LAUSR

The three types of elements nitrogen (N), phosphorus (P) and Sulfur (S) are inextricably linked from the source to the destination throughout the system. To analyze the environmental load caused by the three elements, this study established a material metabolism model to quantify the relationships among metabolic processes on the provincial scale and examined their environmental implications based on Substance Flow Analysis (SFA). The results show that the metabolic fluxes of nitrogen, phosphorus and sulfur in the socioeconomic system of Liaoning Province in 2016 were 5.339 million tons, 0.582 million tons and 3.084 million tons, respectively. The agricultural sector caused the greatest environmental pressures on water bodies, in which nitrogen and phosphorus accounted for 61.8% and 80.2% of the total water body load. For atmospheric load, the nitrogen and sulfur elements in the industrial sector caused the largest atmospheric load, accounting for 37.8% and 91.4% of the total atmospheric load, respectively. The main source of phosphorus soil load in Liaoning Province is the agricultural production, accounting for 85.3% of the total soil load caused by phosphorus.