Measured Environmental Concentrations Research Articles

Environmental risk of diclofenac in European groundwaters and implications for environmental quality standards

Groundwater harbours unique species adapted to perpetual darkness. Groundwater fauna plays a crucial role in global ecosystem services, but contamination poses a threat to this keystone ecosystem. Diclofenac is a common non-steroidal anti-inflammatory drug of particular concern, due to its presence in both surface and groundwater. We assess the environmental risk of diclofenac in European groundwaters using different scenarios, analyzing Measured Environmental Concentrations (MECs) of diclofenac and estimating the Predicted No Effect Concentration (PNECs) through two approaches: considering the sensitivity of the groundwater crustacean Proasellus lusitanicus (Isopoda: Asellidae), and using surface water species as proxies. Our results show that scenarios based on surrogate species predict that groundwater ecosystems are at risk due to diclofenac contamination. On the other hand, the MECs of diclofenac were consistently lower than the PNEC of P. lusitanicus, suggesting that the current MECs do not pose a significant threat to this groundwater-adapted species. However, risk scenarios differ considering the sensitivity of other groundwater species, emphasizing the importance of considering multiple species’ sensitivities in risk assessment. Therefore, we recommend establishing an environmental quality standard for diclofenac in groundwater at 5 ng/L, a value that accounts the need for precautionary measures to safeguard groundwater ecosystems, essential for preserving their unique biota and services.

Factors contributing to pesticide contamination in riverine systems: The role of wastewater and landscape sources

Wastewater treatment plant (WWTP) discharges can be a source of organic contaminants, including pesticides, to rivers. An integrated model was developed for the Potomac River watershed (PRW) to determine the amount of accumulated wastewater percentage of streamflow (ACCWW) and calculate predicted environmental concentrations (PECs) for 14 pesticides in non-tidal National Hydrography Dataset Plus Version 2.1 stream segments. Predicted environmental concentrations were compared to measured environmental concentrations (MECs) from 32 stream sites that represented a range of ACCWW and land use to evaluate model performance and to assess possible non-WWTP loading sources. Statistical agreement between PECs and MECs was strongest for insecticides, followed by fungicides and herbicides. Principal component analysis utilizing optical fluorescence and ancillary water quality data identified wastewater and urban runoff sources. Pesticides that indicated relatively larger sources from WWTPs included dinotefuran, fipronil, carbendazim, thiabendazole, and prometon whereas imidacloprid, azoxystrobin, propiconazole, tebuconazole, and diuron were more related to urban runoff. In addition, PECs generally comprised a low proportion of MECs, which indicates possible dominant loading sources beyond WWTP discharges. Cumulative potential toxicity was higher for sites with greater ACCWW and/or located in developed areas. Imidacloprid, fipronil, and carbendazim accounted for the largest portion of predicted potential toxicity across sites. The chronic aquatic life toxicity benchmarks for freshwater invertebrates were exceeded for 82 % of the imidacloprid detections (n = 28) and 47 % of the fipronil detections (n = 19). These results highlight the ecological implications of pesticide contamination from WWTP discharges and also the potential legacy effects from accumulated soil and groundwater sources. Pesticide management strategies that mitigate both current and historical impacts may improve the health of aquatic ecosystems.

Pesticides in wastewater treatment plant effluents in the Yeongsan River Basin, Korea: Occurrence and environmental risk assessment

Pesticides are among the main drivers posing risks to aquatic environments, with effluents from wastewater treatment plants (WWTPs) serving as a major source. This study aimed to identify the primary pesticides for which there was a risk of release into aquatic environments through WWTP effluents, thereby enabling more effective contamination management in public water bodies. In this study, monitoring, risk assessment, and risk-based prioritization of 87 pesticides in effluents from three WWTPs in the Yeongsan River Basin, Korea, were conducted. A total of 59 pesticides were detected at concentrations from 0.852 ng/L to 82.044 μg/L and exhibited variable patterns across different WWTP locations. An environmental risk assessment based on the risk quotient (RQ) of individual pesticides identified 13 substances implicated in significant ecotoxicological risks, as they exceeded RQ values of 1 at least once. An optimized risk (RQf)-based prioritization, considering the frequency of the measured environmental concentration (MEC) exceeding the predicted environmental concentration (PNEC), was conducted to identify pesticides that potentially posed risks and thus should be managed as a priority. Four pesticides had an RQf value >1; metribuzin exhibited the highest RQf value of 4.951, followed by 3-phenoxybenzoic acid, atrazin-2-hydroxy, and atrazine. Additionally, five pesticides (terbuthylazine, methabenzthiazuron, diuron, thiacloprid, and fipronil) and another four pesticides (propazine, imidacloprid, hexaconazole, and hexazione) had RQf values >0.1 and > 0.01, respectively. By calculating the contributions of individual pesticides to the RQf of these mixtures (RQf, mix) based on the concentration addition model, it was determined that >95 % of the sum of RQf, mix was driven by the top seven pesticides. These findings highlight the importance of prioritizing pesticides for effective management of contamination sources.

Biodegradation rate and build-up of plastics in soil: A theoretical approach

The ecological risk assessment of a product released into the environment is a complex process that takes into account both its ecotoxicity and the Predicted Environmental Concentration (PEC) in the environment. The latter depends on the use, transport, fate (i.e. persistence) of the product. This article describes a model to determine the Predicted Environmental Concentration (PEC) of a biodegradable mulch film taking into account its characteristics, the frequency of application of the mulch film, its degradation rate, and the density of the soil to which it is applied. The effect of temperature on biodegradation kinetics was also taken into account to estimate the biodegradation rate achievable at a given temperature based on data obtained in the laboratory under standard conditions. Using the same approach as for pharmacokinetics, the model can calculate the average mulch film concentration at steady state and the maximum concentration applied. The PEC values can be compared with the Predicted No-Effect Concentration (PNEC) derived from ecotoxicity studies to characterise the risk associated with use of mulch film. The model, if validated by comparison of the calculated PECs with the Measured Environmental Concentrations (MECs), determined by detection and quantification of biodegradable mulch film residues in soil, may provide a valuable tool for the ecological risk assessment of biodegradable mulch films.

Ecological impact of pharmaceutical pollutants and options of river health improvements - A risk analysis-based approach

Pharmaceuticals are one of the emerging pollutants (EPs) in river waters across the world. Due to their toxic effects on aquatic organisms, they have drawn the global attention of the scientific community concerned with river ecosystems. This paper reviews the existing occurrence data for various pharmaceutical pollutants (PPs) reported in river waters in some part of the world and their ecological impacts. Using algae, macroinvertebrates (MI), and fish as biotic indicator groups in water to reflect river health conditions, an attempt has been made to assess the ecological risk due to the presence of PPs in the water environment.After ascertaining the predicted no-effect concentration (PNEC) of PPs for selected groups of aquatic organisms, the risk quotient (RQ) is estimated based on their measured environmental concentration (MEC). When MEC > PNEC and RQ > 1 for any of the biotic indicator, ecologically it is ‘high risk’ condition. The determination of PNEC uses a minimum assessment factor (AF) of 10 due to uncertainty in data over the no observed effect level (NOEL) or lowest observed effect level (LOEL). Accordingly, MEC 10 times higher than PNEC, (RQ = 10) represents a threshold risk concentration (RCT) beyond which adverse effects may start showing observable manifestations. In the present study, a new classification system of ‘high risk’ conditions for RQ = 1–10 has been proposed, starting from ‘moderately high’ to ‘severely high’. For RQ > 10, the ecological condition of the river is considered ‘impaired’.For river health assessment, in the present study, the whole range of physico-chemical characteristics of river water quality has been divided into three groups based on their ease of measurement and frequency of monitoring. Dissolved oxygen related parameters (DORPs), nutrients (NTs), and EPs. PPs represent EPs in this study. A framework for calculating separate indicator group score (IGS) and the overall river health index (RHI) has been developed to predict indicator group condition (IGC) and river health condition (RHC), respectively. Color-coded hexagonal pictorial forms representing IGC and RHC provide a direct visible perception of the existing aquatic environment and a scientific basis for prioritization of corrective measures in terms of treatment technology selection for river health improvements.The analyses indicate that many rivers across the world are under ‘high risk’ conditions due to PPs having MEC > PNEC and RQ > 1. Up to RCT, (where RQ = 10), the ‘high risk’ condition varies from ‘moderately high’ to ‘severely high’. In many instances, RQ is found much more higher than 10, indicating that the ecological condition of river may be considered as ‘impaired’. Algae is the most frequently affected group of biotic indicators, followed by MI and fish.A review of treatment methods for selection of appropriate technology to reduce the pollution load, especially PPs from the wastewater streams has been summarized. It appears that constructed wetlands (CWs) are at present the most suitable nature-based solutions, particularly for the developing economies of the world, to reduce the concentrations of PPs within limits to minimize the ecological impacts of pharmaceutical compounds on biotic indicators and restore the river health condition. Some suggestive design guidelines for the CWs have also been presented to initiate the process.

Defining the data gap: What do we know about environmental exposure, hazards and risks of pharmaceuticals in the European aquatic environment?

Active pharmaceutical ingredients (APIs) and their transformation products inevitably enter waterways where they might cause adverse effects to aquatic organisms. Identifying the potential risks of APIs in the environment is therefore a goal and current strategic direction of environmental management described in the EU Strategic Approach to Pharmaceuticals in the Environment and the Green Deal. This is challenged by a paucity of monitoring and ecotoxicity data to adequately describe risks.In this study we analyze measured environmental concentrations (MECs) of APIs from 5933 sites in 25 European countries as documented in the EMPODAT database or collected by the German Environment Agency for the time period between 1997 and 2020. These data were compared with empirical data on the ecotoxicity of APIs from the U.S. EPA ECOTOX database. Although 1763 uniquely identifiable APIs are registered with the European Medicines Agency (EMA) for sale in the European Economic Area (EEA), only 312 (17.7%) of these are included in publicly available monitoring data, 36 (1.8%) compounds have sufficient ecotoxicological data to derive a PNEC, and only 27 (1.5%) compounds meet both the hazard and exposure data requirements required to to perform an environmental risk assessment according to EMA guidelines. Four of these compounds (14.8%) had a median risk quotient (RQ) > 1. Endocrine disruptors had the highest median RQ, with 7.0 and 5.6 for 17α-ethinyl-estradiol and 17β-estradiol respectively.A comparison of in-silico and empirical exposure data for 72 APIs demonstrated the high protectiveness of the current EMA guidelines, with predicted environmental concentrations (PECs) exceeding median MECs in 98.6% of cases, with a 100-fold median increase.This study describes the data shortfalls hindering an accurate assessment of the risk posed to European waterways by APIs, and identifies 68 APIs for prioritized inclusion in monitoring programs, and 66 APIs requiring ecotoxicity testing to fill current data gaps.

Environmental Monitoring and Risk Assessment of Pharmaceutical Residues Discharged from Large Livestock Complex in the Geum River Basin, South Korea

This study aims to collect water samples from two tributaries within the Geum River basin in South Korea, where large-scale livestock complexes are located, to quantify the measured environmental concentration (MEC) of pharmaceutical residues using a multiresidue analytical method developed with liquid chromatography–tandem mass spectrometry (LC-MS/MS), and to evaluate the environmental risks posed by the detected pharmaceuticals to aquatic organisms. The water samples were collected at a total of 17 points, including up-, middle-, and downstream of the Seoksong and Nonsan-Gangkyoung streams connected to the Geum River, from October 2018 to March 2019. A multiresidue analytical method using LC-MS/MS was developed to quantify 49 pharmaceuticals with hydrophilic lipophilic balance using solid phase extraction. The recovery rates varied between 67.23% and 136.98%, while the limits of quantification were from 3.99 to 46.32 ng/L. Ecotoxicological information on acute and chronic effect endpoints (e.g., EC50, NOEC, etc.) was obtained from the U.S. EPA ECOTOX Knowledgebase. Considering the worst-case scenario, the lowest observed effect endpoint (mainly NOEC) of the most sensitive species was selected, and predicted no effect concentration (PNEC) values were calculated by dividing the endpoint by an assessment factor (AF). The mean, minimum, and maximum MECs of pharmaceuticals were divided by PNECs to calculate risk quotient (RQ). Caffeine was detected in all sampling sites with a detection frequency of 100%. High levels of pharmaceuticals (9.212 μg/L of sulfathiazole, 8.479 μg/L of acetaminophen, and 5.885 μg/L of florfenicol) were detected. The RQ values exceeded 1 and reached up to 84.79 (high risk category) for acetaminophen, and were between 0.11 and 0.83 (moderate risk) for carbamazepine, etc. The RQs for the rest of the 15 substances were below 1 (low risk). In the future, further studies should be conducted to monitor other micropollutants, including industrial chemicals, pesticides, etc., at different locations of the Geum River basin, including livestock farms, pharmaceutical manufacturing facilities, wastewater treatment plants, and other facilities, for long-term period.

A One-Health environmental risk assessment of contaminants of emerging concern in London’s waterways throughout the SARS-CoV-2 pandemic

The SARS-CoV-2 pandemic had huge impacts on global urban populations, activity and health, yet little is known about attendant consequences for urban river ecosystems. We detected significant changes in occurrence and risks from contaminants of emerging concern (CECs) in waterways across Greater London (UK) during the pandemic. We were able to rapidly identify and monitor large numbers of CECs in n = 390 samples across 2019–2021 using novel direct-injection liquid chromatography-mass spectrometry methods for scalable targeted analysis, suspect screening and prioritisation of CEC risks. A total of 10,029 measured environmental concentrations (MECs) were obtained for 66 unique CECs. Pharmaceutical MECs decreased during lockdown in 2020 in the R. Thames (p ≤ 0.001), but then increased significantly in 2021 (p ≤ 0.01). For the tributary rivers, the R. Lee, Beverley Brook, R. Wandle and R. Hogsmill were the most impacted, primarily via wastewater treatment plant effluent and combined sewer overflows. In the R. Hogsmill in particular, pharmaceutical MEC trends were generally correlated with NHS prescription statistics, likely reflecting limited wastewater dilution. Suspect screening of ∼ 1,200 compounds tentatively identified 25 additional CECs at the five most impacted sites, including metabolites such as O-desmethylvenlafaxine, an EU Watch List compound. Lastly, risk quotients (RQs) ≥ 0.1 were calculated for 21 compounds across the whole Greater London freshwater catchment, of which seven were of medium risk (RQ ≥ 1.0) and three were in the high-risk category (RQ ≥ 10), including imidacloprid (RQ = 19.6), azithromycin (15.7) and diclofenac (10.5). This is the largest spatiotemporal dataset of its kind for any major capital city globally and the first for Greater London, representing ∼ 16 % of the population of England, and delivering a foundational One-Health case study in the third largest city in Europe across a global pandemic.

Evaluation of the Ecological Risk and the Development of Antimicrobial Resistance due to the Presence of the Macrolide Antibiotics Azithromycin and Clarithromycin in Romanian Aquatic Environment

The presence of antibiotics in the aquatic environment can result in the emergence of antibiotic-resistant pathogens. In this paper, our aim was to identify, quantify and distribute macrolide antibiotics in the aquatic environment in the river basins of Arges-Vedea, Buzau-Ialomita and Dobrogea-Litoral and of the Danube River. In the Arges-Vedea river basin area, clarithromycin was detected most frequently, i.e. 58.62%, in the Buzau-Ialomita river basin area with a frequency of 92.31% azithromycin was detected, and in the Dobrogea - Litoral river basin area clarithromycin was detected with a frequency of 35.48%. The highest concentration of azithromycin, 559 ng/L and of clarithromycin, 502 ng/L was recorded in the Buzau-Ialomita river basin. The ecotoxicological RQecotox risk was also estimated, as well as the risk of developing antibiotic resistance of RQAMR pathogens, by the ratio of Measured Environmental Concentration (MEC) and Predicted No Effect Concentrations (PNEC). The study also aimed to investigate the prevalence of antibiotic resistance in potentially pathogenic bacteria isolated from aquatic environments. Thus, for β-lactam antibiotics, E. coli strains isolated from the Danube River exhibited a very high level of resistance to ampicillin (51%) and high level to azithromycin (43%), cefazolin (38%), amoxicillin+clavulanic acid (36%) and cefoxitin (26%). Low and respectively, low level resistance was noticed for aztreonam (6%) and imipenem (4%).

Prioritization of pharmaceuticals and personal care products in the surface waters of Korea: Application of an optimized risk-based methods

The occurrence of PPCPs in aquatic environments and their potential adverse effects on aquatic organisms have raised worldwide concerns. To address this issue, a study was conducted to analyze 137 selected PPCPs in Korean surface waters, and an optimized risk-based prioritization was performed. The results revealed that 120 PPCPs were detected, with 98 quantified at concentrations ranging from few ng/L to 42,733 ng/L for metformin. The 95% upper confidence limit (UCL95) of the mean value of the measured environmental concentration (MEC) for Metformin was about eight times higher than the second highest compound, dimethyl phthalate, indicating that antidiabetic groups had the highest concentration among the therapeutic groups. An optimized risk-based prioritization was then assessed based on the multiplication of two indicators, the Frequency of Exceedance and the Extent of Exceedance of Predicted No-Effect Concentrations (PNECs), which can be calculated using the traditional risk quotient (RQ) approach. The study found that clotrimazole had the highest risk quotient value of 17.4, indicating a high risk to aquatic organisms, with seven and 13 compounds showing RQ values above 1 and 0.1, respectively. After considering the frequency of exceedance, clotrimazole still had the highest novel risk quotient (RQf) value of 17.4, with 99.6% of its MECs exceeding PNECs. However, the number of compounds with RQf values above 1 decreased from seven to five, with cetirizine and flubendazole being excluded. Furthermore, only 10 compounds exhibited RQf values above 0.1. The study also observed significant differences in the results between risk-based and exposure-based prioritization methods, with only five compounds, cetirizine, olmesartan, climbazole, sulfapyridine, and imidacloprid, identified in both methods. This finding highlights the importance of considering multiple methods for prioritizing chemicals, as different approaches may yield different results.

A framework for systematic microplastic ecological risk assessment at a national scale

Microplastic pollution is widespread in terrestrial and aquatic environments; however, a systematic assessment of the ecological risks of microplastics is lacking. This study collected research studies on microplastics in soil, aquatic and sediment environments, and screened 128 articles including 3459 sites to assess the ecological risks posed by microplastics in China following a literature quality assessment. We developed a systematic ecological risk assessment framework for microplastics in terms of spatial characterization, biotoxicity and anthropogenic impacts. The results of the pollution load index indicated that 74% and 47% of the soil and aquatic environments studied, respectively, faced a medium or higher level of pollution. Comparing predicted no effect concentrations (PNEC) and measured environmental concentrations (MECs), revealed that soil (97.70%) and aquatic (50.77%) environmental studies were at serious ecological risk from microplastics. The results of the pressure-state-response model showed that the microplastic pollution in Pearl River Delta was in a high-risk state. In addition, we found that ultraviolet radiation and rainfall exacerbate soil microplastic pollution, and higher river runoff may carry large amounts of microplastic from the source. The framework developed in this study will help assess the ecological risks of microplastics in the region to promote the mitigation of plastic pollution.

PERK: An R/Shiny application to predict and visualise concentrations of pharmaceuticals in the aqueous environment

Predicting the concentration of active pharmaceuticals ingredients (API) in the environment using modelling approaches is an important aspect in the assessment of their environmental risk, especially for the API with no or limited analytical detection methods. However, handling, validating, and incorporating diverse datasets, including API prescription/consumption data, metabolism, flow data, removal efficiency during wastewater treatment, and dilution factor for the modelling is often laborious and time-consuming. The aim of this manuscript is to evaluate R/Shiny based tool, PERK, to facilitate automated modelling and reporting predicted environmental concentration (PEC) of a comprehensive set of API in different environmental matrices. PERK helped to calculate PEC in wastewater influent, effluent, and river, and compare with measured environmental concentrations (MEC) for five catchments located in England. Prediction accuracy (PA), the ratio between PEC and MEC, can be also generated with the tool. PERK provides consistent interactive user-interface, enabling user to visualise the results with limited programming knowledge.

Management of Macrolide Antibiotics (Erythromycin, Clarithromycin and Azithromycin) in the Environment: A Case Study of Environmental Pollution in Lithuania

Of all the antibiotics used today for human treatment in the world, macrolide antibiotics—erythromycin, clarithromycin and azithromycin—stand out the most for misuse, and they were included as high-risk substances in the monitoring Watch List of Regulation 2018/840/EU. The aim of the present research was to investigate the level of target human pharmaceuticals’ prevalence in the environment by the substance flow analysis (SFA) approach and to determine the potential risks of the antibiotics for the environment. The target for the environmental investigations was Lithuania. For SFA, 2021 consumption input data were used, and such key processes as the consumption rate, disposal and distribution of pharmaceuticals in the environment were analyzed. The analysis revealed that the largest part of pharmaceutical contaminants (80.1%) enters wastewater treatment plants. The risk quotient approach was based on the determination of predicted environmental concentrations (PECs), measured environmental concentrations (MECs) and their ratio to the predicted no-effect environmental concentrations (PNECs). The analysis revealed that clarithromycin causes a high potential risk for the aquatic environment in effluents from the wastewater treatment plants (WWTP); PEC/PNEC > 7. For azithromycin and erythromycin, the estimated PEC values were between 0.1 and 1. Clarithromycin concentration in the effluents of two target WWTPs showed a significant risk quotient (MEC/PNEC) of higher than 7. Recommendations on how to reduce the release of pharmaceutical residues into the environment have been proposed in the framework of the environmental management system.

Comparative selective pressure potential of antibiotics in the environment

To guide both environmental and public health policy, it is important to assess the degree of antibiotic resistance selection pressure under measured environmental concentrations (MECs), and to compare the efficacy of different mitigation strategies to minimize the spread of resistance. To this end, the resistance selection and enrichment potential due to antibiotic emissions into the environment must be analysed from a life cycle perspective, for a wide range of antibiotics, and considering variations in the underlying fitness costs between different resistance mutations and genes. The aim of this study is to consistently derive fitness cost-dependent minimum selective concentrations (MSCs) from readily available bacterial inhibition data and to build MSC-based species sensitivity distributions (SSDs). These are then used to determine antibiotic-specific resistance selection concentrations predicted to promote resistance in 5% of exposed bacterial species (RSC5). Using a previously developed competition model, we provide estimated MSC10 endpoints for 2,984 antibiotic and bacterial species combinations; the largest set of modelled MSCs available to date. Based on constructed SSDs, we derive RSC5 for 128 antibiotics with four orders of magnitude difference in their ‘selective pressure potential’ in the environment. By comparing our RSC5 to MECs, we highlight specific environmental compartments (e.g. hospital and wastewater effluents, lakes and rivers), as well as several antibiotics (e.g. ciprofloxacin, norfloxacin, enrofloxacin, and tetracycline), to be scrutinized for their potential role in resistance selection and dissemination. In addition to enabling comparative risk screening of the selective pressure potential of multiple antibiotics, our SSD-derived RSC5 provide the point of departure for calculating new life cycle-based characterization factors for antibiotics to compare mitigation strategies, thereby contributing towards a ‘One-Health’ approach to tackling the global antibiotic resistance crisis.

Occurrence of pharmaceuticals in the wastewater of a Greek hospital: Combining consumption data collection and LC-QTOF-MS analysis

In this article we applied drug consumption approach and chemical analysis in parallel to investigate the concentrations of a large number of pharmaceuticals in different streams of a General Hospital. Drugs consumption data was collected during two periods (Period 1, 2) and the predicted environmental concentrations (PECs) were estimated for the wastewater of a building housing specific medical services (Point A) and for the entire hospital (Point B). Hospital wastewater samples (HWW) samples were also collected from these points and periods and the measured environmental concentrations (MEC) were determined using UHPLC-ESI-QTOF-MS/MS. According to consumption data, the highest number of drugs was consumed in the departments of Hematology, Intensive Care Unit, Cardiology, Internal Medicine, and Oncology, while the number of active substances used in the hospital was 413 (Period 1) and 362 (Period 2). For most substances, much higher PEC and MEC values were found at the HWW of Point A indicating that on-site treatment of this stream could be examined in the future. The application of wide-scope target analysis allowed the quantification of 122 compounds, while 21 additional substances were identified using suspect screening. The highest mean concentrations in Period 1 were found for acetaminophen (1100 μg/L) and rifaximin (723 μg/L), while in Period 2 for iopromide (458 μg/L) and acyclovir (408 μg/L). Among the detected compounds, 19 metabolites were determined. Atenolol acid, 1-hydroxy-midazolam and clopidogrel carboxylic acid were quantified at concentrations much higher than parent compounds indicating the importance of metabolites' monitoring in HWW. Calculation of PEC/MEC ratio for 36 pharmaceuticals showed sufficient correlation of these values for 19 % to 33 % of the substances depending on the examined period and sampling point. The parallel collection of drugs consumption data and chemical analysis give a thorough picture of the substances present in HWW and their main sources, facilitating decision-making for their better management.

Occurrence and risk assessment of fullerene colloidal nanoparticles by ultrasonic-assisted dispersive liquid-liquid extraction and high-performance liquid chromatography in surface waters

This paper presents a developed analytical technique for risk assessment of colloidal fullerene in surface waters by ultrasonic-assisted dispersive liquid-liquid extraction (UADLLE) and high-performance liquid chromatography ultraviolet-visible detector (HPLC-UV). Fullerene colloidal nanoparticles were synthesised and characterized by high-resolution transmission electron microscopy (HRTEM) and ultraviolet-visible spectroscopy (UV-Vis). Ultrasonication step, disperser solvent, and sodium chloride salt enhance the surface area of fullerene derivative aggregates for better contact and lowers the solubility of fullerene derivative to the aqueous solution, respectively promoting mass transfer of fullerene from aqueous into the organic phase. Several extraction parameters were optimized, and the optimal conditions were established: 5 mL toluene as extraction solvent (2 cycles); 200 mL water sample; 1% sodium chloride salt; 15 min ultrasonication, and 400 μL methanol as disperser solvent. The mean absolute recoveries established in drinking water, wastewater, and river water were 117%, 103%, and 93%, respectively. The proposed analytical technique was linear in the ranges between 0.25 μg L−1 – 250 μg L−1 with an r-squared of 0.9958. The limit of detection (LOD) determined from the signal-to-noise ratio of 3 was 0.11 μg L−1 and the limit of quantification (LOQ) from a signal-to-noise ratio of 10 was 0.38 μg L−1. The precision ranges from 2% to 11% and accuracy percent error ranged from 7%–14% for spiked concentration levels of 0.25 μg L−1, 50 μg L−1, and 250 μg L−1. The measured environmental concentration (MECs) for the fullerene in water samples ranged from not detected to 10.54 μg L−1 and ecological assessment showed the concentration level of the fullerene can pose risk. Overall, according to the author's knowledge, this is the earlier work on the occurrence and risk assessment of fullerene colloidal nanoparticles (C61-PCBM) in potable and wastewater on the African continent.

Risk Assessment of Personal Care Products, Pharmaceuticals, and Stimulants in Mgeni and Msunduzi Rivers, KwaZulu-Natal, South Africa

In this work, environmental occurrence and risk assessment of pharmaceuticals, personal care products (PPCPs), and stimulants are presented. A quantitative technique is described for ultrasonic-assisted solid-phase extraction (SPE) followed by GC-MS after derivatization of PPCPs; propylparaben, triclosan, carbamazepine, chloramphenicol, and stimulant caffeine. Ultrasonic-assisted extraction together with centrifugation were used to extract sediment samples collected from the Mgeni and Msunduzi rivers. An SPE procedure was used for cleanup and to concentrate selected compounds from diluted aqueous extracts. The final extracts were derivatized and analyzed with GC-MS in selected ion monitoring (SIM) mode. The recoveries of the analytes ranged from 66 to 108%. The method detection limits were (0.08–1.82 ng g−1 for solid and 0.08–10 μg L−1 for liquid) and quantification limits (0.42–5.51 ng g−1 for solid and 0.25–25 μg L−1 for liquid). The optimized method was applied in the evaluation of two rivers over 3 months in KwaZulu-Natal, South Africa. All targeted compounds were present in the environment at concentration levels between not detected to 174 ng g−1 and not detected to 30 μg L−1 for solids and aqueous environmental samples, respectively. A comparison of predicted no environmental effect concentration (PNECs) with measured environmental concentration (MECs) showed that these PPCPs present a high ecological risk to the receiving environment (agricultural lands and households). Our work is close to reality because we used MECs as opposed to using predicted environmental concentration (PECs) values, which are normally calculated from consumption, production of compound per year, and various estimated factors.

Characterization of ecotoxicological risks from unintentional mixture exposures calculated from European freshwater monitoring data: Forwarding prospective chemical risk management

Current regulatory chemical safety assessments do not acknowledge that ambient exposures are to multiple chemicals at the same time. As a result, potentially harmful exposures to unintentional mixtures may occur, leading to potential insufficient protection of the environment. The present study describes cumulative environmental risk assessment results for European fresh water ecosystems, based on the NORMAN chemical surface water monitoring database (1998–2016). It aims to characterize the magnitude of the mixture problem and the relative contribution of chemicals to the mixture risk, and evaluates how cumulative risks reduce when the acceptable risk per single chemical is fractionally lowered. Available monitoring data were curated and aggregated to 26,631 place-time combinations with at least two chemicals, of which 376 place-time combinations had at least 25 chemicals identified above the Limit of Detection. Various risk metrics were based on measured environmental concentrations (MECs). Mixture risk characterization ratio's (ΣRCRs) ≥ 1 were found for 39% of the place-time combinations, with few chemicals dominating the ΣRCR. Analyses of mixture toxic pressures, expressed as multi-substance Potentially Affected Fractions of species based on No Observed Effect Concentrations (msPAFNOEC), showed similar outcomes. Small fractional reductions of the ambient chemical concentrations give a steep increase of the percentage of sufficiently protected water bodies (i.e. ΣRCR < 1 and msPAFNOEC < 5%). Scientific and regulatory aspects of these results are discussed, especially with reference to the representativeness of the monitoring data for characterizing ambient mixtures, the robustness of the findings, and the possible regulatory implementation of the concept of a Mixture Allocation Factor (MAF) for prospective chemicals risk management. Although the monitoring data do not represent the full spectrum of ambient mixture exposures in Europe, results show the need for adapting policies to reach European Union goals for a toxic-free environment and underpin the utility and possible magnitude of a MAF.

Risk-based screening for prioritisation of organic micropollutants in Swedish freshwater

Concerns about environmental contamination by organic micropollutants (OMPs) are increasing, due to their potential bioaccumulative and toxic properties. This study evaluated the risk posed by OMPs to aquatic ecosystems in Swedish freshwaters. The assessment was based on measured environmental concentrations (MEC) of OMPs in surface waters upstream and downstream of Swedish wastewater treatment plants (WWTPs). A novel optimised risk quotient (RQf) was used to identify potential high-risk substances in the aquatic environment. A secondary objective was to assess the impact of WWTP effluent on aquatic ecosystems using a novel impact factor (I) based on the risk quotient (RQ). Among the 126 substances investigated, four compounds (metformin, N,N-dimethyltetradecylamine, oxazepam, and venlafaxine) were identified as likely to pose a risk to aquatic ecosystems in Swedish surface waters (RQf>1), and five compounds (clindamycin, gemfibrozil, sertraline, o-desmethylvenlafaxine, and diclofenac) were identified as posing a moderate risk to aquatic ecosystems ( 0.1 <RQf<1). WWTP effluent appeared to pose an environmental risk for all recipient sites, but the impact of calculated RQ was site-specific. These results can be used by authorities to prioritise OMPs and contaminated hotspots, in order to decrease negative impacts on aquatic ecosystems. SynopsisA novel optimised risk assessment approach for identification of high-concern organic micropollutants in aquatic environments.

Environmental contamination in a high-income country (France) by antibiotics, antibiotic-resistant bacteria, and antibiotic resistance genes: Status and possible causes.

Antimicrobial resistance (AMR) is a major global public health concern, shared by a large number of human and animal health actors. Within the framework of a One Health approach, actions should be implemented in the environmental realm, as well as the human and animal realms. The Government of France commissioned a report to provide policy and decision makers with an evidential basis for recommending or taking future actions to mitigate AMR in the environment. We first examined the mechanisms that underlie the emergence and persistence of antimicrobial resistance in the environment. This report drew up an inventory of the contamination of aquatic and terrestrial environments by AMR and antibiotics, anticipating that the findings will be representative of some other high-income countries. Effluents of wastewater treatment plants were identified as the major source of contamination on French territory, with spreading of organic waste products as a more diffuse and incidental contamination of aquatic environments. A limitation of this review is the heterogeneity of available data in space and time, as well as the lack of data for certain sources. Comparing the French Measured Environmental Concentrations (MECs) with predicted no effect concentrations (PNECs), fluoroquinolones and trimethoprim were identified as representing high and medium risk of favoring the selection of resistant bacteria in treated wastewater and in the most contaminated rivers. All other antibiotic molecules analyzed (erythromycin, clarithromycin, azithromycin, tetracycline) were at low risk of resistance selection in those environments. However, the heterogeneity of the data available impairs their full exploitation. Consequently, we listed indicators to survey AMR and antibiotics in the environment and recommended the harmonization of sampling strategies and endpoints for analyses. Finally, the objectives and methods used for the present work could comprise a useful example for how national authorities of countries sharing common socio-geographic characteristics with France could seek to better understand and define the environmental dimension of AMR in their particular settings.