A study estimated agricultural pollution in the Liaohe River source area from 1999 to 2009. Total pollution from COD, nitrogen, phosphorus, and ammonium nitrogen was around 36,000, 10,400, 1,259, and 4,306 tons per year, respectively. Nitrogen was the biggest pollutant, contributing almost half of all pollutants, with livestock waste being the main source. Livestock pollution was much higher than other sources like farming and aquaculture. Among the areas studied, Lishu, Gongzhuling, Dongliao, and Shuangliao had the most significant pollution levels, making them major pollution hotspots in the region.