The role of shelf mud depositional process and large river inputs on the fate of organochlorine pesticides in sediments of the Yellow and East China seas

摘要

The distribution and fate of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in sediments from the East China Sea (ECS) and the Yellow Sea (YS) were compared and studied in this work. The ECS has directly large river-dominated inputs of sediment-associated pollutants while the YS does not. The results indicated that these mud deposits of the YS and ECS were the sinks of land-originated DDTs and HCHs. The consistence of these OCP species and total organic carbon (TOC) and the sediment grain size in the YS indicated that the shelf mud depositional process was the dominant factor in controlling the distribution and fate of these organic compounds under the more homogeneous and hydrodynamic-based sedimentary conditions of the YS. The distribution of these chemicals in the coastal ECS, however, showed a much different pattern where the concentrations of DDTs and HCHs decreased with distance from the coast, and the correlations between DDTs and HCHs with TOC were very poor. This indicates that the continuous transferring of organochlorine pesticides (OCPs) into the coastal ECS by the direct riverine inputs and surface runoffs play a key role on the occurrence and fate of OCPs within this more heterogeneous environmental system.