Bioavailability of potentially toxic metals and human health risk assessment: Bibliometric analysis and systematic review

The assumption of hundred percent bioavailability and total concentration of potentially toxic metals for ingestion exposure assessment and risk characterization leads to overestimation and uncertainty in risk characterization. Previous studies have conducted in vivo animal experiments, which are expensive, have ethical challenges, and consume time. Therefore, in vitro risk estimation approaches measuring bioaccessibility have been used in modern studies. This study provided a bibliometric analysis and systematic review of the literature on bioaccessibility and bioavailability of potentially toxic metals in soils. The review sought to respond to the following questions: (1) What acceptable and related constructs of bioavailability exist in reviewed studies? (2) What settings, sample size, and sample preparation approaches did previous studies use? (3) What methods for bioaccessibility (in vitro) and bioavailability (in vivo) existed in the literature, their performances, and limitations? (4) Did previous studies provide quality assurance and control procedures? (5) What metals have previous studies considered concerning bioaccessibility and bioavailability, and their common assessment methods? (6) What factors influence the bioaccessibility and bioavailability of metals in contaminated soils? Reviews integrating bibliometric analysis and systematic reviews on bioaccessibility and bioavailability of metals, as well as health risk assessment, are scant and not current; therefore, this study added current perspectives. This study identified knowledge gaps for future research in the field. It will aid in developing novel and hybrid methods to reduce the uncertainties in exposure estimations and health risk characterization.