Distribution and flux of organochlorine pesticides in sediment from Prydz Bay, Antarctic: Implication of sources and trends

Surface sediments were collected from Prydz Bay, Antarctica to investigate the distribution patterns, origins, annual fluxes, and trends of organochlorine pesticides (OCPs) in the marginal sea of polar areas. The concentrations of OCPs ranged from 0.80 to 7.90 ng/g dry weight, with dichlorodiphenytrichloroethanes (DDTs) as the main components. Levels of hexachlorocydohexanes (HCHs) and DDTs in sediment from Prydz Bay were comparable to the majority of marine sediment worldwide. The distributions of OCPs were characterized by a distinct quasiconcentric circle pattern, which has significantly positive relationship with total organic carbon (TOC) of sediment and controlled by the local hydrodynamic conditions and sources of organic matter. Source apportionment demonstrated that HCHs and chlordanes in Prydz Bay were mainly derived from the long range atmospheric transport (LRAT) of these compounds from off regions. However, current inputs of DDT-based compounds and lindane are suggested to exist either as a result of the LART from the neighbouring countries or re-emission from melting glacier. The annual sedimentary fluxes of OCPs were 0.007 to 7.12 pg/cm(2)/yr, about one to three orders of magnitude lower than some data from the Arctic areas. Based on a rough calculation of r-HCH, only 0.3-1.5% of the air-seawater net deposition would be buried in sediment, implying a long active lifetime of OCPs in Antarctica. We preliminarily indicate an increase of OCP contamination in Antarctic environment afterwards when considering the possible occurrence of fresh sources and low proportion of sedimentary sink. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study on the distribution patterns of OCPs in the surface sediments collected from Prydz Bay, Antarctica revealed that concentrations were mainly influenced by HCHs and DDTs, with a distinct quasiconcentric circle pattern controlled by total organic carbon and local hydrodynamic conditions. Source apportionment indicated that HCHs and chlordanes were primarily derived from long range atmospheric transport. Annual sedimentary fluxes of OCPs in Antarctica were one to three orders of magnitude lower than some data from the Arctic areas, implying a long active lifetime of OCPs in the Antarctic environment.