莱州湾表层沉积物中重金属分布特征和环境影响

Distributions and Impacts of Heavy Metals in the Surface Sediments of the Laizhou Bay

测定了莱州湾表层沉积物中重金属质量分数,探讨了它们的分布特征、来源及污染程度,平均值分别为Cu13.3 mg/kg,Zn 59.4 mg/kg,Pb 20.2 mg/kg,Cd 0.081 mg/kg,Cr 57.1 mg/kg,Ni 19.4 mg/kg,As 13.1 mg/kg和Hg 0.053 mg/kg。空间分布上,Cu,Zn,Pb,Cd,Ni,Cr和Hg东西方向由岸向湾中心质量分数呈递减趋势,北部海域重金属质量分数普遍大于南部海域。富集因子结果表明,Cu,Zn,Cd,Cr和Ni无明显富集,主要来自岩石的自然风化;As和Pb中度富集,既有自然源的贡献,也受到了人为活动的影响;Hg主要受人类活动的影响。生态风险分析显示,全部站位的As及近半站位的Ni质量分数位于效应浓度低值(ERL)与效应浓度中值(ERM)之间,只是偶尔产生不利的生态效应;全部站位的Cu,Zn,Pb,Cd,Hg和Cr(除L10质量分数在ERL与ERM之间)均低于ERL,几乎不会产生不利的生态效应。黄河口外和西北缘近岸海域沉积物的综合环境质量较差,应引起重视。

The heavy metals in the surface sediments of the Laizhou Bay were determined and their distributions,sources and pollution status were discussed.The average concentrations of Cu,Zn,Pb,Cd,Ni,Cr,As and Hg are 13.3,59.4,20.2,0.081,57.1,19.4,13.1 and 0.053 mg/kg,respectively.In the EW direction the Cu,Zn,Pb,Cd,Ni,Cr and Hg tend to decrease gradually from the coast toward the center of the bay.In the north of the bay the concentrations of the heavy metals are generally higher than those in the south.The analysis of enrichment factors(EFs) indicates that the Cu,Zn,Cd,Cr and Ni are not enriched and they are mainly derived from the natural weathering of rocks.The As and Pb are moderately enriched and their concentrations are influenced by both the natural and the anthropogenic sources.The Hg is derived chiefly from the anthropogenic sources.The ecological risk analysis shows that the concentrations of As(at all sites) and Ni(at nearly half sites) are both positioned between effect range-low(ERL) and effect range-median(ERM),indicating that they may occasionally cause adverse ecological effects.The concentrations of Cu,Zn,Pb,Cd,Hg and Cr at all sites but site L10 are all lower than ERL,indicating that these metals may almost not cause the adverse ecological effects.At site L10 the concentrations of these metals are positioned between the ERL and the ERM.The environmental quality of the sediments in the northwestern and outer areas of the Huanghe River estuary is relatively bad,which should be paid much attention to.