Controlling Factors and Predictive Models of Total Mercury and Methylmercury Accumulation in Rice (Oryza sativa L.) from Mercury-Contaminated Paddy Soils

It is urgent to detect the major controlling factors and establish predictive models of mercury (Hg) accumulation in rice. A pot trial was conducted, exogenous Hg was added to 19 paddy soils at 4 concentration levels in this study. The major controlling factors of total Hg (THg) in brown rice were soil THg, pH and organic matter (OM) content, while those of methylmercury (MeHg) in brown rice were soil MeHg and OM. THg and MeHg in brown rice could be well predicted by soil THg, pH and clay content. The data from previous studies were collected to validate the predictive models of Hg in brown rice. The predicted values of Hg in brown rice were within the twofold prediction intervals of the observations, which demonstrated the predictive models in this study were reliable. The results could provide theoretical foundation for the risk assessment of Hg in paddy soils.

Automated summary

This study conducted a pot trial to investigate the major controlling factors and establish predictive models of mercury accumulation in rice. The results showed that soil total mercury, pH, and organic matter content were the major factors influencing total mercury in brown rice, while soil methylmercury and organic matter were the major factors influencing methylmercury in brown rice. The predictive models based on soil total mercury, pH, and clay content showed reliable results, which were validated by data from previous studies. The findings of this study can contribute to the risk assessment of mercury in paddy soils.