Quantitative determination of perfluorochemicals and fluorotelomer alcohols in plants from biosolid-amended fields using LC/MS/MS and GC/MS.

Analytical methods for determining perfluorochemicals (PFCs) and fluorotelomer alcohols (FTOHs) in plants using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and gas chromatography/mass spectrometry (GC/MS) were developed, and applied to quantify a suite of analytes in plants from biosolid-amended fields. Dichloromethane-methanol and ethylacetate were chosen as extracting solutions for PFCs and FTOHs, respectively. Nine perfluorocarboxylic acids (PFCAs), three perfluorosulfonic acids (PFSAs), and ten FTOHs were monitored. Most PFCAs and perfluorooctanesulfonate (PFOS) were quantifiable in plants grown in contaminated soils, whereas PFCs went undetected in plants from two background fields. Perfluorooctanoic acid (PFOA) was a major homologue (∼10-200 ng/g dry wt), followed by perfluorodecanoic acid (∼3-170 ng/g). [PFOS] in plants (1-20 ng/g) generally was less than or equal to most [PFCAs]. The site-specific grass/soil accumulation factor (GSAF = [PFC](Grass)/[PFC](Soil)) was calculated to assess transfer potentials from soils. Perfluorohexanoic acid had the highest GSAF (= 3.8), but the GSAF decreased considerably with increasing PFCA chain length. Log-transformed GSAF was significantly correlated with the PFCA carbon-length (p < 0.05). Of the measured alcohols, 8:2nFTOH was the dominant species (≤1.5 ng/g), but generally was present at ≥10× lower concentrations than PFOA.

Concentrations, distribution, and persistence of fluorotelomer alcohols in sludge-applied soils near Decatur, Alabama, USA.

Soil samples were collected for fluorotelomer alcohol (FTOH) analyses from six fields to which sludge had been applied and one "background" field that had not received sludge. Ten analytes in soil extracts were quantified using GC/MS. Sludge-applied fields had surface soil FTOH concentrations exceeding levels found in the background field. For 8:2nFTOH, which can degrade to perfluorooctanoic acid, impacted surface-soils ranged from 5 to 73 ng/g dry weight, clearly exceeding the background field in which 8:2nFTOH was not detected. The highest [FTOH] generally was 10:2nFTOH, which had concentrations of <5.6 to 166 ng/g. For the first time, we document the persistence of straight-chained primary FTOHs (n-FTOHs) and branch-chained secondary FTOHs (sec-FTOHs), which are transformation products of n-FTOHs, in field soils for at least five years after sludge application. Ratios of sec-FTOHs to n-FTOHs were highest for 7:2sFTOH/8:2nFTOH (∼50%) and decreased with increasing chain length to a minimum for the longest-chained analytes, 13:2sFTOH/14:2nFTOH (∼10%). Disappearance half-lives for FTOHs, calculated with these data, ranged from 0.85 to 1.8 years. These analytical results show that the practice of sludge application to land is a pathway for the introduction of FTOHs and, accordingly, their transformation products, perfluorocarboxylic acids, into the environment.

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.

Analysis of fluorotelomer alcohols in soils: optimization of extraction and chromatography.

This article describes the development of an analytical method for the determination of fluorotelomer alcohols (FTOHs) in soil. The sensitive and selective determination of the telomer alcohols was performed by extraction with methyl tert-butyl ether (MTBE) and analysis of the extract using gas chromatography with detection and quantification by mass spectrometry operated in the positive chemical ionization mode. The protonated molecular ion, [M+H](+) and a fragment ion (loss of HF+H(2)O) m/z 38 less than the molecular ion were monitored to identify tentatively FTOHs in MTBE extracts of contaminated soils. The FTOHs were confirmed by treatment of the extract with a silylation reagent and observing the disappearance of the FTOH response and the appearance of peaks attributable to the [M+H](+) ions of the trimethylsilyl derivatives. Mass-labeled FTOHs were used as recovery and matrix internal standards. Recovery experiments on soils shown to be free of endogenous FTOHs at instrument detection limits (IDL) of 16 fg/microL for 6:2 FTOH, 10 fg/microL for 8:2 FTOH and 14 fg/microL for 10:2 FTOH yielded a limit of quantitation (LOQ) of 190, 100, and 160 fg/microL for 6:2 FTOH, 8:2 FTOH, and 10:2 FTOH, respectively when 3 g samples of soil were extracted with 1 mL MTBE. The levels of the 6:2 FTOH, 8:2 FTOH, and 10:2 FTOH in five soils contaminated with FTOHs by exposure to the laboratory atmosphere during air drying were determined. In these air-dried soils, concentrations of FTOHs ranged from non-detectable to 3600 fg/microL (0.6 ng/g) of the 6:2 FTOH in the extract of a commercial topsoil. This method was used to determine even and odd numbered FTOHs from 6:2 through 14:2 in soils from fields that had received applications of sewage sludge. Concentrations of FTOHs in these sludge-applied soils ranged as high as 820 ng/g of dry soil for the 10:2 FTOH.

Occurrence and mammalian cell toxicity of iodinated disinfection byproducts in drinking water.

An occurrence study was conducted to measure five iodo-acids (iodoacetic acid, bromoiodoacetic acid, (Z)-3-bromo-3-iodo-propenoic acid, (E)-3-bromo-3-iodo-propenoic acid, and (E)-2-iodo-3-methylbutenedioic acid) and two iodo-trihalomethanes (iodo-THMs), (dichloroiodomethane and bromochloroiodomethane) in chloraminated and chlorinated drinking waters from 23 cities in the United States and Canada. Since iodoacetic acid was previouslyfound to be genotoxic in mammalian cells, the iodo-acids and iodo-THMs were analyzed for toxicity. A gas chromatography (GC)/negative chemical ionization-mass spectrometry (MS) method was developed to measure the iodo-acids; iodo-THMs were measured using GC/high resolution electron ionization-MS with isotope dilution. The iodo-acids and iodo-THMs were found in waters from most plants, at maximum levels of 1.7 microg/L (iodoacetic acid), 1.4 microg/L (bromoiodoacetic acid), 0.50 microg/L ((Z)-3-bromo-3-iodopropenoic acid), 0.28 microg/L ((E)-3-bromo-3-iodopropenoic acid), 0.58 microg/L ((E)-2-iodo-3-methylbutenedioic acid), 10.2 microg/L (bromochloroiodomethane), and 7.9 microg/L (dichloroiodomethane). Iodo-acids and iodo-THMs were highest at plants with short free chlorine contact times (< 1 min), and were lowest at a chlorine-only plant or at plants with long free chlorine contact times (> 45 min). Iodide levels in source waters ranged from 0.4 to 104.2 microg/L (when detected), but there was not a consistent correlation between bromide and iodide. The rank order for mammalian cell chronic cytotoxicity of the compounds measured in this study, plus other iodinated compounds, was iodoacetic acid > (E)-3-bromo-2-iodopropenoic acid > iodoform > (E)-3-bromo-3-iodo-propenoic acid > (Z)-3-bromo-3-iodo-propenoic acid > diiodoacetic acid > bromoiodoacetic acid > (E)-2-iodo-3-methylbutenedioic acid > bromodiiodomethane > dibromoiodomethane > bromochloroiodomethane approximately chlorodiiodomethane > dichloroiodomethane. With the exception of iodoform, the iodo-THMs were much less cytotoxic than the iodo-acids. Of the 13 compounds analyzed, 7 were genotoxic; their rank order was iodoacetic acid >> diiodoacetic acid > chlorodiiodomethane > bromoiodoacetic acid > E-2-iodo-3-methylbutenedioic acid > (E)-3-bromo-3-iodo-propenoic acid > (E)-3-bromo-2-iodopropenoic acid. In general, compounds that contain an iodo-group have enhanced mammalian cell cytotoxicity and genotoxicity as compared to their brominated and chlorinated analogues.

Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we detected in all three of our test soils, endogenous concentrations of all of our PFCA analytes, C(6) through C(10)-the lowest concentrations being roughly 30 pg/g of dry soil for perfluorinated hexanoic and decanoic acids in an agricultural soil.

Analysis of perfluorinated carboxylic acids in soils: detection and quantitation issues at low concentrations.

Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can be quantitated using the method of standard additions, PFOA also can be quantitated less laboriously using 13C4-PFOA as a matrix internal standard. The impact of extract matrices on signal varied between soils and temporally during analytical runs rendering 13C4-PFOA unsuitable as a matrix internal standard for quantitating perfluorinated carboxylic acids (PFCAs) other than PFOA, which co-elutes with 13C4-PFOA. In fact, for soil extracts, quantitation of PFCAs based on external calibrations proved about as accurate as use of matrix internal standards for target analytes that do not co-elute with the matrix internal standard. Also, 13C4-PFOA should be used carefully as a matrix internal standard for trace levels of PFOA because some 13C4-PFOA standards contain trace impurities of unlabelled PFOA. When the presence of PFCAs in soil extracts is being determined by LC/MS/MS, detection limits are best defined by statistical methods that quantify the significance of contrast between analytical signal and background noise using multiple analyses. Further, when developing a calibration of low concentrations using weighted regression, the central tendency of the calibration line is best fitted using graphical depictions of error. As the MDL for the transition-product quantitation ion is approached in LC/MS/MS, relatively weak signals of transition-product confirmation ions can be used as a rejection criterion by looking for anomalously high values of the ratio of the confirmation to the quantitation ion.

A simple and fast extraction method for organochlorine pesticides and polychlorinated biphenyls in small volumes of avian serum.

A solid-phase extraction (SPE) method was developed using 8M urea to desorb and extract organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) from avian serum for analysis by capillary gas chromatography with electron capture detection (GC-ECD). The analytes were efficiently extracted from the denatured serum-lipoprotein-analyte complex by one passage through an Oasis((R)) hydrophilic-lipophilic-balanced (HLB) SPE cartridge. No further clean-up was necessary, the entire extraction procedure and GC-ECD analysis can be accomplished in less than 3h. Serum volumes ranged from 100 microL to 1 mL with absolute recoveries of 90-101% for PCBs and 74% to 101% for the OC pesticides.

Accumulation of perchlorate in tobacco plants: development of a plant kinetic model.

Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in plant tissues. This research determined the uptake, translocation, and accumulation of perchlorate in tobacco plants. Three hydroponics growth studies were completed under greenhouse conditions. Depletion of perchlorate in the hydroponics nutrient solution and accumulation of perchlorate in plant tissues were determined at two-day intervals using ion chromatography. Perchlorate primarily accumulated in tobacco leaves, yielding a substantial storage capacity for perchlorate. Mass balance results show that perchlorate degradation was negligible in plants. Tobacco plants were shown to effectively accumulate perchlorate over a wide range of initial concentrations (10 ppb to 100 ppm) from the hydroponics solution. Results suggest that plants are potential plants for the phytoremediation of perchlorate. A mathematical model was developed to describe the distribution of perchlorate in tobacco plants under rapid growth conditions. The Plant Kinetic (PK) model defined a plant as a set of compartments, described by mass balance differential equations and plant-specific physiological parameters. Data obtained from a separate hydroponics growth study with multiple solution perchlorate concentrations were used to validate predicted root, stem, and leaf concentrations. There was good agreement between model predictions and measured concentrations in the plant. The model, once adequately validated, can be applied to other terrestrial plants and inorganic chemicals currently used for both phytoremediation and ecological risk assessment.