Novel risk assessment strategy of co-exposure of arsenic and cadmium in seaweeds based on in vivo-in vitro correlation, bio-transformation and speciation

In recent years, global consumption of seaweed has been on the rise, yet there is a lack of accurate methods for assessing the health risks associated with its consumption. This gap could pose a threat to public safety or lead to wasted resources by government regulatory bodies. In this study, animal models and an innovative PBET (IPBET) were used to determine the bioavailability and bioaccessibility of arsenic (As) and cadmium (Cd) in various seaweeds, followed by an in vivo-in vitro correlation (IVIVC) analysis. The results indicated that the bioaccessibility of As and Cd was strongly correlated with As-RBA and Cd-RBA, highlighting the method's significant potential for predicting As-RBA and Cd-RBA in seaweeds. Additionally, the study explored the impact of mineral elements on the bioaccessibility of As and Cd in seaweed, finding a significant influence. In vivo metabolism experiments in mice revealed that different As species undergo several biochemical transformations in the body, including oxidation, reduction, methylation, and demethylation, all of which should not be overlooked. Building on previous studies, we have developed a new perspective for risk assessment of combined As and Cd exposure in seaweed. Calculations of the target hazard quotient (THQ) and total risk (TR) indicated that factoring in the bioavailability of heavy metals, As species, and biotransformation rates (BR) substantially reduces the health risks associated with seaweed consumption. However, for populations consuming seaweed over the long term, there still remains a certain level of risk to human health.