State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2021 Jul 20;55(14):9740-9749. doi: 10.1021/acs.est.1c01045. Epub 2021 Jul 2.
Although organochlorine pesticides (OCPs) have been banned for more than three decades, their concentrations have only decreased gradually. This may be largely attributable to their environmental persistence, illegal application, and exemption usage. This study assessed the historic and current regional context for dichlorodiphenyltrichloroethane (DDT), chlordane, and hexachlorobenzene (HCB), which were added to the Stockholm Convention in 2001. An air sampling campaign was carried out in 2018 in nine cities of the Pearl River Delta (PRD), where the historical OCP application was the most intensive in China. Different seasonalities were observed: DDT exhibited higher concentrations in summer than in winter; chlordane showed less seasonal variation, whereas HCB was higher in winter. The unique coupling of summer monsoon with DDT-infused paint usage, winter monsoon with HCB-combustion emission, and local chlordane emission jointly presents a dynamic picture of these OCPs in the PRD air. We used the BETR Global model to back-calculate annual local emissions, which accounted for insignificant contributions to the nationally documented production (<1‰). Local emissions were the main sources of -DDT and chlordane, while ocean sources were limited (<4%). This study shows that geographic-anthropogenic factors, including source, history, and air circulation pattern, combine to affect the regional fate of OCP compounds.
尽管有机氯农药（OCPs）已经被禁用了三十多年，但它们的浓度仍在逐渐下降。这主要可能归因于它们在环境中的持久性、非法应用和豁免使用。本研究评估了 2001 年加入《斯德哥尔摩公约》的滴滴涕、氯丹和六氯苯的历史和当前区域背景。2018 年在珠江三角洲（PRD）的九个城市进行了一次空气采样活动，该地区是中国 OCP 应用最集中的地区。观察到不同的季节性：滴滴涕在夏季的浓度高于冬季；氯丹的季节性变化较小，而六氯苯在冬季的浓度较高。夏季季风与滴滴涕涂料使用、冬季季风与六氯苯燃烧排放以及当地氯丹排放的独特耦合，共同呈现了 PRD 空气中这些 OCP 的动态图。我们使用 BETR Global 模型反算得出的年度本地排放，对全国记录的生产（<1‰）贡献不大。本地排放是 -DDT 和氯丹的主要来源，而海洋来源有限（<4%）。本研究表明，地理-人为因素，包括来源、历史和空气环流模式，共同影响 OCP 化合物的区域命运。
