Effects Of Perfluoroalkyl Acids Research Articles

Effects of perfluoroalkyl acids on nitrogen release, transformation and microbial community during the debris decomposition of Alisma orientale and Iris pseudacorus

The release of nutrients into water during debris decomposition is a serious concern, leading to severe environmental pollution. To understand the effects of extensively present emerging contaminants (such as perfluoroalkyl acids (PFAAs)) on the nitrogen (N) release and transformation, the concentration dynamics of different N species in surrounding water and changes in microbial communities on biofilm during the 70-days decomposition of two typical submerged macrophyte (Alisma orientale and Iris pseudacorus) debris were studied. The results showed that large amounts of N species (especially organic and ammonium N) were released during decomposition. PFAAs with a low concentration (1 μg/L) could stimulate total N (TN) release, whereas PFAAs with a high concentration (≥ 10 μg/L) might have inhibited TN release. Higher intensities of ammonification, nitrosification, and denitrification, but lower intensities of nitrification were observed in water in the presence of PFAAs. Microbiota associated with organic matter hydrolysis, nitrification and denitrification, as well as PFAA degrading/tolerant bacteria, were beneficial and might have occupied dominant states. Redundancy analysis showed that PFAAs were positively associated with the amounts of nitrate, denitrifiers, and azotobacteria but negatively correlated with the TN, ammonia, nitrite, organic N, and nitrosobacteria amounts (p = 0.0002). The complete N metabolism pathway was identified using PICRUSt and KEGG. Functional genes related to ammonification (0.76‰–2.16‰), N reduction (3.43‰–5.05‰), and assimilation (0.81‰–2.16‰) were more abundant than others in all treatments. This study provides a more comprehensive understanding of N cycling during debris decomposition under the increasingly intractable threat of emerging contaminants in aquatic ecosystems.

Changes in hepato-renal gene expression in microminipigs following a single exposure to a mixture of perfluoroalkyl acids.

It is evident that some perfluoroalkyl acids (PFAAs), a group of globally dispersed pollutants, have long biological half-lives in humans and farm animals. However, the effects of PFAAs in domestic animals have not been fully elucidated. The present study investigated how exposure to a single dose of a mixture of 10 PFAAs influenced hepatic and renal gene expression and histopathology, as well as plasma clinical biochemistry, in microminipigs (MMPigs) over 21 days. In animals treated with PFAAs, the mRNA expression of twelve genes related to fatty acid metabolism was upregulated in the kidney, while only few of these genes were induced in the liver. The expression of several kidney injury-associated genes such as, IGFBP1, IGFBP6, GCLC X2, GCLC X3, MSGT1, OLR1 was upregulated in the kidney. Interestingly, the expression of IGFBP-genes was differentially altered in the liver and kidney. Our findings thus identified hepato-renal gene expression changes in MMPigs that were associated with various molecular pathways including peroxisome proliferation, lipid metabolism, kidney injury, and apoptosis. Furthermore, serum HDL levels were significantly decreased following exposure to PFAAs, whereas no significant histopathological changes were detected, as compared to the vehicle group. Taken together, the present study provided the first indication that a single exposure to a mixture of PFAAs can produce changes in MMPig renal gene expression that were observed three weeks post exposure, suggesting that more attention should be paid to the kidney as a primary target organ of PFAAs.

The Effects of Perfluoroalkyl Acids (Pfaas) Exposure in Utero on IGF2/H19 DNA Methylation in Cord Blood

The Effects of Perfluoroalkyl Acids (Pfaas) Exposure in Utero on IGF2/H19 DNA Methylation in Cord Blood

Perfluoroalkyl acids (PFASs) and thyroid disruption in US adults (NHANES 2007-2008)

Background: Perfluoroalkyl acids (PFASs) are known thyroid toxicants in animal studies, but the effect of PFASs on human thyroid hormones is unclear. Aims: To examine PFAS-thyroid hormone associations in a representative, population-based sample of US adults. We hypothesized that people who had undiagnosed autoimmune hypothyroidism, defined as thyroid peroxidase antibody (TPOAb) >9 IU/mL, and low iodine status would be susceptible to PFAS-induced thyroid disruption because of their compromised capacity to regulate thyroid hormone production. Methods: Our sample included 1,525 US adults (?18 years) from the 2007-2008 NHANES study with available serum PFAS and thyroid hormone data, excluding those with a previously-diagnosed thyroid condition and those taking thyroid medications. We evaluated associations between individual serum PFASs (PFHxS, PFNA, PFOA and PFOS), and thyroid hormones (fT4, fT3, fT3/fT4, and TSH) using multivariable linear regression. Models were stratified by TPOAb status (high: ? 9 IU/mL serum, normal < 9 IU/mL), and iodine status (normal: > 100 ?g/L urine, low: ? 100 ?g/L iodine urine), and were adjusted for age, sex, urinary cotinine, race/ethnicity, time of day of serum collection, and, for women, pregnancy and menopause status. Results: Median serum PFAS concentrations, in ng/g, were: 1.9 (PFHxS), 1.5 (PFNA), 4.3 (PFOA) and 13.9 (PFOS). 426 (28%) of participants had low iodine status, 113 (7%) had high TPOAb, and 26 (2%) had both low iodine and high TPOAb. Higher concentrations of all four PFASs were significantly associated (?=0.05) with lower fT4, higher fT3 (PFOS and PFOA only), higher fT3/fT4, and higher TSH in the low iodine / high TPOAb group only. A weak positive association between PFOA and TSH was also found in participants who had low iodine but normal TPOAb. Conclusions: Exposures to PFASs are associated with hypothyroid disruption in adults who have both low iodine and undiagnosed autoimmune hypothyroidism, a population representing about 2.2% (5 million) of US adults.

Effects of perfluoroalkyl acids on the function of the thyroid hormone and the aryl hydrocarbon receptor

Perfluoroalkyl acids (PFAAs) are perfluorinated compounds that widely exist in the environment and can elicit adverse effects including endocrine disruption in humans and animals. This study investigated the effect of seven PFAAs on the thyroid hormone (TH) system assessing the proliferation of the 3,3′,5-triiodo-l-thryonine (T3)-dependent rat pituitary GH3 cells using the T-screen assay and the effect on the aryl hydrocarbon receptor (AhR) transactivation in the AhR-luciferase reporter gene bioassay. A dose-dependent impact on GH3 cells was observed in the range 1 × 10−9–1 × 10−4 M: seven PFAAs (perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA)) inhibited the GH3 cell growth, and four PFAAs (PFOS, PFHxS, PFNA, and PFUnA) antagonized the T3-induced GH3 cell proliferation. At the highest test concentration, PFHxS showed a further increase of the T3-induced GH3 growth. Among the seven tested PFAAs, only PFDoA and PFDA elicited an activating effect on the AhR. In conclusion, PFAAs possess in vitro endocrine-disrupting potential by interfering with TH and AhR functions, which need to be taken into consideration when assessing the impact on human health.

Effects of perfluoroalkyl acids on the function of the thyroid hormone and the aryl hydrocarbon receptor

Perfluoroalkyl acids (PFAAs) are perfluorinated compounds that widely exist in the environment and can elicit adverse effects including endocrine disruption in humans and animals. This study investigated the effect of seven PFAAs on the thyroid hormone (TH) system assessing the proliferation of the 3,3',5-triiodo-L-thryonine (T3)-dependent rat pituitary GH3 cells using the T-screen assay and the effect on the aryl hydrocarbon receptor (AhR) transactivation in the AhR-luciferase reporter gene bioassay. A dose-dependent impact on GH3 cells was observed in the range 1×10(-9)-1×10(-4) M: seven PFAAs (perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA)) inhibited the GH3 cell growth, and four PFAAs (PFOS, PFHxS, PFNA, and PFUnA) antagonized the T3-induced GH3 cell proliferation. At the highest test concentration, PFHxS showed a further increase of the T3-induced GH3 growth. Among the seven tested PFAAs, only PFDoA and PFDA elicited an activating effect on the AhR. In conclusion, PFAAs possess in vitro endocrine-disrupting potential by interfering with TH and AhR functions, which need to be taken into consideration when assessing the impact on human health.

The Progress in Environmental Distributions and Toxicological Effects of Perfluoroalkyl Acids

Perfluorinated compounds(PFCs)are widely used in industry and consumer products.The high-energy carbon-fluorine(C-F)bond renders these compounds resistant to hydrolysis,photolysis,microbial degradation,as well as metabolism by animals and makes them a new kind of persistent organic compound.PFCs have been detected in various environmental samples and in tissues or blood from human population and wildlife in recent years.Concern about PFCs in recent years is growing for their bioaccumulation and potentially health risk and they have become research hotspots in the field of environmental,ecotoxicological science,and etc.This review provides an overview of the current pollution conditions of perfluoroalkyl acids in abiotic and biotic matrices,the transform and metabolism of these compounds in organism and the recent advances in toxicological studies of PFCs.The present existing problems and the trends of future research on PFCs are also discussed in this review to provide more information for the further study of these compounds.

Use of the humanized PPARa transgenic mouse models to study the effects of perfluoroalkyl acids

Use of the humanized PPARa transgenic mouse models to study the effects of perfluoroalkyl acids