摘要
测定了娄山河表层沉积物间隙水中重金属(Cu、As、Pb、Zn、Cr、Cd和Ni)的质量浓度,采用改正的BCR顺序提取法分析了沉积物中重金属的赋存形态,并分别基于美国水质基准(CCC、CMC)和风险评价编码法(RAC)、潜在生态风险指数法对间隙水和表层沉积物中重金属的毒性及生态风险进行评价.结果表明,娄山河表层沉积物间隙水中Cr、Pb可能对水生态系统产生急性或慢性毒性.沉积物中7种重金属的含量均高于土壤背景值,呈现累积效应.沉积物中As、Ni主要赋存于残渣态,Cu、Cr主要赋存于可氧化态和残渣态,Pb、Zn在多数点位以残渣态为主,Cd以酸可溶解态为主要赋存形态.除As外,其余重金属的可提取态含量高于残渣态,有较高的二次释放潜力.RAC的评价结果表明,表层沉积物中Cu、As、Pb和Cr处于无风险到低风险级,Zn、Ni处于低风险到高风险级,Cd以高风险和极高风险级为主,不同重金属RAC的平均值依次为Cd>Zn>Ni>Pb>Cu>As>Cr.潜在生态风险指数法的评价结果表明,Zn为低生态风险,其余重金属均存在点位处于中等及以上生态风险,RI值表明研究区采样点有中等到极强生态风险.
The concentrations of Cu, As, Pb, Zn, Cr, Cd and Ni were analyzed in interstitial water from Loushan River by ICP-MS. A modified BCR＇s sequential extraction procedure was used to investigate the fraction of the heavy metals in surface sediments. The aquatic toxicity of heavy metals in interstitial water was assessed by US Water Quality Criteria（CCC, CMC）. Based on speciation of the heavy metals in the sediments, their ecological risk was assessed with the methods of risk assessment code（RAC） and potential ecological risk index. The results show that Cr and Pb pose acute or chronic toxicity for aquatic ecosystem in some sampling locations. Contents of the heavy metals in the sediments were higher than the background values of the local soils, indicating enrichment of the heavy metals. As and Ni were primarily in residual fractions, while Cu and Cr were mainly present in residual and oxidisable fractions. Although Pb and Zn exist mainly in residual fractions in the majority of the sampling locations, Cd exist mainly in acid soluble faction. The bio-available fractions of Cu, Pb, Zn, Cr, Cd and Ni were higher than the residual fractions in the sediments, indicating a high potential for secondary release. Based on the calculations with the RAC method, Cu, As, Pb and Cr pose an extremely low to low risk to the environment. Accordingly, Zn and Ni pose low to high risk, and Cd is mainly of high to extreme high risk to the environment. The potential ecological risk of the heavy metals in the sediments is in the order of Cd〉Zn〉Ni〉Pb〉Cu〉As〉Cr. Zn has low ecological risk, and the other heavy metals have medium to extremely high potential ecological risk at some sampling locations. The potential ecological risk Indices（RI） indicate the heavy metals in the sediments pose medium to extremely high potential ecological risks to the Loushan River.
出处
《环境化学》
CAS
CSCD
北大核心
2016年第2期393-402,共10页
Environmental Chemistry
基金
底泥重金属处理处置技术研究与工程示范(SDHBYF-2012-14)资助~~
关键词
娄山河
间隙水
表层沉积物
重金属
赋存形态
风险评价
Loushan River, interstitial water, surface sediments, heavy metals, speciation, risk assessment.
