Innovative Benefit–Risk-Value Assessment for Cadmium and Selenium Coexposure in Black Shale Regions

The coexistence of cadmium (Cd) and selenium (Se) in
black shale
regions poses challenges for assessing health risks in local populations.
Traditional risk assessments focus exclusively on single Cd contamination
and total dietary intake, neglecting the interactions between them
and the digestion and adsorption processes in the human body. This
study established a novel benefit–risk-value (BRV) criterion
to assess coexposure effects. Besides, we compared existing single-element
risk assessment criteria and evaluated changes in risk before and
after the incorporation of bioaccessibility using in vitro simulation.
Rice constituted the major exposure source for Cd, whereas Se intake
primarily relied on meat and rice. Integrating bioaccessibility with
traditional risk assessment criteria significantly reduced the health
risks associated with Cd exposure, while revealing notable Se deficiency
in adults and seniors. Different from traditional models, BRV analysis
indicated that children were safe from Cd and Se exposure, whereas
adults and the seniors suffered from Se deficiency. As a biomarker,
hair further validated the feasibility of the new standard. Correlation
analysis demonstrates an age-dependent decline in the molar ratio
of Se to Cd in hair samples. This study reveals that the mitigation
of Se on Cd toxicity may contribute to Se deficiency.