汉沽养殖区海水重金属含量分布特征及潜在生态危险评价

The Distribution and Potential Ecological Risk of Heavy Metals in Seawater from Hangu Aquiculture Area

[目的]了解汉沽养殖区域海水水质状况及潜在生态危险。[方法]分期采集养殖场海水样品,分析海水中Cr、Ni、Cu、Zn、As、Cd、Pb 7种有害重金属含量,研究其时空变化特征,并采用综合指数法评价其污染程度。[结果]Cr、Ni、Cu、Zn、As、Cd、Pb的含量范围分别为4.75~28.07、2.75~7.82、11.71~17.22、69.99~225.98、4.56~11.88、0.04~0.33、0.08~0.38μg/L。Cr、As、Cd、Pb的单项污染指数和综合污染指数均小于1.00,这4种重金属元素含量均符合国家一类海水水质标准;Ni超标1.22~1.56倍,符合二类海水水质标准;Cu超标2.34~3.44倍,符合三类海水水质标准;Zn超标3.50~11.30倍,符合四类海水水质标准。Cr、Zn、Ni、Cd均呈现出7月含量最高,12月最低的变化趋势;Cu和Pb在9月的含量远高于其他月份;As在9月和12月含量均较高。[结论]汉沽养殖区海水重金属含量的污染程度不具有生态风险性,养殖环境良好。

[Objective] To grasp the seawater quality and the potential ecological risk in Hangu Aquiculture Area.[Method] Seawater samples were collected from aquiculture farm at different times. The contents and distribution of heavy metals（ Cr,Ni,Cu,Zn,As,Cd and Pb） in seawater were studied. The pollution level was evaluated with water quality index（ WQI） model.[Result]Contents of Cr,Ni,Cu,Zn,As,Cd and Pb in seawater ranged within 4. 75- 28. 07,2. 75- 7. 82,11. 71- 17. 22,69. 99- 225. 98,4. 56- 11. 88,0. 04- 0. 33 and 0. 08- 0. 38 μg/L,respectively. The single pollution index of the four heavy metals（ Cr,As,Cd and Pb） and the comprehensive pollution indexes（ WQI） at all stations were less than 1. Its concentrations were all less than the value of the first-grade seawater standard. Ni was 1. 22- 1. 56 times of the seawater standards,which accorded with the second-grade seawater standard. Cu was 2. 34- 3. 44 times of the seawater standards,which accorded with the third-grade seawater standard. Zn was 3. 50- 11. 30 times,which accorded with the fourth-grade seawater standard. Cr,Zn,Ni and Cd showed the highest contents in July and the lowest in December. Cu and Pb concentrations were higher in autumn than other months. As content was higher in September and December.[Conclusion]Pollution degree of seawater heavy metal in Hangu Aquiculture Area has no ecological risk,and the breeding environment is relatively good.