Study on the regulatory effect of biochar-based materials on the migration and accumulation of perfluoroalkyl substances in paddy soil-water-plant systems

Accumulation of perfluoroalkyl substances in human tissues

Concerning the involvement of living matter into the global matter and energy flows in the biosphere, migration of substances along trophic chains in natural ecosystems is a factor of greatest functional significance. As the internal structure of ecosystems is based on stable trophic connections through the matter and energy flows, the pattern of migration and accumulation of substances in the trophic links of ecosystems may serve as an indicator of ecosystem stability (Krivolutskii and Pokarzhevskii, 1990). In other words, the constancy of the rate of matter and energy flow and accumulation in the trophic chains of an ecosystem characterizes its state as stable. This primarily concerns the ecosystems of background areas. In this context, it appears important to perform comparative studies on the migration and accumulation of substances in the trophic chains of natural ecosystems unaffected by the anthropogenic impact. The main purpose is to reveal both the general pattern of these processes on the biospheric scale and specific regional or local features of the input and accumulation of certain substances and elements in the trophic links of individual ecosystems.

Perfluoroalkyl substances (PFAS) are ubiquitous and persistent environmental contaminants, yet knowledge of their biological effects and mechanisms of action is limited. The highest aqueous PFAS concentrations are found in areas where bacteria are relied upon for functions such as nutrient cycling and contaminant degradation, including fire-training areas, wastewater treatment plants, and landfill leachates. This research sought to elucidate one of the mechanisms of action of PFAS by studying their uptake by bacteria and partitioning into model phospholipid bilayer membranes. PFAS partitioned into bacteria as well as model membranes (phospholipid liposomes and bilayers). The extent of incorporation into model membranes and bacteria was positively correlated to the number of fluorinated carbons. Furthermore, incorporation was greater for perfluorinated sulfonates than for perfluorinated carboxylates. Changes in zeta potential were observed in liposomes but not bacteria, consistent with PFAS being incorporated into the phospholipid bilayer membrane. Complementary to these results, PFAS were also found to alter the gel-to-fluid phase transition temperature of phospholipid bilayers, demonstrating that PFAS affected lateral phospholipid interactions. This investigation compliments other studies showing that sulfonated PFAS and PFAS with more than seven fluorinated carbons have a higher potential to accumulate within biota than carboxylated and shorter-chain PFAS.

Accumulation of perfluoroalkyl substances in lysimeter-grown rice in Japan using tap water and simulated contaminated water

Despite the known persistence and bioaccumulation potential of perfluoroalkyl substances (PFAS), much uncertainty exists regarding their bioavailability in the terrestrial environment. Therefore, this study investigated the influence of soil characteristics and PFAS concentrations on the adsorption of PFAS to soil and their influence on the PFAS bioavailability to terrestrial plants and invertebrates. PFAS concentrations and profile were compared among different invertebrate and plant species and differences between leaves and fruits/nuts of the plant species were assessed. Soil concentrations were primarily affected by organic carbon content. The PFAS accumulation in biota was, except for PFOA concentrations in nettles, unrelated to the soil concentrations, as well as to the soil characteristics. The PFAS profiles in soil and invertebrates were mainly dominated by PFOA and PFOS, whereas short-chained PFAS were more abundant in plant tissues. Our results show that different invertebrate taxa accumulate different PFAS, likely due to dietary differences. Both long-chained and, to lesser extent, short-chained PFAS were observed in herbivorous invertebrate taxa, whereas the carnivorous invertebrates only accumulated long-chained PFAS. Correlations were observed between PFOA concentrations in herbivorous invertebrates and in the leaves of some plant species, whereas such relationships were absent for the carnivorous spiders. It is essential to continuously monitor PFAS exposure in terrestrial organisms, taking into account differences in bioaccumulation, and subsequent potential toxicity, among taxa, in order to protect the terrestrial ecosystem.

We synthesize current understanding of the magnitudes and methods for assessing human and wildlife exposures to poly- and perfluoroalkyl substances (PFAS). Most human exposure assessments have focused on 2 to 5 legacy PFAS, and wildlife assessments are typically limited to targeted PFAS (up to ~30 substances). However, shifts in chemical production are occurring rapidly, and targeted methods for detecting PFAS have not kept pace with these changes. Total fluorine measurements complemented by suspect screening using high-resolution mass spectrometry are thus emerging as essential tools for PFAS exposure assessment. Such methods enable researchers to better understand contributions from precursor compounds that degrade into terminal perfluoroalkyl acids. Available data suggest that diet is the major human exposure pathway for some PFAS, but there is large variability across populations and PFAS compounds. Additional data on total fluorine in exposure media and the fraction of unidentified organofluorine are needed. Drinking water has been established as the major exposure source in contaminated communities. As water supplies are remediated, for the general population, exposures from dust, personal care products, indoor environments, and other sources may be more important. A major challenge for exposure assessments is the lack of statistically representative population surveys. For wildlife, bioaccumulation processes differ substantially between PFAS and neutral lipophilic organic compounds, prompting a reevaluation of traditional bioaccumulation metrics. There is evidence that both phospholipids and proteins are important for the tissue partitioning and accumulation of PFAS. New mechanistic models for PFAS bioaccumulation are being developed that will assist in wildlife risk evaluations. Environ Toxicol Chem 2021;40:631-657. © 2020 SETAC.

Poly- and perfluoroalkyl substances (PFAS) are environmentally persistent contaminants that pose growing food safety concerns due to their potential for accumulation in edible crops. This study investigated the uptake, translocation, and tissue distribution of 11 PFAS compounds in two hydroponically grown lettuce (Lactuca sativa L.) cultivars, Agila and Bonaly. Additionally, PFAS accumulation in Agila was assessed under field conditions in a PFAS-contaminated area. Under hydroponic conditions, lettuce plants at two developmental stages (28 and 56 days after sowing) were exposed to a mixture of PFAS at concentrations of 10 and 20 µg L−1 each. Under such conditions, Agila cultivar accumulated considerably higher levels of long-chain PFAS in both root and leaf tissues over time, whereas Bonaly cultivar demonstrated a more pronounced initial uptake and translocation of short-chain PFAS to leaves. Differently, Agila variety cultivated in a PFAS-polluted environment accumulated low concentrations of PFAS in leaf tissues, with only PFBA detected at minimal levels. The results emphasize the combined influence of plant variety, developmental stage, and cultivation methods on PFAS bioaccumulation, offering valuable guidance for food safety risk assessment and for developing targeted agricultural strategies in PFAS-contaminated areas.

Enrichment of poly- and perfluoroalkyl substances (PFAS) in the surface microlayer and foam in synthetic and natural waters

Fate of perfluoroalkyl substances within a small stream food web affected by sewage effluent

Here we review present understanding of sources and trends in human exposure to poly- and perfluoroalkyl substances (PFASs) and epidemiologic evidence for impacts on cancer, immune function, metabolic outcomes, and neurodevelopment. More than 4000 PFASs have been manufactured by humans and hundreds have been detected in environmental samples. Direct exposures due to use in products can be quickly phased out by shifts in chemical production but exposures driven by PFAS accumulation in the ocean and marine food chains and contamination of groundwater persist over long timescales. Serum concentrations of legacy PFASs in humans are declining globally but total exposures to newer PFASs and precursor compounds have not been well characterized. Human exposures to legacy PFASs from seafood and drinking water are stable or increasing in many regions, suggesting observed declines reflect phase-outs in legacy PFAS use in consumer products. Many regions globally are continuing to discover PFAS contaminated sites from aqueous film forming foam (AFFF) use, particularly next to airports and military bases. Exposures from food packaging and indoor environments are uncertain due to a rapidly changing chemical landscape where legacy PFASs have been replaced by diverse precursors and custom molecules that are difficult to detect. Multiple studies find significant associations between PFAS exposure and adverse immune outcomes in children. Dyslipidemia is the strongest metabolic outcome associated with PFAS exposure. Evidence for cancer is limited to manufacturing locations with extremely high exposures and insufficient data are available to characterize impacts of PFAS exposures on neurodevelopment. Preliminary evidence suggests significant health effects associated with exposures to emerging PFASs. Lessons learned from legacy PFASs indicate that limited data should not be used as a justification to delay risk mitigation actions for replacement PFASs.

Levels and oxidative toxicity of microplastics and perfluoroalkyl substances (PFASs) in different tissues of sea cucumber (Holothuria tubulosa).

The developed series of soil-geochemical maps reveals the ecological functions of soils and the soil cover associated with the processes of migration, transformation, and accumulation of chemicals substances in landscapes. The thematic basis for the maps was the electronic version of the soil map of the Russian Federation with a scale of 1 : 2 500 000 and the Unified State Register of Soil Resources of the Russian Federation developed on its basis, as well as regional sources and the database of soil properties of the Perm Territory. Prepared maps represented by two main blocks — basic and applied, each of which, in turn, includes constituent and assessment maps. The article discusses the methodological foundations, the compilation methodology and the content of the presented maps. Baseline maps reveal the most common soil-geochemical patterns of migration and accumulation of substances in soils. The block includes: maps of the thicknesses of organogenic and humus soil horizons, cation exchange capacities, and sorption capacity of soils. These maps make it possible to characterize the sorption properties of surface soil horizons as the most important geochemical barriers for technogenic substances. An analysis of the content of these maps allows us to conclude that the sorption capacity of the most common soils in the region is estimated to be very low and low, due to the low thickness of the humus horizons and low cation exchange capacity of podzolic soils. Podzolized chernozems, soddy-gley and soddy-carbonate soils have an increased sorption ability, but their distribution area is small. The high sorption capacity of soils is associated with a significant thickness of organogenic horizons in hydromorphic soils. The application block is devoted to the analysis of soil properties in relation to heavy metals as a priority group of pollutants for which the soil is a depositing medium. Two maps are included in this block — “Conditions for the migration of heavy metals in soils” and “Sensitivity of soils”. The conditions for the migration of heavy metals highlighted on the map of the same name are represented by 12 options. In the northern and central parts of the region, conditions prevail that combine constant or seasonal recovery conditions and low pH values. In the southern part of the region they are replaced by oxidative weakly acidic. The assessment of the sensitivity of soils to heavy metal pollution is given on the basis of expert assessment. The soils of the region are defined as sensitive and very sensitive, that is, they relatively quickly change their properties to a negative side under the influence of anthropogenic load.

Environmental and health impacts of PFAS: Sources, distribution and sustainable management in North Carolina (USA)

Bioaccumulation of perfluoroalkyl substances in marine echinoderms: Results of laboratory-scale experiments with Holothuria tubulosa Gmelin, 1791

Bone marrow accumulation of perfluoroalkyl substances (PFASs) predicts post-transplant relapse in acute myeloid leukemia patients and associated with T-cell dysregulation.