广西北部湾沉积物重金属污染特征及生态风险评价

Evaluation on sediment pollution and potential ecological risks in Guangxi Beibu Gulf

于2018年夏季采集了广西北部湾表层沉积物样品,分析沉积物中6种重金属(Cu、Pb、Zn、Cd、Hg和As)含量的分布特征,利用数理统计方法研究其来源及主控因素,并评价了重金属的总体污染状况和潜在生态风险.结果显示,北部湾沉积物中Cu、Pb、Zn、Cd、Hg和As浓度的平均值分别为11.16、18.9、27.8、0.06、0.030、3.73μg·g^(−1).不同重金属含量的分布呈现区域性的差异,但其来源主要受到近海人类活动的影响.与其他区域相比,北部湾沉积物重金属含量处于较低水平,但明显高于北部湾历史监测值,表现一定程度的富集.北部湾沉积物重金属含量均符合Ⅰ类沉积物标准,单因子污染影响程度依次为Cu>Pb>As>Zn>Hg>Cd,总体处于低程度污染.除了Hg处于中等潜在生态危害程度外,其他重金属潜在生态危害程度低,生态危害影响依次为Hg>Cd>As>Cu>Pb>Zn,Hg对海域环境污染及潜在危害影响程度最高.

The distribution characteristics of the concentration of Cu,Pb,Zn,Cd,Hg and As were analyzed based on the geochemical analisis of surface sidement samples in Guangxi Beibu Gulf.The sources,main controlling factors and the potential ecological risks for heavy metal distribution were discussed in this study.The results showed that the average concentrations of Cu,Pb,Zn,Cd,Hg and As were 11.16,18.9,27.8,0.06,0.030,3.73μg·g^(−1),respectively.The distribution of different heavy metals showed regional differences,but their sources were mainly affected by human activities in the coastal area.Compared with other areas,although the heavy metals in the sediments of Guangxi Beibu Gulf were at relatively low level,those level in the gulf were significantly higher than that historical monitoring level.The level of heavy metals in the sediments of Guangxi Beibu Gulf reached China’s national first-class benchmark of marine sediment quality,and the degree of pollution for six metals were arranged in the following order:Cu>Pb>As>Zn>Hg>Cd,and caused low levels of pollution generally.Except for the medium potential ecological risk of Hg,other metals were at a low ecological risk level,and the order for the ecological risk of the six metals was Hg>Cd>As>Cu>Pb>Zn,and Hg was the primary potential ecological risk factor.