湛江观海长廊红树林湿地土壤重金属污染现状及生态风险评价

摘要

This study is based on the Sea Promenade mangrove surface wetland soil in order to deter-mine the content of 1 1 kinds of heavy metals,and the results show that the average values of the contents of heavy metal elements like Cd,Cu,Co,Hg and Zn much more than the averages of the environmental background values.For examples,the average values of the Hg,Zn,Cu,Cd and Co elements are respec-tively 4.70 times,4.44 times,4.43 times,2.44 times of the environmental background values.This five main heavy metal element content in a different point (such as GHCL4,GHCL6,GHCL7 and GHCL8) exceed the national standards for soil environmental quality level.Other 6 kinds of heavy metal element content like As、Cr、Ni、Pb、V、Mn does not exceed the average environmental background values and the national standards for soil environmental quality level.By adopting evaluation method of potential ecologi-cal risk index method,it is found that the heavy metal contents in the surface soil of Sea Promenade of mangrove wetland can be determinate as strong pollution,among which the potential ecological risk lies in Hg which is identified as very strong pollution.Cd is identified as strong pollution;while other 9 kinds of metal elements like As,Co,Cu,Mn,Cr,Ni,Pb,V,Mn are regarded as slight pollution.Soil heavy metals mainly comes from Zhanjiang harbor ship traffic exhaust gases from the burning of fuel oil,marine paint drops and the production and sewage discharge of urban residents and the enterprise and the pollution from the seaside park and its port.%本研究通过对观海长廊红树林湿地表层土壤11种重金属进行含量的测定,结果显示观海长廊Cd、Cu、Co、Hg、Zn五种重金属元素含量的平均值均超过环境背景值,其中 Hg、Zn、Cd、Cu和Co的平均值分别是环境背景值的4.70倍、4.44倍、4.43倍、2.44倍、1.14倍；这五种主要重金属元素含量在个别样点(如 GHCL4、GHCL6、GHCL7、GHCL8)超过国家土壤环境质量一级标准；As、Cr、Ni、Pb、V、Mn 6种重金属元素含量的平均值未超过环境背景值和国家土壤环境质量一级标准.通过采用潜在生态风险指数法的评价方法进行分析发现,观海长廊红树林湿地表层土壤重金属总体上属于强污染,其中潜在生态风险较大的是元素 Hg,属于很强污染；元素Cd,属于强污染；As、Co、Cu、Cr、Ni、Pb、V、Mn 9种金属元素属于轻微污染.土壤重金属主要来自湛江港船舶行驶燃料油燃烧产生的废气、船舶涂料掉落、城市居民和工业企业排放的污水、附近海滨公园及其码头人类活动带来的污染等.