孝妇河水体沉积物中重金属的污染及形态分布特征

CHARACTERISTIC OF CONTAMINATION AND SPECIATION OF HEAVY METALS IN SEDIMENT OF XIAOFU RIVER IN THE ZIBO SECTION

为了解孝妇河流域淄博段的水体沉积物的重金属污染特征,采集了9个表层沉积物样品,测定了沉积物的理化性质、重金属Cu、Cr、Pb和Ni的总量及其化学形态,并采用潜在生态风险指数法对重金属的污染程度及存其在的生态风险进行了分析.结果显示,孝妇河沉积物中Cu、Cr、Pb和Ni的总体含量分别为18.6—42.3mg.kg-1,13.6—31.6mg.kg-1,11.1—30.4mg.kg-1,17.6—29.4mg.kg-1;且均主要以结晶态存在,其次为可氧化态,可还原态及酸溶态所占的比例较低;其中,Cu的酸溶态所占比例为0—12.8%,迁移性最强,发生复溶的可能性最大.潜在生态生风险指数法分析表明,孝妇河表层沉积物受Cu、Ni污染程度达到中度,存在生态风险相对较大,应予以重视.

To understand the characteristic of contamination and speciation of heavy metals in the surface sediment of Xiaofu river,nine samples of surface sediment were collected.Organic matter content,pH,and Eh of these sediment samples were measured.Total contents and chemical speciation of Cu,Cr,Pb and Ni in the sediment were determined.The total contents of Cu,Cr,Pb and Ni in the sediment were 18.6—42.3mg·kg^-1,13.6—31.6mg·kg^-1,11.1—30.4mg·kg^-1,17.6—29.4mg·kg^-1,respectively.The results show that Cu,Cr,Pb and Ni mainly existed in sediment as oxidable fraction and crystallization;The ratio of weak acid extraction to heavy metal concentration in sediment was 0—12.8%（Cu）,0—8.0%（Cr）,0—4.0%（Pb）,0—2.7%（Ni）,respectively.That is,Cu in sediment was easier to transport to water environment than other three heavy metals.The result of the Potential Ecological Risk Index analysis indicated that the sediment of Xiaofu river was minor/slightly polluted by Cu and Ni,and the their ecological risk was relatively high.More attention shuld be given to the contamination of Cu and Ni than that of Cr and Ni in sediment of Xiaofu river.