太湖贡湖湾水体中微囊藻毒素的时空分布及健康风险评估

Spatial and Temporal Distribution and Health Risk Assessment of Microcystins in Water of Gonghu Bay, Taihu Lake

水环境中微囊藻毒素(MCs)的污染会对人体健康造成负面影响。现阶段MCs健康风险评估多是基于慢性暴露情景,在急性事件的评估中存在局限性。为了评估太湖贡湖湾水域MCs污染及其健康风险状况,采用酶联免疫法(ELISA)对贡湖湾11个监测点表层水中的MCs赋存状况进行1年的逐月监测,分析MCs的时空分布特征,并研究MCs的赋存与不同环境因子的关系。另外,结合MCs的急性毒性阈值,采用非致癌风险指数(HI)评价模型对其风险状况进行评价。在监测时段内,贡湖湾水体中的MCs浓度整体处于较低水平,总微囊藻毒素(TMC)的全年平均浓度为0.06μg·L-1,其中靠近西北岸的水体中MCs浓度相对较高;11月贡湖湾水体中MCs的赋存水平最高,TMC和胞外微囊藻毒素(EMC)的平均浓度分别达到0.10和0.07μg·L-1。贡湖湾水体中MCs浓度与氮磷比(N/P)之间具有显著的负相关性,表明N、P的含量变化会影响贡湖湾水体中MCs的赋存,而温度对贡湖湾水体中MCs浓度的影响并不显著。贡湖湾水体中MCs的HI风险指数范围为0.024～0.070,表明贡湖湾水体的MCs污染总体上处于极低或低风险水平,其中在11月风险指数相对较高;另外,靠近西北岸的S3、S4、S5点显现出了相对较高的风险等级。总体而言,贡湖湾水体中MCs的污染水平较低,引起人体健康风险的可能较小,然而,MCs的长期暴露是否会引起慢性健康风险尚未可知,仍需对MCs的污染加强监管。

Cyanobacterial bloom caused by water eutrophication would trigger various environmental problems.Due to the adverse effects on human health,pollution of microcystins(MCs)in aquatic environments has received long-term attentions from both public and scientific communities.Currently,most of the health risks assessments of MCs are based on the scenario of chronic exposure,while information on the acute risks of MCs is limited.To assess the pollution status of MCs and its health risks in Gonghu Bay of Taihu Lake,the surface waters were monthly collected from eleven sampling points for one year,and the MCs concentrations were detected by using enzyme-linked immunosorbent assay(ELISA).In this study,the spatial and temporal distribution of MCs in Gonghu Bay was firstly analyzed.Then,the relationship between MCs occurrence and different environmental factors was studied.Finally,based on the acute toxicity thresholds of MCs,the human health risks of MCs were evaluated by hazard index(HI)model.Throughout the monitoring duration,the concentration of MCs in the water of Gonghu Bay was low,with the average total MCs(TMC)concentration of 0.06μg·L-1.The MCs concentration near the northwest coast was higher than that near the southeast coast.Moreover,the pollution level of MCs in November was the highest,with the TMC and extracellular MCs(EMC)concentrations of 0.10μg·L-1 and 0.07μg·L-1,respectively.While the temperature did not exhibit any obvious effect on MCs concentration,there was a significantly negative relationship between MCs concentration and N/P,suggesting that the levels of N and P would affect the occurrence of MCs in Gonghu Bay.The HI degree of MCs ranged from 0.024 to 0.070 in Gonghu Bay with the highest HI degree in November,indicating a very low or low risk level of MCs pollution.The HI degrees in S3,S4 and S5,which located near the northwest coast of Gonghu Bay,were higher than those in the other sampling points.Overall,the MCs pollution in Gonghu Bay is at a relatively low level,and it is less likely to induce human health risks.However,information on chronic health risk caused by longterm exposure to MCs remains limited.Enhancement of monitoring and management for MCs pollution is still needed.