大宝山污灌区水体与土壤重金属污染分析与评价

Analysis and Evaluation of Heavy Metal Pollution for Water and Soils in Dabaoshan Sewage Irrigation Area

通过在大宝山矿区采集橫石河不同河段水样和河流沿岸土壤样品,测定水体和土壤的ph值、Cu、Zn、pb和aS等重金属含量,运用单因子指数和综合污染指数评价法研究矿区水质和土壤重金属的分布特征与污染现状。结果表明:(1)接受尾矿污水的横石河中游区域水体明显酸化,ph值为3.28。水体Zn和pb浓度分别为3.91和1.30 mg/l,其超标倍数分别为1.96和6.48。此外,水体Cu、Zn、pb和aS等重金属含量沿河流流向呈现降低趋势。(2)橫石河沿岸土壤的ph值范围为4.63~5.73,土壤均呈酸性。橫石河右岸非污灌区利用未受污染的横石河上游水源灌溉,农田土壤未出现重金属含量超标。橫石河左岸污灌区长期利用受污河水灌溉,稻田土壤呈现轻度至中度的重金属污染,其中Cu、Zn和aS平均浓度分别为224、256和48.6 mg/kg,最大超标倍数分别为5.61、1.58和2.47。受污河水灌溉是农业土壤重金属污染的重要来源。

River water of Hengshi River and paddy soils were collected from Dabaoshan Mine,for determining pH,Cu,Zn,Pb and As.Heavy metal pollution of water and soils is evaluated using single factor index and integrated pollution index.The results indicate that(1) Obvious acidification is observed in the midstream of Hengshi River receiving tailings wastewater,where the pH value is 3.28.The concentrations of Zn and Pb are determined at 3.91 and 1.30 mg/L,with the exceeding rates of 1.96 and 6.48,respectively.Additionally,the concentrations of heavy metals in water decrease along Hengshi River.(2)The soils collected along the Hengshi River were acid,where the pH values range in 4.63~5.73.The area located in the right bank is irrigated with unpolluted water from the upstream of Hengshi River,where the paddy soils show no heavy metal pollution.For the sewage irrigation area located in the left bank,the paddy soils exhibit slight to moderate pollution by heavy metals,where the mean concentrations are determined at 224,256 and 48.6 mg/kg,with the maximal exceeding rates of 5.61,1.58 and 2.47,for Cu,Zn and As,respectively.Irrigation with the polluted river water accounts for the pollution of heavy metals in the agricultural soils.