were performed elsewhere and/or with different organisms.

Revision of sediment quality triad indicators in Puget Sound (Washington, USA): I. a Sediment Chemistry Index and targets for mixtures of toxicants

“…This definition of toxicity has been used nationwide by both NOAA (Long et al 1996) and the United States Environmental Protection Agency (USEPA) (2006) and used throughout all of Puget Sound . Samples were defined as toxic in the HRGS assay if the mean response was significantly greater than the negative control and greater than the 90% upper prediction limit of 37.1 mg benzo[a]pyrene/g (i.e., mgB[a]p/g).…”

Comparison of porewater and elutriate bivalve larval development toxicity testing in a sediment quality triad framework

“…Summers (2001) concluded that nearly 30% of the total US estuarine area displayed poorer than expected biological condition, based on sediment toxicity, benthic and fish community composition and fish pathology, while Long et al (1996) found that nearly 11% of the total area (277 km2 of 2532 krn2) of 22 major US estuaries exhibited significant acute toxicity to amphipods. Local waterbodies demonstrate similar patterns-for example, PSAMP (2002) concluded that 63% of the total area of Puget Sound was degraded, based on sediment chemistry, toxicity and benthic community structure.…”

“…Carr et al (1996a) stated that porewater tests using sea urchins were considerably more sensitive than sediment amphipod testing, based on an evaluation of sediment toxicity in the vicinity of offshore oil & gas platforms. Long et al (1996) found that tests involving the effects of 100% porewater on sea urchin fertilization (Arbacia punctulata), or sea urchidabalone larval development (Strongylocentrotus purpuratus, Haliotis rufescens) led to the determination that 43% of the total area in major US estuaries was toxic, while tests involving the effects of whole sediment amphipod survival led to the determination that only 11% of the total area was toxic. Porewater toxicity testing, therefore, was considered more sensitive than amphipod toxicity testing on whole sediment.…”

“…Conversely, little evidence was provided by Long et al (1996) to demonstrate increased sensitivity of porewater concentrations. Ammonia was not evaluated as a potential cause for the observed porewater toxicity in Long et al (1996), making it likely that many of the samples categorized as "toxic" were in fact influenced by ammonia toxicity.…”

Mechanistic sediment quality guidelines based on contaminant bioavailability: Equilibrium partitioning sediment benchmarks

“…According to some surveys conducted in the United States, the quantities approach billions of metric tons of sediment representing potentially significant ecological and human health risks [4][5][6]. Furthermore, extensive surveys of these sediments have shown many to be toxic to benthic marine organisms [11,12]. Estimated costs associated with managing these sediments in terms of remediation (e.g., dredging and capping) and postoperational monitoring are in the billions of U.S. dollars [13].…”