Assessing Human Health Risks from Per- and Polyfluoroalkyl Substance (PFAS)-Impacted Vegetable Consumption: A Tiered Modeling Approach

Abstract

Irrigation water or soil contaminated with per-and polyfluoroalkyl substances (PFASs) raises concerns among regulators tasked with protecting human health from potential PFAScontaminated food crops, with several studies identifying crop uptake as an important exposure pathway. We estimated daily dietary exposure intake of individual PFASs in vegetables for children and adults using Monte Carlo simulation in a tiered stochastic modeling approach: exposures were the highest for young children (1−2 years > adults > 3−5 years > 6−11 years > 12−19 years). Using the lowest available human health toxicity reference values (RfDs) and no additional exposure, estimated fifth percentile risk-based threshold concentrations in irrigation water were 38 ng/L (median 180 ng/L) for perfluorooctanoate (PFOA) and 140 ng/L (median 850 ng/L) for perfluorooctane sulfonate (PFOS). Thus, consumption of vegetables irrigated with PFAS-impacted water that meets the current 70 ng/L of PFOA and PFOS U.S. Environmental Protection Agency's lifetime health advisory for drinking water may or may not be protective of vegetable exposures to these contaminants. Hazard analyses using real-world PFAScontaminated groundwater data for a hypothetical farm showed estimated exposures to most PFASs exceeding available or derived RfDs, indicating water-to-crop transfer is an important exposure pathway for communities with PFAS-impacted irrigation water.

Uptake of perfluorinated alkyl acids by crops: results from a field study

“…12 They recently revised these TDIs and established a new and much lower tolerable weekly intake rate of 4.4 ng per kg bw per week for the extended group of PFOA, PFNA, PFHxS and PFOS. 13 Food has been identied as the main source of human exposure, [14][15][16][17][18][19] and crops are one possible vector for PFAAs into the food supply. PFAAs are taken up by crops when grown in soil that has been contaminated, for instance via water reuse irrigation or biosolids application, 20,21 and there are two known cases where agricultural sites have been widely contaminated with PFAAs in Germany.…”

Longitudinal assessment of point‐of‐use carbon filters for removal of per‐ and polyfluoroalkyl substances from private well water

“…At this drinking water: serum ratio, even the low influent PFOA and PFOS concentrations in this study (Table 2) could result in blood serum levels up to 20 times higher than the serum-based reference dose of 0.1 ng/mL proposed by Grandjean and Budtz-Jørgensen (2013) based on reduced vaccine response in children. As research regarding an appropriate reference dose continues for many PFAS (Brown et al, 2020;, these data suggest that implementation of ACB filters could help reduce immunotoxic and other health effects associated with chronic, low-level exposures to PFAS from private well water.…”

The Phytomanagement of PFAS-Contaminated Land

“…respectively [ 94 ]. This value may be exceeded if crops are irrigated with water that meets the current USEPA’s health advisory guideline of 70 ng L −1 [ 95 ]. Plant uptake experiments in greenhouse and field conditions ( Table 3 and Table 4 , respectively) indicate that when grown in PFAS-contaminated soil, plant uptake of PFOS and PFOA can exceed >1000 µg kg −1 .…”