Sediment pollution has been an important environmental issue for decades. When contaminants, especially heavy metals, enter aquatic environments such as rivers, lakes or ocean, most metals would settle down with water matrices (e.g., dissolved matters or suspended particles) into sediment. If the polluted sediment is disturbed or changed its chemical condition, the sediment heavy metals could be released to  the water column again.<br/>Copper (Cu) is a commonly detected sediment contaminants, and its concentration can reach to hundreds to thousands mg/L in sediment. Aquatic organisms are very sensitive to Cu ion, which at μg/L level can cause lethal effect to some species. In this study, we aim to investigate the dissolution, mobility and bioavailability of different Cu-contaminated environmental sediments and their association to toxicity using a whole sediment exposure strategy with embryos of medaka fish (<i>Oryzias latipes</i>) as a model organism. The Cu ion in overlying and pore water and Cu speciation in sediment were quantified with filtration, Chelex 100 or sequential extraction, respectively. The correlation of Cu bioaccumulation in treated embryos with sediment properties and different Cu species was performed to understand bioavailability and subsequent bioaccumulation of Cu from sediment to embryos. Our results demonstrated that sediment with lower levels of pH values, cation exchange capacity or organic matter tended to release Cu ion in pore and overlaying water, thus causing higher copper bioavailability (e.g., copper accumulation in embryos) and toxicity (e.g., embryos mortality). Either dissolved Cu in overlaying water and pore water or Chelex 100 extractable Cu showed a good correlation with Cu bioaccumulation and embryos mortality. Our results demonstrated that the established embryos exposure system can successfully assess the copper bioavailability and toxicity from sediment exposures.<br/>

Using medaka embryos coupled with a whole sediment exposure strategy to assess copper bioavailability and toxicity in sediment

254th National Meeting (2017)

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