汶川地震极重灾区震后10年环境承载力评估

采用大气污染物超标指数、水污染物浓度超标指数、污染物浓度综合超标指数等3个指标,针对汶川地震极重灾区10个县市,评价了区域环境系统对社会经济系统的支撑能力。结果表明:10个县市中,环境承载力超载的县市有7个,接近超载的县市有3个。其中,9个县市的大气存在环境质量问题,4个县市的水环境质量存在问题,整个区域大气环境质量改善形式更为严峻。10县市的大气污染物中,O₃、PM_2.5、PM₁₀普遍超标或接近超标,是影响区域大气质量的主要因素。在3指标中,又以PM₁₀和PM_2.5超标情况最为严重。大气污染在10个县市中具有明显的区域特征。都江堰市、彭州市、安县、绵竹市、什邡市等环成都城市圈的5县市大气污染物浓度超标指数普遍高于远离成都经济中心的5县市。根据影响水质的水污染物性质,及水环境影响因子排序分析,彭州市、什邡市在COD_Cr、P、N-NH₃上有较高载荷,平武县在CODMn、DO两因子上载荷较大;汶川县的主要水环境影响因子是BOD5。根据在水污染因子上的载荷,10县市水污染特征归为集中污染型和面源污染型,以及混合污染三种类型。

Evaluation of Environmental Carrying Capacity in the Severest Disaster Area Ten Years after Wenchuan Earthquake

For 10 counties(cities)in the severely affected areas of the Wenchuan earthquake,three indicators including the air pollutant exceeding standard index,water pollutant concentration exceeding standard index,and pollutant concentration exceeding standard index were used to evaluate the regional environmental system's support capacity for the social and economic system.The results showed that among the 10 counties(cities),there are 7 counties(cities)with overloaded environmental carrying capacity and 3 counties(cities)near overload.There are environmental quality problems in the atmosphere of 9 counties(cities),and there are problems in the water environment quality in 4 counties(cities),indicating that the improvement of atmospheric environmental quality in the entire region is more severe.Among the air pollutants in 10 counties(cities),O₃,PM_2.5,and PM₁₀ generally exceeded or were close to exceeding standards,which are the main factors affecting regional air quality.Among the three indicators,PM₁₀ and PM_2.5 are the most serious indicators.Air pollution has obvious regional characteristics in 10 counties(cities).The air pollutant concentration exceeding index in the 5 counties(cities)surrounding the Chengdu city circle,such as Dujiangyan,Pengzhou,Anxian,Mianzhu,and Shifang,is generally higher than that of 5 counties and cities far from the economic center of Chengdu.According to the nature of water pollutants that affect water quality and the ranking analysis of water environmental impact factors,Pengzhou and Shifang have higher loads on COD_Cr,P,N-NH₃,and Pingwu County has higher loads on CODmn and DO.The main environmental impact factor of Wenchuan is BOD5.According to the load of water pollution factor,the water pollution characteristics of the 10 counties(cities)are classified into three types which are concentrated pollution,non-point source pollution,and mixed pollution.