晋江河口柱状沉积物中重金属的赋存形态及生态风险评价

采用改进的BCR连续提取法对晋江河口柱状沉积物中的重金属(Fe、Zn、Ni、Pb、Cu和Cr)进行形态分析。结果表明,在垂向分布上重金属的形态分布基本一致。其中,Fe主要存在于残渣态,Pb、Cu和Ni主要存在于可还原态,Zn主要存在于弱酸溶态,Cr主要存在于可氧化态。各金属总可提取态占总量的比值(即生物有效性)排序为:CuCrPb=Zn=NiFe,Cu、Cr、Pb、Zn和Ni的迁移性和生物有效性均较高,对环境存在较大的潜在危害。运用次生相与原生相比值法对重金属潜在生态风险进行评价,结果表明:Fe处于无污染水平,Zn、Pb、Ni、Cu和Cr均处于中到重度污染水平。

Speciation and Ecological Risk of Heavy Metals in the Core Sediment from the Jinjiang Estuary

Speciation of heavy metals (Fe, Zn, Ni, Pb, Cu and Cr) in the core sediment from the Jinjiang estuary was analyzed using the modified BCR sequential extraction procedure. The results showed that the speciation of heavy metals is coincident basically in the vertical distribution. Iron is mainly in the residual fraction, Pb, Cu and Ni are mainly in the reducible fraction, Zn is mainly in the acid soluble fraction and Cr is mainly in the oxidizable fraction. By considering the percentage of the extractable fractions (sum of the first three steps) of heavy metals, the mobility order is Cu > Cr > Pb=Zn=Ni > Fe. Zinc, Ni, Pb, Cu and Cr exhibit higher mobility, bioavailability and potential risk to the environment. The ratios of secondary phase to primary phase of heavy metals showed that Fe presents no pollution, while Zn, Pb, Ni, Cu and Cr are at the moderate pollution level to the severe pollution level.