Environmental assessment of closed greenhouse vegetable production system in Nanjing, China

There is growing concern about vegetable safety and environmental contamination resulting from rapid development of greenhouse vegetable production in China. This paper presents an integrated study of the quality of soils, vegetables, fertilizers, water, and sediments and indicates the characteristics of primary pollutants such as N, P, and some heavy metals in soils using the spatial analysis. Furthermore, sources of soil pollutants were analyzed combining principal component analysis and vertical mobility results. Also the environment risk was evaluated on greenhouse vegetable production activities in a closed greenhouse vegetable production system in Nanjing City, China. Greenhouse vegetable fields, which applied more fertilizers than greenhouse strawberry fields, had serious accumulations of soil N, P, Cd, Cu, Pb, and Zn, suggested both by principal component analysis and vertical mobility results. This accumulation resulted in high Cd in some vegetables and high concentrations of N and P in irrigation water and groundwater. The result of spatial analysis showed the northwest and north-center regions which featured convenient transportation and irrigation water were the hotspots for pollutant accumulation. Concentrations of pollutants decreased from these regions to the periphery gradually; results further supported by correlation analysis. The environmental management of this kind of production system should pay more attention to supervising and controlling the quality of agriculture inputs and improving the efficiency of fertilizer. Producers should utilize the soil appropriately based upon the environmental risk associated with different media. Finally, soil properties and plant species should be considered in the future when assessing soil environmental quality.