Multi-pollutant based grey water footprint of Chinese regions

Abstract Grey water footprint (GWF) is an essential indicator describing the effects of aquatic pollutants on water quantity, which is significantly influenced by interregional trade. Existing studies on the impacts of interregional trade on GWF in China have deviations. That is, traditional GWF is determined by the pollutant with the highest pollutant-specific GWF, but overlooks the influences of coexisting compounds. Coexisting compounds have large influences on GWF quantification. However, the impacts of interregional trade on the improved GWF in China have not been well characterized. This study integrates the multi-regional input-output analysis and an improved GWF quantification method considering multiple pollutants, to investigate the impacts of interregional trade on the GWF in China. Compared with traditional GWF, the improved GWF of Chinese regions decreases by 19-35%. Up to 35% of China's improved GWF is related to commodities that are produced outside of regions where they are finally consumed. Beijing-Tianjin and coastal regions outsource GWF to the central and northern regions. Sectors contributing the most to GWF outsourcing include corn, cattle, swine, poultry, and other animal husbandry. This study provides more accurate region-specific and sector-specific results for policy decisions on water resource conservation in China.