流沙湾重金属变化特征与潜在生态风险评价

用ICP-MS对2008年流沙湾海水和沉积物中Cu、Pb、Zn、Cd、Cr等重金属含量进行了测试和分析。结果表明,在所调查的14个站位中,流沙湾水体中Cu、Pb、Zn、Cd、Cr的平均含量分别为(1.94±0.09)μg/L,(0.70±0.06)μg/L,(13.11±0.81)μg/L,(1.16±0.13)μg/L,(2.42±0.03)μg/L;表层沉积物中Cu、Pb、Zn、Cd、Cr的平均含量(10.16±1.34)mg/kg,(62.46±4.42)mg/kg,(86.74±18.65)mg/kg,(0.50±0.03)mg/kg,(22.81±2.80)mg/kg。流沙湾水体中Cu、Zn、Cd含量夏秋季高于冬春季,Pb冬夏季高于春秋季节,Cr含量季节变化不明显;各重金属元素在不同水域含量水平大致相当。表层沉积物中Cu、Pb、Zn、Cr夏季含量高于春季含量;Cu、Pb、Zn等元素在沙嘴处含量较高。生态环境质量评价结果表明,流沙湾水体未受到Cu、Pb、Zn、Cd、Cr等重金属元素的污染,水质优良;流沙湾表层沉积物中Cu、Pb、Cd、Cr和Zn等元素的潜在生态危害轻微。

Variation Features and Potential Ecological Assessment of Heavy Metals in Liusha Bay

The survey and analysis on heavy metals(Cu,Pb,Zn,Cd,Cr) in seawaters and surface sediments of Liusha Bay was carried out with ICP-MS in 2008.Of all 14 stations,the annual average concentrations of Cu,Pb,Zn,Cd and Cr in seawaters were(1.94±0.09) μg/L,(0.70±0.06) μg/L,(13.11±0.81) μg/L,(1.16±0.13) μg/L,(2.42±0.03) μg/L,respectively.The corresponding contents of above metals in surface sediments were(10.16±1.34) mg/kg,(62.46±4.42) mg/kg,(86.74±18.65) mg/kg,(0.50±0.03) mg/kg,(22.81±2.80) mg/kg.In the surveyed waters of Liusha Bay,the contents of Cu,Zn and Cd in summer and autumn were higher than those in spring and winter,while the concentration of Pb was lower in summer and autumn than that in spring and winter.As for the content of Cr,there was no distinct difference in different seasons.All metals in seawaters showed in a similar content level in the inner and outer bay.For surface sediments,the contents of Cu,Pb,Zn and Cr in summer were higher than those in spring.And a higher concentration of Cu,Pb and Zn in surface sediments was found in the narrow mouth of Liusha Bay.According to the results of the ecological environmental quality assessment,the seawater was relatively clean and the heavy metal pollution grade was slight;the potential risks of Cu,Pb,Cd,Cr and Zn were rather low in surface sediments.