PFAS use in electronic products and exposure risks during handling and processing of e-waste: A review

Leaching profile of per- and polyfluoroalkyl substances (PFAS) from biosolids after thickening, anaerobic digestion, and dewatering processes, and significance of protein, phosphorus, and selected ions

Batch leaching experiments were conducted to evaluate the release of forty per- and polyfluoroalkyl substances (PFAS) from sludge samples collected after thickening, anaerobic digestion, and dewatering processes at two wastewater treatment plants. The South District wastewater treatment plant (SDWWTP), which receives domestic wastewater and landfill leachate from a nearby landfill, and the Central District wastewater treatment plant (CDWWTP), which receives only domestic wastewater, were selected for this study. PFAS released into the aqueous phase were analyzed by sacrificial sampling after 1, 3, 7, 14, and 30 days. Results demonstrated rapid PFAS leaching, with the highest levels detected in biosolid leachates after just one day. Distinct differences were observed in PFAS composition and concentrations between the two treatment plants. Of the forty PFAS measured, nineteen were detected, with higher concentrations identified at SDWWTP. The input of landfill leachate to SDWWTP appears to have significantly contributed to the elevated levels of specific PFAS, particularly long-chain compounds, compared to the emerging short-chain PFAS found in biosolids. In addition to PFAS analysis, the compositions of the sludge samples, including total and volatile solids, protein, phosphorus (P), iron, aluminum, calcium, and magnesium, were also assessed. Spearman correlation analyses revealed moderate to strong relationships between PFAS levels in leachate and certain sludge components. For instance, correlations between P content and PFCAs and FTCAs were moderate (R2 = 0.45-0.76). In thickener sludge leachate, strong correlations were observed for FPrPA (3:3 FTCA), PFDA, and PFTrDA with P, with R2 values of 0.60, 0.53, and 0.54, respectively. In the digested sludge, correlations were found for PFHpA, PFDA, and PFNA (R2 = 0.45-0.76). Also, for digested sludge leachate, strong correlations were found between the individual compounds PFHpA, PFHxA, PFNA, PFOA, and PFPeA (R2 = 0.60-0.88). Predominant PFAS in leachate from biosolids were identified, including PFOS, FPePA (5:3 FTCA), PFPeA, PFBA, PFHxA, N-EtFOSAA, and 6-2 FTS.

Increased health risk from co-exposure to polycyclic aromatic hydrocarbons, phthalates, and per- and polyfluoroalkyl substances: Epidemiological insight from e-waste workers in Hong Kong

The alarming surge in electronic waste (e-waste) in Hong Kong has heightened concerns regarding occupational exposure to a myriad of pollutants. Among these, polycyclic aromatic hydrocarbons (PAHs), phthalates (PAEs), and per- and polyfluoroalkyl substances (PFASs) are prevalent and known for their harmful effects, including the induction of oxidative stress and DNA damage, thereby contributing to various diseases. This study addresses gaps in knowledge by investigating exposure levels of these pollutants-measured via hydroxylated PAHs (OH-PAHs), phthalate metabolites (mPAEs), and PFASs-in urine from 101 e-waste workers and 100 office workers. E-waste workers exhibited higher concentrations of these substances compared to office workers. Elevated urinary levels of OH-PAHs, mPAEs, and PFASs correlated significantly with increased 8-hydroxy-2-deoxyguanosine (8-OHdG) levels (β = 2.53, 95 % CI: 2.12-3.02). The association between short-chain PFASs (Perfluoropentanoic acid, PFPeA) and DNA damage was discovered for the first time. Despite most participants (95 %) showing hazard index (HI) values below non-carcinogenic risk thresholds for PAHs and PAEs, certain pollutants posed higher risks among e-waste workers, necessitating enhanced protective measures. Moreover, the 95th percentile of carcinogenic risk associated with diethylhexyl phthalate (DEHP) exceeded 10-4 in both groups, highlighting the urgent need for regulatory measures to mitigate DEHP exposure risks in Hong Kong.

Atmospheric concentrations of per- and polyfluoroalkyl substances and their emissions at a waste recycling facility producing refuse-derived paper and plastics densified fuel

To better understand the types and concentrations of per- and polyfluoroalkyl substances (PFAS) emitted into the air from waste recycling facilities that produce refuse-derived paper and plastics densified fuel (RPF) from industrial waste, we conducted an air sampling campaign at a waste recycling facility in Japan. Both passive and active air sampling were conducted, and the samples collected were used to quantify the PFAS emitted into the air during the production of RPF. Overall, few ionic PFAS were detected in the air at the facility; however, high levels of neutral PFAS (8.21-53.4 ng/m3; 20.7-130 pmol/m3) were measured in the air near the heat molding machines. The two neutral PFAS detected at the highest concentrations were 6:2 fluorotelomer alcohol and 6:2 fluorotelomer methacrylate, which are currently unregulated under the Stockholm Convention, suggesting that product manufacturers have shifted away from using regulated PFAS. Small amounts of regulated PFAS such as 8:2 fluorotelomer methacrylate and 8:2 fluorotelomer acrylate were measured in some parts of the facility. Analysis of the concentrations of PFAS in the exhaust gas from the heat molding machines revealed neutral PFAS concentrations (537-2160 ng/m3; 1350-5040 pmol/m3) that were 1-2 orders of magnitude higher than those in the surrounding indoor air. The total emission of neutral PFAS from the facility to the environment was estimated to be 0.066-0.260 g/day (0.168-0.607 mmol/day), depending on whether air volume discharged as exhaust gas or as indoor ventilation was considered. A contribution analysis of the emissions revealed that treating the exhaust gas from the heat molding machines, which constitutes over 94 % of the total emissions, is very effective at reducing PFAS emissions from the facility.

Contamination levels of per- and polyfluoroalkyl substances (PFAS) in recent North American precipitation events. A review

Per- and polyfluoroalkyl substances (PFAS), known as forever chemicals, have received international attention over the last two decades for their health risks and environmental persistence. One pathway of human exposure to PFAS is by rainwater. This review aims to analyze current studies of legacy and emerging PFAS contamination levels in rainwater in North America. In April 2024, the US Environmental Protection Agency (EPA) finalized new regulations for PFAS levels in drinking water. This review compares PFAS in rainwater to the latest US EPA regulation for the first time. Our analysis determined that five recent studies' average total PFAS (ΣPFAS) ranged from 2.28 to 92.42 ng/L and had a hazard index (HI) of 0.05-0.30. The average ΣPFAS and HI for all five studies are below the maximum contamination levels (MCLs) recommended by the EPA. However, rainwater samples collected near local point sources often exceeded the MCLs. To better understand the extent of PFAS contamination in the United States, more studies need to be conducted and analyzed throughout North America, testing for both legacy and emerging PFAS and locating local point sources.

PFAS in biosolids: Accumulation characteristics and fate profiles after land application

The land application of biosolids as a management practice is considered a beneficial use for improving crop yield and reducing the need for other fertilizers. PFAS enter wastewater treatment plants through collection networks, including industrial discharges, the use of PFAS-containing products, and runoff. Therefore, PFAS may be present in biosolids derived from sewage sludge. The objectives of this study were to evaluate PFAS levels in biosolids samples collected at two wastewater treatment plants operated by the Miami Dade Water and Sewer Department (MDWASD): (1) the South District Wastewater Treatment Plant (SDWWTP) which received landfill leachate and (2) the Central District Wastewater Treatment Plant (CDWWTP). Sludge samples were collected after thickening, anaerobic digestion, and dewatering processes. The samples were subjected to batch leaching tests for 30 days. After the leaching tests, the PFAS levels in the liquid and solid fractions were analyzed for 40 PFAS. The findings show that during the aeration process (i.e., activated sludge process), PFAS are removed from the wastewater and accumulate on the solids. When the thickened sludge is digested, some PFAS are released to the liquid phase as the volatile solids decompose. During the dewatering process by centrifugation, PFAS that are partitioned to the liquid phase are removed, reducing PFAS content in the dewatered biosolids. Of the 40 PFAS analyzed, 24 were detected in leachate or solid residue samples. Samples from the SDWWTP had higher levels of PFAS due to the contribution from landfill leachate discharged to this facility. The partitioning of PFAS between the liquid phase and solid residue after 30 days of mixing indicates that the majority of PFAS in the biosolids are highly soluble and have a high tendency to be mobilized (by runoff, irrigation, precipitation) after land application. The fate profiles of PFAS biosolids were evaluated in terms of their solubility and retardation characteristics.

Association Between Prenatal Exposure to Per- and Poly-Fluoroalkyl Substances From Electronic Waste Disassembly Areas and Steroid Hormones in Human Milk Samples

Per- and poly-fluoroalkyl substances (PFAS), which are long-lasting environmental contaminants that are released into the environment during the e-waste disassembly process, pose a threat to human health. Human milk is a complex and dynamic mixture of endogenous and exogenous substances, including steroid hormones and PFAS. Therefore, in this study, we aimed to investigate the association between PFAS and steroid hormones in human milk from women living close to an e-waste disassembly area. In 2021, we collected milk samples from 150 mothers within 4 weeks of delivery and analyzed them via liquid chromatography-tandem mass spectrometry to determine the levels of 21 perfluorinated compounds and five steroid hormones (estrone, estriol, testosterone, progesterone, and androstenedione [A-dione]). We also performed multiple linear regression analysis to clarify the association between maternal PFAS exposure and steroid hormone concentrations. Our results indicated that PFOA and PFOS were positively associated with estrone (β, 0.23; 95% CI, 0.08-0.39) and A-dione (β, 0.186; 95% CI, 0.016-0.357) concentrations in human milk, respectively. Further, the average estimated daily intake of PFOA and PFOS were 36.5 ng/kg bw/day (range, 0.52-291.7 ng/kg bw/day) and 5.21 ng/kg bw/day (range, 0.26-32.3 ng/kg bw/day), respectively. Of concern, the PFAS intake of breastfeeding infants in the study area was higher than the recommended threshold. These findings suggested that prenatal exposure to PFAS from the e-waste disassembly process can influence steroid hormones levels in human milk. Increased efforts to mitigate mother and infant exposure to environmental pollutants are also required.

Per- and polyfluoroalkyl substances in Chinese commercially available red swamp crayfish (Procambarus clarkii): Implications for human exposure and health risk assessment

The extensive utilization of per- and polyfluoroalkyl substances (PFASs) has led to their pervasive presence in the environment, resulting in contamination of aquatic products. Prolonged exposure to PFASs has been linked to direct hepatic and renal damage, along with the induction of oxidative stress, contributing to a spectrum of chronic ailments. Despite the recent surge in popularity of red swamp crayfish as a culinary delicacy in China, studies addressing PFASs' exposure and associated health risks from their consumption remain scarce. To address this gap, our study investigated the PFASs' content in 85 paired edible tissue samples sourced from the five primary red swamp crayfish breeding provinces in China. The health risks associated with dietary exposure were also assessed. Our findings revealed widespread detection of PFASs in crayfish samples, with short-chain perfluoroalkyl carboxylic acids (PFCAs) exhibiting the highest concentrations. Notably, the total PFAS concentration in the hepatopancreas (median: 160 ng/g) significantly exceeded that in muscle tissue (5.95 ng/g), as did the concentration of every single substance. The hazard quotient of perfluorohexanesulfonic acid (PFHxS) via consuming crayfish during peak season exceeded 1. In this case, a potential total non-cancer health risk of PFASs, which is mainly from the hepatopancreas and associated with PFHxS, is also observed (hazard index>1). Thus, it is recommended to avoid consuming the hepatopancreas of red swamp crayfish. Greater attention should be paid to governance technology innovation and regulatory measure strengthening for short-chain PFASs.

Influence of Canadian provincial stewardship model attributes on the cost effectiveness of e-waste management

This paper presents a comprehensive analysis of e-waste collection and management trends across six Canadian provinces, focusing on e-waste collection rates, provincial stewardship model attributes, program strategies and budget allocations from 2013 to 2020. Temporal and regression analyses were conducted using data from Electronic Product Recycling Association reports. A group characterization based on geographical proximity is proposed, aiming to explore the potential outcomes of fostering collaboration among neighboring provinces. The analysis emphasizes the significant impact of stewardship model attributes on e-waste collection rates, with Quebec emerging as a standout case, showcasing a remarkable 61.5% surge in collection rates. Findings from group analysis reveal a positive correlation between per capita e-waste collection rate and the growth of businesses and collection sites in Western Canada (Group A - British Columbia, Saskatchewan, and Manitoba). This highlights the potential benefits of a coordinated waste management approach, emphasizing the importance of shared resources and collaborative policies. Saskatchewan and Manitoba allocated only 6.6% and 7.0% of their respective budgets to e-waste transfer and storage. British Columbia's observed steady decrease of e-waste collection rate. In Group A, stewards handled 2.18-13.95 tonnes of e-waste during the study period. The cost per tonne of e-waste tended to be lower when more e-waste is managed per steward, suggesting the potential benefits of an integrated e-waste collection and management system.

Identification of hazardous organic compounds in e-waste plastic using non-target and suspect screening approaches

End-of-life electric and electronic devices stand as one of the fastest growing wastes in the world and, therefore, a rapidly escalating global concern. A relevant fraction of these wastes corresponds to polymeric materials containing a plethora of chemical additives. Some of those additives fall within the category of hazardous organic compounds (HOCs). Despite the significant advances in the capabilities of analytical methods, the comprehensive characterization of WEEE plastic remains as a challenge. This research strives to identify the primary additives within WEEE polymers by implementing a non-target and suspect screening approach. Gas chromatography coupled to time-of-flight mass spectrometry (GC-QTOF-MS), using electron ionization (EI), was applied for the detection and identification of more than 300 substances in this matrix. A preliminary comparison was carried out with nominal resolution EI-MS spectra contained in the NIST17 library. BPA, flame retardants, UV-filters, PAHs, and preservatives were among the compounds detected. Fifty-one out of 300 compounds were confirmed by comparison with authentic standards. The study establishes a comprehensive database containing m/z ratios and accurate mass spectra of characteristic compounds, encompassing HOCs. Semi-quantification of the predominant additives was conducted across 48 WEEE samples collected from handling and dismantling facilities in Galicia. ABS plastic demonstrated the highest median concentrations, ranging from 0.154 to 4456 μg g-1, being brominated flame retardants and UV filters, the families presenting the highest concentrations. Internet router devices revealed the highest concentrations, containing a myriad of HOCs, such as tetrabromobisphenol A (TBBPA), tribromophenol (TBrP), triphenylphosphate (TPhP), tinuvin P and bisphenol A (BPA), most of which are restricted in Europe.

Evidence of promoting effects of 6:2 Cl-PFESA on hepatocellular carcinoma proliferation in humans: An ideal alternative for PFOS in terms of environmental health?

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are synthetic chemicals, encompassing compounds like perfluorooctane sulfonate (PFOS), which have widespread applications across various industries, including food packaging and firefighting. In recent years, China has increasingly employed 6:2 Cl-PFESA as an alternative to PFOS. Although the association between PFAS exposure and hepatocellular carcinoma (HCC) has been demonstrated, the underlying mechanisms that promote HCC proliferation are uncleared. Therefore, we aimed to investigate the effects and differences of PFOS and 6:2 Cl-PFESA on HCC proliferation through in vivo and in vitro tumor models. Our results reveal that both PFOS and 6:2 Cl-PFESA significantly contribute to HCC proliferation in vitro and in vivo. Exposure led to reduced population doubling times, enlarged cell colony sizes, enhanced DNA synthesis efficiency, and a higher proportion of cells undergoing mitosis. Furthermore, both PFOS and 6:2 Cl-PFES) have been shown to activate the PI3K/AKT/mTOR signaling pathway and inhibit necroptosis. This action consequently enhances the proliferation of HCC cells. Our phenotypic assay findings suggest that the tumorigenic potential of 6:2 Cl-PFESA surpasses that of PFOS; in a subcutaneous tumor model using nude mice, the mean tumor weight for the 6:2 Cl-PFESA-treated cohort was 2.33 times that observed in the PFOS cohort (p < 0.01). Despite 6:2 Cl-PFESA being considered a safer substitute for PFOS, the pronounced effects of this chemical on HCC cell growth warrant a thorough assessment of hepatotoxicity risks linked to its usage.

Removing polyfluoroalkyl substances (PFAS) from wastewater with mixed matrix membranes

Polyfluoroalkyl and perfluoroalkyl (PFAS) chemicals are fluorinated and exhibit complicated behavior. They are determined and highly resistant to ecological modifications that render plants ecologically robust. Thermal stability and water and oil resistance are examples of material qualities. Their adverse consequences are causing increasing worry due to their bioaccumulative nature in humans and other creatures. Direct data indicates that PFAS exposure in humans causes endocrine system disruption, immune system suppression, obesity, increased cholesterol, and cancer. Several PFASs are present in drinking water at low doses and may harm people. These cancer-causing PFAS have caused concern for water bodies all around the globe. Analytical techniques are used to identify and measure PFAS in an aqueous medium (membrane). Furthermore, a deeper explanation is provided for PFAS removal methods, including mixed matrix membrane (MMM) technology. By removing over 99 % of the PFAS from wastewater, MMMs may effectively remove PFAS from sewage when the support matrix contains adsorbing components. Furthermore, we consider several factors affecting the removal of PFAS and practical sorption methods for PFAS onto various adsorbents.

The association between per- and polyfluoroalkyl substances (PFASs) and brain, esophageal, melanomatous skin, prostate, and lung cancer using the 2003-2018 US National Health and Nutrition Examination Survey (NHANES) datasets

Introduction

The purpose of this study was to use the US National Health and Nutrition Examination Survey (NHANES) datasets to examine potential relationships between four per- and polyfluoroalkyl substance (PFAS) exposures and each type of cancer, specifically perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA).

Methods

A logistic regression analysis was performed. A directed acyclic graph was plotted to adjust for the potential confounders.

Results

The odds ratio (OR) of brain cancer for a one-unit increase in ln (PFHxS) was 8.16 (95 % confidence interval [CI] 2.98-68.89). The OR of esophageal cancer for one unit increase of ln (PFOA) and ln (PFOS) was 5.10 (95 % CI 1.18-17.34) and 3.97 (95 % CI 1.24-11.42), respectively. The OR of melanoma for one unit increase of ln (PFOA) and ln (PFHxS) was 1.65 (95 % CI 1.07-2.58) and 1.55 (95 % CI 1.07-2.25), respectively. The OR of prostate cancer for one unit increase of ln (PFOS) and ln (PFNA) was 1.21 (95 % CI 1.00-1.48) and 1.27 (95 % CI 1.00-1.62), respectively. The OR of lung cancer for one unit increase of ln (PFOS) and ln (PFNA) was 2.62 (95 % CI 1.24-5.83) and 2.38 (95 % CI 1.00-5.52), respectively.

Discussion

Considering that brain, esophageal, and melanomatous skin cancers have not been targets of epidemiologic studies regarding PFAS exposure, future studies could target these cancers as outcomes of interest.

Environment relevant exposure of perfluorooctanoic acid accelerates the growth of hepatocellular carcinoma cells through mammalian target of rapamycin (mTOR) signal pathway

Perfluorooctanoic acid (PFOA), a synthetic alkyl chain fluorinated compound, has emerged as a persistent organic pollutant of grave concern, casting a shadow over both ecological integrity and humans. Its insidious presence raises alarms due to its capacity to bioaccumulate within the human liver, potentially paving the treacherous path toward liver cancer. Yet, the intricate mechanisms underpinning PFOA's role in promoting the growth of hepatocellular carcinoma (HCC) remain shrouded in ambiguity. Here, we determined the proliferation and transcription changes of HCC after PFOA exposure through integrated experiments including cell culture, nude mice tests, and colony-forming assays. Based on our findings, PFOA effectively promotes the proliferation of HCC cells within the experimental range of concentrations, both in vivo and in vitro. The proliferation efficiency of HCC cells was observed to increase by approximately 10% due to overexposure to PFOA. Additionally, the cancer weight of tumor-bearing nude mice increased by 87.0% (p < 0.05). We systematically evaluated the effects of PFOA on HCC cells and found that PFOA's exposure can selectively activate the PI3K/AKT/mTOR/4E-BP1 signaling pathway, thereby playing a pro-cancer effect on HCC cells Confirmation echoed through western blot assays and inhibitor combination analyses. These insights summon a response to PFOA's dual nature as both an environmental threat and a promoter of liver cancer. Our work illuminates the obscured domain of PFOA-induced hepatoxicity, shedding light on its ties to hepatocellular carcinoma progression.

Risk assessment and partitioning behavior of PFASs in environmental matrices from an e-waste recycling area

OBJECTIVE

Perfluoroalkyl and polyfluoroalkyl substance (PFAS) contamination and their human exposure risks are a major concern. However, knowledge of PFAS contamination in environments near e-waste recycling sites and their health risk assessment are scarce.

METHODS

We measured the concentrations of PFASs in soil (n = 12), water (n = 12) and atmospheric samples (n = 26) by LCP-MS/MS, analyzed the source apportionment of PFASs by PCA, and investigated the child health risk assessment from an e-waste recycling area (Guiyu) and a reference area (Haojiang).

RESULTS

We found high concentrations of PFASs in the atmosphere and low concentrations of PFASs in soil. The average concentration of perfluoro-n-heptanoic acid (PFHpA) (9.43 ng/L) was highest among PFASs in water. The concentrations PFASs in the atmosphere and water were higher in the e-waste recycling area than in the reference area (p < 0.05). According to Multi-Linear regression model, we found that daily intake doses for PFASs in air of PFODA [β (95 % CI): -0.217 (-0.332, -0.048), p < 0.05] and PFBS [β (95 % CI): -0.064 (-0.106, -0.006), p < 0.05] were negatively associated with child BMI. PFBA [β (95 % CI: -1.039 (-2.454, -0.010), p < 0.05] was negatively correlated with child head circumference.

CONCLUSION

The concentrations of PFASs in the water and atmosphere are higher in the e-waste recycling site than in the reference area. We found that their intake affected growth and development in children. We need to reduce pollution from PFASs in the e-waste recycling area while maintaining a focus on their impact on child health.

A critical review of perfluoroalkyl and polyfluoroalkyl substances (PFAS) landfill disposal in the United States

Landfills manage materials containing per- and polyfluoroalkyl substances (PFAS) from municipal solid waste (MSW) and other waste streams. This manuscript summarizes state and federal initiatives and critically reviews peer-reviewed literature to define best practices for managing these wastes and identify data gaps to guide future research. The objective is to inform stakeholders about waste-derived PFAS disposed of in landfills, PFAS emissions, and the potential for related environmental impacts. Furthermore, this document highlights data gaps and uncertainties concerning the fate of PFAS during landfill disposal. Most studies on this topic measured PFAS in liquid landfill effluent (leachate); comparatively fewer have attempted to estimate PFAS loading in landfills or other effluent streams such as landfill gas (LFG). In all media, the reported total PFAS heavily depends on waste types and the number of PFAS included in the analytical method. Early studies which only measured a small number of PFAS, predominantly perfluoroalkyl acids (PFAAs), likely report a significant underestimation of total PFAS. Major findings include relationships between PFAS effluent and landfill conditions - biodegradable waste increases PFAS transformation and leaching. Based on the results of multiple studies, it is estimated that 84% of PFAS loading to MSW landfills (7.2 T total) remains in the waste mass, while 5% leaves via LFG and 11% via leachate on an annual basis. The environmental impact of landfill-derived PFAS has been well-documented. Additional research is needed on PFAS in landfilled construction and demolition debris, hazardous, and industrial waste in the US.

Concentrations and co-occurrence of 101 emerging and legacy organic pollutants in the ultrafine, fine and coarse fractions of airborne particulates associated with treatment of waste from electrical and electronic equipment

Occupational exposure to airborne particles can increase the development of morbidity, also because of the chemical composition of particulate matter (PM). In workplace, where manual and mechanical disassembly of electric and electronic equipment (EEE) take place, there are evident risks of respiratory exposure to a great number of different toxic organic compounds present in the electrical and plastic materials of which the equipment is made. Airborne particles are numerous, cover a wide range of sizes and are rich in toxic organic compounds. In the present work, a sampling program was conducted and ultrafine, fine and coarse airborne particles were collected in three EEE waste treatment plants. Afterwards, the extraction and analysis of polycyclic aromatic hydrocarbons (PAHs), their nitro and oxygenated derivatives (nitroPAHs, oxyPAHs), organophosphorus compounds (OPEs), Brominated Flame Retardants (BFRs), polychlorinated biphenyls (PCBs), Polybrominated Diphenyl Ethers (PBDEs), and polyfluoralkyl substances (PFASs) was performed. The percentage ratio of the mass of organic compounds and the mass of the ultrafine fraction of PM (PM0.1) was higher than those of the fine and coarse fractions. Even with low concentrations, the co-occurrence of numerous potentially toxic compounds capable of easily reaching other organs passing by the lung vasculature, through the lymph makes the working environment unhealthy.

The decomposition and emission factors of a wide range of PFAS in diverse, contaminated organic waste fractions undergoing dry pyrolysis

Current treatment options for organic waste contaminated with per- and polyfluoroalkyl substances (PFAS) are generally limited to incineration, composting or landfilling, all resulting in emissions. Dry pyrolysis is a promising emerging alternative to these practices, but there is uncertainty related to the fate of PFAS during this process. The present work first developed a robust method for the determination of PFAS in complex matrices, such as sewage sludge and biochar. Then, a mass balance was established for 56 different PFAS during full-scale pyrolysis (2-10 kg biochar hr^-1, 500-800 °C) of sewage sludges, food waste reject, garden waste and waste timber. PFAS were found in all wastes (56-3651 ng g^-1), but pyrolysis resulted in a ≥ 96.9% removal. Residual PFAS (0.1-3.4 ng g^-1) were detected in biochars obtained at temperatures up to 750 °C and were dominated by long chain PFAS. Emitted PFAS loads ranged from 0.01 to 3.1 mg tonne^-1 of biochar produced and were dominated by short chain PFAS. Emissions made up < 3% of total PFAS-mass in the wastes. Remaining uncertainties are mainly related to the presence of thermal degradation products in flue gas and condensation oils.

Lithium-ion battery recycling: a source of per- and polyfluoroalkyl substances (PFAS) to the environment?

Recycling of lithium-ion batteries (LIBs) is a rapidly growing industry, which is vital to address the increasing demand for metals, and to achieve a sustainable circular economy. Relatively little information is known about the environmental risks posed by LIB recycling, in particular with regards to the emission of persistent (in)organic fluorinated chemicals. Here we present an overview on the use of fluorinated substances - in particular per- and polyfluoroalkyl substances (PFAS) - in state-of-the-art LIBs, along with recycling conditions which may lead to their formation and/or release to the environment. Both organic and inorganic fluorinated substances are widely reported in LIB components, including the electrodes and binder, electrolyte (and additives), and separator. Among the most common substances are LiPF6 (an electrolyte salt), and the polymeric PFAS polyvinylidene fluoride (used as an electrode binder and a separator). Currently the most common LIB recycling process involves pyrometallurgy, which operates at high temperatures (up to 1600 °C), sufficient for PFAS mineralization. However, hydrometallurgy, an increasingly popular alternative recycling approach, operates under milder temperatures (<600 °C), which could favor incomplete degradation and/or formation and release of persistent fluorinated substances. This is supported by the wide range of fluorinated substances detected in bench-scale LIB recycling experiments. Overall, this review highlights the need to further investigate emissions of fluorinated substances during LIB recycling and suggests that substitution of PFAS-based materials (i.e. during manufacturing), or alternatively post-treatments and/or changes in process conditions may be required to avoid formation and emission of persistent fluorinated substances.

Firefighters' exposure to per-and polyfluoroalkyl substances (PFAS) as an occupational hazard: A review

The term "firefighter" and "cancer" have become so intertwined in the past decade that they are now nearly inseparable. Occupational exposure of firefighters to carcinogenic chemicals may increase their risk of developing different types of cancer. PFAS are one of the major classes of carcinogenic chemicals that firefighters are exposed to as occupational hazard. Elevated levels of PFAS have been observed in firefighters' blood serum in recent studies. Possible sources of occupational exposure to PFAS include turnout gear, aqueous film-forming foam, and air and dust at both the fire scene and fire station. Preliminary discussion on PFAS includes definition, classification, and chemical structure. The review is then followed by identifying the sources of PFAS that firefighters may encounter as an occupational hazard. The structural properties of the PFAS used in identified sources, their degradation, and exposure pathways are reviewed. The elevated level of PFAS in the blood serum and how this might associate with an increased risk of cancer is discussed. Our review shows a significant amount of PFAS on turnout gear and their migration to untreated layers, and how turnout gear itself might be a potential source of PFAS exposure. PFAS from aqueous film-forming foams (AFFF), air, and dust of fire stations have been already established as potential exposure sources. Studies on firefighters' cancer suggest that firefighters have a higher cancer risk compared to the general population. This review suggests that increased exposure to PFAS as an occupational hazard could be a potential cancer risk for firefighters.

The Association of Combined Per- and Polyfluoroalkyl Substances and Metals with Allostatic Load Using Bayesian Kernel Machine Regression

Background/Objective: This study aimed to investigate the effect of exposure to per- and polyfluoroalkyl substances (PFAS), a class of organic compounds utilized in commercial and industrial applications, on allostatic load (AL), a measure of chronic stress. PFAS, such as perfluorodecanoic acid (PFDE), perfluorononanoic acid (PFNA), perfluorooctane sulfonic acid (PFOS), perfluoroundecanoic acid (PFUA), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHS), and metals, such as mercury (Hg), barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), molybdenum (Mo), lead (Pb), antimony (Sb), thallium (TI), tungsten (W), and uranium (U) were investigated. This research was performed to explore the effects of combined exposure to PFAS and metals on AL, which may be a disease mediator. Methods: Data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2014 were used to conduct this study on persons aged 20 years and older. A cumulative index of 10 biomarkers from the cardiovascular, inflammatory, and metabolic systems was used to calculate AL out of 10. If the overall index was ≥ 3, an individual was considered to be chronically stressed (in a state of AL). In order to assess the dose-response connections between mixtures and outcomes and to limit the effects of multicollinearity and other potential interaction effects between exposures, Bayesian kernel machine regression (BKMR) was used. Results: The most significant positive trend between mixed PFAS and metal exposure and AL was revealed by combined exposure to cesium, molybdenum, PFHS, PFNA, and mercury (posterior inclusion probabilities, PIP = 1, 1, 0.854, 0.824, and 0.807, respectively). Conclusions: Combined exposure to metals and PFAS increases the likelihood of being in a state of AL.

Occurrence, partitioning and transport of perfluoroalkyl acids in gas and particles from the southeast coastal and mountainous areas of China

Perfluoroalkyl acids (PFAA) in gas and particles were analyzed in southeast coastal and mountainous cities, including Fuzhou, Xiamen, Zhangzhou and Nanping, to study the pollution characteristics, particle size distribution, phase partitioning and atmospheric transport. PFAA ranged from 7.8 to 290 pg m^-3 in gaseous phase, 27 - 1200 pg m^-3 in particulate phase, and perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA) were main compounds. PFAA had the highest concentration in Nanping with perfluorohexanoic acid (PFHxA) dominant, which could be related to the emission of PFAS from local industrial plants. Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) exhibited different particle size distribution characteristics, with PFSAs preferring to distribute on coarse particles, which could be affected by the salt, minerals and organic matter in different particle sizes. The gas - particle partitioning coefficient (K_PA) had a line relationship with the fluorinated carbon chain length of PFAA, suggesting that long-chain PFAA tended to exist in particulate phase. The Winter Monsoon could transport to the study area and drive atmospheric PFAS to southern cities. HIGHLIGHTS: • Industrial plants contributed high concentrations of PFAA. • PFSAs tended to present in coarse particles. • Log K_PA increased linearly with increasing carbon chain length of PFAA. • Winter Monsoon drove atmospheric PFAA to southern cities.

Global research into the relationship between electronic waste and health over the last 10 years: A scientometric analysis

Introduction

The aims of this research were to conduct the first holistic and deep scientometric analysis of electronic waste and health and provide with the prediction of research trends and hot topics.

Method

A comprehensive literature search was conducted via the Web of Science Core collection databases on 26 August 2022 to identify all articles related to electronic waste and health. A total of 652 records have been extracted from the Web of Science after applying inclusion and exclusion criteria and were analyzed using bibliometrix software of R-package, VOSviewer, and CiteSpace, visualized by tables and diagrams.

Result

The number of publications and total citations had shown a general growth trend from 2012 to 2021, with an average annual growth rate of 23.74%. Mainland China was the significant nation with the greatest number of publications, citations, and international links. The journal publishing the most was "Science of the Total Environment" (n = 56). Huo X and Hu XJ were the top two author contributing to this field with the highest h-index (23). Over time, the focus in this field shifted to exposure to heavy metal, polychlorinated biphenyls, polybrominated biphenyl ethers, and poly- and perfluorinated alkyl substances from electronic waste, and managements, such as hydrometallurgy.

Discussion

By this scientometric analysis, we found that the most active country, journal, organization and author contributing to this filed, as well as high impact documents and references and research hotspots. Also, we found that the hotspots might be exposure to toxic substances from electronic waste procession, its impact on human health and relevant managements. And evironmentally friendly materials to replace heavy metal mate rials, and environmentally friendly and effective recycling methods of electronic waste need to be further studied.

First Evidence of Prenatal Exposure to Emerging Poly- and Perfluoroalkyl Substances Associated with E-Waste Dismantling: Chemical Structure-Based Placental Transfer and Health Risks

Limited information is available about prenatal exposure to per- and polyfluoroalkyl substances (PFAS) in electronic waste (e-waste) recycling sites. In this study, we determined 21 emerging PFAS and 13 legacy PFAS in 94 paired maternal and cord serum samples collected from an e-waste dismantling site in Southern China. We found 6:2 fluorotelomer sulfonate (6:2 FTSA), 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), and perfluorooctanephosphonate (PFOPA) as the major emerging PFAS, regardless of matrices, at median concentrations of 2.40, 1.78, and 0.69 ng/mL, respectively, in maternal serum samples, and 2.30, 0.73, and 0.72 ng/mL, respectively, in cord serum samples. Our results provide evidence that e-waste dismantling activities contribute to human exposure to 6:2 FTSA, 6:2 Cl-PFESA, and PFOPA. The trans-placental transfer efficiencies of emerging PFAS (0.42-0.94) were higher than that of perfluorooctanesulfonic acid (0.37) and were structure-dependent. The substitution of fluorine with chlorine or hydrogen and/or hydrophilic functional groups may alter trans-placental transfer efficiencies. Multiple linear regression analysis indicated significant associations between maternal serum concentrations of emerging PFAS and maternal clinical parameters, especially liver function and erythrocyte-related biomarkers. This study provides new insights into prenatal exposure to multiple PFAS in e-waste dismantling areas and the prevalence of emerging PFAS in people living near the sites.