Human biomonitoring and environmental health: a critical review of global exposure patterns, methodological challenges and research gaps.

Abstract

Human biomonitoring (HBM) is an essential approach for assessing exposure to environmental toxicants and for informing risk assessment frameworks. However, the global expansion of HBM has (1) outpaced efforts to harmonize methodologies, (2) addressed contextual inequalities, and (3) translated findings into public health interventions. This review examined literature regarding HBM across different contaminant categories including atmospheric pollutants, heavy metals, mycotoxins, persistent organic pollutants (POPs) and per- and polyfluoroalkyl substances (PFAS). Drawing on recent studies, key trends, methodological inconsistencies, and systemic biases in research design and population coverage were identified. This review noted an overrepresentation of studies in high-income countries, limited data from vulnerable populations, and a persistent reliance on cross-sectional designs. There is significant heterogeneity in biomarker selection, analytical protocols, and interpretation of exposure-health relationships. Further, many investigations failed to control for confounding variables or explore toxicokinetic and toxicodynamic mechanisms, limiting causal inference. Further, exposure to complex chemical mixtures was routinely underexplored, despite evidence of potential interactive effects. The review presents critical gaps in current knowledge, particularly regarding long-term health effects and translation of biomonitoring data into risk management policies. This review emphasizes the need for standardized methodologies, expanded research in low- and middle-income settings, and integration of biomonitoring with community-based surveillance and environmental justice frameworks. Future research needs to prioritize longitudinal designs, interdisciplinary approaches, and greater inclusion of socially and geographically marginalized groups. By reconceptualizing HBM as both a scientific and socio-political endeavor, the field might more effectively contribute to global environmental health protection.