Phytoremediation evaluation of forever chemicals using hemp (Cannabis sativa L.): Pollen bioaccumulation and the risk to bees

Per- and polyfluoroalkyl substances (PFAS), often termed "forever chemicals," are a diverse group of persistent fluorinated compounds, including the well-known perfluorooctanesulfonic acid (PFOS), which has been identified as lethal to bee larvae. However, the risk of PFAS exposure through pollen, a bee's primary food source, has not been thoroughly investigated. In controlled greenhouse experiments, Cannabis sativa L. (hemp) plants were cultivated in soil contaminated with eight PFAS compounds. Phytoremediation potential was assessed by measuring bioconcentration factors (BCF) in both the total above-ground biomass and pollen. The study found that BCF for total PFAS in hemp pollen was significant (>20.8), with over 45% of the total PFAS uptake of around 3248 μg/kg concentrated in the pollen. Based on these figures, the estimated daily intake (EDI) of PFOS for western honeybees (Apis mellifera) was found to be about 124.5 μg/kg body weight per day. These findings underscore a critical global threat to pollinator health, with significant implications for agriculture and biodiversity.