Perfluorinated Compounds

In this study, we report for the first time, concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in sediments from a South African environment, particularly for the
largest  catchment  areas  of  the  Western  Cape,  South  Africa,  an  area  associated  with  the  largest agricultural  sector  with  some  of  the  produce  and  end-products  intended  for  the  international  markets.
Sample  preparation  and  analysis  were  based  on  the  ISO  25101:  2009(E)  method,  using  solid  phase extraction  (SPE)  followed  by  liquid  chromatography  combined  with  electrospray  tandem  mass
spectrometry  (LC-MS/MS).  Sediment  grain  size  analysis,  core  water  characteristics  and  percent  total organic carbon were also quantified. From the results, PFOS and PFOA were observed in all the river
sediment samples and were found in concentrations up to 19 ng/g and 187 ng/g for Salt River, 121 ng/g and 772 ng/g for Diep River, and 75 ng/g and 193 ng/g  for Eerste River,  for both PFOS and PFOA,
respectively. Some of these concentrations are higher than those previously reported in similar studies in various  countries;  this  suggests  there  is  cause  for  concern.  Although  sediment  has  a  poor  sorption capacity  for  both  PFOS  and  PFOA  in  comparison  with  plants,  the  prevalence  of  PFOS  and  PFOA  in sediment samples from rivers from which irrigation water is sourced for agricultural purposes, indicates a risk of agricultural produce contamination.

High yield monomeric tetrafluoroethylene may be recovered from polytetrafluoroethylene and polytetrafluoroethylene composites by pyrolyzing the polymer in the presence o high temperature steam. The steam acts as a condensable carrier gas for low molecular weight pyrolysis products and should be present in an amount such that the ratio of steam to pyrolysis products is at least one to one. The steam also acts as a means for heating the polymer to the necessary decomposition temperatures.  This method is environmentally effective for the recycle of polymers.

Besides water and sunlight, plants and/or crops also require an assortment of dissimilar nutrients/elements to grow. Thus, some of these nutrients have been classified as essential or macronutrients, [e.g. calcium (Ca), magnesium (Mg) and sulphur (S)], for they facilitate plant growth; while others, such as copper (Cu), iron (Fe), zinc (Zn), etc., are considered as micronutrients. However, it is apparent now that plants are exposed to a variety of other chemical compounds, including a range of persistent organic pollutants (POPs) and perfluoroalkyl substances (PFASs), which have been found in several plants. Hence, it has been common knowledge that mechanisms, such as mass flow, diffusion, etc., facilitated by plant root systems, have allowed the translocation of these nutrients and pollutants into plants, although other researchers have argued that roots on their own cannot elucidate the dissemination of these chemical constituents into plants. This dissension remained until the discovery of aquaporins (AQPs), which ultimately led to numerous AQPs being identified in plants. Thus, the aim of this
review is to present an overview on the progress made thus far in attempting to understand the possibility of these proteins (i.e. AQPs) being the gateway that conduits nutrients, POPs and PFASs into plants; however, the gathered evidence currently remains rudimentary and limited, suggesting that further research is required to elucidate plant AQPs involvement at this stage in POP transportation and storage in plants.

Between the late 1940s and early 1950s, humans manufactured polyfluoroalkyl compounds (PFCs) using electrochemical fluorination and telomerisation technologies, whereby hydrogen atoms are
substituted by fluorine atoms, thus conferring unnatural and unique physicochemical properties to these compounds. Presently, there are wide ranges of PFCs, and owing to their bioaccumulative properties, they have been detected in various environmental matrices and in human
sera. It has thus been suggested that they are hazardous. Hence, this review aims at highlighting the recent development in PFC research, with a particular focus on perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), the most studied and predominantly found PFCs
in various environmental matrices, although recent reports have included perfluorobutane sulfonate (PFBS), which was previously regarded as innocuously harmless, when compared to its counterparts, PFOA and PFOS. As such, proper investigations are thus required for a better
understanding of short-chain PFC substitutes, which have been suggested as suitable replacements to long-chained PFCs, although these substitutes have also been suggested to pose various health risks comparable to those associated with long-chain PFCs. Similarly, several novel technologies, such as PFC reduction using zero-valent iron, including removal at point of use, adsorption and coagulation, have been proposed. However, regardless of how efficient removers some of these techniques have proven to be,short-chain PFCs remain a challenge to overcome for scientists, in this regard.

Fluorinated organic chemicals have a wide variety of industrial and consumer applications. For long time perfluorooctane sulfonate and perfluorooctanoic acid have been used as precursors for manufacture of such chemicals. However, these C 8 chain compounds have been demonstrated to be toxic, persistent, and bioaccumulative, thus inducing their phase-out. Currently, C 6 telomer based fluorocarbon surfactants are considered better alternatives to C 8 products because of their low bioaccumulability. But, their high persistency suggests that in the near future their concentrations will increase in the environment and in industrial waste. Being a solid state non-thermal technology, mechanochemical treatment is a good candidate for the destruction of emerging C 6 fluorotelomers in solid waste. In the present study, 6:2 fluorotelomer sulfonate is effectively destroyed (~100%) in rapid manner (<1 h) by high energy ball milling with KOH. Stoichiometric fluoride formation confirms its entire mineralization, assuring that no toxic by-products are generated. Reaction mechanism and kinetics indicate that effective mineralization of the perfluorinated moiety is obtained thanks to a rapid CF 2 " flake-off " process through radical mechanism.

This study examined the prevalence of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in river water samples (n ¼ 56) and suspended solids (n ¼ 5) from three major Western Cape
rivers, in South Africa. Solid phase extraction (SPE) followed by liquid chromatography combined with electrospray tandem mass spectrometry (LC-MS/MS) using an analytical method developed in ISO
25101 (2009), PFOS and PFOA concentration in river water and in suspended solids from the rivers was investigated and quantified. From the results, PFOA and PFOS were detected in all the river
water samples and were found in concentrations up to 314 and 182 ng/L for Diep River; 390 and 47 ng/L for Salt River; and 146 and 23 ng/L for Eerste River, respectively. In suspended solids, concentrations for PFOS and PFOA were 28 and 26 ng/g for Diep River; 16 and less than limit of
detection for Eerste River; and 14 and 5 ng/g for Salt River, respectively. Some of these concentrations are higher than those previously reported in similar studies in various countries, and this suggests there is a cause for concern, in the Western Cape, South Africa, particularly in
catchments where river and ground water is drawn for agricultural purposes in the province.

To examine the cross-sectional association between serum perfluorooctanate (PFOA), perfuorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonate (PFHxS) concentrations with self-reported memory impairment in adults and the interaction of these associations with diabetes status. Cross-sectional study. Population-based in Mid-Ohio Valley, West Virginia following contamination by a chemical plant. The C8 Health Project collected data and measured the serum level of perfluoroalkyl acids (PFAAs) of 21 024 adults aged 50+ years. Self-reported memory impairment as defined by the question &#39;have experienced short-term memory loss?&#39; A total of 4057 participants self-reported short-term memory impairment. Inverse associations between PFOS and PFOA and memory impairment were highly statistically significant with fully adjusted OR=0.93 (95% CI 0.90 to 0.96) for doubling PFOS and OR=0.96 (95% CI 0.94 to 0.98) for doubling PFOA concentrations. Comparable inve...

Perfluorinated chemicals (PFCs) are attracting increasing concern due to their chemical stability and toxicity, which make them classifiable as persistent organic pollutants. However, such compounds are employed for the manufacture of many industrial and consumer products, hence their substitution is not possible in the near future. Suitable technologies for PFCs environmentally sound management are necessary. High energy ball milling with KOH has been proved to obtain PFCs safe destruction, but with excessive reagent. In the present study, a Waste-to-Materials solution is proposed: PFCs are co-milled with stoichiometric amounts of La2O3 and thus are fully converted into LaOF, a noteworthy luminescent material with many potential industrial applications. Reaction mechanism is also investigated: Ball milling process activates La2O3; this latter provokes oxidation to CO2 and carbonization of PFCs; fluorides are incorporated into the La2O3’s lattice to form the oxyfluoride. Interestingly, kinetic analysis suggests that the mechanical activation of La2O3 might follow a zeroth-order reaction rate.

Methods to predict the bioaccumulation potential of per- and
polyfluorinated alkyl substances (PFAS) are sorely needed, given
the proliferation of these substances and lack of data on their properties and behavior. Here, we test whether molecular docking, a technique where interactions between proteins and ligands are simulated to predict both bound conformation and interaction affinity, can be used to predict PFAS binding strength and biological half-life. We show that an easy-to-implement docking program, Autodock Vina, can successfully redock perfluorooctanesulfonate (PFOS) to human serum albumin with deviations smaller than 2 Å. Furthermore, predicted binding strengths largely fall within one standard deviation of measured values for perfluorinated alkyl acids (PFAAs). Correlations with half-lives suggest both membrane partitioning and protein interactions are important, and that serum albumin is only one of a number of proteins controlling the fate of these chemicals in organisms. However, few data are available for validation of our approach as a broad screening tool, and available data are highly variable. We therefore call for collection of new data, particularly including proteins other than serum albumin and substances beyond perfluorooctanoic acid (PFOA) and PFOS. The methods we discuss in this work can serve as a framework for guiding such data collection.

To examine the cross-sectional association between serum perfluorooctanate (PFOA), perfuorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonate (PFHxS) concentrations with self-reported memory impairment in adults and the interaction of these associations with diabetes status. Cross-sectional study. Population-based in Mid-Ohio Valley, West Virginia following contamination by a chemical plant. The C8 Health Project collected data and measured the serum level of perfluoroalkyl acids (PFAAs) of 21 024 adults aged 50+ years. Self-reported memory impairment as defined by the question &#39;have experienced short-term memory loss?&#39; A total of 4057 participants self-reported short-term memory impairment. Inverse associations between PFOS and PFOA and memory impairment were highly statistically significant with fully adjusted OR=0.93 (95% CI 0.90 to 0.96) for doubling PFOS and OR=0.96 (95% CI 0.94 to 0.98) for doubling PFOA concentrations. Comparable inve...

recent research concluded that one of the perfluoroalkyl amine compounds so-called perfluorotributylamine (PFTBA) has a global warming potential of 71001 (seven thousands and one hundred) and an atmospheric lifetime of at least 500 years.
This conclusion calls immediate attention towards PFTBA when one consider that the most significant scientific global concern of the last two decades has been global warming and especially greenhouse gases (GHGs) like CO2, CH4 and N2O

Objectives To examine the cross-sectional association between serum perfluorooctanate (PFOA), perfuorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonate (PFHxS) concentrations with self-reported memory impairment in adults and the interaction of these associations with diabetes status.


Design Cross-sectional study.


Setting Population-based in Mid-Ohio Valley, West Virginia following contamination by a chemical plant.


Participants The C8 Health Project collected data and measured the serum level of perfluoroalkyl acids (PFAAs) of 21 024 adults aged 50+ years.


Primary outcome measure Self-reported memory impairment as defined by the question ‘have experienced short-term memory loss?’


Results A total of 4057 participants self-reported short-term memory impairment. Inverse associations between PFOS and PFOA and memory impairment were highly statistically significant with fully adjusted OR=0.93 (95% CI 0.90 to 0.96) for doubling PFOS and OR=0.96 (95% CI 0.94 to 0.98) for doubling PFOA concentrations. Comparable inverse associations with PFNA and PFHxS were of borderline statistical significance. Inverse associations of PFAAs with memory impairment were weaker or non-existent in patients with diabetes than overall in patients without diabetes.


Conclusions An inverse association between PFAA serum levels and self-reported memory impairment has been observed in this large population-based, cross-sectional study that is stronger and more statistically significant for PFOA and PFOS. The associations can be potentially explained by a preventive anti-inflammatory effect exerted by a peroxisome proliferator-activated receptor agonist effect of these PFAAs, but confounding or even reverse causation cannot be excluded as an alternative explanation.

In recent years, many new studies have evaluated associations between environmental pollutants and child health. This review aims to provide a broad summary of this literature, comparing the state of epidemiological evidence for the effects of a wide range of environmental contaminants (air pollutants, heavy metals, organochlorine compounds, perfluoroalkyl substances, polybrominated diphenyl ethers, pesticides, phthalates and bisphenol A) on child health outcomes. The review addresses effects on foetal growth and prematurity, neurodevelopment, respiratory and immune health, and childhood growth and obesity. Findings of recent prospective studies and meta-analyses have corroborated previous good evidence, often at lower exposure levels, for effects on foetal growth of air pollution and polychlorinated biphenyls (PCBs), for neurotoxic effects of lead, methylmercury, PCBs and organophosphate pesticides, and for respiratory health effects of air pollution. Moderate evidence has emerged for a potential role of environmental pollutants in attention deficit hyperactivity disorder and autism (lead, PCBs, air pollution), respiratory and immune health (dichlorodiphenyldichloroethylene - DDE - and PCBs), and obesity (DDE). In addition, there is now moderate evidence that certain chemicals of relatively recent concern may be associated with adverse child health outcomes, specifically perfluorooctanoate and foetal growth, and polybrominated diphenyl ethers and neurodevelopment. For other chemicals of recent concern, such as phthalates and bisphenol A, the literature is characterised by large inconsistencies preventing strong conclusions. In conclusion, since most of the recent literature evaluates common exposures in the general population, and not particularly high exposure situations, this accumulating body of evidence suggests that the unborn and young child require more protection than is currently provided. Large, coordinated research efforts are needed to improve understanding of long-term effects of complex chemical mixtures.