太湖典型水源地挥发性有机物与环境因子的关系

Relationship between Volatile Organic Compounds and Environmental Factors in Typical Water Sources of Taihu Lake

在太湖渔洋山水源地建立水质自动监测系统,于2018年4月—2019年3月进行为期1年的挥发性有机物(VOCs)与环境因子(温度、pH、电导率、浊度、溶解氧、氨氮、总氮、总磷、高锰酸盐指数、总有机碳、叶绿素a、蓝绿藻)监测,监测频次为每4 h 1次。筛选检出率较高的3种VOCs(二氯甲烷、苯乙烯、萘),并分析这3种VOCs与环境因子的相关关系。结果表明,2018年4月—2019年3月研究水域内苯乙烯、萘浓度呈现逐月降低的趋势,变化趋势基本一致,二氯甲烷浓度呈现先上升后下降的趋势。二氯甲烷与环境因子没有表现出较强的相关性,苯乙烯与pH表现出较强的正相关性,萘与水温、电导率表现出较强的正相关性,萘与溶解氧、高锰酸盐指数表现出较强的负相关性,苯乙烯与萘表现出较强的正相关性。水体降温和底泥固定(沉水植物生态修复)将是有效降低湖泊水体VOCs浓度的方法。

An automatic water quality monitoring system was established in the YuYang-Mountain water source area of Taihu Lake to monitor volatile organic compounds(VOCs)and environmental factors(temperature,pH,conductivity,turbidity,dissolved oxygen,ammonia nitrogen,total nitrogen,total phosphorus,permanganate index,total organic carbon,chlorophyll a,blue-green algae)for a period of one year from April 2018 to March 2019,and the monitoring frequency was 1 time every 4 hours.Three kinds of VOCs with high detection rate were screened:dichloromethane,styrene and naphthalene,and the correlation between these three kinds of VOCs and environmental factors was analyzed.The results showed that from April 2018 to March 2019,the concentration of styrene and naphthalene in the study waters showed a monthly decreasing trend,and the variation trend was basically the same,while the concentration of dichloromethane showed a trend of first increasing and then decreasing.There was no strong correlation between dichloromethane and environmental factors;styrene and pH showed a strong positive correlation;naphthalene showed a strong positive correlation with water temperature and electrical conductivity;naphthalene showed a strong negative correlation with dissolved oxygen and permanpermanate index;styrene and naphthalene showed a strong positive correlation.Water cooling and sediment fixation(submerged plant ecological restoration)are the effective methods to reduce VOCs concentration in lake water.