Closed lakes located in urban parks act as sinks of organochlorine pesticides (OCPs), which have been used, for decades, as insecticides, herbicides and fungicides. The closed lakes from Bucharest, Romania, are periodically managed to prevent eutrophication and accumulation of pollutants. However, it is not known if these practices reduce or enhance the legacy pollution with OCPs. The aim of this study was to explore the spatial variation of OCPs in closed lakes. The total concentration of OCPs in water and sediments ranged between 0.0176 and 37.1 µg/L, and between 122 to 1,890 ng/g, respectively. The concentrations of OCPs were compared with the consensus-based sediment quality guidelines (SQGs) in order to evaluate the ecological risks of sediments. The highest potential adverse effects were associated with γ-HCH exposure. Periodical draining and dredging of lakes lead to the resuspension of contaminants, increasing pesticide bioavailability and accumulation in sediments. In addition, we observed that fluorescent dissolved organic matter (DOM) might influence the OCPs cycle. The quantity and character of fluorescent DOM can provide further insight into OCPs degradation. Also, this study may help urban planners to determine the state of urban waters and to find the best solution for water management.

中文翻译：

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城市封闭湖泊中有机氯农药和溶解性有机物的空间变化

位于城市公园中的封闭湖泊起着有机氯农药（OCPs）的汇聚作用，数十年来一直用作杀虫剂，除草剂和杀真菌剂。罗马尼亚布加勒斯特的封闭湖泊得到定期管理，以防止富营养化和污染物累积。但是，尚不知道这些做法是否会减少或增强OCP的传统污染。这项研究的目的是探索封闭湖泊中OCP的空间变化。水和沉积物中OCP的总浓度分别在0.0176和37.1 µg / g之间，在122和1,890 ng / g之间。将OCPs的浓度与基于共识的沉积物质量准则（SQGs）进行了比较，以评估沉积物的生态风险。潜在的最高不良反应与γ-六氯环己烷接触有关。湖泊的定期排水和疏lead导致污染物的重新悬浮，增加了农药的生物利用度并增加了沉积物的积累。此外，我们观察到荧光溶解的有机物（DOM）可能会影响OCP循环。荧光DOM的数量和特性可以进一步了解OCP的降解。此外，这项研究还可以帮助城市规划者确定城市水域状况，并找到最佳的水管理解决方案。