PCDD/Fs in human tissues: A review of global biomonitoring data

This review investigates the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in internal human organs and tissues - excluding blood - with a particular focus on adipose tissue studies conducted worldwide up to January 2025. A thorough analysis of published literature highlights significant geographical and temporal trends in human PCDD/F exposure, including potential associations between PCDD/F levels and various health conditions. Several research gaps are identified, and proposals for future studies are given. Studies from Europe, Asia, and North America demonstrated a general decline in tissue PCDD/F concentrations over recent decades, particularly from the 1970s to early 2000s, attributed to successful emission control measures. Adipose tissue PCDD/F levels were typically higher in industrialized regions, with occupational exposure studies showing significantly elevated concentrations compared to the general population. Notable regional variations were observed, with some Asian countries continuing to show relatively high PCDD/F levels despite the overall declining trend. The review also highlighted potential associations between PCDD/F exposure and various health conditions, including endometriosis and cryptorchidism, though causal relationships remain unclear. Physiologically Based Pharmacokinetic (PBPK) modeling studies estimate valuable insights into the distribution and accumulation of these compounds in human tissues. Research gaps identified include limited data from developing countries and other underrepresented regions. It is also important to acknowledge the variability in analytical methods and reporting units across the reviewed studies, which may complicate direct comparisons of results. This review emphasizes the importance of continued biomonitoring efforts, particularly in underrepresented regions, to track exposure trends and protect vulnerable populations.