Per- and Poly-fluoroalkyl Substances in the Food Chain: A Review of Exposure Pathways and Long-term Health Consequences View PDF

The presence of PFAS in the food chain has emerged as a significant concern due to their persistence, bioaccumulation potential, and associated health risks [1-7]. Recent literature underscores the complexity of exposure pathways and the long-term health consequences stemming from chronic low-level exposure to these chemicals [8- 14]. A primary focus of current research is identifying and mapping the pathways through which PFAS enter the human diet. Melnyk et al. [15] conducted extensive evidence mapping and scoping review to elucidate these pathways, emphasizing the importance of dietary exposure routes. Their study highlights that PFAS contamination can occur at multiple points along the food chain, including environmental contamination of soil and water, uptake by crops, and accumulation in terrestrial and aquatic organisms that are subsequently consumed by humans. This comprehensive approach underscores the multifaceted nature of exposure, involving environmental matrices such as irrigation water and soil, which serve as reservoirs for PFAS, thereby facilitating transfer into food products.

The contamination of terrestrial food chains is particularly concerning, as demonstrated by Bonato et al. [16], who reviewed the long-term health impacts of chronic low-level PFAS exposure through diet. Their findings suggest that persistent environmental contamination leads to bioaccumulation in crops and livestock, which then becomes a direct source of human exposure. This pathway is compounded by the chemical stability of PFAS, often termed ‘forever chemicals,’ which resist degradation and persist in the environment for extended periods. The review emphasizes that such contamination not only affects food safety but also poses ongoing health risks to populations consuming contaminated products. Further elucidating the environmental aspects, the analysis by Melnyk et al. [15] and others indicates that PFAS can infiltrate various environmental compartments, impacting ecosystems and food safety simultaneously [17]. The contamination of water sources used for irrigation and drinking is a critical concern, as it facilitates the transfer of PFAS into crops and animals. The review by Brown et al. [18] highlights that irrigation water and soil contaminated with PFAS are significant exposure sources, raising regulatory concerns about the safety of agricultural practices and the need for monitoring and remediation strategies.

The health implications of dietary PFAS exposure are increasingly documented [19-25]. Studies reviewed by Fenton et al. [26] reveal associations between long-chain PFAS exposure and adverse health outcomes, including kidney cancer and mortality. Specifically, a review of 6 published studies found that exposure to long-chain PFAS compounds correlates with increased risks of kidney-related health issues, with risk ratios ranging from 1.07 to higher values, indicating a measurable increase in health risks [26]. These findings are corroborated by long-term epidemiological studies that link PFAS exposure to chronic health conditions, emphasizing the importance of understanding exposure duration and chemical persistence. Emerging research also points to the vulnerability of early life stages to PFAS exposure. The review by Eze et al. [27] discusses how prenatal and early childhood exposure to PFAS can have latent health effects, with the placenta identified as a target tissue for chemical accumulation. This suggests that exposure during critical developmental windows may predispose individuals to health issues later in life, including immune dysregulation and metabolic disturbances. Such findings highlight the importance of considering vulnerable populations in risk assessments and regulatory policies.

The ongoing phase-out of certain long-chain PFAS compounds, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), has been examined for its impact on environmental and human health [28-33]. Revisiting these chemicals, Wee and Aris [34] discusses how their reduction influences the concentrations of perfluoroalkyl acids in the environment and food products. While phase-out efforts have led to decreased levels of some PFAS in certain matrices, the persistence of these chemicals and the emergence of alternative compounds continue to pose challenges [34]. Overall, the literature underscores that PFAS contamination in the food chain is a complex issue involving multiple environmental and biological pathways. The persistence of these chemicals in soil, water, and biota facilitates ongoing exposure, which is associated with significant long-term health risks, including cancer, immune dysfunction, and developmental effects. The evidence mapping by Melnyk et al. [15] provides a foundational understanding of these pathways, emphasizing the need for integrated monitoring, risk assessment, and regulatory strategies to mitigate exposure and protect public health.

In summary, the current body of research highlights the critical importance of understanding and addressing the pathways through which PFAS enter the food chain. The long-term health consequences of such exposure are profound, necessitating continued investigation into environmental contamination, bioaccumulation, and health outcomes. As efforts to phase out certain PFAS compounds progress, ongoing vigilance is essential to manage emerging risks associated with persistent and bioaccumulative chemicals in the environment and food supply.