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Pollution control

Agricultural Non-Point Source Pollution in Erhai Lake Basin

Strategic Insights

— 1 min read

Agricultural non-point source pollution has emerged as a significant challenge in global water pollution governance, particularly in sensitive areas like the Erhai Lake Basin in western Yunnan Province. The lake has long been under pollution pressure from agricultural activities, with data showing that agricultural sources contributed 40% of major water pollutants in China in 2007. A recent study by researchers led by Professor Wen Xu from China Agricultural University aimed to quantify the emissions of four pollutants - ammonia nitrogen, total nitrogen, total phosphorus, and chemical oxygen demand - from agricultural production and rural domestic sewage in the Haixi area of the Erhai Lake Basin.

Key Takeaways:

  • The annual emissions of the four pollutants in the Haixi area in 2022 were 72.9 t of NH3-N, 264.1 t of TN, 29.2 t of TP, and 1453.3 t of COD, respectively.
  • Rural domestic sewage was the main contributor to NH3-N, accounting for 74%, while crop production was the primary source of TN, accounting for 45%.
  • Livestock and poultry breeding was the main source of TP and COD, accounting for 52% and 71%, respectively, with dairy cows and pigs being the main contributors.
  • Shangguan Town has become a key area for the control of all pollutants, with its livestock and poultry breeding industry being a major source of emissions.
  • Wanqiao Town has the largest crop planting area, making it the town with the highest crop pollution emissions.
  • The southern towns are more significantly affected by domestic sewage, with some pipelines being damaged and untreated sewage directly flowing into the lake.

Statistics:

  • Annual emissions of pollutants in the Haixi area in 2022:

+ NH3-N: 72.9 t

+ TN: 264.1 t

+ TP: 29.2 t

+ COD: 1453.3 t

  • Contribution of different sources to pollutant emissions:

+ Rural domestic sewage (NH3-N): 74%

+ Crop production (TN): 45%

+ Livestock and poultry breeding (TP and COD): 52% and 71%, respectively

  • Distribution of pollutant emissions in Shangguan Town: 21%-44% of total area

Sources:

  • China Agricultural University - DOI: 10.15302/J-FASE-2025622
  • Frontiers of Agricultural Science and Engineering
  • Manual of the Second Pollution Census Correlation Coefficients

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