Understanding potential exposure sources of perfluorinated carboxylic acids in the workplace.

This paper integrates perspectives from analytical chemistry, environmental engineering, and industrial hygiene to better understand how workers may be exposed to perfluorinated carboxylic acids when handling them in the workplace in order to identify appropriate exposure controls. Due to the dramatic difference in physical properties of the protonated acid form and the anionic form, this family of chemicals provides unique industrial hygiene challenges. Workplace monitoring, experimental data, and modeling results were used to ascertain the most probable workplace exposure sources and transport mechanisms for perfluorooctanoic acid (PFOA) and its ammonium salt (APFO). PFOA is biopersistent and its measurement in the blood has been used to assess human exposure since it integrates exposure from all routes of entry. Monitoring suggests that inhalation of airborne material may be an important exposure route. Transport studies indicated that, under low pH conditions, PFOA, the undissociated (acid) species, actively partitions from water into air. In addition, solid-phase PFOA and APFO may also sublime into the air. Modeling studies determined that contributions from surface sublimation and loss from low pH aqueous solutions can be significant potential sources of workplace exposure. These findings suggest that keeping surfaces clean, preventing accumulation of material in unventilated areas, removing solids from waste trenches and sumps, and maintaining neutral pH in sumps can lower workplace exposures.

Development and validation of a wipe test method using liquid chromatography with tandem mass spectrometry for the determination of Perfluorooctanoate (PFO) on various surfaces.

Perfluorooctanoate (PFO) is the anion of perfluorooctanoic acid. As the ammonium salt, PFO has been used for 50 years as a processing aid in the commercial production of perfluorinated and highly fluorinated polymers. To assess the effectiveness of industrial hygiene controls in processes involving PFO products and intermediates, a wipe test was developed and validated to determine quantitatively the PFO concentration on six surfaces: stainless steel, polycarbonate, Formica, butyl acid suit material, laminated disposable suit material, and a painted surface. Acceptable recovery and precision results were obtained for nonporous surfaces, such as stainless steel, polycarbonate, Formica, acid suit material, and painted surfaces on a 10-cm x 10-cm surface. The analytical method was evaluated over a range of 1 to 23 ng/cm2, or 100 to 2300 ng/100 cm2. The reporting limit for the method was 100 ng/wipe.

Vapor pressure determinations of 8-2 fluorortelomer alcohol and 1-H perfluorooctane by capillary gas chromatography Relative retention time versus headspace methods.

Two distinctly different capillary gas chromatographic methods were used to determine the vapor pressure of 8-2 fluorotelomer alcohol (8-2 FTOH) and 1-H perfluoroheptane at several temperatures. For measurements employing the relative retention-time method, a short polymethylsiloxane column was used from 25 to 65 degrees C. For the 8-2 FTOH, hydrocarbon alcohols and perfluoroalcohols were used as reference standards. For 1-H perfluoroheptane, hydrocarbons were used as reference standards. Vapor pressure estimates could differ by as much as an order of magnitude compared to published results determined by other (nonchromatographic) methods. This variance may be a function of solvent-solute interactions within the gas chromatographic column and the infinite dilution assumption, both used in the relative retention method. For comparison, data were also gathered using headspace gas chromatography (GC) with atomic emission detection (AED). The results from this novel GC/AED method were consistent with prior nonchromatographic results. A discussion of why headspace is the preferred technique for the determination of vapor pressure for fluorinated compounds is presented.

Suicídios na pré-adolescência, adolescência e em adultos jovens: comparação da capital Goiânia com o município de Mineiros / Suicides in pre-adolescence, adolescence and young adults: comparison between Goiânia and Mineiros / Suicidios en la preadolescencia, adolescencia y adultos jóvenes: comparación de la capital Goiânia con el municipio de Mineiros

O suicídio é um ato que interroga a relação de sentido com a existência, assunto geralmente evitado pela sociedade. Considerando o aumento do suicídio entre indivíduos jovens bem como as altas prevalências na região Centro-Oeste do país, neste estudo, objetivou-se relacionar os índices de suicídios da capital Goiânia a uma cidade do interior da região Centro-Oeste (Mineiros-GO), nos períodos da pré-adolescência, adolescência e em adultos jovens. Para isso, foi consultada base de dados do Ministério da Saúde, em um período de 10 anos (2006 a 2015). Fatores como sexo e causa da morte foram considerados. Os dados analisados, quantitativamente, permitiram apontar um número maior de suicídios entre os adultos jovens, em relação ao período da pré-adolescência e adolescência, o que pode ser relacionado com algumas características desses momentos contíguos da vida dos sujeitos e de seus contextos locais. Os dados também indicaram que o município de Mineiros apresentou índices maiores em comparação com a capital se relacionado ao número de mortes por enforcamento. Contudo, os dados permitem fortalecer de que as políticas públicas se fazem precisas e urgentes para atendimento desse público, não somente em grandes centros urbanos, mas também em municípios de pequeno e médio porte do interior dos estados brasileiros.

Suicide is an act that questions the relationship of meaning to existence, a subject usually associated with the individual avoiding social interactions. Considering the increase in suicide among young individuals as well as the high prevalence in the central-western region of the country, this study compared the suicide rates of the capital Goiânia to a city in the countryside of the Central-west region (Mineiros-Goiás), between periods of pre-adolescence, adolescence and in young adults. For this, a database of the Ministry of Health was consulted for a 10-year period (2006 to 2015). Factors such as gender and cause of death were considered. The data analyzed quantitatively and qualitatively showed an increasing number of suicides among young adults compared to pre-adolescence and adolescence, which may be related to some characteristics of these contiguous moments of the subjects' lives and their local contexts. The data also showed that the municipality of Mineiros presented higher indices compared to the capital regarding the number of deaths by hanging. However, the data reinforces that public policies are needed and urgent to serve this public not only in large urban centers, but also in small and medium-sized municipalities in the countryside of Brazilian states.

El suicidio es un acto que interroga la relación de sentido con la existencia, asunto evitado generalmente por la sociedad. Considerando el aumento de la tasa de suicidio entre individuos jóvenes y las altas prevalencias en la región Centro-oeste de Brasil, el presente estudio objetivó comparar las tasas de suicidios de la capital Goiânia con una ciudad del interior de la región Centro-oeste (Mineros, Goiás), entre períodos de preadolescencia, adolescencia y en adultos jóvenes. Para ello, se consultó la base de datos del Ministerio de la Salud en un período de 10 años (de 2006 a 2015). Se consideraron factores como el sexo y la causa de la muerte. Los datos analizados cuantitativamente permitieron señalar un número creciente de suicidios entre los adultos jóvenes en relación al período de la preadolescencia y la adolescencia, lo que puede relacionarse con algunas características de esos momentos contiguos de la vida de los sujetos y de sus contextos locales. Los datos también señalaron que el municipio de Mineiros presentó tasas más altas en comparación a la capital si se relaciona al número de muertes por ahorcamiento. Sin embargo, los datos permiten fortalecer que las políticas públicas son necesarias y urgentes para atender a este público no solo en grandes centros urbanos, sino también en municipios pequeños y medianos en el interior de los estados brasileños.

Efficient "total" extraction of perfluorooctanoate from polytetrafluoroethylene fluoropolymer.

To determine the optimum conditions for the complete extraction of perfluorooctanoate (PFO) from polytetrafluoroethylene fluoropolymers, sample preparation and pressurized solvent extraction (PSE) conditions were investigated. Solvent extraction temperature, solvent residence time, relaxation time between extractions, and the effects of heating before PSE showed that methanol at 150 degrees C extraction temperature and a 12 min solvent residence time were the most efficient conditions. Preheating the polymer before extraction at 150 degrees C for 24 h significantly enhanced the quantity of PFO removed. Heating above 150 degrees C resulted in loss of PFO. PFO was determined by liquid chromatography with tandem mass spectrometry.

Comparison of pressurized solvent and reflux extraction methods for the determination of perfluorooctanoic acid in polytetrafluoroethylene polymers using LC-MS-MS.

Both pressurized solvent extraction (PSE) and reflux extraction in various solvents were used to select the most efficient system for the determination of the quantity of perfluorooctanoic acid (PFOA) present in polytetrafluoroethylene polymers. After evaporating the solvent, PFOA was determined using liquid chromatography tandem mass spectrometry. Ethanol, water and methanol gave comparable results and were shown to be good solvents for this extraction. Acetonitrile was a reasonable solvent using the reflux extraction method, but not with PSE. Chloroform resulted in poor recovery for both extraction methods. PSE proved to be the more efficient extraction method.

Vapor pressure and intramolecular hydrogen bonding in fluorotelomer alcohols.

Vapor pressure and aqueous solubility are important parameters used to estimate the potential for transport of chemical substances in the atmosphere. For fluorotelomer alcohols (FTOHs), currently under scrutiny by environmental scientists as potential precursors of persistent perfluorocarboxylates (PFCAs), vapor pressure is the more significant property since these compounds are only very sparingly soluble in water. We have measured the vapor pressures of a homologous series of fluorotelomer alcohols, F(CF2CF2)nCH2CH2OH (n = 2-5), in the temperature range 21-250 degrees C by three independent methods: (a) a method suitable for very low vapor pressures at ambient temperatures (gas-saturation method), (b) an improved boiling point method at controlled pressures (Scott method), and (c) a novel method, requiring milligram quantities of substance, based on gas-phase NMR, a technique largely unfamiliar to chemists and holding promise for studies of relevance to environmental chemistry. The concordant values obtained indicate that recently published vapor pressure data overestimate the vapor pressure at ambient temperature, and therefore the volatility, of this series of fluorinated compounds. It was suggested that substantial intramolecular -O-H...F- hydrogen bonding between the hydroxylic proton and the two fluorines next to the ethanol moiety was responsible for their putative high volatility. Therefore, we have used gas-phase NMR, gas-phase FTIR, 2D NMR heteronuclear Overhauser effect measurements, and high-level ab initio computations to investigate the intramolecular hydrogen bonding in fluorotelomer alcohols. Our studies unequivocally show that hydrogen bonding of this type is not significant and cannot contribute to and cause unusual volatility. The substantially lower vapor pressure at ambient temperatures than previously reported resulting from our work is important in developing a valid understanding of the environmental transport behavior of this class of compounds.