Contaminants of emerging concern in urban stormwater: Spatiotemporal patterns and removal by iron-enhanced sand filters (IESFs)

Occurrence and potential hazard posed by pharmaceutically active compounds in coastal waters in Cape Town, South Africa

The occurrence of 58 pharmaceutically active compounds (PhACs) in surface water at 28 coastal and five river sites, and in two stormwater flows in Cape Town, South Africa, was investigated in winter and summer. After accounting for quality assurance and control data, 33 PhACs were considered in detail. In winter, 25 PhACs were found at one or more sites and 27 in summer. Salicylic acid was the most widespread PhAC in each season. At least one PhAC was found at each site in each survey. The largest number found at a site was 22 at Lifebox23 Beach in winter and 23 at Macassar Beach and in the Black and Diep Rivers in summer. These sites are strongly directly or indirectly affected by wastewater treatment plant discharges. The range in ΣPhAC concentrations was 41 ng L-1 to 9.3 μg L-1 in winter and 109 ng L-1 to 18.9 μg L-1 in summer. The hazard posed by PhACs was estimated using Predicted No Effect Concentrations (PNEC) from several sources. Hazard Quotients (HQs) for numerous PhACs were >1, and for several even >10, including azithromycin, cimetidine, clarithromycin, erythromycin, and ibuprofen. The highest hazards were at coastal sites strongly indirectly affected by wastewater treatment plant discharges. Azithromycin, trimethoprim, and sulfamethoxazole at some sites may have promoted antibiotic resistance in bacteria, while irbesartan at some sites might have posed a hazard to fish according to the fish plasma model. The concentrations of several PhACs at some coastal sites are higher than concentrations reported in estuarine, coastal, and marine waters in other parts of the world.

Occurrence of specific pollutants in a mixture of sewage and rainwater from an urbanized area

Urban runoff appears to be a pathway for transferring new emerging pollutants from land-based sources to the aquatic environment. This paper aimed to identify and describe the groups of pollutants present in rainwater surface runoff as well as their mixture with wastewater in the combined sewer system from urbanized catchments and to determine the correlations between these pollutants. Four leading groups of new emerging pollutants have been identified that may be present in rainwater and municipal wastewater mixtures. The samples were tested for microplastics, phthalic acid esters, pesticides, and polycyclic aromatic hydrocarbons as well as basic parameters. The pilot site was Słupsk (northwestern Poland). We conducted nine sampling campaigns at three points. The results of the present study revealed that (i) polycyclic aromatic hydrocarbons were not present in the tested samples; (ii) the selected organochlorine pesticides were detected during one campaign in the dry season and therefore were not of critical importance; (iii) out of the 11 analyzed phthalic acid esters, five selected substances released from commonly used plastic products were present; and (iv) the number of microplastics contained in the tested samples ranged from 1,400 to 14,036 pcs/L and even occurred during pure rainfall.

Review of trace organic chemicals in urban stormwater: Concentrations, distributions, risks, and drivers

Urban stormwater, increasingly seen as a potential water resource for cities and towns, contains various trace organic chemicals (TrOCs). This study, conducted through a comprehensive literature review of 116 publications, provides a detailed report on the occurrence, concentration distribution, health, and ecological risks of TrOCs, as well as the impact of land use and rainfall characteristics on their concentrations. The review uncovers a total of 629 TrOCs detected at least once in urban stormwater, including 228 pesticides, 132 pharmaceutical and personal care products (PPCPs), 29 polycyclic aromatic hydrocarbons (PAHs), 30 per- and polyfluorinated substances (PFAS), 28 flame retardants, 24 plasticizers, 22 polychlorinated biphenyls (PCBs), nine corrosion inhibitors, and 127 other industrial chemicals/intermediates/solvents. Concentration distributions were explored, with the best fit being log-normal distribution. Risk assessment highlighted 82 TrOCs with high ecological risk quotients (ERQ > 1.0) and three with potential health risk quotients (HQ > 1.0). Notably, 14 TrOCs (including six PAHs, five pesticides, three flame-retardants, and one plasticizer) out of 68 analyzed were significantly influenced by land-use type. Relatively weak relationships were observed between rainfall characteristics and pollutant concentrations, warranting further investigation. This study provides essential information about the occurrence and risks of TrOCs in urban stormwater, offering valuable insights for managing these emerging chemicals of concern.

A multi-marker assessment of sewage contamination in streams using human-associated indicator bacteria, human-specific viruses, and pharmaceuticals

Human sewage contaminates waterways, delivering excess nutrients, pathogens, chemicals, and other toxic contaminants. Contaminants and various sewage indicators are measured to monitor and assess water quality, but these analytes vary in their representation of sewage contamination and the inferences about water quality they support. We measured the occurrence and concentration of multiple microbiological (n = 21) and chemical (n = 106) markers at two urban stream locations in Milwaukee, Wisconsin, USA over two years. Five-day composite water samples (n = 98) were collected biweekly, and sewage influent samples (n = 25) were collected monthly at a Milwaukee, WI water reclamation facility. We found the vast majority of markers were not sensitive enough to detect sewage contamination. To compare analytes for monitoring applications, five consistently detected human sewage indicators were used to evaluate temporal patterns of sewage contamination, including microbiological (pepper mild mottle virus, human Bacteroides, human Lachnospiraceae) and chemical (acetaminophen, metformin) markers. The proportion of human sewage in each stream was estimated using the mean influent concentration from the water reclamation facility and the mean concentration of all stream samples for each sewage indicator marker. Estimates of instream sewage pollution varied by marker, differing by up to two orders of magnitude, but four of the five sewage markers characterized Underwood Creek (mean proportions of human sewage ranged 0.0025 % - 0.075 %) as less polluted than Menomonee River (proportions ranged 0.013 % - 0.14 %) by an order of magnitude more. Chemical markers correlated with each other and yielded higher estimates of sewage pollution than microbial markers, which exhibited greater temporal variability. Transport, attenuation, and degradation processes can influence chemical and microbial markers differently and cause variation in human sewage estimates. Given the range of potential human and ecological health effects of human sewage contamination, robust characterization of sewage contamination that uses multiple lines of evidence supports monitoring and research applications.

Investigation the existence and mechanism of Cu(II)-sulfamethoxazole co-pollution by road-deposited sediments in stormwater runoff

In recent years, the escalating attention on Pharmaceutical and Personal Care Products (PPCPs) and Heavy Metals in urban stormwater runoff highlights the critical role of Road-deposited sediments (RDS) as a significant carrier for pollutant occurrence and transport in runoff. However, existing research has overlooked the composite characteristics of PPCPs and Heavy Metals, hampering a holistic understanding of their transformation in diverse forms within runoff. This limitation impedes the exploration of their subsequent migration and conversion properties, thereby obstructing coordinated strategies for the control of co-pollution in runoff. This study focuses on the typical PPCP sulfamethoxazole (SMX) and heavy metal Cu(II) to analyze their occurrence characteristics in the Runoff-RDS system. Kinetics and isotherm studies reveal that RDS effectively accumulates SMX and Cu(II), with both exhibiting rapid association with RDS in the early stages of runoff. The accumulation of SMX and Cu(II) accounts for over 80 % and 70 % of the total accumulation within the first 240 min and 60 min, respectively. Moreover, as runoff pH values decrease, the initially synergistic effect between the co-pollutant transforms into an antagonistic effect. In the composite system, varying pH values from 2.0 to 6.0 lead to an increase in SMX accumulation from 4.01 mg/kg to 6.19 mg/kg and Cu(II) accumulation from 0.43 mg/g to 3.39 mg/g. Compared to the single system, the composite system capacity for SMX and Cu(II) increases by 0.04 mg/kg and 0.33 mg/g at pH 4.0. However, at pH 3.0, the composite system capacity for SMX and Cu(II) decreases by 0.21 mg/kg and 0.36 mg/g, respectively. Protonation/deprotonation of SMX under different pH conditions influences electrostatic repulsion/attraction between SMX and RDS. The mechanism of RDS accumulation of SMX involves Electron Donor-Acceptor (EDA) interaction, hydrogen bond interaction, and Lewis acid-base interaction. Cu(II) enrichment on RDS includes surface complexation reaction, electrostatic interaction, and surface precipitation. Complex formation enhances the accumulation of both SMX and Cu(II) on RDS in runoff. This study elucidates the co-occurrence characteristics and mechanisms of SMX and Cu(II) co-pollution in runoff systems. The findings contribute valuable insights to understanding the existence patterns and mechanisms of co-pollution, providing a reference for investigating the migration and fate of co-pollutant in runoff. Moreover, these insights could offer guidance for the development of effective strategies to mitigate co-pollution in rainwater.

Bioinspired stormwater control measure for the enhanced removal of truly dissolved polycyclic aromatic hydrocarbons and heavy metals from urban runoff

Stormwater harvesting (SWH) addresses the UN's Sustainable Development Goals (SDGs). Conventional stormwater control measures (SCMs) effectively remove particulate and colloidal contaminants from urban runoff; however, they fail to retain dissolved contaminants, particularly substances of concern like polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs), thereby hindering the SWH applicability. Here, inspired by protein folding in nature, we reported a novel biomimetic SCM for the efficient removal of dissolved PAHs and HMs from urban runoff. Lab-scale tests were conducted together with a more mechanistic investigation on how the contaminants were removed. By integrating hydrophobic organic chains with low-cost hydrophilic flocculant matrixes, our biomimetic flocculants achieved a 1.4-9.5 times removal of all detected dissolved PAHs and HMs, while enhancing the removal of a wide-spectrum of particulate and colloidal contaminants, compared to existing SCMs. Ecotoxicity, as indicated by newborn Daphnia magna as experimental organisms, was reduced from "acute toxicity" of the original runoff sample (toxic unit of ∼2.6) to "non-toxicity" (toxic unit < 0.4) of the treated water. The improved performance is attributed to the protein-folding-like features of the bioinspired flocculants providing: (i) stronger binding to PAHs (via hydrophobic association) and HMs (via coordination), and (ii) the ability of spontaneous aggregation. The bio-inspired approach in this work holds strong promise as an alternative or supplementary component in SCM systems, and is expected to contribute to sustainable water management practices in relation to SDGs.

Waterborne Tebuconazole Exposure Induces Male-Biased Sex Differentiation in Zebrafish (Danio rerio) Larvae via Aromatase Inhibition

Tebuconazole is a widely used fungicide for various crops that targets sterol 14-α-demethylase (CYP51) in fungi. However, attention has shifted to aromatase (CYP19) due to limited research indicating its reproductive impact on aquatic organisms. Herein, zebrafish were exposed to 0.5 mg/L tebuconazole at different developmental stages. The proportion of males increased significantly after long-term exposure during the sex differentiation phase (0-60, 5-60, and 19-60 days postfertilization (dpf)). Testosterone levels increased and 17β-estradiol and cyp19a1a expression levels decreased during the 5-60 dpf exposure, while the sex ratio was equally distributed on coexposure with 50 ng/L 17β-estradiol. Chemically activated luciferase gene expression bioassays determined that the male-biased sex differentiation was not caused by tebuconazole directly binding to sex hormone receptors. Protein expression and phosphorylation levels were specifically altered in the vascular endothelial growth factor signaling pathway despite excluding the possibility of tebuconazole directly interacting with kinases. Aromatase was selected for potential target analysis. Molecular docking and aromatase activity assays demonstrated the interactions between tebuconazole and aromatase, highlighting that tebuconazole poses a threat to fish populations by inducing a gender imbalance.

Evaluation of contaminants of emerging concern attenuation through a vegetation filter managed using different operating conditions

In wastewater treatment using Vegetation Filters (VFs), natural processes reduce contaminants present in water although some of them can reach the environment. In this study, 39 contaminants of emerging concern (CECs) are evaluated in a pilot VF under different operating conditions during almost four years. The use of woodchip amendments and the change from surface irrigation through furrows to drip irrigation (and from weekly to daily water application) provide CEC concentration reductions in the water infiltrating through the vadose zone. Biodegradation is the main process taking place and has been favoured mainly by woodchip soil amendments and the increased residence. Median attenuation percentages of the CECs most frequently detected with highest concentrations in applied wastewater vary between 52% and 100% at the end of the study (at 45 cm depth). Among targeted CECs, caffeine, and its transformation product paraxanthine are the most attenuated. Flecainide and venlafaxine show a persistent behaviour. However, their leaching concentrations are very low (< 31 ng/L). Concerning the underlying aquifer, the groundwater quality in terms of CEC concentrations is conditioned by the surrounding area rather than the operation of the VF. Levels in groundwater are always below those in wastewater and infiltrating water.

Predicting PFAS and Hydrophilic Trace Organic Contaminant Transport in Black Carbon-Amended Engineered Media Filters for Improved Stormwater Runoff Treatment

Improved stormwater treatment is needed to prevent toxic and mobile contaminant transport into receiving waters and allow beneficial use of stormwater runoff. In particular, safe capture of stormwater runoff to augment drinking water supplies is contingent upon removing dissolved trace organic contaminants (TrOCs) not captured by conventional stormwater control measures. This study builds upon a prior laboratory-based column study investigating biochar and regenerated activated carbon (RAC) amendment for removing hydrophilic trace organic contaminants (HiTrOCs) and poly- and perfluoroalkyl substances (PFASs) from stormwater runoff. A robust contaminant transport model framework incorporating time-dependent flow and influent concentration is developed and validated to predict HiTrOC and PFAS transport in biochar- and RAC-amended stormwater filters. Specifically, parameters fit using a sorption-retarded intraparticle pore diffusion transport model were validated using data further along the depth of the column and compared to equilibrium batch isotherms. The transport model and fitted parameters were then used to estimate the lifetime of a hypothetical stormwater filter in Seal Beach, CA, to be 35 ± 6 years for biochar- and 51 ± 17 years for RAC-amended filters, under ideal conditions with no filter clogging. This work offers insights on the kinetics of HiTrOC and PFAS transport within biochar and RAC filters and on the impact of filter design on contaminant removal performance and longevity.

Functional Group Properties and Position Drive Differences in Xenobiotic Plant Uptake Rates, but Metabolism Shares a Similar Pathway

Plant uptake of xenobiotic compounds is crucial for phytoremediation (including green stormwater infrastructure) and exposure potential during crop irrigation with recycled water. Experimentally determining the plant uptake for every relevant chemical is impractical; therefore, illuminating the role of specific functional groups on the uptake of trace organic contaminants is needed to enhance predictive power. We used benzimidazole derivatives to probe the impact of functional group electrostatic properties and position on plant uptake and metabolism using the hydroponic model plant Arabidopsis thaliana. The greatest plant uptake rates occurred with an electron-withdrawing functional group at the 2 position; however, uptake was still observed with an electron-donating group. An electron-donating group at the 1 position significantly slowed uptake for both benzimidazole- and benzotriazole-based molecules used in this study, indicating possible steric effects. For unsubstituted benzimidazole and benzotriazole structures, the additional heterocyclic nitrogen in benzotriazole increased plant uptake rates compared to benzimidazole. Analysis of quantitative structure-activity relationship parameters for the studied compounds implicates energy-related molecular descriptors as uptake drivers. Despite significantly varied uptake rates, compounds with different functional groups yielded shared metabolites, including an impact on endogenous glutathione production. Although the topic is complex and influenced by multiple factors in the field, this study provides insights into the impact of functional groups on plant uptake, with implications for environmental fate and consumer exposure.

Efficient Removal of Tetracycline and Bisphenol A from Water with a New Hybrid Clay/TiO2 Composite

New TiO₂ hybrid composites were prepared from kaolin clay, predried and carbonized biomass, and titanium tetraisopropoxide and explored for tetracycline (TET) and bisphenol A (BPA) removal from water. Overall, the removal rate is 84% for TET and 51% for BPA. The maximum adsorption capacities (q_m) are 30 and 23 mg/g for TET and BPA, respectively. These capacities are far greater than those obtained for unmodified TiO₂. Increasing the ionic strength of the solution does not change the adsorption capacity of the adsorbent. pH changes only slightly change BPA adsorption, while a pH > 7 significantly reduces the adsorption of TET on the material. The Brouers-Sotolongo fractal model best describes the kinetic data for both TET and BPA adsorption, predicting that the adsorption process occurs via a complex mechanism involving various forces of attraction. Temkin and Freundlich isotherms, which best fit the equilibrium adsorption data for TET and BPA, respectively, suggest that adsorption sites are heterogeneous in nature. Overall, the composite materials are much more effective for TET removal from aqueous solution than for BPA. This phenomenon is assigned to a difference in the TET/adsorbent interactions vs the BPA/adsorbent interactions: the decisive factor appears to be favorable electrostatic interactions for TET yielding a more effective TET removal.

Characterization of micropollutants in urban stormwater using high-resolution monitoring and machine learning

Urban rainfall events can lead to the runoff of pollutants, including industrial, pesticide, and pharmaceutical chemicals. Transporting micropollutants (MPs) into water systems can harm both human health and aquatic species. Therefore, it is necessary to investigate the dynamics of MPs during rainfall events. However, few studies have examined MPs during rainfall events due to the high analytical expenses and extensive spatiotemporal variability. Few studies have investigated the occurrence patterns of MPs and factors that influence their transport, such as rainfall duration, antecedent dry periods, and variations in streamflow. Moreover, while there have been many analyses of nutrients, suspended solids, and heavy metals during the first flush effect (FFE), studies on the transport of MPs during FFE are insufficient. This study aimed to identify the dynamics of MPs and FFE in an urban catchment, using high-resolution monitoring and machine learning methods. Hierarchical clustering analysis and partial least squares regression (PLSR) were implemented to estimate the similarity between each MP and identify the factors influencing their transport during rainfall events. Eleven dominant MPs comprised 75% of the total MP concentration and had a 100% detection frequency. During rainfall events, pesticides and pharmaceutical MPs showed a higher FFE than industrial MPs. Moreover, the initial 30% of the runoff volume contained 78.0% of pesticide and 50.1% of pharmaceutical substances for events W1 (July 5 to July 6, 2021) and W6 (August 31 to September 1, 2021), respectively. The PLSR model suggested that stormflow (m³/s) and the duration of antecedent dry hours (h) significantly influenced MP dynamics, yielding the variable importance on projection scores greater than 1.0. Hence, our findings indicate that MPs in urban waters should be managed by considering FFE.

Transformation Products of Tire Rubber Antioxidant 6PPD in Heterogeneous Gas-Phase Ozonation: Identification and Environmental Occurrence

6PPD, a tire rubber antioxidant, poses substantial ecological risks because it can form a highly toxic quinone transformation product (TP), 6PPD-quinone (6PPDQ), during exposure to gas-phase ozone. Important data gaps exist regarding the structures, reaction mechanisms, and environmental occurrence of TPs from 6PPD ozonation. To address these data gaps, gas-phase ozonation of 6PPD was conducted over 24-168 h and ozonation TPs were characterized using high-resolution mass spectrometry. The probable structures were proposed for 23 TPs with 5 subsequently standard-verified. Consistent with prior findings, 6PPDQ (C18H22N2O2) was one of the major TPs in 6PPD ozonation (∼1 to 19% yield). Notably, 6PPDQ was not observed during ozonation of 6QDI (N-(1,3-dimethylbutyl)-N'-phenyl-p-quinonediimine), indicating that 6PPDQ formation does not proceed through 6QDI or associated 6QDI TPs. Other major 6PPD TPs included multiple C18H22N2O and C18H22N2O2 isomers, with presumptive N-oxide, N,N'-dioxide, and orthoquinone structures. Standard-verified TPs were quantified in roadway-impacted environmental samples, with total concentrations of 130 ± 3.2 μg/g in methanol extracts of tire tread wear particles (TWPs), 34 ± 4 μg/g-TWP in aqueous TWP leachates, 2700 ± 1500 ng/L in roadway runoff, and 1900 ± 1200 ng/L in roadway-impacted creeks. These data demonstrate that 6PPD TPs are likely an important and ubiquitous class of contaminants in roadway-impacted environments.

Iron-enhanced sand filters: Multi-year urban runoff (stormwater) quality performance

Untreated urban runoff (stormwater) is a major pathway for contaminants, e.g., nutrients and metals, to receiving waters. Where eutrophication occurs, dissolved phosphorus (DP) treatment is often necessary to protect receiving waters, yet few practical methods exist. Iron-enhanced sand filters (IESFs) have successfully treated DP in laboratory and limited field studies. Yet, multi-year-IESF studies to understand reportedly variable performance are unavailable. Herein, nine IESFs were sampled from 2015 to 2018 (528 samples; 70 rainfall-runoff events). Analysis focused on influent/effluent concentrations and removal efficiencies alongside design and catchment parameters. Overall, IESFs significantly removed most total and dissolved metal analytes. Generally, phosphorus removal efficiencies correlated positively with influent concentrations and IESF:catchment area ratios, demonstrating the importance of proper sizing and siting. For all paired influent-effluent samples, respective median total phosphorus, orthophosphate, and DP removal efficiencies were 33 %, 41 %, and 13 %, and respective median effluent concentrations were 120, 25, and 75 (μg/L); with two malfunctioning sites omitted, these respective concentrations were 92, 11, and 47, which better matched relevant goals and (indirectly applicable) standards. Nonetheless, phosphorus removal efficiency and effluent concentrations varied significantly across IESFs and events. Seasonality appeared influential, yet variable influent concentrations confounded spatiotemporal removal efficiency comparisons. Thus, compared to removal efficiencies, effluent concentrations may be better indicators of receiving water risk/benefit and of equal importance for water quality crediting. Although 122 influent-effluent pairs were analyzed, a greater sample size would allow multivariate hypothesis tests with additional predictors. Overall, in this multi-site-year study, most IESFs performed at (n = 5) or near (n = 2) phosphorus effluent concentration and less-so, removal efficiency benchmarks. This research provides new quantitative knowledge on long-term IESF performance for real-world conditions and goals. Research recommendations include multivariate dimension reduction studies and comprehensive, effective information transfer to improve IESF understanding and performance and address practitioner needs, e.g., for refined design, operation, and assessment guidance.

Contaminant Exposure and Transport from Three Potential Reuse Waters within a Single Watershed

Global demand for safe and sustainable water supplies necessitates a better understanding of contaminant exposures in potential reuse waters. In this study, we compared exposures and load contributions to surface water from the discharge of three reuse waters (wastewater effluent, urban stormwater, and agricultural runoff). Results document substantial and varying organic-chemical contribution to surface water from effluent discharges (e.g., disinfection byproducts [DBP], prescription pharmaceuticals, industrial/household chemicals), urban stormwater (e.g., polycyclic aromatic hydrocarbons, pesticides, nonprescription pharmaceuticals), and agricultural runoff (e.g., pesticides). Excluding DBPs, episodic storm-event organic concentrations and loads from urban stormwater were comparable to and often exceeded those of daily wastewater-effluent discharges. We also assessed if wastewater-effluent irrigation to corn resulted in measurable effects on organic-chemical concentrations in rain-induced agricultural runoff and harvested feedstock. Overall, the target-organic load of 491 g from wastewater-effluent irrigation to the study corn field during the 2019 growing season did not produce substantial dissolved organic-contaminant contributions in subsequent rain-induced runoff events. Out of the 140 detected organics in source wastewater-effluent irrigation, only imidacloprid and estrone had concentrations that resulted in observable differences between rain-induced agricultural runoff from the effluent-irrigated and nonirrigated corn fields. Analyses of pharmaceuticals and per-/polyfluoroalkyl substances in at-harvest corn-plant samples detected two prescription antibiotics, norfloxacin and ciprofloxacin, at concentrations of 36 and 70 ng/g, respectively, in effluent-irrigated corn-plant samples; no contaminants were detected in noneffluent irrigated corn-plant samples.

Degradation of bisphenol A: a contaminant of emerging concern, using catalytic ozonation by activated carbon impregnated nanocomposite-bimetallic catalyst

Rampant water pollution events and rising water demand caused by exponential population growth and depleting freshwater resources speak of an impending water crisis. The inability of conventional wastewater treatment systems to remove contaminants of emerging concern (CECs) such as bisphenol A (BPA) beckons for new and efficient technologies to remove them from wastewater and water sources. Advanced oxidation processes such as ozonation are primarily known for their capability to oxidize and degrade organic entities in water, but optimum mineralization levels were hard to achieve. In this study, we synthesized an activated carbon impregnated nanocomposite-bimetallic catalyst (AC/CeO₂/ZnO) and used it along with ozonation to remove BPA from water. The catalyst was characterized using BET, XRD, FESEM, Raman spectra, and DLS studies. Catalytic ozonation achieved TOC removal 25% higher than non-catalytic ozonation process. The degradation pathway of BPA was proposed using LC-MS/LC-Q-TOF studies that found six main aromatic degradation byproducts. Catalytic ozonation and non-catalytic ozonation followed similar degradation pathways. The formation of persistent aliphatic acidic byproducts in the treated sample made total organic carbon (TOC) removal above 61% difficult.

A decade of monitoring micropollutants in urban wet-weather flows: What did we learn?

Urban wet-weather discharges from combined sewer overflows (CSO) and stormwater outlets (SWO) are a potential pathway for micropollutants (trace contaminants) to surface waters, posing a threat to the environment and possible water reuse applications. Despite large efforts to monitor micropollutants in the last decade, the gained information is still limited and scattered. In a metastudy we performed a data-driven analysis of measurements collected at 77 sites (683 events, 297 detected micropollutants) over the last decade to investigate which micropollutants are most relevant in terms of 1) occurrence and 2) potential risk for the aquatic environment, 3) estimate the minimum number of data to be collected in monitoring studies to reliably obtain concentration estimates, and 4) provide recommendations for future monitoring campaigns. We highlight micropollutants to be prioritized due to their high occurrence and critical concentration levels compared to environmental quality standards. These top-listed micropollutants include contaminants from all chemical classes (pesticides, heavy metals, polycyclic aromatic hydrocarbons, personal care products, pharmaceuticals, and industrial and household chemicals). Analysis of over 30,000 event mean concentrations shows a large fraction of measurements (> 50%) were below the limit of quantification, stressing the need for reliable, standard monitoring procedures. High variability was observed among events and sites, with differences between micropollutant classes. The number of events required for a reliable estimate of site mean concentrations (error bandwidth of 1 around the "true" value) depends on the individual micropollutant. The median minimum number of events is 7 for CSO (2 to 31, 80%-interquantile) and 6 for SWO (1 to 25 events, 80%-interquantile). Our analysis indicates the minimum number of sites needed to assess global pollution levels and our data collection and analysis can be used to estimate the required number of sites for an urban catchment. Our data-driven analysis demonstrates how future wet-weather monitoring programs will be more effective if the consequences of high variability inherent in urban wet-weather discharges are considered.

Using the Daphnia magna Transcriptome to Distinguish Water Source: Wetland and Stormwater Case Studies

A major challenge in ecotoxicology is accurately and sufficiently measuring chemical exposures and biological effects given the presence of complex and dynamic contaminant mixtures in surface waters. It is impractical to quantify all chemicals in such matrices over space and time, and even if it were practical, concomitant biological effects would not be elucidated. Our study examined the performance of the Daphnia magna transcriptome to detect distinct responses across three water sources in Minnesota: laboratory (well) waters, wetland waters, and storm waters. Pyriproxyfen was included as a gene expression and male neonate production positive control to examine whether gene expression resulting from exposure to this well-studied juvenoid hormone analog can be detected in complex matrices. Laboratory-reared (<24 h) D. magna were exposed to a water source and/or pyriproxyfen for 16 days to monitor phenotypic changes or 96 h to examine gene expression responses using Illumina HiSeq 2500 (10 million reads per library, 50-bp paired end [2 × 50]). The results indicated that a unique gene expression profile was produced for each water source. At 119 ng/L pyriproxyfen (~25% effect concentration) for male neonate production, as expected, the Doublesex1 gene was up-regulated. In descending order, gene expression patterns were most discernable with respect to pyriproxyfen exposure status, season of stormwater sample collection, and wetland quality, as indicated by the index of biological integrity. However, the biological implications of the affected genes were not broadly clear given limited genome resources for invertebrates. Our study provides support for the utility of short-term whole-organism transcriptomic testing in D. magna to discern sample type, but highlights the need for further work on invertebrate genomics. Environ Toxicol Chem 2022;41:2107-2123. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Road runoff as a significant nonpoint source of parabens and their metabolites in urban rivers

Parabens are widely added to food, cosmetics, and medicines as preservatives and are typical contaminants of pharmaceuticals and personal care products (PPCPs). However, their fate and transport in urban watersheds remain largely unexplored. This study investigated the role of road runoff as a critical nonpoint source of parabens and their metabolites in urban rivers based on 73 multimedia (road runoff and dust in different urban land uses, wastewater, stormwater discharge and river water) samples collected from a highly urbanized drainage area. Seven parabens and five metabolites were detected in the road runoff, with mean concentrations of ∑parabens and ∑metabolites equal to 47.5 ng/L and 4710 ng/L, respectively. The concentrations in road runoff were comparable to those in treated wastewater and river water and showed a land use pattern of residential > industrial > commercial. A first flush effect of the contaminants was observed in a heavy rainfall event with an antecedent dry period. In general, the population-based and area-based emission intensities of ∑parabens and ∑metabolites in road runoff were one order of magnitude higher than those in wastewater effluent during the rainfall events. This study provides quantitative evidence that road runoff can be a major pollution source of parabens and their metabolites in rapidly growing cities during the wet season and calls for the integrated management of nonpoint sources to prevent urban river contamination by typical PPCPs.

Validation of a vulnerability index of exposure to chemicals of emerging concern in surface water and sediment of Great Lakes tributaries of the United States

Widespread occurrence of emerging contaminants in Great Lakes tributaries led to the development and publication of a vulnerability index (VI) to assess the potential exposure of aquatic communities to chemicals of emerging concern (CEC) in the Great Lakes basin. The robust nature of the VI was tested to evaluate the underlying statistical model and expand the spatial domain of the index. Data collected at 131 new sampling sites (Test 1) and published data from independent studies (Test 2) were used to test the model predictions. Test 1 water and sediment samples were analyzed for the same classes of CEC chemicals and compared to the predictions for the original VI. Concentrations and numbers of unique CECs detected in water and sediment samples were similar between the original data and the two test datasets, although CECs tended to have higher detection frequencies in the original dataset compared to the Test 1 and Test 2 datasets. For example, 69 CECs were detected in ≥30% of water samples in the original dataset compared with 17 CECs in the Test 1 data and 59 in the Test 2 data. Predicted vulnerability for test sites agreed with actual vulnerability 64% of the time for water and 71% of the time for sediment. Agreement percentage results were greater when individual sites were grouped by river, with 82% agreement between predictions and actual vulnerability for water and 78% agreement for sediment. For the entire dataset, the VI ranks correlated with an independent estimate of potential biological impact. Agreement percentage was the greatest for low or high vulnerability index values but highly variable for sites that are classified as having medium vulnerability. Despite the underlying variability, there is a significant correlation (R² = 0.26; p < 0.01) between the VI ranking of tributaries and the independent ranking of potential negative biological impact.

Tris(2-butoxyethyl) phosphate (TBEP): A flame retardant in solid waste display hepatotoxic and carcinogenic risks for humans

Recent reports have confirmed that tris(2-butoxyethyl) phosphate (TBEP), an organophosphorous flame retardants (OPFRs), profoundly detected in the dust from solid waste (SW), e-waste dumping sites, landfills, and wastewater treatment facilities. Herein, we evaluated the hepatotoxic and carcinogenic potential of TBEP in human liver cells (HepG2). HepG2 cells exhibited cytotoxicity after 3 days of exposure, especially at greater concentrations (100-400 μM). TBEP induced severe DNA damage and cell cycle disturbances that trigger apoptosis in HepG2. TBEP treated cells showed an elevated level of esterase, nitric oxide (NO), reactive oxygen species (ROS), and influx of Ca²⁺ in exposed cells. Thereby, causing oxidative stress and proliferation inhibition. TBEP exposed HepG2 cells exhibited dysfunction in mitochondrial membrane potential (ΔΨm). Immunofluorescence analysis demonstrated cytoplasmic and nucleolar localization of DNA damage (P53) and apoptotic (caspase 3 and 9) proteins in HepG2 grown in the presence of TBEP for 3 days. Within the cohort of 84 genes of cancer pathway, 10 genes were upregulated and 3 genes were downregulated. The transcriptomic and toxicological data categorically emphasize that TBEP is hepatotoxic, and act as a putative carcinogenic agent. Thereby, direct or indirect ingestion of TBEP containing dusts by workers involved in handling and disposal of SW, as well as residents living nearby the disposal areas are prone to its adverse health risks.

A look down the drain: Identification of dissolved and particle bound organic pollutants in urban runoff waters and sediments

Urban runoff contains a range of organic micropollutants which, if not removed during wastewater treatment, pose a risk to aquatic environments. These mixtures are complex and often site-specific. Street drains provide an ideal sampling point given they collect the runoff from local and defined catchments. In this study, runoff was collected and sampled in five street drains located in a medium sized town in Germany. A specially constructed trap was used to collect the particulate and total water fractions of the runoff. In addition, passive samplers were deployed to determine the freely dissolved concentrations of selected compounds in the runoff. In sum, 187 polar organic micropollutants could be quantified using LC-HRMS. Thirty of these could only be detected by the use of passive samplers. Traffic derived pollutants such as corrosion inhibitors, rubber- and plastic additives, but also pollutants of industrial origin were strongly represented with sum median concentrations of 100 μg/kg dry weight (DW) in the sediment and 400 ng/L in the water fraction. Several of these substances are of concern due to their environmental persistence and mobility. Perfluorinated compounds and pesticides occurred at lower levels of several μg/kg DW sediment or ng/L water. A number of substances including pharmaceuticals, sweeteners and stimulants indicated domestic wastewater influences. Furthermore, a total of 62 parent and alkylated PAHs were quantified by GC-MS and contributed 30-70% to the sum concentrations of the micropollutants. Non-EPA PAHs dominated the carcinogenic PAH toxicity. The increased PAH alkylation indices (0.7-0.9) showed these primarily came from combustion sources. The runoff particles were additionally microscopically characterized, and correlations were found between the rubber particle counts and the PAH alkylation-index as well as the levels of 2-(methylthio)benzothiazole, a marker compound for tire leaching.

Household herbicide use as a source of simazine contamination in urban surface waters

Contamination of urban surface waters by herbicides is an increasing concern; however, sources of contamination are poorly understood, hindering the development of mitigation and regulatory strategies. Impervious surfaces, such as concrete in driveways and paths are considered an important facilitator for herbicide runoff to urban surface waters following applications by residential homeowners. This study assessed the transferability of a herbicide from concrete pavers treated with an off-the-shelf product, containing simazine as the active herbicide, marketed for residential homeowner application to impervious surfaces. Commercially available pavers were treated according to label directions and the effects of exposure time prior to irrigation, repeated irrigations, and dry time between irrigations on transferability of simazine to runoff were assessed. Simazine transferability was greatest when receiving an initial irrigation 1 h after application, with concentrations in runoff reduced by half when exposure times prior to the first irrigation were >2 days. Concentrations remained stable for repeated irrigations up to 320 days and exposures to outdoor conditions of 180 days prior to a first irrigation. Dry time between irrigations significantly influenced simazine transfer to runoff. Dry periods of 140 days resulted in approximately a 4-times increase in simazine transferability to runoff. These results suggest that herbicides used by homeowners, or any other users, on impervious surfaces are available to contaminate runoff for prolonged time periods following application at concentrations that may pose risks to aquatic life and for reuse of harvested runoff on parks and gardens. Regulators should consider the potential of hard surfaces to act as reservoirs for herbicides when developing policies and labelling products.

Occurrence and risk assessment of organophosphate esters and bisphenols in San Francisco Bay, California, USA

Organophosphate esters (OPEs) and bisphenols are two classes of industrial chemicals that are ubiquitously detected in environmental matrices due to high global production and widespread use, particularly in the manufacture of plastic products. In 2017, water samples collected throughout the highly urbanized San Francisco Bay were analyzed for 22 OPEs and 16 bisphenols using liquid chromatography-electrospray ionization-Q Trap-mass spectrometry. Fifteen of the 22 OPEs were detected, with highest median concentrations in the order TCPP (42 ng/L) > TPhP (9.5 ng/L) > TBOEP (7.6 ng/L) > TnBP (7.5 ng/L) > TEP (6.7 ng/L) > TDCIPP (6.2 ng/L). In contrast, only two of 16 bisphenols, BPA and BPS, were quantified, with concentrations ranging from <0.7-35 ng/L and <1-120 ng/L, respectively. BPA and a few OPEs (EHDPP and TEHP) were primarily present in the particulate phase, while BPS and all other observed OPEs were predominantly found in the dissolved phase. Pairwise correlation analysis revealed several strong, positive correlations among OPEs, and few weak, negative correlations between OPEs and BPA, suggesting differences between the two classes with respect to their sources, pathways, and/or fate in the environment. Concentrations of OPEs and bisphenols observed in this study were generally consistent with reported concentrations in other estuarine and marine settings globally. TDCIPP exceeded existing predicted no-effect concentrations (PNECs) at some sites, and six other compounds (TCrP, IDDPP, EHDPP, TPhP, TBOEP, and BPA) were observed at levels approaching individual compound PNECs (not considering mixture effects), indicating potential risks to Bay biota. These results emphasize the need to control releases of these contaminants in order to protect the ecosystem. Periodic monitoring can be used to maintain vigilance in the face of potential regrettable substitutions.

A pilot study to assess the influence of infiltrated stormwater on groundwater: Hydrology and trace organic contaminants

Underground infiltration basins (UIBs) mimic the natural hydrologic cycle by allowing stormwater to recharge local groundwater aquifers. However, little is known about the potential transport of organic contaminants to receiving groundwater. We conducted a pilot study in which we collected paired grab samples of stormwater runoff flowing into two UIBs (inflow) and shallow groundwater adjacent to the UIBs. Samples were collected coincident with three rain events and analyzed for volatile organic compounds, semi-volatile organic compounds, pharmaceuticals, and pesticides. Few contaminants were detected in groundwater, compared with inflow, and groundwater concentrations were typically an order of magnitude less. With one exception (trichloroethene), all groundwater concentrations were at least two orders of magnitude below available guidance or screening values. This short communication highlights information gaps in understanding the hydrologic connectivity between UIBs and receiving groundwater and potential consequent contaminant transport to the subsurface from varying climatic conditions. PRACTITIONER POINTS: Urban stormwater contains organic contaminants including pharmaceuticals, pesticides, and semi-volatile organic compounds that may be transported to groundwater via infiltration. In general, fewer contaminants were detected in groundwater and at lower concentrations, compared with urban stormwater runoff. Trace organic contaminant concentrations in groundwater were much lower than drinking water guidance/screening values.

Detection and Removal of Priority Substances and Emerging Pollutants from Stormwater: Case Study of the Kołobrzeska Collector, Gdańsk, Poland

Progressive urban development affects environmental balance and disrupts the hydrologic cycle, in which rainfall plays a significant role. Since rainwater is considered a valuable resource of the environment, many technical solutions are implemented that enable effective rainwater management. On the other hand, stormwater runoff from urban areas contains numerous (also toxic) substances, and therefore should be properly treated. In this study, a multistage constructed wetland (MCW) pilot installation was used to remove selected groups of priority substances and emerging pollutants from rainwater discharged from the urbanized catchment of the Kołobrzeska stormwater collector in Gdańsk, Poland. The obtained results show that rainwater runoff was characterized by a variable concentrations of heavy metals (Zn, Cd, Cu, Ni, Pb, Hg), polycyclic aromatic hydrocarbons (benzo(a)pyrene, benzo(b)fluoranthene, phenanthrene, fluoranthene and pyrene) and microplastics. Depending on the hydraulic load of the bed, the reduction efficiency for heavy metals ranged from 26.19 to 100%, and for microplastics from 77.16 to 100%, whereas for polycyclic aromatic hydrocarbons it was consistently high, and equaled 100%.

A review on plant-microbial interactions, functions, mechanisms and emerging trends in bioretention system to improve multi-contaminated stormwater treatment

Management and treatment of multi-polluted stormwater in bioretention system have gained significant attraction recently. Besides nutrients, recent source appointment studies found elevated levels of Potentially toxic metal(loid)s (PTMs) and contaminants of emerging concern (CECs) in stormwater that highlighted many limitations in conventional media adsorption-based pollutant removal bioretention strategies. The substantial new studies include biological treatment approaches to strengthen pollutants degradation and adsorption capacity of bioretention. The knowledge on characteristics of plants and their corresponding mechanisms in various functions, e.g., rainwater interception, retention, infiltration, media clogging prevention, evapotranspiration and phytoremediation, is scattered. The microorganisms' role in facilitating vegetation and media, plant-microorganism interactions and relative performance over different functions in bioretention is still unreviewed. To uncover the underneath, it was summarised plant and microbial studies and their functionality in hydrogeochemical cycles in the bioretention system in this review, contributing to finding their interconnections and developing a more efficient bioretention system. Additionally, source characteristics of stormwater and fate of associated pollutants in the environment, the potential of genetical engineered plants, algae and fungi in bioretention system as well as performance assessment of plants and microorganisms in non-bioretention studies to propose the possible solution of un-addressed problems in bioretention system have been put forward in this review. The present review can be used as an imperative reference to enlighten the advantages of adopting multidisciplinary approaches for the environment sustainability and pollution control.

Seasonal concentration variation and potential influencing factors of organophosphorus flame retardants in a wastewater treatment plant

Organophosphate flame retardants (OPFRs) in both of water and sludge phase of influent and effluent of the STP were investigated in Beijing of China in five seasons. Total OPFRs concentrations in water phase of influent in five seasons were between 600 and 838 ng/L, where total OPFRs concentration was the lowest in summer of 2018. In water phase of influent and effluent, two chlorinated OPFRs (TCEP and TCPP) were major. Alkyl OPFRs decreased the most in water phase from influent to effluent. In sludge phase, the OPFRs amounts in winter were the lowest. The main OPFRs in sludge phase were TEHP and EHDP, which can be explained by the two OPFRs properties (log K_ow and log K_oc). Higher the values of the log K_ow and log K_oc of OPFRs, more amounts in sludge phase. The mass flow of OPFRs in influent were analysed by Principal Component Analysis (PCA), indicating that the influent amounts of TCEP, TDCP, TCPP and DCP were main OPFRs in four seasons to influence the characteristics of influent. Compared to OPFRs reduction in some STPs in other countries, alkyl and aryl OPFRs reduction rates were higher than chlorinated OPFRs. TBEP, TEHP and TPHP can always be effectively removed in different seasons and different STPs. The analysis methods of Pearson correlation and linear correlation were processed to check the possible factors affecting OPFRs reduction in STP. OPFRs reduction was related to some STP working parameters. Significant correlation also was found between OPFRs properties and reduction.

Increased coverage and high confidence in suspect screening of emerging contaminants in global environmental samples

Suspect screening using liquid chromatography with high resolution mass spectrometry provides an opportunity for expanding the detection coverage of emerging contaminants in the environment. Screening workflows may suffer from high frequency of false positives or insufficient confidence in the identification of compounds; however, stringent criteria could lead to high false negatives. A workflow must have a balanced criteria, both selective and sensitive, to be able to identify real features without missing low abundant features traceable to analytes of interest. A highly selective (87%) and sensitive (97%) workflow was developed by characterizing the occurrence of contaminants in wastewater and surface water from Hong Kong, India, Philippines, Sweden, Switzerland, and the U.S. Sixty-eight contaminants were identified and confirmed with reference standards, including pharmaceuticals, pesticides, and industrial chemicals. The antimicrobials metronidazole, clindamycin, linezolid, and rifaximin were detected. Notably, antifungal compounds were detected in samples from six countries, with levels up to 1380 ng/L. Amoxicillin transformation products, penilloic acid (285-8047 ng/L) and penicilloic acid (107 ng/L), were confirmed for the first time with reference standards in wastewater samples from India, Sweden, and U.S. This workflow provides an efficient approach to broad-scale identification of emerging contaminants using publicly-available databases for suspect screening and prioritization.

Microbial pathogens and contaminants of emerging concern in groundwater at an urban subsurface stormwater infiltration site

Urban stormwater may contain a variety of pollutants, including viruses and other pathogens, and contaminants of emerging concern (pharmaceuticals, artificial sweeteners, and personal care products). In vulnerable geologic settings, the potential exists for these contaminants to reach underlying aquifers and contaminate drinking water wells. Viruses and other pathogens, as well as other contaminants of emerging concern, were measured in stormwater and groundwater at an urban site containing a stormwater cistern and related subsurface infiltration gallery, three shallow lysimeter wells, and a monitoring well. Five of 12 microbial targets were detected more than once across the eight rounds of sampling and at multiple sampling points, with human-specific Bacteroides detected most frequently. The microbial and chemical contaminants present in urban stormwater were much lower in the water table monitoring well than the vadose zone lysimeters. There may be numerous causes for these reductions, but they are most likely related to transit across fine-grained sediments that separate the water table from the vadose zone at this location. Precipitation amount prior to sample collection was significantly associated with microbial load. A significant relation between microbial load and chloride-bromide ratio was also observed. The reduction in number and concentrations of contaminants found in the monitoring well indicates that although geologically sensitive aquifers receiving urban stormwater effluent in the subsurface may be prone to contamination, those with a protective cap of fine-grained sediments are less vulnerable. These results can inform stormwater infiltration guidance relative to drinking water wells, with an emphasis on restricting infiltration near water supply wells finished in geologically sensitive aquifers to reduce public health risks.

A chemical prioritization process: Applications to contaminants of emerging concern in freshwater ecosystems (Phase I)

Contaminants of emerging concern (CECs), such as pharmaceuticals, personal care products, and hormones, are frequently found in aquatic ecosystems around the world. Information on sublethal effects from exposure to commonly detected concentrations of CECs is lacking and the limited availability of toxicity data makes it difficult to interpret the biological significance of occurrence data. However, the ability to evaluate the effects of CECs on aquatic ecosystems is growing in importance, as detection frequency increases. The goal of this study was to prioritize the chemical hazards of 117 CECs detected in subsistence species and freshwater ecosystems on the Grand Portage Indian Reservation and adjacent 1854 Ceded Territory in Minnesota, USA. To prioritize CECs for management actions, we adapted Minnesota Pollution Control Agency's Aquatic Toxicity Profiles framework, a tool for the rapid assessment of contaminants to cause adverse effects on aquatic life by incorporating chemical-specific information. This study aimed to 1) perform a rapid-screening assessment and prioritization of detected CECs based on their potential environmental hazard; 2) identify waterbodies in the study region that contain high priority CECs; and 3) inform future monitoring, assessment, and potential remediation in the study region. In water samples alone, 50 CECs were deemed high priority. Twenty-one CECs were high priority among sediment samples and seven CECs were high priority in fish samples. Azithromycin, DEET, diphenhydramine, fluoxetine, miconazole, and verapamil were high priority in all three media. Due to the presence of high priority CECs throughout the study region, we recommend future monitoring of particular CECs based on the prioritization method used here. We present an application of a chemical hazard prioritization process and identify areas where the framework may be adapted to meet the objectives of other management-related assessments.

Loading, transport, and treatment of emerging chemical and biological contaminants of concern in stormwater

Stormwater is a largely uncontrolled source of pollution in rural and urban environments across the United States. Concern regarding the growing diversity and abundance of pollutants in stormwater, as well as their impacts on water quality, has grown significantly over the past several decades. In addition to conventional contaminants like nutrients and heavy metals, stormwater is a well-documented source of many contaminants of emerging concern, which can be toxic to both aquatic and terrestrial organisms and remain a barrier to maintaining high quality water resources. Chemical pollutants like pharmaceuticals and personal care products, industrial pollutants such as per- and polyfluoroalkyl substances, and tire wear particles in stormwater are of great concern due to their toxic, genotoxic, mutagenic and carcinogenic properties. Emerging microbial contaminants such as pathogens and antibiotic resistance genes also represent significant threats to environmental water quality and human health. Knowledge regarding the transport, behavior, and the remediation capacity of these pollutants in runoff is key for addressing these pollutants in situ and minimizing ecosystem perturbations. To this end, this review paper will analyze current understanding of these contaminants in stormwater runoff in terms of their transport, behavior, and bioremediation potential.

Suspect and non-target screening of reuse water by large-volume injection liquid chromatography and quadrupole time-of-flight mass spectrometry

Eight samples were obtained to characterize the chemical loads in water recycled for reuse applications. The sources included stormwater, rooftop runoff, wastewater, mixed water, and drinking water as a comparison. The water was reused for irrigation, cleaning, toilet flushing, and cooling purposes. Large-volume injection (650 μL) high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry were employed to separate and detect features by suspect and non-target screening. The instrumental method had the advantage that no sample extractions were required prior to analysis. Two chromatographic methods were developed to separate positive- and negative-ionizing compounds and retention time models were developed for both. Retention time models provide an additional measure of confidence for probable and tentative identifications. The two models had predictive R²-which indicates how well the models predicts new observations-of 0.87. After data-reduction, the number of features detected in the samples ranged from 304 to 1513. Feature metrics such as the average response-per-feature provided a simple method to characterize similarities and differences between samples. Additionally, a statistical comparison was performed by principal component analysis. Of the 97 suspect-screening compounds, 20 were positively identified. Benzotriazole/benzothiazole-derivatives and per- and poly-fluoroalkyl substances were the most frequently detectedcompounds during suspect screening. Other compounds detected included pharmaceuticals, drug metabolites, and sucralose. Features were prioritized for non-target analysis based on in-house library matches, magnitude of response, and frequency of occurrence. Fifty-five unique compounds were positively identified via non-target analysis. The identified compounds included 17 pharmaceuticals, 17 pesticides, 13 industrial compounds, four personal-use compounds, and four biological compounds.

Removal of Pharmaceutical Residues from Water and Wastewater Using Dielectric Barrier Discharge Methods-A Review

Persistent pharmaceutical pollutants (PPPs) have been identified as potential endocrine disruptors that mimic growth hormones when consumed at nanogram per litre to microgram per litre concentrations. Their occurrence in potable water remains a great threat to human health. Different conventional technologies developed for their removal from wastewater have failed to achieve complete mineralisation. Advanced oxidation technologies such as dielectric barrier discharges (DBDs) based on free radical mechanisms have been identified to completely decompose PPPs. Due to the existence of pharmaceuticals as mixtures in wastewater and the recalcitrance of their degradation intermediate by-products, no single advanced oxidation technology has been able to eliminate pharmaceutical xenobiotics. This review paper provides an update on the sources, occurrence, and types of pharmaceuticals in wastewater by emphasising different DBD configurations previously and currently utilised for pharmaceuticals degradation under different experimental conditions. The performance of the DBD geometries was evaluated considering various factors including treatment time, initial concentration, half-life time, degradation efficiency and the energy yield (G50) required to degrade half of the pollutant concentration. The review showed that the efficacy of the DBD systems on the removal of pharmaceutical compounds depends not only on these parameters but also on the nature/type of the pollutant.

Application of an Effects-Based Monitoring Strategy to Assess the Impact of Contaminants on Fish Health in an Urbanized Watershed

Effects-based monitoring frameworks that combine the use of analytical chemistry with in vitro cell bioassays, as well as in vivo whole organism tests offer an integrative approach to broadly screen for chemical contaminants and link their presence with adverse effects on aquatic organisms. California (USA) is currently evaluating the use of such a framework to assess the impact of contaminants of emerging concern (CECs) on biota in urbanized rivers and other waterbodies. In the present study, the occurrence and effects of contaminants found in the Los Angeles River (Los Angeles County, CA, USA) were examined using analytical chemistry and in vitro and in vivo bioassays. Male fathead minnows were deployed in field-based exposure units and exposed to river water for 21 d. The 2 field sites (above Bull Creek [BLC] and below Glendale Water Reclamation Plant [GWR]) were selected based on their unique characteristics and different contaminant discharge sources. In addition, 2 control units (filtered city water and estrone-spiked water) were added to the experimental design. Chemical analyses revealed differences in abundance of CECs between the 2 field sites and the controls, with GWR having the highest number and concentrations of CECs and metals. Cell bioassays screening for estrogenic, glucocorticoid, progestin, and dioxin-like activities were near or below detection limits in all river water samples, indicating a low potential for endocrine-related toxicity and tissue damage. Cell bioassay results were corroborated by the in vivo analyses. Field-exposed fish exhibited no changes in plasma hormones (e.g., estradiol), vitellogenin, or gonad maturation, but gene biomarkers of chemical exposure (cytochrome p450 1A and metallothionein) were significantly elevated, confirming exposure of the fish to complex chemical mixtures. The results demonstrate the value of a tiered monitoring approach to assess the sublethal effects of chemical mixtures on aquatic life. Environ Toxicol Chem 2021;40:402-412. © 2020 SETAC.

Distribution and mass loads of xenoestrogens bisphenol a, 4-nonylphenol, and 4-tert-octylphenol in rainfall runoff from highly urbanized regions: A comparison with point sources of wastewater

This study pays a special attention to three phenolic endocrine disrupting compounds (EDCs), - bisphenol A (BPA), 4-nonylphenol (4-NP), and 4-tert-octylphenol (4-t-OP) - that are present in urban environments, resultant of several anthropogenic activities that can be also carried through rainfall runoff. We investigated the distributions of BPA, 4-NP, and 4-t-OP in Pearl River basin and estimated the mass loads in rainfall runoff, wastewater treatment plant (WWTP) effluents, and industrial wastewater from urbanized Huizhou and Dongguan regions. These three phenolic EDCs were detected frequently in tributaries and mainstream of Dongjiang River with the maximum 4-NP concentrations of 14,540 ng/L in surface waters and 3088 ng/g in sediments. BPA showed high concentrations in rainfall runoff samples with maximum concentrations of 5873 and 2397 ng/L in Huizhou and Dongguan regions, respectively, while concentrations for 4-NP and 4-t-OP were detected at tens to hundreds of nanograms per liter. Mass loads of phenolic EDCs from rainfall runoff were 3-62 times higher than those of WWTP effluents, suggesting rainfall runoff is an important source of phenolic EDCs into receiving waters. Sources and tributaries showed median to high estrogenic risks, while low to median risks were found in mainstream, implying the source control should be focused.

Emerging polar pollutants in groundwater: Potential impact of urban stormwater infiltration practices

The quality of groundwater (GW) resources is decreasing partly due to chemical contaminations from a wide range of activities, such as industrial and agricultural enterprises and changes in land-use. In urban areas, one potential major pathway of GW contamination is associated with urban water management practices based on stormwater runoff infiltration systems (SIS). Data on the performance of the upper layer of soil and the unsaturated zone of infiltration basins to limit the contamination of GW by hydrophilic compounds are lacking. With this aim, the impact of infiltration practices on GW contamination was assessed for 12 pesticides and 4 pharmaceuticals selected according to their ecotoxicological relevance and their likelihood of being present in urban stormwater and GW. For this purpose, 3 campaigns were conducted at 4 SIS during storm events. For each campaign, passive samplers based on the use of Empore™ disk were deployed in GW wells upstream and downstream of SIS, as well as in the stormwater runoff entering the infiltration basins. Upstream and downstream GW contaminations were compared to evaluate the potential effect of SIS on GW contamination and possible relationships with stormwater runoff composition were examined. Our results showed two interesting opposite trends: (i) carbendazim, diuron, fluopyram, imidacloprid and lamotrigine had concentrations significantly increasing in GW impacted by infiltration, indicating a contribution of SIS to GW contamination, (ii) atrazine, simazine and 2 transformation products exhibited concentrations significantly decreasing with infiltration due to a probable dilution of historic GW contaminants with infiltrated stormwater runoff. The other 7 contaminants showed no general trend. This study demonstrates that passive samplers deployed in GW wells enabled the capture of emerging polar pollutants present at very low concentrations and allowed the assessment of infiltration practices on GW quality. New data on GW and urban stormwater are provided for poorly studied hazardous compounds.

Growth inhibition and recovery patterns of common duckweed Lemna minor L. after repeated exposure to isoproturon

Aquatic non-targeted organisms are more likely to be exposed to herbicides in multiple pulse events then long continuous exposure. The potential of an organism to recover between exposures has an important role in the overall effects of the toxicant. Common duckweeds show high potential for recovery after a single exposure to isoproturon. To evaluate the growth patterns and recovery potential between multiple exposures, L. minor plants were exposed to isoproturon in three repetitive 7-day treatment cycles in three time-variable exposure scenarios with equivalent time-weighted average concentrations. The growth was significantly inhibited during each exposure phase with significant cumulative effects in every subsequent treatment cycle resulting in a cumulative decrease in biomass production. However, inhibitory effects were reversible upon transferring plants to a herbicide-free nutrient solution. These results indicate that L. minor plants have a high recovery potential even after multiple exposures to isoproturon. Observed cumulative decrease in biomass production, as well as the potential for fast and efficient recovery from repeated herbicide exposure, might affect the competitiveness of L. minor in surface water communities. The observations made during each exposure period, recovery patterns, and the resulting cumulative effects over time may contribute to further development, calibration and validation of mechanistic toxicokinetic/toxicodynamic models for simulating the effects of pesticides on aquatic plants populations in the laboratory and environmental conditions.

Occurrence of caffeine in the freshwater environment: Implications for ecopharmacovigilance

Owing to the substantial consumption of caffeinated food, beverages, and medicines worldwide, caffeine is considered the most representative pharmaceutically active compound (PhAC) pollutant based on its high abundance in the environment and its suitability as an indicator of the anthropogenic inputs of PhACs in water bodies. This review presents a worldwide analysis of 132 reports of caffeine residues in freshwater environments. The results indicated that more than 70% of the studies reported were from Asia and Europe, which have densely populated and industrially developed areas. However, caffeine pollution was also found to affect areas isolated from human influence, such as Antarctica. In addition, the maximum concentrations of caffeine in raw wastewater, treated wastewater, river, drinking water, groundwater, lake, catchment, reservoir, and rainwater samples were reported to be 3.60 mg/L, 55.5, 19.3, 3.39, 0.683, 174, 44.6, 4.87, and 5.40 μg/L, respectively. The seasonal variation in caffeine residues in the freshwater environment has been demonstrated. In addition, despite the fact that there was a small proportion of wastewater treatment plants in which the elimination rates of caffeine were below 60%, wastewater treatment is generally believed to have a high caffeine removal efficiency. From a pharmacy perspective, we proposed to adopt effective measures to minimize the environmental risks posed by PhACs, represented by caffeine, through a new concept known as ecopharmacovigilance (EPV). Some measures of EPV aimed at caffeine pollution have been advised, as follows: improving knowledge and perceptions about caffeine pollution among the public; listing caffeine as a high-priority PhAC pollutant, which should be targeted in EPV practices; promoting green design and production, rational consumption, and environmentally preferred disposal of caffeinated medicines, foods, and beverages; implementing intensive EPV measures in high-risk areas and during high-risk seasons; and integrating EPV into wastewater treatment programs.

Occurrence, mass loads and risks of bisphenol analogues in the Pearl River Delta region, South China: Urban rainfall runoff as a potential source for receiving rivers

Bisphenol (BP) analogues are widely used as industrial materials and various product additives and are inevitably released into environment. However, knowledge on the sources of different BPs, especially those from urban rainfall runoff to the receiving rivers is very limited. In this study, 15 BPs were determined in surface water, sediments, wastewater treatment plant (WWTP) and rainfall runoff samples in the Pearl River region, South China. Eleven BPs were detected in surface water and sediments of the Pearl Rivers. BPA was the dominant compound up to 2080 ng/L in surface and 1970 ng/g in sediments, followed by BPF, BPS, BPTMC and BPAF. In WWTPs, 10, 9 and 8 BPs were detected in influents, effluents and excess sludges, respectively, with total BPs (ΣBPs) concentrations in effluents still at thousands ng/L, suggesting incompletely removal of BPs. Five BPs were detected in urban rainfall runoff samples, with the ΣBPs concentrations up to 7740 ng/L. Mass loads of ΣBPs from the rainfall runoff (5800 kg/y) were almost equivalent to the source from WWTPs (7370 kg/y) in the region, implying that the urban rainfall runoff was a potential source for BPs into the receiving river. The calculated estrogenic activity contributed by BPs showed low to median risks in sources and receiving rivers. But BPs are always as mixtures with other potential endocrine disrupting chemicals (EDCs) which probably pose high estrogenic activity risks. Hence, effective measures should be taken to decrease the input of EDCs from sources to receiving rivers.

Occurrence of contaminants of emerging concern in aquatic ecosystems utilized by Minnesota tribal communities

Pharmaceuticals, personal care products, hormones, and other chemicals lacking water quality standards are frequently found in surface water. While evidence is growing that these contaminants of emerging concern (CECs) - those previously unknown, unrecognized, or unregulated - can affect the behavior and reproduction of fish and wildlife, little is known about the distribution of these chemicals in rural, tribal areas. Therefore, we surveyed the presence of CECs in water, sediment, and subsistence fish species across various waterbodies, categorized as undeveloped (i.e., no human development along shorelines), developed (i.e., human development along shorelines), and wastewater effluent-impacted (i.e., contain effluence from wastewater treatment plants), within the Grand Portage Indian Reservation and 1854 Ceded Territory in northeastern Minnesota, U.S.A. Overall, in 28 sites across three years (2016-2018), 117 of the 158 compounds tested were detected in at least one form of medium (i.e., water, sediment, or fish). CECs were detected most frequently at wastewater effluent-impacted sites, with up to 83 chemicals detected in one such lake, while as many as 17 were detected in an undeveloped lake. Although there was no statistically significant difference between the number of CECs present in developed versus undeveloped lakes, a range of 3-17 CECs were detected across these locations. Twenty-two CECs were detected in developed and undeveloped sites that were not detected in wastewater effluent-impacted sites. The detection of CECs in remote, undeveloped locations, where subsistence fish are harvested, raises scientific questions about the safety and security of subsistence foods for indigenous communities. Further investigation is warranted so that science-based solutions to reduce chemical risks to aquatic life and people can be developed locally and be informative for indigenous communities elsewhere.

Spatial Differences among Micropollutants in Sewer Overflows: A Multisite Analysis Using Passive Samplers

Untreated sewer overflows can contaminate receiving waters with micropollutants. Although concentrations of discharged micropollutants can be ecotoxicologically relevant, only limited data is available to assess occurrence and spatial differences among sewer overflow catchments. Therefore, we present an innovative type of data obtained with passive samplers at 20 combined sewer overflow sites (2-7 events per site; 95 events in total). The data sheds light on concentration ranges for 13 representative polar organic micropollutants and shows that micropollutants in both municipal wastewater and stormwater can be relevant sources of contaminants. We identify indicator micropollutants for further studies: benzotriazole (80% interquantile of time-weighted average concentration: 250-4800 ng/L), carbamazepine (33-910 ng/L), diclofenac (78-1000 ng/L), carbendazim (21-900 ng/L), diazinon (2.1-53 ng/L), diuron (22-1100 ng/L), mecoprop (98-5300 ng/L), metolachlor (6-230 ng/L), and terbutryn (29-810 ng/L). These concentration estimates are assumed to be on the safe side for comparison with environmental quality standards (EQS). A majority of sewer overflow sites (13 of 20) show discharge concentrations above acute EQS for at least one micropollutant and thus would have to rely on dilution by receiving waters to not exceed any EQS. The intersite variability among sewer overflows exceed the within-site variability. Hence, future monitoring studies should cover more sewer overflow sites. No correlation could be found with event durations, specific storage volume or land use data, thus showing the complexity of micropollutant occurrence and indicating that other factors led to the observed high spatial variability. In conclusion, our results clearly show the potential relevance of micropollutants in sewer overflows and the need to assess site-specific measures.

Hazardous waste treatment technologies

This is a review of the literature published in 2018 on topics related to hazardous waste management in water, soils, sediments, and air. The review covers treatment technologies applying physical, chemical, and biological principles for contaminated water, soils, sediments, and air. PRACTITIONER POINTS: The management of waters, wastewaters, and soils contaminated by various hazardous chemicals including inorganic (e.g., oxyanions, salts, and heavy metals), organic (e.g., halogenated, pharmaceuticals and personal care products, pesticides, and persistent organic chemicals) was reviewed according to the technology applied, namely, physical, chemical and biological methods. Physical methods for the management of hazardous wastes including adsorption, coagulation (conventional and electrochemical), sand filtration, electrosorption (or CDI), electrodialysis, electrokinetics, membrane (RO, NF, MF), photocatalysis, photoelectrochemical oxidation, sonochemical, non-thermal plasma, supercritical fluid, electrochemical oxidation, and electrochemical reduction processes were reviewed. Chemical methods including ozone-based, hydrogen peroxide-based, persulfate-based, Fenton and Fenton-like, and potassium permanganate processes for the management of hazardous were reviewed. Biological methods such as aerobic, anaerobic, bioreactor, constructed wetlands, soil bioremediation and biofilter processes for the management of hazardous wastes, in mode of consortium and pure culture were reviewed.