Abstract  Eleven perfluorinated alkyl acids (PFAAs) were analyzed in plasma from a total of 600 American Red Cross adult blood donors from six locations in 2010. The samples were extracted by protein precipitation and quantified by using liquid chromatography tandem mass spectrometry (HPLC/MS/MS). The anions of the three perfluorosulfonic acids measured were perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS). The anions of the eight perfluorocarboxylic acids were perfluoropentanoate (PFPeA), perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnA), and perfluorododecanoate (PFDoA). Findings were compared to results from different donor samples analyzed at the same locations collected in 2000-2001 (N = 645 serum samples) and 2006 (N = 600 plasma samples). Most measurements in 2010 were less than the lower limit of quantitation for PFBS, PFPeA, PFHxA, and PFDoA. For the remaining analytes, the geometric mean concentrations (ng/mL) in 2000-2001, 2006, and 2010 were, respectively, PFHxS: (2.25, 1.52, 1.34); PFOS (34.9, 14.5, 8.3); PFHpA (0.13, 0.09, 0.05); PFOA (4.70, 3.44, 2.44); PFNA (0.57, 0.97, 0.83); PFDA (0.16, 0.34, 0.27), and PFUnA (0.10, 0.18, 0.14). The percentage decline (parentheses) in geometric mean concentrations from 2000-2001 to 2010 were PFHxS (40%), PFOS (76%), and PFOA (48%). The decline in PFOS suggested a population halving time of 4.3 years. This estimate is comparable to the geometric mean serum elimination half-life of 4.8 years reported in individuals. This similarity supports the conclusion that the dominant PFOS-related exposures to humans in the United States were greatly mitigated during the phase-out period.

Abstract  Perfluorooctanoic acid (PFOA) is an emerging environmental pollutant attracting significant attention due to its global distribution, high persistence, and bioaccumulation properties. In this study, the degradation of aqueous PFOA at different temperatures was examined using heat-activated persulfate. Using this approach, 93.5% of PFOA was degraded after 30 h at 85 degrees C with 43.6% of F- yield, and the shorter chain length compounds (PFHpA (C6F13COOH), PFHxA (C5F11COOH), PFPeA (C4F9COOH), and PFBA (C3F2COOH)) were observed as degradation intermediates. The sequential degradation mechanism of losing one CF2 unit from PFOA and its intermediates on a step-by-step basis were observed. Controlled temperature kinetics studies yielded an activation energy of approximately 60 kJ/mol for the degradation of PFOA by heat-activated persulfate. However, at elevated temperatures, excess persulfate is needed for efficient PFOA degradation, presumably due to more intensive SO4 center dot- scavenging. Lower reaction pH was generally found to inhibit PFOA degradation, presumably due to the more prevalent radical-to-radical interactions. (C) 2011 Elsevier B.V. All rights reserved.

Abstract  Perfluoroalkyl acids (PFAAs) are globally found in various media, including food and especially fishery products. In the present study, the dietary exposure to 15 perfluoroalkyl acids was assessed for 3 French adult populations, namely high seafood consumers, high freshwater fish consumers, and pregnant women. Purified food extracts were analysed by LC-MS/MS and PFBA, PFPA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFTrDA, PFTeDA, PFBS, PFHxS, PFHpS, PFOS and PFDS were monitored and quantified according to the isotope dilution principle. Under lower bound (LB) hypothesis (i.e. contamination values<LOD considered as 0), high freshwater fish consumers appear as the most exposed to PFOS (7.5ng.kg(-1) bw.d(-1)), PFUnA (1.3ng.kg(-1) bw.d(-1)), PFDA (0.4ng.kg(-1) bw.d(-1)) and PFHpS (0.03ng.kg(-1) bw.d(-1)) while high seafood consumers appear as the most exposed to PFOA (1.2ng.kg(-1) bw.d(-1)), PFNA (0.2ng.kg(-1) bw.d(-1)) and PFHxS (0.06ng.kg(-1) bw.d(-1)). For all considered populations, the major exposure contributors are fish, seafood and water under LB hypothesis, while dairy products, bread and crispbread are the main contributors under upper bound (UB) hypothesis. Besides this food exposure assessment, further studies are needed to assess the more global PFAA exposure, taking into account indoor and outdoor air, dust and cutaneous contact, which could be other important contributors for this particular class of chemicals.

Abstract  Interactions of perfluoroalkyl acids (PFAAs) with tissue and serum proteins likely contribute to their tissue distribution and bioaccumulation patterns. Protein-water distribution coefficients (K(PW) ) based on ligand associations with bovine serum albumin (BSA) as a model protein were recently proposed as biologically relevant parameters to describe the environmental behavior of PFAAs, yet empirical data on such protein binding behavior are limited. In the present study, associations of perfluoroalkyl carboxylates (PFCAs) with two to 12 carbons (C₂-C₁₂) and perfluoroalkyl sulfonates with four to eight carbons (C₄, C₆, and C₈) with BSA are evaluated at low PFAA:albumin mole ratios and various solution conditions using equilibrium dialysis, nanoelectrospray ionization mass spectrometry, and fluorescence spectroscopy. Log K(PW) values for C₄ to C₁₂ PFAAs range from 3.3 to 4.3. Affinity for BSA increases with PFAA hydrophobicity but decreases from the C₈ to C₁₂ PFCAs, likely due to steric hindrances associated with longer and more rigid perfluoroalkyl chains. The C₄-sulfonate exhibits increased affinity relative to the equivalent chain-length PFCA. Fluorescence titrations support evidence that an observed dependence of PFAA-BSA binding on pH is attributable to conformational changes in the protein. Association constants determined for perfluorobutanesulfonate and perfluoropentanoate with BSA are on the order of those for long-chain PFAAs (K(a) ∼10⁶/M), suggesting that physiological implications of strong binding to albumin may be important for short-chain PFAAs.

Abstract  PURPOSE: Samples from the German Environmental Specimen Bank (ESB) covering particularly the years 1994-1996, 2000-2002, and 2006-2009 were analyzed for perfluorinated compounds (PFC; mainly C4-C13 carboxylic and sulfonic acids) to gain an overview on current PFC levels and patterns in marine, limnetic, and terrestrial biota; to assess their concentrations in different trophic levels; and to investigate whether risk management measures for PFC are successful.

METHODS: Specimens, either standardized annual pooled samples (blue mussels, eelpout liver, bream liver, pigeon eggs) or individual single samples (cormorant eggs, rook eggs), were collected for the German ESB program from representative sampling sites according to documented guidelines. After appropriate extraction, PFC were quantified under ISO/IEC 17025 accreditation by HPLC/MS-MS with isotopically labeled internal standards. Limits of quantification (LOQs) were 0.2-0.5 ng/g. Data are reported on a wet weight basis.

RESULTS AND DISCUSSION: In most samples the predominant PFC was perfluorooctane sulfonic acid (PFOS). However, in marine mussels from North and Baltic Seas, PFOS levels were mostly below the LOQ, but low residues of PFOS amide were found which declined in recent years. Livers of eelpout showed maximum concentrations of 15-25 ng/g PFOS in the period 2000-2002 and low amounts of perfluoropentanoate in all years. Beside PFOS (median 48 ng/g) several PFC could be determined in cormorant eggs sampled in 2009 from a Baltic Sea site. For a freshwater ecosystem, current PFC burdens for cormorant eggs were even higher (median 400 ng/g PFOS). Livers of bream from rivers showed concentrations of 130-260 ng/g PFOS, but for bream from a reference lake levels were only about 6 ng/g. In contrast to cormorants, eggs of rook and feral pigeon from terrestrial ecosystems displayed only low PFC burdens (up to 6 ng/g PFOS).

CONCLUSIONS: Generally, PFC levels were lower in marine than in freshwater biota. PFC burdens were higher in biota from the ESB-North Sea sites than in Baltic Sea organisms. Levels of PFC were quite high especially in top predators of both limnetic and marine ecosystems. Only low PFC levels were detected in eggs of terrestrial birds. A decrease of PFOS levels from maximum values around the year 2000 observed at least in North Sea biota may be a result of a production cease and shifts in marketing pattern.

Abstract  The mass spectra of the controlled substance 3,4-MDMA and its regioisomer 2,3-MDMA are characterized by an imine fragment base peak at m/z 58 and additional fragments at m/z 135/136 for the methylenedioxybenzyl cation and radical cation, respectively. Three positional ring methoxy isomers of N-methyl-2-(methoxyphenyl)-3-butanamine (MPBA) have an isobaric relationship to 2,3- and 3,4-MDMA. All five compounds have the same molecular weight and produce similar EI mass spectra. This lack of mass spectral specificity for the isomers in addition to the possibility of chromatographic co-elution could result in misidentification. The lack of reference materials for the potential imposter molecules constitutes a significant analytical challenge. Perfluoroacylation of the amine group reduced the nitrogen basicity and provided individual fragmentation pathways for discrimination among these compounds based on unique fragment ions and the relative abundance of common ions. Studies using gas chromatography with infrared detection provided additional structure-IR spectra relationships. The underivatized amines and the perfluoroacylated derivatives (PFPA and HFBA) were resolved by capillary gas chromatography on a 100% dimethylpolysiloxane stationary phase. The perfluoroacylated derivatives showed better resolution on a cyclodextrin modified stationary phase.

Abstract  Mass spectral differentiation of 3,4-methylenedioxymethamphetamine (3,4-MDMA), a controlled drug, and its 2,3-regioisomer from the ring substituted ethoxyphenethylamines is possible after formation of the perfluoroacyl derivatives, pentafluoropropionamides (PFPA), and heptafluorobutyrylamides (HFBA). The ring substituted ethoxyphenethylamines constitute a unique set of compounds having an isobaric relationship with 3,4-MDMA. These isomeric forms of the 2-, 3-, and 4-ethoxy phenethylamines have mass spectra essentially equivalent to 3,4-MDMA; all have molecular weight of 193 and major fragment ions in their electron ionization mass spectra at m/z 58 and 135/136. All the side chain regioisomers of 2-ethoxy phenethylamine having equivalent mass spectra to 3,4-MDMA are synthesized and compared via gas chromatography-mass spectrometry to 2,3- and 3,4-methylenedioxymethamphetamine. The mass spectra for the perfluoroacyl derivatives of the primary and secondary amine regioisomers are significantly individualized, and the side chain regioisomers yield unique hydrocarbon fragment ions at m/z 148, 162, and 176. Additionally, the substituted ethoxymethamphetamines are distinguished from the methylenedioxymethamphet-amines via the presence of the m/z 107 ion. Gas chromatographic separation on relatively non-polar stationary phases successfully resolves these derivatives.

Abstract  Five side chain regioisomers of 2-methoxy-4-methylphenethylamine constitute a unique set of compounds having an isobaric relationship with the controlled drug substance 3,4-methylenedioxymethamphetamine (3,4-MDMA or Ecstasy). These isomeric forms of the 2-methoxy-4-methyl-phenethylamines have mass spectra essentially equivalent to 3,4-MDMA; all have molecular weight of 193 and major fragment ions in their electron ionization mass spectra at m/z 58 and 135/136. Mass spectral differentiation of 2,3 and 3,4-MDMA from primary and secondary amine regioisomeric side chains of 2-methoxy-4-methyl-phenethylamines was possible after formation of the perfluoroacyl derivatives, pentafluoropropionamides (PFPA) and heptafluorobutyrylamides (HFBA). The mass spectra for these derivatives are individualized and the resulting unique fragment ions allow for specific side-chain identification. The individualization is the result of fragmentation of the alkyl carbon-nitrogen bond yielding unique hydrocarbon fragments of varying mass. Gas chromatographic separation on relatively non-polar stationary phases gave essentially base line resolution for these compounds.

Abstract  Decomposition of perfluorinated chemicals is of significant interest in both scientific and industrial perspectives. Here, we report the decomposition of perfluorooctanoic acid (PFOA) under sonication-assisted photocatalysis by utilizing commercial TiO(2) (RdH) and home-made TiO(2) (sol-gel) as photocatalysts at ambient temperature, pressure and near neutral pH with the irradiation of 254nm UV light. PFOA was decomposed into fluoride ions and to several perfluorinated carboxylic acids (PFCAs) with a shorter carbon chain length such as perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropropanoic acid (PFPA), and trifluoroacetic acid (TFA). The efficiency of sonication-assisted photocatalysis was found to be 64%. In all the cases, higher efficiencies were obtained when sol-gel TiO(2) was used as a photocatalyst than the commercial RdH TiO(2) catalyst. The specific surface area is three times higher for sol-gel TiO(2) than commercial RdH TiO(2) and appears to be the probable reason for the observed differences in the corresponding efficiencies. It is also interesting to note that pH plays a determining role in the decomposition of PFOA and correspondingly photocatalyses were carried out under different controlled pH. Perfluoroalkyl radicals are presumably oxidized by superoxide and hydroxyl radicals generated during the TiO(2)-mediated photocatalysis at pH 4 and 10, respectively. The role of sonication in sonication-assisted photocatalysis was construed to be an aid to photocatalysis than a tool itself. Sonication enhances photocatalysis through physical dispersion of TiO(2) and eases mass transfer which keeps on rejuvenating the TiO(2) surface.

Abstract  The spatial trend of perfluoroalkyl substances (PFASs) along Xiaoqing River and its tributaries was studied to characterize isomer profiles and quantify emissions from fluoropolymer (FP) manufacturers in China. Substantially elevated ∑PFAS concentrations downstream of tributary 4 demonstrated that the emissions from this FP manufacturer dominated total riverine discharges. Isomer profiles of perfluorooctanoic acid (PFOA) in water displayed a stepwise increase in percentage branched PFOA downstream of tributary 3 (14.0%) and 4 (22.7%) reflecting the importance of FP sources. Strong positive correlations between PFOA isomers in water downstream of tributary 4 indicated that isomer profiles were conserved from emission sources to the final reservoir. Riverine discharges of PFOA (23-67 t/yr) were in agreement with theoretical emission calculations from FP production (68 t/yr) whereas large discrepancies between the two methodologies were observed for perfluorobutanoic acid and perfluoropentanoic acid. Collectively, this study fills critical knowledge gaps for understanding ongoing global sources of PFASs.

Abstract  Bench- and pilot-scale sorption tests were used to probe the performance of several biochars at removing perfluoroalkyl acids (PFAA) from field waters, compared to granular activated carbon (GAC). Screening tests using organic matter-free water resulted in hardwood (HWC) (Kd = 41 L g(-1)) and pinewood (PWC) (Kd = 49 L g(-1)) biochars having the highest perfluorooctanoic acid (PFOA) removal performance that was comparable to bituminous coal GAC (Kd = 41 L g(-1)). PWC and HWC had a stronger affinity for PFOA sorbed in Lake Mead surface water (KF = 11 mg((1-n)) L(n) g(-1)) containing a lower (2 mg L(-1)) dissolved organic carbon (DOC) concentration than in a tertiary-filtered wastewater (KF = 8 mg((1-n)) L(n) g(-1)) with DOC of 4.9 mg L(-1). A pilot-scale study was performed using three parallel adsorbers (GAC, anthracite, and HWC biochar) treating the same tertiary-filtered wastewater. Compared to HWC, and anthracite, GAC was the most effective in mitigating perfluoropentanoic acid (PFPnA), perfluorohexanoic acid (PHxA), PFOA, perfluorooctane sulfonic acid (PFOS), and DOC (45-67% removed at 4354 bed volumes) followed by HWC, and then anthracite. Based on bench- and pilot-scale results, shorter-chain PFAA [perfluorobutanoic acid (PFBA), PFPnA, or PFHxA] were more difficult to remove with both biochar and GAC than the longer-chain, PFOS and PFOA.

Abstract  In late 2014, wastewater effluent samples were collected from eight treatment plants that discharge to San Francisco (SF) Bay in order to assess poly- and perfluoroalkyl substances (PFASs) currently released from municipal and industrial sources. In addition to direct measurement of twenty specific PFAS analytes, the total concentration of perfluoroalkyl acid (PFAA) precursors was also indirectly measured by adapting a previously developed oxidation assay. Effluent from six municipal treatment plants contained similar amounts of total PFASs, with highest median concentrations of PFHxA (24 ng/L), followed by PFOA (23 ng/L), PFBA (19 ng/L), and PFOS (15 ng/L). Compared to SF Bay municipal wastewater samples collected in 2009, the short chain perfluorinated carboxylates PFBA and PFHxA rose significantly in concentration. Effluent samples from two treatment plants contained much higher levels of PFASs: over two samplings, wastewater from one municipal plant contained an average of 420 ng/L PFOS and wastewater from an airport industrial treatment plant contained 560 ng/L PFOS, 390 ng/L 6:2 FtS, 570 ng/L PFPeA, and 500 ng/L PFHxA. The elevated levels observed in effluent samples from these two plants are likely related to aqueous film forming foam (AFFF) sources impacting their influent; PFASs attributable to both current use and discontinued AFFF formulations were observed. Indirectly measured PFAA precursor compounds accounted for 33%-63% of the total molar concentration of PFASs across all effluent samples and the PFAA precursors indicated by the oxidation assay were predominately short-chained. PFAS levels in SF Bay effluent samples reflect the manufacturing shifts towards shorter chained PFASs while also demonstrating significant impacts from localized usage of AFFF.

Abstract  Aqueous photo-reductive decomposition of perflurooctanoic acid (PFOA) was investigated as a function of temperature (293, 298, and 313K) and ionic strength (2.5, 5.0, or 20.0mmol/L as NaCl). As an advanced reduction process, iodide was used under UV irradiation to produce highly reactive reducing reagent hydrated electrons. PFOA was reduced by hydrated electrons and short-chain perfluorinated acid intermediates including perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, perfluorobutyric acid, pentafluoropropionic acid, and trifluoroacetic acid were detected during the reaction. In this study, the same intermediates were observed under different temperature and ionic strength conditions. It was found that the increase of reaction temperature could positively affect the decomposition of PFOA. Defluorination of PFOA was observed to increase as the temperature increased. After 6h, the defluorination efficiency increased from 47.71% to 80.91% when the system temperature increased from 293 to 313K. As the temperature increased, the maximum concentration of the six short-chain perfluorinated acid intermediates decreased. Meanwhile, there was a positive correlation between the ionic strength and PFOA decomposition rate. According to the BrOnsted-Bjerrum equation, Z(A)Z(B) was calculated to be 2.2, indicating that both single-charged and double-charged species play a role during the decomposition process.

Abstract  The aerobic biodegradation of [1,2-(14)C] 6:2 FTOH [F(CF(2))(6)(14)CH(2)(14)CH(2)OH] in a flow-through soil incubation system is described. Soil samples dosed with [1,2-(14)C] 6:2 FTOH were analyzed by liquid scintillation counting, LC/ARC (liquid chromatography/accurate radioisotope counting), LC/MS/MS, and thermal combustion to account for 6:2 FTOH and its transformation products over 84 d. Half of the [1,2-(14)C] 6:2 FTOH disappeared from soil in 1.3 d, undergoing simultaneous microbial degradation and partitioning of volatile transformation product(s) and the 6:2 FTOH precursor into the air phase. The overall (14)C (radioactivity) mass balance in live and sterile treatments was 77-87% over 84-d incubation. In the live test system, 36% of total (14)C dosed was captured in the airflow (headspace), 25% as soil-bound residues recovered via thermal combustion, and 16% as soil extractable. After 84 d, [(14)C] 5:2 sFTOH [F(CF(2))(5)CH(OH)(14)CH(3)] was the dominant transformation product with 16% molar yield and primarily detected in the airflow. The airflow also contained [1,2-(14)C] 6:2 FTOH and (14)CO(2) at 14% and 6% of total (14)C dosed, respectively. The other significant stable transformation products, all detected in soil, were 5:3 acid [F(CF(2))(5)CH(2)CH(2)COOH, 12%], PFHxA [F(CF(2))(5)COOH, 4.5%] and PFPeA [F(CF(2))(4)COOH, 4.2%]. Soil-bound residues as well as conjugates between fluorinated transformation products and dissolved soil components were only observed in the live test system and absent in the sterile soil, suggesting that such binding and complexation are microbially or enzymatically driven processes. At day 84, 5:3 acid is postulated to be the major transformation product in soil-bound residues, which may not be available for further biodegradation in soil environment.

Abstract  The concentrations of eighteen perfluorinated compounds (PFCs: C5-C14 carboxylates, C4, C6-C8 and C10 sulfonates and 3 sulfonamides) were determined in wastewater and sludge samples originating from two different wastewater treatment plants (WWTPs). The analytes were extracted by solid phase extraction (dissolved phase) or sonication followed by solid phase extraction (solid phase). Qualitative and quantitative analyses were performed by LC-MS/MS. According to the results, perfluoropentanoic acid (PFPeA), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were dominant in wastewater and sludge samples from both plants. The average concentrations in the raw and treated wastewater ranged up to 75.7 ng L(-1) (perfluorotridecanoic acid, PFTrDA) and 76.0 ng L(-1) (PFPeA), respectively. Concentrations of most PFCs were higher in effluents than in influents, indicating their formation during wastewater treatment processes. In sewage sludge, the average concentrations ranged up to 6.7 ng g(-1) dry weight (PFOS). No significant seasonal variations in PFCs concentrations were observed, while higher concentrations of PFOA, PFOS and perfluorononanoic acid (PFNA) were determined in the WWTP receiving municipal and industrial wastewater. Significantly different distribution coefficient (Kd) values were determined for different PFCs and different type of sludge, ranging between 169 L kg(-1) (PFHxS) to 12,922 L kg(-1) (PFDA).

Abstract  This study investigated the occurrence of perfluoroalkyl acids (PFAAs) in surface water from 67 sampling sites along rivers of the Pearl River Delta in southern China. Sixteen PFAAs, including perfluoroalkyl carboxylic acids (PFCAs, C5-14, C16 and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8 and C10) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFAA concentrations (∑ PFAAs) in the surface water ranged from 1.53 to 33.5ng·L(-1) with an average of 7.58ng·L(-1). Perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS) were the three most abundant PFAAs and on average accounted for 28%, 16% and 10% of ∑ PFAAs, respectively. Higher concentrations of ∑ PFAAs were found in the samples collected from Jiangmen section of Xijiang River, Dongguan section of Dongjiang River and the Pearl River flowing the cities which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of extracted sources. Factor 1 (72.48% of the total variance) had high loading for perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), PFBS and PFOS. For factor 2 (10.93% of the total variance), perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUdA) got high loading. The sorption of PFCAs on suspended particulate matter (SPM) increased by approximately 0.1logunits for each additional CF2 moiety and that on sediment was approximately 0.8logunits lower than the SPM logKd values. In addition, the differences in the partition coefficients were influenced by the structure discrepancy of absorbents and influx of fresh river water. These data are essential for modeling the transport and environmental fate of PFAAs.

Abstract  In order to explore the residue characteristics and distributions of 15 perfluorinated compounds (PFCs) in 18 surface seawater samples along Shenzhen coastline, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with solid phase extraction enrichment was applied in this research. The results indicated that residue level of PFCs in coastal surface seawater samples was significantly affected by human activities. Sigma PFCs residue levels in surface seawater from Shenzhen west coast, which locates below the estuary of Pearl River and Dongbao River, are much higher than those from the east coast, which has low development and sparse population (P < 0.05). Under natural conditions, Sigma PFCs residue levels in coastal surface seawater samples from Shenzhen Bays are higher than those out of bays. The major residue species in surface seawater samples along Shenzhen coast were medium- and short-chain PFCs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanoic acid and perfluoropentanoic acid. Their similar environmental behavior (P < 0.05, P < 0.01) is likely associated with the production process of PFCs-related products. Furthermore, cluster analysis results show that PFOS (R-2 = 0. 409 2) level can be used as a representative parameter for evaluating PFCs contamination status in surface seawater along Shenzhen coast.

Abstract  Organic anion transporting polypeptide (Oatp) 1a1 has been hypothesized to play a key role in rat renal reabsorption of perfluorooctanoate (PFO). We have investigated PFO uptake kinetics in Chinese Hamster Ovary (CHO) cells that have been stably transfected with the cDNA encoding Oatp1a1. The Oatp1a1-expressing CHO cells have been validated by their Oatp1a1 gene expression, estrone-3-sulfate (E3S) uptake kinetics, and the correlation between Oatp1a1 gene expression and E3S uptake activity that were both induced by the treatment of sodium butyrate. Oatp1a1-mediated PFO uptake underwent a saturable process with a K(m) value of 162.2+/-20.2microM, which was effectively inhibited by known Oatp1a1 substrates sulfobromophthalein and taurocholate, and a major flavonoid in grapefruit juice, naringin. The inhibition of Oatp1a1-mediated E3S uptake has been compared for linear perfluorocarboxylates with carbon chain lengths ranged from 4 to 12. There was no apparent inhibition by perfluorobutanoate and perfluoropentanoate at 1mM. Inhibition was observed for perfluorohexanoate at 1mM and the level of inhibition increased as the increase of the chain length up to perfluorodecanoate. The values of apparent inhibition constant (K(i,app)) were determined for perfluorocarboxylates with chain lengths between 6 and 10. The log values of K(i,app) exhibited a negative linear relationship to the chain lengths and a positive linear relationship to the log values of the total clearance of perfluorocarboxylates in male rats. This in vitro-to-in vivo correlation strongly supports a tubular reabsorptive role of Oatp1a1 in rat renal elimination of perfluorocarboxylates. Due to the sex-dependent expression of Oatp1a1 in rat kidney, Oatp1a1-mediated tubular reabsorption is suggested to be the mechanism for the sex-dependent renal elimination of PFO in rats.

Abstract  Jiangsu Hi-tech Fluorochemical Industry Park, China, is one of the largest fluorochemical industry centers in Asia and could be a point source of polyfluoroalkyl substances (PFASs) to the surrounding environment. Besides water, sediment and soil samples, tree leaves and bark were also collected to monitor airborne PFASs around the facilities. Perfluorooctanoic acid and short-chain perfluorocarboxylates including perfluorohexanoic acid and perfluoropentanoic acid were found predominantly in all the samples. The target ∑PFASs were distributed in the dissolved phase with a proportion of 96.5±2.9%. High concentrations of ∑PFASs (up to 12,700 ng/L in surface water) were found at sites near and within the wastewater treatment plant and the facilities. The ∑PFASs in the sediment/sludge were in the range of 3.33-324 ng/g dw. For the first time, tree samples were used for bio-monitoring airborne PFASs in the environment. The ∑PFASs in the tree leaf and bark samples were in the range of 10.0-276 and 6.76-120 ng/g dw, respectively. The spatial distribution of ∑PFASs in the tree leaves suggested that airborne PFASs could be transported from the center to the surrounding environment by prevailing wind.

Abstract  Morantel, pyrantel and their drug-related metabolites in food of animal-origin are regulated as sum of residues which may be hydrolysed to N-methyl-1,3-propanediamine (NMPA). In this study, an isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS) method with pentafluoropropionic acid anhydride (PFPA) derivatization was developed for the determination of NMPA in bovine muscle. A stable isotope labeled internal standard N-methyl-d(3)-3,3'-d(2)-propane-1,3-diamine (NMPA-d(5)) was synthesized as internal standard. NMPA was derivatized with PFPA to form an N,N'-bis (pentafluoroacyl) derivative (NMPA-PFPA) and analyzed by liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS/MS) and liquid chromatography ion trap mass spectrometry (LC-IT-MS/MS) using negative ion electrospray ionization (ESI). Chromatographic behavior of several perfluorocarboxylic acid anhydride derivatives of NMPA and other structurally related diamines on C-18 and perfluorophenyl (PFP) columns was studied. Conversion of the parent drugs to NMPA under various hydrolysis conditions was evaluated. In addition, comparison of the matrix effect and linearity with isotopically labeled internal standard (I.S.) and analogous I.S. were performed and investigated. The method was validated using fortified bovine muscle samples. The apparent recovery (obtained after correction with an isotopically labeled I.S.) was between 89% and 97% and repeatability was less than 10%. The lowest LOD and LOQ (0.42 and 1.39μg/kg, respectively) were obtained with LC-QqQ-MS/MS.

Abstract  The effects of acute toxicity, 3-day population growth and morphological effects of perfluorinated carboxylic acids (PFCAs) with carbon chain lengths of 2-6 on the freshwater rotifer Brachionus calyciflorus were investigated. The results indicated that the 24-h median lethal concentration (LC50) values of trifluoroacetic acid (TFA), perfluoropropionic acid (PFPrA), perfluorobutanoic acid (PFBA), perfluopentanoic acid (PFPeA), and perfluorohexanoic acid (PFHxA) towards B. calyciflorus were 70, 80, 110, 130 and 140mgL(-1), respectively. The acute effects of PFCAs decreased with the increase of carbon chain length. The parameters used to determine 3-day population growth on these compounds were the rate of population increase (r) and mictic ratio. With the increase of fluorinated carbon-chain length, the r values of TFA, PFPrA, PFBA, PFPeA and PFHxA decreased by 0.99%, 16.8%, 16.5%, 22.4% and 32.0%, respectively. Mictic ratios ranged from 0.707 to 0.953 for PFCAs with carbon chain lengths of 2-6. In addition, the mictic ratio, body size and egg size exposed to some PFCAs were higher than those of the controls. These results offer a useful method for the ecological risk assessment of these short chain PFCAs.

Abstract  The presence of perfluoroalkyl acids (PFAAs) in biosolids destined for use in agriculture has raised concerns about their potential to enter the terrestrial food chain via bioaccumulation in edible plants. Uptake of PFAAs by greenhouse lettuce ( Lactuca sativa ) and tomato ( Lycopersicon lycopersicum ) grown in an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and a control soil was measured. Bioaccumulation factors (BAFs) were calculated for the edible portions of both lettuce and tomato. Dry weight concentrations observed in lettuce grown in a soil amended (biosolids:soil dry weight ratio of 1:10) with PFAA industrially contaminated biosolids were up to 266 and 236 ng/g for perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPeA), respectively, and reached 56 and 211 ng/g for PFBA and PFPeA in tomato, respectively. BAFs for many PFAAs were well above unity, with PFBA having the highest BAF in lettuce (56.8) and PFPeA the highest in tomato (17.1). In addition, the BAFs for PFAAs in greenhouse lettuce decreased approximately 0.3 log units per CF2 group. A limited-scale field study was conducted to verify greenhouse findings. The greatest accumulation was seen for PFBA and PFPeA in both field-grown lettuce and tomato; BAFs for PFBA were highest in both crops. PFAA levels measured in lettuce and tomato grown in field soil amended with only a single application of biosolids (at an agronomic rate for nitrogen) were predominantly below the limit of quantitation (LOQ). In addition, corn ( Zea mays ) stover, corn grains, and soil were collected from several full-scale biosolids-amended farm fields. At these fields, all PFAAs were below the LOQ in the corn grains and only trace amounts of PFBA and PFPeA were detected in the corn stover. This study confirms that the bioaccumulation of PFAAs from biosolids-amended soils depends strongly on PFAA concentrations, soil properties, the type of crop, and analyte.

Abstract  Perfluoroalkyl compounds (PFCs) were determined in 22 surface water samples (39-76°N) and three sea ice core and snow samples (77-87°N) collected from North Pacific to the Arctic Ocean during the fourth Chinese Arctic Expedition in 2010. Geographically, the average concentration of ∑PFC in surface water samples were 560 ± 170 pg L(-1) for the Northwest Pacific Ocean, 500 ± 170 pg L(-1) for the Arctic Ocean, and 340 ± 130 pg L(-1) for the Bering Sea, respectively. The perfluoroalkyl carboxylates (PFCAs) were the dominant PFC class in the water samples, however, the spatial pattern of PFCs varied. The C(5), C(7) and C(8) PFCAs (i.e., perfluoropentanoate (PFPA), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA)) were the dominant PFCs in the Northwest Pacific Ocean while in the Bering Sea the PFPA dominated. The changing in the pattern and concentrations in Pacific Ocean indicate that the PFCs in surface water were influenced by sources from the East-Asian (such as Japan and China) and North American coast, and dilution effect during their transport to the Arctic. The presence of PFCs in the snow and ice core samples indicates an atmospheric deposition of PFCs in the Arctic. The elevated PFC concentration in the Arctic Ocean shows that the ice melting had an impact on the PFC levels and distribution. In addition, the C(4) and C(5) PFCAs (i.e., perfluorobutanoate (PFBA), PFPA) became the dominant PFCs in the Arctic Ocean indicating that PFBA is a marker for sea ice melting as the source of exposure.

Abstract  The 6:2 FTOH [F(CF(2))(6)CH(2)CH(2)OH] is a major raw material being used to replace 8:2 FTOH [F(CF(2))(8)CH(2)CH(2)OH] to make FTOH-based products for industrial and consumer applications. A novel aerobic sediment experimental system containing 20 g wet sediment and 30 mL aqueous solution was developed to study 6:2 FTOH biotransformation in river sediment. 6:2 FTOH was dosed into the sediment to follow its biotransformation and to analyze transformation products over 100 d. The primary 6:2 FTOH biotransformation in the aerobic sediment system was rapid (T(1/2)<2d). 5:3 acid [F(CF(2))(5)CH(2)CH(2)COOH] was observed as the predominant polyfluorinated acid on day 100 (22.4 mol%), higher than the sum of perfluoropentanoic acid (10.4 mol%), perfluorohexanoic acid (8.4 mol%), and perfluorobutanoic acid (1.5 mol%). Perfluoroheptanoic acid was not observed during 6:2 FTOH biotransformation. The 5:3 acid can be further degraded to 4:3 acid [F(CF(2))(4)CH(2)CH(2)COOH, 2.7 mol%]. This suggests that microbes in the river sediment selectively degraded 6:2 FTOH more toward 5:3 and 4:3 acids compared with soil. Most of the observed 5:3 acid formed bound residues with sediment organic components and can only be quantitatively recovered by post-treatment with NaOH and ENVI-Carb™ carbon. The 6:2 FTCA [F(CF(2))(6)CH(2)COOH], 6:2 FTUCA [F(CF(2))(5)CF=CHCOOH], 5:2 ketone [F(CF(2))(5)C(O)CH(3)], and 5:2 sFTOH [F(CF(2))(5)CH(OH)CH(3)] were major transient intermediates during 6:2 FTOH biotransformation in the sediment system. These results suggest that if 6:2 FTOH or 6:2 FTOH-based materials were released to the river or marine sediment, poly- and per-fluorinated carboxylates could be produced.

Abstract  The polyfluorinated carboxylic acids 5:3 acid (C(5)F(11)CH(2)CH(2)CO(2)H) and 7:3 acid (C(7)F(15)CH(2)CH(2)CO(2)H) are major products from 6:2 FTOH (C(6)F(13)CH(2)CH(2)OH) and 8:2 FTOH (C(8)F(17)CH(2)CH(2)OH) aerobic biotransformation, respectively. The 5:3 and 7:3 acids were dosed into domestic WWTP activated sludge for 90 d to determine their biodegradability. The 7:3 acid aerobic biodegradability was low, only 1.7 mol% conversion to perfluoroheptanoic acid (PFHpA), whereas no transformation was observed previously in soil. In stark contrast, 5:3 acid aerobic biodegradability was enhanced 10 times in activated sludge compared to soil. The 5:3 acid was not activated by acyl CoEnzyme A (CoA) synthetase, a key step required for further α- or ß-oxidation. Instead, 5:3 acid was directly converted to 4:3 acid (C(4)F(9)CH(2)CH(2)CO(2)H, 14.2 mol%) and 3:3 acid (C(3)F(7)CH(2)CH(2)CO(2)H, 0.9 mol%) via "one-carbon removal pathways". The 5:3 acid biotransformation also yielded perfluoropentanoic acid (PFPeA, 5.9 mol%) and perfluorobutanoic acid (PFBA, 0.8 mol%). This is the first report to identify key biotransformation intermediates which demonstrate novel one-carbon removal pathways with sequential removal of CF(2) groups. Identified biotransformation intermediates (10.2 mol% in sum) were 5:3 Uacid, α-OH 5:3 acid, 5:2 acid, and 5:2 Uacid. The 5:2 Uacid and 5:2 acid are novel intermediates identified for the first time which confirm the proposed pathways. In the biodegradation pathways, the genesis of the one carbon removal is CO(2) elimination from α-OH 5:3 acid. These results suggest that there are enzymatic mechanisms available in the environment that can lead to 6:2 FTOH and 5:3 acid mineralization. The dehydrogenation from 5:3 acid to 5:3 Uacid was the rate-limiting enzymatic step for 5:3 acid conversion to 4:3 acid.