With the rapid development of industrialization, soil heavy metal pollution has become a global environmental problem. Mercury,as one of the five most toxic environment pollutants, not only affects the normal growth of crops, but also poses a serious threat to the quality and safety of agricultural products. Soil pH is one of the most important factors affecting mercury migration and transformation. The mechanism of interaction between soil pH and mercury has become a focus of environmental science research in recent years. Therefore, this paper summarized the source, hazard and forms of mercury in soil, and the mechanism of the effect of soil pH on mercury migration and transformation was elaborated from the aspects of mercury bioavailability and migration and transformation process. Several conclusions were drawn based on these analyses. Acidic conditions might increase the amount of available mercury, resulting in increase of mercury bioavailability and migration capacity. Adsorption-desorption of mercury was greatly affected by the soil pH. The effects of soil pH on complexation-chelation reaction, redox reactions and methylation reaction in mercury migration and transformation were reflected in ion competitive adsorption, valence change and methylation-promoting factor synthesis, respectively. In addition, the further research of mercury was proposed, which could provide reference for the remediation of mercury contaminated soil and the establishment of mercury pollution diffusion model.
Journal of Agricultural Resources and Environment