A new analytical method was developed to quantify 26 newly-identified and 21 legacy (e.g. perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and fluorotelomer sulfonates) per and polyfluorinated ...alkyl substances (PFAS) in groundwater and aqueous film forming foam (AFFF) formulations. Prior to analysis, AFFF formulations were diluted into methanol and PFAS in groundwater were micro liquid-liquid extracted. Methanolic dilutions of AFFF formulations and groundwater extracts were analyzed by large-volume injection (900 μL) high-performance liquid chromatography tandem mass spectrometry. Orthogonal chromatography was performed using cation exchange (silica) and anion exchange (propylamine) guard columns connected in series to a reverse-phase (C18) analytical column. Method detection limits for PFAS in groundwater ranged from 0.71 ng/L to 67 ng/L, and whole-method accuracy ranged from 96% to 106% for analytes for which matched authentic analytical standards were available. For analytes without authentic analytical standards, whole-method accuracy ranged from 78 % to 144 %, and whole-method precision was less than 15 % relative standard deviation for all analytes. A demonstration of the method on groundwater samples from five military bases revealed eight of the 26 newly-identified PFAS present at concentrations up to 6900 ng/L. The newly-identified PFAS represent a minor fraction of the fluorinated chemicals in groundwater relative to legacy PFAS. The profiles of PFAS in groundwater differ from those found in fluorotelomer- and electrofluorination-based AFFF formulations, which potentially indicates environmental transformation of PFAS.
Eight samples were obtained to characterize the chemical loads in water recycled for reuse applications. The sources included stormwater, rooftop runoff, wastewater, mixed water, and drinking water ...as a comparison. The water was reused for irrigation, cleaning, toilet flushing, and cooling purposes. Large-volume injection (650 μL) high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry were employed to separate and detect features by suspect and non-target screening. The instrumental method had the advantage that no sample extractions were required prior to analysis. Two chromatographic methods were developed to separate positive- and negative-ionizing compounds and retention time models were developed for both. Retention time models provide an additional measure of confidence for probable and tentative identifications. The two models had predictive R2—which indicates how well the models predicts new observations—of 0.87. After data-reduction, the number of features detected in the samples ranged from 304 to 1513. Feature metrics such as the average response-per-feature provided a simple method to characterize similarities and differences between samples. Additionally, a statistical comparison was performed by principal component analysis. Of the 97 suspect-screening compounds, 20 were positively identified. Benzotriazole/benzothiazole-derivatives and per- and poly-fluoroalkyl substances were the most frequently detectedcompounds during suspect screening. Other compounds detected included pharmaceuticals, drug metabolites, and sucralose. Features were prioritized for non-target analysis based on in-house library matches, magnitude of response, and frequency of occurrence. Fifty-five unique compounds were positively identified via non-target analysis. The identified compounds included 17 pharmaceuticals, 17 pesticides, 13 industrial compounds, four personal-use compounds, and four biological compounds.
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•Large-volume injection eliminated the need for sample pre-concentration.•Retention models were developed to support non-target identifications.•Feature metrics and principal component analysis were used to compare samples.•Eighty-two individual contaminants were identified with level 1 or 2 confidence.•Several previously unreported environmental contaminants were identified.
Air and precipitation samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC–MS) for pharmaceuticals, personal care products, ...and other commercial chemicals within the St. Paul/Minneapolis metropolitan area of Minnesota, U.S. Of the 126 chemicals analyzed, 17 were detected at least once. Bisphenol A, N,N-diethyl-meta-toluamide (DEET), and cocaine were the most frequently detected; their maximum concentrations in snow were 3.80, 9.49, and 0.171ng/L and in air were 0.137, 0.370, and 0.033ng/m3, respectively. DEET and cocaine were present in samples of rain up to 14.5 and 0.806ng/L, respectively. Four antibiotics - ofloxacin, ciprofloxacin, enrofloxacin, and sulfamethoxazole - were detected at concentrations up to 10.3ng/L in precipitation, while ofloxacin was the sole antibiotic detected in air at 0.013ng/m3. The X-ray contrast agent iopamidol and the non-steroidal anti-inflammatory drug naproxen were detected in snow up to 228ng/L and 3.74ng/L, respectively, while caffeine was detected only in air at 0.069 and 0.111ng/m3. Benzothiazole was present in rain up to 70ng/L, while derivatives of benzotriazole – 4-methylbenzotriazole, 5-methylbenzotriazole, and 5-chlorobenzotriazole - were detected at concentrations up to 1.5ng/L in rain and 3.4ng/L in snow. Nonylphenol and nonylphenol monoethoxylate were detected once in air at 0.165 and 0.032ng/m3, respectively. Although the sources of these chemicals to atmosphere are not known, fugacity analysis suggests that wastewater may be a source of nonylphenol, nonylphenol monoethoxylate, DEET, and caffeine to atmosphere. The land-spreading of biosolids is known to generate PM10 that could also account for the presence of these contaminants in air. Micro-pollutant detections in air and precipitation are similar to the profile of contaminants reported previously for surface water. This proof of concept study suggests that atmospheric transport of these chemicals may partially explain the ubiquity of these contaminants in the aquatic environment.
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•Air and precipitation were analyzed for 126 pharmaceuticals and other chemicals.•Several pharmaceuticals, alkylphenols, anticorrosives, and cocaine were detected.•Wastewater may be a source of nonylphenol, DEET, and caffeine to the atmosphere.
An analytical method is presented here that is sensitive to the parts-per-quadrillion (pg/L) for estrogens in surface water. The estrogens included for study were estrone, 17β-estradiol, estriol, ...17α-ethinylestradiol, and equilin. The method consisted of the small-scale liquid–liquid extraction of surface water followed by derivation with dansyl chloride. Analyte separation and detection were performed by high-pressure liquid-chromatography and tandem mass-spectrometry. A large volume (100 μL) of the sample was injected on-column to increase the analyte mass sent to the detector. The detection limits of the method were 0.045 ng/L for estrone, 0.086 ng/L for 17β-estradiol, 0.030 ng/L for estriol, 0.049 ng/L for 17α-ethinylestradiol, and 0.13 ng/L for equilin. The whole-method accuracy ranged from 93 ± 5.8% to 105 ± 4.5% for all the analytes at two different spike levels. Similarly, the precision of the method was less than 8.0% relative standard deviation. The final method was used to analyze a series of samples from the Mississippi River spanning 51 river miles. Estrone was detected in all of the samples and 17β-estradiol was detected in one. Concentrations of estrone ranged from between the detection and quantification limits up to 0.63 ng/L. Increases in the concentration of estrone could be observed downstream from potential sources including a drinking water treatment plant. 17β-estradiol was detected below its quantitation limit in a sample taken downstream from a wastewater treatment plant.
•A novel method to quantify acrylamide in surface and drinking waters was developed.•The authors demonstrate the first application of LVI–HILIC.•The finalized method had detection and reporting ...limits below 20ng/L.•Acrylamide was detected in water samples from a sand-and-gravel mine.•The fate of acrylamide during drinking water treatment was assessed.
A simple and sensitive analytical method was developed to quantify levels of acrylamide in environmental and drinking waters. The analytical method consisted of solvent exchanging acrylamide from 2mL of water into 2mL of dichloromethane using acetonitrile as an intermediate. The sample was then directly analyzed by large-volume (750μL) injection – hydrophilic-interaction liquid chromatography and tandem mass spectrometry. The method detection limit and reporting level were 2.4ng/L and 17ng/L of acrylamide, respectively. The recovery of acrylamide during solvent exchange was 95±2.8% and the matrix effects were 12±2.2% in river water. The use of atmospheric-pressure chemical ionization reduced matrix effects; however, it also reduced method sensitivity by a factor of 2.2 compared to electrospray ionization. Matrix effects were compensated for by the use of an isotopically-labeled internal standard and the method accuracy was 89±3.0% at 25ng/L of acrylamide and 102±2.6% at 250ng/L of acrylamide. The precision of the method was less than 6% relative standard deviation at both 25ng/L and 250ng/L of acrylamide. Samples from a sand-and-gravel mine and a drinking-water treatment plant were acquired to demonstrate the method. The concentrations of acrylamide at the sand-and-gravel mine were up to 280ng/L. In the drinking-water treatment plant, the concentration of acrylamide was approximately double in the finished drinking water when compared to other stages in the drinking-water treatment process. Disinfection or fluoridation may result in higher concentrations of acrylamide in finished drinking water; however, further research in this area is necessary.
Poly- and perfluoroalkyl substances (PFASs) are a class of fluorinated chemicals that are utilized in firefighting and have been reported in groundwater and soil at several firefighter training ...areas. In this study, soil and groundwater samples were collected from across a former firefighter training area to examine the extent to which remedial activities have altered the composition and spatial distribution of PFASs in the subsurface. Log K oc values for perfluoroalkyl acids (PFAAs), estimated from analysis of paired samples of groundwater and aquifer solids, indicated that solid/water partitioning was not entirely consistent with predictions based on laboratory studies. Differential PFAA transport was not strongly evident in the subsurface, likely due to remediation-induced conditions. When compared to the surface soil spatial distributions, the relative concentrations of perfluorooctanesulfonate (PFOS) and PFAA precursors in groundwater strongly suggest that remedial activities altered the subsurface PFAS distribution, presumably through significant pumping of groundwater and transformation of precursors to PFAAs. Additional evidence for transformation of PFAA precursors during remediation included elevated ratios of perfluorohexanesulfonate (PFHxS) to PFOS in groundwater near oxygen sparging wells.
Seven‐day sublethal toxicity tests were performed with the freshwater invertebrates Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus to determine the effects of per‐ or polyfluorinated ...alkyl substances (PFAS) of varying chain length within four classes: perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs), perfluoroalkane sulfonamides, and fluorotelomer sulfonic acids. In general, toxicity increased with increasing chain length, but the slopes of these relationships varied markedly by species and chemical class. The toxicity of individual PFCAs was similar among species. The toxicity of PFSAs was similar to PFCAs for C. dubia and H. azteca, whereas PFSAs were much more toxic to C. dilutus, with median effect concentrations (EC50s) as low as 0.022 mg perfluorooctane sulfonate (PFOS)/L and 0.012 mg perfluorononane sulfonate (PFNS)/L. Despite the high sensitivity to PFOS and PFNS, C. dilutus was not very sensitive to structurally similar fluorotelomer sulfonates (6:2 and 8:2). Perfluoroalkane sulfonamides were the most toxic class tested among all species (e.g., EC50s of 0.011 and 0.017 mg perfluorooctane sulfonamide/L for C. dilutus and H. azteca, respectively). The differences in toxicity among species and chemical classes suggest that mechanisms of PFAS toxicity may differ as a function of both. Environ Toxicol Chem 2024;43:359–373. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.
Environmental analysis by large-volume injection (LVI) was compared to solid-phase extraction (SPE) based methods using matrix effects as a quantitative indicator of analytical signal quality. LVI ...was performed by the direct injection of 900 μL of wastewater onto a high-performance liquid chromatography (HPLC) column while SPE-based methods utilized octadecyl silane (C18) and hydrophobic-lypophilic balance (HLB) solid phases to preconcentrate wastewater prior to analysis. Model analytes from three classes of environmental contaminants were selected for study including four estrogens (estrone, estradiol, estriol, and ethinylestradiol), eight perfluoroalkyl carboxylates (C4–C11), and five perfluoroalkyl sulfonates (C4, C6–C8, and C10). The matrix effects on analytes were assessed by two approaches (quantitatively by calculating percent matrix effects and qualitatively with postcolumn infusions) and compared across LVI- and SPE-based methods at constant (high and low) analyte-to-matrix mass ratios. The results from this study demonstrated that the LVI-based method produced analytical signals of quality similar to the two SPE-based methods. Furthermore, LVI presented a clear advantage over SPE because it was performed at lower cost, required fewer materials, involved less labor and eliminated the analyte loss associated with SPE.
A new method was developed for the analysis of natural and synthetic androgenic steroids and their selected metabolites in aquatic environmental matrixes using direct large-volume injection (LVI) ...high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). Method accuracy ranged from 87.6 to 108% for analytes with well-matched internal standards. Precision, quantified by relative standard deviation (RSD), was less than 12%. Detection limits for the method ranged from 1.2 to 360 ng/L. The method was demonstrated on a series of 1 h composite wastewater influent samples collected over a day with the purpose of assessing temporal profiles of androgen loads in wastewater. Testosterone, androstenedione, boldenone, and nandrolone were detected in the sample series at concentrations up to 290 ng/L and loads up to 535 mg/h. Boldenone, a synthetic androgen, had a temporal profile that was strongly correlated to testosterone, a natural human androgen, suggesting its source may be endogenous. An analysis of the sample particulate fraction revealed detectable amounts of sorbed testosterone and androstenedione. Androstenedione sorbed to the particulate fraction accounted for an estimated 5 to 7% of the total androstenedione mass.
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