Spatio-temporal data mining and modeling: distribution pattern and governance input efficiency of heavy metal emission in industrial wastewater, China

Heavy metal (HM) in industrial wastewater has been one of the serious environmental issues in China for a long time. This paper analyzes the distribution of HMs and governance input efficiency in industrial wastewater based on the archival data of China Statistical Yearbook on Environment from 2001 to 2014. The empirical analysis shows that the concentrations of Hg, Cd, Pb, As, and Cr(VI) generally decreased from 2001 to 2014. The emissions of Hg, Cd, Pb, and As are mostly concentrated in the central provinces (i.e., Hunan, Hubei, Jiangxi), the southern provinces (i.e., Guangxi and Guangdong), and the northern provinces (i.e., Gansu and Inner Mongolia). The distribution pattern is closely related to local industry due to resources dependence, such as mining and processing of non-ferrous metal ores, smelting and pressing of ferrous or non-ferrous metals. Cr(VI) is mainly located in the eastern coastal provinces, including Zhejiang and Jiangsu, and caused by manufacturing industries such as automobile, metal products, leather, fur, feather and related products, and footware. Furthermore, we find that the annual expenditure on and the capacity to deal with industrial wastewater play significant negative effects on reducing HM concentrations in industrial wastewater.