The Relationship Between Perfluoroalkyl Substances Concentrations and Thyroid Function in Early Childhood: A Prospective Cohort Study

Background: Exposure to perfluoroalkyl substances (PFAS) has been suggested to affect thyroid function; however, data on early-life exposure and thyroid function in early childhood are scarce. We investigated the cross-sectional and longitudinal relationships of early-life exposure to PFAS with thyroid function at 2, 4, and 6 years of age. Methods: This study used data on PFAS exposure and thyroid function from the Environment and Development of Children (EDC) cohort study. A total of 660 children who visited at least once at 2, 4, or 6 years of age (381 children aged 2 years, 569 children aged 4 years, and 511 children aged 6 years) were included in this study. Serum thyrotropin (TSH) levels were measured at 2, 4, and 6 years of age. The relationship of serum PFAS (sPFAS) concentrations with TSH levels at the three time points was assessed by repeated-measure analysis using linear mixed models. The serum levels of free thyroxine (fT4) and triiodothyronine (T3) were measured once (at 6 years of age). The relationship of sPFAS with fT4 and T3 levels at 6 years of age was investigated by linear regression analyses. Results: None complained of hyper- or hypothyroid symptoms with normal fT4 and T3 levels. Repeated-measure analysis showed that TSH levels at 2, 4, and 6 years of age were inversely associated with serum perfluorononanoic acid (sPFNA), after adjusting for age, sex, and/or dietary iodine intake (p < 0.05). When stratified by sex, TSH levels were inversely associated with serum perfluorooctanoic acid (sPFOA) in boys and sPFNA in girls (p < 0.05 for both). fT4 levels at 6 years of age were positively related to sPFNA and serum perfluorohexane sulfonic acid at 2 years of age and sPFOA at 6 years of age, and T3 levels at 6 years of age showed positive relationships with serum perfluorodecanoic acid and serum perfluorooctane sulfonic acid at 6 years of age (p < 0.05 for all). When stratified by sex, similar positive relationships for sPFAS with fT4 and T3 levels were significant among boys only. Conclusions: A significant relationship was found between early-life exposure to PFAS and thyroid function. Early-life exposure to PFAS was associated with decreased TSH and increased fT4 or T3 levels among preschool-age children.

Exposure to Perflouroalkyl acids and foetal and maternal thyroid status: a review

BACKGROUND

Exposure to perfluorinated-alkyl-acids (PFAAs) is ubiquitous. PFAAs are hormone-disrupting compounds that are strongly suspected to affect mother-child-health such as fetal growth. Thyroid disruption is a plausible mechanism of action. We aim to summarize the epidemiological evidence for the relation between prenatal and postnatal exposure to PFAAs and disruption of thyroid homeostasis in mothers and/or infants.

METHOD

Fifteen original publications on PFAAs concentrations and thyroid hormones (TH) in pregnant women and/or infants were found upon a literature search in the PubMed database. Information on exposure to seven PFAAs congeners [Perfluorooctane sulfonate (PFOS), Perfluorooctanoate (PFOA), Perfluorohexane sulfonate (PFHxS), Perfluorononanoic acid (PFNA), Perfluorodecanoic acid (PFDA), Perfluoroundecanoic acid (PFUnA), and Perfluorododecanoic acid (PFDoA)] and thyroid stimulating hormone (TSH), free and total thyroxine (FT4 and TT4), free and total triiodothyronine (FT3 and TT3), T3RU (Free triiodothyronine resin uptake) and FT4-index (FT4I) levels were recorded. We evaluated sampling of maternal TH by trimester, and infant TH by sex stratification. Reported associations between mother or infant PFAAs and TH were not uniformly assessed in the selected studies.

RESULTS

Ten out of the fifteen studies examined maternal PFAAs concentration and TSH level. Seven studies showed significant associations between TSH and exposure to six PFAAs congeners, most of them were positive. Maternal T4 and T3 were investigated in nine studies and five studies found inverse associations between exposure to six PFAAs congeners and TH (TT3, TT4, FT3, FT4 and FT4I) levels. Eight of the fifteen studies investigated PFAAs concentrations and infant TSH. Infant TSH level was significantly affected in four studies, positively in three studies. Nine studies investigated infant T4 and T3 and seven studies found significant associations with PFAAs exposure. However, both inverse and positive significant associations with infant TH were found eliciting no clear direction.

CONCLUSION

Results indicate a mainly positive relationship between maternal PFAAs concentrations and TSH levels, and suggestion of an inverse association with T4 and/or T3 levels. Associations of infant TH with PFAAs concentration were less consistent.

Perfluorinated Compounds (PFCs) in Soil of the Pearl River Delta, China: Spatial Distribution, Sources, and Ecological Risk Assessment

This study investigated the levels, spatial distribution, sources, and ecological risks of 16 perfluorinated compounds (PFCs) in 68 surface soil samples (0-20 cm) from 7 cities in the Pearl River Delta (PRD), China. Sixteen target PFCs, including perfluoroalkyl carboxylic acids (PFCAs, C₅-C₁₄, C₁₆, and C₁₈) and perfluoroalkyl sulfonic acids (PFSAs, C₄, C₆, C₈, and C₁₀), were analyzed by high-performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Concentrations of total PFCs (∑PFCs) ranged from 2.19 to 98.5 μg kg^-1 (dry weight, dw), with an average of 5.97 μg kg^-1 dw. Perfluorooctane sulfonate (PFOS) was the dominant PFC, accounting for 23.9% of ∑PFCs. The highest ∑PFCs was found in the soil sample collected from Dongguan with a large number of manufacturing industries. There were no significant differences of ∑PFCs among unban, industrial, and agricultural soils, indicating similar pollution sources in soil of the PRD. More than 70% of ∑PFCs in soil of the PRD could be attributed to the four principal components, represented by PFOS and perfluorooctanoic acid (PFOA), perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUdA). Ecological risk assessment indicated that PFOA had low risk to soil plants and animals. However, the risk of PFOS to soil plants was relatively high in some studied regions.

Impact of Extended Lactation on Fatty Acid Profile and Milk Composition of Dual Purpose Tropical Goat

BACKGROUND AND OBJECTIVE

Extended lactation has been implemented to increase milk yield in limited case. There is need further investigation in term of milk composition, fatty acid profile and milk flavour as recommendation for further implementation.

MATERIALS AND METHODS

The study lasted from July-September, 2017, used thirty lactating Etawah Crossbred goats in small farms of Sleman, Yogyakarta. Samples were collected from normal period and extended lactation which lasted for 2-3 months and longer than 10 months, respectively. The data on milk yield, composition, physical quality, fatty acids profile, sensory properties and nutrient consumption were measured on samples of 14 consecutive days. Assessments were done in Faculty of Animal Science and Integrated Research Laboratory, Universitas Gadjah Mada. Statistical analysis used ANOVA and Kruskal Wallis test and were processed with SPSS programme version 16.

RESULTS

Extended lactation did not affect milk yield and nutrient consumption of goat but caused higher content of milk fat, protein, total solid, acidity, caprylic, capric and total short-chain fatty acids in compared with normal lactation (p<0.05). The average values were 5.33, 4.40, 15.85, 0.30, 1.99, 9.10 and 12.13% vs. 3.75, 3.64, 13.55, 0.26, 1.69, 7.09 and 9.76% of total fatty acids in milk, respectively. Fatty acid profile did not associate with milk flavour.

CONCLUSION

Composition, acidity and short chain fatty acids content in milk of extended lactation were higher than in normal period but did not change milk flavour.

Perfluoroalkyl substances (PFASs) in air-conditioner filter dust of indoor microenvironments in Greece: Implications for exposure

The occurrence of perfluoroalkyl substances (PFASs) was for the first time investigated in various working microenvironments (internet cafes, electronics shops, coffee shops, restaurants, etc.) in Thessaloniki, Greece, using the dust trapped by central air conditioner (A/C) filters. Perfluorooctane sulfonic acid (PFOS) was found in the range from 16 to 227 ng g^-1, however it was detectable in only 30% of samples. On the contrary, perfluorohexanoic acid (PFHxA) was found in 85% of samples in the range from 3.6 to 72.5 ng g^-1, while 90-95% of samples exhibited perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDcA) and perfluorododecanoic acid (PFDoDA) in the range from 10-653 ng g^-1, 3.2-7.4 ng g^-1 and 3.8-13.1 ng g^-1, respectively. The PFAS profile varied largely among the different microenvironment categories suggesting different sources. Estimated daily intakes through dust ingestion were calculated.

Are perfluoroalkyl substances in water and fish from drinking water source the major pathways towards human health risk?

Due to potential adverse effects and bioaccumulation in biota and humans, perfluoroalkyl substances (PFASs) have raised wide attention in recent years. Ingestion is a vital pathway for PFASs to transmit to humans especially through water and fish. In present study, PFASs in water and fish from the drinking water source of Beijing in China were investigated. Three layers of water were collected in order to find the connection between concentrations of PFASs and depth of water, which showed no prominent correlation. PFASs in water from Miyun Reservoir with concentrations of 5.30-8.50 ng/L, were relatively lower compared with other reports on raw drinking water. Perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) were the dominant PFASs. In addition, six species of fish (including Cyprinus carpio, Carassius auratus, Erythroculter dabryi, Pseudohemiculter dispar, Hypophthalmichthys molitrix and Siniperca chuatsi) were analyzed, with concentrations of PFASs ranging from 1.70 to 14.32 ng/g wet weight (w.w.). Due to relatively stronger bioaccumulation potential, long chain perfluorinated carboxylates (PFCAs) and perfluorinated sulfonates (PFSAs) were detected with higher concentrations, especially perfluoroundecanoic acid (PFUdA) and perfluorodecanoic acid (PFDA). The estimated daily intake (EDI) of PFASs through drinking water and fish consumption were 0.20-0.34 and 3.44-12.61 ng/kg bw/day based on Exposure Factors Handbook of Chinese Population, respectively. In addition, the EDI of high-priority concern PFASs via pork, chicken and dust were also calculated, with value of 0.015-0.043, 0.003-0.013 and 0.074-0.390 ng/kg bw/day, respectively. The total EDI of PFOS and PFOA via diverse pathways were less than suggested tolerable daily intake (PFOS, 150 ng/kg bw/day; PFOA, 1500 ng/kg bw/day), indicating that the detected levels would not cause severe health effects on Beijing residents.

Occurrences, levels and risk assessment studies of emerging pollutants (pharmaceuticals, perfluoroalkyl and endocrine disrupting compounds) in fish samples from Kalk Bay harbour, South Africa

A comprehensive analysis of 15 target chemical compounds (pharmaceuticals and personal care product, perfluoroalkyl compounds and industrial chemicals) were carried out to determine their concentrations in selected commercially exploited, wild caught small and medium sized pelagic fish species and their organs (Thyrsites atun (snoek), Sarda orientalis (bonito), Pachymetopon blochii (panga) and Pterogymnus laniarius (hottentot)) obtained from Kalk Bay harbour, Cape Town. Solid phase extraction (SPE) method based on Oasis HLB cartridges were used to concentrate and clean-up the samples. Liquid chromatography-mass spectrometry analysis of these chemical compounds revealed the simultaneous presence of at least 12 compounds in different parts of the selected fish species in nanogram-per-gram dry weight (ng/g dw) concentrations. The results revealed that perfluorodecanoic acid, perfluorononanoic acid and perfluoroheptanoic acid were the most predominant among the perfluorinated compounds and ranged between: (20.13-179.2 ng/g), (21.22-114.0 ng/g) and (40.06-138.3 ng/g). Also, diclofenac had the highest concentration in these edible fish species out of all the pharmaceuticals detected (range: 551.8-1812 ng/g). The risk assessment values were above 0.5 and 1.0 for acute and chronic risk respectively which shows that these chemicals have a high health risk to the pelagic fish, aquatic organisms and to humans who consume them. Therefore, there is an urgent need for a precautionary approach and the adequate regulation of the use and disposal of synthetic chemicals that persist in aquatic/marine environment in this province and other parts of South Africa, to prevent impacts on the sustainability of our marine environment, livelihood and lives.

Accumulation of perfluoroalkyl substances in lysimeter-grown rice in Japan using tap water and simulated contaminated water

Perfluoroalkyl substances (PFASs) are a group of contaminants of concern in agricultural crops, but little is known of their accumulation or behavior in grains. We grew Japanese rice (Oryza sativa subsp. indica) in lysimeters irrigated with tap water or tap water plus simulated contaminated water for 2 years, then analyzed the roots, straw, unhulled rice, white rice, bran, soil, and water for PFASs residues. Total fluorine was measured by combustion ion chromatography. Estimated per-plant residue levels were 3.0 pg perfluorooctanesulfonic acid (PFOS) (bran: 0.5%, hull: 99.5%), 0.54 pg N-ethylperfluorooctanesulfonamide (N-EtFOSA) (white rice: 67%, hull: 33%), 1.2 pg perfluorobutanoic acid (PFBA) (white rice: 13%, bran: 7%, hull: 79%), 0.68 pg perfluoropentanoic acid (hull: 100%), 0.50 pg perfluorohexanoic acid (PFHxA) (white rice: 65%, bran: 16%, hull: 19%), 0.21 pg perfluoroheptanoic acid (hull: 100%), 0.25 pg perfluorooctanoic acid (PFOA) (hull: 100%), and 0.12 pg perfluorodecanoic acid (PFNA) (white rice: 81%, bran: 19%). Estimated daily PFASs intakes were <1-3 ng perfluorooctanesulfonamide, <1-7 ng N-EtFOSA, 1-2 ng PFBA, <3-4 ng PFHxA, and 1-2 ng PFNA. Estimated PFOS, PFOA, and total PFASs in straw feed were 0.4, 0.1, and 2 kg yr^-1 and 0.7, 0.4, and 8 kg yr^-1 in 2015 and 2016, respectively. Estimated PFOS, PFOA, and total PFASs in straw fertilizer were 4, 1, and 23 kg yr^-1 and 7, 4, and 86 kg yr^-1 in 2015 and 2016, respectively. PFASs accumulation may cause longer residence time in agricultural systems owing to straw being used as animal feed and organic fertilizer.

Does soil track-in contribute to house dust concentrations of perfluoroalkyl acids (PFAAs) in areas affected by soil or water contamination?

The Minnesota Department of Health measured levels of perfluoroalkyl acids (PFAAs) in house dust at homes in communities impacted by PFAA-contaminated soil and drinking water to determine whether PFAAs in soil outside the home are associated with concentrations in dust. House dust samples from both interior living spaces and entryways to the yard were collected and analyzed separately based on the presumption that PFAAs in entryway dust may better reflect "track-in" of PFAAs into the home from contaminated soil or lawns irrigated with contaminated water. PFAA detections and concentrations in living rooms were significantly higher compared to entryways; and concentrations in both sampling locations were higher than corresponding soil concentrations, suggesting that interior sources were the main contributors to PFAAs in house dust. PFAA dust concentrations in entryways were significantly associated with living room dust levels for all analytes except PFBA. Relationships between entryway dust and soil were only seen for one PFAA (PFOA). However, median concentrations of PFOA in entryway and living room dust were 35 and 70 times higher (respectively) than in soil, which highlights the lack of importance of PFAA soil track-in as a contributor to dust concentration in this setting. Due to the small sample size, larger scale studies are needed to further assess the potential for migration of PFAA contaminated soil to indoor dust.

Occurrence and partitioning behavior of perfluoroalkyl acids in wastewater effluent discharging into the Long Island Sound

Perfluoroalkyl acids (PFAAs) were measured in aqueous and suspended particulate matter (SPM) fractions in the final effluents from 12 wastewater treatment facilities located around the Connecticut shoreline. Aqueous phase concentrations ranged from 53 to 198 ng/L for ∑PFAAs with ≤7 perfluorinated carbons (CF₂) and 2-73 ng/L for >7 CF₂ PFAAs. Predominant PFAAs associated with effluent derived SPM were perfluorodecanoic acid and perflurorooctane sulfonic acid, detected in 48% and 52% of samples in concentrations ranging from <LOQ-1770 ng/g and <LOQ-2750 ng/g respectively. Based on the range of concentrations detected and the average flow of final effluent to the Long Island Sound (LIS), average total annual PFAA mass loads from wastewater treatment facilities to the LIS is estimated in the range of 70-315 kg/year, with 4-100 kg/year consisting of >7 CF₂ PFAAs. Partitioning coefficients (log K_OC) derived for effluent water and SPM phases (4.2 ± 0.3, 4.4 ± 0.4, 5.1 ± 0.2 and 5.3 ± 0.2 for PFOA, PFNA PFDA and PFUnA; 4.5 ± 0.2 and 5.2 ± 0.2 for PFOS and PFHsX respectively) were found to be of similar magnitude to aeration tank particles, though 0.5 to 2 log units greater than sludge solids and to natural system particulates including riverine SPM, estuarine SPM and sediments. Results from this study suggest that effluent derived suspended particulate matter could be an effective vector in the transport of long-chained PFAAs through wastewater treatment into receiving waters, and a potential vector to the local food chain.

Inter-individual, inter-city, and temporal trends of per- and polyfluoroalkyl substances in human milk from Swedish mothers between 1972 and 2016

Inter-individual, inter-city, and temporal trends of 19 per- and polyfluoroalkyl substances (PFASs) were investigated in human milk collected in Stockholm (1972-2016) and Gothenburg (2007-2015), Sweden. The concentrations of perfluorohexane sulfonate (PFHxS), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnDA), and perfluorotridecanoate (PFTrDA) in human milk from Stockholm increased significantly over the entire monitoring periods, whereas branched (Br) and linear (L) isomers of perfluorooctane sulfonamide (FOSA) decreased. In human milk from Gothenburg, significant downward trends were detected for perfluorododecanoate (PFDoDA), PFHxS and Br-perfluorooctane sulfonate (Br-PFOS) over the last decade. This declining trend was also observed for perfluorohexanoate (PFHxA), PFHxS, perfluorooctanoate (PFOA) and Br-PFOS in Stockholm over the same time period. No significant differences were observed in concentrations or relative PFAS profiles between Stockholm and Gothenburg. However, a comparison of the PFAS profile in Stockholm milk revealed distinct profiles for the time periods 1972-1996, 2000-2012, and 2013-2016, reflecting a shift in exposure over time. The lower bound estimated daily intake (EDI) for ∑PFAS concentrations in infants ranged from 7.1-40 ng per kg body weight per day (ng/kg bw/d) in Stockholm and from 5.2-25 ng/kg bw/d in Gothenburg over the studied time period, consistent with other European countries. Overall these data indicate that exposure to some legacy PFASs via breastmilk is declining, presumably as a result of regulation and phase-out initiatives. However, increasing concentrations for other PFASs and a shift in the overall PFAS profile in recent years may pose an ongoing health risk to infants.

Suitability of lemon balm (Melissa officinalis L.) extract rich in rosmarinic acid as a potential enhancer of functional properties in cupcakes

Melissa officinalis (lemon balm) and its extracts have been frequently reported as possessing bioactive properties, offering the potential for use in development/enrichment of food products with additional functional capabilities, providing health benefits to consumers. The antioxidant, antibacterial and antifungal activity of lemon balm extract, as well as its potential hepatotoxicity were thoroughly evaluated. The extracts were then incorporated into cupcakes and their preserving effect, chemical composition, colour parameters and antioxidant activity were compared with those provided by potassium sorbate. In general, the variables with the largest differences among different storage times were energy level, sucrose, glucose, palmitic acid (C6:0) and oleic acid (C18:1n9). On the other hand, L∗ (top), a∗ (top), b∗ (top), pH, capric acid (C10:0) and lauric acid (C12:0) showed the greatest variation according to cupcake formulation. The results observed indicate that the lemon balm extract rich in rosmarinic acid can provide advantageous functional properties to bakery products.

Co-metabolism of substrates by Bacillus thuringiensis regulates polyhydroxyalkanoate co-polymer composition

Polyhydroxyalkanoate (PHA) production by Bacillus thuringiensis EGU45 was studied by co-metabolism of crude glycerol (CG) (1%, v/v), glucose (0.05-0.5%, w/v) and propionic acid (0.05-0.5%, v/v) under batch (shake flask) culture conditions. Glycerol+PA combination resulted in 15-100mg/L PHA co-polymers with a HV content of 33-81mol%. The addition of NH₄Cl (0.5%, w/v) to CG+PA enhanced PHA production by 1.55-fold, with a HV content of 58-70mol%. The time period of incubation of PA to the feed: CG+glucose was optimized to be 3h after initiation of fermentation. The PHA contents were found to be stable at 1900-2050mg/L up scaling from 0.4 to 2.0L feed material. Biochemical characterization through GC-MS of PHA co-polymer revealed the presence of 3-hydroxydecanoate (3-HDD), 3-hydroxyoctadecanoate (3HOD), 3-hydroxyhexadecanoate (3HHD).

Chemotaxonomic perspectives of the Paracaryum (Cynoglosseae, Boraginaceae) taxa based on fruit fatty acid composition

Paracaryum is a medium sized genus in Cynoglosseae. This study represents the most comprehensive phytochemical investigation of Paracaryum to date. The fatty acid compositions of the fruits of ten Paracaryum taxa belonging to three different subgenera were investigated for chemotaxonomic allocation using gas chromatography. The fatty acid profiles of seven Paracaryum taxa, five of which are endemic to Turkey, were recorded for the first time. Among the twenty-two analysed fatty acids, oleic, linoleic and α-linolenic acids were the major fatty acids represented. The oleic acid content ranged from 22.1% in P. hirsutum to 51.7% in P. lithospermifolium subsp. cariense var. erectum; linolenic acid content ranged from 8.6% in P. lithospermifolium subsp. cariense var. erectum to 20.7% in P. erysimifolium; α-linolenic acid content ranged from 7.5% in P. lithospermifolium subsp. cariense var. erectum to 13.5% in P. cristatum subsp. cristatum; gamma linolenic acid content ranged from 2.8% in P. erysimifolium to 6.0% in P. hirsutum. Additional fatty acids also displayed varying levels in different species; palmitic acid content accounted for 17.7% in P. erysimifolium, erucic acid content was 8.73% in P. strictum, eicosenoic acid content was 6.0% in P. cristatum subsp. cristatum, eicosadienoic acid content was 4.4% in P. hirsutum, and stearic acid content was 4.3% in P. erysimifolium. The classification of the tribe Cynoglosseae remains controversial despite the many intensive morphological and phylogenetic investigations that have been carried out. Our fatty acid data from Paracaryum were analysed together with previously recorded fatty acid data from Cynoglosseae s.l. taxa to examine the chemotaxonomic contribution to the classification among taxa in Cynoglosseae by multivariate methods, including the unweighted pair group method with arithmetic mean and principal component analysis. An assessment of these chemometrics data supported the chemotaxonomic position of the genus Paracaryum in the tribe Cynoglosseae. While the principal component graphic did not depict clear separation of the three subgenera of Paracaryum, the principal component analysis revealed the chemotaxonomic significance of palmitic, linoleic, capric, and oleic acids.

Getting on with persistent pollutants: Decreasing trends of perfluoroalkyl acids (PFAAs) in sewage sludge

Sewage sludge can be a relevant source of perfluoroalkyl acids (PFAAs) for the environment. In order to reduce emissions from this source, Bavarian authorities enforced in 2008 an analysis of PFAAs from sewage sludge derived from municipal wastewater treatment plants (WWTPs). 4981 sludge samples from 1165 different WWTPs were analyzed between 2008 and 2013 for 11 PFAAs compounds. During this period, 71 WWTPs exceeded the precautionary limit of 125 μg kg(-1) dm of total PFAAs in sludge samples at least once with a decreasing tendency. The yearly exceedances of the investigated WWTPs decreased from 6% in 2008 to 0.8% in 2013. At the same time, the percentage of uncontaminated WWTPs increased from 33% to 65%. Perfluorooctane sulfonic acid (PFOS) was the predominant compound found in 41% of all sludge samples. Perfluorodecanoic acid (PFDA) was detected in 19% and Perfluorooctanoic acid (PFOA) in 7%. Very high PFAAs concentrations (>500 μg kg(-1) dm) in sewage sludge were generally caused by firefighting foams containing PFAAs or emissions from PFAAs-using industries including metal plating, textile, leather or paper industries. Trend analyses of the six year period show that PFAAs contamination in sewage sludge clearly decreased for 47% of the WWTPs. However, for 16% of the WWTPs an increasing trend was detected, even though the concentration levels were below the precautionary limit. During the six years of investigation the load of total PFAAs in sewage sludge was reduced by more than 90%, from 17 t a(-1) in 2008 to 1.5 t a(-1) in 2013.

Spatial distribution of perfluoroalkyl substances in surface sediments of five major rivers in China

Perfluoroalkyl substances (PFASs) have received great attention from the public and scientific community due to their potential adverse impacts on the ecosystem and human health. We investigated the occurrence and distribution of 16 PFASs from 2 classes of PFASs-perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids-in the archived surface sediments of five major rivers (Yellow River, Hai River, Liao River, Zhujiang River, and Dongjiang River) in northern and southern China. The study was also performed during the wet and dry seasons. Perfluorooctanoic acid and perfluorooctane sulfonic acid were the most frequently detected (detection frequency = 100 and 63 %, respectively) in the sediments of the five rivers; the concentrations ranged from 0.08 to 0.99 ng/g dry weight (dw) and were lower than the limit of detection (<LOD), which is 3.89 ng/g dw for both. Perfluorodecanoic acid and perfluoroundecanoic acid were moderately detected (detection frequency = 42 and 44 %, respectively) with concentrations ranging from less than their limit of detection (<LOD) to 0.69 ng/g dw and <LOD to 0.22 ng/g dw, whereas 12 other target analytes were lower than their limit of quantification at most of the sampling sites. Greater concentrations of the PFASs were found at those sites located in urban areas compared with rural areas. Sediment organic content was found to be an important factor influencing the distribution of PFASs in the riverine environment. The results provided first-hand national data of PFASs in the sediments of major rivers in China.

Perfluoroalkyl acids and their precursors in Swedish food: The relative importance of direct and indirect dietary exposure

We analyzed food market basket samples obtained in Sweden from 1999, 2005, and 2010 for perfluoroalkyl acids (PFAAs) and a range of precursor compounds. Perfluorooctane sulfonic acid (PFOS) precursors were detected in all food year pools with the highest concentrations in 1999. Six polyfluoroalkyl phosphate diesters (diPAPs, 4:2/6:2, 6:2/6:2, 6:2/8:2, 8:2/8:2, 6:2/10:2, and 10:2/10:2) were detected in the year pools with the highest ∑diPAP concentrations in 1999 and 2005. All precursors were predominantly found in meat, fish, and/or eggs based on analysis of individual food groups from 1999. Based on year pools, PFOS precursors contributed between 4 and 1% as an indirect source to total dietary PFOS intakes between 1999 and 2010. Perfluorohexanoic acid (PFHxA) exposure originated entirely from diPAPs, whereas for perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA), diPAPs contributed between 1 and 19% to total exposure. The lowest precursor contributions were generally seen in food samples from 2010.

Estimating human exposure to PFOS isomers and PFCA homologues: the relative importance of direct and indirect (precursor) exposure

Contributions of direct and indirect (via precursors) pathways of human exposure to perfluorooctane sulfonic acid (PFOS) isomers and perfluoroalkyl carboxylic acids (PFCAs) are estimated using a Scenario-Based Risk Assessment (SceBRA) modelling approach. Monitoring data published since 2008 (including samples from 2007) are used. The estimated daily exposures (resulting from both direct and precursor intake) for the general adult population are highest for PFOS and perfluorooctanoic acid (PFOA), followed by perfluorohexanoic acid (PFHxA) and perfluorodecanoic acid (PFDA), while lower daily exposures are estimated for perfluorobutanoic acid (PFBA) and perfluorododecanoic acid (PFDoDA). The precursor contributions to the individual perfluoroalkyl acid (PFAA) daily exposures are estimated to be 11-33% for PFOS, 0.1-2.5% for PFBA, 3.7-34% for PFHxA, 13-64% for PFOA, 5.2-66% for PFDA, and 0.7-25% for PFDoDA (ranges represent estimated precursor contributions in a low- and high-exposure scenario). For PFOS, direct intake via diet is the major exposure pathway regardless of exposure scenario. For PFCAs, the dominant exposure pathway is dependent on perfluoroalkyl chain length and exposure scenario. Modelled PFOS and PFOA concentrations in human serum using the estimated intakes from an intermediate-exposure scenario are in agreement with measured concentrations in different populations. The isomer pattern of PFOS resulting from total intakes (direct and via precursors) is estimated to be enriched with linear PFOS (84%) relative to technical PFOS (70% linear). This finding appears to be contradictory to the observed enrichment of branched PFOS isomers in recent human serum monitoring studies and suggests that either external exposure is not fully understood (e.g. there are unknown precursors, missing or poorly quantified exposure pathways) and/or that there is an incomplete understanding of the isomer-specific human pharmacokinetic processes of PFOS, its precursors and intermediates.

Perfluoroalkylated substances in the global tropical and subtropical surface oceans

In this study, perfluoroalkylated substances (PFASs) were analyzed in 92 surface seawater samples taken during the Malaspina 2010 expedition which covered all the tropical and subtropical Atlantic, Pacific and Indian oceans. Nine ionic PFASs including C6-C10 perfluoroalkyl carboxylic acids (PFCAs), C4 and C6-C8 perfluoroalkyl sulfonic acids (PFSAs) and two neutral precursors perfluoroalkyl sulfonamides (PFASAs), were identified and quantified. The Atlantic Ocean presented the broader range in concentrations of total PFASs (131-10900 pg/L, median 645 pg/L, n = 45) compared to the other oceanic basins, probably due to a better spatial coverage. Total concentrations in the Pacific ranged from 344 to 2500 pg/L (median = 527 pg/L, n = 27) and in the Indian Ocean from 176 to 1976 pg/L (median = 329, n = 18). Perfluorooctanesulfonic acid (PFOS) was the most abundant compound, accounting for 33% of the total PFASs globally, followed by perfluorodecanoic acid (PFDA, 22%) and perfluorohexanoic acid (PFHxA, 12%), being the rest of the individual congeners under 10% of total PFASs, even for perfluorooctane carboxylic acid (PFOA, 6%). PFASAs accounted for less than 1% of the total PFASs concentration. This study reports the ubiquitous occurrence of PFCAs, PFSAs, and PFASAs in the global ocean, being the first attempt, to our knowledge, to show a comprehensive assessment in surface water samples collected in a single oceanic expedition covering tropical and subtropical oceans. The potential factors affecting their distribution patterns were assessed including the distance to coastal regions, oceanic subtropical gyres, currents and biogeochemical processes. Field evidence of biogeochemical controls on the occurrence of PFASs was tentatively assessed considering environmental variables (solar radiation, temperature, chlorophyll a concentrations among others), and these showed significant correlations with some PFASs, but explaining small to moderate percentages of variability. This suggests that a number of physical and biogeochemical processes collectively drive the oceanic occurrence and fate of PFASs in a complex manner.

Sorption of Perfluorinated Compounds onto different types of sewage sludge and assessment of its importance during wastewater treatment

The distribution coefficient (Kd) and the organic carbon distribution coefficient (KOC) were determined for four Perfluorinated Compounds (PFCs) to three different types of sludge taken from a conventional Sewage Treatment Plant (STP). Batch experiments were performed in six different environmental relevant concentrations (200ngL(-1)to 5μgL(-1)) containing 1gL(-1) sludge. Kd values ranged from 330 to 6015, 329 to 17432 and 162 to 11770Lkg(-1) for primary, secondary and digested sludge, respectively. The effects of solution's pH, ionic strength and cation types on PFCs sorption were also evaluated. Sorption capacities of PFCs significantly decreased with increased pH values from 6 to 8. Furthermore, the divalent cation (Ca(2+)) enhanced PFCs sorption to a higher degree in comparison with the monovalent cation (Na(+)) at the same ionic strength. The obtained Kd values were applied to estimate the sorbed fractions of each PFC in different stages of a typical STP and to calculate their removal through treated wastewater and sludge. In primary settling tank, the predicted sorbed fractions ranged from 3% for Perfluorooctanoic Acid (PFOA) to 55% for Perfluoroundecanoic acid (PFUdA), while in activated sludge tank and anaerobic digester sorption was more than 50% for all target compounds. Almost 86% of initial PFOA load is expected to be detected in treated wastewater; while Perfluorodecanoic acid (PFDA), PFUdA and Perfluorooctanesulfonate (PFOS) can be significantly removed (>49%) via sorption to primary and excess secondary sludge. In anaerobic digester, the major part (>76%) of target PFCs is expected to be sorbed to sludge, while almost 3% of initial PFOA load will be detected in sludge leachates.

Perfluoroalkyl and polyfluoroalkyl substances in sediments from South Bohai coastal watersheds, China

This study investigated the concentrations and distribution of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) in sediments of 12 rivers from South Bohai coastal watersheds. The highest concentrations of ΣPFAS (31.920 ng g(-1) dw) and PFOA (29.021 ng g(-1) dw) were found in sediments from the Xiaoqing River, which was indicative of local point sources in this region. As for other rivers, concentrations of ΣPFAS ranged from 0.218 to 1.583 ng g(-1) dw were found in the coastal sediments and from 0.167 to 1.953 ng g(-1) dw in the riverine sediments. Predominant PFAS from coastal and riverine areas were PFOA and PFBS, with percentages of 30% and 35%, respectively. Partitioning analysis showed the concentrations of PFNA, PFDA and PFHxS were significantly correlated with organic carbon. The results of a preliminary environmental hazard assessment showed that PFOS posed the highest hazard in the Mi River, while PFOA posed a relative higher hazard in the Xiaoqing River.

Occurrence of perfluorinated compounds in raw water from New Jersey public drinking water systems

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were previously detected (≥ 4 ng/L) in 65% and 30%, respectively, of 23 New Jersey (NJ) public drinking water systems (PWS) sampled in 2006. We now report on a 2009 study of the occurrence of PFOA, PFOS, and eight other perfluorinated compounds (PFCs) in raw water samples from 30 intakes (18 groundwater and 12 surface water) from 29 additional NJ PWS. Between 1 and 8 PFCs were detected (≥ 5 ng/L) in 21 (70%) of 30 PWS samples at total PFC concentrations of 5-174 ng/L. Although PFOA was the most commonly detected PFC (57% of samples) and was found at the highest maximum concentration (100 ng/L), some of the higher levels of other PFCs were at sites with little or no PFOA. Perfluorononanoic acid was detected more frequently (30%) and at higher concentrations (up to 96 ng/L) than in raw or finished drinking water elsewhere, and it was found at several sites as the sole or predominant PFC, a pattern not reported in other drinking water studies. PFOS, perfluoropentanoic acid, and perfluorohexanoic acid were each detected in more than 20% of samples, while perfluoroheptanoic acid, perfluorobutane sulfonic acid, and perfluorohexane sulfonic acid were detected less frequently. Perfluorobutanoic acid was found only once (6 ng/L), and perfluorodecanoic acid was not detected. Total PFCs were highest in two reservoirs near an airfield; these were also the only sites with total perfluorosulfonic acids higher than total perfluorocarboxylic acids (PFCAs). PFC levels in raw and finished water from the same source were similar at those sites where both were tested. Five wells of two additional NJ PWS known to be contaminated with PFOA were also each sampled 4-9 times in 2010-13 for nine of the same PFCs. Total PFCs (almost completely PFCAs) at one of these PWS located near an industrial source of PFCs were higher than in any other PWS tested (up to 330 ng/L). These results show that multiple PFCs are commonly found in raw water from NJ PWS. Future work is needed to develop approaches for assessing the potential human health risks of exposure to mixtures of PFCs found in drinking water and other environmental media.

Levels and profiles of long-chain perfluorinated carboxylic acids in human breast milk and infant formulas in East Asia

In this study, 90 human breast milk samples collected from Japan, Korea, and China were analyzed for perfluorooctanoic acid (PFOA) (C8), perfluorononanoic acid (PFNA) (C9), perfluorodecanoic acid (PFDA) (C10), perfluoroundecanoic acid (PFUnDA) (C11), perfluorododecanoic acid (PFDoDA) (C12), and perfluorotridecanoic acid (PFTrDA) (C13). In addition, infant formulas (n = 9) obtained from retail stores in China and Japan were analyzed. PFOA was the predominant compound and was detected in more than 60% of samples in all three countries. The PFOA, PFNA, PFDA, and PFUnDA levels in Japan were significantly higher than those in Korea and China (p<0.05). The PFTrDA level was highest in Korea (p<0.05). The median PFOA concentrations were 89 pg mL(-1) (48% of total perfluorinated carboxylic acids (PFCAs) (C8-C13)) in Japan, 62 pg mL(-1) (54%) in Korea, and 51 pg mL(-1) (61%) in China. The remaining ∑PFCAs (C9-C13) were 95 pg mL(-1) in Japan, 52 pg mL(-1) in Korea, and 33 pg mL(-1) in China. Among the long-chain PFCAs, odd-numbered PFCAs were more frequently detected than even-numbered PFCAs, except for PFDA in Japan. There were no evident correlations between the mother's demographic factors and the PFCA concentrations. PFOA, PFNA, and PFDA were frequently detected in both Japan and China, but there were no significant differences between the two countries. The total PFCA concentrations in the infant formulas were lower than those in the breast milk samples in Japan (p<0.05), but not in China (p>0.05). In conclusion, various PFCAs were detected in human breast milk samples from East Asian countries.

Novel perspectives on the bioaccumulation of PFCs--the concentration dependency

The effects of exposure concentration on the bioaccumulation of four perfluorinated chemicals (PFCs): perfluorooctanesulfonate (PFOS), perfluoroocanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA), was investigated using green mussels, Perna viridis. Mussels were exposed to concentrations of 1 μgL(-1) and 10 μgL(-1) of each PFC for 56 days, and the bioaccumulation factors (BAF) were found to range from 15 to 859 L/kg and from 12 to 473 L/kg at 1 μgL(-1) and 10 μgL(-1), respectively. For all compounds, the BAF was larger at the lower dosage. Results suggest that the bioaccumulation of PFCs is concentration dependent. This concentration dependency can be explained by a nonlinear adsorption mechanism, which was further supported by the experimental results. The sensitivity of BAF to exposure concentration was found to be positively related to perfluorinated chain length and the binding affinity of the compounds. Bioaccumulation of long chain carboxylates and sulfonates are more easily affected by concentration changes. The validity of the conventional kinetic method was examined by comparing the results with the fundamental steady-state method: in addition to the above-mentioned batch test, mussels were also subject to 24-day exposure (1 μgL(-1) and 10 μgL(-1)) followed by 24-day depuration. Contradictions were found in the resulting kinetic BAF and model curving fittings. A new kinetic model based on adsorption mechanism was proposed, which potentially provide more accurate description of the bioaccumulation process of PFCs.

Occurrence of perfluorinated organic acids in the North and Baltic seas. Part 1: distribution in sea water

PURPOSE

Due to their high water solubilities and mobilities, persistent, polar perfluorinated compounds (PFCs) such as perfluorinated carboxylates and sulfonates are likely to end up in the oceans. In part 1 of this study, their distribution in North and Baltic Sea water is reported, being of special interest because these seas are surrounded by highly industrialized countries with high population densities.

METHODS

A combination of solid-phase extraction and liquid chromatography coupled with tandem mass spectrometry was used after optimisation to determine nine PFCs with chain lengths of C(4) to C(10) in water samples at ultra-trace levels.

RESULTS

The observed concentration distribution and gradients were explained by oceanographic mixing processes and currents. The big rivers were identified as major input sources. At the mouth of the river Elbe, concentrations of 9 ng/L were observed for perfluorooctanoate (PFOA), and 8 ng/L for perfluorooctylsulfonate (PFOS); all other PFC concentrations ranged from 0.6 to 1.7 ng/L. At coastal stations, concentrations decreased to 3.8 ng/L (PFOA) and 1.8 ng/L (PFOS), dropping to 0.13 and 0.09 ng/L, respectively, towards the open sea. Along the Dutch coast, high perfluorobutylsulfonate concentrations (3.9 ng/L) were observed as regional characteristics. In the Baltic Sea, fairly even PFC distributions with low gradients were observed. Again, PFOA and PFOS were the major compounds (up to 1.1 and 0.9 ng/L).

CONCLUSION

The results underline the necessity to include PFCs in marine monitoring programs. Water was found to be a good matrix for monitoring environmental levels, sources, and transport pathways of PFCs.

Concentrations, distribution, and persistence of perfluoroalkylates in sludge-applied soils near Decatur, Alabama, USA

Sludges generated at a wastewater treatment plant (WWTP) in Decatur, Alabama have been applied to agricultural fields for more than a decade. Waste-stream sources to this WWTP during this period included industries that work with fluorotelomer compounds, and sludges from this facility have been found to be elevated in perfluoroalkylates (PFAs). With this knowledge, the U.S. Environmental Protection Agency collected soil samples from sludge-applied fields as well as nearby "background" fields for PFA analysis. Samples from the sludge-applied fields had PFAs at much higher concentrations than in the background fields; generally the highest concentrations were perfluorodecanoic acid (≤ 990 ng/g), perfluorododecanoic acid (≤ 530 ng/g), perfluorooctanoic acid (≤ 320 ng/g), and perfluorooctane sulfonate (≤ 410 ng/g). Contrasts in PFA concentration between surface and deeper soil samples tended to be more pronounced in long-chain congeners than shorter chains, perhaps reflecting relatively lower environmental mobilities for longer chains. Several PFAs were correlated with secondary fluorotelomer alcohols (sec-FTOHs) suggesting that PFAs are being formed by degradation of sec-FTOHs. Calculated PFA disappearance half-lives for C6 through C11 alkylates ranged from about 1 to 3 years and increase with increasing chain-length, again perhaps reflecting lower mobility of the longer-chained compounds.

Perfluorinated compounds in urban river sediments from Guangzhou and Shanghai of China

Perfluorinated compounds (PFCs) have been determined in various matrices within China including water bodies, precipitations, biota and non-occupationally PFCs-exposed populations in recent years, yet little attention has been focused on the distributions of PFCs in urban river sediments from Chinese major metropolises such as Guangzhou and Shanghai so far. In this study, sediment samples of 0-2 cm were collected from 13 sites in the Zhujiang River across Guangzhou and nine sites in the Huangpu River across Shanghai. PFCs analysis on these sediments via high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) system was implemented targeting eight analytes involving perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA) and perfluorotetradecanoic acid (PFTA). According to the analytical results, total concentrations of PFCs ([summation operator]PFCs) in sediments from the Zhujiang River were between 0.09 and 3.6 ng/g dry weight (dw), with PFOS being the dominant PFC contaminant in the river ranged from below LOD to 3.1 ng/g dw; while [summation operator]PFCs in sediments from the Huangpu River were between 0.25 and 1.1 ng/g dw, with PFOA being the main PFC contaminant in the river determined in the levels of 0.20-0.64 ng/g dw. Additionally, an overall decreasing trend of PFCs contaminations with depth was observed in both of two 60 cm sediment cores from the Zhujiang River and the Huangpu River each.

Experimental evaluation of oil mists using a semivolatile aerosol dichotomous sampler

The sampling performance of the semivolatile aerosol dichotomous sampler (SADS) was tested and compared with existing vapor and particle sampling methods: filtration, electrostatic precipitation, and vapor adsorption. Seven different test fluids were used to generate test droplets, and their concentrations and composition in each phase were evaluated using gas chromatography. The amount of wall loss inside the SADS was also evaluated. Combined vapor and particle concentrations for each test aerosol were not statistically different from one another as a function of test method. However, the particle concentrations estimated using the SADS were statistically higher than those from the other methods. In experiments with hexadecane, the particle concentrations estimated using the SADS, an electrostatic precipitator, and a glass fiber filter were 2.50 mg/m3, 0.05 mg/m3, and 0.01 mg/m3, respectively. For commercial metalworking fluid (MWF) droplets, compounds having low molecular weight were more prevalent in the vapor phase than those compounds with high molecular weight. The compositions of the particle phase were similar to those of the original fluids. The wall losses of hexadecane and bis(2-ethylhexyl) sebacate (BEHS) were 0.25% and 26.5% of combined vapor and particle concentrations in the SADS sampling, respectively. Because it can avoid evaporative losses, SADS will sample semivolatile aerosols more accurately than common filtration methods and may often yield higher particle concentrations than can be measured using the other methods.

An LC method for monitoring medium-chain fatty acid permeation through CaCo-2 cell monolayers

A simple method was developed for monitoring the permeation of medium-chain fatty acids of C8 (octanoic acid) and C10 (decanoic acid) through CaCo-2 cell monolayers by high-performance liquid chromatography with electrochemical detection (HPLC-ECD). The detection was made based on the electrochemical reduction prepeak of quinone caused by acids, requiring the fabrication of a two-channel HPLC-ECD system. In one channel, acetonitrile-water (7:3, v/v) was used as a mobile phase to separate acids by a C30 column. In the other channel, acetonitrile-water (7:3, v/v) containing 6 mmol/L 3,5-di-t-butyl-1,2-benzoquinone and 20 mmol/L LiClO(4) was used as a quinone solution to detect acids by an electrochemical cell with a glassy carbon working electrode. In this HPLC-ECD system, eluted acids were mixed with the quinone solution in a post column fashion to obtain current signals caused by acids. The peak area was found to be linearly related to the acid amount ranging from 25 to 1,000 pmol (r > 0.992). The detection limits of octanoic acid and decanoic acid were 7.5 and 8.8 pmol, respectively. Octanoic acid and decanoic acid spiked into cell culture media samples were extracted with acetonitrile and their recoveries were more than 89.5% with an RSD of less than 8.2%. This method was applied to the permeation experiment of octanoic acid and decanoic acid with CaCo-2 cell monolayers formed on the Transwell system.

Aureobasidin, new antifouling metabolite from marine-derived fungus Aureobasidium sp

Two antifouling compounds, aureobasidin (1), a new ester with an unusual 4,6-dihydroxydecanoic acid residue, and (3R,5S)-3,5-dihydroxydecanoic acid (2), were isolated from the marine-derived fungus Aureobasidium sp., in addition to (5R,3Z)-5-hydroxydec-3-enoic acid (3) and (R)-3-hydroxydecanoic acid (4). The structures were unambiguously established by IR, 1D and 2D NMR spectroscopic and mass spectral data. Compounds 1-3 were found to be active against Bacillus subtilis, Escherichia coli and Staphyllococcus aureus. Compound 3 showed fungistatic activity against Candida albicans.

Perfluorooctane sulfonate (PFOS) and other fluorochemicals in fish blood collected near the outfall of wastewater treatment plant (WWTP) in Beijing

Perfluorinated compounds (PFCs) were measured in zooplankton and five fish species collected from Gaobeidian Lake, which receives discharge from wastewater treatment plant (WWTP) in Beijing, China. The mean total PFCs in five fish were in the order: crucian carp>common carp>leather catfish>white semiknife carp>tilapia. Perfluorooctane sulfonate (PFOS) occurred at the greatest concentrations, with mean concentrations ranging from 5.74 to 64.2 ng/ml serum. Perfluorodecanoic acid (PFDA) was the second dominant PFC in fish samples except for common carp in which perfluorooctane sulfonamide (PFOSA) was dominant. A positive linear relationship (r(2)=0.85, p<0.05) was observed between lnPFOS concentrations (ln ng/ml) and trophic level (based on delta15N) if tilapia was excluded. The risk assessment showed that PFOS might not pose an immediate risk to fish in Gaobeidian Lake.

Skipjack tuna as a bioindicator of contamination by perfluorinated compounds in the oceans

Perfluorinated chemicals (PFCs) have emerged as global environmental contaminants. Studies have reported the widespread occurrence of PFCs in biota from marine coastal waters and in remote polar regions. However, few studies have reported the distribution of PFCs in biota from offshore waters and open oceans. In this study, concentrations of nine PFCs were determined in the livers of 60 skipjack tuna (Katsuwonus pelamis) collected from offshore waters and the open ocean along the Pacific Rim, including the Sea of Japan, the East China Sea, the Indian Ocean, and the Western North Pacific Ocean, during 1997-1999. At least one of the nine PFCs was found in every tuna sample analyzed. Overall, perfluorooctanesulfonate (PFOS) and perfluoroundecanoic acid (PFUnDA) were the predominant compounds found in livers of tuna at concentrations of <1-58.9 and <1-31.6 ng/g, wet wt, respectively. Long-chain perfluorocarboxylates such as perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA) were common in the tuna livers. In livers of tuna from several offshore and open-ocean locations, concentrations of PFUnDA were greater than the concentrations of PFOS. The profiles and concentrations of PFCs in tuna livers suggest that the sources in East Asia are dominated by long-chain perfluorocarboxylates, especially PFUnDA. High concentrations of PFUnDA in tuna may indicate a shift in sources of PFCs in East Asia. The spatial distribution of PFOS in skipjack tuna reflected the concentrations previously reported in seawater samples from the Pacific and Indian Oceans, suggesting that tuna are good bioindicators of pollution by PFOS. Despite its predominance in ocean waters, PFOA was rarely found in tuna livers, indicative of the low bioaccumulation potential of this compound. Our study establishes baseline concentrations of PFCs in skipjack tuna from the oceans of the Asia-Pacific region, enabling future temporal trend studies of PFCs in oceans.

Perfluoroalkyl acids in the egg yolk of birds from Lake Shihwa, Korea

Concentrations of perfluoroalkyl acids (PFAs) were measured in egg yolks of three species of birds, the little egret (Egretta garzetta), little ringed plover (Charadrius dubius), and parrot bill (Paradoxornis webbiana), collected in and around Lake Shihwa, Korea, which receives wastewaters from an adjacent industrial complex. Mean concentrations of perfluorooctanesulfonate (PFOS) ranged from 185 to 314 ng/g ww and were similar to those reported for bird eggs from other urban areas. Long-chain perfluorocarboxylic acids (PFCAs) were also found in egg yolks often at great concentrations. Mean concentrations of perfluoroundecanoic acid (PFUnA) ranged from 95 to 201 ng/g ww. Perfluorooctanoic acid was detected in 32 of 44 egg samples, but concentrations were 100-fold less than those of PFOS. Relative concentrations of PFAs in all three species were similar with the predominance of PFOS (45-50%). There was a statistically significant correlation between PFUnA and perfluorodecanoic acid in egg yolks (p < 0.05), suggesting a common source of PFCAs. Using measured egg concentrations and diet concentrations, the ecological risk of the PFOS and PFA mixture to birds in Lake Shihwa was evaluated using two different approaches. Estimated hazard quotients were similar between the two approaches. The concentration of PFOS associated with 90th centile in bird eggs was 100-fold less than the lowest observable adverse effect level determined for birds, and those concentrations were 4-fold less than the suggested toxicity reference values. On the basis of limited toxicological data, current concentrations of PFOS are less than what would be expected to have an adverse effect on birds in the Lake Shihwa region.

Unique lipid a modifications in Pseudomonas aeruginosa isolated from the airways of patients with cystic fibrosis

Three structural features of lipid A (addition of palmitate [C16 fatty acid], addition of aminoarabinose [positively charged amino sugar residue], and retention of 3-hydroxydecanoate [3-OH C10 fatty acid]) were determined for Pseudomonas aeruginosa isolates from patients with cystic fibrosis (CF; n=86), from the environment (n=13), and from patients with other conditions (n=14). Among P. aeruginosa CF isolates, 100% had lipid A with palmitate, 24.6% with aminoarabinose, and 33.3% retained 3-hydroxydecanoate. None of the isolates from the environment or from patients with other conditions displayed these modifications. These results indicate that unique lipid A modifications occur in clinical P. aeruginosa CF isolates.

Fatty acid composition of Abies pindrow (West Himalayan fir)

The leaves of Abies pindrow, collected from Murree Hills, Punjab (Pakistan) revealed the presence of eleven fatty acids including eight saturated and three unsaturated fatty acids. They ranged from C(14) to C(24) and were detected as methyl esters by GC-MS technique. The saturated fatty acids were present in much greater proportion than unsaturated ones. Isopalmatic acid was found to be major saturated fatty acid and the oleic acid as predominant unsaturated acid. (+)-14-Methyl palmatic acid and (+)-Isosteric acid were the next higher saturated and unsaturated fatty acids respectively.

Virgin queen mandibular gland signals of Apis mellifera capensis change with age and affect honeybee worker responses

The mandibular gland secretions of Apis mellifera capensis virgin queens were analyzed by gas chromatography-mass spectroscopy. Changes in the patterns of the mandibular gland volatiles of A. m. capensis virgin queens were followed from emergence until 14-d old. Ontogenetic changes in the mandibular gland secretions were largely quantitative in nature, delineating the age categories (global R = 0.612, P = 0.001), except for 7- and 14-d-old queens, which cannot be separated on their mandibular gland profiles (P = 0.2). (E)-9-Oxodec-2-enoic acid (9ODA) contributes most and most consistently to the dissimilarity between groups as well as the similarity within groups. Worker reactions to introduced virgin queens of various ages were recorded. Workers showed a significant increase in hostile reactions as queens aged (r = 0.615, N = 20, P < 0.05). Consequently, worker reactions and relative 9ODA production exhibit a positive queen age-dependent response.

Characterization of the microbial community in indoor environments by chemical marker analysis: an update and critical evaluation

We published recently an integrated procedure for applying chemical marker analysis to characterize the microbiology of indoor environments comprising a scheme for extraction and analysis of markers of endotoxin, peptidoglycan/bacterial biomass, and fungal biomass. In the present paper, we report some significant improvements and also new possibilities of the described approach. We found that while 3-hydroxy fatty acids (3-OH FAs) of 10-14 carbon chain lengths are useful endotoxin markers, longer 3-OH FAs (i.e. with 16 carbon atoms and more) may rather serve as markers of Actinobacteria. We introduced 13C-labeled 3-hydroxytridecanoic acid, from labeled Pectinatus cerevisiiphilus, as an internal standard to improve quantification of the 3-OH FAs in the gas chromatography-mass spectrometry analysis. Finally, in experiments aiming to identify a suitable method for collection of house dust for chemical marker analysis, we found that the marker compositions of dusts sedimented on plexiglass plates that were spatially well-distributed in a studied room at different heights above floor level, were undistinguishable. This type of sampling thus appears to be well suited for use, e.g. in epidemiological studies. In summary, the presented work describes important new capabilities of chemical marker analysis in defining human exposure to microorganisms in indoor environments.

PRACTICAL IMPLICATIONS

We are developing an integrated methodology for characterizing the microbiology of indoor environments where specific microbial monomeric constituents in building materials and inhalable house dust particles are determined by using mass spectrometry-based methods. The methodology should represent a firm basis in research aiming to relate microbial exposure indoors to well-being and health.

[Search for yeast producers of brassylic and sebacic fatty acids]

Yeast cultures belonging to the genera Candida, Torulopsis, Saccharomyces, Debaryomyces, Hansenula, Pichia, and Yarrowia, capable of synthesizing brassylic and sebacic fatty acids, were screened. Overall, about 200 cultures grown in media containing decane or tridecane as a sole source of carbon were tested. On the medium with tridecane, yeasts synthesized insignificant amounts of brassylic acid. Sebacic acid was produced more intensively in the medium with n-decane. The culture Candida tropicalis, displaying the highest ability to synthesize sebacic acid, was selected.

Detection of Tinuvin 770, A Light Stabilizer of Plastic Materials from Dialysis Membranes, by High-Performance Liquid Chromatographic Analysis

Tinuvin 770 [bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate] is a pharmacologically active agent used worldwide as a light stabilizer for plastic materials. In vitro studies show that it is an L-type Ca(2+) channel and neuronal nicotic acethylcholine receptor blocker. Hypotension, vegetative dysfunction, and neurological symptoms are frequently observed during a haemodialysis treatment. The release of Tinuvin 770 from plastic materials applied in haemodialysis may play a part in the development of clinical signs. In our study, four different commonly used haemodialysis membranes (polysulphon, cuprophan, and two types of hemophan) are examined. The polymers are soaked for 72 h in physiological saline solution. Isolation is carried out using a Waters Oasis SPE column for solid-phase extraction and by high-performance liquid chromatography (HPLC) with electrospray ionization-mass spectrometric detection. Tinuvin 770 release is detected from all examined membranes. Validation studies show a satisfactory selectivity, linearity, accuracy, and recovery of this method. Our results suggest that Tinuvin 770 could have specific toxicological and therapeutic importance related to haemodialysis treatment. The developed HPLC method is suitable for the detection of Tinuvin 770.

Effect of dose of calcium salts of conjugated linoleic acid (CLA) on percentage and fatty acid content of milk fat in midlactation holstein cows

Increasing conjugated linoleic acid (CLA) content of milk fat from lactating dairy cattle has become a research interest due to the possible health benefits afforded humans consuming CLA. Dietary supplementation of CLA to lactating dairy cows is one potential method by which CLA content of milk and dairy products may be enhanced. Feeding CLA in calcium salt form could potentially deliver CLA to the lower digestive tract through prevention of biohydrogenation by rumen microbes. Milk fat depression (MFD) occurs when cows receive CLA-60, a commercially available CLA source containing numerous CLA isomers, abomasally. Our objectives were to determine the quantity of CLA as calcium salts required to elicit maximal MFD and to evaluate the effects of CLA supplementation on fatty acid composition of milk fat. Five Holstein cows at approximately 93 DIM were utilized in a 5 x 5 balanced Latin square crossover design. Periods were 14-d in length with a 5-d treatment phase and 9-d rest phase. Treatments were 5-d supplementation of 0, 12.5, 25, 50, and 100 g of CLA-60 in calcium salt form. Milk samples were collected on d 5 of CLA supplementation and analyzed for composition and fatty acid profile. Regression analysis of milk fat data suggested that MFD was not maximized over the dose levels investigated, despite delivery of 34.5 g of trans-10, cis-12 CLA in the 100-g dose of CLA. Supplementation with 50 and 100 g of CLA per day resulted in a reduction of milk fat percent of 29 and 34%, respectively. Trend analysis indicated a linear decrease in the milk fat content of caprylic, capric, and lauric acids as the dose of CLA increased. Milk fat content of cis-9, trans-11, and trans-10, cis-12 CLA increased at an increasing rate as dose increased.

Identification of phenyldecanoic acid as a constituent of triacylglycerols and wax ester produced by Rhodococcus opacus PD630

Phenyldecane supported growth and lipid accumulation of Rhodococcus opacus PD630 during cultivation under nitrogen-limiting conditions. The results of this study suggested that the hydrocarbon phenyldecane was degraded by monoterminal oxidation, followed by beta-oxidation of the alkyl side-chain to phenylacetic acid, and by an additional degradative route for the oxidation of the latter to intermediates of the central metabolism. alpha-Oxidation of phenyldecanoic acid also occurred to some extent. Phenyldecanoic acid, the monoterminal oxidation product, was also utilized for the biosynthesis of a novel wax ester and novel triacylglycerols. The formation of the wax ester phenyldecylphenyldecanoate probably resulted from the condensation of phenyldecanoic acid and phenyldecanol, which were produced as metabolites during the catabolism of phenyldecane. Two types of triacylglycerol were detected in phenyldecane-grown cells of strain PD630. Triacylglycerols containing only odd- and even-numbered aliphatic fatty acids, as well as triacylglycerols in which one fatty acid was replaced by a phenyldecanoic acid residue, occurred. Other phenyl intermediates, such as phenylacetic acid, phenylpropionic acid, 4-hydroxyphenylpropionic acid, protocatechuate and homogentisic acid, were excreted into the medium during cultivation on phenyldecane. On the basis of the results obtained, pathways for the catabolism and assimilation of phenyldecane by R. opacus PD630 are discussed.

Indirect fluorescence of aliphatic carboxylic acids in nonaqueous capillary electrophoresis using merocyanine 540

A method for the analysis of aliphatic carboxylic acids (ACAs) in nonaqueous capillary electrophoresis (NACE) in conjunction with indirect laser-induced fluorescence (ILIF) using merocyanine 540 (MC 540) is described. Performing the analysis in organic solvent is advantageous when using MC 540, because of its greater quantum yield in aprotic solvent. To achieve a high dynamic reserve (DR) and optimize resolution, we have tested a number of aqueous mixtures containing alcohols and acetonitrile (ACN). The optimum buffer for the analysis of C2-C18 ACAs, in terms of sensitivity, resolution, and speed, is an aqueous mixture of 40% ACN, 30% ethanol, and 1 mM Tris at apparent pH 7.4 (adjusted with ascorbic acid). Under this condition, the DR is greater than 1000, thereby the limits of detection for acids are in the range of sub-microM to microM. Linear plots show that the dynamic ranges for the analysis of ACAs are at least two decades in concentration, with regression coefficients all greater than 0.98. The relative standard deviations of the migration times and peak heights for all ACAs are less than 2.0%. Furthermore, this simple and cost-effective method has been applied to the analysis of marine lipid concentrate, with the concentrations of 1.67+/-0.03 and 4.50+/-0.05 mM (n = 5) for C14 and C16 acids, respectively, in a tablet of marine lipid concentrate sample.

Role of Yersinia intermedia and Pseudomonas putida in the development of a fruity off-flavour in pasteurized milk

Analysis by gas chromatography-mass spectrometry of pasteurized milk with a fruity (pineapple like) off odour and a sour, rancid and soapy taste indicated the presence of concentrations at microg/ml levels of ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, octanoic acid, decanoic acid and dodecanoic acid. The off-odour and taste were attributed to the presence of these compounds in the milk. Microbiological examination confirmed that the milk was also contaminated with a series of psychrotrophic bacteria including Yersinia intermedia, Pseudomonas putida and Rahnella aquatilis. Growth of isolates of these bacteria in UHT milk at 23 degrees C for 7 d showed that Yer. intermedia produced significant quantities of the C4-C12 alkanoic acids; Ps. putida produced only small quantities of these acids and Rah. aquatilis produced none. In addition, Yer. intermedia and Ps. putida also produced small but significant quantities of the corresponding ethyl esters. In milk inoculated with both Yer. intermedia and Ps. patida, the quantity of ethyl esters produced was greater than that found in cultures containing only one of the isolates. These studies indicated that Yer. intermedia was the principal source of the alkanoic acids in the tainted milk and that the major producer of the corresponding ethyl esters was Ps. patida. This is the first report that Yer. intermedia and Ps. putida can cause an off-odour or taste in dairy products.

Production of polyhydroxyalkanoic acids by Ralstonia eutropha and Pseudomonas oleovorans from an oil remaining from biotechnological rhamnose production

Screening experiments identified several bacteria which were able to use residual oil from biotechnological rhamnose production as a carbon source for growth. Ralstonia eutropha H16 and Pseudomonas oleovorans were able to use this waste material as the sole carbon source for growth and for the accumulation of polyhydroxyalkanoic acids (PHA). R. eutropha and P. oleovorans accumulated PHA amounting to 41.3% and 38.9%, respectively, of the cell dry mass, when these strains were cultivated in mineral salt medium with the oil from the rhamnose production as the sole carbon source. The accumulated PHA isolated from R. eutropha consisted of only 3-hydroxybutyric acid, whereas the PHA isolated from P. oleovorans consisted of 3-hydroxyhexanoic acid, 3-hydroxyoctanoic acid, 3-hydroxydecanoic acid, and 3-hydroxydodecanoic acid. The composition was confirmed by gas chromatography of the isolated polyesters. Batch and fed-batch cultivations in stirred-tank reactors were done.

A new HPLC method for the direct analysis of triglycerides of dicarboxylic acids in biological samples

Dicarboxylic acids (DA) are alternate lipid substrates recently proposed in parenteral nutrition. Two new derivatives of DA, a triglyceride of sebacic (TGC10) and one of dodecanedioic (TGC12) acid have been synthesised in order to reduce the amount of sodium given with the unesterified forms. The present paper describes a rapid and direct high-performance liquid chromatographic method (HPLC) for the analysis of these substances in both plasma and urine. Thirty-six male Wistar rats were rapidly injected with 64 mg of TGC10 or 53 mg of TGC12. The triglycerides and their products of hydrolysis were measured in plasma samples taken at different times. For the dose of 500 ng the intra-assay variations ranged from 6. 80+/-0.35% for TGC10 to 18.6+/-3.20% for TGC12 and the inter-assay variations were from 4.44+/-2.21% for TGC10 to 15.0+/-6.72% for TGC12. The detection limit for both triglycerides was 5 ng. This rapid and direct HPLC method could have practical implications in monitoring the concentration of both triglycerides and free forms of DA in biological samples of patients who might benefit from the administration of these substances during parenteral nutrition regimens.

Liquid chromatography/mass spectrometry analysis of mixtures of rhamnolipids produced by Pseudomonas aeruginosa strain 57RP grown on mannitol or naphthalene

Liquid chromatography/mass spectrometry using electrospray ionisation was used to analyse rhamnolipids produced by a Pseudomonas aeruginosa strain with mannitol or naphthalene as carbon source. Identification and quantification of 28 different rhamnolipid congeners was accomplished using a reverse-phase C(18) column and a 30 min chromatographic run. Isomeric rhamnolipids that were not chromatographically resolved could be identified by interpretation of their mass spectra and their relative proportions estimated. The most abundant rhamnolipid produced on mannitol contained two rhamnoses and two 3-hydroxydecanoic acid groups. The most abundant rhamnolipid produced from naphthalene contained two rhamnoses and one 3-hydroxydecanoic acid group.

Saccharomyces cerevisiae cell fatty acid composition and release during fermentation without aeration and in absence of exogenous lipids

Medium-chain fatty-acids (MCFA) are among the main aroma compounds of fermented beverages. High concentrations of MCFA have been found in sluggish and stuck fermentations. It has been suggested that they arrest cell growth, as they may be toxic, but the causes of sluggish and stuck fermentations are still unclear. The aim of this work was to see whether the production of MCFA is related to fatty acid synthesis in the absence of exogenous lipids and aeration, and whether their increase can be regarded as a consequence, instead of the cause, of sluggish and stuck fermentations. Two possibilities were considered: (i) MCFA are produced to replace unsaturated fatty acids (UFA) for cell membrane fluidity when the lack of oxygen makes desaturation of saturated fatty acids (SFA) impossible; or (ii) MCFA are produced following the release of medium-chain acyl-CoA from the fatty acid synthetase complex (FAS) due to the accumulation of SFA, and their hydrolysis to recycle CoA-SH. In the first hypothesis, MCFA should be active in cell metabolism and be found in cell structures; in the second, MCFA should be a discard and prevalently found outside the cell. We carried out a Saccharomyces cerevisiae fermentation experiment in a synthetic, lipid-free medium without aeration. We measured the fatty acid composition of yeast cells and the amounts of MCFA and their ethyl esters in the medium throughout the fermentation. Cell growth and the oxygen content of the medium were also monitored. We found that MCFA are not immobilized in cell structures, but mainly released into the medium. Cell growth is arrested because fatty acid biosynthesis is prevented by the lack of oxygen. The higher MCFA concentrations found in sluggish and stuck fermentations can be thus regarded as an effect, and not the cause, of this arrest. Some suggestions for the prevention of these events are proposed.

Determination of perfluorocarboxylic acids by gas-liquid chromatography in rat tissues

A method for the determination of tissue perfluorocarboxylic acids (PFCA) was developed using gas-liquid chromatography with an electron capture detector (ECD). Perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were efficiently extracted from rat liver, methylated with diazomethane, and separated on GLC. Internal standards that were added to liver homogenates were used in the quantitative analysis of PFCAs to correct the loss during the extraction and derivatization. The concentration of PFDA in rat liver 24 h after intraperitoneal administration at a dose of 20 mg/kg body weight was 113.9 +/- 11.4 microg/g liver. The value corresponds to the previously reported results that were obtained using [14C]PFDA.