School of Environmental Science & Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, E1A 07-03, Singapore 117576, Singapore; NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, #02-01, Singapore 117411, Singapore.
Ecotoxicol Environ Saf. 2018 Dec 30;166:320-327. doi: 10.1016/j.ecoenv.2018.09.107. Epub 2018 Sep 29.
The water environment from river to reservoir has been considered as a hybrid river-reservoir system due to pronounced environmental properties. This study investigated the distribution and potential environmental behavior of pesticides in river-reservoir system, examining 31 target pesticides in water phase from a key drinking water source (Dongjiang River). The concentrations of ∑OCPs, ∑OPPs and ∑SPs with the corresponding occurrence were in the range of 107.57-340.35 ng/L (moderate level), 232.65-1197.95 ng/L (moderate level) and 125.23-245.09 ng/L (low level), respectively. Ecological risk assessments indicated that most of the pesticides posed a high level of risk to the aquatic organisms. Moreover, seasonal agricultural application, rainfall and temperature could influence the levels and compositions of ∑OCPs, ∑OPPs and ∑SPs in the river system, while seasonal hydrological processes could only influence their compositions in the reservoir system. In the wet season, the levels of ∑OCPs and ∑SPs decreased from the river system to reservoir system probably via biogeochemical processes, while the level of ∑OPPs decreased along the environmental gradient probably via dilution process. Additionally, longer hydraulic retention time of the reservoir system could contribute to the biogeochemical processes for OPPs and SPs exported from the river system, but it might fail to facilitate this process for OCPs. Taken together, this study highlighted that the distributions and environmental behavior of pesticides in river-reservoir system varied seasonally from river system to reservoir system.
由于显著的环境特性，从河流到水库的水环境被认为是一种混合河流-水库系统。本研究调查了河流-水库系统中农药的分布和潜在环境行为，检测了来自主要饮用水源（东江）水相中 31 种目标农药。∑OCPs、∑OPPs 和∑SPs 的浓度及其相应的出现率分别在 107.57-340.35ng/L（中等水平）、232.65-1197.95ng/L（中等水平）和 125.23-245.09ng/L（低水平）之间。生态风险评估表明，大多数农药对水生生物构成高度风险。此外，季节性农业应用、降雨和温度会影响水系中∑OCPs、∑OPPs 和∑SPs 的水平和组成，而季节性水文过程只能影响水库系统中它们的组成。在雨季，∑OCPs 和∑SPs 的水平从河流系统到水库系统降低，可能是通过生物地球化学过程，而∑OPPs 的水平沿环境梯度降低，可能是通过稀释过程。此外，水库系统较长的水力停留时间可能有助于从河流系统输出的 OPPs 和 SP 的生物地球化学过程，但可能不利于 OCPs 的这种过程。综上所述，本研究强调了河流-水库系统中农药的分布和环境行为从河流系统到水库系统随季节变化而变化。
