Abstract  This work examines the mass spectra of several environmentally relevant amides, perfluorooctanesulfonamide (FOSA), NMeFOSA, NEtFOSA, and NMe(2)FOSA, under electron ionization conditions. A previous mass spectral study of FOSA and NEtFOSA led the authors to propose possible structures for some of the fragment ions and fragmentation pathways that might explain their formation. In the present communication, further fragment ions are identified for these two compounds and alternative fragmentation pathways proposed. Mass spectral analyses of NMeFOSA and NMe(2)FOSA and of mass-labeled NMeFOSA and NEtFOSA reinforce our conclusions about potential fragmentation pathways for these amides and the fragment ions expected. The mass spectral data presented here will help chemists to identify signals found in a gas chromatographic/mass spectrometric (GC/MS) analysis that stem from these perfluoroalkylsulfonamides.

Abstract  The formation of amyloid-β peptide (Aβ) oligomers at the cellular membrane is considered to be a crucial process underlying neurotoxicity in Alzheimer's disease (AD). Therefore, it is critical to characterize the oligomers that form within a membrane environment. To contribute to this characterization, we have applied strategies widely used to examine the structure of membrane proteins to study the two major Aβ variants, Aβ40 and Aβ42. Accordingly, various types of detergent micelles were extensively screened to identify one that preserved the properties of Aβ in lipid environments-namely the formation of oligomers that function as pores. Remarkably, under the optimized detergent micelle conditions, Aβ40 and Aβ42 showed different behavior. Aβ40 aggregated into amyloid fibrils, whereas Aβ42 assembled into oligomers that inserted into lipid bilayers as well-defined pores and adopted a specific structure with characteristics of a β-barrel arrangement that we named β-barrel pore-forming Aβ42 oligomers (βPFOsAβ42). Because Aβ42, relative to Aβ40, has a more prominent role in AD, the higher propensity of Aβ42 to form βPFOs constitutes an indication of their relevance in AD. Moreover, because βPFOsAβ42 adopt a specific structure, this property offers an unprecedented opportunity for testing a hypothesis regarding the involvement of βPFOs and, more generally, membrane-associated Aβ oligomers in AD.

Abstract  The gas chromatographic behaviors of two neutral hydrophobic perfluorooctanesulfonamide compounds, such as perfluorooctanesulfonamide (PFOSA) and N-ethyl perfluorooctanesulfonamide (N-EtPFOSA) were studied on DB-1701 and DB-5ms column. The analysis results revealed that low detection limit, good peak shape and good separability of two perfluorooctanesulfonamide compounds could be obtained on DB-1701 column.

Abstract  A solid phase extraction-liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS) analytical method for the analysis of perfluorinated compounds (PFCs) in water is presented. The method incorporates a stable isotope internal standard (IS) for each target analyte added prior to sample collection. Method validation for perfluorinated carboxylic acids (PFCAs) (C4-C12), perfluorinated sulfonic acids (PFSAs) (C4, C6, and C8), and perfluorooctane sulfonamide (PFOSA) in laboratory Milli Q water evaluated the following: (1) method accuracy and precision over the concentration range 0.025 ng mL(-1) to 25 ng mL(-1); (2) internal standard calibration; (3) quantitation of mixed branched and linear isomers of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) with linear isomer calibration; (4) method minimum reporting levels (MRLs) (Shoemaker et al, http://www.epa.gov/nerlcwww/Method%20537_FINAL_rev1.1.pdf, and Winslow et al, Environ. Sci. Technol., 2006, 40, 281-288); and (5) 28 day holding time at the MRL, low, and mid range of the calibration range. IS calibration with IS addition to the sample bottle prior to sample collection demonstrated an overall method accuracy of at least 100 +/- 10% with a precision of +/- 15% and a 28-day sample holding time at the MRLs for all target analytes. Method application to groundwater, production facility non-contact cooling water, and production facility wastewater treatment effluent samples demonstrated a method accuracy of at least 100 +/- 19% with a precision of +/- 25% for all target analytes.

Abstract  Transport and fate of perfluoro- and polyfluoroalkyl substances (PFASs) in an urban water body that receives mainly urban runoff was investigated. Water, suspended solids, and sediment samples were collected during the monsoon (wet) and inter-monsoon (dry) season at different sites and depths. Samples were analyzed for C7 to C12 perfluoroalkyl carboxylate homologues (PFCAs) (PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA), perfluorohexane, perfluorooctane, and 6:2-fluorotelomer sulfonate (PFHxS, PFOS, and 6:2FtS, respectively), perfluorooctane sulfonamide (FOSA), N-ethyl FOSA (sulfluramid), N-ethyl sulfonamidoethanol (N-EtFOSE), and N-methyl and N-ethyl sulfonamidoacetic acid (N-EtFOSAA and N-MeFOSAA, respectively). Concentrations in wet samples were only slightly higher. The sum total PFAS (ΣPFAS) concentrations dissolved in the aqueous phase and sorbed to suspended solids (SS) ranged from 107 to 253 ng/L and 11 to 158 ng/L, respectively. PFOA, PFOS, PFNA, PFHxS, and PFDA contributed most (approximately 90 %) to the dissolved ΣPFASs. N-EtFOSA dominated the particulate PFAS burden in wet samples. K D values of PFOA and PFOS calculated from paired SS and water concentrations varied widely (1.4 to 13.7 and 1.9 to 98.9 for PFOA and PFOS, respectively). Field derived K D was significantly higher than laboratory K D suggesting hydrophobic PFASs sorbed to SS resist desorption. The ΣPFAS concentrations in the top sedimentary layer ranged from 8 to 42 μg/kg and indicated preferential accumulation of the strongly sorbing long-chain PFASs. The occurrence of the metabolites N-MeFOSAA, N-EtFOSAA and FOSA in the water column and sediments may have resulted from biological or photochemical transformations of perfluorooctane sulfonamide precursors while the absence of FOSA, N-EtFOSA and 6:2FtS in sediments was consistent with biotransformation.

Abstract  Perfluorooctane sulfonate (PFOS) has been reported to be among the most concentrated persistent organic pollutants in Arctic marine wildlife. The present study examined the in vitro depletion of major PFOS precursors, N-ethyl-perfluorooctane sulfonamide (N-EtFOSA) and perfluorooctane sulfonamide (FOSA), as well as metabolite formation using an assay based on enzymatically viable liver microsomes for three top Arctic marine mammalian predators, polar bear (Ursus maritimus), beluga whale (Delphinapterus leucas), and ringed seal (Pusa hispida), and in laboratory rat (Rattus rattus) serving as a general mammalian model and positive control. Rat assays showed that N-EtFOSA (38 nM or 150 ng mL(-1)) to FOSA metabolism was >90% complete after 10 min, and at a rate of 23 pmol min(-1) mg(-1) protein. Examining all species in a full 90 min incubation assay, there was >95% N-EtFOSA depletion for the rat active control and polar bear microsomes, similar to 65% for ringed seals, and negligible depletion of N-EtFOSA for beluga whale. Concomitantly, the corresponding in vitro formation of FOSA from N-EtFOSA was also quantitatively rat approximate to polar bear > ringed seal >>> beluga whale. A lack of enzymatic ability and/or a rate too slow to be detected likely explains the lack of N-EtFOSA to FOSA transformation for beluga whale. In the same assays, the depletion of the FOSA metabolite was insignificant (p > 0.01) and with no concomitant formation of PFOS metabolite. This suggests that, in part, a source of FOSA is the biotransformation of accumulated N-EtFOSA in free-ranging Arctic ringed seal and polar bear.

Abstract  Perfluorinated acids and their salts have emerged as an important class of global environmental contaminants. Biological monitoring surveys conducted using tissues of marine organisms reported the occurrence of perfluorooctanesulfonate (PFOS) and related perfluorinated compounds in biota from various seas and oceans, including the Arctic and the Antarctic Oceans. Occurrence of perfluorinated compounds in remote marine locations is of concern and indicates the need for studies to trace sources and pathways of these compounds to the oceans. Determination of sub-parts-per-trillion (ng/L) or parts-per-quadrillion (pg/L) concentrations of aqueous media has been impeded by relatively high background levels arising from procedural or instrumental blanks. Our research group has developed a reliable and highly sensitive analytical method by which to monitor perfluorinated compounds in oceanic waters. The method developed is capable of detecting PFOS, perfluorohexanesulfonate (PFHS), perfluorobutanesulfonate (PFBS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorooctanesulfonamide (PFOSA) at a few pg/L in oceanic waters. The method was applied to seawater samples collected during several international research cruises undertaken during 2002-2004 in the central to eastern Pacific Ocean (19 locations), South China Sea and Sulu Seas (five), north and mid Atlantic Ocean (12), and the Labrador Sea (20). An additional 50 samples of coastal seawater from several Asian countries (Japan, China, Korea) were analyzed. PFOA was found at levels ranging from several thousands of pg/L in water samples collected from coastal areas in Japan to a few tens of pg/L in the central Pacific Ocean. PFOA was the major contaminant detected in oceanic waters, followed by PFOS. Further studies are being conducted to elucidate the distribution and fate of perfluorinated acids in oceans.

Abstract  Temporal, biological, and environmental factors affecting accumulation of perfluoroalkyl substances (PFASs) are poorly understood in comparison with legacy lipid-soluble persistent organic pollutants. Temporal and biological comparisons of PFAS concentrations were made in great skuas (Stercorarius skua), a marine apex predator. Concentrations of 16 PFASs were quantified, including C4-C10 perfluorosulfonates (PFSAs), perfluorooctanesulfonamide (PFOSA), and C5-C14 perfluorocarboxylates (PFCAs). Concentrations of PFASs (ng/g wet wt) were significantly higher in eggs collected in Shetland in 2008 compared with 1980 for most compounds. However, the magnitude of the differences was small, with a mean increase of 3 ng/g. Levels of PFASs in great skuas were low compared with those of other seabirds in similar ecological niches; and in contrast to other contaminants measured in the same eggs, concentrations of PFASs did not correlate with trophic level. Concentrations of PFASs in adult plasma were significantly higher in males than in females for most PFASs. This suggests that maternal transfer through egg laying may be a significant mode of elimination of PFASs in female great skuas. The low concentrations of PFASs in eggs and plasma compared with other halogenated organic contaminants and other species suggest that great skuas do not bioaccumulate PFASs to the same extent as some other seabirds.

Abstract  Perfluorochemicals (PFCs) are used in numerous applications, mainly as surfactants, and occur ubiquitously in the environment as complex mixtures. This study was undertaken to characterize the occurrence and sources of commonly detected PFC compounds in surface waters of the Marina catchment, a watershed that drains an urbanized section of Singapore. Of the 19 target PFCs, 13 were detected with perfluorooctanoic acid (PFOA) (5-31 ng L(-1)) and perfluorooctane sulfonate (PFOS) (1-156 ng L(-1)) being the dominant components. Other compounds detected included perfluoroalkyl carboxylates (C7-C12) and perfluoroalkyl sulfonates (C6 and C8). Sulfonamide compounds detected 2-(N-ethylperfluorooctanesulfonamido) acetic acid (N-EtFOSAA), 2-(N-methylperfluorooctanesulfonamido) acetic acid (N-MeFOSAA), perfluorooctanesulfonamido acetic acid (FOSAA) and perfluorooctanesulfonamide (FOSA) were putative transformation products of N-EtFOSE and N-MeFOSE, the N-ethylated and N-methylated ethyl alcohol derivatives, respectively. Surface water concentrations were generally higher during dry weather than during storm water flow: the median concentrations of total PFCs in dry and wet weather were 57 and 138 ng L(-1) compared to 42 and 79 ng L(-1), respectively, at Stamford and Alexandra canal, suggesting the presence of a continuous source(s) which is subject to dilution during storm events. In rain water, median concentrations were 6.4 ng L(-1), suggesting rain contributed from 12-25% to the total PFC load for non-point source sites. The longitudinal concentration profile along one of the canals revealed a point source of sulfonated PFCs (PFOS), believed to originate from aqueous film-forming foam (AFFF). Sources were characterized using principal component analysis (PCA) and by plotting PFHxS/PFOA against PFOS/PFOA. Typical surface waters exhibit PFOS/PFOA and PFHxS/PFOA ratios below 0.9 and 0.5, respectively. PCA plots reveal waters impacted by "non-typical" PFC sources in Alexandra canal.

Abstract  The widespread occurrence and environmental persistence of perfluorinated compounds (PFCs) received worldwide attention recently. Exhaustive analysis of all fluorinated compounds in an environmental sample can be daunting because of the constraints in the availability of analytical standards and extraction methods. Combustion ion chromatographic technique for trace fluorine analysis was used to assess the concentrations of known PFCs (e.g., PFOS, PFOA) and total fluorine (TF) in the blood of wild rats collected from Japan. The technique was further validated using tissues from PFOA-exposed rats. Six PFCs (PFOS, PFOSA, PFUnDA, PFDA, PFNA, and PFOA) were detected in all of the wild rat blood samples. Concentrations of extractable organic fluorine (EOF) in fraction 1 (Fr1; MTBE extraction) of wild rats ranged 60.9-134 ng F mL(-1), while those in fraction 2 (Fr2; hexane) were below LOQ (32 ng F mL(-1)); TF concentrations in the blood of wild rats ranged from 59.9-192 ng F mL(-1). The contribution of known PFCs in EOF-Fr1 (MTBE) varied from 9% to 89% (56% on average), and known PFC concentrations in TF content were less than 25%. In contrast, TF concentrations in the blood of PFOA-exposed rats ranged from 46900 to 111,000 ng F mL(-1), with PFOA contributing over 90% of TF. A comparison of results from the samples analyzed in this study and the literature revealed three distinct groups with PFOA/known PFC and TF levels (i.e., wild rats and general population, occupationally exposed workers, and PFOA-exposed laboratory rats). The mass balance analysis of the different forms of fluorine in blood suggested the presence of other forms of organic fluorine in addition to known PFCs.

Abstract  A method for the analysis of airborne (semi-)volatile polyfluorinated alkyl substances (PFASs) was optimized to avoid solvent-induced response enhancements as observed using ethyl acetate as extraction solvent (recoveries up to 300%, likely due to acetic acid as impurity). Of nine solvents tested, only the use of acetone, dichloromethane, methyl tert-butyl ether, and acetone:petroleum ether (1:1, v/v) resulted in recoveries below 100% and acetone:methyl tert-butyl ether (1:1, v/v) was chosen as suited extraction solvent. An appropriate GC capillary column and the application of mass-labelled internal standards appeared to be essential for these analyses. Instrumental limits of detection of <0.2 pg (dimethylperfluoroocatanesulfonamide, ethyl-[(2)H(5)]perfluorooctanesulfonamide, methyl-[(2)H(3)]perfluorooctanesulfonamide) to 8.2 pg (perfluorooctanesulfonamide) and LOQ of 0.4 pg (dimethylperfluoroocatanesulfonamide, ethyl-[(2)H(5)]perfluorooctanesulfonamide, methyl-[(2)H(3)]perfluorooctanesulfonamide) to 16.4 pg (perfluorooctanesulfonamide) were determined.

Abstract  Perfluoroalkyl acids (PFAAs) are anthropogenic chemicals that occur in snow from both remote and source regions. Experiments were conducted to determine how PFAAs are released from a melting snowpack. Different PFAAs eluted from the snowpack at different times, those with short chains eluting early, those with long chains eluting late. The concentrations in the meltwater of PFAAs with medium chain lengths of 6 to 9 perfluorinated carbon atoms first increased and then decreased during the melt period. Such a peak elution had not been previously observed for any other chemicals. The specific snow surface area (SSA) influenced this elution type, with peak concentrations occurring earlier in a snowpack with lower SSA. Model simulations suggested that the snow surface decrease during the melt alone was insufficient to explain the observations. It was ruled out that the calcium concentration affected PFAA sorption to the snow surface in a similar way as sorption to sediments. Adsorption coefficients of PFAAs to the snow surface were estimated by fitting the measured and modeled elution profiles.

Abstract  Per- and polyfluoroalkyl substances (PFASs) are a class of compounds with unique chemical properties that have been shown useful in a wide variety of applications because they provide materials with reduced surface tension and exceptional non-stick properties. PFASs are commonly found in impregnation materials, coatings of papers and textiles, fire-fighting foams, pesticides, and cleaning agents. The potential for human exposure to PFASs is high because of their widespread distribution. The aim of this study was to investigate levels of PFASs in men and women from Sweden and to assess the influence of gender and parity among women. Levels of 13 PFASs were determined in plasma samples collected during 2001-2004 from 1016 (507 women) 70year-old participants from the population-based Prospective Study of the Vasculature in Uppsala Seniors (PIVUS). The PFASs studied were nine perfluorinated carboxylic acids (PFCAs), four perfluorinated sulfonic acids (PFSAs) and perfluorooctane sulfonamide (PFOSA). In addition, structural isomers of perfluorooctane sulfonic acid (PFOS) were determined in a subset of 398 individuals. The detection rates were high and the majority of the studied compounds were detected in more than 75% of the participants. Levels of the selected analytes were found to be similar to other studies of non-occupationally exposed populations. Gender differences were observed in levels of PFHpA which was higher in men, while PFHxS was higher in women. Parity among women was shown to have a minor effect on PFAS concentrations and we found primi- and multiparous women to have slightly lower levels of PFUnDA when compared to nulliparous women.

Abstract  The continuous production and use in certain parts of the world of perfluoroalkyl sulfonamide derivatives that can degrade to perfluorooctane sulfonic acid (PFOS) has called for better understanding of the environmental fate of these PFOS precursors. Aerobic soil biotransformation of N-ethyl perfluorooctane sulfonamide (EtFOSA, also known as Sulfluramid) was quantitatively investigated in semi-closed soil microcosms over 182 d for the first time. The apparent soil half-life of EtFOSA was 13.9±2.1 d and the yield to PFOS by the end of incubation was 4.0 mol%. A positive identification of a previously suspected degradation product, EtFOSA alcohol, provided strong evidence to determine degradation pathways. The lower mass balance in sterile soil than live soil suggested likely strong irreversible sorption of EtFOSA to the test soil. The aerobic soil biotransformation of a technical grade N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE) was semi-quantitatively examined, and the degradation pathways largely followed those in activated sludge and marine sediments. Aside from PFOS, major degradation products included N-Ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA), perfluorooctane sulfonamide (FOSA) and perfluorooctane sulfonamide acetic acid (FOSAA). This study confirms that aerobic soil biotransformation of EtFOSE and EtFOSA contributes significantly to the PFOS observed in soil environment, as well as to several highly persistent sulfonamide derivatives frequently detected in biosolid-amended soils and landfill leachates.

Abstract  Objective: We established a method of UPLC-MS/MS that was to detect fifteen precursors of perfluoroalkyl sulfonates (PFSA) and perfluoroalkyl carboxylates (PFCA) in serum. Methods: Briefly, TBAS solution was added to sera, then the mixed solution was extracted with aliquots of MTBE. The MTBE aliquots were combined, evaporated to dryness under nitrogen, and reconsituted in 0.25 ml of methanol and water (1:1). Then the reconstituted solution through 0.2 µm nylon syringe filter was collected. Chromatographic separation was performed using a Waters ACQUITY (TM) BEH ¹⁸C column (50 mm × 2.1 mm × 1.7 mm). Analyte quantitation was performed in the negative electrospray ionization mode and multiple reaction monitoring (MRM). Results: Three target substances, 6: 6PFPi, 6: 8PFPi, 8: 8PFPi, were externally confirmed by standard addition. Rates of recovery for these three chemicals were from 41.01% to 112.13% in two standard levels. And the relative standard deviations (RSD) were lower than 11.63% and higher than 1.80%. The other twelve substances were quantified with internal standard. Moreover in two standard levels, rate of recovery for these chemicals ranged from 70.25% to 127.51%. And RSD were more than 1.23% and less than 15.45%. And the corresponding limit of detection (LOD) and limit of quantitation (LOQ) for all target substances were 0.1-5.0 pg/ml and 0.2-10.0 pg/ml. Then we detected these target substances in ten different human serum samples. The levels of few substances were higher than LOD. And the ranges of FOSA-M, N-EtFOSA-M, N-MeFOSAA, N-EtFOSAA were respectively < LOD-0.94 pg/ml, < LOD-10.08 pg/ml, < LOD-6.74 pg/ml, < LOD-1.04 pg/ml. Conclusion: The method, with high sensitivity and accuracy, could meet the actual testing requirements.

Abstract  To improve understanding of long-range transport of perfluoroalkyl substances to the High Arctic, samples were collected from a snow pit on the Devon Ice Cap in spring 2008. Snow was analyzed for perfluoroalkyl acids (PFAAs), including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs), as well as perfluorooctane sulfonamide (FOSA). PFAAs were detected in all samples dated from 1993 to 2007. PFAA fluxes ranged from <1 to hundreds of ng per m(2) per year. Flux ratios of even-odd PFCA homologues were mostly between 0.5 and 2, corresponding to molar ratios expected from atmospheric oxidation of fluorotelomer compounds. Concentrations of perfluorobutanoic acid (PFBA) were much higher than other PFCAs, suggesting PFBA loading on the Devon Ice Cap is influenced by additional sources, such as the oxidation of heat transfer fluids. All PFCA fluxes increased with time, while PFSA fluxes generally decreased with time. No correlations were observed between PFAAs and the marine aerosol tracer, sodium. Perfluoro-4-ethylcyclohexanesulfonate (PFECHS) was detected for the first time in an atmospherically - derived sample, and its presence may be attributed to aircraft hydraulic system leakage. Observations of PFAAs from these samples provide further evidence that atmospheric oxidation of volatile precursors is an important source of PFAAs to the Arctic environment.

Abstract  Per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), are ubiquitous in the environment. Investigations into their fate and potential phase-partitioning behavior require separating solid from aqueous phases via filtration. However, sorption of aqueous-phase PFASs on filtration media may lead to underestimation of PFAS concentrations in the aqueous phase. The authors investigated the sorption of perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids (PFPiAs), polyfluoroalkyl phosphate monoesters, polyfluoroalkyl phosphate diesters (diPAPs), fluorotelomer sulfonates, and perfluorooctane sulfonamide on filtration media. The effects of concentration (3 spiking levels), filter media (4 types), matrix (4 matrices), and compound structure on sorption are reported. Glass fiber filtration resulted in the least sorption, whereas polytetrafluoroethylene filters resulted in the most sorption (up to 98%). Analyte concentration had no significant effect. Sorption was generally consistent across matrix types except for samples affected by aqueous film forming foam deployment, which displayed high sorption of PFOS on nylon filters. Sorption usually increased with an increasing number of carbon or fluorine atoms and was most pronounced for PFPiAs and diPAPs (30–75% sorption). Overall, glass fiber filters are more recommended than nylon filters in environmental samples when phase separation is required. Use of filtration media for PFAS must be preceded by matrix-specific testing to account for unpredictable effects.

Abstract  Investigations into the biodegradation potential of perfluorooctane sulfonate (PFOS)-precursor candidates have focused on low molecular weight substances (e.g., N-ethyl perfluorooctane sulfonamido ethanol (EtFOSE)) in wastewater treatment plant sludge. Few data are available on PFOS-precursor biodegradation in other environmental compartments, and nothing is known about the stability of high-molecular-weight perfluorooctane sulfonamide-based substances such as the EtFOSE-based phosphate diester (SAmPAP diester) in any environmental compartment. In the present work, the biodegradation potential of SAmPAP diester and EtFOSE by bacteria in marine sediments was evaluated over 120 days at 4 and 25 °C. At both temperatures, EtFOSE was transformed to a suite of products, including N-ethyl perfluorooctane sulfonamidoacetate, perfluorooctane sulfonamidoacetate, N-ethyl perfluorooctane sulfonamide, perfluorooctane sulfonamide, and perfluorooctane sulfonate. Transformation was significantly more rapid at 25 °C (t(1/2) = 44 ± 3.4 days; error represents standard error of the mean (SEM)) compared to 4 °C (t(1/2) = 160 ± 17 days), but much longer than previous biodegradation studies involving EtFOSE in sludge (t(1/2) ∼0.7-4.2 days). In contrast, SAmPAP diester was highly recalcitrant to microbial degradation, with negligible loss and/or associated product formation observed after 120 days at both temperatures, and an estimated half-life of >380 days at 25 °C (estimated using the lower bounds 95% confidence interval of the slope). We hypothesize that the hydrophobicity of SAmPAP diester reduces its bioavailability, thus limiting biotransformation by bacteria in sediments. The lengthy biodegradation half-life of EtFOSE and recalcitrant nature of SAmPAP diester in part explains the elevated concentrations of PFOS-precursors observed in urban marine sediments from Canada, Japan, and the U.S, over a decade after phase-out of their production and commercial application in these countries.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Rats were fed either nonfortified, ground rodent feed or feed fortified with 75 mg of sulfluramid/kg of feed for 56 days and then were fed the nonfortified diet for an additional 35 days. Samples from nine tissues and blood samples were collected and analyzed by gas chromatography. No overt clinical signs of toxicity were observed during the study except for a significant decrease in body weight gained in the treated group compared to the controls. This difference appeared to result from a significant reduction in rate of weight gain during the first 2 weeks of treatment. Diet consumption was not significantly different for treated and control groups. There were no detectable levels of sulfluramid present in tissue or blood samples during the study, but its metabolite, deethylsulfluramid, was present, and changes in its concentration were associated with first-order elimination kinetics. The blood half-life of 10.8 days was greater than those for the solid tissues. The

Abstract  BIOSIS COPYRIGHT: BIOL ABS. A method is described for estimating oral toxicities (mug/g) of slow-acting toxicants against subterranean termites, Coptotermes formosanus Shiraki and Reticulitermes flavipes (Kollar). Groups of termites were fed with a known amount of medium containing a dye marker and a toxicant. Marked termites were evaluated for daily mortality after total consumption of the medium. Toxicant doses ingested by termites were derived from the total amount of toxicant in the feeding medium and the biomass of termites engaged in that feeding. Using oral LD50 estimates in mug/g, the total amount of toxicant required to control a field colony can be projected.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM RESEARCH ARTICLE LINEPITHEMA-HUMILE SULFURAMIDE HYDRAMETHYLNON INSECTICIDE HOUSEHOLD PEST

Abstract  Copolymers composed of acrylamide (AM), N,N-dimethylacrylamide (DMAM), N-isopropylacrylamide (NIPAM) and 2-(N-ethyl-perfluorooctanesulfonamido) acrylamide (FOSA) were synthesized by free radical polymerization. The chemical structure of the resulting polymers was characterized with NMR spectroscopy and thermal properties were measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). H-1-NMR spectra of the copolymers of NIPAM with FOSA showed that FOSA was incorporated quantitatively. The glass transition temperature (T-g) of the copolymers and the terpolymers decreased with increasing FOSA content. The T(g)s, however, were higher than predicted for a random copolymer by the Fox equation, which was attributed to microphase separation of the hydrophobic, fluorinated species. Copolymers of AM and FOSA became discolored above 180 degrees C due to formation of cyclic imide and nitrile moieties through cyclization or dehydration of amide groups. The equilibrium water sorption of the copolymers decreased with increasing FOSA content, but increasing FOSA suppressed the water desorption kinetics. Water sorption and thermal stability were improved by terpolymerization of AM, NIPAM, DMAM and FOSA.

Abstract  Hydrophobically modified (HM) associating water-soluble poly(N,N-dimethylacrylamide) (PDMA) polymers were prepared by free-radical copolymerizations of DMA and 2-(N-ethylperfluoro-octanesulfonamido)ethyl acrylate (FOSA). The polymerizations were carried out in deionized water in the presence of ammonium persulfate at 50 degrees C or in bulk in the presence of AIBN at 65 degrees C. The copolymerization kinetics monitored simultaneously by F-19 and H-1 NMR spectroscopy indicates that DMA and FOSA is incorporated at the same relative rates throughout the polymerization. The viscosities of the polymer solutions were measured on a Brookfield viscometer and an Ubbelohde capillary viscometer. A large viscosity enhancement was observed in comparison with PDMA homopolymer solutions. The effects of polymer concentration, shear rate, surfactants, salts, and temperatures on the reduced and Brookfield viscosities were investigated. Interestingly, the aqueous solution of the copolymer prepared in bulk exhibits both hydrophobic interaction and polyelectrolyte effects in the presence of anionic perfluorocarbon surfactant. The resulting polymers were also characterized by size exclusion chromatography and by H-1 and F-19 NMR spectroscopy.