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The vast number of chemicals potentially reaching aquatic environment pose a challenge in maintaining the quality of water resources. However, best management practices to improve water quality are typically focused on reducing nutrient transport without assessing how these practices may impact the occurrence of micropollutants. The potential for co-management of nutrients and organic micropollutants exists, but few studies have comprehensively evaluated the suite of contaminants associated with different water quality management practices (riparian zone restoration, stormwater management, etc.). Furthermore, most studies dealing with the determination of micropollutants in environmental samples include only a limited number of target analytes, leaving many contaminants undetected. To address this limitation, there has been a gradual shift in environmental monitoring from using target analysis to either suspect screening analysis (SSA) or non-targeted analysis (NTA), which relies on accurate mass measurements, mass spectral fragmentation patterns, and retention time information obtained using liquid chromatography coupled to high-resolution mass spectrometry. The work presented in this paper focuses on a wide-scope detection of micropollutants in surface water samples from the Potomac River watershed (United States). An in-house database composed of 1039 compounds based on experimental analysis of primary standards was established, and SSA workflow was optimized and applied to determine the presence of micropollutants in surface water. A total of 103 micropollutants were detected in the samples, some of which are contaminants that were not previously monitored and belong to various classes such as pharmaceuticals, personal care products, per-and polyfluoroalkyl substances and other persistent industrial chemicals. The impact of best management practices being implemented for nitrogen and phosphorus reductions were also assessed for their potential to reduce micropollutant transport. This work illustrates the advantages of suspect screening methods to determine a large number of micropollutants in environmental samples and reveals the potential to co-manage a diverse array of micropollutants based on shared transport and transformation mechanisms in watersheds., Highlights • In-house suspect screening database that include 1039 micropollutants was developed • Suspect screening analysis (SSA) workflow was optimized to increase chemical coverage • SSA detected 103 micropollutants in the samples collected from Potomac watershed • BMPs result in co-management of nutrients and micropollutants transport

The present study focuses on the determination of the occurrence and levels of per- and polyfluoroalkyl substances (PFASs) in the drinking and source water from the Philippines and Thailand. A total of 46 samples (18 commercial bottled waters, 5 drinking water from vending machine (re-fill stations) and 23 source water) were analyzed using liquid chromatography with tandem high-resolution mass spectrometry. Using the targeted method, 12 different PFASs were detected in the drinking water samples with total quantifiable PFASs (∑PFASs) levels ranging from 7.16 to 59.49 ng/L; 15 PFASs were detected in source water with ∑PFASs ranging from 15.55 to 65.65 ng/L. A 100% detection frequency was observed for perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorosulfonic acid (PFOS) in all water samples. Six other PFASs, not included in the targeted analysis, were detected using the suspect screening approach. For the first time, the presence of 2-(N-methylperfluorooctanesulfonamido) acetic acid (N-MeFOSAA) in drinking water is reported, and 3 novel PFASs (C5H5OF8, C6H4O2F6, and C9H2O2F16) were detected using suspect screening in source water. Combined results from target and suspect screening analysis showed that PFASs detected were predominantly (52%) short-chain (with fluorinated alkyl chain of ≤6) which could be explained by their high mobility in the environment. The detected PFASs levels in drinking water will not likely pose immediate health risk to consumers according to US EPA health advisory for PFOS and PFOA of 70 ng/L, but inclusion of bottled and drinking water from re-fill stations in monitoring programs is warranted.

Application of animal manure on agricultural lands is one of the main sources of estrogen contamination in the environment. Poultry and cow manure contain free and conjugated forms of the natural estrogens (e.g., estrone [E1] and estradiol [E2]) that can enter surface waters during runoff events. Estrone has been identified as the major form of estrogen in the environment; therefore, this study is focused on the evaluation of the degree of mineralization and fate of E1 in a simulated poultry litter and cow manure runoff water. A time-course study was conducted using simulated runoff water that consisted of 0.5 mg cow manure or poultry litter dissolved in 1 L of water spiked with radiolabeled E1 (C-E1). Samples were analyzed for estrogen concentrations at Day 0, 0.5, 1, 2, 3, 5, and 7 using liquid chromatography with tandem mass spectrometry. In the poultry litter simulated runoff water, E1 was biotransformed to 17β-estrone-3-sulfate (E1-3S) but was eventually mineralized to CO; a total E1 mineralization of 92.2% occurred after 7 d of aerobic incubation. In contrast, the concentrations of E1 and other forms of endogenous estrogens detected in the cow manure simulated runoff water, such as E1-3S, 17α-estradiol (α-E2), and 17β-estradiol (β-E2), remained relatively constant and persisted over the 7 d of aerobic incubation. Results of this study demonstrate the differences in the fate of estrone in the simulated poultry litter and cow manure runoff water, highlighting the ability of the endogenous microbial community from poultry litter to mineralize estrogens to CO.

Perfluorooctane sulfonate (PFOS) is a member of the anthropogenic class of perfluorinated alkyl acids (PFAAs) and one of the most frequently detected PFAAs in water, humans, mammals, and fish around the world. The zebrafish (Danio rerio) is a small freshwater fish considered an appropriate vertebrate model for investigating the toxicity of compounds. Previous investigations showed tissue-specific bioaccumulation and alterations in the expression of fatty acid-binding proteins (fabps) in male and female zebrafish, potentially due to interactions between PFAA and fatty acid transporters. In addition, a number of neurological impacts have been reported as a result of human and animal exposure to PFAAs. Therefore, the present comprehensive study was designed to investigate whether PFOS exposure affects the expression of genes associated with fatty acid metabolism (fabp1a, fabp2, and fabp10a) in zebrafish liver, intestine, heart, and ovary and genes involved in the nervous system (acetylcholinesterase, brain-derived neurotrophic factor, choline acetyltransferase, histone deacetylase 6, and nerve growth factor) in brain and muscle. The results indicate alterations in expression of genes associated with fatty acid metabolism and neural function that vary with both exposure concentration and sex. In addition, our findings highlight that expression of these genes differs according to exposure duration. The present results extend the knowledge base on PFOS effects to other tissues less often studied than the liver. The findings of the present investigation provide a basis for future studies on the potential risks of PFOS as one of the most abundant PFAAs in the environment. Environ Toxicol Chem 2020;39:437-449. © 2019 SETAC.

Chromatographic retention factors (k) and mass spectral fragmentation patterns of per- and polyfluoroalkyl substances (PFASs) were determined using the optimized parameters in liquid chromatography with tandem high-resolution mass spectrometry (LC-HRMS) analysis. Characteristic fragment ions obtained at various collision energies (MS2 fragmentation) were used to determine the structures of newly discovered (emerging) PFASs detected from industrial effluent and surface water samples. Moreover, COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) derived octanol-water partition coefficients (Kow), along with mean isotropic polarizabilities calculated from Density Functional Theory (DFT), of known PFASs were plotted against their experimental k values (kexp) to obtain a multivariable regression model that can be used to predict k values of unknown PFASs. The k values of different structural isomers of unknown PFASs were calculated and compared to kexp. The predicted k value for the isomer that matches the MS2 fragmentation observed was found to be within 4.2 % of kexp. This study demonstrates the applicability of an approach that combines the observed MS2 fragmentation patterns and k values, together with computationally-derived log Kow and polarizabilities, in assigning the structures of unknown PFASs at environmentally relevant conditions when no reference standards are available.