Zhang Shengwei, Zhao Wenyu, Yang Chao, Li Yanxia, Liu Mengyue, Meng Xiang Zhou, Cai MingHong
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China; Ministry of Natural Resources Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, 200136, China.
School of Chemistry and Food Engineering, Changsha University of Science & Technology, Changsha, 410114, China.
Environ Pollut. 2022 Jul 1;304:119133. doi: 10.1016/j.envpol.2022.119133. Epub 2022 Mar 22.
Xiangjiang (XJ) is a typical urban inland river that serves as a drinking water source, which may be affected by the currently used organochlorine pesticides (CUOCPs) originating from agricultural activities in the vicinity. On this basis, this study comprehensively explored the occurrence and distribution characteristics of CUOCPs in surface water and sediments under long-term precipitation and subsequent floods. Considering the low concentration of CUOCPs in water, a technique combining high-throughput organic analysis with high-volume solid phase extraction (High-throat/Hi-volume SPE) was introduced for effective analysis of CUCOPs. The results showed that the concentration of CUOCPs in the water and sediments of XJ ranged from 2.33 to 6.40 ng L (average of 3.93 ± 1.15 ng L) and from 1.52 to 21.2 ng g (average of 6.60 ± 4.31 ng g dw), respectively. The distribution of CUOCPs in water was consistent throughout XJ, but that in sediments was not uniform, indicating a stronger impact of floods on water than on sediments. Water-sediment partition coefficients were generally >2 L g, showing a tendency of CUOCP dominance in sediments. The results of principal component analysis and cluster analysis showed that the occurrence of CUOCPs is significantly affected by exogenous disturbance, which could be flood events; meanwhile, clusters of CUOCPs were found in both water and sediments in the source-limited middle reaches in urban areas. Redundancy analysis (RDA) showed that CUOCP occurrences were not positively correlated with nutrient elements (nitrogen and phosphorus), but related to pH and dissolved oxygen (DO), indicating complex sources.
湘江（XJ）是一条典型的城市内河，用作饮用水源，可能受到附近农业活动中目前使用的有机氯农药（CUOCPs）的影响。在此基础上，本研究全面探讨了长期降雨及后续洪水作用下，地表水和沉积物中CUOCPs的发生及分布特征。考虑到水中CUOCPs浓度较低，引入了高通量有机分析与大体积固相萃取相结合的技术（High-throat/Hi-volume SPE）以有效分析CUCOPs。结果表明，湘江水体和沉积物中CUOCPs的浓度分别为2.33至6.40 ng/L（平均3.93±1.15 ng/L）和1.52至21.2 ng/g（平均6.60±4.31 ng/g干重）。CUOCPs在湘江水体中的分布是一致的，但在沉积物中分布不均，表明洪水对水体的影响比对沉积物的影响更大。水-沉积物分配系数一般>2 L/g，表明CUOCPs在沉积物中占主导趋势。主成分分析和聚类分析结果表明，CUOCPs的出现受外源干扰显著影响，这种干扰可能是洪水事件；同时，在城市水源受限的中游河段，水体和沉积物中均发现了CUOCPs聚类。冗余分析（RDA）表明，CUOCPs的出现与营养元素（氮和磷）无正相关，但与pH值和溶解氧（DO）有关，表明其来源复杂。
