State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
Environ Pollut. 2021 Aug 15;283:117072. doi: 10.1016/j.envpol.2021.117072. Epub 2021 Apr 7.
Pesticides are widely used to alleviate pest pressure in agricultural systems, and atrazine is a typical diffuse pollutant and serves a sensitivity index for environmental characteristics. Based on the physicochemical properties of parent substances, degradation products of pesticides may pose a greater threat to aquatic ecosystems than pesticides. Atrazine and three primary degradation products (deethylatrazine (DEA), deisopropylatrazine (DIA) and didealkylatrazine (DDA)) were investigated in a semienclosed bay of the western Pacific Ocean. Seasonal surface water and suspended particulate sediment (SPS) samples were collected from the estuary and bay in January, April, and August 2019. The level of pesticide contamination was lower in the bay than in the estuary, and the pesticide concentration in the dissolved phase was higher than that in the adsorbed phase. The average concentrations of atrazine and the three degradation products in the three seasons ranged from 2.42 to 328.46 ng/L in water and from 0.07 to 12.75 ng/L in SPS. The proportion of atrazine among the four detected pollutants decreased from 0.7 to 0.1 in surface water and from 0.3 to 0.1 in SPS over the seasons. As the main degradation products, the concentration proportions of DDA and DEA reached as high as 0.6 in August. The ratio of DEA to atrazine (DEA/ATR) increased from January to August, which indicated the progressive degradation process in the bay. Single-factor analysis of variance and principal component analysis indicated that atrazine degradation was sensitive to temperature, dissolved oxygen, and salinity. These three factors accounted for almost 70% of the seasonal variance in atrazine without a quantification assessment of photolysis or bacteria. The spatial distributions of DEA in the three seasons demonstrated that wind and currents also played important roles in pollutant redistribution. The seasonal temporal and spatial correlations between water and SPS demonstrated the degradation patterns of atrazine in marine conditions, supporting the need for future detailed toxicity studies.
农药被广泛用于减轻农业系统中的害虫压力，而莠去津是一种典型的扩散污染物，可作为环境特征的敏感指标。基于母体物质的物理化学性质，农药的降解产物可能比农药对水生生态系统构成更大的威胁。在西太平洋的一个半封闭海湾中，对莠去津和三种主要降解产物（去乙基莠去津（DEA）、去异丙基莠去津（DIA）和二去烷基莠去津（DDA））进行了研究。2019 年 1 月、4 月和 8 月，从河口和海湾采集了季节性地表水和悬浮颗粒沉积物（SPS）样品。与河口相比，海湾中的农药污染程度较低，溶解相中的农药浓度高于吸附相。三个季节中莠去津和三种降解产物的平均浓度在水中为 2.42 至 328.46ng/L，在 SPS 中为 0.07 至 12.75ng/L。在所检测的四种污染物中，莠去津的比例从地表水的 0.7 降至 0.1，从 SPS 的 0.3 降至 0.1。作为主要降解产物，DDA 和 DEA 的浓度比例在 8 月高达 0.6。DEA 与莠去津（DEA/ATR）的比值从 1 月到 8 月增加，表明海湾中存在逐步降解过程。单因素方差分析和主成分分析表明，莠去津的降解对温度、溶解氧和盐度敏感。这三个因素占莠去津季节性方差的近 70%，而没有对光解或细菌进行定量评估。三个季节中 DEA 的空间分布表明，风和流在污染物再分布中也发挥了重要作用。水和 SPS 的季节性时空相关性表明了海洋条件下莠去津的降解模式，支持未来进行详细毒性研究的必要性。
