Levels Of Perfluoroalkyl Acids Research Articles

Atmospheric diffusion of perfluoroalkyl acids emitted from fluorochemical industry and its associated health risks

The fluorochemical industry is an important emission source of atmospheric perfluoroalkyl acids (PFAAs). In this study, air samples were collected through active high-volume air samplers coupled with Tissuquartz™ filters around a fluorochemical manufacturer, and analyzed for PFAAs levels. Perfluorooctanoic acid (PFOA) was dominant with concentrations as high as 9730 pg/m3, followed by short chain perfluoroalkyl carboxylic acids (PFCAs). The PFAAs in the air were compared to those measured in outdoor dust and rain collected in the same area. Short chain PFCAs had a greater distribution in air, while PFOA was more distributed in dust and rain. With increasing concentrations, a significant decreasing trend for PFOA was observed in rain (P < 0.05). The estimated daily intake (EDI) of PFOA via indoor air inhalation by five age groups were calculated in two scenarios, and compared to the strictest tolerable daily intake (TDI) of PFOA (≤0.63 ng/kg bw/day). Potential health risk occurred in the best-case scenario, while the EDI from the worst-case scenario was comparable to that via indoor dust ingestion, indicating a notable health risk. This suggests that in terms of PFOA exposure and health risks, air inhalation may be as important as dust ingestion. These results highlight the impacts of PFAAs emissions from the fluorochemical industry to the atmosphere and ultimately, human health.

Perfluoroalkyl acids and their isomers, diabetes, anemia, and albuminuria: Variabilities with deteriorating kidney function

Data for US adults aged ≥20 years from National Health and Nutrition Examination Survey for the years 2003–2014 were analyzed to evaluate how adjusted (N = 8481) and unadjusted (N = 9080) levels of selected perfluoroalkyl acids (PFAA) vary across the different stages of glomerular function (GF) among those who did not have diabetes, anemia, or albuminuria as compared to those who had diabetes only, anemia only, and albuminuria only. PFAAs selected for analyses were: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). Irrespective of GF stage, there was no noticeable evidence to suggest that adjusted levels of PFAA for those with diabetes only are any lower than those with no diabetes, no anemia, and no albuminuria. Those who had anemia only were found to have lower adjusted levels of at least PFOA, PFOS, PFDA, and PFHxS than those who had no diabetes, no anemia, and no albuminuria. These results were seen in the presence (eGFR < 60 mL/min/1.73 m2) as well as the absence of chronic kidney disease. For GF-1 (eGFR > 90 mL/min/1.73 m2), GF-2 (60 ≤ eGFR ≤ 90 mL/min/1.73 m2), and GF-3B/4 (15 < eGFR ≤ 45 mL/min/1.73 m2), those who had albuminuria only had lower adjusted levels of PFOA, PFOS, and PFHxS than those who had no diabetes, no anemia, and no albuminuria. In general, adjusted levels of those who had albuminuria only were lower than those who had anemia only at GF-3 and more often than not at GF-1 and GF-2. Rise in adjusted levels of PFAA from GF-1 to GF-3A (45 < eGFR < 60 mL/min/1.73 m2) was faster for those with anemia only than any other comparison group for the total population and females.

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.

Within- and Among-Clutch Variation of Yolk Perfluoroalkyl Acids in a Seabird from the Northern Adriatic Sea.

Perfluoroalkyl substances (PFAS) are surface-active agents used in diverse industrial and commercial applications. They contaminate both freshwater and marine ecosystems, are highly persistent, and accumulate through trophic transfer. Seabirds are exposed to environmental contaminants due to their high trophic position in food webs and relatively long lifespan. We measured levels of 10 perfluoroalkyl acids (PFAAs) in egg yolks of yellow-legged gulls (Larus michahellis) breeding in the northern Adriatic Sea (Northeast Italy). We examined variations in PFAAs within clutches (between eggs of different laying order) and among clutches. Perfluorooctane sulfonate (PFOS) was the most abundant yolk PFAA (mean = 42.0 ng/g wet wt), followed by perfluorooctanoic acid (PFOA; 3.8 ng/g wet wt) and perfluorododecanoic acid (PFDoDa; 2.8 ng/g wet wt). The ∑PFAAs averaged 57.4 ng/g wet weight, ranging between 26.5 and 115.0 ng/g wet weight. The PFAA levels varied substantially among clutches (0.29-0.79 of the total variation), whereas the effects of laying order were considerably weaker (0.01-0.13). Egg-laying order effects were detected for ∑PFAAs, PFOS, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and PFDoDa, whereby the last-laid eggs exhibited lower PFAA concentrations than early-laid eggs. Our results indicate that seagulls from the northern Adriatic basin deposit measurable amounts of PFAAs in their eggs. The large among-clutches differences in PFAAs suggest that exposure of yellow-legged gull females to these compounds is highly variable. Environ Toxicol Chem 2021;40:744-753. © 2020 SETAC.

Are Feathers of a Songbird Model Species (The Great Tit, Parus major) Suitable for Monitoring Perfluoroalkyl Acids (PFAAs) in Blood Plasma?

Feathers have been shown to be useful in the biomonitoring of environmental contaminants, such as metals and persistent organic pollutants. However, little is known regarding the levels of perfluoroalkyl acids (PFAAs) in feathers and the applicability of these structures for the biomonitoring of these compounds. In the present study, we report the extent to which feathers are suitable for monitoring PFAA concentrations in the blood plasma of an insectivorous songbird model species, the great tit (Parus major), settled at and in the vicinity of a fluorochemical plant in Antwerp, Belgium. For most of the target analytes (out of the 15 investigated), the feather PFAA concentrations near the plant are the highest ever reported in free-living birds. As PFAA concentrations did not differ in the adjacent sites, no pollution gradient with distance from the plant was observed. In addition, the PFAA concentrations were not associated with the age and sex of the birds. Perfluorooctanoic acid (PFOA) concentrations were significantly higher in P. major feathers than in blood plasma, but for most other PFAAs, these differences were not observed. The concentrations of perfluorooctanesulfonate (PFOS) and PFOA in P. major feathers and plasma were significantly and positively correlated when combining data from all sites but often not at individual sites. This result was likely caused by lower sample sizes at the individual sites and the use of matrices that represent different time periods. Our results suggest that P. major feathers cannot be used to estimate PFOA and PFOS concentrations in blood plasma, except when there is a great deal of variation in pollutant concentrations among sites/individual birds. Both matrices represent different time frames, providing complementary information on environmental PFAA concentrations, as illustrated by the observation that more PFAA compounds could be detected in P. major feathers than in blood plasma.

Levels of Perfluoroalkyl Acids (PFAAs) in Human Serum, Hair and Nails in Guangdong Province, China: Implications for Exploring the Ideal Bio-Indicator.

The widespread human exposure to perfluoroalkyl acids (PFAAs) has led to increasing public concern. In this study, we present a comprehensive measurement of total fluorine (TF), extractable organic fluorine (EOF), identified organic fluorine (IOF, total concentration of identified PFAAs quantified as fluorine) and 11 target PFAAs in human serum (n = 60), hair (n = 49) and nails (n = 39) collected from non-occupation exposed volunteers in 10 cities of Guangdong Province, China. The results indicated that EOF was the major form of fluorine in serum, accounting for 70-80% of TF. The levels of IOF contributed less than 10% of EOF. Perfluorooctane sulfonic acid (PFOS) was found to be the dominant PFAA with mean concentration of 23ng·mL-1 in serum, 35ng·g-1 in hair and 33ng·g-1 in nail, respectively. Short-chain PFAAs (C ≤ 10) were the predominant PFAAs in three matrices. Levels of PFOS, perfluorohexane sulfonic acid (PFHxS), perfluoroundecanoic acid (PFUdA) and perfluorotridecanoic acid (PFTrDA) in males are significantly higher than those in females (p < 0.01). Significant positive correlations were observed between nail and serum for PFOS (p < 0.01), perfluorooctanoic acid (PFOA) (p < 0.05) and PFHxS (p < 0.01), suggesting that human nails, a noninvasive sample, are a promising bio-indicator for PFAA risk assessment.

Elevated bioaccumulation of PFAAs in Oryzias melastigma following the increase of salinity is associated with the up-regulated expression of PFAA-binding proteins

Perfluoroalkyl acids (PFAAs) are widely detected in the environment, especially in estuarine and coastal areas where fluctuation of salinity occurs. Salinity alteration affected the distribution of PFAAs and even the bioaccumulation in organisms. However, the inner mechanism is still unclear. In this study, the marine medaka (Oryzias melastigma), a euryhaline fish model, was exposed to four PFAAs congeners under three different salinities (0, 15 and 35 psu). Results showed that the bioaccumulation of PFAAs increased in fish as the water salinity increased. PFAAs with longer lengths of carbon‑fluorine bond showed higher bioaccumulation in the fish. Salinity did not alter the levels of PFAAs in water media, however, the uptake rate of PFAAs from gills did increase with the salinity. Further analysis of the mechanism showed that PFAA bound to branchial proteins as confirmed by fluorescence spectroscopy. Higher expressions of proteins binding to PFAAs including organic anion transporter 1 (OAT1) and fatty acid-binding protein (FABP) facilitated the uptake of PFAAs through gills in fish culturing under higher salinity. In all, our study showed that elevation of salinity can induce the expression of proteins binding to PFAAs in gills, thus facilitate the uptake of water PFAAs. Salinity fluctuation should be taken into consideration when assessing the chemical risk in the estuarine and coastal areas.

Associations between selected perfluoroalkyl acids in serum and hemoglobin in whole blood, a biomarker of anemia: Impact of deteriorating kidney function

Data (N = 11251) from National Health and Nutrition Examination Survey (NHANES) for 2003–2016 for US adults aged ≥20 years were stratified by gender and anemia and analyzed to evaluate the associations between the concentrations of whole blood hemoglobin (WBHGB) and selected perfluoroalkyl acids (PFAAs) in serum by stages of glomerular filtration (GF). Investigated PFAAs were perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). Females with whole blood hemoglobin concentrations <12 g/dL and males with whole blood hemoglobin concentrations <13 g/dL were classified as being anemic. Regression models with log10 transformed concentrations of whole blood hemoglobin as dependent variable and age, poverty income ratio, body mass index, serum cotinine, daily alcohol intake, survey year, and log10 concentrations of one of the PFAA as independent variables were fitted. For anemic females, association between WBHGB and PFAA concentrations were uniformly positive across worsening stages of renal failure and percent increases for 10% increases in PFAAs varied between 0.03% and 0.39%. For anemic males, association between WBHGB and PFAA concentrations were positive except at GF-3A (45 ≤ eGFR<60 mL/min/1.73 m2) and percent increases for 10% increases in PFAAs varied between 0.02% and 0.53%. Thus, more often than not, presence of positive associations between WBHGB and PFAA among anemics imply elevated levels of PFAA are associated with higher levels of WBHGB. Similar results were observed for non-anemic males and females, however strengths of associations between whole blood hemoglobin and PFAAs were several fold higher among anemic compared to non-anemic participants. Hemoglobin is consistently associated with serum PFAAs.

Spatial distribution of perfluoroalkyl acids (PFAAs) and their precursors and conversion of precursors in seawater deeply affected by a city in China.

Conversion of perfluoroalkyl acid (PFAA) precursors in the environment has been a hotspot research in recent years. This study firstly determined the spatial distribution of PFAAs and their precursors including 8:2 fluorotelomer unsaturated acid (8:2 FTUCA), perfluorooctane sulfoneamide (FOSA), and diperfluorooctane sulfonamido ethanol-based phosphate (di-SAmPAP), then investigated the conversion of the potential precursors in the seawater and sewage treatment plants (STPs) effluents. The results indicated that the target pollutants showed a typical concentration gradient from nearshore to offshore. And the obviously increased concentration of perfluorinated carboxylic acids (△[PFCAs]) after oxidation treatment can verify the existence of PFAA precursors in the seawater and STP effluents. The concentrations of PFCAs with carbon atom numbers 4-9 (PFCAC4-C9) revealed the most increase. Moreover, the levels of △[PFCAs] and the ratios of △[PFCAs] to their concentration before oxidation (△[PFCA]/[PFCA]before oxidation) indicated obvious spatial variations in the seawater and STP effluents. The higher levels of △[PFCAC4-C12] and the lower ratios of ∑△[PFCAC4-C12]/∑[PFAA]before oxidation were observed in the STP effluents, which implied that precursors might be decomposed during the sewage treatment process. These results suggested the STP effluents might have an important effect on the PFAAs levels of seawater.

Managing health risks of perfluoroalkyl acids in aquatic food from a river-estuary-sea environment affected by fluorochemical industry

Substantial perfluoroalkyl acids (PFAAs) production still occurs in China, and the consumption of aquatic products is a critical exposure pathway of PFAAs in humans. In this study, specimens of 16 freshwater and 40 marine species were collected in the river-estuary-sea environment affected by a mega fluorochemical industry park in China in 2015, and the edible tissues of these organisms were analyzed for PFAA levels. Perfluorooctanoic acid (PFOA) was the dominating contaminant with an overall contribution of more than 90%, and concentrations as high as 2161 ng/g wet weight (measured in the freshwater winkle). All species with the greatest PFOA levels were benthic. The trophic magnification factor (TMF) of PFOA was 1.10 for freshwater species and 1.28 for marine species, indicating that PFOA was slightly magnifying. Analysis of carbon source indicated that freshwater species were more benthic feeding, while marine species were more pelagic feeding. Aquatic food consumption screening values of PFOA were modified according to estimated daily intake (EDI) values, which generated recommendations for limited meal categories and the do-not-eat category. Thus, this study provides recommendations for mitigating the health risks of PFAA-contaminated aquatic food, ranging from food selection to consumption frequency and proper food processing.

Developmental exposure to a mixture of perfluoroalkyl acids (PFAAs) affects the thyroid hormone system and the bursa of Fabricius in the chicken

Perfluoroalkyl acids (PFAAs) are ubiquitous environmental contaminants and eggs and nestlings of raptors and fish-eating birds often contain high levels of PFAAs. We studied developmental effects of a mixture of ten PFAAs by exposing chicken embryos to 0.5 or 3 μg/g egg of each compound in the mixture. Histological changes of the thyroid gland were noted at both doses and increased expression of mRNA coding for type III deiodinase was found at 0.5 μg/g egg. Serum concentrations of the free fraction of thyroid hormones (T3 and T4) were reduced by the PFAA mixture at 3 µg/g egg, which is in line with a decreased synthesis and increased turnover of thyroid hormones as indicated by our histological findings and the decreased mRNA expression of type III deiodinase. The relative weight of the bursa of Fabricius increased at a dose of 3 μg/g egg in females. The bursa is the site of B-cell development in birds and is crucial for the avian adaptive immune system. Analysis of plasma and liver concentrations of the mixture components showed differences depending on chain length and functional group. Our results highlight the vulnerability of the thyroid hormone and immune systems to PFAAs.

Perfluoroalkyl acids (PFAAs): Distribution, trends and aquatic ecological risk assessment in surface water from Tagus River basin (Spain)

Rivers can receive the input of treated or untreated sewage effluents from wastewater treatment plants, urban and industrial discharges and agricultural run-off, becoming an important pathway for the transport and mobilization of pollutants to the oceans. In the present study, the occurrence of 20 PFAAs was determined in the water of Tagus River basin (Spain). PFAAs were detected in 76 out of 92 water samples collected during 5 years (2013–2018), being perfluorooctanesulfonic acid (PFOS) the predominant compound (<0.01–34 ng/L). The annual average PFOS concentrations (2.9–11 ng/L) detected in Tagus River were above the annual average environmental quality standards (AA-EQS) established in the Directive, 2013/39/EU (0.65 ng/L for inland surface waters) but below the maximum allowable concentration (MAC-EQS; 36000 ng/L). The levels of PFAAs detected in urban and industrial areas were statistically higher (p < 0.01) than those at background or remote areas. The mass flow rates amounted to <0.01–46 kg/y for PFOS and <0.01–22 kg/y for perfluorooctanoic acid (PFOA). A quantitative ecotoxicological risk assessment was conducted to evaluate the environmental potential risk related to PFAAs in the aquatic ecosystem. Risk characterization ratios (RCRwater, RCRsed and RCRoral, fish) were below 1 in all cases.

Sex differences in the association between perfluoroalkyl acids and liver function in US adolescents: Analyses of NHANES 2013–2016

Perfluoroalkyl acids (PFAAs) are persistent in the environment, highly bio-accumulative in the body, and likely hepatotoxic in humans. There is evidence of sex-specific physiological responses to PFAA exposure. However, epidemiological studies seldom stratify the analyses by sex. Given the high prevalence of liver disease in general population adolescents, this study was designed to determine whether or not there is association between exposure to PFAAs and biomarkers of liver function in adolescent participants of the 2013–2016 National Health and Nutrition Examination Survey, and whether or not such association is sex-specific. Multivariate linear regressions were performed to examine the association between single PFAAs [perfluorooctane sulfonic acid (PFOS); linear form of perfluorooctanoic acid (PFOA); perfluorohexane sulfonic acid (PFHxS); perfluorononanoic acid (PFNA)], and biomarkers of liver function — gamma glutamyltransferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin. Multivariate logistic regressions were performed to estimate adjusted odd ratios (aOR) of elevated ALT, AST and GGT. The study results show that, in females, there was a positive association of the highest PFOA quartile with increased ALT, AST and GGT, and the highest PFNA quartile with increased ALT and AST. Conversely, in male adolescents there was an association of the highest linear PFOA quartile with decreased ALT, and the highest PFNA quartile with ALT and AST. Females had higher odds of clinically-defined elevated ALT with increased PFOA (aOR = 1.79; 95% CI: 1.05, 3.04) or PFNA (aOR = 2.28; 95% CI: 1.08, 2.28), whereas males had decreased odds of clinically-defined elevated ALT with increased n-PFOA (aOR = 0.43; 95% CI: 0.20, 0.93) or PFNA (aOR = 0.5; 95% CI: 0.28, 0.89). In conclusion, there were sex differences in the association between serum PFAA levels and biomarkers of liver function. These results may provide support for analyzing sex-based adverse effects of PFAAs.

Assessing the contribution of atmospheric transport and tourism activities to the occurrence of perfluoroalkyl acids (PFAAs) in an Alpine Nature Reserve

Perfluoroalkyl acids (PFAAs) are ubiquitous in the global environment, even in remote regions. With increasing production and application of PFAAs in China, their distribution patterns have been widely reported, however with less attention to inland northwestern regions. Long-range transport and direct releases from local activities have been regarded as the main reasons for PFAAs distribution in such a remote area. To identify and quantify the contributions of different sources to PFAAs occurrences, an investigation was conducted in the Tianchi lake, nature reserve. A total of 20 water samples, 8 soil, 4 sediment and 10 fresh snow samples were collected and analyzed in 2015. The mean PFAAs concentrations were 3.38 ng L−1 in surface water, 1.06 ng g−1 dw in soil, 0.53 ng g−1 dw in sediment, and 3.31 ng L−1 in fresh snow, respectively. High levels of PFAAs were observed in surface water (15.41 ng L−1) from Western Tianchi pond and surface snow (14.24 ng L−1) from the site near a ski resort around Tianchi Lake indicating potential pollution by local human activities. The correlation between individual concentrations among water, soil and snow indicated the snow deposition as an important source. Although with limited sample size, principal component analysis associated with multiple linear regression (PCA-MLR) and positive matrix factorization (PMF) analyses have identified two major sources, which are characterized as tourism activities with dominance of perfluorooctanoic acid (PFOA) and long-range transport with abundant perfluorobutanoic acid (PFBA). Their contributions to total levels were 41% and 52%, respectively. These two sources contributed differently to the PFAAs presences in Tianchi and Western Tianchi Lakes. Source analysis indicates that the western Tianchi lake with a relatively small catchment was affected mainly by local activities.

A Review of Perfluoroalkyl Acids (PFAAs) in terms of Sources, Applications, Human Exposure, Dietary Intake, Toxicity, Legal Regulation, and Methods of Determination

Per- and polyfluoroalkyl substances (PFASs) are widely distributed across the world and are expected to be of concern to human health and the environment. The review focuses on perfluoroalkyl acids (PFAAs) and, in particular, on the most frequently discussed perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs). In this study, some basic information concerning PFASs is reviewed, focusing mainly on PFAAs (perfluoroalkyl acids). We have made efforts to systemize their division into groups according to chemical structure, describe their basic physicochemical properties, characterize production technologies, and determine potential human exposure routes with particular reference to oral exposure. A variety of possible toxicological effects to human health are also discussed. In response to increasing public concern about the toxicity of PFAAs, an evaluation of dietary intake has been undertaken for two of the most commonly known PFAAs: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). As summarized in this study, PFAAs levels need further assessment due to the science-based TWI standards laid down by the EFSA’s CONTAM Panel regarding the risk to human health posed by the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food (tolerable weekly intakes of PFOA and PFOS set up to 6 ng·kg−1·bw·week−1 and 13 ng·kg−1·bw·week−1, respectively). Current legislation, relevant legislation on PFAAs levels in food, and the most popular methods of analysis in food matrices are described.

Fate of a perfluoroalkyl acid mixture in an agricultural soil studied in lysimeters

Perfluoroalkyl acids (PFAAs) are environmental contaminants of concern in both food and drinking water. PFAA fate in agricultural soil is an important determinant of PFAA contamination of groundwater and crops. The fate of C4-C14 perfluorinated carboxylic acids (PFCAs) and two perfluorinated sulfonic acids (PFSAs) in an agricultural soil was studied in a field lysimeter experiment. Soil was spiked with PFAAs at four different levels and crops were planted. PFAA concentrations in soil were measured at the beginning and end of the growing season. Lysimeter drainage water was collected and analysed. The concentrations of all PFAAs decreased in the surface soil during the growing season, with the decrease being negatively correlated with the number of fluorinated carbons in the PFAA molecule. PFAA transfer to the drainage water was also negatively correlated with the number of fluorinated carbons. For the C11-C14 PFCAs most of the decrease in soil concentration was attributed to the formation of non-extractable residues. For the remaining PFAAs leaching was the dominant removal process. Leaching was concentration dependent, with more rapid removal from the soils spiked with higher PFAA levels. Model simulations based on measured Kd values under-predicted removal by leaching. This was attributed to mixture effects that reduced PFAA sorption to soil.

The occurrence of perfluoroalkyl acids in an important feed material (fishmeal) and its potential risk through the farm-to-fork pathway to humans.

Few studies have attempted to elucidate the occurrence of perfluoroalkyl acids (PFAAs) in animal feeds and how they play a role in human ingestion. Fishmeal was the most important animal-derived feed in global husbandry and may have been subjected to PFAA contamination considering the PFAAs' ubiquitous distribution in aquatic ecosystems. We collected ninety-two commercial fishmeal from the most important fishmeal-producing countries and found that Σ16PFAAs ranged from 0.65 to 85.5 ng/g (average: 18.2 ng/g, 12% moisture). PFOS still predominated, with unexpected high detection of PFUnDA. The wide occurrence of short-chain PFAAs (e.g., PFBA, PFBS) in fishmeal were found for the first time. From a geographical view, PFAA levels in fishmeal that originated from the Northern Hemisphere were significantly higher than those from the Southern Hemisphere (p < 0.01). Higher levels of under-studied long-chain PFAAs (PFNA, PFDA, PFUnDA, PFDoDA and PFTrDA) weighted more in industrialized areas than less industrialized areas, whereas the legacy PFAAs (PFOS, PFOA and PFHxS) were comparable among all regions. The estimated daily intake was calculated from animal feed to humans (via cultured fish) from 20 Chinese provinces by the Monte Carlo Simulation. A proportion of 29.8% of residents from the Fujian Province exceeded the EFSA's suggestion for PFOS ingestion.

Perfluoroalkyl acids in drinking water of China in 2017: Distribution characteristics, influencing factors and potential risks

Perfluoroalkyl acids (PFAAs) are a group of emerging persistent organic pollutants (POPs), which have been ubiquitously detected in the environmental media. However, national scale investigations on their occurrence and distribution in drinking water are still insufficient. In this study, we detected the 17 priority PFAAs in drinking water from 79 cities of 31 provincial-level administrative regions throughout China, and investigated their occurrence and distribution. Additionally, we also analyzed the influencing factors on their profiles, such as the existence of industrial sources, socioeconomic factors (population density and GDP), and assessed levels of risk associated with contaminated drinking water. On the national scale, the sum concentrations of the 17 PFAAs (∑17PFAAs) in drinking water was in a range of 4.49–174.93 ng/L with a mean value of 35.13 ng/L. Among the 17 individual PFAAs, perfluorobutanoic acids (PFBA) was the most abundant individual PFAAs with the median concentration of 17.87 ng/L, followed by perfluorooctanoic acid (PFOA, 0.74 ng/L), perfluorononanoic acid (PFNA, 0.40 ng/L) and perfluorooctane sulfonic acid (PFOS, 0.25 ng/L). The geographic distribution characteristic of ∑17PFAAs in drinking water was in a descending order of Southwestern China (57.67 ng/L) > Eastern coastal China (32.85 ng/L) > Middle China (29.89 ng/L) > Northwestern China (28.49 ng/L) > Northeastern China (22.03 ng/L), and in general, the existence of the industrial sources could positively affect the contamination levels of PFAAs in drinking water. The pollution level of PFAAs in drinking water also varied among the three different city levels (medium-sized city > big city > town). In towns, the positive correlations were observed between the population density and the ∑17PFAAs (R2 = 0.45, p < 0.01), and the individual concentration of PFHxA, PFBS, and PFOA (p < 0.01). Moreover, besides PFAAs in Yunnan, Jiangsu, and Jiangxi, concentrations of related PFAAs in drinking water from 28 provinces were less than the suggested drinking water advisories. The relatively higher concentrations of PFAAs in Yunnan, Jiangsu, and Jiangxi suggest that further studies focusing on their sources and potential health risk to humans are needed.

Factors associated with exposure of pregnant women to perfluoroalkyl acids in North China and health risk assessment

Perfluoroalkyl acids (PFAAs) have been frequently found in blood of pregnant women, but the predictors and potential health risk have not been well studied in China. We recruited 534 pregnant women in Tangshan City of Hebei Province in North China between 2013 and 2014 and measured five PFAAs in serum during their early term of pregnancy, including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluoro‑n‑undecanoic acid (PFUdA), and perfluorononanoic acid (PFNA). We explored the factors associated with the levels of serum PFAAs and assessed associated health risks. Food consumption information was obtained by food frequency questionnaire covering 100 items. Multiple linear regression model was used to determine the associations of sociodemographic, anthropometric, and food factors with the concentrations of serum PFAAs. Some PFAAs in serum were positively associated with age and body mass index (BMI). Consumption of beans, aquatic products, and eggs was positively associated with the concentrations of several PFAAs after adjusting for important covariates. Pregnant women who ate more cereal, vegetables, mushrooms and alga tended to have lower levels of serum PFOA, PFOS and PFNA. The Hazard index (HI) for reproductive toxicity and developmental toxicity was below 0.8, and the HI for hepatotoxicity beyond 1 was found in 0.37% of pregnant women. These results suggested that age, BMI, and some food consumption were predictors for the exposure to PFAAs in Chinese pregnant women. More attention should be paid to the hepatotoxicity for these exposures.

Conditioning on Parity in Studies of Perfluoroalkyl Acids and Time to Pregnancy: An Example from the Danish National Birth Cohort.

Background:Previous studies have investigated the associations between perfluoroalkyl acids (PFAAs) in women and time to pregnancy (TTP). Inconsistent results may be explained by differences in conditioning on parity.Objectives:We used causal directed acyclic graphs to illustrate potential confounding related to previous pregnancies and exposure measurement error due to differences in the interpregnancy interval in pregnancy-based studies that include parous women. We exemplified the potential importance of these issues using data from the Danish National Birth Cohort.Methods:We used discrete time survival models to estimate associations between maternal plasma PFAAs in early pregnancy and TTP in 638 nulliparous and 613 parous women.Results:PFAA quartiles were not associated with the TTP in nulliparous women. In parous women, higher PFAA quartiles were associated with longer TTP. The strongest associations were estimated for perfluorohexane sulfonate and perfluorooctane sulfonate. PFAA concentrations were higher in women with longer interpregnancy intervals. Accounting for the interpregnancy interval attenuated the estimated associations.Conclusions:Associations between PFAAs and TTP in parous women may be biased by confounders related to previous pregnancies and exposure measurement error. To avoid these biases, studies that include parous women may need to condition on a) common causes of PFAAs and the TTP in the index pregnancy, b) previous births (a descendant of a collider), c) PFAA levels or common causes of PFAA levels and the TTP in the previous pregnancy (to alleviate collider stratification bias caused by conditioning on previous births), and d) the interpregnancy interval (in pregnancy-based studies). Alternatives would be to restrict studies to nulliparous women or to use toxicokinetic modeling to correct exposure estimates in parous women. These recommendations may be extended to studies of other chemicals with similar toxicokinetic properties. https://doi.org/10.1289/EHP1493