A novel approach for soil contamination assessment from heavy metal pollution: a linkage between discharge and adsorption.

Soil protection from heavy metal contamination requires scientific assessment on the linkage between site-specific pollutant discharge and environmental effects. However, this kind of linkage is usually disregarded due to the lack of assessment tools in environmental policies, e.g., some developed coastal cities in China have forced their highly polluting industries out to less developed interior areas without consideration of the impacts from pollution transfer. This paper developed a soil adsorption fraction (SAF) model to characterize the emissions-to-adsorption relationship between heavy metal emission and the adsorption by soil. Case studies were carried out for two adjacent southern cities in China, i.e., Guangzhou and Shaoguan. The results indicated that the average SAF of cadmium was 5.38 x 10(-3) for Shaoguan and 1.28 x 10(-3) for Guangzhou, i.e., cadmium released from Shaoguan threatened the soil environment 4.2 times of that from Guangzhou. Further analysis showed the polluting pathway and abundance of water resources were the main influencing factors on SAF. Soil contamination will be exaggerated by relocating heavy metal polluting industries from coastal areas to interior areas. The results should be useful to prompt site-specific policies on heavy metal pollution control.