Institute for Geography and Geology, University of Greifswald, F.L.-Jahn Str. 16, 17489, Greifswald, Germany.
School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa.
Environ Sci Pollut Res Int. 2023 Jan;30(1):2247-2259. doi: 10.1007/s11356-022-22298-0. Epub 2022 Aug 5.
The occurrence and distribution of organochlorine pesticides (OCPs) in aquatic systems is a matter of global concern and poses significant toxicological threats to both organisms and human health. Despite the extensive use of OCPs for pest and disease control in southern Africa, relatively few studies have examined the occurrence and toxicological risks of OCP residues in the region. This study investigates the composition, distribution, and potential sources of OCP contamination in sediments from Richards Bay, a rapidly developing industrial port on the northeast coast of South Africa. Surface sediments collected from Richards Bay Harbour and surrounding areas indicate that OCP contamination in the region is widespread. Total concentrations (∑OCP) in surface samples ranged from 135 to 1020 ng g, with hexachlorocyclohexanes (∑HCH; 35-230 ng g) and dichlorodiphenyltrichloroethanes (∑DDT; 12-350 ng g) the dominant contaminant groups detected. Metabolite isomeric compositions indicate that the presence of aldrin and endosulfan likely result from historical agricultural usage, while recent input of γ-HCH, heptachlor, and endrin may be linked to the illegal use of old pesticide stockpiles. Total DDT concentrations were dominated by p,p'-DDT (80 ± 64 ng g), which was attributed to its ongoing use in malaria vector control in the region. A Pb-dated sediment core revealed that OCP input to the local environment increased dramatically from relatively low concentrations in the mid-1940s (∑OCP, 355 ng g) to peak levels (∑OCP, 781 ng g) in the 1980s/1990s. An overall decrease in ∑OCP concentration from the mid-2000s is likely related to restrictions on use following the Stockholm Convention in 2004. Despite current restrictions on use, OCP concentrations exceeded sediment quality guidelines in the vast majority of cases, raising concerns for protected estuarine and mangrove habitats in the area, as well as for local fishing and farming communities.
有机氯农药 (OCPs) 在水生系统中的出现和分布是一个全球性关注的问题，对生物和人类健康构成了重大的毒理学威胁。尽管 OCPs 在南部非洲被广泛用于病虫害防治，但该地区对 OCP 残留的发生和毒理学风险进行研究的相对较少。本研究调查了南非东北海岸快速发展的工业港口理查兹湾沉积物中 OCP 污染的组成、分布和潜在来源。从理查兹湾港和周边地区采集的表层沉积物表明，该地区的 OCP 污染广泛存在。表层样品中总浓度（∑OCP）范围为 135 至 1020ng/g，其中六氯环己烷（∑HCH；35-230ng/g）和滴滴涕（∑DDT；12-350ng/g）是主要的污染物。代谢物异构体组成表明，存在的艾氏剂和硫丹可能是由于历史上农业用途造成的，而近期γ-六氯环己烷、七氯和异狄氏剂的输入可能与旧农药库存的非法使用有关。总滴滴涕浓度主要由 p,p'-滴滴涕（80±64ng/g）组成，这归因于该地区正在进行的疟疾病媒控制。一个铅年代测沉积物核心表明，当地环境中 OCP 的输入从 20 世纪 40 年代中期（∑OCP，355ng/g）相对较低的浓度急剧增加到 20 世纪 80 年代/90 年代的峰值（∑OCP，781ng/g）。从 21 世纪中期开始，∑OCP 浓度的总体下降可能与 2004 年《斯德哥尔摩公约》实施后对使用的限制有关。尽管目前对使用的限制，但在绝大多数情况下，OCP 浓度仍超过了沉积物质量指南，这引起了人们对该地区受保护的河口和红树林栖息地以及当地渔业和农业社区的关注。
