Water Pollution Impact Assessment of Beijing from 2011 to 2015: Implication for Degradation Reduction

Abstract

Water resource is an essential element for all lives on this planet. With the rapid growth of the economy, urban population, as well as the changes of land use, water degradation issues are becoming more severe. Beijing, as the capital and one of the megacities of China, faces the issue of water degradation. To investigate the water degradation variations of Beijing, the present study has determined the water degradation impacts of the major pollutants, regarding water eutrophication, acidification, and ecotoxicity, and used the cumulative water degradation potential (WDP) curves to effectively identify the most critical pollutants for water degradation reduction. The results show that: (1) The water eutrophication fluctuated at around 9,500 kt COD_eq from 2011 to 2015, and phosphorus (P) is the critical pollutant for monitoring eutrophication reduction. (2) The water ecotoxicity decreased during this period, and reduced dramatically from 2013 to 2015, with a reduction rate up to 91 %. This dramatic change is related to the reduction of coal consumption and steel production. Hg and Cd are identified as the two most critical pollutants for ecotoxicity reduction. (3) The water acidification decreased gradually from 229.71 kt SO_2eq to 167.51 kt SO_2eq, with a decrease rate of 27 %. SO₂ is the most critical pollutant for acidification reduction. In conclusion, the overall water degradation decreased during this period, by 1.5 % for water eutrophication, 27 % acidification and 90 % for ecotoxicity. Phosphorus (P), SO₂, Cr, and Hg are the most important pollutants for water degradation reduction of Beijing.