环渤海芦苇湿地沉积物重金属污染评价

Assessment of Heavy Metal Pollution in Reed Wetland Sediments around Bohai Sea

滨海湿地位于陆地和海洋交错处的关键带,对污染物的迁移和转化具有十分重要的调控作用。为了解环渤海湿地沉积物中重金属的污染现状及潜在生态风险,文章选取环渤海11个主要芦苇湿地表层(0~20 cm)沉积物为研究对象,对其中Pb、Cr、Ni、Cu、Zn、Cd6种重金属的含量进行分析,并采用多种方法对重金属潜在来源和生态风险进行解析和评价。结果表明,环渤海芦苇湿地沉积物中Pb、Cr、Ni、Cu、Zn、Cd 6种重金属的平均含量分别为(17.92±5.81)、(50.29±20.50)、(31.53±9.71)、(25.37±4.29)、(80.13±15.11)、(0.92±0.54)mg/kg,其中,辽河三角洲湿地Pb、Cd含量最高,黄河三角洲湿地Cu、Ni、Cr含量最高,七里海湿地Zn含量最高。内梅罗综合污染指数法、地累积指数法和单因子潜在生态危害指数法的结果都表明Cd在环渤海湿地污染较严重,其他重金属污染程度较低。同时,辽河三角洲湿地和黄河三角洲湿地由于存在油田采油活动和湿地水产养殖,并且沉积物p H相对较低,是引起该地区重金属污染水平明显高于渤海湾滨海湿地的原因。因此,环渤海芦苇湿地,尤其是辽河三角洲湿地和黄河三角洲湿地,需要重点关注重金属Cd的潜在生态环境风险。

Coastal wetland is located in the critical zone where land and ocean intersect and plays a very important role in regulating the migration and transformation of pollutants.In order to understand the pollution status and potential ecological risks of heavy metals in sediments of wetlands around the Bohai Sea,surface layer(0~20 cm)sediments of 11 major reed wetlands around the Bohai Sea were selected as research objects.The contents of Pb,Cr,Ni,Cu,Zn and Cd were analyzed,and the potential sources and ecological risks of heavy metals were analyzed and evaluated by various methods.The results showed that the average contents of Pb,Cr,Ni,Cu,Zn and Cd were(17.92±5.81)mg/kg,(50.29±20.50)mg/kg,(31.53±9.71)mg/kg,(25.37±4.29)mg/kg,(80.13±15.11)mg/kg,(0.92±0.54)mg/kg respectively.Among them,Pb and Cd contents are the highest in Liaohe Delta wetland,Cu,Ni and Cr contents are the highest in Yellow River Delta wetland,and Zn contents are the highest in Qilihai wetland.Nemerow comprehensive pollution index method,ground accumulation index method and single factor potential ecological damage index method all showed that Cd pollution was serious in Bohai Rim wetland,and other heavy metals pollution was low.At the same time,the heavy metal pollution level of Liaohe Delta wetland and Yellow River Delta wetland is significantly higher than that of Bohai Bay wetland due to the existence of oil extraction activities and wetland aquaculture,and the relatively low pH of sediment.Therefore,the potential ecological and environmental risks of Cd should be paid more attention in the reed wetlands around the Bohai Sea,especially in the Liaohe River Delta and the Yellow River Delta.