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A laboratory‐formulated sediment incorporating synthetic acid‐volatile sulfide
Author(s) -
Gonzalez Adrian M.
Publication year - 1996
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620151215
Subject(s) - sulfide , chemistry , environmental chemistry , hyalella azteca , sediment , metal , metal toxicity , toxicity , nuclear chemistry , amphipoda , organic chemistry , ecology , geology , biology , heavy metals , paleontology , crustacean
The application of laboratory‐formulated sediment (LFS) could be expanded if toxicologically significant characteristics of sediment other than particle‐size distribution, organic carbon content, and pH could be manipulated. This report describes the preparation of a LFS containing synthetic acid‐volatile sulfide (AVS) and shows its similarity to natural sediment AVS. Several formulations were evaluated with respect to toxicity to Hyalella azteca and chemical stability. Amphipod survival was highest (95%) in LFS formulations in which the molar iron(II)/sulfide ratio was near 1, although amphipod survival was >l80% in six of seven formulations with ≤20% excess metal or sulfide. Synthetic AVS in the test system oxidized rapidly at the sediment surface, but AVS at depth was stable for >30 d when isolated from air or aerated water. Oxidation‐reduction potential measurements and AVS analysis of core slices revealed a vertical oxidation profile, apparently established and limited by oxygen diffusion. A formulation consisting of a 1:1 molar ratio of iron and sulfide (FeS) was evaluated with respect to complexation of copper, zinc, and nickel and to the corresponding reduction in toxicity using W‐AH. azteca toxicity tests. Amphipod mortality in metal‐spiked LFS with metal/AVS molar ratios >1 was high relative to controls. In contrast, amphipod survival in metal‐spiked LFS with metal/AVS molar ratios >1 was generally similar to amphipod survival in nonspiked LFS containing synthetic AVS. A few exceptions, where toxicity was noted when metal/AVS ratios were <1, could be explained by high concentrations of dissolved iron, which was released by the metal + AVS displacement reaction. The LFS containing synthetic AVS appears to mimic natural sediment AVS and thus can provide consistent and controlled substrates suitable for investigating metal/sediment chemistry and toxicity and for developing realistic sediment quality criteria for metals.