A laboratory-formulated sediment incorporating synthetic acid-volatile sulfide
- IT Corp., Knoxville, TN (United States). Biotechnology Applications Center
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 > 80% in six of seven formulations with {le} 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 10-d H. azteca toxicity texts. 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.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 483692
- Journal Information:
- Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 12 Vol. 15; ISSN 0730-7268; ISSN ETOCDK
- Country of Publication:
- United States
- Language:
- English
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