Analysis On Water Quality Characteristics And Water Ecological Compensation Standard In Xiangjiang River Basin

In recent years,with the rapid economic development and the acceleration of urbanization,the aquatic ecological environment in the Xiangjiang River Basin has been deteriorating,and the public goods attribute of water resources has led to external non-economic phenomena,which has severely restricted the sustainable development of society and economy in the basin.Therefore,the protection of water resources and the establishment of ecological compensation mechanism in the Xiangjiang River Basin have become common aspirations.Based on the monthly observations of 10 water quality parameters at 40 monitoring stations in Xiangjiang River Basin from 2008 to 2016,water quality characteristics were comprehensively evaluated by the water quality index method and multivariate statistical analysis method,and the non-carcinogenic health risks of heavy metals were investigated by the health risk assessment model.On this basis,a compensation standard model based on pollution loss and one-dimensional water quality model was designed and then employed to calculate the compensation standard for adjacent administrative districts in Xiangjiang River Basin.The main research results and conclusions are as follows:?1?In terms of trends,water pollution in Xiangjiang River Basin was relatively serious in 2008-2013,and improved significantly after 2014.The decreasing trend of pollutant concentration was mainly distributed in Yongzhou City,while the increasing trend was primarily in Xiangtan and Changsha City.In spatial,water pollution was mainly clustered in Chenzhou,Xiangtan and Changsha City.In addition,most environmental variables,except Pb and Hg,exhibited significant spatial variations using One-way ANOVA method.In temporal,most of the water quality indicators presented relatively greater composition in the non-flood season,and lower level in the flood season,which is consistent with the pattern of pollutants changing with season.?2?The results of water quality evaluation based on WQI indicated that the main pollutants in Xiangjiang River Basin were Hg,Pb,TP,NH₃-N and COD_Mn,among which NH₃-N was the most polluted.According to the significance test results?p<0.1?,the proportion of secondary industry output value played a great role in basin water quality.?3?Sources of health risks revealed that children were at greater risk than adults and more sensitive to heavy metal pollution.The HQ_ing?hazard quotient by ingestion?was higher than the HQ_derm?hazard quotient by dermal?for both adults and children.Pb,Cr and Cd exhibited the major contribution towards the non-carcinogenic risk and were the primary pollutants in Xiangjiang River Basin,which should be considered as the main target of water quality management and control.Trends of health risks implied an increase from 2008 to 2011,and reached the peak value in 2012,with a lower health risk and relatively slight change in the past year or two.Spatial distribution of health risks suggested that the non-carcinogenic risk was mainly distributed in Hengyang,Xiangtan and Changsha City.?4?The calculation results of economic loss from water pollution manifested that pollution loss was the largest in Xiangtan-Changsha section,followed by the Loudi-Xiangtan section and the Chenzhou-Hengyang section,and the smallest loss was in Changsha-Yueyang section.The calculation results of eco-compensation standard indicated that the final compensation amount in Xiangjiang River Basin in 2016 was as follows:Hengyang compensated Yongzhou0.755 million yuan;Hengyang compensated Zhuzhou 2.508 million yuan;Xiangtan compensated Zhuzhou 2.572 million yuan;Changsha compensated Xiangtan 9.807 million yuan;Changsha compensated Yueyang 1.681 million yuan;Chenzhou compensated Hengyang 4.761million yuan;Zhuzhou compensated Hengyang 0.567 million yuan;Loudi compensated Xiangtan 3.974 million yuan;Hengyang compensated Shaoyang 1.610 million yuan.