Relative bioavailability of cadmium in aquatic products and its application on the cadmium exposure risk assessment

Abstract

ObjectiveTo understand the relative bioavailability （RBA） of cadmium in different aquatic products. Based on the consideration of the gender differences and the relative bioavailability of cadmium in different foods， the physiologically based toxicokinetic （PBTK） model of cadmium was further optimized and verified. The correlation between internal and external exposure in quantitative risk assessment of food safety was optimized， and the provisional tolerable daily intake （PTDI） value of cadmium was derived.MethodsThe relative bioavailability of cadmium in different aquatic products was determined in four-week-old Balb/c female mice. The PBTK model of cadmium metabolism was optimized by ABC-MCMC method using combined internal and external exposure data of cadmium in Shanghai residents， and the PTDI was calculated accordingly.ResultsExcept for scallops and squid， the RBA of aquatic samples was less than 1， indicating that the absorption rate of cadmium in aquatic products was lower than that of cadmium chloride. The higher RBA of squid and scallop may be due to the presence of cadmium in the visceral organs， which is conducive to cadmium absorption and its higher concentration of cadmium. Frying at the temperature less than 160 ℃ reduced cadmium absorption but may increase cadmium absorption at the temperature greater than 160 ℃. The optimized model parameters converged well and the model could reasonably estimate urinary cadmium level according to the external exposure of cadmium. The PTDI value was 0.466 4 μg·（kg·day）-1 according to the optimized single-chamber model.ConclusionThe relative bioavailability of cadmium in different foods varies greatly， except for squid and scallops， RBA is less than 1， and cooking processing will affect the RBA of food. The construction of the PBTK model did not only consider the effects of gender differences on cadmium metabolism， but also included the relative bioavailability data to optimize and adjust the correlation coefficient of absorption rate. Compared with the model without RBA adjustment， the adjusted model has enhanced the ability to predict urinary cadmium level， which provides a new， more accurate method for the risk assessment of food safety.

Keywords

• cadmium
• relative bioavailability
• pbtk model
• aquatic product
• markov chain-monte carlo
• shanghai population