Addition of contaminant bioavailability and species susceptibility to a sediment toxicity assessment: Application in an urban stream in China

Residue Analysis of Organochlorine and Organophosphorus Pesticides in Urban Lake Sediments

“…Point P5 presented 33% of the total disulfoton samples with significant potential for adverse effect. Among the OP pesticides, the most researched is the chlorpyrifos, present in studies conducted by Weston et al (2013), Li et al (2013), Hunt et al (2016), Nowell et al (2016), andXu et al (2016). In our study, chlorpyrifos was identified in only one sample (4,174 ng g −1 ), with a risk coefficient of 1.003, indicating a small potential for adverse effects.…”

Integrated sediment quality assessment through biomarker responses and bioavailability measurements: Application in Tai Lake, China

“…Bulk sediment concentrations may overestimate sediment toxicity and cause misidentification of the causative agents of the observed toxicity due to different bioavailability of sediment-bound chemicals (Cornelissen et al, 2001). Recent studies demonstrated that sediment toxicity was better explained by bioavailability-based dose metrics than traditional TUs estimated from bulk sediment concentrations (You et al, 2008;Li et al, 2013;Lydy et al, 2015). To improve the accuracy in identifying putative toxicants in sediment, the bioavailability of PAHs, OCPs and OPs were measured using a 24-h Tenax extraction.…”

From Incorporation to Toxicity

“…Indirect determination of bioavailability through the assessment of toxicological parameters (median lethal concentrations [LC 50 ], median effect concentrations) has been proposed for pyrethroid insecticides (Xu et al, 2007;Harwood et al, 2013;Li et al, 2013). Expressing the LC 50 s for C. tentans in different sediments with regard to insecticide concentrations on a bulk sediment basis, organic carbon-normalized sediment basis, porewater basis, dissolved organic carbon-normalized porewater basis, and freely dissolved porewater basis has shown that the latter was the most representative of the bioaccessible fraction (Xu et al, 2007).…”

“…Expressing the LC 50 s for C. tentans in different sediments with regard to insecticide concentrations on a bulk sediment basis, organic carbon-normalized sediment basis, porewater basis, dissolved organic carbon-normalized porewater basis, and freely dissolved porewater basis has shown that the latter was the most representative of the bioaccessible fraction (Xu et al, 2007). SPME fibers and Tenax beads allow a more accurate assessment of toxicity across sediment types than those based on total sediment concentrations of pyrethroid insecticides (Harwood et al, 2013;Li et al, 2013). Similarly, free aqueous PCB concentrations or surrogate measures such as the PCB concentration assimilated by passive samplers (for example, single-phase polyoxymethylene or SPME), or the Tenax extractable PCB concentration, correlate better with biolipid concentrations than relationships based only on total organic carbon normalized solid-phase concentrations (Werner et al, 2010).…”