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While organic-diffusive gradients in thin films (o-DGT) passive samplers have been used to assess organic contaminants in water, the effects of biofouling on accurate analyte quantification by o-DGT are poorly understood. We evaluated the effects of biofouling on the uptake of six common perfluoroalkyl substances (PFAS) using a previously developed polyacrylamide-WAX (weak anion exchange) o-DGT without a filter membrane. Linear uptake (

Non-steroidal anti-inflammatory drugs are recognized widely as emerging contaminants. Sulindac has received additional attention as a prodrug in cancer treatment and because of its detection in drinking water and wastewaters. Nevertheless, there is limited knowledge about its kinetic behaviour and fate in the aquatic environment. In this work, the direct photolysis of sulindac, in which photochemical reactions were monitored and phototransformation products identified, was investigated under prolonged periods using UV-A and UV-B radiation and pH conditions (2 and 7) to evaluate the effect of the protonation state and the efficiency of the photolytic process. A novel kinetic mechanism has been proposed in which sulindac exhibits a consecutive reaction pathway, with pseudo-first order kinetics for rapid and reversible Z to E isomerization. Once photoequilibrium was reached, second-order degradation of the isomers in the presence of the new photodegradation products was observed. Photochemical transformation was faster under UV-B irradiation and lower pH, which suggests greater persistence of sulindac at more relevant environmental conditions of UV-A and pH 7. Two novel and major byproducts were identified, corresponding to the oxidative cleavage of the alkene exo to the indene system. The degradation pathway is mainly photoinduced, enhanced by acidic conditions and presumes the double bond as the most reactive site for the parent compound. This research demonstrates an approach for determining kinetics of compounds under challenging conditions, including, absorption from multiple electronic transitions, photoinduced products with unknown extinction coefficients, concentration dependence, photoinduced sensitizing intermediates, and speciation effects. Our work greatly improves our understanding of the degradation process of sulindac and will contribute to exposure assessments and treatment methodologies for this compound in impacted waters.

The presence of microcystins (MCs) in waterbodies requires a simple and reliable monitoring technique to characterize better their spatiotemporal distribution and ecological risks. An organic-diffusive gradients in thin films (o-DGT) passive sampler based on polyacrylamide diffusive gel and hydrophilic-lipophilic balance (HLB) binding gel was developed for MCs in water. The mass accumulation of three MCs (MC-LR, –RR, and -YR) was linear over 10 days (R2 ≥ 0.98). Sampling rates (2.68–3.22 mL d−1) and diffusion coefficients (0.90–1.08 × 10−6 cm2 s−1) of three MCs were obtained at 20 °C. Two different passive samplers, o-DGT and the Solid Phase Adsorption Toxin Tracking device (SPATT), were co-deployed to estimate MC levels at three lakes in California, USA. Measured total MC concentrations were up to 10.9 μg L−1, with MC-LR the primary variant at a measured maximum concentration of 2.74 μg L−1. Time-weighted average MC concentrations by o-DGT were lower than grab water samples, probably because grab sampling measures both dissolved and particulate phases (i.e., MCs in cyanobacteria). Passive water samplers by design can only measure dissolved-phase MCs, which are considerably less during the cyanobacteria-laden periods observed. Both o-DGT and grab samples gave comparable results for three MC variants at low levels of MCs, e.g.

With the growth of both the pharmaceutical industry and the human population and longevity, more drugs are used and processed each day. Inevitably, these pharmaceuticals enter wastewater through human excretion and improper disposal of leftovers. One such medication, diltiazem, a calcium channel blocker, is of importance due to its widespread consumption, and prevalence in aquatic environments. To study the sub-lethal effects of diltiazem on aquatic animals, we investigated its impacts no feeding behaviour, heart rate, respiration, growth, and reproduction of a bioindicator species, Daphnia magna. When exposed to environmentally relevant concentrations, D. magna increased their heart rate by 12% and oxygen consumption by 48%. However, exposure did not have any effects on thoracic limb movement frequency or peristalsis (i.e. feeding behaviour). Individuals exposed to diltiazem for a longer duration (16 days) showed a 44% decrease in lipid reserves and produced between 17 and 28% fewer neonates which were 10–12% larger. Our study demonstrated that exposure to diltiazem creates an energy imbalance in D. magna which could, in the long run, influence their populations.

The impacts of microplastics on aquatic ecosystems and biota are gaining attention globally. Although microplastics have been widely detected in biota, there currently are few standardized detection and identification methods. The present study developed a novel one-step digestion method which was evaluated with mussel and fish samples. This method employed nitric acid and hydrogen peroxide (HNO3 :H2 O2 = 4:1 by volume) as digestion reagents, which completely digested biota samples 0.05) were observed for all tested polymers. Fourier transform infrared spectral analyses demonstrated that the method did not degrade any of the polymers except for polyethylene terephthalate. The method was demonstrated with mussel and fish samples collected from the Pearl River delta, south China, and was able to recover microplastics effectively. Overall, the present method is time-saving and easy to operate, with low procedural cross-contamination. The properties of microplastics recovered by the present method remained largely intact, greatly benefiting subsequent qualitative and quantitative analyses. Environ Toxicol Chem 2019;38:1400-1408. © 2019 SETAC.

California Senate Bill 1422 requires the development of State-approved standardized methods for quantifying and characterizing microplastics in drinking water. Accordingly, we led an interlaboratory microplastic method evaluation study, with 22 participating laboratories from six countries, to evaluate the performance of widely used methods: sample extraction via filtering/sieving, optical microscopy, FTIR spectroscopy, and Raman spectroscopy. Three spiked samples of simulated clean water and a laboratory blank were sent to each laboratory with a prescribed standard operating procedure for particle extraction, quantification, and characterization. The samples contained known amounts of microparticles within four size fractions (1-20 μm, 20-212 μm, 212-500 μm,500 μm), four polymer types (PE, PS, PVC, and PET), and six colors (clear, white, green, blue, red, and orange). They also included false positives (natural hair, fibers, and shells) that may be mistaken for microplastics. Among laboratories, mean particle recovery using stereomicroscopy was 76% ± 10% (SE). For particles in the three largest size fractions, mean recovery was 92% ± 12% SD. On average, laboratory contamination from blank samples was 91 particles (± 141 SD). FTIR and Raman spectroscopy accurately identified microplastics by polymer type for 95% and 91% of particles analyzed, respectively. Per particle, FTIR spectroscopy required the longest time for analysis (12 min ± 9 SD). Participants demonstrated excellent recovery and chemical identification for particles greater than 50 μm in size, with opportunity for increased accuracy and precision through training and further method refinement. This work has informed methods and QA/QC for microplastics monitoring in drinking water in the State of California.

The use of recycled glass as a substrate for constructed wetlands was assessed through two studies. The first study examined the dissipation of atenolol, carbamazepine, and sulfamethoxazole in mesocosm-modeled wetlands using glass or limestone gravel as substrates, with or without cattails (Typha spp.). Following pseudo-first-order kinetics, atenolol dissipated the fastest from the water surface of the mesocosms (t

The application of the organic-diffusive gradients in thin films (o-DGT) passive sampling technique for the monitoring of per- and polyfluoroalkyl substances (PFAS) in the environment is still limited. Six common PFAS with different chain lengths were evaluated in water by o-DGT. Measured diffusion coefficients (D) in agarose and polyacrylamide diffusive gels ranged from 4.55–8.63 × 10−6 cm2 s−1 and 3.85–7.00 × 10−6 cm2 s−1 at 23 °C, respectively. Experimental sampling rates (Rs) for both agarose- and polyacrylamide-WAX sampler configurations were within 22% relative error of D-based Rs for four of the PFAS. Larger differences for perfluorobutanesulfonic acid (PFBS) and perfluoroundecanoic acid (PFUnDA) ranged from 36% to 56%. In general, in-situ Rs can be predicted using measured D-values for perfluorinated alkyl acids. The mass accumulation of six PFAS in two o-DGT configurations was linear over 21 days (R2 ≥ 0.97). Diffusion and uptake of o-DGT depended on the gel type and specific PFAS. Field demonstrations of o-DGT with WAX and HLB binding gels and polyacrylamide diffusive gels (not prone to biodegradation) found 0.3–19.5 ng L−1 of PFAS in rivers near industrial areas around Guangzhou and Foshan, China, with no apparent differences between the two co-deployed samplers. This study demonstrates that the configurations of o-DGT tested provide a cost-effective monitoring tool for measuring perfluorinated alkyl acids in aquatic systems, in particular the four PFAS for which reasonable correlations were observed.

The chemical composition of water-soluble organics in oil sands process-affected water (OSPW) is primarily composed of natural constituents of bitumen that are solubilized and concentrated during aqueous extraction of oil sands. OSPW organics are persistent and acutely toxic, and a leading remediation strategy is long-term ageing in end-pit lakes, despite limited data available on its photochemical fate. Here, direct photolysis of whole OSPW, or of its constituent fractions, was examined at environmentally relevant wavelengths (>290 nm) in bench-top studies. Changes in the chemical profiles of whole OSPW, acid- (AEO), and base-extractable organics (BEO) were characterized by liquid chromatography with ultra-high resolution mass spectrometry in negative (-) and positive (+) ionization modes. Following 18 d of irradiation, photolysis reduced the total ion intensity in all samples in both modes. The most photo-labile species included the O2-, O3-, O4-, O2S-, and O4S- chemical classes, which were depleted in whole OSPW by 93-100% after only 5 d. In positive mode, detected species were more recalcitrant than those detected in negative mode, with an average reduction across all heteroatomic classes of 75 ± 11.0% after 18 d. Estimated environmental half-lives for heteroatomic classes ranged from 57 d (O4S-) to 545 d (O3N+), with a greater recalcitrance for classes detected in positive mode compared to negative mode. Under field conditions in end-pit lakes, natural photolysis may be an important mechanism for effective OSPW remediation, and we suggest that future end-pit lakes be shallow to maximize light penetration and natural photolysis in ageing OSPW.

Some pharmaceutical conjugates can be excreted into wastewaters at levels rivalling those of the parent compounds; however, little is known about this potential reservoir of pharmaceuticals to aquatic systems. We evaluated the occurrence and distribution of four different classes of pharmaceuticals and their metabolite conjugates in a wastewater treatment plant over four months. Aqueous and suspended solids fractions of primary, mixed liquor, secondary, and final effluent, along with return activated sludge, and waste activated sludge were assessed. The only conjugate not found in the final effluent was acetaminophen sulfate. Moreover, thyroxine and thyroxine glucuronide were the only compounds quantified in the suspended solids in the final effluent. Propranolol, propranolol sulfate, thyroxine, and thyroxine glucuronide all had no significant decreases in concentration going through the wastewater treatment process, from primary to final effluent. However, there were significant decreases observed for acetaminophen (99.8%), sulfamethoxazole (71%), N-acetyl sulfamethoxazole (59%), and sulfamethoxazole glucuronide (79%). The mean (±SEM) mass loadings in the aqueous fraction of the final effluent for each compound ranged from 0.84 ± 0.2 g/d for thyroxine to 45.3 ± 4.2 g/d for acetaminophen. At least as much conjugate was released into receiving waters, if not more: 1.6 ± 0.2 g/d for thyroxine glucuronide to 18.5 ± 4.5 g/d for sulfamethoxazole glucuronide, and 61.2 ± 9.6 g/d for N-acetyl sulfamethoxazole. Additionally, the mean loading of thyroxine was 0.29 ± 0.025 g/day and thyroxine glucuronide 1.8 ± 0.59 g/day in the suspended solids. This equates to 26% of total thyroxine and 53% of total thyroxine glucuronide associated with suspended particulate matter that reaches receiving waters. This study reflects the importance of including phase II conjugates in assessing overall compound load of pharmaceutical discharge from wastewaters, and also that substantial amounts of such contaminants are associated with wastewater solids when drugs are in the pg/L to μg/L range.

The organic-diffusive gradients in thin-films (o-DGT) technique has emerged as a promising aquatic passive sampler that addresses many of the challenges associated with current sampling tools used for measurement of polar organic contaminants. This study represents the first comprehensive field evaluation of the o-DGT in natural surface waters, across a wide suite of polar pharmaceuticals and pesticides. We explore the utility and limitations of o-DGT as a quantitative measurement tool compared to grab sampling and the polar organic chemical integrative sampler (POCIS) across four connected agricultural and wastewater-influenced freshwater systems spanning 600 km from the U.S. border to northern Manitoba, Canada. Overall, the suite of analytes detected with o-DGT and POCIS was similar. Concentrations in water estimated using o-DGT were greater than concentrations estimated from POCIS in 71 of 80 paired observations, and on average, the estimates from o-DGT were 2.3-fold greater than estimates from POCIS. Grab sample concentrations suggested that the systematic underestimation with POCIS were largely a result of sampling rate variation related to flow rate and boundary-layer effects, an issue reported consistently in the POCIS literature. These comprehensive measurements in an agriculturally influenced fast-flowing river, long-term sampling (>40 days) in a large dilute lake system, deployments in wastewaters, and under ice at near-freezing temperatures represent effective stress testing of o-DGT under representative and challenging conditions. Overall, its strong performance and improved accuracy over POCIS supports its use as a robust, quantitative, and sensitive measurement tool for polar organic chemicals in aquatic systems.

The Red River originates in the U.S., drains into Lake Winnipeg, and is a significant pathway for nutrients. We investigate its role as a source for pesticides, pharmaceuticals, per- and polyfluoroalkyl substances (PFASs) substances (PFASs), and microbes bearing antibiotic resistance genes (ARGs). We delineate agricultural, urban, and rural land-use for organic contaminants to determine the extent of chemical transboundary riverine fluxes, and characterize levels and trends of organic contaminants and ARGs between spring and fall 2014 and 2015. The herbicide atrazine peaked at over 500 ng/L (14-day time weighted average) near the border, indicating that the U.S. represents the major source into Canada from the Red River. Neonicotinoid insecticides had relatively constant concentrations, suggesting more widespread agricultural use in both countries. Pesticide concentrations were greatest post-application in June and July. Mass loadings of pesticides over the sampling periods, from the river to Lake Winnipeg, ranged from approximately 800 kg of atrazine, to 120 kg of thiamethoxam and clothianidin, to 40 kg of imidacloprid. Exposure distributions for atrazine exceeded benchmark water quality guidelines for protection of aquatic life (0.2% probability of exceeding chronic benchmark) with no exceedances for neonicotinoids. Seven pharmaceuticals were detected, mostly at low ng/L levels downstream of the City of Winnipeg wastewater treatment plant. Carbamazepine, the only pharmaceutical detected consistently at all sites, contributed on average 20 kg each year into Lake Winnipeg. While minor inputs were observed all along the river, city inputs represented the greatest source of pharmaceuticals to the river. Both PFASs and ARGs were observed consistently and ubiquitously, indicative of an anthropogenically influenced system with no indications of any single point-source signature. While transboundary flux from the U.S. was an important source of pesticides to the Red River, especially for atrazine, observed concentrations of all measured contaminants suggest that known aquatic toxicological risk is minimal.

Occurrence of microplastics (MPs) in the environment has attracted great attention as it has become a global concern. This review aims to systematically demonstrate the role of marine microplastic as a novel medium for environmental partitioning of chemicals in the ocean, which can cause toxic effects in the ecological environment. This review assimilated and analyzed available data published between 1972 and 2017 on the interaction between MPs and selected chemicals. Firstly, the review analyzes the occurrence of chemicals in MPs and outlines their distribution patterns. Then possible mechanisms of the interaction between MPs and organic chemicals and potential controlling factors were critically studied. Finally, the hazards of MPs and affiliated organic chemicals to marine organisms were shortly summarized.

An increasing number of reports have been published concerning microplastic (MP) pollution in aquatic environments. Methods used in these studies continue to be updated and lack standardization, so that an up-to-date review pertaining methods for MP research is needed. This critical review examines the analytical methods, including sampling, identification, and quantitation, for MP research. Samples are generally collected from water, sediment, and biota gastrointestinal tract. Manta nets or trawls are prevalently used in surface water sampling, while direct shoveling or box-corer grab are commonly applied in sediment sampling. Microplastics in biota are generally obtained by dissecting organisms and separating livers, gills, and guts. Density separation is frequently chosen to separate MPs from sample matrices. Chemical digestion can dissolve other organic materials and isolate MPs for further identification. Visual sorting should be combined with chemical composition analysis to better identify the polymer type. Pyrolysis or thermal decomposition gas chromatography coupled with mass spectrometry, Fourier transform infrared spectroscopy, and Raman spectroscopy are currently the main technologies for MP identification. Units prevalently used to express MP abundance in water, sediment, and biota are “particles per m3,” “particles per m2,” and “particles per individual,” respectively. As MP abundances often varied with the methods used, we recommend that analytical protocols of MPs should better be standardized and optimized. Despite the important progress in analysis of MPs, detection technologies for identifying nano-sized plastic particles are still lacking, and therefore should be developed swiftly.

Gemfibrozil, a common lipid regulator, enters aquatic environments through treated municipal wastewater effluent that fails to remove it completely from effluent streams. When exposed to gemfibrozil concentrations of 50, 500, 5,000, and 50,000 ng L−1, Daphnia magna showed increased lipid reserves by 14–21% (significant at 500 ng L−1), increased length by 9–13% (significant at 50 ng L−1), increased mass by 6–13% (significant at 50 ng L−1) and increased neonate production by 57–74% (significant at 50 ng L−1). Gemfibrozil-exposed Daphnia held under conditions where food availability was low, grew and reproduced as well as those in the control. Taken together, these results suggest that gemfibrozil exposure within environmentally relevant concentration ranges is not toxic to Daphnia magna but has the potential to be beneficial to the species under these conditions.

A solids extraction method, using sonication in combination with weak anion exchange solid phase extraction, was created to extract thyroxine (T4) and thyroxine-O-β- d -glucuronide (T4-Glc) simultaneously from wastewaters and sludges, and to quantify these compounds via reversed-phase ultra-high performance liquid chromatography-tandem mass spectrometry. The method limits of quantification were all in the low ng/g (dry weight solids) range for both T4 and T4-Glc: 2.13 and 2.63 ng/g respectively in primary wastewater, 4.3 and 28.3 ng/g for primary suspended solids, for 1.1 and 3.7 ng/g for return activated sludge. Precision for measurements of T4 and T4-Glc were 2.6 and 6.5% (intraday) and 9.6 and 5.7% (interday) respectively, while linearity was 0.9967 and 0.9943 respectively. Overall recoveries for T4 and T4-Glc in primary suspended solids were 94% and 95%, and 86 and 101% in primary wastewater, respectively. Extraction efficiency tests using primary sludge determined that one methanol aliquot was sufficient during the extraction process as opposed to 2 or 3 aliquots. Mass loadings at the North Main Wastewater Treatment Plant in Winnipeg, Canada showed 316%, 714%, and 714% greater T4-Glc than T4 associated with the suspended solids of the primary, secondary, and final effluent respectively, yet 765% more T4 than T4-Glc associated with the solids of the mixed liquor. Moreover, 26% of T4 and 49% of T4-Glc were associated with the suspended solids during the treatment process. This method demonstrates the need to assess accurately both metabolite conjugates of contaminants of emerging concern, as well as the sorbed levels of particle-reactive analytes such as T4 in the aquatic environment.

The fate of selected common pharmaceuticals and four of their major conjugates in wastewater batch bioreactors was evaluated to determine how treatment plant parameters such as addition of air, and the presence of waste activated sludge (WAS) could influence the removal of parent compounds and conjugates. Under a realistic hydraulic residence time (HRT) for each treatment sub-process of approximately 2 h, acetaminophen and its sulfate metabolite were both rapidly degraded (99%). Propranolol was sulfated and concurrently removed. Deconjugation of N-acetylsulfamethoxazole and sulfamethoxazole-glucuronide contributed to increases of the parent sulfamethoxazole. Thyroxine was resistant to degradation, while thyroxine-glucuronide was rapidly deconjugated (90% in2 h). In the absence of WAS, sorption to suspended solids was another major removal mechanism for acetaminophen, propranolol, sulfamethoxazole, and thyroxine. However, with WAS, concentrations associated with suspended solids decreased for all analytes within 24 h. These results indicate that both conjugation and back-transformation are compound-specific and dependent on parameters such as HRT, addition of microbial content, and suspended solids levels. Therefore, conjugation-deconjugation processes may strongly influence the speciation of pharmaceuticals and their fate in wastewater treatment plant effluents.

Passive sampling techniques have been widely used to determine the dissolved concentration profiles of hydrophobic organic compounds (HOCs) in sediment porewater. However, the effects of having a protection for the passive sampler on profiling HOCs concentrations in sediment porewater, especially in deep sediment, have remained unclear. To address this issue, low density polyethylene passive samplers with and without protectors, which consisted of glass fiber filter and porous stainless steel shield, were simultaneously deployed in sediment of the Dongjiang River, South China. The results showed that the protectors retarded the dissipation of performance reference compounds (PRCs) from the sampler by a factor of 2–9. The protectors seemed to exert a negligible effect on the measured concentrations of PAHs, BDE-47, and BDE-99 in surficial sediment porewater (0–14 cm depth) from both samplers. However, the sediment porewater concentration profiles of PAHs and BDE-47 from the sampler with protectors were in agreement with those normalized by dry weight in deep sediment (16–34 cm depth), indicating that a diffusion layer established by the protectors may minimize the probability of local depletion of the target analytes in deep sediment. In addition, the log Koc values of PAHs, BDE-47, and BDE-99 exhibited a slight increasing trend with sediment depth. This finding suggested that in situ passive sampling techniques could be a feasible tool in determining the site-specific log Koc values of HOCs at different sediment depths.

Aerated lagoons, typically used by small communities, often provide limited removal of wastewater nutrients. Given increasingly stringent wastewater standards, it is imperative that effective, but economical and easy-to-operate, treatment technologies be developed. The Submerged Attached Growth Reactor (SAGR®) is a treatment process developed to perform nitrification near freezing temperatures. Previous tests on full-scale installations have shown that SAGR could consistently remove ammonia to below current Canadian standards and provide additional total suspended solids and biochemical oxygen demand removal. In this study, we evaluated removal of polar chemicals of emerging concern (CECs), including pharmaceuticals, personal care products, and pesticides, at SAGR installations in two Manitoba First Nations communities (MCN and LPFN) under cold winter conditions. Both showed some removal of diclofenac, naproxen, clarithromycin, metoprolol, and trimethoprim, likely by biotransformation. Average naproxen removal was 21% (2.53 × 103 ng L−1) in MCN and 64% (1.58 × 103 ng L−1) in LPFN. Atenolol was well-removed by SAGR, by 80% on average (range of 64%–94%). Clarithromycin, metoprolol, and trimethoprim removal was similar within and between systems, ranging from 54% to 76% (30.8–3.07 × 102 ng L−1 removed). Carbamazepine was detected in nearly all samples, but was not well-removed, consistent with other treatment studies. Overall, results showed that SAGR technology could moderately remove CECs, while providing the designed treatment performance for other parameters. This work will help to improve our understanding of wastewater treatment in small and/or remote communities with limited infrastructure and challenging cold-weather conditions.

Effective removal of organic contaminants in wastewater effluent poses a challenge to small communities worldwide, particularly in the Arctic due to infrastructure challenges and harsh climates. To understand better the efficacy of current treatment options and risks posed by pharmaceuticals and pesticides on receiving waters in the Arctic, four representative human communities in Nunavut, Canada were evaluated. Per- and polyfluorinated alkyl substances (PFASs) were also investigated in one community. These communities have treatment ranging from primary lagoons, engineered wetlands, and natural lakes. Pharmaceuticals and pesticides were measured using the organic diffusive gradients in thin film (o-DGT) passive sampler in summer 2018. Of the 34 compounds studied, seven pharmaceuticals were found at least once: atenolol, carbamazepine, metoprolol, naproxen, sulfapyridine, sulfamethoxazole, and trimethoprim. With the exception of 5210 ng naproxen/L in Iqaluit, most receiving waters showed negligible amounts of contamination. Iqaluit had the poorest overall system performance while Baker Lake had the best. Measured pharmaceutical concentrations do not appear to pose a significant acute hazard to receiving waters at this time, based on known toxicological endpoints. PFAS concentrations were found to be over 100-fold greater in Cambridge Bay wastewater than previously reported Arctic seawater. Results suggest that wastewater may be an important point source of PFASs in Arctic communities. The o-DGT passive samplers performed well in marine Arctic settings. We recommend further testing of wastewater efficiencies in Arctic communities along with evaluations of seasonal variations.

Estrogenically active compounds (EACs) in surface waters can disrupt the endocrine system of biota, raising concern for aquatic species. Concentrations of EACs are generally higher in effluent-dominated aquatic systems, such as California's Santa Ana River (SAR). Addressing estrogenicity of effluent-dominated waters is increasingly important due to both increasing urbanization and climate change. To this end, water samples were collected from multiple sites downstream of wastewater treatment plants (WWTPs) and intermittent points along the SAR during 2018–2019 and cell-based bioassays were used to determine estrogen receptor activity. During baseflow conditions, the highest estradiol equivalencies (EEQs) from all SAR water between summer (August and September) and fall (November) sampling events in 2018 were from Yorba Linda (EEQ = 1.36 ± 0.38 ng/L) and Prado (1.14 ± 0.13 ng/L), respectively. Water extracts in January 2019 following a major rainfall generally had higher EEQs with the highest EEQ of 10.0 ± 0.69 ng/L observed at Yorba Linda. During low flow conditions in November 2018, male Japanese medaka (Oryzias latipes) fish were exposed to SAR water to compare to cell bioassay responses and targeted analytical chemistry for 5 steroidal estrogens. Chemical-based EEQ correlations with in vitro EEQs were statistically significant. However, vitellogenin (vtg) mRNA expression in the livers of medaka exposed to SAR water was not significantly different compared to controls. These results indicate that seasonal variation and surface water runoff events influence estrogenic activity in the SAR and may induce estrogenic effects to native fish populations in wastewater-dominated streams in general.

Recent data suggests there are non-trivial amounts of human pharmaceutical conjugates potentially entering environmental surface waters. These compounds could contribute to eliciting toxic effects on aquatic biota either directly or indirectly, via de-conjugation. The need for developing a single method for quantifying both parents and conjugates is necessary. Propranolol (PRO), sulfamethoxazole (SMX), and their respective major conjugates 4-OH-propranolol sulfate (PRO-Sul) and sulfamethoxazole-β-glucuronide (SMX-Glc) were successfully simultaneously extracted through weak anion exchange solid phase extraction cartridges from primary and secondary clarification wastewaters from the North End Winnipeg Water Pollution Treatment Plant in Winnipeg, Canada. Subsequent separation and quantification were achieved by reversed-phase C18 chromatography coupled to positive electrospray ionisation tandem mass spectrometry. Linearity for all compounds throughout the 7-point calibration range was >0.99. Recovery RSD ranges across all matrices for PRO, SMX, PRO-Sul, and SMX-Glc were 2.1–13.2%, 2.3–10.2%, 9.8–19.2%, and 2.0–10.3% respectively. Primary and secondary filtrates respectively showed a significant increase of PRO from 0.039 to 0.045 μg/L; a significant decrease for SMX from 1.56 to 0.58 μg/L; significant decrease of PRO-Sul from 0.050 to 0.020 μg/L; and a significant decrease of SMX-Glc from 0.41 to 0.019 μg/L. These observations indicate that there was removal of all compounds, except for PRO, from the aqueous phase occurring at some point between the stages of treatment. To our knowledge, this is first study that simultaneously separated and quantified two different classes of parent compounds and two different kinds of human metabolite conjugates (glucuronide and sulfate) from a major urban wastewater treatment plant.

Mass transfer of hydrophobic organic contaminants (HOCs) across the air-water interface is an important geochemical process controlling the fate and transport of HOCs at the regional and global scales. However, few studies have characterized concentration or fugacity profiles of HOCs near both sides of the air-water interface, which is the driving force for the inter-compartmental mass transfer of HOCs. Herein, we introduce a novel passive sampling device which is capable of measuring concentration (and therefore fugacity) gradients of HOCs across the air-water interface. Laboratory studies indicated that the escaping fugacity values of polycyclic aromatic hydrocarbons (PAHs) from water to air were negatively correlated to their volatilization half-lives. Results for field deployment were consistent between the passive sampler and an active method, i.e., a combination of grab sampling and liquid-liquid extraction. In general, the fugacity profiles of detected PAHs were indicative of an accumulation mechanism in the surface microlayer of the study regions (Haizhu Lake and Hailing Bay of Guangdong Province, China), while p,p'-DDD tended to volatilize from water to the atmosphere in Hailing Bay. Furthermore, the fugacity profiles of the target analytes increased towards the air-water interface, reflecting the complexity of environmental behavior of the target analytes near the air-water interface. Overall, the passive sampling device provides a novel means to better characterize the air-water diffusive transfer of HOCs, facilitating the understanding of the global cycling of HOCs.

Although passive sampling is widely accepted as an excellent tool for environmental monitoring, their integration with suspect or non-targeted screening by high-resolution mass spectrometry has been limited. This study describes the application of the organic-diffusive gradients in thin-films (o-DGT) passive sampler as a tool for accurate measurement of both targeted and suspect polar organic contaminants (primarily pharmaceuticals) in wastewater. First, performance of o-DGT was assessed alongside the polar organic chemical integrative sampler (POCIS) and active sampling at two wastewater treatment facilities using targeted analyses. Overall, water concentrations measured by o-DGT, POCIS, and 24-hr integrative active samples were in good agreement with each other. There were exceptions, including a systematic difference between o-DGT and POCIS at certain sites that we propose was a result of site-specific conditions and a difference in sampling rates between the two techniques. The second component of this work involved suspect screening of the o-DGT extracts using high-resolution, high mass accuracy quadrupole time-of-flight mass spectrometry (QTOF). Lamotrigine, venlafaxine, and des-methylvenlafaxine were three suspect compounds identified and selected as proof-of-concept case studies to determine the feasibility and accuracy of o-DGT for estimating water concentrations based upon predicted sampling rates using a previously validated o-DGT diffusion model. Semi-quantification of the suspect compounds was conducting using an average surrogate response factor based on the suite of compounds measured by the targeted analyses. This, combined with the modelled sampling rates provided time-weighted average wastewater concentrations of the identified suspects within a factor of 2 of the true value, confirmed by isotope dilution with mass labelled internal surrogates. To the knowledge of the authors, this work is the first to demonstrate the utility of the o-DGT passive sampler as a potential environmental screening tool that can be integrated into the rapidly advancing field of non-targeted high resolution mass spectrometry.

Thiamethoxam is a neonicotinoid insecticide that can reach wetlands in agro-ecosystems through runoff. The fate and effects of thiamethoxam on non-target organisms in shallow wetland ecosystems have not been well characterized. To this end, a mesocosm study was conducted with a focus on characterizing zooplankton community responses. A single pulse application of thiamethoxam (0, 25, 50, 100, 250, and 500 μg/L; n = 3) was applied to experimental systems and monitored for 8 weeks. The mean half-life of thiamethoxam among the different treatments was 3.7 days in the water column with concentrations of0.8 μg/L in the majority of mesocosms by 56 days. Principal response curve analysis did not show any significant concentration-dependent differences in the zooplankton community among treatments over the course of the study. The minimum detectable difference (MDD%) values for abundance of potentially sensitive arthropod taxa (nauplius larvae, cyclopoid copepods) allowed the detections from controls as low as 42 and 59% effect, respectively. The MDD% values for total abundance of zooplankton (including the potentially less sensitive taxonomic group of Rotifera) allowed the detection from controls as low as 41% effect. There were no statistically significant differences in zooplankton abundance or diversity between control and treated mesocosms at the end of the study. There were also no statistically significant differences for individual taxa that were sustained between sampling points, or manifested as a concentration-response. We conclude that acute exposure to thiamethoxam at environmentally relevant concentrations (typically ng/L) likely does not represent a significant adverse ecological risk to wetland zooplankton community abundance and structure.

In the present study, we report the freezer storage stability of pharmaceuticals and pesticides for the organic-diffusive gradients in thin-films (o-DGT) passive sampler and the polar organic chemical integrative sampler (POCIS). The average change on o-DGT after approximately 18 mo was 9 ± 9% across 30 compounds. For POCIS, the average change after approximately 6 yr was 14 ± 14% for the same compounds. Our data suggest that analytes stored on these samplers are stable and appropriate for archival purposes. Environ Toxicol Chem 2018;37:762-767. © 2017 SETAC.

Organic contaminants, in particular persistent organic pollutants (POPs), adversely affect water quality and aquatic food webs across the globe. As of now, there is no globally consistent information available on concentrations of dissolved POPs in water bodies. The advance of passive sampling techniques has made it possible to establish a global monitoring program for these compounds in the waters of the world, which we call the Aquatic Global Passive Sampling (AQUA-GAPS) network. A recent expert meeting discussed the background, motivations, and strategic approaches of AQUA-GAPS, and its implementation as a network of networks for monitoring organic contaminants (e.g., POPs and others contaminants of concern). Initially, AQUA-GAPS will demonstrate its operating principle via two proof-of-concept studies focused on the detection of legacy and emerging POPs in freshwater and coastal marine sites using both polyethylene and silicone passive samplers. AQUA-GAPS is set up as a decentralized network, which is open to other participants from around the world to participate in deployments and to initiate new studies. In particular, participants are sought to initiate deployments and studies investigating the presence of legacy and emerging POPs in Africa, Central, and South America.

Sediment has been recognized as a gigantic sink of organic materials and therefore can record temporal input trends. To examine the impact of anthropogenic activities on the marginal seas off China, sediment cores were collected from the Yellow Sea, the inner shelf of the East China Sea (ECS), and the South China Sea (SCS) to investigate the sources and spatial and temporal variations of organic materials, i.e., total organic carbon (TOC) and aliphatic hydrocarbons. The concentration ranges of TOC were 0.5-1.29, 0.63-0.83, and 0.33-0.85%, while those of Σn-C14-35 (sum of n-alkanes with carbon numbers of 14-35) were 0.08-1.5, 0.13-1.97, and 0.35-0.96 μg/g dry weight in sediment cores from the Yellow Sea, ECS inner shelf, and the SCS, respectively. Terrestrial higher plants were an important source of aliphatic hydrocarbons in marine sediments off China. The spatial distribution of Σn-C14-35 concentrations and source diagnostic ratios suggested a greater load of terrestrial organic materials in the Yellow Sea than in the ECS and SCS. Temporally, TOC and Σn-C14-35 concentrations increased with time and peaked at either the surface or immediate subsurface layers. This increase was probably reflective of elevated inputs of organic materials to marginal seas off China in recent years, and attributed partly to the impacts of intensified anthropogenic activities in mainland China. Source diagnostics also suggested that aliphatic hydrocarbons were mainly derived from biogenic sources, with a minority in surface sediment layers from petroleum sources, consistent with the above-mentioned postulation.

The stability of 24 chemicals, including pharmaceuticals and personal care products, and some agrochemicals on extraction media was evaluated by preloading them onto Oasis hydrophilic lipophilic balanced solid-phase extraction (SPE) cartridges and polar organic chemical integrative samplers (POCIS) followed by storage at –20°C over time. After 20 months, the average loss was 11% on POCIS, with only 2,4-dichlorophenoxyacetic acid, atrazine, chlorpyrifos, and gemfibrozil showing a statistically significant decline compared with initial concentrations. Losses on SPE cartridges were below 19%, with an average loss of 9%. In addition to laboratory spiked samples, multiple POCIS deployed in wastewater-impacted surface waters and SPE extracts of these waters were stored in their original coextracted matrix for nearly two years with minimal observed losses. Errors from typical sampling, handling, and concentration estimates from POCIS sampling rates were typically ± 15 to 30% relative standard deviation, so observed storage losses are minimal for most POCIS applications. While losses during storage on SPE cartridges for 20 months were small but statistically significant for many compounds, addition of labeled internal standards prior to freezing should correct for such losses. Thus, storage of processed water samples for analysis of polar organic pollutants is viable for archival purposes or studies for which samples cannot be analyzed in the short term. Environ. Toxicol. Chem. 2013;32:337–344. © 2012 SETAC

Artículo The treatment of municipal wastewater in the Arctic is challenging due to a variety of financial, operational, climatic and technical issues. To better understand the efficacy of current wastewater treatment in this region and the hazard posed to receiving waters, we assessed the occurrence of nutrients and contaminants (i.e., pharmaceuticals, antibiotic resistance genes) as they moved through a lagoon-based treatment system in Cambridge Bay, Nunavut, Canada. Wastewater treatment in this community is performed by the use of a lagoon-tundra wetland system that is discharged into the marine environment and is representative of current common practices throughout the region. In 2014, samples were collected before and during lagoon discharge from two locations in the main lagoon, one location downstream from the lagoon effluent and three locations offshore. Grab samples were collected to measure nutrients (e.g., total nitrogen and phosphorus) and the presence of antibiotic resistance genebearing microbes, and Polar Organic Chemical Integrative Samplers (POCIS) were deployed to collect passively organic contaminants in all locations. A total of six pharmaceuticals were detected from a screen of twenty-eight analytes during the study: atenolol, carbamazepine, clarithromycin, metoprolol, sulfamethoxazole and trimethoprim. The greatest concentrations of nutrients, antibiotic resistance genes (ARGs), and pharmaceuticals were found in sampling locations within the treatment lagoon. Offshore of the release point, we observed limited to no detection of pharmaceuticals and ARGs, but no change in total nitrogen and phosphorus from pre-release. We conclude that the current concentrations of monitored pharmaceuticals do not pose a significant hazard at this time to aquatic organisms in Cambridge Bay.

Sources, compositions, and historical records of polycyclic aromatic hydrocarbons (PAHs) in sediment cores collected from the Yellow Sea and the South China Sea were analyzed to investigate the influence of anthropogenic activities. The occurrence of PAHs was mainly derived from various combustion sources, especially the combustion of biomass and domestic coal. Uniform composition of sedimentary PAHs (52-62% of phenanthrene, benzo[b]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[g,h,i]perylene) suggested air-borne mixtures intractable to degradation. The concentrations of the sum of 15 PAHs (16 priority pollutants designed by the United States Environmental Protection Agency minus naphthalene; designed as Σ(15)PAH) in Yellow Sea sediment cores were generally higher than those in the South China Sea. The profiles of Σ(15)PAH concentrations recorded in the sediment cores closely followed historical socioeconomic development in China. In general, Σ(15)PAH concentrations started to increase from the background pollution level posed by agricultural economy at the turn of 20th century. In addition, a Σ(15)PAH concentration reduction was observed during the Chinese Civil War (1946-1949) and Great Cultural Revolution (1966-1976), suggesting them as setbacks for economic development in Chinese history. Increasing PAH emissions as a result of increasing coal combustion associated with the rapid urbanization and industrialization since the implementation of the Reform and Open Policy (since 1978) accounted for the fast growth of Σ(15)PAH concentrations in sediment cores. The decline of Σ(15)PAH concentrations from subsurface maximum until sampling time was inconsistent with current-day economic development in China, and may possibly suggest emission reductions due to decreasing proportional use of domestic coal and increasing consumption of cleaner energies (natural gas and liquefied petroleum gas).

To investigate the potential for enantioselective transformation and accumulation, the enantiomer distributions of seven polychlorinated biphenyl (PCB) atropisomers were measured in the sediment and biota from a sub-tropical estuary heavily contaminated with Aroclor 1268, a technical mixture of highly chlorinated PCB congeners. Enantiomer fractions (EFs) of PCBs 91, 95, 136, 149, 174, 176, and 183 in marsh sediment, invertebrate, forage and predatory fish species, and bottlenose dolphins were determined. Non-racemic EFs greater than 0.75 were found in sediments for PCBs 136 and 174, likely the result of microbial dechlorination. Although enantiomer fractions in grass shrimp (Palaemonetes spp.) mirrored those of sediment, fish species had EFs that differed significantly from sediment or grass shrimp. Similarly, bottlenose dolphins were also found to contain non-racemic quantities of PCBs 91, 136, 174, 176, and 183. Non-racemic EFs in these biota were likely a result of both uptake of non-racemic proportions of PCBs from the diet and enantioselective biotransformation.

A reversed-phase enantioselective liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method was developed to measure enantiomer fractions (EF) and concentrations of pharmaceuticals in wastewater. Enantiomer resolution of six beta-blockers (atenolol, metoprolol, nadolol, pindolol, propranolol, and sotalol) along with two selective serotonin re-uptake inhibitors (citalopram, fluoxetine) and one beta(2)-agonist (salbutamol) was achieved with the Chirobiotic V stationary phase. Analyte recovery averaged 86% in influent and 78% in effluent with limits of detection ranging from 0.2 to 7.5 ng/L. These results represent an improvement in wastewater EF measurement for atenolol, metoprolol and propranolol as well as the first EF measurements of citalopram, fluoxetine, nadolol, pindolol, salbutamol and sotalol in wastewaters. Changes in EF through treatment indicate biologically mediated stereoselective processes were likely occurring during wastewater treatment.

The New York/New Jersey Harbor Estuary is subject to significant contamination of polychlorinated biphenyls (PCBs) from numerous sources, including the historically contaminated Upper Hudson River, stormwater runoff and sewer overflows, and atmospheric deposition from PCBs originating from the surrounding urban area. However, the relative importance of these sources to the estuary's food web is not fully understood. Sources of PCBs to the estuary were apportioned using chiral signatures of PCBs in air, water, total suspended matter, phytoplankton, and sediment. PCBs 91, 95, 136, and 149 were racemic in the atmosphere of the estuary. However, the other phases contained nonracemic PCB 95 and to a lesser extent PCB 149. Thus, the predominant atmospheric source of these congeners is likely unweathered local pollution and not volatilization from the estuary. The similarity in chiral signatures in the other phases is consistent with dynamic contaminant exchange among them. Chiral signatures in the dissolved phase and total suspended matter were correlated with Upper Hudson discharge, suggesting thatthe delivery of nonracemic contaminated sediment from the Upper Hudson, not the atmosphere, controls phytoplankton uptake of some PCBs. Thus, measures to control PCB contamination in the Upper Hudson should be effective in reducing loadings to the estuary's aquatic ecosystem.

The fate of six human-use drugs was assessed and predicted in mesocosms designed to mimic shallow constructed wetlands during the onset of fall and senescence. Mesocosms were monitored for 28 days after the addition of carbamazepine, clofibric acid, fluoxetine and naproxen (nominal initial concentrations of 5 μg/L each), sulfamethoxazole, and sulfapyridine (nominal initial concentrations of 150 μg/L each), with and without phosphorous (P) addition at 1.6 mg/L. We hypothesized that addition of P would stimulate primary productivity and enhance removal of pharmaceuticals from the water column. Carbamazepine, clofibric acid, fluoxetine, and naproxen had half-lives of 8.7, 11, 1.5, and 2.5, and 8.6, 11.0, 1.4, and 2.5 days in treatments with and without P amendment, respectively. Sulfamethoxazole and sulfapyridine had half-lives of 17 and 4.9 days in mesocosms with P amendment and 17 and 4.7 days without amendment. A concurrent pulse of P with pharmaceuticals did not significantly enhance the removal of these compounds. Predicted half-lives from modeling efforts were consistent with observed values, with photolysis the greatest contributor to chemical attenuation.

Accumulation and elimination of chiral polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides by the opossum shrimp, Mysis relicta, was investigated to determine if zooplankton can stereoselectively process chiral OC contaminants. Concentrations and enantiomer fractions were measured within mysids over a 10-day exposure followed by a 45-day depuration period. Rapid accumulation occurred within mysids exposed to sediment contaminated with racemic chiral OC compounds at microg/g levels. Enantiomer enrichment was observed within mysids for the second-eluting enantiomer and the (-)-enantiomer of PCB 95 and trans-chlordane, respectively, after 7 days of exposure to spiked sediment, and for the second-eluting enantiomers of PCBs 91 and 183 and (-)-PCB 149 over longer time periods. Enantiomer fractions decreased with time during the depuration phase of the experiment for these compounds, showing that their elimination from mysids was stereoselective. Oxychlordane was detected in nonracemic proportions after exposure, indicating that mysids can metabolize trans-chlordane enantioselectively. Minimum elimination rates calculated were higher than biotransformation rates calculated for fish in previous studies, which have been shown to metabolize OC contaminants. This study is the first to show stereoselective processing of chiral OC contaminants by aquatic invertebrates.

The enantioselectivity of microbial reductive dechlorination of chiral PCBs in sediments from Lake Hartwell, SC, was determined by microcosm studies and enantiomer-specific GC analysis. Sediments from two locations in the vicinity of the highest levels of PCB contamination were used as inocula. Dechlorination activity was monitored by concentration decreases in the spiked chiral PCBs and formation of dechlorination products using both achiral and chiral chromatography. Live microcosms spiked with PCB132 (234-236) exhibited dechlorination of PCB132 to PCB91 (236-24) and PCB51 (24-26). Meta dechlorination was the dominant mechanism. Microcosms spiked with PCB149 (245-236) exhibited preferential para dechlorination of PCB149 to PCB95 (236-25), followed by meta dechlorination to PCB53 (25-26) and subsequently PCB19 (26-2). Dechlorination of chiral PCB132 and PCB149 was not enantioselective. In Aroclor 1254-spiked microcosms, reductive dechlorination of PCB149 also was nonenantioselective. These results suggest that dechlorinating enzymes responsible for the dehalogenation of the chiral PCB132 and PCB149 congeners bind the two enantiomers equally. Reductive dechlorination of PCB91 and PCB95, however, occurred in an enantioselective manner, indicating that the dechlorinating enzymes for these PCBs are enantiomer-specific. The chlorine substitution pattern on the biphenyl ring appears to influence whether reductive dechlorination of chiral PCB congeners is enantioselective. Enantioselective PCB dechlorination by the microbial population of Lake Hartwell sediments occurs for select chiral PCBs; thus, certain chiral PCBs might be useful as markers for in situ reductive dechlorination.

Dietary accumulation of four chiral organochlorine compounds--alpha-hexachlorocyclohexane (alpha-HCH), trans-chlordane, and chlorobiphenyls (CBs) 95 and 136-by immature rainbow trout (Oncorhynchus mykiss) was studied to determine if fish can accumulate and eliminate these compounds enantioselectively. Fish rapidly accumulated all four compounds from food spiked at micrograms per gram concentrations during a 40-d feeding period. Depuration half-lives were from 13 d for (+/-)-alpha-HCH to 375 d for (+/-)-CB 136. Fish preferentially eliminated (-)-trans-chlordane and (+)-CB 136, with significant nonracemic residues observed after 20 d. These results are consistent with field measurements of these compounds in fish as well as known metabolic pathways. Enantiomeric fractions (EFs) for these two compounds changed significantly over the course of the experiment, suggesting that trout were enantioselectively biotransforming the compounds during the 238-d depuration phase. CB 95 and alpha-HCH residues were racemic throughout the experiment. High biomagnification factors for CB 95 suggest that it was not metabolized. Minimum values for metabolic elimination rates calculated from EF suggest that at least 58% of the trans-chlordane depuration rate can be attributed to metabolism, and all of the CB 136 depuration rate can be attributed to it. This study highlights the potential of chiral analysis as a tracer of in vivo biotransformation processes of xenobiotic compounds.

A probabilistic ecological risk assessment was conducted for the transformation products (TPs) of 3 β-blockers (atenolol, metoprolol, and propranolol) and 5 selective serotonin reuptake inhibitors (SSRIs; citalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline) to assess potential threats to aquatic organisms in effluent-dominated surface waters. To this end, the pharmacokinetic literature, the University of Minnesota's Biocatalysis/Biodegradation Database Pathway Prediction System aerobic microbial degradation software, and photolysis literature pertaining to β-blockers and SSRIs were used to determine their most likely TPs formed via human metabolism, aerobic biodegradation, and photolysis, respectively. Monitoring data from North American and European surface waters receiving human wastewater inputs were the basis of the exposure characterizations of the parent compounds and the TPs, where available. In most cases, where monitoring data for TPs did not exist, we assumed a conservative 1:1 parent-to-TP production ratio (i.e., 100% of parent converted). The US Environmental Protection Agency (USEPA)'s EPISuite and ECOSAR v1.11 software were used to estimate acute and chronic toxicities to aquatic organisms. Hazard quotients, which were calculated using the 95(th) percentile of the exposure distributions, ranged from 10(-11) to 10(-3) (i.e., all significantly less than 1). Based on these results, the TPs of interest would be expected to pose little to no environmental risk in surface waters receiving wastewater inputs. Overall, we recommend developing analytical methods that can isolate and quantify human metabolites and TPs at environmentally relevant concentrations to confirm these predictions. Further, we recommend identifying the major species of TPs from classes of pharmaceuticals that could elicit toxic effects via specific modes of action (e.g., norfluoxetine via the serotonin 5-hydroxytryptamine [5-HT]1A receptors) and conducting aquatic toxicity tests to confirm these findings. To our knowledge, this is the first quantitative probabilistic ecotoxicological assessment of all of the predicted and probable TPs of these pharmaceuticals, and our approach provides a framework for future such studies with other compound classes as data become available.

Polychlorinated biphenyls (PCBs) chiral signatures were measured in Greenland sharks (Somniosus microcephalus) and their potential prey in arctic marine food webs from Canada (Cumberland Sound) and Europe (Svalbard) to assess temporal and spatial variation in PCB contamination at the stereoisomer level. Marine mammals had species-specific enantiomer fractions (EFs), likely due to a combination of in vivo biotransformation and direct trophic transfer. Greenland sharks from Cumberland Sound in 2007-2008 had similar EFs to those sharks collected a decade ago in the same location (PCBs 91, 136 and 149) and also similar to their conspecifics from Svalbard for some PCB congeners (PCBs 95, 136 and 149). However, other PCB EFs in the sharks varied temporally (PCB 91) or spatially (PCB 95), suggesting a possible spatiotemporal variation in their diets, since biotransformation capacity was unlikely to have varied within this species from region to region or over the time frame studied. © 2013 Elsevier Ltd. All rights reserved.

Enantiomeric ratios (ERs) for eight polychlorinated biphenyl (PCB) atropisomers were measured in aquatic sediment from selected sites throughout the United States by using chiral gas chromatography/mass spectrometry. Nonracemic ERs for PCBs 91, 95, 132, 136, 149, 174, and 176 were found in sediment cores from Lake Hartwell, SC, which confirmed previous inconclusive reports of reductive dechlorination of PCBs at these sites on the basis of achiral measurements. Nonracemic ERs for many of the atropisomers were also found in bed-sediment samples from the Hudson and Housatonic Rivers, thus indicating that some of the PCB biotransformation processes identified at these sites are enantioselective. Patterns in ERs among congeners were consistent with known reductive dechlorination patterns at both river sediment basins. The enantioselectivity of PCB 91 is reversed between the Hudson and Housatonic River sites, which implies that the two sites have different PCB biotransformation processes with different enantiomer preferences.

Outdoor shallow wetland mesocosms, designed to simulate surface constructed wetlands to improve lagoon wastewater treatment, were used to assess the role of macrophytes in the dissipation of wastewater nutrients, selected pharmaceuticals, and antibiotic resistance genes (ARGs). Specifically, mesocosms were established with or without populations of Typha spp. (cattails), Myriophyllum sibiricum (northern water milfoil), and Utricularia vulgaris (bladderwort). Following macrophyte establishment, mesocosms were seeded with ARG-bearing organisms from a local wastewater lagoon, and treated with a single pulse of artificial municipal wastewater with or without carbamazepine, clofibric acid, fluoxetine, and naproxen (each at 7.6μg/L), as well as sulfamethoxazole and sulfapyridine (each at 150μg/L). Rates of pharmaceutical dissipation over 28d ranged from 0.073 to 3.0d(-1), corresponding to half-lives of 0.23 to 9.4d. Based on calculated rate constants, observed dissipation rates were consistent with photodegradation driving clofibric acid, naproxen, sulfamethoxazole, and sulfapyridine removal, and with sorption also contributing to carbamazepine and fluoxetine loss. Of the seven gene determinants assayed, only two genes for both beta-lactam resistance (blaCTX and blaTEM) and sulfonamide resistance (sulI and sulII) were found in sufficient quantity for monitoring. Genes disappeared relatively rapidly from the water column, with half-lives ranging from 2.1 to 99d. In contrast, detected gene levels did not change in the sediment, with the exception of sulI, which increased after 28d in pharmaceutical-treated systems. These shallow wetland mesocosms were able to dissipate wastewater contaminants rapidly. However, no significant enhancement in removal of nutrients or pharmaceuticals was observed in mesocosms with extensive aquatic plant communities. This was likely due to three factors: first, use of naive systems with an unchallenged capacity for nutrient assimilation and contaminant removal; second, nutrient sequestration by ubiquitous filamentous algae; and third, dominance of photolytic processes in the removal of pharmaceuticals, which overshadowed putative plant-related processes.

Exposure to perfluorooctane sulfonate (PFOS) may arise directly, from emission and exposure to PFOS itself, or indirectly via the environmental release and degradation of PFOS-precursors. Human serum enantiomer fractions (EFs) of 1m-PFOS have been shown to be nonracemic, suggesting that PFOS-precursors are a significant source of PFOS in humans, but little is known about the importance of PFOS-precursors in ecosystems. In the current work, concentrations of PFOS, perfluorooctane sulfonamide (PFOSA), PFOS isomer profiles, and EFs of 1m-PFOS were determined in Lake Ontario water, sediment, fishes and invertebrates. Concentrations of PFOS and PFOSA were highest in slimy sculpin and Diporeia, and concentrations of the two compounds were often correlated. 1m-PFOS was racemic in sediment, water, sculpin and rainbow smelt, but nonracemic in the top predator, lake trout, and all invertebrate species. Furthermore, EFs were correlated with the relative concentrations of PFOS and PFOSA in invertebrates. Overall, these empirical observations with a new analytical tool confirm previous suggestions that PFOS-precursors contribute to PFOS in the food web, likely via sediment. Implications are that future PFOS exposures in this ecosystem will be influenced by an in situ source, and that the apparent environmental behavior of PFOS (e.g., bioaccumulation potential) can be confounded by precursors.

Multiple geochemical markers, including aliphatic hydrocarbons (n-alkanes), linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs), were employed to relate sediment organic chemical pollution in the coastal zone off South China to socioeconomic development there. Concentrations of Σn-C(15-35) (n-alkanes with 15-35 carbon atoms), ΣLAB (sum of C(10) to C(13) LABs), and Σ(26) PAH (sum of 26 PAH compounds) ranged from 110 to 3,160, 11 to 160, and 26 to 600 ng/g, with medians of 730, 40, and 230 ng/g, respectively. Natural hydrocarbons were mainly derived from terrestrial higher plant waxes, and in minor amounts from aquatic plankton and bacteria. Compositions of LABs indicated that considerable amounts of poorly treated wastewater had been directly discharged or transported to the eastern and western coastal areas of Guangdong Province. In addition, anthropogenic hydrocarbons were derived largely from vehicular emissions and combustion of domestic coal and biomass and to a lesser extent from oil spills. Eastern and western coastal sediments contained higher levels of LABs but lower levels of PAHs than those of the Pearl River Estuary, a coastal area of the Pearl River Delta. This spatial pattern of organic pollution was consistent with chemical use patterns. The eastern and western regions of Guangdong Province are economically less developed than the Pearl River Delta region, where more domestic wastewater treatment plants have been built. However, greater amounts of energy are consumed in the latter region to produce more combustion-derived PAH contamination.

Both ecosystem and human health rely on clean, abundant supplies of water, thus many classes of potential pollutants are regulated. In recent years, the possible risks associated with largely uncontrolled inputs of pharmaceuticals to rivers, lakes, groundwater, and coastal waters, mainly via wastewater, have been a focus of much research. During this time, our capacity to sequester, identify, and quantify pharmaceuticals in environmental matrices has improved. Devices have emerged to allow passive uptake of drugs to augment or replace laborious grab sampling. Advances in sample preparation have streamlined extraction procedures and removed interfering matrix components. New instrumental techniques have allowed faster, more accurate and sensitive detection of drugs in water samples. This review highlights all of these advances, from sample collection to instrumental analysis, which will continue to help us better understand the fate and effects of pharmaceuticals in aquatic systems.

Enantiomer fractions (EFs) of seven chiral polychlorinated biphenyls (PCBs) were measured in dated sediment cores of Lake Hartwell (SC, USA) and Lake Ontario (USA) to detect, quantify, and gain insight regarding microbial reductive dechlorination of PCBs in lake sediments with high and low concentrations, respectively. Lake Hartwell sediments had high total PCBs (5-60 microg/g), with significantly nonracemic EFs that generally were consistent with those from previous laboratory microcosm reductive dechlorination experiments using sediments from these sites. Thus, stereoselective reductive dechlorination had occurred in situ, including at total PCB concentrations of less than the threshold of approximately 30 to 80 microg/g suggested as being necessary for reductive dechlorination. Enantiomer fractions of PCBs 91, 95, 132, and 136 in Lake Hartwell cores were significantly correlated both with concentrations of those individual congeners and with total PCB concentration for some sites. This result indicates that enantioselective microbial dechlorination activity increases with higher concentrations within sediments for these congeners. Enantiomer composition reversed with depth for PCBs 91, 132, and 176, suggesting that multiple microbial populations may be present within the same core that are enantioselectively dechlorinating PCBs. Such observations indicate that concentration and time are not the only factors affecting biotransformation, complicating prediction of enantioselectivity. Comparison of EFs with dates suggested biotransformation half-lives of approximately 30 years, which is on the same time scale as sequestration by burial. In contrast, Lake Ontario sediments (maximum total PCBs, 400 ng/g) had racemic or near-racemic amounts of most congeners throughout the core profile, which is consistent with achiral indicators suggesting no microbial biotransformation within Lake Ontario sediments. Thresholds for reductive dechlorination may exist, but they would be at concentrations of less than 30 to 80 microg/g.

In this work, we optimize a solid phase microextraction (SPME) method for the simultaneous collection of antibiotics (sulfonamides, macrolides, and trimethoprim) present in wastewaters. The performance of the SPME method is compared to a solid phase extraction (SPE) method. Analytes in both cases were quantified by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) with electrospray ionization. The advantages offered by SPME in this application are: decreased sample volume requirements, ease of sample processing and extraction, decreased cost, and most importantly, elimination of electrospray matrix effects. Despite having higher limits of quantification (16-1380 ng/L in influent and 35-260 ng/L in effluent), nearly all of the compounds found to be present in Edmonton Gold Bar wastewater by SPE were measurable by SPME (i.e., sulfamethoxazole, trimethoprim, erythromycin, and clarithromycin), with values similar to those obtained using the former method. Limits of quantification for the SPE method for the measured compounds were 4.7-15 ng/L and 0.86-6.1 ng/L for influent and effluent, respectively.

Hydroxylated PCBs (OH-PCBs) are a class of organic contaminants that have been found recently in the plasma of Great Lakes fish, the source of which is either bioformation from PCBs or accumulation from the environment. To address the potential for fish to biotransform PCBs and bioform OH-PCBs juvenile rainbow trout (Oncorhynchus mykiss; ∼80 g) were exposed to dietary concentrations of an environmentally relevant mixture of PCBs. Eight OH-PCBs were found in the plasma of rainbow trout after 30 days of exposure to the PCBs, the relative pattern of which was similar to those observed in wild lake trout (Salvelinus namaycush) from Lake Ontario. Hydroxylated-PCBs were not found (detection limit 0.02 pg/g) in the food or control (not PCB-exposed) fish. A curvilinear log t1/2-log Kow relationship for recalcitrant PCBs was found, similar to previously reported relationships, although t1/2 values were longer and shorter than studies using smaller fish or cooler temperatures, respectively. A number of PCB congeners fell below the log t1/2-log Kow relationship providing the first estimates of non-chiral PCB biotransformation rates in fish. Enantioselective degradation of the chiral congeners PCBs 91 and 136, also indicated biotransformation. Biotransformation of PCBs was structure-dependent with greater biotransformation of PCBs with vicinal hydrogen atoms in the meta/para positions, suggesting CYP 2B-like biotransformation. Other chiral congeners with a meta/para substitution pattern showed no enantioselective degradation but were biotransformed based on the log t1/2-log Kow relationship. The results of this study demonstrate that laboratory held rainbow trout can biotransform a number of PCB congeners and that bioformation is likely an important source of OH-PCBs in wild salmonids of the Great Lakes. © 2006 Elsevier B.V. All rights reserved.

The enantiomer composition of six chiral polychlorinated biphenyls (PCBs) were measured in three different certified Standard Reference Materials (SRMs) from the US National Institute of Standards and Technology (NIST): SRM 1946 (Lake Superior fish tissue), SRM 1939a (PCB Congeners in Hudson River Sediment), and SRM 2978 (organic contaminants in mussel tissue--Raritan Bay, New Jersey) to aid in quality assurance/quality control methodologies in the study of chiral pollutants in sediments and biota. Enantiomer fractions (EFs) of PCBs 91, 95, 136, 149, 174, and 183 were measured using a suite of chiral columns by gas chromatography/mass spectrometry. Concentrations of target analytes were in agreement with certified values. Target analyte EFs in reference materials were measured precisely (2% relative standard deviation), indicating the utility of SRM in quality assurance/control methodologies for analyses of chiral compounds in environmental samples. Measured EFs were also in agreement with previously published analyses of similar samples, indicating that similar enantioselective processes were taking place in these environmental matrices.

This work presents a critical assessment of the state and quality of knowledge around the aquatic photochemistry of human- and veterinary-use pharmaceuticals from laboratory experiments and field observations. A standardized scoring rubric was used to assess relevant studies within four categories: experimental design, laboratory-based direct and indirect photolysis, and field/solar photolysis. Specific metrics for each category are defined to evaluate various aspects of experimental design (e.g., higher scores are given for more appropriate characterization of light source wavelength distribution). This weight of evidence-style approach allowed for identification of knowledge strengths and gaps covering three areas: first, the general extent of photochemical data for specific pharmaceuticals and classes; second, the overall quality of existing data (i.e., strong versus weak); and finally, trends in the photochemistry research around these specific compounds, e.g. the observation of specific and consistent oversights in experimental design. In general, those drugs that were most studied also had relatively good quality data. The four pharmaceuticals studied experimentally at least ten times in the literature had average total scores (lab and field combined) of ≥29, considered decent quality; carbamazepine (13 studies; average score of 31), diclofenac (12 studies; average score of 31), sulfamethoxazole (11 studies; average score of 34), and propranolol (11 studies; average score of 29). Major oversights and errors in data reporting and/or experimental design included: lack of measurement and reporting of incident light source intensity, lack of appropriate controls, use of organic co-solvents in irradiation solutions, and failure to consider solution pH. Consequently, a number of these experimental parameters were likely a cause of inconsistent measurements of direct photolysis rate constants and quantum yields, two photochemical properties that were highly variable in the literature. Overall, the assessment rubric provides an objective and scientifically-defensible set of metrics for assessing the quality of a study. A major recommendation is the development of a method guideline, based on this rubric, for conducting and reporting on photochemical studies that would produce consistent and reliable data for quantitative comparison across studies. Furthermore, an emphasis should be placed on conducting more dual-fate studies involving controlled photolysis experiments in natural sunlight, and whole system fate studies in either natural or artificial systems. This would provide accurate data describing the actual contribution of photolysis to the overall fate of pharmaceuticals in the environment.