Time filter

Source Type

Findlay, OH, United States

Schenck K.,U.S. Environmental Protection Agency | Rosenblum L.,CBandI Federal Services | Ramakrishnan B.,CBandI Federal Services | Carson J.,CBandI Federal Services LLC | And 2 more authors.
Environmental Sciences: Processes and Impacts | Year: 2015

Ten low-order streams draining headwater catchments within the East Fork Little Miami Watershed were evaluated throughout one year for the presence of six steroidal hormones, the antibiotic sulfamethoxazole, the antimicrobials triclosan and triclocarban, and the artificial sweetener sucralose. The wastewater management practices in the catchments included septic systems, sanitary sewers, a combination of both, and a parkland with no treatment systems. The concentrations and detection frequencies of sucralose showed a significant positive correlation with the septic density in each catchment. A similar relationship was found for sulfamethoxazole. Both sucralose and sulfamethoxazole are hydrophilic and unlikely to be removed effectively by sorption during septic treatment. The concentrations and detection frequencies of the antimicrobials were also positively correlated with septic density. The presence of the antimicrobials in the streams indicates that although they are hydrophobic, removal during septic treatment was incomplete. The target analytes that correlated with septic density were also detected in stream samples collected below a wastewater treatment plant located within the same watershed. The steroidal hormone estrone was the most frequently detected analyte at all sites. However, the estrone concentrations and detection frequencies did not correlate with the septic density due to multiple non-point sources. This journal is © The Royal Society of Chemistry 2015.

Kanitkar Y.H.,Michigan State University | Stedtfeld R.D.,Michigan State University | Steffan R.J.,CBandI Federal Services LLC | Hashsham S.A.,Michigan State University | Cupples A.M.,Michigan State University
Applied and Environmental Microbiology | Year: 2016

Real-time quantitative PCR (qPCR) protocols specific to the reductive dehalogenase (RDase) genes vcrA, bvcA, and tceA are commonly used to quantify Dehalococcoides spp. in groundwater from chlorinated solvent-contaminated sites. In this study, loopmediated isothermal amplification (LAMP) was developed as an alternative approach for the quantification of these genes. LAMP does not require a real-time thermal cycler (i.e., amplification is isothermal), allowing the method to be performed using less-expensive and potentially field-deployable detection devices. Six LAMP primers were designed for each of three RDase genes (vcrA, bvcA, and tceA) using Primer Explorer V4. The LAMP assays were compared to conventional qPCR approaches using plasmid standards, two commercially available bioaugmentation cultures, KB-1 and SDC-9 (both contain Dehalococcoides species). DNA was extracted over a growth cycle from KB-1 and SDC-9 cultures amended with trichloroethene and vinyl chloride, respectively. All three genes were quantified for KB-1, whereas only vcrA was quantified for SDC-9. A comparison of LAMP and qPCR using standard plasmids indicated that quantification results were similar over a large range of gene concentrations. In addition, the quantitative increase in gene concentrations over one growth cycle of KB-1 and SDC-9 using LAMP was comparable to that of qPCR. The developed LAMP assays for vcrA and tceA genes were validated by comparing quantification on the Gene-Z handheld platform and a real-time thermal cycler using DNA isolated from eight groundwater samples obtained from an SDC-9-bioaugmented site (Tulsa, OK). These assays will be particularly useful at sites subject to bioaugmentation with these two commonly used Dehalococcoides species-containing cultures. © 2016, American Society for Microbiology. All Rights Reserved.

Kertesz R.,U S WEST | Burkhardt J.,U S WEST | Panguluri S.,CBandI Federal Services LLC
World Environmental and Water Resources Congress 2014: Water Without Borders - Proceedings of the 2014 World Environmental and Water Resources Congress | Year: 2014

The authors have used the CANARY event detection software for the purposes of detecting and identifying system response to rainfall in a permeable pavement stormwater best management practice that is installed in an academic parking lot in Cincinnati, OH. The results show that the software, originally designed for water quality detection in drinking water systems, proved adept at identifying a change in both underdrain flow and subsurface moisture in response to precipitation. Flow was measured as level in a 1-inch Parshall flume. Moisture was measured using four transmission line oscillation water content reflectometers placed in the aggregate media beneath interlocking concrete pavers. Of 21 storms greater than 2.5 mm of precipitation, all 21 were detected using CANARY software when evaluating flow detection. Nineteen of the 21 were detected using CANARY software to process the moisture signals. Additional event detections were generated from sensor device failures and maintenance activity. © 2014 American Society of Civil Engineers.

Danko A.S.,University of Lisbon | Fontenete S.J.,University of Porto | De Aquino Leite D.,University of Porto | De Aquino Leite D.,Federal University of Grande Dourados | And 7 more authors.
Journal of Molecular Microbiology and Biotechnology | Year: 2014

Chlorinated solvents including tetrachloroethene (perchloroethene and trichloroethene), are widely used industrial solvents. Improper use and disposal of these chemicals has led to a widespread contamination. Anaerobic treatment technologies that utilize Dehalococcoides spp. can be an effective tool to remediate these contaminated sites. Therefore, the aim of this study was to develop, optimize and validate peptide nucleic acid (PNA) probes for the detection of Dehalococcoides spp. in both pure and mixed cultures. PNA probes were designed by adapting previously published DNA probes targeting the region of the point mutations described for discriminating between the Dehalococcoides spp. strain CBDB1 and strain 195 lineages. Different fixation, hybridization and washing procedures were tested. The results indicated that the PNA probes hybridized specifically and with a high sensitivity to their corresponding lineages, and that the PNA probes developed during this work can be used in a duplex assay to distinguish between strain CBDB1 and strain 195 lineages, even in complex mixed cultures. This work demonstrates the effectiveness of using PNA fluorescence in situ hybridization to distinguish between two metabolically and genetically distinct Dehalococcoides strains, and they can have strong implications in the monitoring and differentiation of Dehalococcoides populations in laboratory cultures and at contaminated sites. © 2014 S. Karger AG, Basel.

Silva R.G.,CBandI Federal Services LLC | Nadagouda M.N.,U.S. Environmental Protection Agency | Patterson C.L.,U.S. Environmental Protection Agency | Panguluri S.,CBandI Federal Services LLC | And 3 more authors.
Environmental Science: Nano | Year: 2014

Multiple polymorphs (anatase, brookite and rutile) of titanium dioxide nanoparticles (TiO2-NPs) with variable structures were quantified in environmental matrices via microwave-based hydrofluoric (HF) and nitric (HNO3) mixed acid digestion and muffle furnace (MF)-based potassium hydroxide (KOH) fusion. The environmental matrices included stream bed sediments, kaolinite and bentonite. The percentage of titanium (Ti) recovered from the mixed acid digestion was not statistically different from KOH fusion when anatase and brookite TiO2-NPs were blended in all three environmental matrices. However, the percentage of Ti recovery of rutile TiO2-polymorph from the samples digested using the mixed acid digestion method was significantly lower [23 (±5), 12 (±6), 11 (±0.6)] than those digested using KOH fusion method [74 (±4), 53 (±7), 75 (±2)]. The recovery percent values reported are for Ti in sediment, kaolinite, and bentonite matrices, respectively. Exposing the TiO2-NP spiked samples to elevated heat and pressure reduced the recovery of Ti from all three polymorphs via mixed acid digestion. In contrast, Ti recoveries from KOH fusion improved after heat and pressure treatment. A narrowing of the X-ray diffraction (XRD) peaks for anatase and brookite after heat and pressure treatment indicated an increase in the aggregation or particle interaction of the TiO2-NPs. The XRD peaks for rutile TiO2-NP polymorph was similar before and after heat and pressure treatment. In summary, regardless of the selected environmental matrix type, the mixed acid digestibility of TiO2-NPs is polymorph-dependent; whereas, the KOH-fusion digestibility is polymorph independent. Therefore, when analyzing environmental samples containing TiO2-NPs with unknown polymorphs, a KOH-fusion digestion method is recommended for yielding consistent results. © 2014 the Partner Organisations.

Discover hidden collaborations