Mercury Bioavailability in Fluvial Sediments Estimated Using Chironomus riparius and Diffusive Gradients in Thin-Films (DGT)

Mercury bioavailability was assessed by exposing the dipteran Chironomus riparius for whole life cycle to legacy-contaminated fluvial sediments (0.038–0.285 mg Hg kg−1 d.w.) and analyzing tissue concentrations in larvae at different exposure times (7, 11, 16 days) adults. In same experiment, diffusive gradients thin-film passive samplers (DGTs), both piston- probe-shaped, were co-deployed retrieved as organisms. To compare two approaches, results showed a good agreement between accumulation kinetics of C. DGTs, approximating an apparent steady-state. A strong correlation found values tissues types DGTs (r 0.74 0.99). Concentrations mature (19–140 µg w.w.), which may represent basal level aquatic food web, exceeded European Environmental Quality Standard biota (20 aims protecting top predators from secondary poisoning. Body burdens adults similar, showing negligible decontamination during metamorphosis proving efficient mercury transfer terrestrial webs.