Brominated flame retardants and perfluorinated compounds in indoor dust from homes and offices in Flanders, Belgium

Levels and spatial profile of per- and polyfluoroalkyl substances in edible shrimp products from Japan and neighboring countries; a potential source of dietary exposure to humans

Exposure to per- and polyfluoroalkyl substances (PFAS) is of great concern for human health because of their persistence and potentially adverse effects. Dietary intake, particularly through aquatic products, is a significant route of human exposure to PFAS. We analyzed perfluoroalkyl sulfonic acid (PFSA with carbon numbers from 6 to 8 and 10 (C６-C8, C10)) and perfluorooctanesulfonamide (FOSA), and perfluoroalkyl carboxylic acid (PFCA with carbon numbers from 6 to 15 (C6-C15)) in 30 retail packs of edible shrimps, which included seven species from eight coastal areas of Japan and neighboring countries. The most prevalent compounds were perfluorooctane sulfonate (PFOS, C8) and perfluoroundecanoic acid (PFUnDA, C11), accounting for 46 % of total PFAS. The concentrations ranged from 6.5 to 44 ng/g dry weight (dw) (equivalent to 1.5 to 10 ng/g wet weight (ww)) and varied according to species and location. For example, Alaskan pink shrimp (Pandalus eous) from the Hokuriku coast, Japan contained high levels of long-chain PFCAs (38 ng/g dw (equivalent to 8.7 ng/g ww)), while red rice prawn (Metapenaeopsis barbata) from Yamaguchi, Japan contained a high concentration of PFOS (29 ng/g dw (equivalent to 6.7 ng/g ww)). We also observed regional differences in the PFAS levels with higher concentrations of long-chain PFCAs in Japanese coastal waters than in the South China Sea. The PFAS profiles in shrimp were consistent with those in the diet and serum of Japanese consumers, suggesting that consumption of seafood such as shrimp may be an important source of exposure. The estimated daily intake of sum of all PFAS from shrimp from Japanese coastal water was 0.43 ng/kg body weight/day in average, which could reach the weekly tolerable values (4.4 ng/kg body weight /week) for the sum of the four PFSA set by the EFSA for heavy consumers. The high concentration of PFAS in shrimp warrants further investigation.

HBM4EU E-waste study: Assessing persistent organic pollutants in blood, silicone wristbands, and settled dust among E-waste recycling workers in Europe

E-waste recycling is an increasingly important activity that contributes to reducing the burden of end-of-life electronic and electrical apparatus and allows for the EU's transition to a circular economy. This study investigated the exposure levels of selected persistent organic pollutants (POPs) in workers from e-waste recycling facilities across Europe. The concentrations of seven polychlorinated biphenyls (PCBs) and eight polybrominated diphenyl ethers (PBDEs) congeners were measured by GC-MS. Workers were categorized into five groups based on the type of e-waste handled and two control groups. Generalized linear models were used to assess the determinants of exposure levels among workers. POPs levels were also assessed in dust and silicone wristbands (SWB) and compared with serum. Four PCB congeners (CB 118, 138, 153, and 180) were frequently detected in serum regardless of worker's category. With the exception of CB 118, all tested PCBs were significantly higher in workers compared to the control group. Controls working in the same company as occupationally exposed (Within control group), also displayed higher levels of serum CB 180 than non-industrial controls with no known exposures to these chemicals (Outwith controls) (p < 0.05). BDE 209 was the most prevalent POP in settled dust (16 μg/g) and SWB (220 ng/WB). Spearman correlation revealed moderate to strong positive correlations between SWB and dust. Increased age and the number of years smoked cigarettes were key determinants for workers exposure. Estimated daily intake through dust ingestion revealed that ΣPCB was higher for both the 50th (0.03 ng/kg bw/day) and 95th (0.09 ng/kg bw/day) percentile exposure scenarios compared to values reported for the general population. This study is one of the first to address the occupational exposure to PCBs and PBDEs in Europe among e-waste workers through biomonitoring combined with analysis of settled dust and SWB. Our findings suggest that e-waste workers may face elevated PCB exposure and that appropriate exposure assessments are needed to establish effective mitigation strategies.

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Occurrence and dietary intake of dioxins, furans (PCDD/Fs), PCBs, and flame retardants (PBDEs and HBCDDs) in baby food and infant formula

This study determines the levels of 49 persistent organic pollutants which were grouped into polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDDs), in infant formula and varieties of baby food. The analyzed samples (n = 80) came from stores all over Poland. The presence of PCDD/F, PCDD/F/PCB and non dioxin-like (ndl)-PCB congeners above the maximum levels stipulated in Commission Regulation (EU) No 1259/2011 was not detected in any sample. The determined average content of PCDD/Fs/dl-PCBs in the tested baby foods was in the range of 4-10 % of the maximum level, and content of ndl-PCBs was in the range of 2-6 % of the maximum level. Despite these low levels of dioxins, furans, and PCBs, a risk analysis assuming weekly consumption of the recommended food intake showed exceedances of the tolerable weekly intake (TWI). The content of flame retardants was low in all examined categories of food for children and infant formula. The lower-bound concentration of the sum of HBCDD isomers (LB ∑HBCDDs) ranged from below the limit of quantification (LOQ) to 0.0313 ng/g w.w. and the concentration of ∑PBDEs was in a 0.001-1.014 ng/g w.w. range. Neither infant formula nor baby food contributed considerably to infant exposure to HBCDDs or PBDEs. Our research indicates that the safe exposure thresholds for dioxins and PCBs in foods for infants and young children may be too high and perhaps it may be necessary to amend the legislation setting acceptable limits for baby food. It seems reasonable to introduce a recommendation on the frequency of food consumption for children and the control of raw materials for food production, in particular fish and cow milk, should be a permanent control point in the food safety assurance system.

Eight novel brominated flame retardants in indoor and outdoor dust samples from the E-waste recycling industrial park: Implications for human exposure

As alternatives for legacy brominated flame retardants, novel brominated flame retardants (NBFRs) have a wide array of applications in the electronic and electrical fields. The shift of recycling modes of electronic and electrical waste (e-waste) from informal recycling family workshop to formal recycling facilities might come with the change the chemical landscape emitted including NBFRs, however, little information is known about this topic. This study investigated the occurrence characteristics, distribution, and exposure profiles of eight common NBFRs and their derivatives in an e-waste recycling industrial park in central China and illustrated the differences in various functional zones in the recycling park. The highest level of ΣNBFRs in dust samples was found in e-waste storage area at median concentration of 27,400 ng/g, followed by e-waste dismantling workshops (23,300 ng/g), workshop outdoor area (7770 ng/g), and residential area outdoor (536 ng/g). In the e-waste dismantling associated dust samples, tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), tetrabromobisphenol A (TBBPA) and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) were the predominant components. This paper presented the first evidence regarding the occurrence characteristic and distribution of tetrabromobisphenol S (TBBPS), tetrabromobisphenol A bismethyl ether (TBBPA-BME) and tetrabromobisphenol S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE) in the e-waste associated dust samples. By comparing with previous studies performed in China, this paper also noticed the significant decrease of TBBPA concentrations in the dust probably due to the shift of e-wastes sources and recycling modes. We further assessed the risk of occupational workers exposure to NBFRs. The median EDI (estimated daily intake) value of ΣNBFRs among e-waste dismantling workers was 9.71 ng/kg BW/d with the maximum EDI value being 19.6 ng/kg BW/d, hundreds of times higher than those exposed by general population. The study raises great concern for the health risk of occupational exposure to NBFRs in the e-waste recycling industrial park.

Occupational exposure to per- and polyfluoroalkyl substances: a scope review of the literature from 1980-2021

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) comprise a large group of chemicals that have been integrated into a wide variety of industrial processes and consumer products since the 1950s. Due to their profuse usage and high persistence in human serum, understanding workplace exposures to PFAS is critical.

OBJECTIVE

We aimed to characterize the PFAS exposure profiles of relevant occupational populations, elucidate trends in the PFAS exposure characterization process, and identify major research gaps that remain within the occupational PFAS exposure literature.

METHODS

A systematic search of four literature databases for peer-reviewed articles published between 1980 and 2021 on PFAS exposure in occupational settings was conducted.

RESULTS

Of the 2574 articles identified, 92 met the inclusion criteria. Fluorochemical workers were the target population in most early exposure assessment research; however, studies conducted within the last 10 years have evaluated a wider range of occupational populations and settings. The highest exposures were reported in fluorochemical workers, but, in comparison to reference populations, one or more PFAS were elevated in most workers and in most workplaces that were assessed. PFAS was most frequently assessed in worker serum using a discrete analytical panel of PFAS, with earlier studies restricted to a few long-alkyl chain PFAS while more recent studies have included more expansive panels due to more robust methods.

SIGNIFICANCE

Characterization of occupational exposure to PFAS is limited but expanding. Current analytical methods are not robust enough to fully capture the potential range of PFAS present across different workers and workplaces. While exposures to PFAS for certain occupational groups have been studied in detail, exposure information for other occupational groups with high potential for exposure are limited. This review highlights substantial findings and major research gaps within the occupational literature.

EI/IOT of PFCs: Environmental impacts/interactions, occurrences, and toxicities of perfluorochemicals

Various studies have been conducted on the perfluorochemicals (PFCs) family over the years. These compounds have been sought in various industrial aspects involving the synthesis of everyday utilities due to their broad range of applications. As a result, PFCs have built up in the environment, causing concern. The presence of PFCs in various environmental media, such as terrestrial and marine settings, as well as the mechanisms of transport, bioaccumulation, and physio-chemical interactions of PFCs within plants, aquatic organisms, microplastics, and, ultimately, the human body, are discussed in this review, which draws on a variety of research publications. The interaction of PFCs with proteins, translocation, and adsorption by hydrophobic interactions were observed, and this had an impact on the natural functioning of biological processes, resulting in events such as phylogenic clustering, competitive inhibition, and many others, posing potential hazards to human health and other relevant organisms in the ecosystem. However, further research is needed to have a better knowledge of PFCs and their interactions so that low-cost treatments can be developed to eliminate them. It is therefore, future research should focus on the role of soil matrix as a defensive mechanism for PFCs, as well as the impact of PFC chain length rejection.

Evaluating the dynamic distribution process and potential exposure risk of chlorinated paraffins in indoor environments of Beijing, China

Chlorinated paraffins (CPs) are typical semi-volatile chemicals (SVOCs) that have been used in copious quantities in indoor material additives. SVOCs distribute dynamically between the gas phase and various condensate phases, especially organic films. Investigating the dynamic behaviors of existing CPs in indoor environments is necessary for understanding their potential risk to humans from indoor exposure. We investigate the distribution profiles of CPs in both gas phase and organic films in indoor environments of residential buildings in Beijing, China. The concentrations of CPs were in the range of 32.21-1447 ng/m³ in indoor air and in the range of 42.30-431.1 μg/m² and in organic films. Cooking frequency was identified as a key factor that affected the distribution profiles of CPs. Furthermore, a film/gas partitioning model was constructed to explore the transportation and fate of CPs. Interestingly, a re-emission phenomenon from organic films was observed for chemical groups with lower log K_oa components, and, importantly, their residue levels in indoor air were well predicted. The estimated exposure risk of CPs in indoor environment was obtained. For the first time, these results produced convincing evidence that the co-exposure risk of short-chain CPs (SCCPs), medium-chain CPs (MCCPs), and long-chain CPs (LCCPs) in indoor air could be further increased by film/gas distribution properties, which is relevant for performing risk assessments of exposure to these SVOCs in indoor environments.

Ellie A, Dong H, Ahmad UM. Health Effects of Exposure to Indoor Semi-Volatile Organic Compounds in Chinese Building Environment: A Systematic Review

People spend a considerable portion of their lives indoors; thus, the quality of the indoor environment is crucial. Semi-volatile organic compounds (SVOCs) are among the primary indoor pollutants responsible for various health risks. This paper systematically reviews the impact of SVOC exposure on human health in Chinese built environments. Based on a set of criteria, we judged 12 publications as providing sufficient information on both SVOC exposure and health effects to inform the relationship. Out of six studies on polycyclic aromatic hydrocarbons (PAHs), three observed a positive association between PAH exposure and lung cancer. Out of six studies of phthalate exposure, two studies reported a significant positive association between DEP and DiBP and asthma, between DEP and DEHP and dry cough among children, and between DBP and rhinitis among younger adults. The results of this review suggest that there might be a link between phthalate exposure and asthma and allergies, as well as a link between PAH exposure and lung cancer. However, due to the limited number of studies conducted, more evidence is necessary to definitively guide the establishment of standards for SVOC control in China.

Seasonal variation of short-, medium- and long-chain chlorinated paraffin distribution in Belgian indoor dust

Chlorinated paraffins (CPs) are high production volume plasticizers and flame retardants, which have exhibited bioaccumulative and toxic properties. CPs may be released from treated consumer goods and bind with indoor dust, leading to human exposure via unintentional dust ingestion. In this study, the concentrations and homologue distribution of CPs were measured in 50 indoor dust samples collected in paired winter and summer sampling campaigns from 25 homes in Flanders, Belgium. Short-, medium- and long-chain CPs (SCCPs (C_10-13), MCCPs (C_14-17) and LCCPs (C_18-20), respectively) were each detected in all Belgian indoor dust samples with overall median concentrations of 6.1 µg/g (range 0.61 to 120 µg/g), 45 µg/g (range 4.5 to 520 µg/g) and 4.5 µg/g (range 0.3 to 50 µg/g), respectively. Concentrations were significantly higher in the winter samples than summer for each of the three groups (p < 0.05). LCCPs homologues ranging from C_21-32 were also detected in dust samples and accounted for approximately half of the LCCP relative abundance based on instrumental peak area, although a lack of appropriate analytical standards prevented quantification of these homologues. While clear sources of CP contamination in dust could not be identified, significant associations between concentrations of ∑SCCPs, ∑MCCPs and ∑LCCPs (C_18-20) (p < 0.05) suggested the combined application within materials or products in homes. Based on typical exposure scenarios, estimated daily intake of ∑CPs (C_10-20) for adults and toddlers were 14 and 270 ng/kg bw/day, respectively, though margin of exposure assessments for SCCPs and MCCPs indicated that adverse health effects were unlikely for all exposure scenarios. This study presents the first evidence of seasonal variation in the levels and distribution for each of the SCCP, MCCP and LCCP classes in indoor dust and highlights the urgent need for appropriate analytical standards for LCCP quantification.

Bioavailability of inhaled or ingested PFOA adsorbed to house dust

Indoor environments may impact human health due to chemical pollutants in the indoor air and house dust. This study aimed at comparing the bioavailability and distribution of PFOA following both an inhalation and an oral exposure to PFOA coated house dust in rats. In addition, extractable organofluorine (EOF) was measured in different tissue samples to assess any potential influence of other organofluorine compounds in the experimental house dust. Blood samples were collected at sequential time points after exposure and at the time of termination; the lungs, liver, and kidney were collected for quantification of PFOA and EOF. The concentration of PFOA in plasma increased rapidly in both exposure groups attaining a C_max at 3 h post exposure. The C_max following inhalation was four times higher compared to oral exposures. At 48 h post exposure, the levels of PFOA in the plasma, liver, and kidney were twice as high from inhalation exposures. This shows that PFOA is readily bioavailable and has a rapid systemic distribution following an inhalation or oral exposure to house dust coated with PFOA. The proportion of PFOA to EOF corresponded to 65-71% and 74-87% in plasma and tissues, respectively. The mass balance between EOF and target PFOA indicates that there might be other unknown PFAS precursor and/or fluorinated compounds that co-existed in the house dust sample that can have accumulated in rats.

Occurrence of persistent organic pollutants (POPs) in the atmosphere of South Korea: A review

Numerous studies found the presence of persistent organic pollutants (POPs) in various environmental compartments, including air, water, and soil. POPs have been discovered in various industrial and agricultural products with severe environmental and human health consequences. According to the data, South Korea is a hotspot for POP pollution in the southern part of Asia; hence, South Korea has implemented the Stockholm Convention's National Implementation Plan (NIP) to address this worldwide issue. The purpose of this review is to assess the distribution pattern of POPs pollution in South Korea's atmosphere. According to findings, PAHs, PCBs, BFRs, and PBDEs significantly polluted the atmosphere of South Korea; however, assessing their exposure nationwide is difficult due to a shortage of data. The POPs temporal trend and meta-analysis disclosed no proof of a decrease in PAHs and BFRs residues in the atmosphere. However, POP pollution in South Korea tends to decrease compared to contamination levels in neighboring countries like Japan and China.

Review of the environmental occurrence, analytical techniques, degradation and toxicity of TBBPA and its derivatives

BFRs (brominated flame retardants) are a class of compounds that are added to or applied to polymeric materials to avoid or reduce the spread of fire. Tetrabromobisphenol A (TBBPA) is one of the known BFR used many in industries today. Due to its wide application as an additive flame retardant in commodities, TBBPA has become a common indoor contaminant. Recent researches have raised concerns about the possible hazardous effect of exposure to TBBPA and its derivatives in humans and wildlife. This review gives a thorough assessment of the literature on TBBPA and its derivatives, as well as environmental levels and human exposure. Several analytical techniques/methods have been developed for sensitive and accurate analysis of TBBPA and its derivatives in different compartments. These chemicals have been detected in practically every environmental compartment globally, making them a ubiquitous pollutant. TBBPA may be subject to adsorption, biological degradation or photolysis, photolysis after being released into the environment. Treatment of TBBPA-containing waste, as well as manufacturing and usage regulations, can limit the release of these chemicals to the environment and the health hazards associated with its exposure. Several methods have been successfully employed for the treatment of TBBPA including but not limited to adsorption, ozonation, oxidation and anaerobic degradation. Previous studies have shown that TBBPA and its derivative cause a lot of toxic effects. Diet and dust ingestion and have been identified as the main routes of TBBPA exposure in the general population, according to human exposure studies. Toddlers are more vulnerable than adults to be exposed to indoor dust through inadvertent ingestion. Furthermore, TBBP-A exposure can occur during pregnancy and through breast milk. This review will go a long way in closing up the knowledge gap on the silent and over ignored deadly effects of TBBPA and its derivatives and their attendant consequences.

Per-and polyfluoroalkyl substances (PFAS) and persistent chemical mixtures in dust from U.S. colleges

Indoor spaces contain several classes of persistent organic chemicals, including per- and polyfluoroalkyl substances (PFAS), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). However, concentrations of PFAS and persistent chemical mixtures and their associations with building characteristics on college campuses are understudied. We collected dust from 43 nonresidential spaces on four U.S. college campuses in 2016 and evaluated associations of room characteristics (carpeting, upholstered furniture, and years since last furnished) with dust concentrations of PFAS, PBDEs, PCBs, and OCPs. Nine PFAS, twelve PBDEs, two PCBs, and four OCPs were each detected in at least 75% of the spaces, including several chemicals (e.g., DDT) that have been banned for decades. Concentrations were correlated within and, in some cases, between chemical classes. Wall-to-wall carpeting (compared to rooms without wall-to-wall carpeting) was associated with higher concentrations of six individual PFAS and a mixture of PFAS, and the number of pieces of upholstered furniture was associated with increased concentrations of a mixture of PBDEs. These findings indicate that carpeting and furniture are current sources of PFAS and PBDEs, respectively. Building and finish materials should be carefully selected to avoid exposure to persistent chemicals.

Identification of bisphenols and derivatives in greenhouse dust as a potential source for human occupational exposure

Bisphenol A (BPA) and alternative bisphenols are widely used in the industrial production of polycarbonates and resin polymers. Adverse effects on human health have been described for BPA and owing to the structural similarity of alternative bisphenols and derivatives, a similar toxicity profile is expectable. Dust can act as a sink for bisphenols owing to the large surface area to mass ratio. Human risk exposure to bisphenols via indoor dust has been widely assessed in the last decade. The environmental conditions inside greenhouses, among other factors, facilitate that chemicals are released from greenhouse building materials to dust. This study aims to explore for the first time the potential of greenhouse dust as a new source of bisphenols for human exposure. For this purpose, a supramolecular solvent-based method was applied to the extraction of twenty-one bisphenols from greenhouse dust, prior to their determination by liquid chromatography–tandem mass spectrometry. Nineteen bisphenols were found in the five greenhouse dust samples analysed, with concentrations ranging from 5275 ng g⁻¹ (BPA) to 0.25 ng g⁻¹ (trichlorobisphenol A). The average daily dose (ADD) via dust ingestion for bisphenol compounds was calculated, in order to estimate the occupational exposure for inadvertent dust ingestion. Despite the calculated ADD value for BPA (47.81 ng kg⁻¹ day⁻¹) being below the tolerable daily intake proposed by EFSA (4·10³ ng kg⁻¹ day⁻¹), this value was considerably higher than those previously reported for indoor dust, which brings to light the importance of considering greenhouse dust as bisphenols source of exposure for greenhouse workers.

Prevalence and Implications of Per- and Polyfluoroalkyl Substances (PFAS) in Settled Dust

PURPOSE OF REVIEW

Per- and polyfluoroalkyl substances (PFAS) are a family of more than 7,000 fluorinated compounds. The carbon-fluorine bond of PFAS provides desirable hydrophobic and oleophobic properties and stability that has led to widespread usage in consumer products and industrial applications. The strength of the carbon-fluorine bond also prevents appreciable degradation once released into the environment. Consequently, various household products can release volatile and nonvolatile PFAS into the indoor environment that often concentrate in dust. We discuss the diversity of PFAS in settled dust, emission sources of these chemicals, changes in PFAS profiles in dust over the past century, and the implications for human health.

RECENT FINDINGS

Sources of PFAS found in dust include building materials and furnishings and consumer products used in typical indoor spaces. Daycares and workplaces are emphasized as locations with widespread exposure due to the presence of treated carpeting and industrial-strength cleaners. Comparison and interpretation of findings across studies are complicated by the different ways in which PFAS are screened across studies. We further discuss recent developments in non-targeted software for the comprehensive annotation of PFAS in indoor dust and emphasize the need for comprehensive and harmonized analytical workflows. We highlight the detection and diversity of PFAS in settled dust collected from various indoor spaces, including locations with vulnerable subpopulations. There are opportunities for future research to leverage settled dust as a sentinel environmental matrix to evaluate the link between inhalation and ingestion routes of PFAS exposure to adverse health.

Toxic organic pollutants in Greek house dust: Implications for human exposure and health risk

Organic contaminants often documented in house dust include mainly chemicals released from construction materials and consumer products and compounds emitted from indoor combustion activities. The occurrence of major chemical classes of toxic organic pollutants, included polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and nitrated polycyclic aromatic hydrocarbons (NPAHs), was for the first time investigated in house dust in Greece. The mean concentrations of ∑₁₆PAHs, ∑₂₀PBDEs, ∑₇NPAHs and∑₁₅PCBs in house dust were 4650 ng g^-1, 564 ng g^-1, 7.52 ng g^-1, and 6.29 ng g^-1, respectively. Exposure to dust organic contaminants via ingestion, inhalation and dermal absorption was estimated for two age classes (adults and children) and carcinogenic and non-carcinogenic risks were assessed. The hazard index (HI) for adults and children for PBDEs, PCBs, PAHs and NPAHs in all samples was less than 1 suggesting a very low level of concern for all human age group due to exposure to those chemicals. Total carcinogenic risk via the three exposure pathways (ingestion, inhalation and dermal contact) was within the safe range of 10^-6 to 10^-4.

Chemical contaminant exposures assessed using silicone wristbands among occupants in office buildings in the USA, UK, China, and India

Little is known about chemical contaminant exposures of office workers in buildings globally. Complex mixtures of harmful chemicals accumulate indoors from building materials, building maintenance, personal products, and outdoor pollution. We evaluated exposures to 99 chemicals in urban office buildings in the USA, UK, China, and India using silicone wristbands worn by 251 participants while they were at work. Here, we report concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs), organophosphate esters (OPEs), phthalates and phthalate alternatives, pesticides, and polycyclic aromatic hydrocarbons (PAHs). First, we found major differences in office worker chemical exposures by country, some of which can be explained by regulations and use patterns. For example, exposures to several pesticides were substantially higher in India where there were fewer restrictions and unique malaria challenges, and exposures to flame retardants tended to be higher in the USA and UK where there were historic, stringent furniture flammability standards. Higher exposures to PAHs in China and India could be due to high levels of outdoor air pollution that penetrates indoors. Second, some office workers were still exposed to legacy PCBs, PBDEs, and pesticides, even decades after bans or phase-outs. Third, we identified exposure to a contemporary PCB that is not covered under legacy PCB bans due to its presence as an unintentional byproduct in materials. Fourth, exposures to novel BFRs, OPEs, and other chemicals commonly used as substitutes to previously phased-out chemicals were ubiquitous. Fifth, some exposures were influenced by individual factors, not just countries and buildings. Phthalate exposures, for example, were related to personal care product use, country restrictions, and building materials. Overall, we found substantial country differences in chemical exposures and continued exposures to legacy phased-out chemicals and their substitutes in buildings. These findings warrant further research on the role of chemicals in office buildings on worker health.

Optimization and validation of a two-step method for the determination of polybrominated diphenyl ethers in Croatian house dust samples

Microwave-assisted extraction was applied as a method for extraction of seven polybrominated diphenyl ether (PBDE) congeners (28, 47, 99, 100, 153, 154, and 183) from house dust samples. Optimization of MAE experimental conditions was achieved using a multivariate design approach, and the results indicated that only the choice of extraction solvent had a statistically significant influence on extraction efficiency. The extract purification step was also investigated in detail with a goal to achieve effective cleaning, with minor solvent consumption. As the final operating conditions, 20 min MAE extraction from 1 g of dust with 20 mL of n-hexane : acetone (1 : 1, v/v) at 80 °C and extract purification on an in-lab prepared column containing 2 g of neutral silica and 4 g of acidified silica, whereby the PBDEs were eluted from the column with 15 mL of n-hexane : dichloromethane (4 : 1, v/v), were selected. The extracts were analyzed on a dual GC-μECD system, and GC-MS/MS was used as a confirmatory method. The performance of the optimized method was validated by analyzing spiked dust samples and a standard reference material (NIST 2585 "Organic Contaminants in House Dust"). Congener specific PBDE recovery ranged from 76% to 90% for the spiked samples (with very good repeatability; RSD < 7%) and the measured mass concentrations of selected PBDEs were in excellent agreement with certified values for a standard reference material. The proposed method was successfully applied to the analysis of targeted PBDEs in house dust samples.

Preliminary results on polybrominated diphenyl ether contamination status in Croatian households and insights into children's exposure

Polybrominated diphenyl ether (PBDE) congeners were analyzed in house dust samples collected in Croatian households. ∑PBDEs ranged between 1.1 ng g^-1 dust and 17662.4 ng g^-1 dust with BDE-99 being the most dominant congener accounting for approximately 60 %. The estimated daily intake (EDI) for toddlers as the most vulnerable population group ranged from 0.003 to 55.04 and from 0.01 to 110.07 ng kg^-1 bw day^-1 in the central and worst case scenario, respectively. The EDI calculated for the dominant BDE-99 in the sample with the highest ∑PBDE was in the worst case scenario 68.99 ng kg^-1 bw day^-1, which was quite close to the reference dose of 100 ng kg^-1 bw day^-1.

Concentrations of organic contaminants in industrial and municipal bioresources recycled in agriculture in the UK

Many types of bioresource materials are beneficially recycled in agriculture for soil improvement and as alternative bedding materials for livestock, but they also potentially transfer contaminants into plant and animal foods. Representative types of industrial and municipal bioresources were selected to assess the extent of organic chemical contamination, including: (i) land applied materials: treated sewage sludge (biosolids), meat and bone meal ash (MBMA), poultry litter ash (PLA), paper sludge ash (PSA) and compost-like-output (CLO), and (ii) bedding materials: recycled waste wood (RWW), dried paper sludge (DPS), paper sludge ash (PSA) and shredded cardboard. The materials generally contained lower concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) relative to earlier reports, indicating the decline in environmental emissions of these established contaminants. However, concentrations of polycyclic aromatic hydrocarbons (PAHs) remain elevated in biosolids samples from urban catchments. Polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) were present in larger amounts in biosolids and CLO compared to their chlorinated counterparts and hence are of potentially greater significance in contemporary materials. The presence of non-ortho-polychlorinated biphenyls (PCBs) in DPS was probably due to non-legacy sources of PCBs in paper production. Flame retardent chemicals were one of the most significant and extensive groups of contaminants found in the bioresource materials. Decabromodiphenylether (deca-BDE) was the most abundant polybrominated diphenyl ether (PBDE) and may explain the formation and high concentrations of PBDD/Fs detected. Emerging flame retardant compounds, including: decabromodiphenylethane (DBDPE) and organophosphate flame retardants (OPFRs), were also detected in several of the materials. The profile of perfluoroalkyl substances (PFAS) depended on the type of waste category; perfluoroundecanoic acid (PFUnDA) was the most significant PFAS for DPS, whereas perfluorooctane sulfonate (PFOS) was dominant in biosolids and CLO. The concentrations of polychlorinated alkanes (PCAs) and di-2-ethylhexyl phthalate (DEHP) were generally much larger than the other contaminants measured, indicating that there are major anthropogenic sources of these potentially hazardous chemicals entering the environment. The study results suggest that continued vigilance is required to control emissions and sources of these contaminants to support the beneficial use of secondary bioresource materials.

Household low pile carpet usage was associated with increased serum PFAS concentrations in 2005-2006

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the serum of the general US population. Food, drinking water, consumer products, dust, and air have been assessed as PFAS exposure sources for humans. The effects of various types of carpeting on serum PFAS concentrations have been less studied, despite the known use of PFAS in stain-resistant carpet treatments.

OBJECTIVE

This study aimed to examine the associations between serum PFAS concentrations and type of residential flooring among the general US population aged 12 years and older using the 2005-2006 National Health and Nutrition Examination Survey (NHANES).

METHODS

We used multiple linear regressions adjusted for complex survey design and relevant covariates to analyze the relations between serum PFAS concentrations and type of floor covering (smooth surface, low pile carpet, medium to high pile carpet, and combination of carpet and smooth surface), as well as other potential exposure factors. We used multiple imputation to address missing values.

RESULTS

We found significantly higher serum concentrations of perfluorohexane sulfonic acid (PFHxS) and 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (MeFOSAA) in US residents residing in homes with low pile carpeting compared with those residing in homes with smooth surface. We concluded that among US residents aged 12 years and older residing in homes with low pile carpeting in the home in 2005-2006, on average 24% and 19% of the PFHxS and MeFOSAA body burdens, respectively, could be attributed to carpeting. We found associations between other types of floor covering (medium to high pile carpet, combination of carpet and smooth surface) and some PFAS concentrations compared with the smooth surface, but these results were less consistent and generally not statistically significant. Additionally, a group Wald Chi-squared test showed a significant result for PFOS, indicating different contributions of various types of flooring to PFOS serum concentration.

SIGNIFICANCE

Our results are representative of the general US population at the time of the survey, and potentially informative regarding ongoing PFAS exposure from a variety of sources including carpeting.

Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food

The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.

Emerging and legacy per- and polyfluoroalkyl substances in house dust from South China: Contamination status and human exposure assessment

Our study investigated a large variety of per- and polyfluoroalkyl substances (PFASs) in house dust collected from Guangzhou, South China during 2015-2018. The perfluorobutane sulfonic acid (PFBS) exhibited the highest median concentration (17.6 ng/g), followed by linear perfluorooctanoic acid (L-PFOA; 4.8 ng/g), linear perfluorooctane sulfonic acid (L-PFOS; 4.2 ng/g), 6:2 fluorotelomer phosphate diester (6:2 diPAP; 3.4 ng/g), perfluorodecanoic acid (PFDA; 1.2 ng/g) and perfluoroundecanoic acid (PFUdA; 1.2 ng/g), and 6:2 chlorinated perfluoroalkyl ether sulfonic acid (6:2 Cl-PFESA; 1.1 ng/g). Total concentrations of PFASs (median: 53 ng/g) were generally within the 25-50 percentile of the concentration range reported in global studies. However, our samples exhibited composition profiles different from those reported in many other regions. Analysis based on this and previous studies revealed that the compositions in house dust from East Asia, North America, and Europe exhibit a region-specific pattern. This may indicate region-specific market demands, application patterns, as well as associated human exposure risks. Exploration of dwelling characterizations suggested that renovation history appeared to be a significant factor influencing PFAS concentrations in house dust, although other factors may exist and play a role. Estimation of daily intakes via dust ingestion and dermal contact indicates low exposure risks from these two pathways. However, the PFAS chemical-specific biological effects, possible mixture effects, as well as additional exposure pathways, imply that the risk from indoor PFAS exposure should not be overlooked.

Human Health Risk Assessment by Dietary Intake and Spatial Distribution Pattern of Polybrominated Diphenyl Ethers and Dechloran Plus from Selected Cities of Pakistan

A class of intractable bio accumulative halogenated compounds polybrominated diphenyl ethers (PBDEs) was studied. Specifically, PBDEs and dechloran plus (DP) contamination in wheat and the assaulted environment—agricultural soil and dust—from metropolitan cities of Pakistan was the focus. The exposure of brominated flame retardants (BFRs) to humans, their probable toxicological impact on health, source apportionment, and the spatial tendency of BFRs were studied. Chromatographic analysis was performed, and concentrations (ng g⁻¹) of ΣPBDE and ΣDP in soil, dust, and cereal crops were estimated in a range from 0.63 to 31.70 n.d. to 6.32 and n.d. to 3.47, respectively, and 0.11 to 7.05, n.d. to 4.56 and 0.05 to 4.95, respectively. Data analysis of source apportionment reflected that the existence of solid and e-waste sites, long-range transport, urban and industrial fraction can be the potential source of PBDE and DP pollution. Moreover, potential hazardous risks to human health across the study area via the dietary intake of cereal foods were deemed trifling, and were gauged on the basis of existing toxicological data.

Perfluoroalkyl acids in pregnant women from Nunavik (Quebec, Canada): Trends in exposure and associations with country foods consumption

BACKGROUND

Perfluoroalkyl acids (PFAAs) are persistent and ubiquitous environmental contaminants that potentially disrupt endocrine system functions. While some PFAAs (perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA)) are regulated, currently used fluorotelomer alcohols (FTOHs) can be transported to the Arctic and are degraded in a number of PFAAs which biomagnify in Arctic wildlife (e.g. perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA)).

OBJECTIVES

From 2004 to 2017, 279 pregnant Inuit women were recruited as part of biomonitoring projects in Nunavik. Our goal was to evaluate: (i) time-trends in plasma/serum PFAAs levels in pregnant Nunavimmiut women between 2004 and 2017; (ii) compare plasma/serum PFAAs levels in Nunavimmiut women in 2016-2017 to those measured in women of childbearing age in the Canadian Health Measure Survey (CHMS); and (iii) evaluate the associations of PFAAs levels with the consumption of country foods and pregnancy and maternal characteristics during pregnancy in the 97 participants recruited in 2016-2017.

METHODS

Individual blood sample were collected for serum or plasma PFAAs (PFOS, PFOA, pentafluorobenzoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorobutanesulfonic acid (PFBS), perfluorohexane-1-sulfonic acid (PFHxS), PFNA, PFDA, PFUdA) analyses. Socio-demographic data, pregnancy and maternal characteristics and country foods consumption were documented using a questionnaire. Omega-3 and -6 polyunsaturated fatty acids (PUFA) were measured in red blood cell membranes and their ratio used as a biomarker of marine country foods consumption. Time-trends in PFAAs levels were evaluated using ANCOVA models adjusted for relevant co-variables. Serum/plasma levels of PFAAs in the 97 pregnant women aged 16 to 40 years old and recruited in 2016-2017 were compared to those measured in women aged 18 to 40 years old from the CHMS cycle 5 (2016-2017) using the geometric means (GM) and 95% confidence intervals (95% CI). Multivariate regression analyses were performed to examine associations between concentrations of PFAAs and country foods consumption data.

RESULTS

Statistically-significant downward time trends were noted for concentrations of PFOS, PFOA and PFHxS in pregnant Nunavik women between 2004 and 2017. Conversely, between 2011 and 2016-2017, PFNA, PFDA and PFUdA maternal serum levels increased by 19, 13 and 21% respectively. Among participants in 2016-2017, mean concentrations for PFNA (GM: 2.4 μg/L), PFDA (0.53 μg/L) and PFUdA (0.61 μg/L) were higher than those measured in women aged 18-40 years old in the Cycle 5 (2016-2017) of the CHMS. PFOA (0.53 μg/L) and PFHxS (0.26 μg/L) were lower than in CHMS, whereas PFBA, PFHxA and PFBS were not detected in 2016-2017. Ratios of serum/plasma levels of PFNA/PFOA, PFNA/PFOS, PFNA/PFHxS and PFUdA/PFDA were significantly higher in the 97 pregnant women from Nunavik recruited in 2016-2017 compared to CHMS, highlighting their distinct exposure profile. In multivariate models, PFHxS, PFOS, PFNA, PFDA and PFUdA levels in 2016-2017 were strongly associated with the omega-3/omega-6 PUFA ratio, indicating a positive association between marine country foods consumption and higher exposure to PFAAs.

CONCLUSIONS

The exposure of pregnant women to long-chain PFAAs (PFNA, PFDA and PFUdA) increased from 2004 to 2017 in Nunavik. Associations noted between PFAAs levels and the omega-3/omega-6 ratio highlights the importance of implementing additional strict regulations on PFAAs and their precursors to protect the high nutritional quality and cultural importance of country foods in Nunavik.

Per- and Polyfluoroalkyl Substances in Dust Collected from Residential Homes and Fire Stations in North America

Over the past few years, human exposure to per- and polyfluoroalkyl substances (PFAS) has garnered increased attention. Research has focused on PFAS exposure via drinking water and diet, and fewer studies have focused on exposure in the indoor environment. To support more research on the latter exposure pathway, we conducted a study to evaluate PFAS in indoor dust. Dust samples from 184 homes in North Carolina and 49 fire stations across the United States and Canada were collected and analyzed for a suite of PFAS using liquid and gas chromatography-mass spectrometry. Fluorotelomer alcohols (FTOHs) and di-polyfluoroalkyl phosphoric acid esters (diPAPs) were the most prevalent PFAS in both fire station and house dust samples, with medians of approximately 100 ng/g dust or greater. Notably, perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate, perfluorononanoic acid, and 6:2 diPAP were significantly higher in dust from fire stations than from homes, and 8:2 FTOH was significantly higher in homes than in fire stations. Additionally, when comparing our results to earlier published values, we see that perfluoroalkyl acid levels in residential dust appear to decrease over time, particularly for PFOA and PFOS. These results highlight a need to better understand what factors contribute to PFAS levels in dust and to understand how much dust contributes to overall human PFAS exposure.

Perfluorinated compounds in the aquatic food chains of two subtropical estuaries

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous in the environment and remain in largely unknown concentrations and with unknown effects on the African continent. Here we aimed to assess the presence of 15 PFASs in different compartments of the aMatikulu and uMvoti estuaries and to examine potential risks for human health through the consumption of contaminated fish. This is the first known study to assess PFASs in South African estuaries. Thirteen out of the fifteen PFASs were detected in water, sediment and biota samples from both estuaries, with perfluorooctanoic acid (PFOA), detected in every sample. PFOA concentrations from uMvoti water samples were the highest recorded to date in South African waters. PFOA was found in high concentrations in all water samples with an average range between 171 and 258 ng/L in the aMatikulu and 711-788 ng/L in the uMvoti. Perfluorooctane sulfonate (PFOS) concentrations in fish tissue samples were significantly higher than other PFASs. PFOS concentrations in all fish species caught in the aMatikulu ranged between 0.09 and 2.25 ng/g wet weight (ww) in muscle tissue and 1.5-12.08 ng/g ww in liver tissue, while PFOA concentrations ranged between 0.08 and 0.67 ng/g ww in muscle tissue and 0.54-1.48 ng/g ww in liver tissue. Concentrations of PFASs were only measured in Oreochromis mossambicus from the uMvoti and contained PFOS concentrations ranging from 0.18 to 0.97 ng/g ww in muscle tissue and 7.29-27.96 ng/g ww in liver tissue. PFOA concentrations ranged between 0.12 and 0.58 ng/g ww in muscle tissue and 0.17-1.01 ng/g ww in liver tissue. PFAS concentrations in all fish sampled were below the calculated Minimum Risk Levels (MRLs) for safe human consumption.

Indoor polybrominated diphenyl ethers in urban China: An exposure and risk assessment based on settled dust from selected urban regions

In this study, measurements of seven typical polybrominated diphenyl ethers (PBDEs) in indoor settled dust were summarized in selected urban regions of China. BDE-209 was the most dominant congener in settled dust (1.4-101 μg/g), with a mean contribution of 95%. Indoor exposures to PBDEs were estimated via inhalation, dust ingestion, and dermal absorption. The average daily intake of ΣPBDE was 4.9 to 19.1 ng/day/kg for all the population groups, with >80% of the total exposures from dust ingestion. Exposures in commuting environments (contributing 60%-80% of the total exposures) were higher than those in other microenvironments. The means of hazard indexes ranged from 1.66 × 10^-3 to 5.26 × 10^-3, which were mainly as a result of exposure to BDE-209, BDE-47, and BDE-99. The average lifetime cancer risks were from 0.03 × 10^-9 to 2.37 × 10^-9, which indicated the acceptable health risks resulting from indoor PBDE exposure for the Chinese population. The present study could provide valuable information that could be helpful for decision-makers, analysts and researchers to develop, implement and evaluate the effectiveness of interventions for the reduction of exposures to semi-volatile organic compounds (SVOCs) for large population groups in China.

Indoor exposure to per- and polyfluoroalkyl substances (PFAS) in the childcare environment

Per- and polyfluoroalkyl substances (PFAS) are widely used in stain-resistant carpets, rugs, and upholstery, as well as in waxes and cleaners, and are potential contaminants in the childcare environment. However, limited knowledge exists on the occurrence of PFAS in indoor environments, apart from residential homes. Here, we determined the occurrence and distribution of 37 neutral and ionic PFAS, including perfluoroalkyl carboxylates (PFCAs) perfluoroalkyl sulfonates (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer sulfonates (FTSs), perfluorooctane sulfonamides and perfluorooctane sulfonamidoethanols (FOSAs/FOSEs), and fluorotelomer acrylates and fluorotelomer methacrylates (FTACs/FTMACs) in the childcare environment and estimated children's exposure through dust ingestion and dermal absorption. We analyzed dust and nap mats, a commonly used item in many childcares, from eight facilities located in the United States. Twenty-eight PFAS were detected in dust with total PFAS concentrations (ΣPFAS) ranging from 8.1 to 3,700 ng/g and were dominated by the two neutral PFAS groups: ΣFTOH (n.d. - 3,100 ng/g) and ΣFOSA/FOSE (n.d. - 380 ng/g). The ionic PFAS were detected at lower concentrations and were dominated by 6:2 FTS and 8:2 FTS (median 12 and 5.8 ng/g, respectively). ΣPFAS concentrations in mats (1.6-600 ng/g) were generally an order of magnitude lower than in dust and were dominated by ΣFOSA/FOSE concentrations (n.d. - 220 ng/g). Daily intake of neutral PFAS in the childcare environment via dust ingestion was estimated at 0.20 ng/kg bw/day and accounted for 75% of the ΣPFAS intake. This higher exposure to neutral PFAS is concerning considering that many neutral PFAS are the precursors of toxic ionic PFAS, such as PFOA.

Perfluoroalkyl Substances in Drinking Water, Indoor Air and Dust from Ireland: Implications for Human Exposure

Perfluoroalkyl substances (PFASs) were measured in air and dust from cars, homes, offices, and school classrooms in Ireland, along with drinking water from homes and offices. Perfluorooctanoic acid (PFOA) dominated air and drinking water, while perfluorobutane sulfonate (PFBS) dominated dust. This is the first report of PFOA, perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), PFBS, and perfluorononanoic acid (PFNA) in air inside cars and school classrooms. PFOS concentrations in classroom air exceeded significantly (p ≤ 0.05) those in homes. Atmospheric concentrations of PFOA, PFNA, and methyl perfluorooctane sulfonamido ethanol (MeFOSE) (p ≤ 0.05) were significantly higher in cars containing child car seats than in cars without. PFOS, PFOA, PFBS, and PFHxS were all detected frequently in drinking water, but concentrations of PFASs were low, and although ΣPFASs were 64 ng/L in one bottled water sample, this fell below a Swedish Action Level of 90 ng ΣPFASs/L. The Irish population's exposure to PFOS and PFOA via non-dietary sources is well below estimates of dietary exposure elsewhere in Europe. Moreover, even under a high-end exposure scenario, it falls below the European Food Safety Authority's (EFSA) provisional tolerable weekly intakes for PFOS and PFOA.

Perfluoroalkyl substances (PFASs) in air-conditioner filter dust of indoor microenvironments in Greece: Implications for exposure

The occurrence of perfluoroalkyl substances (PFASs) was for the first time investigated in various working microenvironments (internet cafes, electronics shops, coffee shops, restaurants, etc.) in Thessaloniki, Greece, using the dust trapped by central air conditioner (A/C) filters. Perfluorooctane sulfonic acid (PFOS) was found in the range from 16 to 227 ng g^-1, however it was detectable in only 30% of samples. On the contrary, perfluorohexanoic acid (PFHxA) was found in 85% of samples in the range from 3.6 to 72.5 ng g^-1, while 90-95% of samples exhibited perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDcA) and perfluorododecanoic acid (PFDoDA) in the range from 10-653 ng g^-1, 3.2-7.4 ng g^-1 and 3.8-13.1 ng g^-1, respectively. The PFAS profile varied largely among the different microenvironment categories suggesting different sources. Estimated daily intakes through dust ingestion were calculated.

Occurrence and human exposure assessment of perfluorinated substances in house dust from three European countries

65 house dust samples from three European countries (Belgium, Italy and Spain) were evaluated for the presence of 20 polyflouroalkyl substances (PFASs) including perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acid (PFCAs) and perfluoroalkane sulfonamides (PFOSAs). The three countries presented similar PFAS levels ranging from 3.13 to 155 ng/g (12.9 ng/g; median), but in all cases PFCAs concentrations (6.92, 15.2 and 8.68 ng/g; median for Belgium, Italy and Spain) were higher than those obtained for PFSAs (2.30, 1.76 and 2.68 ng/g). Interestingly, in comparison to previously published data exhibited an increase in perfluorobutanesulfonate (PFBS) concentrations in Belgian house dust. On the other hand, levels of perfluorooctanesulfonate (PFOS) decreased in Spanish case. Data were examined for relationships between PFAS house dust levels, building and outdoor surrounding characteristics and occupant habits. Main findings revealed a positive association between PFOS concentrations and the building edification age, which could highlight a decrease in the use of this chemical in Europe. Similarly, perfluorohexanesulfonate (PFHxS) levels correlated with the percentage of the floor covered by textiles. Homes located in industrial sites showed higher PFCA levels compared to urban or agricultural locations, revealing the industrial processes as a potential source of these chemicals in Europe. Data obtained were used to perform human exposure assessment for dust intake via oral ingestion. Estimated daily intakes, calculated for toddlers and adults at median and worst case scenarios, were below oral Reference Dose (RfD) and tolerable daily intakes (TDI). However, in perfluorooctanoic acid (PFOA) case, dust ingestion significance to total dietary exposure reached values of 51% for toddlers in the worst case scenario.

Occurrence of two novel triazine-based flame retardants in an E-waste recycling area in South China: Implication for human exposure

The recent increase in the use of alternative flame retardants (FRs) in consumer products has led to emerging contaminants in the environment. Identification of novel FRs is urgently needed because the potential threat posed by these chemicals has provoked considerable attention, but the details of the threat are not yet widely understood. In this study, two novel triazine-based FRs, tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO) and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ), were identified in dust samples from an e-waste recycling area in China. Two legacy FRs, namely, tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD), were also analyzed for comparison. The mean level of TDBP-TAZTO in the e-waste dust samples was found to be much higher (2060 ng g^-1) than that of HBCDD (526 ng g^-1), while the mean level of TTBP-TAZ in residential dust samples was moderately higher (119 ng g^-1) than that of HBCDD (35.7 ng g^-1). A comparison of the TDBP-TAZTO and TTBP-TAZ concentrations with those of other alternative and legacy FRs indicated that TDBP-TAZTO is a major FR that is currently used in China. The estimated daily intake of TDBP-TAZTO via dust ingestion for occupational workers was much higher than that of HBCDD and was also much higher than for local adults and children. Exposure to TDBP-TAZTO poses a potentially high risk to the health of the local population, especially for the occupational workers, when the multicomponent chemical 'cocktail' effects are taken into account. More investigations on the environmental behaviors and risk factors of TDBP-TAZTO and TTBP-TAZ in various environmental matrices, as well as their toxicological effects, should be performed in the future.

Destruction behavior of short- and medium-chain chlorinated paraffins in solid waste at a pilot-scale incinerator

Incineration experiments with solid wastes containing approximately 3% (w/w) short-chain chlorinated paraffins (SCCPs) that have recently been listed as persistent organic pollutants (POPs) and medium-chain chlorinated paraffins (MCCPs) were conducted using a pilot-scale incinerator to investigate the efficiency of their destruction as well as the unintentional formation of POPs and their destruction behaviors during controlled incineration. A series of experiments demonstrated that SCCPs and MCCPs in solid wastes were progressively destroyed and removed during rotary kiln combustion and downstream flue gas treatments. Destruction efficiencies of SCCPs and MCCPs exceeding 99.9999% were confirmed. SCCPs in bottom and fly ash samples were present at levels below their quantification limits (0.021 and 0.31 mg/kg), and MCCPs in the bottom and fly ash samples were likewise present at concentrations below their quantification limits (0.034 and 0.50 mg/kg). Total concentrations of toxicity equivalency quantities (TEQs) for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in emission gas samples collected at the bag filter exit and final exit were 0.083-0.30 and 8.7 × 10^-7 to 1.3 × 10^-4 ng-TEQ/m³N, respectively, and those in bottom and fly ash samples were 0.12-0.47 and 9.0 × 10^-3 to 0.14 ng-TEQ/g, respectively. The results obtained in this study suggest that controlled incineration of solid wastes under the current regulations for incinerators in Japan and the countries with regulations and monitoring to minimize emissions of PCDDs/DFs and dl-PCBs is one of the best available technologies for the environmentally sound management of wastes containing SCCPs and MCCPs.

Per- and polyfluorinated compounds in saleswomen's urine linked to indoor dust in clothing shops

This study aims to investigate the characteristics of typical per- and polyfluorinated compounds (PFCs) in indoor dust from clothing shops and urine sampled from saleswomen. A total of 58 indoor dust samples and 73 urine samples from saleswomen were collected from clothing shops in Shanghai, China. All samples were analyzed for PFCs using high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC-MS/MS). The mean PFC concentrations in indoor dust ranged from 0.42 (PFDA) to 5.04 ng g^-1 (PFDoA). PFDoA and PFHxS were the most prominent PFCs, with median concentrations of 2.95 ng g^-1 and 1.49 ng g^-1, respectively. The median PFC concentrations in urine ranged from 10.15 (PFDS) to 666.1 ng l^-1 (PFOA) and PFOA was the most abundant chemical with concentrations ranging from 207 to 907 ng l^-1. A significant positive correlation was obtained between long-chain PFCs in dust and in urine (p < 0.01). Daily intake values of PFCs via dust ingestion were also calculated, and even under high-end exposure scenarios, the intake of PFOA (36.5 pg day^-1) and PFOS (56.7 pg day^-1) were well within the tolerable daily intake values. These results are important to both characterize PFC levels and estimate the saleswomen's exposure to PFCs from indoor dust.

Does soil track-in contribute to house dust concentrations of perfluoroalkyl acids (PFAAs) in areas affected by soil or water contamination?

The Minnesota Department of Health measured levels of perfluoroalkyl acids (PFAAs) in house dust at homes in communities impacted by PFAA-contaminated soil and drinking water to determine whether PFAAs in soil outside the home are associated with concentrations in dust. House dust samples from both interior living spaces and entryways to the yard were collected and analyzed separately based on the presumption that PFAAs in entryway dust may better reflect "track-in" of PFAAs into the home from contaminated soil or lawns irrigated with contaminated water. PFAA detections and concentrations in living rooms were significantly higher compared to entryways; and concentrations in both sampling locations were higher than corresponding soil concentrations, suggesting that interior sources were the main contributors to PFAAs in house dust. PFAA dust concentrations in entryways were significantly associated with living room dust levels for all analytes except PFBA. Relationships between entryway dust and soil were only seen for one PFAA (PFOA). However, median concentrations of PFOA in entryway and living room dust were 35 and 70 times higher (respectively) than in soil, which highlights the lack of importance of PFAA soil track-in as a contributor to dust concentration in this setting. Due to the small sample size, larger scale studies are needed to further assess the potential for migration of PFAA contaminated soil to indoor dust.

Organohalogenated Flame Retardants and Organophosphate Esters in Office Air and Dust from Sweden

A wide range of organohalogenated flame retardants (HFRs) and organophosphate esters (OPEs) were measured in air and floor dust from 10 offices in Stockholm, Sweden. Concentrations of ∑18 emerging HFRs, ∑21 legacy HFRs and ∑11 OPEs from the offices were found to be 420, 510, and 1600000 ng/g, respectively, in floor dust and 400, 15, and 160 000 pg/m³ respectively in active air samples. All targeted compounds were detected in dust except 2,3,5,6-tetrabromo- p-xylene (pTBX) indicating widespread application of a broad range of FRs in the Swedish offices while only 54% of targeted compounds were detected in indoor air. Estimated ∑OPE exposure in Swedish offices is 3-4 orders of magnitude higher than for ∑emerging HFRs and ∑legacy HFRs via all three different exposure routes in our study. Adult's estimated intakes of emerging and legacy HFRs and OPEs from office air and dust during working hours (30% of a day) are some orders of magnitude lower than the corresponding reference doses (RfD). However, in worst case exposure scenarios (maximum concentrations and high dust intake), the intake of tris(2-butoxyethyl) phosphate (TBOEP) was one-third of its RfD, which may be of potential concern if exposure is as high in other microenvironments.

Accumulation of perfluorinated alkyl substances (PFAS) in agricultural plants: A review

PFASs are a class of compounds that include perfluoroalkyl and polyfluoroalkyl substances, some of the most persistent pollutants still allowed - or only partially restricted - in several product fabrications and industrial applications worldwide. PFASs have been shown to interact with blood proteins and are suspected of causing a number of pathological responses, including cancer. Given this threat to living organisms, we carried out a broad review of possible sources of PFASs and their potential accumulation in agricultural plants, from where they can transfer to humans through the food chain. Analysis of the literature indicates a direct correlation between PFAS concentrations in soil and bioaccumulation in plants. Furthermore, plant uptake largely changes with chain length, functional group, plant species and organ. Low accumulations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have been found in peeled potatoes and cereal seeds, while short-chain compounds can accumulate at high levels in leafy vegetables and fruits. Significant variations in PFAS buildup in plants according to soil amendment are also found, suggesting a particular interaction with soil organic matter. Here, we identify a series of challenges that PFASs pose to the development of a safe agriculture for future generations.

Polybrominated diphenyl ethers and novel brominated flame retardants in indoor dust of different microenvironments in Beijing, China

The occurrence levels of eight polybrominated diphenyl ethers (PBDEs) and four novel brominated flame retardants (NBFRs) were determined and compared in indoor dust from different microenvironments (21 homes, 23 offices and 16 day care centers) in Beijing, China. Concentrations of ∑₈PBDEs in dust were 430-17,000 ng/g, 690-8600 ng/g, and 90-2300 ng/g for homes, offices, and day care centers, respectively, and were dominated by BDE-209. Concentrations of ∑₄NBFRs ranged from 310 to 17,000 ng/g, 300 to 4300 ng/g, and not detected to 500 ng/g for homes, offices, and day care centers, respectively, and were dominated by bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEH-TEBP) and decabromodiphenylethane (DBDPE) across microenvironments. The results showed an increasing detection and elevated concentration of NBFRs (especially BEH-TEBP), indicating that monitoring of NBFRs in dust samples should be of concern in future studies. A notable finding was that the BFR concentrations in dust samples from day care centers were generally one order of magnitude lower than those from homes and offices in the present study. This implies that previous estimates of toddler exposure via dust ingestion on data from homes may be overestimated. Concentrations of BDE-209 and ∑₈PBDEs were found to be significantly higher in elevated surface dust than floor dust from day care centers. The estimates of daily intakes of BFRs via dust ingestion for Chinese adults and toddlers using Monte Carlo analysis were 2-5 orders of magnitude lower than the corresponding reference daily intakes.

Fluorotelomer alcohols (FTOHs), brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs) and cyclic volatile methylsiloxanes (cVMSs) in indoor air from occupational and home environments

Indoor air samples were collected from private homes and various occupational indoor environments using passive air sampler and analysed for fluorotelomer alcohols (FTOHs), brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs) and cyclic volatile methyl siloxanes (cVMSs). The aim was to investigate their occurrence in indoor air, factors that may affect their presence and human daily exposure dose (DED) via inhalation. In general, levels of cVMSs were 3-4 orders of magnitude greater than the other compound classes. OPFRs concentration was found significantly higher than BFRs in indoor air. The most abundant compounds in each chemical class were 8:2 FTOH, 2,4,6-TBP, TNBP and TCEP and decamethylcyclopentasiloxane (D5). Home samples contained higher level of FTOHs, BFRs and cVMSs than occupational environments, whereas concentration of OPFRs in office samples were higher. BFRs concentrations were significantly correlated with building age and with the number of electronic/electrical devices at the sampling sites. Moreover, significantly lower levels of FTOHs and cVMSs were observed in rooms with forced-ventilation system. Estimated DED via inhalation was significantly higher at home than in office and the total DED was on average 3-5 orders of magnitude lower than the reference value.

Perfluoroalkyl acids and their precursors in floor dust of children's bedrooms - Implications for indoor exposure

We analysed floor dust samples from 65 children's bedrooms in Finland collected in 2014/2015 for 62 different per- and polyfluoroalkyl substances (PFASs) with a simple and highly efficient method. Validation results from the analysis of standard reference material (SRM) 2585 were in good agreement with literature data, while 24 PFASs were quantified for the first time. In the dust samples from children's bedrooms, five perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctane sulfonic acid (PFOS) were detected in more than half of the samples with the highest median concentration of 5.26 ng/g for perfluorooctanoic acid (PFOA). However, the dust samples were dominated by polyfluoroalkyl phosphoric acid esters (PAPs) and fluorotelomer alcohols (FTOHs) (highest medians: 53.9 ng/g for 6:2 diPAP and 45.7 ng/g for 8:2 FTOH). Several significant and strong correlations (up to ρ = 0.95) were found among different PFASs in dust as well as between PFASs in dust and air samples (previously published) from the same rooms. The logarithm of dust to air concentrations (log K_dust/air) plotted against the logarithm of the octanol-air partition coefficient (log K_oa) resulted in a significant linear regression line with R² > 0.88. Higher dust levels of PFOS were detected in rooms with plastic flooring material in comparison to wood (p < 0.05). Total estimated daily intakes via dust (EDI_dust) and air (EDI_air) of perfluoroalkyl acids (PFAA), including biotransformation of precursors to PFAAs, were calculated for 10.5-year-old children. The total EDI_dust for PFOA and PFOS were estimated to be 0.007 ng/kg bw/day and 0.006 ng/kg bw/day, respectively, in an intermediate exposure scenario. The sum of the total EDIs for all PFAAs was slightly higher for dust than air (0.027 and 0.019 ng/kg bw/day). Precursor biotransformation was generally important for total PFOS intake, while for the PFCAs, FTOH biotransformation was estimated to be important for air, but not for dust exposure.

Challenges in the Analysis of Novel Flame Retardants in Indoor Dust: Results of the INTERFLAB 2 Interlaboratory Evaluation

The Interlaboratory Study of Novel Flame Retardants (INTERFLAB 2) was conducted by 20 laboratories in 12 countries to test the precision and accuracy of the analysis of 24 "novel" flame retardants (NFRs). Laboratories analyzed NFRs in injection-ready test mixtures, in extracts of residential dust, and in residential dust to evaluate the influence of dust handling and extraction. For test mixtures, mean reported concentrations of PBT, PBEB, EH-TBB, TBBPA, TBDP-TAZTO, TBOEP, α-TBCO, β-DBE-DBCH, and total HBCDD differed by >25% relative to reference values. Coefficients of variation were higher in dusts/dust extracts than in test mixtures. Concentrations among laboratories ranged over 3-4 orders of magnitude for HBB, TBP-DBPE, TBP-AE, and TDCIPP in dust extracts and dusts. Most laboratories produced repeatable dust concentrations, but differences reported in the literature among laboratories of <70% could be due to analytical variability, and the attribution of such differences to other causes should be made with caution. Most variations in accuracy and precision were introduced by matrix effects and/or sample processing, rather than instrumental analysis. We recommend recovery correction to improve accuracy. There is a need to improve analytical methods and to validate methods on complex matrices such as standard reference materials for dust or spiked matrices.

A review of semi-volatile organic compounds (SVOCs) in the indoor environment: occurrence in consumer products, indoor air and dust

As many people spend a large part of their life indoors, the quality of the indoor environment is important. Data on contaminants such as flame retardants, pesticides and plasticizers are available for indoor air and dust but are scarce for consumer products such as computers, televisions, furniture, carpets, etc. This review presents information on semi-volatile organic compounds (SVOCs) in consumer products in an attempt to link the information available for chemicals in indoor air and dust with their indoor sources. A number of 256 papers were selected and divided among SVOCs found in consumer products (n = 57), indoor dust (n = 104) and air (n = 95). Concentrations of SVOCs in consumer products, indoor dust and air are reported (e.g. PFASs max: 13.9 μg/g in textiles, 5.8 μg/kg in building materials, 121 ng/g in house dust and 6.4 ng/m³ in indoor air). Most of the studies show common aims, such as human exposure and risk assessment. The main micro-environments investigated (houses, offices and schools) reflect the relevance of indoor air quality. Most of the studies show a lack of data on concentrations of chemicals in consumer goods and often only the presence of chemicals is reported. At the moment this is the largest obstacle linking chemicals in products to chemicals detected in indoor air and dust.

Associations between PBDEs exposure from house dust and human semen quality at an e-waste areas in South China-A pilot study

Previous studies have confirmed that house dust is one of the main sources of polybrominated diphenyl ethers (PBDEs) exposure, and also indicated that PBDEs might affect human semen quality. The aim of this study was to explore the association between PBDEs concentration in house dust and the semen quality of male resident. Results showed that the semen qualities of the residents living around the e-waste dismantling workshops for a long time (3-17years) at the e-waste areas in South China significantly decreased, and the DNA damage of sperms were aggravated. The adjusted correlation analysed by multiple linear regression model showed that the sperm concentration and count both had negative correlation with BDE47 level in semen (β = -0.295, 95%CI: -0.553∼-0.036; β = -0.400, 95%CI: -0.708∼-0.092, respectively). In addition, the sperm progressive motility [(A+B)%] and sperm viability both had negative correlation with BDE100 level in dust (β = -0.360, 95%CI: -0.680∼-0.040; β = -0.114, 95% CI: -0.203∼-0.025, respectively). And there were significant linear positive correlation between PBDE congener (e.g. BDE28, 47, 153) concentrations in dust and in paired semen samples (r_s = 0.367-0.547, p < 0.05). This study suggested that exposure to PBDEs from house dust might have adverse effects on human semen quality. But the results need to be confirmed in further studies with a large-scale sampling, and find out more direct and convincing evidence.

Legacy and novel brominated flame retardants in indoor dust from Beijing, China: Occurrence, human exposure assessment and evidence for PBDEs replacement

Levels of legacy brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), hexabromocyclododecane isomers (HBCDs) and polybrominated diphenyl ethers (PBDEs), and six currently used novel BFRs were determined in house dust and office dust collected from a community in Beijing, China. This is the first study where the three kinds of legacy BFRs and novel BFRs were all measured in dust samples from China. HPLC-MS/MS was used for the detection of TBBPA and HBCDs, and the other BFRs were tested on a GC-NCI/MS. Decabromodiphenyl ethane (DBDPE), PBDEs, HBCD and TBBPA were found to be the main BFRs in the dust samples, with median levels of 709, 241, 199 and 26.7ng/g dust, respectively. Due to the high density of electronic equipment used in offices, levels of BFRs in office dust were found to be higher than those in house dust. DBDPE, as a replacement of PBDEs, was the predominant BFR, and the median level of DBDPE was not only several orders of magnitude higher than that of other novel BFRs but also 3 to 27 times higher than that of the three legacy BFRs, indicating that the consumption pattern of BFRs in the Chinese market has shifted from PBDEs to PBDE alternatives. Median estimated daily intakes (EDIs) of BFRs through dust ingestion for adults (>20years) and toddlers (<2years) were in the range of 2.8×10^-5-0.201ng/kg body weight (bw)/day and 5.7×10^-4-2.52ng/kg bw/day, respectively. The body burden of BFRs for toddlers was far higher than that for adults; however, a comparison between EDIs and threshold values suggested that daily intakes of BFRs for both adults and toddlers were unlikely to raise significant health concerns.

PFCA uptake and translocation in dominant wheat species (Triticum aestivum L.)

The comparative uptake of four perfluorinated carboxylic acids (PFCAs) by wheat (Triticum aestivum L.) grown in nutrient solution was investigated. Wheat is the main food crop in northern China and may become a potential pathway of human exposure to these PFCAs. The uptake of four PFCAs from water at a fixed concentration (1 μg/mL) increased over time, approaching a steady state, and except for the short-chain perfluorobutanoic acid, most of the total mass of each of the PFCAs taken up by wheat was found to be at the root. The root concentration factor (RCF) and shoot/root concentration factor (SRCF) were calculated, and with the increase in carbon chain length, the RCFs increased but SRCFs decreased, which indicated that long-chain PFCAs had stronger root uptake and weaker translocation capacities than short-chain PFCAs. In addition, pH could obviously impact the uptake of four PFCAs in the roots and shoots of wheat, and the highest concentrations were found at pH = 7 when the pH increased from 4 to 10.