John Wiley & Sons, Ltd.

Improving sediment quality guidelines for nickel: Development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments

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Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel‐spiked sediments, including one 'reasonable worst‐case' (RWC) sediment with low concentrations of acid volatile sulfide (AVS) and total organic carbon (TOC). The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea) and midges (Chironumus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel spiked sediments. A species sensitivity distribution (SSD) was elaborated based on 10% effect concentrations (EC10s) yielding a threshold value of 94 mg Ni/ kg dry weight under RWC conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (EC20s) and AVS and Fe, and these models were used to derive site‐specific sediment quality guidelines (SQGs). Normalization of toxicity values reduced the inter‐sediment variability in toxicity values significantly for the amphipod species, H. azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126–281 mg Ni/kg dry weight, based on the AVS model and 143–265 mg Ni/kg dry weight, based on the Fe model. Environ Toxicol Chem © 2013 SETAC

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