Bogdan Szostek

8-2 Fluorotelomer alcohol aerobic soil biodegradation: Pathways, metabolites, and metabolite yields

The biodegradation pathways and metabolite yields of [3-(14)C] 8-2 fluorotelomer alcohol [8-2 FTOH, F(CF(2))(7)(14)CF(2)CH(2)CH(2)OH) in aerobic soils were investigated. Studies were conducted under closed (static) and continuous headspace air flow to assess differences in degradation rate and metabolite concentrations in soil and headspace. Aerobic degradation pathways in soils were in general similar to those in aerobic sludge and bacterial culture. (14)C mass balance was achieved in soils incubated for up to 7 months. Up to 35% (14)C dosed was irreversibly bound to soils and was only recoverable by soil combustion. The average PFOA yield was approximately 25%. Perfluorohexanoic acid (PFHxA) yield reached approximately 4%. (14)CO(2) yield was 6.8% under continuous air flow for 33 days. Three metabolites not previously identified in environmental samples were detected: 3-OH-7-3 acid [F(CF(2))(7)CHOHCH(2)COOH], 7-2 FT ketone [F(CF(2))(7)COCH(3)] and 2H-PFOA [F(CF(2))(6)CFHCOOH]. No perfluorononanoic acid (PFNA) was observed. The formation of 2H-PFOA, PFHxA, and (14)CO(2) shows that multiple -CF(2)- groups were removed from 8-2 FTOH. 7-3 Acid [F(CF(2))(7)CH(2)CH(2)COOH] reached a yield of 11% at day 7 and did not change thereafter. 7-3 Acid was incubated in aerobic soil and did not degrade to PFOA. 7-2 sFTOH [F(CF(2))(7)CH(OH)CH(3)], a transient metabolite, was incubated and degraded principally to PFOA. 7-3 Acid may be a unique metabolite from 8-2 FTOH biodegradation. The terminal ratio of PFOA to 7-3 acid ranged between 1.8-2.5 in soils and 0.6-3.2 in activated sludge, sediment, and mixed bacterial culture. This ratio may be useful in evaluating environmental samples to distinguish the potential contribution of 8-2 FTOH biodegradation to PFOA observed versus PFOA originating from other sources.

Investigation of natural dyes occurring in historical Coptic textiles by high-performance liquid chromatography with UV-Vis and mass spectrometric detection

Liquid chromatography (LC) combined with ultraviolet-visible (UV-Vis) and mass spectrometric (MS) detection was utilized to study the chemical components present in extracts of natural dyes originating from fiber samples obtained from Coptic textiles from Early Christian Art Collection of National Museum in Warsaw. Chromatographic retention, ionization, UV-Vis and mass spectra of twenty selected dye compounds of flavanoid-, anthraquinone- and indigo-types were studied. Most of the investigated compounds could be ionized by positive and negative ion electrospray ionization. Difficulties with the ionization by electrospray were experienced for indigotin and brominated indigotins, but these were ionized by atmospheric pressure chemical ionization. Mass spectrometric detection, utilizing different scanning modes of a triple quadrupole mass spectrometer, combined with the UV-Vis detection was demonstrated to be a powerful approach to detection and identification of dyes in the extracts of archeological textiles. Using this approach the following compounds were identified in the extracts of Coptic textiles: luteolin, apigenin, rhamnetin, kaempferol, alizarin, purpurin, xanthopurpurin, monochloroalizarin, indirubin, and so the type of dye that was utilized to dye the textiles could be identified. Detection capabilities for several dye-type analytes were compared for the UV-Vis and mass spectrometric detection. The signal-to-noise ratios obtained for luteolin, apigenin, and rhamnetin were higher for the MS detection for most of the examined sample extracts. Purpurin, alizarin, and indirubin showed similar signal-to-noise ratios for UV-Vis and mass spectrometric detection.

6-2 Fluorotelomer alcohol aerobic biodegradation in soil and mixed bacterial culture

The first studies to explore 6-2 fluorotelomer alcohol [6-2 FTOH, F(CF(2))(6)CH(2)CH(2)OH] aerobic biodegradation are described. Biodegradation yields and metabolite concentrations were determined in mixed bacterial culture (90d) and aerobic soil (180d). 6-2 FTOH primary degradation half-life was less than 2d in both. The overall mass balance in mixed bacterial culture (day 90) was approximately 60%. At day 90, the molar yield was 6% for 6-2 FTA [F(CF(2))(6)CH(2)COOH], 23% for 6-2 FTUA [F(CF(2))(5)CFCHCOOH], 16% for 5-2 sFTOH [F(CF(2))(5)CHOHCH(3)], 6% for 5-3 acid [F(CF(2))(5)CH(2)CH(2)COOH], and 5% for PFHxA [F(CF(2))(5)COOH]. The overall mass balance in aerobic soil was approximately 67% (day 180). At day 180, the major terminal metabolites were PFPeA, [F(CF(2))(4)COOH, 30%], PFHxA (8%), PFBA [F(CF(2))(3)COOH, 2%], and 5-3 acid (15%). A new metabolite 4-3 acid [F(CF(2))(4)CH(2)CH(2)COOH] accounted for 1%, 6-2 FTOH for 3%, and 5-2 sFTOH for 7%. Based on 8-2 FTOH aerobic biodegradation pathways, PFHxA was expected in greatest yield from 6-2 FTOH degradation. However, PFPeA was observed in greatest yield in soil, suggesting a preference for alternate degradation pathways. Selected metabolites were also studied in aerobic soil. 5-3 Acid degraded to only 4-3 acid with a molar yield of 2.3%. 5-2 sFTOH degraded to PFPeA and PFHxA, and 5-2 FT Ketone [F(CF(2))(5)COCH(3)] degraded to 5-2 sFTOH, suggesting that 5-2 sFTOH is the direct precursor to PFPeA and PFHxA. Another new metabolite, 5-3 ketone aldehyde [F(CF(2))(5)COCH(2)CHO] was also identified in mixed bacterial culture. The formation of PFBA, PFPeA, and 4-3 acid indicates that multiple -CF(2)- groups in 6-2 FTOH were removed during microbial biodegradation.

Investigating the biodegradability of perfluorooctanoic acid

Perfluorooctanoic acid (PFOA) is an industrial chemical that has become disseminated globally in aquatic and terrestrial habitats, humans, and wildlife. Understanding PFOAs biodegradability (susceptibility to microbial metabolic attack) is a crucial element in developing an informed strategy for predicting and managing this compounds environmental fate. Reasoning that PFOA might be susceptible to reductive defluorination by anaerobic microbial communities, we embarked on a 2-phase experimental approach examining the potential of five different microbial communities (from a municipal waste-water treatment plant, industrial site sediment, an agricultural soil, and soils from two fire training areas) to alter PFOAs molecular structure. A series of primarily anaerobic incubations (up to 259d in duration) were established with acetate, lactate, ethanol, and/or hydrogen gas as electron donors and PFOA (at concentrations of 100 ppm and 100 ppb) as the electron acceptor. Cometabolism of PFOA during reductive dechlorination of trichloroethene (TCE) and during reduction of nitrate, iron, sulfate, and methanogenesis were also examined. Endpoints of potential PFOA transformation included release of fluoride and detection of potential transformation products by LC/Orbitrap MS and LC/accurate radioisotope counting in a (14)C radiotracer study. The strongest indication of PFOA transformation occurred during its potential cometabolism at the 100 ppb concentration during reductive dechlorination of TCE. Despite an extensive search for transformation products to corroborate potential cometabolism of PFOA, we were unable to document any alteration of PFOAs chemical structure. We conclude that, under conditions examined, PFOA is microbiologically inert, hence environmentally persistent.

6:2 and 8:2 fluorotelomer alcohol anaerobic biotransformation in digester sludge from a WWTP under methanogenic conditions.

6:2 FTOH and 8:2 FTOH [FTOHs, F(CF2)nCH2CH2OH, n = 6, 8] are the principal polyfluorinated raw materials used to manufacture FTOH-based products, which may be released to WWTPs during their product life cycle. For the first time, anaerobic biotransformation of FTOHs and key biotransformation intermediates in WWTP digester sludge under methanogenic conditions was investigated. 6:2 FTOH was transformed to 6:2 FTCA, [F(CF2)6CH2COOH, 32-43 mol %], 6:2 FTUCA [F(CF2)5CF═CHCOOH, 1.8-8.0 mol %], and 5:3 acid [F(CF2)5CH2CH2COOH, 18-23 mol %] by day 90 and day 176 in two separate studies. 8:2 FTOH was transformed by day 181 to 8:2 FTCA (18 mol %), 8:2 FTUCA (5.1 mol %), and 7:3 acid (27 mol %). 6:2 and 8:2 FTOH anaerobic biotransformation led to low levels of perfluorohexanoic acid (PFHxA, ≤0.4 mol %) and perfluorooctanoic acid (PFOA, 0.3 mol %), respectively. 6:2 FTUCA anaerobic biotransformation led to a newly identified novel transient intermediate 3-fluoro 5:3 acid [F(CF2)5CFHCH2COOH] and 5:3 acid, but not 5:2 sFTOH [F(CF2)5CH(OH)CH3] and α-OH 5:3 acid [F(CF2)5CH2CH(OH)COOH], two precursors leading to PFPeA (perfluoropentanoic acid) and PFHxA. Thus, FTOH anaerobic biotransformation pathways operated by microbes in the environment was likely inefficient at shortening carbon chains of FTOHs to form PFCAs (perfluorinated carboxylic acids). These results imply that anaerobic biotransformation of FTOH-based products may produce polyfluorinated acids, but is not likely a major source of PFCAs detected in anaerobic environmental matrices such as anaerobic digester sludge, landfill leachate, and anaerobic sediment under methanogenic conditions.

Kinetics of 8-2 fluorotelomer alcohol and its metabolites, and liver glutathione status following daily oral dosing for 45 days in male and female rats

Fluorotelomer alcohols (FTOHs) are raw materials used in the manufacture of polymeric and surfactant products. Based on previous findings from single oral dosing in rats with radiolabeled 8-2 FTOH, glutathione (GSH) depletion and/or the presence of perfluorinated/polyfluorinated acids and aldehyde metabolites was hypothesized to account for the hepatocellular lesions observed in male rats from a 90-day subchronic oral dosing study. Further, the reported nephropathy in female rats from the subchronic experiment was hypothesized to have been initiated by a thiol metabolite produced by degradation of GSH conjugates. In the current investigation, the kinetics of 8-2 FTOH and its metabolites along with liver GSH status were evaluated in the rat following daily oral dosing with 8-2 FTOH for 45 days at 5 and 125 mg/kg/day. Liver GSH stores 1-2h after dosing were unaffected, suggesting that GSH depletion is not likely a relevant mode of action in the liver. The tissue metabolite data indicate that the liver toxicity mode of action is likely associated with elevated levels of perfluoroalkyl acids found in males, since other polyfluorinated metabolites and 8-2 FTOH were present in livers from female rats at comparable or higher levels. Detection of the N-acetyl cysteine conjugate of the unsaturated parent telomer alcohol in urine from female rats and not male rats provides some evidence to support the mechanistic basis for the observed kidney effects. Further, the increasing levels of perfluorooctanoic acid (PFOA) in plasma from female rats over the 45-day dosing phase, while unexpected, may reflect an increased net absorption of 8-2 FTOH, slow elimination of intermediates in the metabolic pathway between 8-2 FTOH and PFOA, or altered kidney clearance. The results of this study have enhanced our understanding of 8-2 FTOH kinetics and metabolism and potential modes of action in the rat, which will guide the design of future studies for FTOHs and our need to define the mechanistic basis for the observed effects.

Determination of extractable perfluorooctanoic acid (PFOA) in water, sweat simulant, saliva simulant, and methanol from textile and carpet samples by LC/MS/MS

Methods were developed to quantify the amount of perfluorooctanoic acid (PFOA) extracted from textile and carpet samples through contact with water, methanol, and sweat and saliva simulants using LC/MS/MS. The limit of quantitation (LOQ) for samples extracted in water and sweat simulant is 1 ppb (ng PFOA (g sample)(-1)) while the limits of quantitation for samples extracted in saliva simulant and methanol were 3 ppb and 2.5 ppb, respectively. Method validation results are provided for a polyester control textile sample that was extracted in water on two different days by different analysts, which gave an overall recovery of 103% and standard deviation of 5.3% for 30 analyses. However, for routine application of these methods to a large number of sample sets differing in chemical and physical compositions, a complete validation for each sample type is not practical or possible since control samples for fortifications are often not available. Instead, suitable analytical methods and acceptance criteria are described which ensure accurate PFOA quantitation in each of the solvent extract types. During routine use of these methods, post-extraction spike recoveries for the different sample types and solvents are 100 +/- 15% using a dual isotopically labeled (13)C-PFOA internal standard to correct for matrix effects. A comparison of extraction solvent versus time using a wrist action shaker for textile and carpet samples demonstrates that the total extractable amount of PFOA is similar for each of the solvent types. However, as expected the rate of extraction in water and simulants is significantly less than that of methanol. Finally, a comparison of 2 h and 24 h wrist action shaker extractions with a 1.5 h pressurized fluid extraction (PFE) in methanol reveals that the 24 h wrist action shaker yields the highest results. The 2 h wrist action shaker results are similar to those of the 1.5 h PFE extraction.

Chromatographic Investigation of Dyes Extracted from Coptic Textiles from the National Museum in Warsaw

Abstract This work aimed to identify natural dyes in extracts from Coptic fibres. The objects examined originate from fourth- to twelfth-century AD Egypt. Chromatographic separations of all the samples were carried out using reversed-phase HPLC (high performance liquid chromatography) with UV-Vis detection and fluorescence detection. Fluorescence detection proved to be better than UV-Vis diode array detection for the determination of some compounds. Selected samples were analysed with HPLC-MS (HPLC-mass spectroscopy) which confirmed the LC-UV findings and allowed the detection and identification of additional compounds. Most of the dyes mentioned in the literature as having been used by Copts were detected: Armenian cochineal, flavonoid yellow dyes, indigotin, lac dye, madder and tannins. Some new compositions of significant colours were also discovered, which had not been reported previously in Coptic textiles. Elemental analysis using SEM-EDS (scanning electron microscopy–energy dispersive spectroscopy) was performed to identify mordants.

Biotransformation of 6:2 Fluorotelomer Alcohol (6:2 FTOH) by a Wood-Rotting Fungus

Biotransformation of 6:2 FTOH [F(CF2)6CH2CH2OH] by the white-rot fungus, Phanerochaete chrysosporium, was investigated in laboratory studies. 6:2 FTOH is a raw material increasingly being used to replace products that can lead to long-chain perfluoroalkyl carboxylic acids (PFCAs, ≥ 8 carbons). During a products life cycle and after final disposal, 6:2 FTOH-derived compounds may be released into the environment and potentially biotransformed. In this study, P. chrysosporium transformed 6:2 FTOH to perfluorocarboxylic acids (PFCAs), polyfluorocarboxylic acids, and transient intermediates within 28 days. 5:3 Acid [F(CF2)5CH2CH2COOH] was the most abundant transformation product, accounting for 32-43 mol % of initially applied 6:2 FTOH in cultures supplemented with lignocellulosic powder, yeast extract, cellulose, and glucose. PFCAs, including perfluoropentanoic (PFPeA) and perfluorohexanoic (PFHxA) acids, accounted for 5.9 mol % after 28-day incubation. Furthermore, four new transformation products as 6:2 FTOH conjugates or 5:3 acid analogues were structurally confirmed. These results demonstrate that P. chrysosporium has the necessary biochemical mechanisms to drive 6:2 FTOH biotransformation pathways toward more degradable polyfluoroalkylcarboxylic acids, such as 5:3 acid, with lower PFCA yields compared to aerobic soil, sludge, and microbial consortia. Since bacteria and fungi appear to contribute differently toward the environmental loading of FTOH-derived PFCAs and polyfluorocarboxylic acids, wood-rotting fungi should be evaluated as potential candidates for the bioremediation of wastewater and groundwater contaminated with fluoroalkyl substances.

Aerobic Soil Biotransformation of 6:2 Fluorotelomer Iodide

6:2 FTI [F(CF2)6CH2CH2I] is a principal industrial raw material used to manufacture 6:2 FTOH [F(CF2)6CH2CH2OH] and 6:2 FTOH-based products and could enter aerobic environments from possible industrial emissions where it is manufactured. This is the first study to assess 6:2 FTI aerobic soil biotransformation, quantify transformation products, and elucidate its biotransformation pathways. 6:2 FTI biotransformation led to 6:2 FTOH as a key intermediate, which was subsequently biotransformed to other significant transformation products, including PFPeA [F(CF2)4COOH, 20 mol % at day 91], 5:3 acid [F(CF2)5CH2CH2COOH, 16 mol %], PFHxA [F(CF2)5COOH, 3.8 mol %], and 4:3 acid [F(CF2)4CH2CH2COOH, 3.0 mol %]. 6:2 FTI biotransformation also led to a significant level of PFHpA [F(CF2)6COOH, 16 mol % at day 91], perhaps via another putative intermediate, 6:2 FTUI [F(CF2)6CH ═ CHI], whose molecular identity and further biotransformation were not verified because of the lack of an authentic standard. Total recovery of the aforementioned per- and polyfluorocarboxylates accounted for 59 mol % of initially applied 6:2 FTI by day 91, in comparison to 56 mol % when soil was dosed with 6:2 FTOH, which did not lead to PFHpA. Thus, were 6:2 FTI to be released from its manufacture and undergo soil microbial biotransformation, it could form PFPeA, PFHpA, PFHxA, 5:3 acid, and 4:3 acid in the environment.