Study on Quantification Method for the Risk of Soil-Plant-Human System Environmental Pollution Caused by Sewage Irrigation in Agriculture

摘要

Long-term sewage irrigation can cause accumulation of contaminants in soil, which imposes severe damages to soil and plants and further triggers many chronic diseases in human bodies via the food chain. In this paper, the effect of sewage irrigation on changes in concentration of contaminants in soil and its relationship with the concentration of contaminants in the main agricultural plants are discussed, and a health risk assessment is performed on the contaminant exposure suffered by people in the sewage irrigation area. Based on this, an environmental pollution risk model for the soil-plant-human system was established for research on the acceptable irrigation concentration of contaminants in sewage and the safe service period of sewage irrigation. A practical example adopted in this paper proves that arsenic pollution caused by sewage irrigation to soil-plant-human body system in the irrigation area imposes a comprehensive risk degree of 0.40, the acceptable arsenic irrigation concentration is 0.086mg/L and the safe service period for this irrigation area is 150 years. Thus, the reclaimed water shall be subject to innocuous disposal under scientific guidance for agricultural irrigation.