淀山湖微囊藻毒素含量与环境污染因子变化相关性分析

Correlation analysis of microcystin contents and change of environmental pollution factors in Dianshan Lake

目的了解淀山湖环境水体中微囊藻毒素(MC-LR)污染现况及与环境污染因子的相关性。方法于2016年3—9月间在上海淀山湖青浦界内依据地理位置和功能不同设立5个水质监测点,每月进行水样采集,涵盖淀山湖枯水期、平水期和丰水期。依据GB 3838-2002《地表水环境质量标准》中地表水Ⅲ类标准对结果进行评估,对MC-LR与环境污染物进行相关性分析。结果淀山湖污染物MC-LR为(13.98±16.99)ng/L,与总磷、总氮有相关性,结果差异有统计学意义。总磷为(0.16±0.04)mg/L,总氮为(3.02±1.23)mg/L,氨氮为(0.82±0.52)mg/L,均超过国家地表水Ⅲ类标准;高锰酸盐指数为(4.98±0.65)mg/L、叶绿素为(5.66±3.29)mg/L和MC-LR达到国家地表水Ⅲ类标准。结论淀山湖水体中微囊藻毒素(MC-LR)与环境水体中总磷总氮相关性显著,与其他营养物质相关性不明显。淀山湖水体总体质量有所改善,但总磷总氮超标,水质呈中度营养化,早期监测总磷和总氮对评价MC-LR污染有预警意义。

[Objective] To understand the pollution situation of microcystin（MC-LR） and its correlation with environmental pollution factors in Dianshan Lake. [Methods] Based on geographical positions and different functions, five water quality monitoring points were established in Dianshan Lake of Qingpu district, and water samples were collected once a month during March to September of 2016, including low-flow period, mean-flow period and high-flow period of Dianshan Lake. The results were evaluated according to category Ⅲ of GB3838-2002 ＂Natioanl Surface Water Quality Standards＂, and the correlation between MC-LR and environmental pollutants was analyzed. [Results] The level of MC-LR was（13.98 ±16.99） ng/L, which correlated with the levels of total nitrogen and total phosphorus, and the difference was statistically significant. The level of total phosphorus was（0.16 ±0.04） mg/L, total nitrogen was（3.02 ±1.23） mg/L, ammonia nitrogen was（0.82 ±0.52） mg/L, which exceeded the national standard for surface water category Ⅲ. The permanganate index was（4.98 ±0.65） mg/L, chlorophyll was（5.66±3.29） mg/L, which with MC-LR reached the national standard for surface water category Ⅲ. [Conclusion] The correlation of MC-LR in Dianshan Lake with total nitrogen and total phosphorus is significance, but has no significant correlation with other nutrient substance. The overall water quality of Dianshan Lake is improved, but the total nitrogen and total phosphorus exceed the standard. The water quality shows severe eutrophication. Early monitoring of total phosphorus and total nitrogen may establish early-warning of MC-LR pollution.