Study on Non-point Source Pollution Prevention and Control of Water Environment in Tuo River (Chengdu Section)

Currently, effective source monitoring of non-point source pollution for chemical oxygen demand (COD) and total phosphorus has not yet been achieved in China. Among these pollutants, ammonia nitrogen, total nitrogen, and total phosphorus primarily originate from agricultural production activities and domestic wastewater; heavy metals, petroleum hydrocarbons, volatile phenols, and cyanides mainly come from industrial wastewater; while animal and vegetable oils predominantly stem from domestic wastewater. Through model calculations and comparative analysis of monitoring data, it was found that the Tuojiang River (Chengdu section) exhibits high loads of COD, ammonia nitrogen, and total phosphorus from non-point source pollution in its water environment. Small-scale, non-intensive livestock and poultry farming in the agricultural sector contributes significantly to the pollution load. Industrial parks, residential activities, and agricultural cultivation increase the risk of non-point source pollution in the water environment. Therefore, measures should be accelerated, such as improving the construction of sewage collection pipeline networks and raising public awareness of environmental protection. Efforts should also be strengthened to investigate and rectify river discharge outlets, intensify the cleanup and rectification of riverbanks, shoals, and wetland cultivation, and establish riparian buffer zones to minimize non-point source pollution to the greatest extent possible.