The transfer and driving factors of industrial embodied wastewater in China's interprovincial trade

Currently, interprovincial trade and the industrial division of labor in China are rapidly developing. The end users of products are not responsible for their wastewater discharge but indirectly transfer their own wastewater discharge to production locations through trade flows. This undoubtedly exacerbates the burden of environmental governance at production locations and results in the unreasonable sharing of discharge reduction responsibility between production and consumption areas of products. Studies that focus on the embodied wastewater transfer caused by interprovincial trade and its drivers are important for the formulation of equitable emission reduction targets and environmental policies. Therefore, based on the multiregional input-output (MRIO) model and structural decomposition analysis (SDA), this paper analyzes the transfer and driving factors of industrial embodied wastewater in interprovincial trade in China at the interprovincial and industrial sector levels. The results demonstrate that the transfer volume of industrial embodied wastewater increased from 5,423,884,700 tons in 2012 to 6,343,801,700 tons in 2015 in Chinese interprovincial trade, at a growth rate of 16.96%. The regions with industrial embodied wastewater net outflows were mainly located in eastern regions with a more well-developed manufacturing industry such as Shandong and Jiangsu, the net inflow areas were mainly concentrated in central and western regions such as Chongqing, Sichuan and Yunnan. From the perspective of the industrial sector, the chemical industry, papermaking and printing and manufacturing industry of cultural items, education resources and sports goods, and food manufacturing and tobacco processing industry were the three key sectors regarding the inflow and outflow of embodied wastewater in trade. Through SDA, it was found that the growth of the economic scale was the main reason for the outflow of industrial embodied wastewater in the various provinces. The technology effect imposed a negative influence on the transfer of industrial embodied wastewater in most provinces, especially in Henan and Guangxi. In the short term, technology improvements can be employed to reduce the transfer volume of industrial embodied wastewater, but in the long term, industrial structure optimization and upgrading are required to reduce the discharge and transfer of industrial embodied wastewater. Therefore, to reduce water pollution and control industrial wastewater discharge, it is necessary to consider the transfer and main driving factors of embodied wastewater caused by interprovincial trade when assigning environmental governance responsibilities to each province.