Pavement wear generates microplastics in stormwater runoff.

Tire and road wear particles are a major source of microplastics to urban stormwater. They are composed of hetero-aggregates of abraded tire and pavement particles that are difficult to distinguish. While tire wear is a known source of microplastics, little is known on the contribution of pavement wear.

Quantifying remediation of chlorinated volatile compounds by sulfidated nano zerovalent iron treatment using numerical modeling and CSIA.

Sulfidated nanoscale zerovalent iron (S-nZVI) has demonstrated promising reactivity and longevity for remediating chlorinated volatile compounds (cVOC) contaminants in laboratory tests. However, its effectiveness in field applications remains inadequately evaluated. This study provides the first quantitative evaluation of the long-term effectiveness of carboxymethyl cellulose-stabilized S-nZVI (CMC-S-nZVI) at a cVOC-contaminated field site.

Compound-Specific Carbon, Hydrogen, and Nitrogen Isotope Analysis of Nitro- and Amino-Substituted Chlorobenzenes in Complex Aqueous Matrices.

Compound-specific isotope analysis (CSIA) is an established tool to study the fate of legacy groundwater contaminants but is only emerging for nonconventional contaminants, e.g., nitro- and amino-substituted chlorobenzenes that are widely used as industrial feedstock and the target of this work.

Modeling multi-year phosphorus dynamics in a bioretention cell: Phosphorus partitioning, accumulation, and export.

Phosphorus (P) export from urban areas via stormwater runoff contributes to eutrophication of downstream aquatic ecosystems. Bioretention cells are a Low Impact Development (LID) technology promoted as a green solution to attenuate urban peak flow discharge, as well as the export of excess nutrients and other contaminants. Despite their rapidly growing implementation worldwide, a predictive understanding of the efficiency of bioretention cells in reducing urban P loadings remains limited.

Is In-Service Granular Activated Carbon Biologically Active? An Evaluation of Alternative Experimental Methods to Distinguish Adsorption and Biodegradation in GAC.

In-service granular activated carbon (GAC) may transform into biological activated carbon (BAC) and remove contaminants through both adsorption and biodegradation, but it is difficult to determine its biodegradative capacity. One approach to understand the GAC biodegradative capacity is to compare the performance between unsterilized and sterilized GAC, but the sterilization methods may not ensure effective microbial inhibition and may affect adsorption. This study identified the C-glucose respiration rate as the best metric to evaluate the effectiveness of three sterilization methods: sodium azide addition, autoclaving, and γ irradiation.

Harnessing plant-microbiome interactions for bioremediation across a freshwater urbanization gradient.

Urbanization impacts land, air, and water, creating environmental gradients between cities and rural areas. Urban stormwater delivers myriad co-occurring, understudied, and mostly unregulated contaminants to aquatic ecosystems, causing a pollution gradient. Recipient ecosystems host interacting species that can affect each others' growth and responses to these contaminants.

Implications of polar organic chemical integrative sampler for high membrane sorption and suitability of polyethersulfone as a single-phase sampler.

Polar organic chemical integrative sampler (POCIS) contains sorbent, which is typically enclosed between two polyethersulfones (PES) membranes. A significant PES uptake is reported for many contaminants, yet, aqueous concentration is mainly correlated with the sorbent uptake using first-order kinetics. Under high PES sorption, the first-order kinetics often provide erroneous sampling rate for the sorbent phase due to increased membrane resistance.

Evaluating perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) removal across granular activated carbon (GAC) filter-adsorbers in drinking water treatment plants.

Granular activated carbon (GAC) was harvested from six filter-adsorbers that are used for taste and odour control in three drinking water treatment plants in Ontario, Canada, and evaluated for the removal of perfluorooctanic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) using minicolumn tests under different operational conditions. Parallel column tests were conducted using unsterilized GAC and sterilized GAC to distinguish adsorption from potential biodegradation of PFOA and PFOS across the GAC. It was observed that the GAC could achieve approximately 20% to 55% of PFOA and PFOS removal even after a long period of GAC operation (e.

Stormwater Bioretention Cells Are Not an Effective Treatment for Persistent and Mobile Organic Compounds (PMOCs).

Bioretention cells are a stormwater management technology intended to reduce the quantity of water entering receiving bodies. They are also used to reduce contaminant releases, but their performance is unclear for hydrophilic persistent and mobile organic compounds (PMOCs). We developed a novel eight-compartment one-dimensional (1D) multimedia model of a bioretention cell ("Bioretention Blues") and applied it to a spike and recovery experiment conducted on a system near Toronto, Canada, involving PMOC benzotriazole and four organophosphate esters (OPEs).

Triclosan uptake and transformation by the green algae Euglena gracilis strain Z.

Triclosan is an antimicrobial chemical present in consumer products that is frequently detected in aquatic environments. In this research, we investigated the role of a common freshwater microalgae species, Euglena gracilis for triclosan uptake and transformation in open-water treatment wetlands. Lab-scale wetland bioreactors were created under various conditions of light (i.

Evaluating the relative adsorption and biodegradation of 2-methylisoborneol and geosmin across granular activated carbon filter-adsorbers.

This study investigated the relative contributions of adsorption vs. biodegradation towards 2-methylisoborneol (MIB) and geosmin removal in the granular activated carbon (GAC) harvested from six filter-adsorbers in three drinking water treatment plants in the Great Lakes region. Column tests using azide-treated (sterilized) and untreated GAC in parallel were used to isolate the two effects.

Automatic quantification and classification of microplastics in scanning electron micrographs via deep learning.

Microplastics quantification and classification are demanding jobs to monitor microplastic pollution and evaluate the potential health risks. In this paper, microplastics from daily supplies in diverse chemical compositions and shapes are imaged by scanning electron microscopy. It offers a greater depth and finer details of microplastics at a wider range of magnification than visible light microscopy or a digital camera, and permits further chemical composition analysis.

Understanding adsorption and biodegradation in granular activated carbon for drinking water treatment: A critical review.

Drinking water treatment plants use granular activated carbon (GAC) to adsorb and remove trace organics, but the GAC has a limited lifetime in terms of adsorptive capacity and needs to be replaced before it is exhausted. Biological degradation of target contaminants can also occur in GAC filters, which might allow the GAC to remain in service longer than expected. However, GAC biofiltration remains poorly understood and unpredictable.

Trace Organic Contaminant Transfer and Transformation in Bioretention Cells: A Field Tracer Test with Benzotriazole.

Bioretention cells can effectively infiltrate stormwater runoff and partly remove conventional water contaminants. A field tracer injection experiment in a conventionally designed bioretention cell was used to investigate the fate of benzotriazole, a model trace organic contaminant, during and between runoff events. Moderate (29%) benzotriazole load reductions were measured during the 6 h long injection experiment.

Carbon, hydrogen and nitrogen stable isotope fractionation allow characterizing the reaction mechanisms of 1H-benzotriazole aqueous phototransformation.

1H-benzotriazole is part of a larger family of benzotriazoles, which are widely used as lubricants, polymer stabilizers, corrosion inhibitors, and anti-icing fluid components. It is frequently detected in urban runoff, wastewater, and receiving aquatic environments. 1H-benzotriazole is typically resistant to biodegradation and hydrolysis, but can be transformed via direct photolysis and photoinduced mechanisms.

Bioretention cells remove microplastics from urban stormwater.

Microplastic pathways in the environment must be better understood to help select appropriate mitigation strategies. In this 2-year long field study, microplastics were characterized and quantified in urban stormwater runoff and through a bioretention cell, a type of low impact development infrastructure. Concentrations of microparticles ranged from below the detection limit to 704 microparticles/L and the dominant morphology found were fibers.

Optimization of a solid-phase microextraction technique for chloro‑ and nitro- substituted aromatic compounds using design of experiments.

A rapid and sensitive direct immersion solid-phase microextraction (SPME) technique for the analysis of seven chloro (Cl-) and nitro (NO-) substituted anilines, toluenes, and nitrobenzenes from small volume (1.5 mL) aqueous samples was optimized for gas chromatography using Design of Experiments (DoE). Screening of the SPME factors was performed by a fractional factorial DoE, and the optimization of influential factors was achieved with a central composite multi-response surface DoE.

Sulfidated nano zerovalent iron (S-nZVI) for in situ treatment of chlorinated solvents: A field study.

Sulfidated nano zerovalent iron (S-nZVI), stabilized with carboxymethyl cellulose (CMC), was successfully synthesized on site and injected into the subsurface at a site contaminated with a broad range of chlorinated volatile organic compounds (cVOCs). Transport of CMC-S-nZVI to the monitoring wells, both downgradient and upgradient, resulted in a significant decrease in concentrations of aqueous-phase cVOCs. Short-term (0-17 days) total boron and chloride measurements indicated dilution and displacement in these wells.

Resilience to multiple stressors in an aquatic plant and its microbiome.

Premise: Outcomes of species interactions, especially mutualisms, are notoriously dependent on environmental context, and environments are changing rapidly. Studies have investigated how mutualisms respond to or ameliorate anthropogenic environmental changes, but most have focused on nutrient pollution or climate change and tested stressors one at a time. Relatively little is known about how mutualisms may be altered by or buffer the effects of multiple chemical contaminants, which differ fundamentally from nutrient or climate stressors and are especially widespread in aquatic habitats.

Optimizing Constructed Wetlands for Safe Removal of Triclosan: A Box-Behnken Approach.

Traditional constructed wetland designs typically result in variable efficiencies for trace organic contaminant removal. In this work, we used a Box-Behnken experimental design for optimizing the conditions of pH, nitrate concentration, and dissolved organic carbon (DOC) concentration that would maximize the rate of triclosan phototransformation while minimizing the accumulation of toxic byproducts. Triclosan is a frequently detected and toxic antimicrobial agent present in many consumer and industrial products.

Mechanisms of pharmaceutical and personal care product removal in algae-based wastewater treatment systems.

The widespread distribution of pharmaceuticals and personal care products (PPCPs), particularly in the built environment, has led to increased concern about their effects on both human and ecosystem health. In this research, we investigated the role of algae species Scenedesmus obliquus and Chlorella vulgaris in governing PPCP transfer and transformation mechanisms in algae-containing environments. Lab-scale algal bioreactors were created under various conditions of light, water matrix, and sterilization method to isolate and elucidate reaction mechanisms affecting carbamazepine, ibuprofen, gemfibrozil, and triclosan.

Determination of in situ biodegradation rates via a novel high resolution isotopic approach in contaminated sediments.

A key challenge in conceptual models for contaminated sites is identification of the multiplicity of processes controlling contaminant concentrations and distribution as well as quantification of the rates at which such processes occur. Conventional protocol for calculating biodegradation rates can lead to overestimation by attributing concentration decreases to degradation alone. This study reports a novel approach of assessing in situ biodegradation rates of monochlorobenzene (MCB) and benzene in contaminated sediments.

Bioretention cells under cold climate conditions: Effects of freezing and thawing on water infiltration, soil structure, and nutrient removal.

Bioretention cells are a popular control strategy for stormwater volume and quality, but their efficiency for water infiltration and nutrient removal under cold climate conditions has been poorly studied. In this work, soil cores were collected from an active bioretention cell containing engineered soil material amended with a phosphate sorbent medium. The cores were used in laboratory column experiments conducted to obtain a detailed characterization of the soil's bioretention performance during six consecutive freeze-thaw cycles (FTCs, from -10 to +10 °C).