清江流域地表水重金属季节性分布特征及健康风险评价

Seasonal Distribution Characteristics and Health Risk Assessment of Heavy Metals in Surface Water of Qingjiang River

为明确清江流域地表水中重金属健康危害程度,本文以清江地表水为研究对象,选取清江主要一级支流入江口及主干流设置采样断面取样,对样品中Cr、Cu、Zn、Pb、Cd、As和Mn这7种重金属进行测定分析,使用USEPA的水环境健康风险评价模型对研究区丰枯两季地表水中重金属对成人与儿童产生的健康危害进行对比评估.结果表明,研究区主要超标重金属为Mn,集中于下游丹水、沿头溪和平洛溪附近,As略有超标,集中于下游伍家河附近,枯水期各重金属浓度均略大于丰水期,但差异性不大;Cr、Cu、Zn和Cd主要为自然来源,Pb主要来源于道路交通,As主要来源于农业活动,Mn在下游主要来源于采矿业,上游至中游主要为自然来源;地表水中各重金属对成人和儿童所产生的健康危害枯水期>丰水期,主要健康风险危害区域为中游支流和干流,主要产生健康危害元素为As,儿童为主要防控人群,饮用中游支流和干流附近地表水源的村镇居民需要引起格外重视.

In order to assess the health risks of heavy metals in surface water of Qingjiang River,surface water samples were taken at designed cross-sections of the river and analyzed for Cr,Cu,Zn,Pb,Cd,As,and Mn.Health risks from these heavy metals for adults and children in wet and dry seasons were compared by water environmental health risk assessment model of the USEPA.It found that the main excessive element is Mn,concentrating in the Danshui,Yantouxi,and Pingluoxi,the slightly excessive element is As,the concentration of Mn was above national standard,and it mainly distributed in Danshui,Yantouxi,and Pingluoxi,As was slightiy over the standard,and it concentrated in Wujiahe,The content of heavy metals during wet season were all higher than those during dry season.Cr,Cu,Zn,and Cd are mainly originated from the nature,Pb and As are separately mainly originated from traffic and agriculture,Mn originated from mining mainly in the downstream,while it has natural source from upper to middle.The health risks of heavy metals in surface water to adults and children in wet season are higher than those in dry season.The main health risk area was the midstream.As was the highest health risk element and children were the most preventive group.Specially,people in towns who drink the water from midstream should pay more attention.