北部湾潮间带沉积物中重金属和多氯联苯的分布特征及生态风险评价

选择北部湾9个典型采样点,研究了潮间带沉积物中重金属和多氯联苯(PCBs)的分布特征和生态风险.分析结果表明,Hg、As、Cu、Pb、Zn、Cd、Cr等重金属和总PCBs的平均含量分别为0.100、10.00、19.89、45.97、208.65、0.098、17.86 mg.kg-1和1.48!g.kg-1.重金属和PCBs表现出不同的空间变化规律.相关性分析表明,北部湾潮间带的重金属主要来自人为污染;沉积物的粒度参数和有机质含量等性质特征是影响PCBs分布和迁移的重要因素;重金属和PCBs总量之间不存在明显的相关性.生态风险评价结果表明,PCBs和Cd是北部湾潮间带最主要的生态风险因子,Zn和PCBs是优势污染物;研究区域总体处于中等生态风险等级,表明沿岸港口和临海工业等人为活动已经对北部湾滨海地区造成了一定的环境压力.

Distribution and ecological risk assessment of heavy metals and polychlorinated biphenyls in the intertidal sediments along the Beibu Bay

The contents of heavy metals and polychlorinated biphenyls(PCBs) in the sediments from 9 sampling sites in the intertidal zone along the Beibu Bay were examined.The average contents were 0.100,10.00,19.89,45.97,208.65,0.098,17.86 mg · kg-1 for Hg,As,Cu,Pb,Zn,Cd,Cr and 1.48 μg · kg-1 for total PCBs,respectively.These contaminants presented different spatial variations.Correlation analysis indicated that heavy metals in the intertidal sediment along the Beibu Bay originated mostly from human activities,and the characteristic of sediment such as grain size distribution and organic carbon content were important factors that influence distribution and migration of PCBs.The results also showed that the contents of heavy metals have no significant correlation with that of total PCBs.The ecological risk assessment indicated that PCBs and Cd were the uppermost ecological risk factors in the intertidal zone along the Beibu Bay,while Zn and PCBs were the priority pollutants.The overall ecological risk of the study area was at middle level.It could be concluded that anthropogenic activities such as shipping and industrial activities have already caused environmental pressure on the coastal area of the Beibu Bay.