Study on the variation mechanism of Zn isotope in polluted farmland soil.

Zn isotope can help to clarify the migration, transformation and source contribution of Zn in farmland soil. However, the research on Zn isotope value of different end members in farmland soil is incomprehensive, and the variation of Zn isotope in farmland soil caused by different factors in different polluted areas is unclear, which hinders the usage of Zn isotope tracing method in farmland soil. Thus, a Pb-Zn mine polluted farmland in southwest China was selected as the research object and the end elements and farmland soil samples with different Zn contamination were systematically collected to analyse Zn content, fraction and isotopic composition. The effects of different end members and processes of eluviation, organic adsorption and inorganic adsorption on Zn isotopic composition in soil were analysed, and the relationship between these three processes and environmental variables was analysed to clarify the change mechanism. The results can enrich the fractionation mechanism of Zn isotopes, expand the application of Zn isotope in tracing the sources, and provide geochemical evidence for remediation of Zn pollution in farmland soil.