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Perfluorooctanoic acid (PFOA) is a perfluoroalkyl acid found in > 99% of Americans. Its health effects are unknown. Prior estimates of serum half-life range from 2.3 to 3.8 years.We assessed the impact of years of residence and years since residing in the study area on serum PFOA concentration in a sample of current and former residents who were exposed to PFOA emissions from an industrial facility in six water districts in West Virginia and Ohio.Serum samples and questionnaires, including residential history, were collected in 2005-2006. We modeled log serum PFOA (nanograms per milliliter) for current residents as a function of years of residence in a water district, adjusted for a variety of factors. We modeled the half-life in former residents who lived in two water districts with high exposure levels using a two-segment log-linear spline.We modeled serum PFOA concentration in 17,516 current residents as a function of years of residence (R2 = 0.68). Years of residence was significantly associated with PFOA concentration (1% increase in serum PFOA/year of residence), with significant heterogeneity by water district. Half-life was estimated in two water districts comprising a total of 1,573 individuals. For the participants included in our analyses, we found that years since residing in a water district was significantly associated with serum PFOA, which yielded half-lives of 2.9 and 8.5 years for water districts with higher and lower exposure levels, respectively.Years of residence in an exposed water district is positively associated with observed serum PFOA in 2005-2006. Differences in serum clearance rate between low- and high-exposure water districts suggest a possible concentration-dependent or time-dependent clearance process or inadequate adjustment for background exposures.

The C8 Health Project was established in 2005 to collect data on perfluorooctanoic acid (PFOA, or C8) and human health in Ohio and West Virginia communities contaminated by a fluoropolymer production facility.We assessed PFOA exposure via contaminated drinking water in a subset of C8 Health Project participants who drank water from private wells.Participants provided demographic information and residential, occupational, and medical histories. Laboratory analyses were conducted to determine serum-PFOA concentrations. PFOA data were collected from 2001 through 2005 from 62 private drinking water wells. We examined the relationship between drinking water and PFOA levels in serum using robust regression methods. As a comparison with regression models, we used a first-order, single-compartment pharmacokinetic model to estimate the serum:drinking-water concentration ratio at steady state.The median serum PFOA concentration in 108 study participants who used private wells was 75.7 μg/L, approximately 20 times greater than the levels in the U.S. general population but similar to those of local residents who drank public water. Each 1 μg/L increase in PFOA levels in drinking water was associated with an increase in serum concentrations of 141.5 μg/L (95% confidence interval, 134.9-148.1). The serum:drinking-water concentration ratio for the steady-state pharmacokinetic model was 114.PFOA-contaminated drinking water is a significant contributor to PFOA levels in serum in the study population. Regression methods and pharmacokinetic modeling produced similar estimates of the relationship.

Abstract High-density, non-thermal, glow-discharge atmospheric-pressure plasma was used for graft polymerization of a vapor deposited fluorocarbon mixture of 1,1,2,2-tetrahydroperfluorodecyl acrylate and 1,1,2,2-tetrahydroperlluorododecyl acrylate on undyed cotton fabrics, which furnished a [...]

Capillary gas chromatography was investigated as a method of analyzing and quantifying the products of the high-temperature gas-phase oxidation of hexafluoropropene. Standard polysiloxane polymer stationary phases were found to be ineffective in separating the aggressive mixture of oxyfluorocarbons and perfluorocarbons. Adsorbent type stationary phases provided better retention and separation for the exceedingly volatile components than polar/non-polar liquid phases. The tested silica--based porous--layer phase was found to be susceptible to degradation through interaction with acid fluoride species. The analysis was ultimately performed in two stages. Authentic oxidation product gas samples were first analyzed, then treated with aqueous potassium hydroxide to remove carbonyl compounds and resampled to determine oxygen content on the same system. Detector response factor ratios for a number of different perfluorocarbons were obtained, the information which is useful for chromatographic method development but is conspicuously absent in the open literature. The system was found to have good long-term stability with calibration deviations of less than 3% over a period of two years. Keywords: hexafluropropene, oxidation, capillary gas chromatography DOI: 10.1134/S1061934814010109, 2,2,3-Triiluoro-3-(triiluoromethyl)-oxirane (commonly known as hexafluoropropene oxide, HFPO), a versatile fluorochemical intermediate used in the manufacture of many high-grade organofluorine products, is prepared almost exclusively through the oxidation of hexafluoropropene (HFP). [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.04.012 Byline: A. Papageorgiou (a), J.R. Barton (b), A. Karagiannidis (a) Abbreviations: AEA, AEA Technology; AiIE, Associates in Industrial Ecology; APC, air pollution control; CHP, combined heat and power; CH.sub.4, methane; CO.sub.2, carbon dioxide; CO.sub.2-eq, carbon dioxide equivalents; DEFRA, Department for Environment Food and Rural Affairs; DOC, degradable organic carbon; DOC.sub.F, fraction DOC dissimilated; DTI, Department of Trade and Industry; EC, European Commission; EF, emission factor; EfW, energy from waste; ERM, Environmental Resources Management; FBI, fluidised bed incinerator; GCV, gross calorific value; GHG, greenhouse gas; GWP, global warming potential; HFCs, hydrofluorocarbons; IPCC, Intergovernmental panel on climate change; L.sub.0, methane generation potential; MBI, Mass Burn Incineration; MBT, mechanical biological treatment; MCF, methane correction factor; MHT, mechanical heat treatment; MSW, municipal solid waste; NCV, net calorific value; N.sub.2O, nitrous oxide; PFCs, perfluorocarbons; OX, oxidation factor; SNCR, selective non-catalytic reduction; SRF, solid recovered fuel; SF.sub.6, sulphur hexafluoride Abstract: Waste management activities contribute to global greenhouse gas emissions approximately by 4%. In particular the disposal of waste in landfills generates methane that has high global warming potential. Effective mitigation of greenhouse gas emissions is important and could provide environmental benefits and sustainable development, as well as reduce adverse impacts on public health. The European and UK waste policy force sustainable waste management and especially diversion from landfill, through reduction, reuse, recycling and composting, and recovery of value from waste. Energy from waste is a waste management option that could provide diversion from landfill and at the same time save a significant amount of greenhouse gas emissions, since it recovers energy from waste which usually replaces an equivalent amount of energy generated from fossil fuels. Energy from waste is a wide definition and includes technologies such as incineration of waste with energy recovery, or combustion of waste-derived fuels for energy production or advanced thermal treatment of waste with technologies such as gasification and pyrolysis, with energy recovery. The present study assessed the greenhouse gas emission impacts of three technologies that could be used for the treatment of Municipal Solid Waste in order to recover energy from it. These technologies are Mass Burn Incineration with energy recovery, Mechanical Biological Treatment via bio-drying and Mechanical Heat Treatment, which is a relatively new and uninvestigated method, compared to the other two. Mechanical Biological Treatment and Mechanical Heat Treatment can turn Municipal Solid Waste into Solid Recovered Fuel that could be combusted for energy production or replace other fuels in various industrial processes. The analysis showed that performance of these two technologies depends strongly on the final use of the produced fuel and they could produce GHG emissions savings only when there is end market for the fuel. On the other hand Mass Burn Incineration generates greenhouse gas emission savings when it recovers electricity and heat. Moreover the study found that the expected increase on the amount of Municipal Solid Waste treated for energy recovery in England by 2020 could save greenhouse gas emission, if certain Energy from Waste technologies would be applied, under certain conditions. Author Affiliation: (a) Laboratory of Heat Transfer and Environmental Engineering, Department of Mechanical Engineering, Box 483, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece (b) School of Civil Engineering, Faculty of Engineering, The University of Leeds, LS2 9JT Leeds, UK Article History: Received 7 August 2008; Revised 27 February 2009; Accepted 2 April 2009

The GAUSSIAN 96 program, GIAO-MP2 and IGLO methods were utilized to calculate the nuclear magnetic resonance (NMR) chemical shifts of fluorocarbocations. IGLO and GIAO-MP2 analysis of the 13C and 19F NMR chemical shifts of fluorocarbocations at the MP2/6-31G level indicated the correlation between NMR chemical shifts with the experimental data. Furthermore, analysis of the protocleavage of trifluoroacetic acids in superacids indicated the presence of a gitonic cation intermediate.

Convective boiling from small surfaces with submerged impingement of fluorocarbon liquid was studied for high-performance cooling systems of electronic devices. The local heat transfer coefficients from silicon heaters in submerged impingement were measured by two independent methods. One method was to regulate the distribution of the heater power to provide a uniform temperature. The other method employed was inverse analysis. Inverse analysis was utilized to correct the effect of heat conduction in the heater and to determine the distribution of heat transfer coefficients on the cooling surface.

A novel method for the synthesis of CF3C(O)OONO2 was developed based on the nitration of trifluoroperacetic acid which was formed from the reaction of (CF3C(O))2 with H2O2. Spectroscopic analysis of the resulting matrix-isolated CF3C(O)OONO2 indicated the presence of one rotamer and a molecular geometry that was similar to FC(O)OONO2. Furthermore, the trifluoroacetyl peroxynitrate was composed of CF2C(O)OO and O2NOO moieties that were arranged in a planar geometry.

A mirror-polishing technique for fluorocarbon polymer surfaces using high-precision diamond cutting tools was developed. The goal of this technique was the reduction of ultratrace elemental analysis contamination levels of containers fabricated from such mirror-polished materials. Remarkably smooth inner surfaces with degrees of flatness of 0.1 [[micro]meter] peak-to-valley (PTV) for containers fabricated from mirror-polished PTFE materials were obtained, in contrast to degrees of surface flatness of more than 30 [[micro]meter] PTV for commercially available PTFE containers. (Here, PTV denotes the difference between the highest peak and deepest valley in a scanned area of 10 x 10 [[micro]meter].) Extractable impurity levels for mirror-polished PTFE container surfaces were reduced by more than 1 order of magnitude relative to those of unpolished PTFE containers. The surface conditions of the PTFE containers were observed by atomic force and scanning electron microscopy. The microphotographs so obtained suggest that the degree of surface smoothness of the containers is proportional to their ultratrace metallic contamination levels.

The GAUSSIAN 96 program, GIAO-MP2 and IGLO methods were utilized to calculate the nuclear magnetic resonance (NMR) chemical shifts of fluorocarbocations. IGLO and GIAO-MP2 analysis of the 13C and 19F NMR chemical shifts of fluorocarbocations at the MP2/6-31G level indicated the correlation between NMR chemical shifts with the experimental data. Furthermore, analysis of the protocleavage of trifluoroacetic acids in superacids indicated the presence of a gitonic cation intermediate.

Fluoroacetate and subsequently 4-fluorothreonine are produced by Streptomyces cattleya after addition of the inorganic fluoride to the culture broth. Tracer experiments showed that the carbon skeleton of fluoroacetate is taken from C-1 and C-2 of glycerol through beta-hydroxypyruvate, whose hydroxyl group is replaced by fluoride.

Analysis of the bilayer behavior and the thermodynamics of a series of fluorocarbon/hydrocarbon amphiphiles reveals the driving force for the self-assembling behavior. Proper design of 'amphiphilic/amphiphobic' nature of the solute molecules leads to molecular assemblies. Cohesive energy difference between solute and solvent is the driving force for the molecular assembly, which is independent of the magnitude of the cohesive energy.

A method for the synthesis of RfI was developed based on the reaction of fluroolefins with iodine monochloride in anhydrous HF (AHF). The synthetic strategy involves the electrophilic iodofluorination of fluoroolefins that proceeded as a conjugate process that does not involve the formation of iodine monofluoride. The stepwise process also involves the protonation of iodine monochloride and the generation of a highly electrophilic halonium ion aggregate.

A method for the synthesis of RfI was developed based on the reaction of fluroolefins with iodine monochloride in anhydrous HF (AHF). The synthetic strategy involves the electrophilic iodofluorination of fluoroolefins that proceeded as a conjugate process that does not involve the formation of iodine monofluoride. The stepwise process also involves the protonation of iodine monochloride and the generation of a highly electrophilic halonium ion aggregate.

The hybrid thin films cast on silicon wafers are used for evaluating the intermolecular associations between a cationic lipid and two model polymers. The mechanical approach for immobilization of the antimicrobial dioctadecyldimethylammonium bromide (DODAB) lipid in a polymeric network has represented a major improvement regarding its applications to produce antimicrobial coatings.

The conclusions regarding both the kinetics of film fluorination and the effect of fluorocarbon groups on film properties are developed by the dynamics of the acylation of poly(hydroxyethyl methacrylate) (PHEMA), with fluorinated acid chlorides. The methods for controlling the time of exposure for PHEMA films with the fluorinated acid chlorides are explained using these film propertie

A mixed Si:C layer forms at the surface when simulations of silicon surfaces are exposed to C and F containing radicals and Ar(super +) ions at 200eV. It is concluded that the a-Si:C layer could be the principal factor reducing the etch rate of Si surfaces in the presence of fluorocarbon (FC) plasma.

The mechanisms of carbon-fluorine bond activation in various substrates by Cp(sub 2)(super *)ZrH2 are studied for a variety of flurocarbon substrates. The regiochemistry of the exchange is related with the strong asymmetric charge distribution in the perfluoropropene olefin.

The evolution of etches products and etched surface of Si and SiO2 bombarded with 50-400 eV ion beams of CF (sub 3)(super +1) and CF (sub 2)(super +1) are presented. Observations suggest that the initial etching rate of the clean Si surface is rather high but soon decreases at higher fluences due to the growth of a fluorocarbon mixing layer on the surface.

An investigation on the surface-induced and electron-induced chemistry of trifluoroidomethane (CF3I), a potential replacement for chlorofluorocarbons (CFCs) and chlorofluorobromocarbons (halons) was carried out under ultrahigh vacuum conditions (p~1x10(super -10) Torr) on Mo (110). The investigation revealed that dissociative adsorption of CF3I leads only to nonselective decomposition on Mo (110), in contrast to reactions of CF3I on other metal surfaces.

The mass-selected 5-200 eV C(sub 3)F(sub 5)(super +) and C(sub 2)F(sub 5)(super +) ion beams are used to form nanometer thick fluorocarbon and Si(sub x)C(sub y)F(sub z) films on H-Si(100). The average elemental and chemical content of the deposited film is independent of ion identity and kinetic energy.

The retention properties of eight alkyl, aromatic, and fluorinated reversed-phase high-performance liquid chromatography bonded phases were characterized through the use of linear solvation energy relationships (LSERs). The stationary phases were investigated in a series of methanol/water mobile phases. LSER results show that solute molecular size and hydrogen bond acceptor basicity under all conditions are the two dominant retention controlling factors and that these two factors are linearly correlated when either different stationary phases at a fixed mobile-phase composition or different mobile-phase compositions at a fixed stationary phase are considered. The large variation in the dependence of retention on solute molecular volume as only the stationary phase is changed indicates that the dispersive interactions between nonpolar solutes and the stationary phase are quite significant relative to the energy of the mobile-phase cavity formation process. PCA results indicate that one PCA factor is required to explain the data when stationary phases of the same chemical nature (alkyl, aromatic, and fluoroalkyl phases) are individually considered. However, three PCA factors are not quite sufficient to explain the whole data set for the three classes of stationary phases. Despite this, the average standard deviation obtained by the use of these principal component factors are significantly smaller than the average standard deviation obtained by the LSER approach. In addition, selectivities predicted through the LSER equation are not in complete agreement with experimental results. These results show that the LSER model does not properly account for all molecular interactions involved in RP-HPLC. The failure could reside in the [V.sub.2] solute parameter used to account for both dispersive and cohesive interactions since 'shape selectivity' predictions for a pair of structural isomers are very bad.