Concentrations Of Contaminants Of Emerging Concern Research Articles

Occurrence, persistence, and removal of contaminants of emerging concern through drinking water treatment processes – A case study in South Africa

The presence of contaminants of emerging concern (CECs) in drinking water is a global issue of concern. Evidence galore of the potential impacts of CECs on human health, yet there are no concrete guidelines or regulatory oversight to effectively tackle CECs exposure from drinking water. As a result, CECs concentrations can be well-above the suggested thresholds, particularly in low and middle-income countries (LMICs) due to undeveloped or underdeveloped (waste)water treatment infrastructure and/or substandard treatment practices. Yet, CECs occurrence and particularly their persistence during drinking water treatment is not well-documented in such settings. For this reason, here, the occurrence of 19 CECs was monitored across the different treatment steps (coagulation, sedimentation, sand filtration, and chlorination) of a typical water treatment plant in South Africa using UPLC-MS/MS. The most dominant CEC was, by and large, efavirenz (1103.9 ± 743.1 ng/L in raw water) tracing back to antiretroviral treatment for the human immunodeficiency virus (HIV) and revealing unpleasant realities about the HIV epidemic crisis in Sub-Sahara Africa (Global South) and possible drug abuse for illicit drug (whoonga/nyaope) manufacturing. For the other examined CECs, their concentrations in drinking water were, from higher to lower score: 1,7 dimethylxanthine (403.3 ± 244.2 ng/L) ≥ emtricitabine (358.4 ± 250.8 ng/L) ≥ atrazine (227.0 ± 61.0 ng/L) ≥ caffeine (194.1 ± 216.5 ng/L) ≥ tramadol (189.5 ± 112.4 ng/L) ≥ carbamazepine (122.9 ± 24.5 ng/L) ≥ sulfamethoxazole (107.8 ± 55.1 ng/L) ≥ methaqualone (72.2 ± 20.5 ng/L) ≥ benzotriazole (61.2 ± 18.8 ng/L) ≥ trimethoprim (59.1 ± 30.4 ng/L) ≥ cetirizine (33.7 ± 19.6 ng/L) ≥ codeine (26.7 ± 57.2 ng/L) ≥ naproxen (25.7 ± 11.3 ng/L) ≥ venlafaxine (21.6 ± 16.3 ng/L) ≥ acetaminophen (17.7 ± 25.8 ng/L) ≥ benzoylecgonine (9.6 ± 5.1 ng/L) ≥ methamphetamine (8.6 ± 6.4 ng/L) ≥ diclofenac (5.2 ± 7.9 ng/L). The large standard deviations indicate the high temporal variations in CECs releases in freshwater. The silver lining is that in the final drinking water, CECs concentrations are greatly reduced, with percentage removals in the range of 9 % (diclofenac) to 75 % (efavirenz). Nonetheless, in LMICs tangible limits and regulatory frameworks for the effective removal of CECs from drinking water, along with more robust polishing techniques such as activated carbon treatment, are missing and should be introduced to avoid the worst effects of CECs exposure.

Contaminants of Emerging Concern in Minnesota Subsurface Sewage Treatment Systems

Highlights CEC are quantified in septic tank effluent, soil, and groundwater within septic systems. The success of septic system treatment of specific CEC is discussed. Treatment of CEC is compared between wastewater in septic systems and land-applied septage. Advanced treatment impact on CEC levels is analyzed. Abstract. Contaminants of Emerging Concern (CEC) are gaining attention as they continue to attract public awareness and more environmental and health consequences are recognized. This study showcases CEC concentrations within Minnesota’s Subsurface Sewage Treatment Systems (SSTS). The study identifies a broad range of CECs associated with subsurface sewage treatment at four sites. Three sites are Minnesota Department of Transportation rest area SSTS with high user inputs, and one site is a septage land application field that receives septage from residential and septic commercial tanks. The studied CEC include antibiotics, chronic disease prescriptions, veterinary medicine, stimulants, hormones, antihistamines, pain and fever relief prescriptions, and a plasticizer. CEC were quantified in the septage, septic tank effluent, advanced treatment effluent, soil, and shallow groundwater. The samples were analyzed via mass spectrometry coupled with light chromatography, revealing that CEC concentrations decrease as they move through the SSTS system. Septage had the highest concentrations of CEC, followed by septic tank effluent. Groundwater had the third highest concentrations, and soils had the lowest concentrations of CEC. CEC concentrations are being reduced through SSTS, but some persist in shallow groundwater. Keywords: Decentralized wastewater system, Groundwater, Pharmaceuticals, Septage, Septic system, Septic tank, Wastewater.

An ecotoxicologically relevant approach to water quality monitoring for contaminants of emerging concern

Contaminants of Emerging Concern (CECs) have been documented across the seven continents, including Antarctica, and are likely an impediment to the sustainable management of natural resources. Most studies to date have relied on sweeping chemistry surveys, reliant upon sophisticated instrumentation. This approach is expensive, relies on limited laboratory capacity, and generates results that are spatially and temporally constrained. Here we review existing approaches that can overcome these limitations by focusing on effects-based monitoring. Passive samplers can generate long-term records regarding the occurrence of CECs. As samples are concentrated, their analysis can be achieved using equipment that will be more common and less expensive. A second approach involves rapid test methods for single compounds, including test strips, ELISA assays, and mobile phone-based analytic tools. These can provide inexpensive CEC presence data for many field sites and can be used to stratify sampling and thereby reduce cost. Identifying the presence of a single compound can often shed light on the likely presence of entire groups of chemicals. Pairing these chemistry-derived approaches with geospatial modeling to predict CEC presence and concentrations across watersheds has already been applied in several large watersheds. Utilizing available ecotoxicological knowledge bases provides an opportunity to link modeled CEC occurrence and concentrations with likely adverse biological responses. Finally, confirmatory on-site exposure experiments can corroborate the presence or absence of biological effects hypothesized from the above chain of evidence to provide natural resource managers with information to make conservation decisions.

Robust calculus for biotransformation in wastewater generalised across thousands of chemicals and conditions

Environmental context Decades of research tried to understand the inherent complexity of biodegradation of contaminants. We describe calculus of biodegradation driven by bioavailability, redox, geometry and acclimation (adaptation) of microbiota. We tested predictions for thousands of contaminants across wastewater treatment plants, explaining up to 70% of the variance in observations. This competes with more intensive methods, and enables more efficient monitoring, experimentation and data interpretation. Rationale Release of harmful contaminants of emerging concern (CECs) in the environment prompts possible adverse toxicological effects. Increasing population, water use and process wastewater generation require more efficient removal of contaminants that allows for effluent discharge within environmental regulatory limits. Wastewater treatment plants (WWTPs) can remove hazardous contaminants, limiting unwanted release. Fine-tuning WWTP settings to fit the location, time, season, wastewater type, etc. may enhance removals to reduce CEC concentrations and toxic pressures. Methodology For this purpose, we need robust tools to calculate removal efficiencies. We studied influences of operational settings and CEC properties on their removal in WWTPs. For this purpose, we parameterised thermochemical properties of CECs: for their (1) speciation and acidification, (2) (re/im)mobilisation due to (de)sorption into solid/water, (3) redox-mediated biotransformation and (4) acclimation of biomass so to utilise metabolic pathways for biotransformation. By combining these parameters, we developed an energy-based framework for calculating biotransformation rates. Results We evaluated our calculus using removal efficiency (%) data for 373 measurements of 60 CECs in 14 different Dutch WWTPs and an additional 667 CECs in 49 WWTPs across the world. Our prediction precision, R2 ≈ 0.65 (P < 10−5), captures influences of wastewater characteristics (multiple measurements for each WWTP). It is higher than R2-values of modelling approaches currently available. Our model explains CEC removal with appreciative certainty. We identified outliers during evaluation. These outliers were attributed mostly to back-transformation and uncertainty in long-term background concentrations of contaminants, causing consequent acclimation of microbial consortia. Discussion Biodegradability and CEC-degrading biomass can be estimated from concentration and environmental residence time. Our framework and underlying parametrisations have a mechanistic basis, utilising simple WWTP operational information (CEC concentration, temperature, suspended solids concentration, oxygen demand, etc.). Thereby, our work has wide potential for implementation. Our approach can supplement current fate assessment for CECs for improved environmental risk assessments. We conclude by discussing the potential for removal enhancement.

Recent Advances on Electrochemical Sensors for Detection of Contaminants of Emerging Concern (CECs)

Recent Advances on Electrochemical Sensors for Detection of Contaminants of Emerging Concern (CECs)

Reconnaissance Survey of Organic Contaminants of Emerging Concern in the Kabul and Swat Rivers of Pakistan.

The Swat and Kabul rivers of northern Pakistan are within an important regional watershed that supports river-based livelihoods and is impacted by untreated effluent discharges and municipal solid waste. Evidence indicates that fish populations are decreasing in these rivers. One potential cause of poor aquatic health is pollution; therefore, we investigated the presence of contaminants of emerging concern (CECs) in the river systems. Water samples were collected in the Kabul River (n = 9) and Swat River (n = 10) during seasons of high (summer 2018) and low (winter 2019) river flow. Agrochemicals, pharmaceuticals, plasticizers, chemicals in personal care products, and hormones were quantified via liquid chromatography high-resolution mass spectrometry. In the Swat River, caffeine (18-8452 ng/L), N,N-diethyl-meta-toluamide (DEET; 16-56 ng/L), and plasticizers (13-7379 ng/L) were detected at all sites during both seasons, while butachlor (16-98 ng/L) was detected only during high flow. In the Kabul River, caffeine (12-2081 ng/L) and several plasticizers (91-722 ng/L) were detected at all sites during both seasons, while DEET (up to 97 ng/L) was detected only during high flow. During low flow, pharmaceuticals (analgesics and nonsteroidal anti-inflammatory drugs) were quantified in both rivers (up to 823 ng/L), with detection frequencies from 70% to 100% and 0% to 78% in the Swat and Kabul Rivers, respectively. Intermittent-use and natural seasonal processes (increased runoff and dilution from rainfall and snowmelt) yielded higher agrochemical concentrations and lower concentrations of continuous-use compounds (e.g., caffeine) during high flow. The present study provides the first insight into CEC concentrations in the Swat River, additional insight into the Kabul River stressors, and, overall, contaminant risks to aquatic life. Environ Toxicol Chem 2023;42:2599-2613. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Occurrence of contaminants of emerging concern and pesticides and relative risk assessment in Tunisian groundwater

Groundwater is an important source for drinking water supply, agricultural irrigation and industrial uses in the Middle East and North Africa region. Due to the growing need for groundwater use, groundwater quality studies on the presence of contaminants of emerging concern (CECs) and pesticides have gained attention. The Wadi El Bey is one of the most polluted areas in Tunisia. However, very limited data on CECs infiltration into aquifers has been described, in comparison to industrialized countries where groundwater contamination has been comprehensively addressed. To gain early insight into potential contamination, groundwater wells in northeast Tunisia, an area with high population density and intensive agricultural activity were sampled during two seasons and were analyzed with two high resolution mass spectrometry approaches: target and suspect screening. The latter was used for screening banned pesticides. A selection of 116 CECs of which 19 are transformation products (TPs) and 20 pesticides previously prioritized by suspect screening were screened in the groundwater samples. The results showed the presence of 69 CECs and 1 TP and 20 pesticides at concentrations per well, ranging between 43 and 7384 ng L−1 and 7.3 and 80 ng L−1, respectively. CECs concentrations in Tunisian groundwater do not differ from those in industrialized countries. WWTPs were considered the main source of pollution, where the main classes detected were analgesics, antihypertensives and artificial sweeteners and especially caffeine, salicylic acid and ibuprofen were found to be ubiquitous. Regarding pesticides, triazines herbicides and carbamates insecticides pose the highest concern due to their ubiquitous presence, high leachability potential for most of them and high toxicity. The environmental risk assessment (ERA) highlighted the high risk that caffeine, ibuprofen, and propoxur may pose to the environment, and consequently, to non-target organisms. This study provides occurrence and ERA analysis of CECs and pesticides in Tunisian groundwater.

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.

Review of the Integration of Drying and Thermal Treatment Processes for Energy Efficient Reduction of Contaminants and Beneficial Reuse of Wastewater Treatment Plant Biosolids

Biosolids have been traditionally used as a beneficial resource in the agricultural industry. However, contaminants of emerging concern (CECs) threaten their reuse due to concerns of toxicity, bioaccumulation, and increased regulations on acceptable CEC concentrations in biosolids. The thermal treatment of biosolids has the potential to destroy/mineralize these contaminants as well as transform the biosolids into valuable biochar. However, the thermal processing of biosolids is highly energy intensive due to the energy costs associated with drying biosolids to the required moisture content for thermal processing. This article performs a brief review of the drying of biosolids from a physical and theoretical viewpoint. It also provides an overview of pyrolysis and gasification. It explains the impact that moisture can have on both the degradation of CECs and the products that can be obtained through the thermal treatment of biosolids. Additionally, model-based, lab-based, and pilot-scale examples of integrated drying and thermal treatment processes are reviewed. Key challenges, such as the need for co-pyrolysis and co-gasification, as well as the impact of biosolids composition on energetic viability, are identified.

A review toward contaminants of emerging concern in Brazil: Occurrence, impact and their degradation by advanced oxidation process in aquatic matrices.

This work presents data regarding the occurrence and treatment of Contaminants of Emerging Concern (CECs) in Brazil in the past decade. The literature review (2011-2021) revealed the detection of 87 pharmaceutical drugs and personal care products, 58 pesticides, 8 hormones, 2 illicit drugs, caffeine and bisphenol A in distinct matrices (i.e.: wastewater, groundwater, sea water, rainwater, surface water, drinking water and hospital effluent). Concentrations of CECs varied from ng-μg L-1 depending on the location, compound and matrix. The inefficiency of conventional wastewater treatment methods on the removal of CECs and lack of basic sanitation in some regions in the country aggravates contamination of Brazilian aquatic environments and poses potential environmental and health risks. Advanced oxidation processes (AOPs) are pointed out as viable and efficient alternatives to degrade CECs and prevent environmental contamination. A total of 375 studies involving the use of AOPs in Brazilian aqueous matrices were published in the last decade. Fenton and photo-Fenton processes, photo-peroxidation, ozonation, electrochemical advanced oxidation and heterogeneous photocatalysis are some of the AOPs applied by Brazilian research groups. Although many works discuss the importance of applying these technologies for CECs removal in real treatment plants, most of these studies assess the treatment of distilled water or simulated effluent. Therefore, the conduction of studies applying AOPs in real matrices are critical to drive the implementation of these processes coupled to conventional water and wastewater treatment in real plants in order to prevent the contamination of environmental matrices by CECs in Brazil.

A miniaturized passive sampling-based workflow for monitoring chemicals of emerging concern in water

The miniaturization of a full workflow for identification and monitoring of contaminants of emerging concern (CECs) is presented. Firstly, successful development of a low-cost small 3D-printed passive sampler device (3D-PSD), based on a two-piece methacrylate housing that held up to five separate 9 mm disk sorbents, is discussed. Secondly, a highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method reduced the need for large scale in-laboratory apparatus, solvent, reagents and reference material quantities for in-laboratory passive sampler device (PSD) calibration and extraction. Using hydrophilic-lipophilic balanced sorbents, sampling rates (Rs) were determined after a low 50 ng L−1 exposure over seven days for 39 pesticides, pharmaceuticals, drug metabolites and illicit drugs over the range 0.3 to 12.3 mL day−1. The high sensitivity LC-MS/MS method enabled rapid analysis of river water using only 10 μL of directly injected sample filtrate to measure occurrence of 164 CECs and sources along 19 sites on the River Wandle, (London, UK). The new 3D-PSD was then field-tested over seven days at the site with the highest number and concentration of CECs, which was down-river from a wastewater treatment plant. Almost double the number of CECs were identified in 3D-PSD extracts across sites in comparison to water samples (80 versus 42 CECs, respectively). Time-weighted average CEC concentrations ranged from 8.2 to 845 ng L−1, which were generally comparable to measured concentrations in grab samples. Lastly, high resolution mass spectrometry-based suspect screening of 3D-PSD extracts enabled 113 additional compounds to be tentatively identified via library matching, many of which are currently or are under consideration for the EU Watch List. This miniaturized workflow represents a new, cost-effective, and more practically efficient means to perform passive sampling chemical monitoring at a large scale. SynopsisMiniaturized, low cost, multi-disk passive samplers enabled more efficient multi-residue chemical contaminant characterization, potentially for large-scale monitoring programs.

Bioanalytical and chemical-specific screening of contaminants of concern in three California (USA) watersheds

To broaden the scope of contaminants monitored in human-impacted riverine systems, water, sediment, and treated wastewater effluent were analyzed using receptor-based cell assays that provide an integrated response to chemicals based on their mode of biological activity. Samples were collected from three California (USA) watersheds with varying degrees of urbanization and discharge from municipal wastewater treatment plants (WWTPs). To complement cell assay results, samples were also analyzed for a suite of contaminants of emerging concern (CECs) using gas and liquid chromatography-mass spectrometry (GC- and LC-MS/MS). For most water and sediment samples, bioassay equivalent concentrations for estrogen and glucocorticoid receptor assays (ER- and GR-BEQs, respectively) were near or below reporting limits. Measured CEC concentrations compared to monitoring trigger values established by a science advisory panel indicated minimal to moderate concern in water but suggested that select pesticides (pyrethroids and fipronil) had accumulated to levels of greater concern in river sediments. Integrating robust, standardized bioanalytical tools such as the ER and GR assays utilized in this study into existing chemical-specific monitoring and assessment efforts will enhance future CEC monitoring efforts in impacted riverine systems and coastal watersheds.

Analytical method to monitor contaminants of emerging concern in water and soil samples from a non-conventional wastewater treatment system

Nonconventional wastewater treatments, such as vegetation filters (VFs), are propitious systems to attenuate contaminants of emerging concern (CECs) in small municipalities. The development of standardised multiresidue and multimatrix methods suitable for measuring a reliable number of CEC in environmental samples is crucial for monitoring infiltrating concentrations and for ensuring these systems’ treatment capacity. The objective of this study is to develop and validate an analytical method for the simultaneous determination of CECs, including transformation products (TPs), with diverse physico-chemical properties, in environmental samples. The optimised method is based on sample clean-up and preconcentration by solid-phase extraction (SPE), followed by liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS). The method is able to detect and quantify 40 target CECs, including pharmaceuticals of different classes (analgesics, antibiotics, antihypertensives, lipid regulators, anticonvulsants, antidepressants, antiarrhythmics, beta-blockers, amongst others), hormones and lifestyle products with good reproducibility (variations below 23%), in different water matrices, and 28 CECs, in soil samples. Acceptable recoveries (65–120%) were obtained for most of the CECs in all the matrices. However in the soil samples, as complexity required a prior extraction treatment, the recovery of some analytes was affected, which reduced the number of target CECs. The achieved methodological quantification limits (0.05–5 ng/L and 0.04–1.1 ng/g levels for the water and the soil matrices, respectively) were reasonably low for most CECs. The proposed method was successfully applied to monitor CECs in a VF. The CECs detected at higher concentrations are some of the world's most widely used products (e.g. acetaminophen or caffeine and its main TP, paraxanthine). The results showed an almost 70% reduction in CEC concentrations during infiltration. The groundwater data indicated that the VF treatment operation did not affect the underlying aquifer (Cmax found in GW <1 µg/L).

Fate of contaminants of emerging concern in the reclaimed wastewater-soil-plant continuum

Reclaimed wastewater irrigation, a common agricultural practice in water-scarce regions, chronically exposes the agricultural environment to a wide range of contaminants of emerging concern (CECs) including pharmaceuticals and personal care products. Here we provide new data and insights into the processes governing the translocation of CECs in the irrigation water-soil-plant continuum based on a comprehensive dataset from 445 commercial fields irrigated with reclaimed wastewater. We report on CEC exposures in irrigation water, soils, and edible produce (leafy greens, carrots, potatoes, bananas, tomatoes, avocados, and citrus fruits). Our data show that CEC concentrations in irrigation water and their physiochemical properties (mainly charge and lipophilicity) are the main factors governing their translocation and accumulation in the soil-plant continuum. CECs exhibiting the highest detection frequency in plants (lamotrigine, venlafaxine, and carbamazepine) showed a reduction in their leaf accumulation factor with increasing soil organic matter content. The higher soil organic matter likely reduced the available CEC concentration in the soil solution due to soil-CEC interactions, leading to reduced uptake. Interestingly, the concentration of carbamazepine in the leaves showed a saturation-like trend when plotted against its concentration in the soils. This probably resulted from steady-state conditions when uptake equals in-planta decomposition. Our data indicate that due to continuous reclaimed wastewater irrigation, the soil acts as a sink for CECs. CECs in the soil reservoir can be desorbed into the soil solution during the rainy season and be taken up by rain-fed crops.

Confined space synthesis of chromium–based metal–organic frameworks in activated carbon: Synergistic effect on the adsorption of contaminants of emerging concern from water

The steadfast presence of contaminants of emerging concern (CECs) in the environment calls for tailored remediation strategies. In this regard, Cr-based metal-organic frameworks (MOFs; MIL-100Cr and MIL-101Cr) were grown inside of activated carbon (AC) pores via confined synthesis for a superior adsorptive removal of those CECs from water. The composites CMOF-100Cr and CMOF-101Cr, as well as the apohost AC and pure MOFs, were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDAX), nitrogen adsorption–desorption, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy, and zeta potential measurements. XRD, SEM/EDAX, TGA, and pore size distribution data provided direct evidence of the successfully confined space syntheses of the hierarchical composites. Occupancy of the large voids of AC by the MOF was 100% and 43% for CMOF-100Cr and CMOF-101Cr, respectively. The adsorption capacity of the materials was evaluated in both single- and multi-component fashion at neutral pH and low CEC concentrations (μg L−1). The CECs were caffeine (CFN), carbamazepine (CBZ), clofibric acid (CA), naproxen (NPX), and metabolites 10,11-epoxycarbamazepine (Ep-CBZ), o-desmethylnaproxen (o-DMN), paraxanthine (PXN), and salicylic acid (SA). In general, the observed capacities for both single and multi-component adsorption of CECs increased as follows MIL-100Cr < < MIL-101Cr < CMOF-101Cr < AC < < CMOF-100Cr. Compared to the composite containing MIL-100Fe (i.e., CMOF-100Fe) previously developed by our group, the substitution of the metal node by Cr3+ produced significant enhancements in CEC uptake capacities. The affinity of CMOF-100Cr toward CECs increases as follow: SA < CA< o-DMN < NPX < PXN < CFN < Ep-CBZ < CBZ. Environmental significanceThe persistence of contaminants of emerging concern (CECs) in water mandates the development of tailored remediation strategies. To be suitable, these must consider efficacy and avoid undesired byproducts. An attempt to individually grow two chromium-based nanoporous metal-organic frameworks, each possessing particular linkers, within the pores of an activated carbon via confined space synthesis has proven to be effective in the adsorptive removal of a set of CECs that included metabolites. Furthermore, the adsorption was conducted in both single- and multi-component fashion to gain insight into the CECs competitive nature during uptake. The hierarchical composite adsorbents exhibited superior uptake capacity because of the synergistic combination of hydrophobicity and specific interactions between the metal node and the CECs, while multiple adsorption cycles were possible via thermal regeneration.

Contaminants of Emerging Concern in the Lower Volta River, Ghana, West Africa: The Agriculture, Aquaculture, and Urban Development Nexus.

Contaminants of emerging concern (CECs) are ubiquitous in aquatic environments across all continents and are relatively well known in the developed world. However, few studies have investigated their presence and biological effects in low- and middle-income countries. We provide a survey of CEC presence in the Volta River, Ghana, and examine the microbial consequences of anthropogenic activities along this economically and ecologically important African river. Water and sediment samples were taken by boat or from shore at 14 sites spanning 118 km of river course from the Volta estuary to the Akosombo dam. Sample extracts were prepared for targeted analysis of antimicrobial CECs, N,N-diethyl-meta-toluamide, and per- and polyfluoroalkyl substances (PFAS; water only). Concurrent samples were extracted to characterize the microbial community and antibiotic-resistant genes (ARGs). Antibiotics and PFAS (PFAS, 2-20 ng/L) were found in all water samples; however, their concentrations were usually in the low nanograms per liter range and lower than reported for other African, European, and North American studies. N,N-Diethyl-meta-toluamide was present in all samples. The number of different genes detected (between one and 10) and total ARG concentrations varied in both water (9.1 × 10-6 to 8.2 × 10-3 ) and sediment (2.2 × 10-4 to 5.3 × 10-2 ), with increases in gene variety at sites linked to urban development, sand mining, agriculture, and shellfish processing. Total ARG concentration spikes in sediment samples were associated with agriculture. No correlations between water quality parameters, CEC presence, and/or ARGs were noted. The presence of CECs in the lower Volta River highlights their global reach. The overall low concentrations of CECs detected is encouraging and, coupled with mitigation measures, can stymie future CEC pollution in the Volta River.Environ Toxicol Chem 2022;41:369-381. © 2021 SETAC.

Assessing Occurrence and Biological Consequences of Contaminants of Emerging Concern on Oceanic Islands

Freshwater streams on oceanic islands serve critical ecological and economic functions. However, these are underrepresented in assessments of pollution from contaminants of emerging concern (CEC). Furthermore, freshwater streams and their endemic fauna often have characteristics that are distinct from those of continental streams and model species, calling extrapolations from studies of such systems into question for island streams. In the current study, we assessed the presence of CEC across three sampling events and five freshwater streams on the Island of Hawai’i. We also exposed juveniles of the native fish species Sicyopterus stimpsoni to a mixture of commonly co-occurring CEC for 96 h in static renewal experiments, testing for impacts of CEC in two ecologically relevant assays of functional performance. CEC from multiple sources were ubiquitous in Hawaiian streams, including human-use pharmaceuticals, agricultural herbicides, and industrial runoff. Concentrations of CEC were comparable to published studies from continental streams, exceeding total concentrations of 1000 ng/L for the eight quantified CEC in four samples, and approaching 2500 ng/L in one sample. Effects on exposed fish were subtle and limited to treatments with higher CEC concentrations but indicated potential impacts of CEC on locomotor performance. These results indicate that Hawaiian streams follow a global trend of widespread freshwater pollution by CEC that are accompanied by subtle effects on native fish species and highlight the need for the inclusion of endemic species and ecologically relevant assays when assessing the effects of contaminants in island habitats.

Contaminants of emerging concern (CECs) in Zea mays: Uptake, translocation and distribution tissue patterns over the time and its relation with physicochemical properties and plant transpiration rate

Passive uptake of contaminants of emerging concern (CECs) and its relationship with physicochemical properties, such as lipophilicity (LogKow), ionization behavior (pKa), distribution coefficient (LogDow) and transpiration rate are scarcely studied. In the current study, hydroponically grown corn (Zea mays) was exposed to carbamazepine (CBZ), fluoxetine (FLX), gemfibrozil (GBZ), triclosan (TRI) and atrazine (ATZ)) at environmentally relevant concentrations (20 μg/L each one). Plant tissue concentrations of CECs were determined several times over 21 days. Eighteen plants were used, nine exposed to the CECs and nine untreated. Whole plants were harvested at 7, 14 and 21 days and separated into roots, stem, leaf and male bud flower (only at 21 days). Hydroponic solution was maintained at pH 5.5 throughout the study. CECs concentrations in the exposure solution and tissues were determined by LC-MS/MS. ATZ metabolites desisopropylatrazine (DIA) and desethylatrazine (DEA) were determined by LC-DAD. In shoot tissues, CBZ, FLX and ATZ were detected, while TRI and GBZ were detected only in roots. Root concentrations were related with LogKow (R2ROOT = 0.415). Leaf and stem concentrations of CBZ, FLX and ATZ were linked with LogKow and strongly linked with pKa. Transpiration was related with CBZ and ATZ in shoot, but not related with FLX shoot levels. Neutral compounds such as CBZ (pKa = 13.94; 100% neutral) and ATZ (pKa = 1.6; 85% neutral) were taken up passively with transpiration. Root accumulation was related with CECs lipophilicity, while translocation and bioaccumulation in shoot were not only related with lipophilicity, but also with CECs ionization behavior and transpiration.

What's in the water? – Target and suspect screening of contaminants of emerging concern in raw water and drinking water from Europe and Asia

There is growing worry that drinking water can be affected by contaminants of emerging concern (CECs), potentially threatening human health. In this study, a wide range of CECs (n = 177), including pharmaceuticals, pesticides, perfluoroalkyl substances (PFASs) and other compounds, were analysed in raw water and in drinking water collected from drinking water treatment plants (DWTPs) in Europe and Asia (n = 13). The impact of human activities was reflected in large numbers of compounds detected (n = 115) and high variation in concentrations in the raw water (range 15-7995 ng L−1 for ∑177CECs). The variation was less pronounced in drinking water, with total concentration ranging from 35 to 919 ng L−1. Treatment efficiency was on average 65 ± 28%, with wide variation between different DWTPs. The DWTP with the highest ∑CEC concentrations in raw water had the most efficient treatment procedure (average treatment efficiency 89%), whereas the DWTP with the lowest ∑177CEC concentration in the raw water had the lowest average treatment efficiency (2.3%). Suspect screening was performed for 500 compounds ranked high as chemicals of concern for drinking water, using a prioritisation tool (SusTool). Overall, 208 features of interest were discovered and three were confirmed with reference standards. There was co-variation between removal efficiency in DWTPs for the target compounds and the suspected features detected using suspect screening, implying that removal of known contaminants can be used to predict overall removal of potential CECs for drinking water production. Our results can be of high value for DWTPs around the globe in their planning for future treatment strategies to meet the increasing concern about human exposure to unknown CECs present in their drinking water.

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.