Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
Sci Total Environ. 2023 Aug 1;884:163701. doi: 10.1016/j.scitotenv.2023.163701. Epub 2023 Apr 25.
Suspended particulate matter (SPM) plays an important role in the geochemical behavior and fate of organic micropollutants in aquatic environments. However, the presence of trace emerging endocrine disruptors such as environmental corticosteroids (ECs) in SPM is less well understood. This study focused on the occurrence, distribution, and partitioning of SPM-associated ECs in the Pearl River system, China. Ubiquitous particulate ECs were found in the surface water of the rivers at average concentrations (dry weight) between 0.46 ng/g (flumethasone) and 8.83 ng/g (clobetasone butyrate). The total EC (∑ECs) concentrations of the 24 selected target compounds varied from <1.03 ng/g to 62.3 ng/g, with an average and median of 17.6 ng/g and 13.7 ng/g, respectively. Higher SPM-bound EC levels were commonly observed in winter (dry season), and spatially, their relatively high contamination in urban tributary networks decreased while flowing to mainstreams and then gradually attenuated from upstream to the estuary. Despite the approximately 90 % mass distribution of ∑ECs in the aqueous phase, approximately 50 % of their effect burden was derived from the suspended particulate fractions. For the first time, in situ SPM-water partitioning coefficients (K) and their organic carbon-normalized ones (K) of ECs were determined in surface waters, and a field-derived preliminary linear equation was proposed to estimate K for ECs using basic physicochemical parameters n-octanol/water partitioning coefficient (K), which is of importance with regard to the assessment of transport, fate, and risk of these emerging hazardous chemicals. Furthermore, the significant logK-logK relationship for ECs reveals that nonspecific hydrophobic partitioning is a major association mechanism between SPM and ECs. Moreover, hydrogen bonding is suggested to be a prevailing specific binding mechanism and provides more contribution to nonhydrophobic interactions between ECs and particulate organic matter than environmental estrogens.
悬浮颗粒物 (SPM) 在水生环境中有机微量污染物的地球化学行为和归宿中起着重要作用。然而，痕量新兴内分泌干扰物如环境皮质甾类（ECs）在 SPM 中的存在情况了解较少。本研究重点关注中国珠江系统中 SPM 相关 ECs 的发生、分布和分配。在河流的地表水发现普遍存在颗粒态 ECs，其平均浓度（干重）在 0.46ng/g（氟替卡松）和 8.83ng/g（氯倍他索丁酸酯）之间。24 种选定目标化合物的总 EC（∑ECs）浓度范围从<1.03ng/g 到 62.3ng/g，平均值和中位数分别为 17.6ng/g 和 13.7ng/g。冬季（旱季）通常观察到更高的 SPM 结合态 EC 水平，空间上，随着从支流流向干流以及从上游到河口逐渐减弱，其在城市支流网络中的相对高污染程度有所降低。尽管∑ECs 约有 90%的质量分布在水相中，但它们约有 50%的效应负荷来自悬浮颗粒物部分。首次在地表水中测定了 ECs 的原位 SPM-水分配系数 (K)及其有机碳归一化值 (K)，并提出了一个基于基本物理化学参数正辛醇/水分配系数 (K)的现场推导初步线性方程，用于估算 ECs 的 K，这对于评估这些新兴危险化学品的迁移、归宿和风险具有重要意义。此外，ECs 的显著 logK-logK 关系表明，非特异性疏水性分配是 SPM 与 ECs 之间主要的结合机制。此外，氢键被认为是一种主要的特异性结合机制，对 ECs 与颗粒有机物质之间的非疏水相互作用的贡献大于环境雌激素。
