白龟山水库规划区污染特征及潜在生态风险评价

Contamination Characteristics and Potential Ecological Risk Assessment of Planning Areas in Baiguishan Reservior

分析了白龟山水库及其入库河流水体和沉积物中TN,TP,有机质和Cd,Pb,Cr,Cu,Zn,Mn,Ni等7种重金属的含量及分布特征,并结合地积累指数法和HANKANSON生态危害指数法对沉积物重金属的累积效应和潜在生态风险进行评价.结果表明:白龟山水库规划区内水库及河流水体主要污染物为TN和TP,其中鲁山污水厂出口断面严重超标,ρ(TN)和ρ(TP)高达《国家地表水环境质量标准》(GB3838—2002)Ⅱ类水质标准的46.4和22.1倍;w(TN),w(TP),w(Cd),w(Pb),w(Cr),w(Cu),w(Zn)与w(OM)呈显著正相关,而w(Mn)和w(Ni)与w(OM)的相关性不显著;鲁山污水厂出口沉积物重金属的生态危害最大,RI为241.13,为中等生态危害,以Cd和Cu的生态危害为主,特别是Cd作为最主要的生态风险贡献因子,应适当引起重视.

Concentrations and distribution characteristics of total nitrogen （TN） , total phosphorous （TP）, organic matter （OM） , and seven kinds of heavy metals-cadmium （Cd）, lead （Pb） , chromium （Cr）, copper （Cu）, zinc （Zn）, manganese （Mn）, and nickel （Ni） -in the Baiguishan reservoir, its major input rivers and sediments were analyzed. The accumulation effects and potential ecological risks of the heavy metals in the sediments of Baiguishan reservoir and major input rivers were evaluated by applying geoaccumulation index and Hankanson ecological risk index methods. The results demonstrated that TN and TP Were the major pollutants in the water of the reservoir and rivers within the water source planning area, especially the outfall water of Lushan sewage plant, in which concentrations of TN and TP respectively reached up to 46. 4 times and 22. I times the Secondary Environmental Quality Standard for Surface Water （GB3838-2002）. Significantly positive correlations between TN, TP, Cd, Pb, Cr, Cu, Zn and OM contents were found, whereas correlations were not significant between Mn, Ni and OM contents. The ecological risk hazard of heavy metals in sediments of Lushan sewage plant outfall district was the highest, with RI degree of 241.13, reaching the middle ecological risk hazard level. The ecological risk was dominated by Cd and Cu, particularly Cd, as the most important contributing factor, to which more attention should be paid.