State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Sci Pollut Res Int. 2020 Dec;27(36):45095-45107. doi: 10.1007/s11356-020-10384-0. Epub 2020 Aug 10.
The frequent occurrence of microcystins (MCs) in freshwater poses serious threats to the drinking water safety and health of human beings. Although MCs have been detected in individual fresh waters in China, little is known about their occurrence over a large geographic scale. An investigation of 30 subtropical lakes in eastern China was performed during summer 2018 to determine the MCs concentrations in water and their possible risk via direct water consumption to humans, and to assess the associated environmental factors. MCs were detected in 28 of 30 lakes, and the highest mean MCs concentrations occurred in Lake Chaohu (26.7 μg/L), followed by Lake Taihu (3.11 μg/L). MC-LR was the primary variant observed in our study, and MCs were mainly produced by Microcystis, Anabaena (Dolicospermum), and Oscillatoria in these lakes. Replete nitrogen and phosphorus concentrations, irradiance, and stable water column conditions were critical for dominance of MC-producing cyanobacteria and high MCs production in our study. Hazard quotients indicated that human health risk of MCs in most lakes was at moderate or low levels except Lakes Chaohu and Taihu. Nutrient control management is recommended to decrease the likelihood of high MCs production. Finally, we recommend the regional scale thresholds of total nitrogen and total phosphorus concentrations of 1.19 mg/L and 7.14 × 10 mg/L, respectively, based on the drinking water guideline of MC-LR (1 μg/L) recommended by World Health Organization. These targets for nutrient control will aid water quality managers to reduce human health risks created by exposure to MCs.
微囊藻毒素（MCs）在淡水中频繁出现，对人类饮用水安全和健康构成严重威胁。尽管在中国个别淡水水域已经检测到 MCs，但对于其在大地理范围内的发生情况却知之甚少。本研究于 2018 年夏季对中国东部 30 个亚热带湖泊进行了调查，以确定水中 MCs 的浓度及其通过直接饮用水对人类可能造成的风险，并评估相关的环境因素。在 30 个湖泊中有 28 个湖泊中检测到了 MCs，其中巢湖的 MCs 平均浓度最高（26.7μg/L），其次是太湖（3.11μg/L）。在本研究中观察到的主要变异体是 MC-LR，MCs 主要由这些湖泊中的微囊藻、鱼腥藻（Dolicospermum）和颤藻产生。氮磷充足、光照和稳定的水柱条件是这些湖泊中产生 MC 的蓝藻优势和高 MCs 产生的关键因素。危害商数表明，除了巢湖和太湖外，大多数湖泊的 MCs 对人类健康的风险处于中等或低水平。建议进行营养物控制管理，以降低高 MCs 产生的可能性。最后，我们建议基于世界卫生组织（WHO）推荐的 MC-LR（1μg/L）饮用水指南，将总氮和总磷的区域尺度阈值分别设定为 1.19mg/L 和 7.14×10mg/L。这些营养物控制目标将有助于水质管理人员降低人类暴露于 MCs 所造成的健康风险。
