Multiple Environmental Sources of Exposure to Polychlorinated Biphenyls (PCBs): Relative Contributions and Health Risks—A Global Systematic Review and Scientometric Analysis

Introduction: This systematic review aimed to identify studies that simultaneously examined more than one source of exposure to polychlorinated biphenyls (PCBs) and evaluated the contribution of each source and associated health risks. Methods: This study was conducted in compliance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A comprehensive literature search was performed in the Scopus, Web of Science, and PubMed databases using predefined key terms up to March 21, 2024. Two reviewers independently assessed titles, abstracts, keywords, and full texts, and resolved disagreements by consulting a third reviewer. We assessed the methodological quality of the included studies using the modified Newcastle-Ottawa Scale (NOS). The CiteSpace. 6.3.R1 software was used to visualize co-citation and keyword co-occurrence networks related to our research topic. Results: A total of 2,123 records were initially identified, and after screening and eligibility assessment, 11 eligible articles met the inclusion criteria. Of these, all studies examined sources of exposure through food and air, whereas sources of exposure through drinking water and soil were evaluated less frequently. The numbers and types of PCB congeners varied substantially across studies, ranging from 6 to 205. Dietary intake was the most frequently reported contributor to PCB exposure. Only four studies conducted quantitative health risk assessments, reporting variable carcinogenic and non-carcinogenic risks depending on exposure source and population characteristics. Visualizing the software results revealed that dietary intake, persistent organic pollutants, dioxin-like PCBs, and risk assessment are the active and emerging research themes in this field. Conclusion: Overall, available evidence suggests that dietary exposure remains the major contributor to PCB intake in the general population; however, evidence on the simultaneous contributions of multiple exposure pathways and their associated health risks remains limited world wide. Future large-scale, standardized studies are needed to comprehensively evaluate all major PCB exposure routes and improve global health risk assessment frameworks.