基于环境基尼系数的洞庭湖区水污染总量分配

摘要

从社会、经济和自然资源系统的整体效益出发,构建了基于基尼系数的水污染负荷公平分配评价指标体系,并且以贡献系数作为判断不公平因子的依据,结合GIS技术分析洞庭湖区不公平因子分布的空间差异性；利用基尼系数最小化模型,制订了洞庭湖区基于公平性的水污染物总量分配方案.研究表明:2008年湖区基于GDP和土地面积的总氮、总磷污染负荷基尼系数均大于0.2,超过了基尼系数合理限值,湖区氮磷排放在经济和自然资源方面存在不公平现象；在湖区3个大型污染控制区中,Ⅰ区(中心城市污染控制区)和Ⅲ区(山地丘陵生态保育区)分别具有最小的氮磷土地面积贡献系数和经济贡献系数,是湖区不公平性特征最为显著的2个区域；在优化分配所得的2020年湖区各单位相对于2008年的总氮排放削减方案中,Ⅰ区削减率最高,达8.18％,岳阳市区削减量最大,为865.0 t/a；在相应的总磷排放削减方案中,Ⅱ区(平原农业综合整治区)削减率最高,达9.45％,华容县削减量最大,为78.45 t/a.%The equitable and reasonable allocation of the total permitted pollution discharge is the key to the load control of the total water pollutant. A specific assessment system of the water pollutant load allocation based on the environmental Gini coefficient method was established by taking the whole benefit of the social, economic and natural resources into account. The spatial distribution characteristics of the unfair factors in the area of Dongting Lake were also analyzed through selecting the contribution coefficient as a judge for unfair factors combined with the GIS technique. Additionally, the program of the total load allocation for water pollutants in the Dongting Lake area was proposed according to the minimized model of Gini coefficient. The research found that Gini coefficients of TN and TP based on both GDP and land area were higher than 0. 2, which was over the reasonable limitation of the Gini coefficient. These higher Gini coefficients implied unfair pollutant discharge in the lake area. In addition, there were unfair features in different parts of the lake area. Among three large pollution control zones, zone Ⅰ (pollution control zone of central cities) and zone Ⅲ (ecological conservation zone of mountains/hills) offered the least land area contribution coefficients and the least green contribution coefficients, respectively, which implied the presence of the most significant unfair features in these two zones. To change the unfair status, the minization of Gini coefficients led to an optimization of pollutant discharge allocation in 2020 based on the data in 2008. In the optimized strategy of the total nitrogen discharge, zone Ⅰ would have the reduction rate of 8. 18% , which would be the largest among all the three pollution control zones. In addition, Yueyang City would have the biggest reduction amount of 865. 0 t/a among all the twenty administrative units in the lake area. For the total phosphorus discharge, zone Ⅱ ( comprehensive improvement zone of plan agriculture) would have the largest reduction rate of 9. 45% , and Huarong County would have the greatest reduction amount of 78. 45 t/a.