Publications by authors named "Kevin Stroski"

6 Publications

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Plasma Vitellogenin Reveals Potential Seasonal Estrogenicity in Fish from On-Site Wastewater Treatment Systems in Semi-Arid Streams Influenced by Snowmelt.

Bull Environ Contam Toxicol 2020 Nov 10;105(5):692-698. Epub 2020 Oct 10.

Department of Environmental Science and Center for Reservoir and Aquatic Systems Research, Baylor University, One Bear Place #97266, Waco, Texas, 76798, USA.

Effluents from on-site wastewater treatment systems can influence surface water quality, particularly when infrastructure is aging, malfunctioning, and improperly installed. Municipal wastewater often contains chemical compounds that can lead to adverse biological effects, such as reproductive impairment, in organisms that are chronically exposed. A significant number of these compounds are endocrine-disrupting chemicals. Water quality influences of on-site systems are poorly studied in semi-arid regions where instream flows are seasonally dependent on snowmelt, and when instream dilution of wastewater effluents is minimal during other times of the year. Here we examined surface water estrogenicity in low order tributaries of two unique semi-arid streams with on-site wastewater treatment systems, for which seasonal instream flow fluctuations occur in Park City, UT, USA. Water samples were collected from a total of five locations along two lotic systems downstream from active on-site treatment systems. Samples were extracted for targeted chemical analyses and to perform in vivo and in vitro bioassays with juvenile rainbow trout. Estrogenic activity was measured by quantifying the concentration and expression of vitellogenin (VTG) in plasma and liver, respectively. Plasma VTG presented elevated levels in fish exposed to water samples collected at the two sites in close proximity to on-site systems and during seasons with low stream discharge, though the levels observed did not suggest severe endocrine disruption. However, long-term exposure to these surface water could compromise the fish populations. While the sensitivity of in vitro bioassays was low and targeted chemical analyses did not identify causative compounds, the use of complementary lines of evidence (e.g., in vivo biological models) was advantageous in identifying estrogenic activity in waters influenced by effluents from on-site wastewater systems.
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http://dx.doi.org/10.1007/s00128-020-03021-6DOI Listing
November 2020

Multi-approach assessment for the evaluation of spatio-temporal estrogenicity in fish from effluent-dominated surface waters under low instream flow.

Environ Pollut 2020 Oct 27;265(Pt B):115122. Epub 2020 Jun 27.

Department of Environmental Science and Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX, 76798, USA. Electronic address:

Current practices employed by most wastewater treatment plants (WWTP) are unable to completely remove endocrine disrupting compounds (EDCs) from reclaimed waters, and consistently discharge these substances to receiving systems. Effluent-dominated and dependent surface waters, especially during low instream flows, can increase exposure and risks to aquatic organisms due to adverse biological effects associated with EDCs. Given the ecological implications that may arise from exposure to such compounds, the present a multi-approach study examined spatio-temporal estrogenic potential of wastewater effluent to fish in East Canyon Creek (ECC), Utah, USA, a unique urban river with instream flows seasonally influenced by snowmelt. Juvenile rainbow trout (Oncorhynchus mykiss) were caged at different upstream and downstream sites from an effluent discharge during the summer and fall seasons. In the summer, where approximately 50% of the streamflow was dominated by effluent, fish from the upstream and a downstream site, located 13 miles away from the effluent discharge, presented significantly elevated concentrations of plasma vitellogenin (VTG). Similarly, significantly high 17β-estradiol to 11-ketotestosterone ratios were measured in the summer across all sites and time points, compared to the fall. In the laboratory, juvenile fish and primary hepatocytes were exposed to concentrated effluent and surface water samples. Quantification of VTG, although in significantly lower levels, resembled response patterns observed in fish from the field study. Furthermore, analytical quantification of common EDCs in wastewater revealed the presence of estriol and estrone, though these did not appear to be related to the observed biological responses, as these were more significant in sites were no EDCs were detected. These combined observations suggest potential estrogenicity for fish in ECC under continuous exposures and highlight the advantages of following weight-of-evidence (WoE) approaches for environmental monitoring, as targeted analytically-based assessments may or may not support the identification of causative contaminants for adverse biological effects.
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http://dx.doi.org/10.1016/j.envpol.2020.115122DOI Listing
October 2020

8:8 Perfluoroalkyl phosphinic acid affects neurobehavioral development, thyroid disruption, and DNA methylation in developing zebrafish.

Sci Total Environ 2020 Sep 26;736:139600. Epub 2020 May 26.

Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX 76706, USA; Institute of Biomedical Studies, Baylor University, Waco, TX 76706, USA. Electronic address:

Recent studies have reported potential neurotoxicity and epigenetic alteration associated with exposure to several per- and polyfluoroalkyl substances (PFASs). However, such information is limited to a few compounds (e.g., perfluorooctane sulfonate), primarily based on rodent experiments, and the underlying toxicological mechanism(s) for many PFAS in the environment remain poorly understood. In the present study, we investigated 8:8 perfluoroalkyl phosphinic acid (8:8 PFPiA), an under-studied PFAS with high persistency in the environment and biota, using the zebrafish model. We exposed zebrafish embryos (<4 hpf) to various concentrations of 8:8 PFPiA (0, 0.0116, 0.112, 0.343, 1.34, 5.79 μM) for 144 h. Although there was no significant change in survival, hatchability and malformations, zebrafish locomotor speed at 120 h significantly decreased in dark photoperiod. At 144 h, several genes related to thyroid hormones that are essential for neurodevelopment, including corticotropin releasing hormone b (crhb), iodothyronine deiodinase 3a (dio3a), thyroid-stimulating hormone receptor (tshr) and nkx2 homeobox1 (nkx 2.1), were up-regulated by 8:8 PFPiA at 5.79 μM. 8:8 PFPiA also significantly down-regulated a neurodevelopmental gene, elav like neuron-specific RNA binding protein (elavl3), at 1.34 and 5.79 μM; in addition, one oxidative stress gene was slightly but significantly up-regulated. Further, global DNA methylation was significantly decreased at higher treatment levels, identifying effects of 8:8 PFPiA on epigenetic regulation. However, promoter DNA methylation of selected genes (dio3, tshr, nkx2.1) were not statistically altered, though dio3 methylation showed a decreasing trend with 8:8 PFPiA exposure. Our results specifically advance an understanding of molecular toxicology of PFPiA and more broadly present an approach to define diverse responses during animal alternative assessments of PFASs.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139600DOI Listing
September 2020

Wastewater sources of per- and polyfluorinated alkyl substances (PFAS) and pharmaceuticals in four Canadian Arctic communities.

Sci Total Environ 2020 Mar 29;708:134494. Epub 2019 Nov 29.

Richardson College for the Environment, University of Manitoba, Winnipeg, MB, Canada; Department of Chemistry, The University of Winnipeg, Winnipeg, MB, Canada; Department of Environment and Geography, University of Manitoba, Winnipeg, MB, Canada; Escuela de Química, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica; School of Environment, Jinan University, Guangzhou 510632, China. Electronic address:

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.
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http://dx.doi.org/10.1016/j.scitotenv.2019.134494DOI Listing
March 2020

Field Evaluation and in Situ Stress Testing of the Organic-Diffusive Gradients in Thin-Films Passive Sampler.

Environ Sci Technol 2018 11 12;52(21):12573-12582. Epub 2018 Oct 12.

Department of Chemistry , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada.

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.
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http://dx.doi.org/10.1021/acs.est.8b03622DOI Listing
November 2018

The influence of pH on sampler uptake for an improved configuration of the organic-diffusive gradients in thin films passive sampler.

Anal Chim Acta 2018 Aug 10;1018:45-53. Epub 2018 Mar 10.

Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada; Department of Chemistry and Department of Environmental Studies and Sciences, Richardson College for the Environment, The University of Winnipeg, 515 Portage Ave., Winnipeg, Manitoba, R3B 2E9, Canada. Electronic address:

Recent literature has demonstrated the utility of the organic-diffusive gradients in thin films (o-DGT) device as an effective passive sampler for polar organics in aquatic environments. Here, a new configuration comprising a polyacrylamide diffusive gel and Sepra™ ZT sorbent was developed and calibrated under multiple pH conditions. Linear uptake (r > 0.9) was observed at pH ≈ 5 for a suite of 31 pharmaceuticals and pesticides over 25 days, suitable for typical passive sampler deployments. At pH ≈ 8.5, linear uptake (r > 0.9) was observed for many of the same compounds. Comparisons of the uptake rates between the two pH experiments generally agreed (14% average relative error), with only 6 compounds exhibiting marked reduction with pH (e.g. sulfonamide antibiotics). These discrepancies may be explained by changes in analyte-sorbent interaction (H-bonding) due to speciation changes at varying pH. Samplers performed well in field evaluations conducted in an impacted river system, showing close agreement with the previously validated agarose/HLB o-DGT configuration deployed simultaneously. This work illustrates that polyacrylamide diffusive gels are a more robust and resistant outer-membrane material compared to agarose used in earlier o-DGT configurations. Sepra™ ZT binding gels served as an effective binding resin, offering a cost effective and commercially available sorbent.
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http://dx.doi.org/10.1016/j.aca.2018.02.074DOI Listing
August 2018