Model-based spatio-temporal cadmium health risk assessment by rice consumption and management at regional scale in...

Cadmium (Cd) accumulation in agricultural soils and its transfer to crops pose significant health risks to humans. To identify high-risk areas and guide regional management, this study conducted a spatio-temporal assessment of Cd fluxes and pollution risks in rice systems, based on a systematic 5-year survey (2014-2019) in a typical agricultural county in southern China. The model accurately simulated historical changes in soil total Cd content across 56 paddy sites, with an average annual increase of 3.4 μg kg⁻¹ . Atmospheric deposition contributed 63 % of total soil Cd inputs and crop harvesting accounted for 56 % of total outputs, with 25 % of the rice area currently exceeding the national food safety standard. If no mitigation measures are taken this area would increase to 74 % by 2070, with over 87 % of farmlands falling into Cd pollution risk zones. Rice from 52 % of the farmlands would pose non-carcinogenic health risks to the surrounding population. The risks are particularly high in the eastern and western regions, with children (56 %) being more affected than adults (48 %) due to greater Cd intake. To mitigate further Cd pollution, targeted Cd source control areas and improvement of soil properties are essential. The study demonstrates the potential of a site-specific dynamic Cd pollution model to assist decision makers in formulating policies to reduce Cd pollution at regional level.