Per- and Polyfluoroalkyl-Contaminated Freshwater Impacts Adjacent Riparian Food Webs

Abstract

The occurrence of per-and polyfluoroalkyl substances (PFASs) in aquatic ecosystems is a global concern because of their persistence, potential bioaccumulation, and toxicity. In this study, we investigated a PFAS-contaminated pond in Sweden to assess the cross-boundary transfer of PFASs from the aquatic environment to the riparian zone via emergent aquatic insects. Aquatic and terrestrial invertebrates, surface water, sediments, soils, and plants were analyzed for 24 PFASs including branched isomers. Stable isotope analysis of carbon and nitrogen was performed to elucidate the importance of diet and trophic position for PFAS uptake. We present the first evidence that PFASs can propagate to the riparian food web via aquatic emergent insects. Elevated Σ 24 PFAS concentrations were found in aquatic insect larvae, such as dragon-and damselflies, ranging from 1100 to 4600 ng g −1 dry weight (dw), and remained high in emerged adults (120−3500 ng g −1 dw), indicating exposure risks for top predators that prey in riparian zones. In terrestrial invertebrate consumers, PFAS concentrations increased with the degree of aquatic-based diet and at higher trophic levels. Furthermore, stable isotope data together with calculated bioaccumulation factors indicated that bioconcentration of PFASs was the major pathway of exposure in the aquatic food web and bioaccumulation in the riparian food web.

Quantification of Biodriven Transfer of Per- and Polyfluoroalkyl Substances from the Aquatic to the Terrestrial Environment via Emergent Insects

“… 33 However, the biomass of emergent aquatic insects collected in that study was not sufficient for quantification of PFAS transferred from water to land. 33 Here, we extend this concept by providing quantitative data on PFAS and explore biodriven transport based on different scenarios for three other sites of varying size, productivity, and contamination extent. To do this, we collected a comprehensive set of samples in 2017 and in 2018, in a PFAS-affected area in Sweden.…”

“… 30 − 32 In a previous study, we investigated a pond contaminated by aqueous film forming foam (AFFF), and found high concentrations of 24 PFAS in aquatic invertebrates, including emergent aquatic insects, such as adult dragonflies. 33 Hence, terrestrial consumers feeding on emergent aquatic insects from PFAS-contaminated systems could be exposed to PFAS via predation. 33 However, the biomass of emergent aquatic insects collected in that study was not sufficient for quantification of PFAS transferred from water to land.…”

“… 33 Hence, terrestrial consumers feeding on emergent aquatic insects from PFAS-contaminated systems could be exposed to PFAS via predation. 33 However, the biomass of emergent aquatic insects collected in that study was not sufficient for quantification of PFAS transferred from water to land. 33 Here, we extend this concept by providing quantitative data on PFAS and explore biodriven transport based on different scenarios for three other sites of varying size, productivity, and contamination extent.…”

Microplastics in terrestrial ecosystems: Moving beyond the state of the art to minimize the risk of ecological surprise

“…Additional studies on effects of microplastics on terrestrial food web stability, critical ecological processes (e.g., biogeochemical cycles and pollination) and interactions with other anthropogenic stressors must be conducted. Other contaminants, for example, dichlorodiphenyltrichloroethane (DDT; Colborn et al, 1993), per-and polyfluoroalkyl substances (PFAS; Koch et al, 2020) and antibiotics (Ferri et al, 2017) that share similar characteristics as microplastics (i.e., high persistency and widespread presence in the environment) have caused unexpected ecosystem responses including the near extinction of iconic predatory bird species (ospreys and bald eagles; Wiemeyer et al, 1975Wiemeyer et al, , 1984 and even put human health at risk (Fry, 1995;Sunderland et al, 2019). Unlike other chemical contaminants, microplastics have unique properties: make up of diverse polymers, broad size ranges including the nano scale (<0.1 µm), vary in shape and contain diverse chemical additives (Rochman et al, 2019), which increase their likelihood to impact ecosystems and cause ecological surprises.…”

Endocrine disruption by PFAS: A major concern associated with legacy and replacement substances

“…By virtue of their unique chemical structure, conferring exceptional thermal and chemical stability in addition to water repellence and tensioactive properties, PFAS have been used in a variety of industrial processes and consumer products including firefighting foams, textiles, anti-adherent coatings, food packaging, cosmetics and paints (4). Once released into the environment, these substances are recalcitrant to degradation processes, can migrate towards distant sites and tend to bioaccumulate into living organisms, ultimately entering into the food webs of different ecosystems (5,6). While many efforts have been made to define the toxicological effects of PFAS on susceptible human subpopulations, our knowledge is still limited to few individual substances such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), which, despite having been phased out by the major producers, are still largely present in the environmental media across the globe (1,7).…”