Co-Occurrence, Bioaccumulation, and Dietary Risk Assessment of Per- and Polyfluoroalkyl Substances and Heavy Metals...

Area of Science:

• Environmental Chemistry
• Food Safety
• Toxicology

Background:

• Co-occurrence of PFASs and HMs in rice poses poorly understood dietary health risks.
• Rice is a staple food, making its contamination with PFASs and HMs a significant public health concern.
• Limited data exists on the combined bioaccumulation and translocation of these contaminants in rice tissues.

Purpose of the Study:

• To analyze the co-occurrence and combined dietary health risks of PFASs and HMs in rice.
• To determine the bioaccumulation and translocation patterns of specific PFASs and HMs in rice plants.
• To assess the dietary exposure and associated health risks for different age groups consuming contaminated rice.

Main Methods:

• Analysis of 29 PFAS compounds and 4 HMs in rice tissues (grain, leaves, straw, roots) from paddy fields.
• Quantification of contaminant concentrations using advanced analytical techniques.
• Calculation of bioaccumulation and translocation factors for PFASs and HMs.
• Dietary risk assessment using hazard index (HI) calculations for various age demographics.

Main Results:

• HFPO-DA was dominant in brown rice; PFOA accumulated in leaves/straw. Elevated Cd and Cu concentrations were found in grains.
• PFASs showed higher bioaccumulation and translocation factors than HMs, particularly in aboveground tissues.
• Dual root and foliar uptake pathways were suggested for HFPO-DA and Cd.
• Dietary assessment indicated HFPO-DA, PFOS, Cd, and Cu in brown rice exceeded safety thresholds for multiple age groups.
• The cumulative HI for toddlers consuming brown rice was significantly elevated (10.7), posing substantial health risks.

Conclusions:

• Combined exposure to PFASs and HMs in rice presents significant dietary health risks, particularly for vulnerable populations like toddlers.
• Rice contamination with these compounds necessitates enhanced food safety monitoring and risk management strategies.
• Understanding uptake pathways is crucial for mitigating contaminant accumulation in edible rice portions.