In situ simulation of thin-layer dredging effects on sediment metal release across the sediment-water interface

摘要: Dredging is widely applied to remediate contaminated sediments in aquatic ecosystems. However, the efficiency of thin-layer dredging for metal pollution control remains uncertain and even controversial. This study conducted an in-situ simulation experiment Lake Taihu investigate effects on sediment release based fractions, diffusion flux kinetics parameters resupply, using diffusive gradient thin films (DGT), multi-microelectrode, European Community Bureau Reference (BCR) sequential extraction scheme. Results indicated that exchange fluxes metals did not necessarily correspond total concentrations or contents different sequentially-extracted fractions; there were appreciable decreases Ni, Cd, Cu Zn terms whereas bioavailability labile (but Cd) all notably promoted (by 136, 128 149%, respectively) dredged area compared those un-dredged sediments. Further analysis resupply by DGT technique DGT-induced model (DIFS) showed higher metals, with a larger ability from after dredging. Therefore, had possibility increase water column. was attributed remobilization sulfides anoxic deep sediments, as oxidation increased due introduction oxygenated water, causing subsequent dissolution sulfide-bound metals. In conclusion, may mitigate contamination, although it can reduce load. Our findings dual provided new insights into mechanism induced