Abstract  A novel series of linear, high-molecular-weight polymers was synthesized by one-pot, superacid-catalyzed reaction of pentafluorobenzaldehyde (PFBA) (1) with nonactivated aromatic hydrocarbons: biphenyl, dipheryl ether, p-terphenyl, 4,4'-diphenoxybenzophenone, and 1,3-bis- and 1,4-bis(4'-phenoxybenzoyl)benzenes. The reactions were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride. The polymer-forming reaction was highly dependent upon the acidity of the reaction medium, as judged from the molecular weights of the polymers obtained. A possible reaction mechanism is suggested. The polymers obtained were soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. H-1 and C-13 NMR analyses of the polymers synthesized revealed their linear structure. The pendent pentafluorophenyl groups react regioselectively with nucleophiles under basic conditions in polar, aprotic solvents. Side-chain-type sulfonated polymers were obtained from reaction with sodium 4-hydroxybenzenesulfonate.

Abstract  A pre-sampling isotope dilution-direct injection-liquid chromatography tandem mass spectrometry (DI-LC/MS/MS) analytical method for the analysis of perfluorinated compounds (PFCs) in water is presented. This pre-sampling isotope dilution method incorporates stable isotope internal standards (ISs) and surrogate recovery standards (SRSs) added to sample bottles prior to sample collection. Pre-sampling isotope dilution corrects for PFC adsorption losses and enables a simple quantitative DI-LC/MS/MS water method with a 28 day sample holding time. Method analytes include perfluorinated carboxylic acids (PFCAs) (C4-C12), perfluorinated sulfonic acids (PFSAs) (C4, C6, and C8), perfluorooctane sulfonamide (PFOSA), and four SRSs ([2,3,4-C-13(3)]PFBA, [1,2,3,4-C-13(4)]PFOA, [1,2,3,4-C-13(4)]PFOS, and [1,2-C-13(2)]PFUnA). At 28 day sample holding times, mean recoveries of laboratory reagent water samples (Milli-Q (TM) water containing hardness at 165 mg equivalent CaCO3 L-1) fortified with the PFC method analytes at 0.2-40 ng mL(-1) (0.1-1 ng mL(-1) SRSs) are 94.9-115% with relative standard deviations of 0.97-7.9%. At 28 day sample holding times in fortified laboratory reagent water samples, single laboratory lowest concentration minimum reporting levels of 0.010-0.020 ng mL(-1) (0.075 ng mL(-1) PFBA) are demonstrated for method analytes and SRSs. Method applications to synthetic chlorinated drinking water samples and three environmental sample matrices are presented that demonstrate method ruggedness. Mean recoveries of synthetic chlorinated drinking water samples fortified with the PFC method analytes at 0.1-10 ng mL(-1) and SRSs at 0.1-1 ng mL(-1) are 97.8-113% with relative standard deviations of 2.0-18%. Mean recoveries and relative standard deviations in environmental groundwater samples, production facility non-contact cooling water effluent samples, and production facility wastewater treatment effluent samples fortified with the PFC method analytes at 0.25-2.5 ng mL(-1), 0.25-10 ng mL(-1), 0.25-50 ng mL(-1) respectively and SRSs at 0.1 ng mL(-1) are 100 +/- 7.7% (RSD +/- 12%, PFBA +/- 23%), 100 +/- 5.5% (RSD +/- 11%), 100 +/- 5.2% (RSD +/- 11%) respectively. Excellent method correlation was obtained with USEPA Method 537 in a comparative analysis of synthetic chlorinated drinking water samples aged 7 days and fortified with C6-C12 PFCAs and C4, C6, and C8 PFSAs, and three SRSs [C-13(4)] PFOA, [C-13(2)] PFUnA, and [C-13(4)] PFOS at 0.1 ng mL(-1). The average absolute difference between the EPA Method 537 and DI-LC/MS/MS measurements for the method analytes and SRSs was 8%.

Abstract  Over the years several methodologies have been developed for the structural analysis of naturally occurring sialic acids (Sias), a family with more than 62 members. Currently there are two primary instrumental approaches: analysis of volatile Sia derivatives by gas-liquid chromatography (GLC) combined with electron-impact mass spectrometry (EI/MS), and analysis of fluorescently labeled Sias by high-performance liquid chromatography (HPLC) eventually coupled with electrospray mass spectrometry (ESI/MS). This chapter presents both approaches in detail. The volatile Sia derivatives are comprised of trimethylsilylated methyl ester derivatives, heptafluorobutylated methyl ester derivatives, or pertrimethylsilylated derivatives. The fluorescent Sia derivatives are prepared by reaction with 1,2-diamino-4,5-methylenedioxybenzene. For the identification of the different Sia derivatives, detailed GLC, HPLC, EI/MS, and ESI/MS data are included.

Abstract  We have developed a new method for the simultaneous measurements of stable isotopic tracer enrichments and concentrations of individual long-chain fatty acyl-carnitines in muscle tissue using ion-pairing high-performance liquid chromatography-electrospray ionization quadrupole mass spectrometry in the selected ion monitoring (SIM) mode. Long-chain fatty acyl-carnitines were extracted from frozen muscle tissue samples by acetonitrile/methanol. Baseline separation was achieved by reverse-phase HPLC in the presence of the volatile ion-pairing reagent heptafluorobutyric acid. The SIM capability of a single quadrupole mass analyzer allows further separation of the ions of interest from the sample matrixes, providing very clean total and selected ion chromatograms that can be used to calculate the stable isotopic tracer enrichment and concentration of long-chain fatty acyl-carnitines in a single analysis. The combination of these two separation techniques greatly simplifies the sample preparation procedure and increases the detection sensitivity. Applying this protocol to biological muscle samples proves it to be a very sensitive, accurate, and precise analytical tool.

Abstract  Efficient chromatographic separation is a prerequisite for the sensitive analysis of complex peptide mixtures using liquid chromatography-mass spectrometry. This is especially true for the analysis of mixtures of unmodified and posttranslationally modified peptides, for example, phosphorylated peptides in the presence of their unmodified analogues. Applying monolithic capillary columns based on poly(styrene/divinylbenzene), the influence of acidic eluents based on trifluoroacetic and heptafluorobutyric acid as well as an alkaline eluent based on triethylamine-acetic acid (pH 9.2) on the separation of synthetic phosphopeptides was evaluated. Heptafluorobutyric acid offered the longest retention times and highest selectivities and, hence, the most effective separation. Application of the alkaline eluent in conjunction with detection in negative ion mode electrospray ionization mass spectrometry, on the other hand, allowed the detection of phosphorylated peptides with significantly lower limits of detection, as compared to acidic eluents in combination with detection in positive ion mode. Pairs of phosphorylated and nonphosphorylated synthetic peptides, ranging from 7- to 16-mers, as well as phosphorylated peptides form a tryptic protein digest could be separated both at acidic and alkaline pH. Utilizing a 60 x 0.20-mm-i.d. capillary column, the limit of detection in negative ion detection mode for a 4-fold phosphorylated peptide in a beta-casein digest was 10 fmol. Together with the capability for fast separation of protein digests, monolithic columns, thus, facilitate the effective and sensitive analysis of this important posttranslational modification.

Abstract  We present a new candidate reference method for determining cortisol in serum. The method is based on isotope dilution-gas chromatography/mass spectrometry and makes use of derivatization with heptafluorobutyric anhydride and selected ion monitoring at m/z 489 and 491. A detection limit of 0.08 pmol (30 pg) was achieved. Twenty-four structurally related steroids were tested for interference and found negative. Verification of the analytical quality specifications was done from measurement in two laboratories of the certified reference materials 192 and 193 of the Bureau Communautaire de Référence and a number of commercial quality control materials. The maximum systematic error was estimated to be 1.0% and the mean imprecision was 1.0%. The total error was lower than 2.05%. The method was applied for target-setting in external quality assessment and internal accuracy control and for measurement of patient samples.

Abstract  Rats were treated for 5 to 14 days with perfluoroacetate, perfluorobutyrate and perfluorooctanoate. Alterations in hepatic morphology with special reference to the peroxisomal compartment were investigated by light and electron microscopy following cytochemical staining of catalase activity with the alkaline 3,3'-diaminobenzidine medium. All three compounds induced hepatomegaly and peroxisome proliferation. Perfluorobutyrate and perfluorooctanoate were found to be more active than perfluoroacetate. Perfluorooctanoate-induced peroxisome proliferation was more prevalent in centrilobular than in periportal hepatocytes. Peroxisomes in centrilobular liver cells frequently were of round shape, exhibited diameters of up to 1.5 microns and were predominantly located within smooth endoplasmic reticulum-glycogen areas. In periportal cells, however, clusters of polymorphous peroxisomes ranging from 250 to 1,100 nm in diameter were observed at the periphery of smooth endoplasmic reticulum-glycogen regions. Peroxisome proliferation was accompanied by a change of peroxisomal and mitochondrial enzyme activities, in particular an increase in peroxisomal palmitoyl-CoA oxidation. Significant alterations in the concentration of peroxisomal matrix and membrane polypeptides were also noted. Within the first 2 days, perfluorooctanoate treatment exerted a strong hypolipidemic activity and both compounds perfluorooctanoate and perfluorobutyrate raised the level of hepatic free acid-soluble CoA nearly 10-fold as compared with control livers. The results suggest perfluorinated carboxylic acids to be model substances suitable to correlate biochemical and morphological parameters with the zonal heterogeneity of the peroxisomal compartment in rat liver. Due to the manifold hepatic effects, contact of humans with perfluorinated carboxylic acids or their metabolic precursors may represent a severe health risk.

Abstract  A novel mobile phase containing heptafluorobutyric acid has been used for ion-interaction high-performance liquid chromatography of leukotrienes, lipoxins and related compounds on octadecylsilane silica columns. The use of a hydrophobic perfluorinated carboxylic acid as an ion-interaction agent at optimized concentration and pH permitted rapid, isocratic separation of leukotrienes, lipoxins and monohydroxyeicosatetraenoic acids. A completely volatile mobile phase suitable for preparative chromatography was obtained by using triethylamine as the base for pH adjustment. With this novel mobile phase, leukotrienes and monohydroxyeicosatetraenoic acids were completely separated in less than 15 min.

Abstract  A method for the analysis of deoxynivalenol (DON) und nivalenol (NV) in cereals is described. This method is suitable for routine use for control purposes. The extract is purified on a florisil column. Derivatization with heptafluorobutyrylimidazole is followed by quantitative determination by means of capillary gas chromatography and electron capture detection (ECD). For verification purposes two-dimensional thin layer chromatography is applied to gc-positive extracts. 67 cereal samples and cereal products from the Berlin market place have been assayed. Depending on the type of sample the limit of detection was 20 to 30 micrograms/kg for DON, and 100 to 300 micrograms/kg for NV.

Abstract  The induction of peroxisome proliferation in rat liver was examined after administration of perfluoro-n-decanoic acid (PFDA, C10), perfluoro-n-octanoic acid (PFOA, C8), perfluoro-n-butyric acid (PFBA, C4), 1-H,1-H-pentadecafluoro-n-octanol (PFOL, C8) perfluorododecane (PFD, C12), and perfluorooctane (PFO, C8). The peroxisome proliferation in the liver was detected by the following methods; 1) measurement of liver weight, 2) assay of hepatic catalase activity, 3) analysis of 600 X g supernatant of liver homogenates by SDS-polyacrylamide gel electrophoresis to observe the induction of the bifunctional enoyl-CoA hydratase in peroxisomes (80K-protein) and 4) observation by electron microscopy. The oral administration of powdered chow containing 0.02%-PFOA and PFBA to male rats of the Sprague-Dawley strain for 2 weeks and the single intraperitoneal injection of corn oil mixed with PFDA, PFOA, and PFOL at the dose of 100 mg/kg induced peroxisome proliferation markedly. PFOL, which has two hydrogen atoms around the hydroxylated carbon, should be metabolized to PFOA, which is an active inducer. Perfluorinated paraffins, PFD and PFO, did not show any induction, indicating the importance of the carboxylic group in the molecule for the peroxisome proliferation. Although the participation of thyroid hormone cannot be excluded, PFOA appears to act directly on the liver.

Abstract  This paper describes the derivation and use of predictive retention coefficients for the reversed-phase high-performance liquid chromatography of peptides. The use of predicted elution positions in the isolation of peptides is illustrated by two examples where peptides, whose existence was postulated from cDNA sequence data, have been successfully isolated. The combination of the powerful chromatographic technology and the ability to predict the elution positions of peptides based on their composition provides a very potent method for the isolation of peptides from biological tissues. © 1982.

Abstract  The Integrated Risk Information System (IRIS) is a program within the US Environmental Protection Agency (EPA) that is responsible for developing toxicologic assessments of environmental contaminants. An IRIS assessment contains hazard identifications and dose-response assessments of various chemicals related to cancer and noncancer outcomes. Although the program was created to increase consistency among toxicologic assessments within the agency, federal, state, and international agencies and other organizations have come to rely on IRIS assessments for setting regulatory standards, establishing exposure guidelines, and estimating risks to exposed populations. Over the last decade, the National Research Council (NRC) has been asked to review some of the more complex and challenging IRIS assessments, including those of formaldehyde, dioxin, and tetrachloroethylene. In 2011, an NRC committee released its review of the IRIS formaldehyde assessment. Like other NRC committees that had reviewed IRIS assessments, the formaldehyde committee identified deficiencies in the specific assessment and more broadly in some of EPA's general approaches and specific methods. Although the committee focused on evaluating the IRIS formaldehyde assessment, it provided suggestions for improving the IRIS process and a roadmap for its revision in case EPA decided to move forward with changes to the process. Congress directed EPA to implement the report's recommendations and then asked the National Research Council to review the changes that EPA was making (or proposing to make) in response to the recommendations. Review of EPA's Integrated Risk Information System (IRIS) Process provides an overview of some general issues associated with IRIS assessments. This report then addresses evidence identification and evaluation for IRIS assessments and discusses evidence integration for hazard evaluation and methods for calculating reference values and unit risks. The report makes recommendations and considerations for future directions. Overall, Review of EPA's Integrated Risk Information System Process finds that substantial improvements in the IRIS process have been made, and it is clear that EPA has embraced and is acting on the recommendations in the NRC formaldehyde report. The recommendations of this report should be seen as building on the progress that EPA has already made.

Abstract  A simple gas chromatographic (GC) method has been developed to determine 2,4- and 2,6-diaminotoluenes in polyurethane foam. Diaminotoluenes were reacted with heptafluorobutyric anhydride in toluene, and the products, bis-heptafluorobutyrates, were determined by GC, using a 3% silicone OV-330 column. The 2,4- and 2,6-diaminotoluenes can be detected as heptafluorobutyryl derivatives by using an electron capture detector at levels of 5 and 2 pg, respectively. Finally, 2.7-3.0 micrograms/g of 2,4- and 1.3-1.9 micrograms/g of 2,6-diaminotoluene were detected in 3 commercial polyurethane foams.

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  Surface CO and ozone data were obtained in 1998 at Happo (36.7degreesN. 137.8degreesE, altitude 1840 in) in Japan. Backward trajectory analysis was applied to get the origin of the air mass to the measuring site. The air mass is basically coming from the west over the Asian continent except during summer. A maritime air mass prevails in the summertime, due to a dominant high-pressure system in the Pacific. In most cases, the air mass from the west (from China and Korea) shows a higher CO concentration than the air mass from the north, and the air mass from the Pacific shows the lowest CO concentration, Forest fires in Siberia were highly enhanced in 1998. To assess the influence of these forest fires, air masses from Siberia (from the North/Northwest direction) are divided into two categories: those that passed over the forest-fire region in Siberia and those that did not. This is done using AVHRR/NOAA satellite data and isentropic backward trajectories. The average CO concentration difference between these two categories is about 30ppbv in May. Similar analysis for ozone data also shows concentrations about 7 ppbv higher for the air masses that passed over the forest-fire region in Siberia. These results suggest that air pollutants emitted by forest fires in Siberia in 1998 could be transported and influence the air at Happo in springtime. (C) 2002 Elsevier Science Ltd. All rights reserved.

Abstract  Many goitrogenic xenobiotics that increase the incidence of thyroid tumors in rodents exert a direct effect on the thyroid gland to disrupt one of several possible steps in the biosynthesis, secretion, and metabolism of thyroid hormones. This includes (a) inhibition of the iodine trapping mechanism, (b) blockage of organic binding of iodine and coupling of iodothyronines to form thyroxine (T4) and triiodothyronine (T3), and (c) inhibition of thyroid hormone secretion by an effect on proteolysis of active hormone from the colloid. Another large group of goitrogenic chemicals disrupts thyroid hormone economy by increasing the peripheral metabolism of thyroid hormones through an induction of hepatic microsomal enzymes. This group includes central nervous system-acting drugs, calcium channel blockers, steroids, retinoids, chlorinated hydrocarbons, polyhalogenated biphenyls, and enzyme inducers. Thyroid hormone economy also can be disrupted by xenobiotics that inhibit the 5'-monodeiodinase that converts T4 in peripheral sites to biologically active T3. Inhibition of this enzyme by FD&C Red No. 3 lowers circulating T3 levels, which results in a compensatory increased secretion of thyroid stimulating hormone (TSH), follicular cell hypertrophy and hyperplasia, and an increased incidence of follicular cell tumors in 2-yr or lifetime studies in rats. Physiologic perturbations alone, such as the feeding of an iodine-deficient diet, partial thyroidectomy, natural goitrogens in certain foods, and transplantation of TSH-secreting pituitary tumors in rodents also can disrupt thyroid hormone economy and, if sustained, increase the development of thyroid tumors in rats. A consistent finding with all of these goitrogens, be they either physiologic perturbations or xenobiotics, is the chronic hypersecretion of TSH, which places the rodent thyroid gland at greater risk to develop tumors through a secondary (indirect) mechanism of thyroid oncogenesis associated with hormonal imbalances.

Abstract  This publication originates from a workshop held in 1997 to consider how rodent tumours of urinary bladder, renal cortex, and thyroid gland should be treated within the IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. The workshop also addressed the predictive value of these tumours for the identification of carcinogenic hazards to humans when they occur alone and when they occur along with tumours in other organs. In the following sections, etiological risk factors in humans and experimental animals as well as the hypotheses underlying the proposed species-specific mechanisms for each of the above-mentioned tumour types are summarized. Finally, for each tumour type, recommendations are presented on how the mechanistic data could be used in the overall evaluation of carcinogenicity to humans.

Abstract  Epidemiological studies from both iodine-sufficient and -deficient human populations strongly suggest that early maternal hypothyroxinemia (i.e., low circulating free thyroxine before onset of fetal thyroid function at midgestation) increases the risk of neurodevelopmental deficits of the fetus, whether or not the mother is clinically hypothyroid. Rat dams on a low iodine intake are hypothyroxinemic without being clinically hypothyroid because, as occurs in pregnant women, their circulating 3,5,3'-triiodothyronine level is usually normal. We studied cell migration and cytoarchitecture in the somatosensory cortex and hippocampus of the 40-day-old progeny of the iodine-deficient dams and found a significant proportion of cells at locations that were aberrant or inappropriate with respect to their birth date. Most of these cells were neurons, as assessed by single- and double-label immunostaining. The cytoarchitecture of the somatosensory cortex and hippocampus was also affected, layering was blurred, and, in the cortex, normal barrels were not formed. We believe that this is the first direct evidence of an alteration in fetal brain histogenesis and cytoarchitecture that could only be related to early maternal hypothyroxinemia. This condition may be 150-200 times more common than congenital hypothyroidism and ought to be prevented both by mass screening of free thyroxine in early pregnancy and by early iodine supplementation to avoid iodine deficiency, however mild.

Abstract  Peroxisome proliferator-activated receptor gamma (PPARgamma) belongs to a superfamily of thyroid / steroid hormone receptors and regulates transcription of their target genes in a ligand-dependent manner. Recently, PPARgamma was reported to be expressed in several cell lines derived from breast, colon, stomach and lung cancers. Activation of PPARgamma by its ligand inhibits the growth of these tumor cells, suggesting that PPARgamma ligand is a potential anti-cancer agent in PPARgamma-expressing tumors. However, its expression in brain tumors has not been studied. We thus studied the expression in glioma samples with different pathological stages from 20 patients. It was demonstrated that 95% of the glioma tissue expressed PPARgamma mRNA. The results prompted us to study whether PPARgamma ligand affects the growth of cell lines derived from brain tumors. The receptor expression was studied in 9 cell lines either derived from malignant glioma or neuroblastoma. The expression was detected in a glioma cell line SK-MG-1 and in a neuroblastoma cell line NB-1. Addition of one of the PPARgamma ligands, troglitazone, induced growth inhibition in both cell lines. Further analyses revealed that this growth inhibition is caused by a PPARgamma-mediated induction of apoptosis. These results suggest that PPARgamma ligands could be a potential therapeutic agent for the treatment of the brain tumors expressing this receptor.

Abstract  The biodegradability of several potential endocrine disrupting compounds, namely 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), bisphenol A (BPA), triclosan (TCS), di-(2-ethylhexyl)-phthalate (DEHP), perfluorooctanoate (PFOA) and perfluorononanoate (PFNA) was evaluated in this study, using OECD method 301F (manometric respirometry test) and activated sludge as inoculum. According to the results, 4-n-NP and BPA meet the strict definition of ready biodegradability and they are not expected to be persistent during the activated sludge process. Partial biodegradation was observed for DEHP (58.7+/-5.7%, n=3), TCS (52.1+/-8.5%, n=3) and NP1EO (25.9+/-8.1%, n=3), indicating their possible biodegradation in wastewater treatment systems, while no biodegradation was observed for NP2EO, PFOA and PFNA. Experiments in the co-presence of a readily biodegradable compound showed the absence of co-metabolic phenomena during 4-n-NP, BPA and TCS biodegradation. Using first order kinetics to describe biodegradation of the target compounds, half-lives of 4.3+/-0.6, 1.3+/-0.2, 1.8+/-0.5, 6.9+/-2.6 days were calculated for 4-n-NP, BPA, TCS and DEHP, respectively. Toxicity tests using marine bacterium Vibrio fischeri showed that biodegradation of 4-n-NP, NP1EO, BPA and TCS is a simultaneous detoxification process, while possible abiotic or biotic transformations of NP2EO, DEHP, PFOA and PFNA during respirometric test resulted to significant increase of their toxicities.

Abstract  The Updated Tables, February 2015 provides nationally representative biomonitoring data that have become available since the publication of the Fourth National Report on Human Exposure to Environmental Chemicals, 2009. The Updated Tables, February 2015 presents recently released data from NHANES 2005-2006, 2007-2008, 2009-2010, and 2011-2012 and also NHANES 2005-2006 and 2007-2008 pooled samples using the corrected NHANES sampling weights.

Abstract  To clarify the mechanism of induction of hepatic peroxisome-associated enzymes by drugs, we examined the interrelationship between the structures of fifteen drugs of two types (phenoxyacetic acid derivatives and perfluorinated compounds) and their inducing activities. Male Wistar rats were given the drugs at 150 mg/kg body weight daily for 2 weeks, and then hepatic activities of fatty acid metabolism-related enzymes were determined. The activity of the cyanide-insensitive fatty acyl-CoA oxidizing system located in peroxisomes was increased significantly in the following order: 2,4,5-trichlorophenoxypropionic acid (12.5-fold) greater than 2,4-dichlorophenoxypropionic acid (6.6-fold) greater than clofibrate (4.5-fold) greater than 2-methyl-4-chlorophenoxyacetic acid (2.6-fold) greater than 2,4,5-trichlorophenoxyacetic acid (2.5-fold) greater than p-chlorophenoxypropionic acid (2.4-fold) greater than 2,4-dichlorophenoxyacetic acid (1.7-fold). Treatment with perfluorinated compounds, perfluorobutyric acid, perfluorooctanoic acid, perfluorodecanoic acid and perfluorooctanol, also induced the activity by 2-, 4.3-, 3.1- and 2.0-fold respectively. The profile of the induction of carnitine acetyltransferase by these compounds was quite similar to that of cyanide-insensitive fatty acyl-CoA oxidizing system. Lipophilicity of these drugs was determined by the octanol-water partition method. Among these drugs, 2,4,5-trichlorophenoxypropionic acid showed the largest octanol/water partition coefficient (log P = 0.39). These results show a strong correlation among the number of chlor-substitutions on the phenyl moiety, the methyl-group on the alpha position of the acetic acid moiety, lipophilicity and the inducibility of peroxisomal fatty acid oxidation-related enzymes.

Abstract  In this study, perfluoroalkyl substances (PFASs) and the isomers of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) were analyzed in fresh snow samples collected from 19 cities in northern China, 2013. The levels of total PFASs in the snow samples were 33.5-229ng/L, suggesting heavy atmospheric pollution of PFASs in northern China. PFOA (9.08-107ng/L), PFOS (3.52-54.3ng/L), perfluoroheptanoate (PFHpA) (3.66-44.8ng/L), and perfluorohexanoate (PFHxA) (3.21-23.6ng/L) were predominant with a summed contribution of 82% to the total PFASs. The particulate matters (PMs) associated PFASs contributed 21.5-56.2% to the total PFASs in the snow, suggesting PMs are vital for the transport and deposition of airborne PFASs. Partitioning of PFASs between PM and dissolved phases was dependent on the carbon chain length and end functional groups. Isomer profiles of PFOA and PFOS in the snow were in agreement with the signature of the historical 3M electrochemical fluorination (ECF) products, suggesting that the ECF products were still produced and used in China. Further source analysis showed that the airborne PFASs in urban area were mainly due to direct release rather than degradation of their precursors.