Guan'gai paishui xuebao (Jun 2021)

The Relationship between Nonpoint Agricultural Pollutants and Surface Water Quality in China

  • GAO Fu,
  • FENG Di,
  • SUN Chitao,
  • ZHANG Jingmin

DOI
https://doi.org/10.13522/j.cnki.ggps.2020366
Journal volume & issue
Vol. 40, no. 6
pp. 119 – 124

Abstract

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【Objective】 The purpose of this paper is to analyze the effects of contaminants originating from non-point agricultural pollution on surface water quality in China, in attempts to provide a baseline to help improve surface water management across the country. 【Method】 The analysis was based on surface water quality index (WQI) and four main nonpoint agricultural pollutants: chemical fertilizers, chemical oxygen demand related to poultry industry and livestock (COD), total phosphorus (TP) and ammonium nitrogen (NH4+-N), measured from 1999 to 2018 across the country. These data were used to analyze the correlation between WQI and each of the four pollutants. 【Result】 All four agricultural pollutants increased first and followed by decline or stabilization as time moved from 1999 to 2018. Compared with their contents in 1999, chemical fertilizer, COD, TP and ammonium in the surface water in 2018 increased by 37.1%, 21.1%, 28.4% and 15.6%, respectively. The water quality of most rivers had deteriorated until 2006, but it has seen significant improvement since then. The WQI of most rivers in 2018 improved by 13.8% compared to that in 1999. The water quality of lakes and reservoirs showed significant inter-annual fluctuation, and their WQI in 2018 increased by 6.5% and 2.4%, respectively, compared to that in 1999. It was found that COD, TP and NH4+-N originating from livestock and poultry industry were negatively correlated with WQI of rivers at significant level. Across the country, TP impacted river WQI most, followed by NH4+-N, with COD being the least. 【Conclusion】 Water quality in rivers across China has improved over the past few years, but the water quality of reservoirs and lakes remains largely unchanged. Reducing fertilizer application and disposal of wastes from livestock and poultry industry is critical to improving surface water quality and should be the main target in reducing agricultural pollution and improving surface water quality.

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