Publications by authors named "Rebecca A Trenholm"

Importance: Measuring drug use behaviors in individuals and across large communities presents substantial challenges, often complicated by socioeconomic and demographic variables.

Objectives: To detect spatial and temporal changes in community drug use by analyzing concentrations of analytes in influent wastewater and exploring their associations with area-based socioeconomic and sociodemographic metrics like the area deprivation index (ADI) and rural-urban commuting area (RUCA) codes.

Design, Setting, And Participants: This longitudinal, cross-sectional wastewater study was performed from May 2022 to April 2023 and included biweekly influent wastewater samples of 39 analytes from 8 sampling locations across 6 wastewater treatment plants in southern Nevada.

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Evaluating drug use within populations in the United States poses significant challenges due to various social, ethical, and legal constraints, often impeding the collection of accurate and timely data. Here, we aimed to overcome these barriers by conducting a comprehensive analysis of drug consumption trends and measuring their association with socioeconomic and demographic factors. From May 2022 to April 2023, we analyzed 208 wastewater samples from eight sampling locations across six wastewater treatment plants in Southern Nevada, covering a population of 2.

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The COVID-19 pandemic highlighted the value of wastewater surveillance in providing unbiased assessments of incidence/prevalence for infectious disease targets, ultimately leading to the development of local, state, and national programs across the United States. To address the growing epidemic of drug abuse, there have been calls to extend these programs to high risk substances (HRS) and metabolites, while leveraging the experience gained during the pandemic and from ongoing efforts in other countries. This study further advances the science of wastewater surveillance for HRS by (1) highlighting analytical and sewer transport considerations, (2) proposing sucralose normalization to adjust for varying human urine/fecal load and confounded population estimates (e.

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Unsheltered homelessness is rapidly becoming a critical issue in many cities worldwide. The worsening situation not only highlights the socioeconomic plight, but it also raises awareness of ancillary issues such as the potential implications for urban water quality. The objective of this study was to simultaneously leverage diverse source tracking tools to develop a chemical and microbial fingerprint describing the relative contribution of direct human inputs into Las Vegas' tributary washes.

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This study measured chlorine- and chloramine-reactive precursors using formation potential (FP) tests of nine U.S. Environmental Protection Agency (EPA) regulated and 57 unregulated disinfection byproducts (DBPs) in tertiary-filtered wastewater before and after pilot-scale granular activated carbon (GAC) adsorption.

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As potable reuse guidelines and regulations continue to develop, the presence of N-nitrosamines is a primary concern because of their associated health concerns. In this study, bench-, pilot-, and full-scale tests were conducted to focus on the occurrence and treatment of N-nitrosomorpholine (NMOR) in United States (U.S.

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The role of microbial communities in the degradation of trace organic contaminants in the environment is little understood. In this study, the biotransformation potential of 27 pharmaceuticals and endocrine-disrupting compounds was examined in parallel with a characterization of the native microbial community in water samples from four sites variously impacted by urban run-off and wastewater discharge in Lake Mead, Nevada and Arizona, USA. Samples included relatively pristine Colorado River water at the upper end of the lake, nearly pure tertiary-treated municipal wastewater entering via the Las Vegas Wash, and waters of mixed influence (Las Vegas Bay and Boulder Basin), which represented a gradient of treated wastewater effluent impact.

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UV/H2O2 processes can be applied to improve the quality of effluents from municipal wastewater treatment plants by attenuating trace organic contaminants (micropollutants). This study presents a kinetic model based on UV photolysis parameters, including UV absorption rate and quantum yield, and hydroxyl radical (·OH) oxidation parameters, including second-order rate constants for ·OH reactions and steady-state ·OH concentrations, that can be used to predict micropollutant abatement in wastewater. The UV/H2O2 kinetic model successfully predicted the abatement efficiencies of 16 target micropollutants in bench-scale UV and UV/H2O2 experiments in 10 secondary wastewater effluents.

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Nitrosamines are considered to pose greater health risks than currently regulated DBPs and are subsequently listed as a priority pollutant by the EPA, with potential for future regulation. Denver Water, as part of the EPA's Unregulated Contaminant Monitoring Rule 2 (UCMR2) monitoring campaign, found detectable levels of N-nitrosodimethylamine (NDMA) at all sites of maximum residency within the distribution system. To better understand the occurrence of nitrosamines and nitrosamine precursors, Denver Water undertook a comprehensive year-long monitoring campaign.

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Ozone-based treatment trains offer a sustainable option for potable reuse applications, but nitrosamine formation during ozonation poses a challenge for municipalities seeking to avoid reverse osmosis and high-dose ultraviolet (UV) irradiation. Six nitrosamines were monitored in full-scale and pilot-scale wastewater treatment trains. The primary focus was on eight treatment trains employing ozonation of secondary or tertiary wastewater effluents, but two treatment trains with chlorination or UV disinfection of tertiary wastewater effluent and another with full advanced treatment (i.

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The release of intracellular microcystin-LR (MC-LR), 2-methylisoborneol (MIB), and geosmin was investigated after the oxidation of three cyanobacteria (Microcystis aeruginosa (MA), Oscillatoria sp. (OSC), and Lyngbya sp. (LYN)).

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Although pharmaceuticals and personal care products (PPCPs) and endocrine disrupting compounds (EDCs) are largely unregulated, water resource recovery facilities are increasingly using advanced chemical/physical treatment technologies (e.g., advanced oxidation and reverse osmosis) to remove or destroy these trace organic contaminants (TOrCs).

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Ozonation is effective in improving the quality of municipal wastewater effluents by eliminating organic micropollutants. Nevertheless, ozone process design is still limited by (i) the large number of structurally diverse micropollutants and (ii) the varying quality of wastewater matrices (especially dissolved organic matter). These issues were addressed by grouping 16 micropollutants according to their ozone and hydroxyl radical ((•)OH) rate constants and normalizing the applied ozone dose to the dissolved organic carbon concentration (i.

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The performance of ozonation in wastewater depends on water quality and the ability to form hydroxyl radicals (·OH) to meet disinfection or contaminant transformation objectives. Since there are no on-line methods to assess ozone and ·OH exposure in wastewater, many agencies are now embracing indicator frameworks and surrogate monitoring for regulatory compliance. Two of the most promising surrogate parameters for ozone-based treatment of secondary and tertiary wastewater effluents are differential UV(254) absorbance (ΔUV(254)) and total fluorescence (ΔTF).

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The occurrence and concentrations of contaminants of emerging concern (CECs) were investigated in municipal effluents and in marine receiving water. Final effluent from four large publicly owned treatment works (POTWs) and seawater collected near the respective POTW outfall discharges and a reference station were collected quarterly over one year and analyzed for 56 CECs. Several CECs were detected in effluents; naproxen, gemfibrozil, atenolol, and tris(1-chloro-2-propyl)phosphate were the compounds most frequently found and with the highest concentrations (>1 µg/L).

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Diurnal variations in wastewater flows are common phenomena related to peak water use periods. However, few studies have examined high-resolution temporal variability in trace organic contaminant (TOrC) concentrations and loadings. Even fewer have assessed the impacts of a special event or holiday.

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In an effort to validate the use of ozone for contaminant oxidation and disinfection in water reclamation, extensive pilot testing was performed with ozone/H(2)O(2) and biological activated carbon (BAC) at the Reno-Stead Water Reclamation Facility in Reno, Nevada. Three sets of samples were collected over a five-month period of continuous operation, and these samples were analyzed for a suite of trace organic contaminants (TOrCs), total estrogenicity, and several microbial surrogates, including the bacteriophage MS2, total and fecal coliforms, and Bacillus spores. Based on the high degree of microbial inactivation and contaminant destruction, this treatment train appears to be a viable alternative to the standard indirect potable reuse (IPR) configuration (i.

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Proper collection and preservation techniques are necessary to ensure sample integrity and maintain the stability of analytes until analysis. Data from improperly collected and preserved samples could lead to faulty conclusions and misinterpretation of the occurrence and fate of the compounds being studied. Because contaminants of emerging concern, such as pharmaceuticals and personal care products (PPCPs) and steroids, generally occur in surface and drinking water at ng/L levels, these compounds in particular require such protocols to accurately assess their concentrations.

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This study evaluated a pilot-scale nonthermal plasma (NTP) advanced oxidation process (AOP) for the degradation of trace organic compounds such as pharmaceuticals and potential endocrine disrupting compounds (EDCs). The degradation of seven indicator compounds was monitored in tertiary-treated wastewater and spiked surface water to evaluate the effects of differing water qualities on process efficiency. The tests were also conducted in batch and single-pass modes to examine contaminant degradation rates and the remediation capabilities of the technology, respectively.

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A method using automated on-line solid phase extraction (SPE) directly coupled to liquid chromatography/tandem mass spectrometry (LC-MS/MS) has been developed for the analysis of six pharmaceuticals by isotope dilution. These selected pharmaceuticals were chosen as representative indicator compounds and were used to evaluate the performance of the on-line SPE method in four distinct water matrices. Method reporting limits (MRLs) ranged from 10 to 25 ng/L, based on a 1 mL extraction volume.

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The drinking water for more than 28 million people was screened for a diverse group of pharmaceuticals, potential endocrine disrupting compounds (EDCs), and other unregulated organic contaminants. Source water, finished drinking water, and distribution system (tap) water from 19 U.S.

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A method has been developed for the quantification of the formation of formaldehyde during the advanced oxidation treatment (AOT) of wastewater destined for reuse. This method uses solid-phase microextraction (SPME) with on-fiber derivatization followed by gas chromatography-mass spectrometry (GC-MS) analysis. Based on calculated method detection limits (MDL) and ambient background levels, the method reporting (MRL) limit for formaldehyde was set at 10 microg/L.

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A method has been developed for the determination of 24 household high production volume (HPV) chemicals in municipal wastewater systems using solid-phase extraction (SPE) and analyses using both gas chromatography and liquid chromatography, each with tandem mass spectrometry (GC-MS/MS and LC-MS/MS). Target compounds include pesticides, antioxidants, fragrances, plasticizers, preservatives and personal care products. Method reporting limits ranged from 0.

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Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) have been globally detected in impacted natural waters. The detection of trace quantities of EDCs and PPCPs in the environment is of great concern since some of these compounds have known physiological responses at low concentrations. EDCs can have a wide range of polarities, acidic and basic moieties, and exist in trace quantities, which often requires numerous complex extractions, large sample collection volumes, and multiple instrumental analyses.

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