Previous studies have indicated that soil heavy metals (HMs) contaminating the surrounding of mining areas mainly emanates from industrial emissions. Research on the quantification of specific risks from various sources is still lacking. Researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences have investigated the soil HMs contamination and pollution sources in a typical coal industrial city. They quantified the ecological and human health risks of soil HMs from different sources by using a comprehensive approach combining risk assessments with positive matrix factorization (PMF) model.
The study was performed in the core areas of the Yongcheng which is a coal-mining city in eastern Henan Province. Thirty soil samples were collected and analyzed for six HMs (Cu, Ni, Pb, Cd, As, and Hg). The researchers found that the average concentrations of HMs exceeded the corresponding background values and the study area was moderately contaminated by soil HMs HMs pollution was higher for soils in urban area than soils suburban area.
The specific contributions of four sources, it includes natural source, traffic emissions, agricultural practices and industrial activities. These were apportioned as 27.7%, 33.4%, 16.2% and 22.7%, respectively. The source profiles of potential ecological risks vary in urban and suburban areas. Industrial activities are leading contributions in the urban areas. Agricultural practices contribute mainly to suburban areas.
The non-carcinogenic and carcinogenic risks of children were higher than those of adults. While the contributions of human health risk from different sources were very similar between the two groups. Sources from traffic emissions and natural origin mainly contributed to the non-carcinogenic and carcinogenic risks in the study area.