Comprehensive monitoring of organic micro-pollutants in surface and groundwater in the surrounding of a solid-waste treatment plant of Castellón, Spain

Linking chemical surface water monitoring and pesticide regulation in selected European countries

The progress in chemical analytics and understanding of pesticide dynamics in surface waters allows establishing robust data on compounds with frequent exceedances of quality standards. The current chemical, temporal, and spatial coverage of the pesticide monitoring campaigns differs strongly between European countries. A questionnaire revealed differences in monitoring strategies in seven selected European countries; Nordic countries prioritize temporal coverage, while others focus on spatial coverage. Chemical coverage has increased, especially for non-polar classes like synthetic pyrethroids. Sweden combines monitoring data with agricultural practices for derived quantities, while the Netherlands emphasizes spatial coverage to trace contamination sources. None of the EU member states currently has established a process for linking chemical surface water monitoring data with regulatory risk assessment, while Switzerland has recently established a legally defined feedback loop. Due to their design and objectives, most strategies do not capture concentration peaks, especially 2-week composite samples, but also grab samples. Nevertheless, for substances that appear problematic in many data sets, the need for action is evident even without harmonization of monitoring programs. Harmonization would be beneficial, however, for cross-national assessment including risk reduction measures.

High resolution mass spectrometry-based screening for the comprehensive investigation of organic micropollutants in surface water and wastewater from Pasto city, Colombian Andean highlands

The complexity of the aquatic environment scenario, including the impact of urban wastewater, together with the huge number of potential hazardous compounds that may be present in waters, makes the comprehensive characterization of the samples an analytical challenge, particularly in relation to the presence of organic micropollutants (OMPs). Nowadays, the potential of high-resolution mass spectrometry (HRMS) for wide-scope screening in environmental samples is out of question. Considering the physicochemical characteristics of OMPs, the coupling of liquid (LC) and gas chromatography (GC) to HRMS is mandatory. In this work, we have explored the combined use of LC and GC coupled to Quadrupole-Time-of-Flight Mass Spectrometry (QTOF MS) for screening of surface water and wastewater samples from Pasto (Nariño), a town of the Colombian Andean highlands (average altitude 2527 m), located in an important agricultural area. The upper basin of the Pasto River is impacted by phytosanitary products used in different crops, whereas the domestic wastewater is directly discharged into the river without any treatment, enhancing the anthropogenic impact on the water quality. The OMP searching was made by target (standards available) and suspect (without standards) approaches, using home-made databases containing >2000 compounds. Up to 15 pesticides (7 insecticides, 6 fungicides and 2 herbicides) were identified in the sampling point of the Pasto River up to the town, while no pharmaceuticals were found at this site, illustrating the impact of agriculture practices. On the contrary, 14 pharmaceuticals (7 antibiotics and 3 analgesics, among others) were found in river samples collected in the middle and down to the town sites, revealing the impact of the urban population. Interestingly, some transformation products, including metabolites, such as carbofuran-3-hydroxy and 4-acetylamino antipyrine were identified in the screening. Based on these data, future monitoring will apply target quantitative LC-MS/MS methods for the most relevant compounds identified.

The main strategies for soil pollution apportionment: A review of the numerical methods

Nowadays, a large number of compounds with different physical and chemical properties have been determined in soil. Environmental behaviors and source identification of pollutants in soil are the foundation of soil pollution control. Identification and quantitative analysis of potential pollution sources are the prerequisites for its prevention and control. Many efforts have made to develop methods for identifying the sources of soil pollutants. These efforts have involved the measurement of source and receptor parameters and the analysis of their relationships via numerical statistics methods. We have comprehensively reviewed the progress made in the development of source apportionment methodologies to date and present our synthesis. The numerical methods, such as spatial geostatistics analysis, receptor models, and machine learning methods are addressed in depth. In most cases, however, the effectiveness of any single approach for source apportionment remains limited. Combining multiple methods to address soil quality problems can reduce uncertainty about the sources of soil pollution. This review also constructively highlights the key strategies of combining mathematical models with the assessment of chemical profiles to provide more accurate source attribution. This review intends to provide a comprehensive summary of source apportionment methodologies to help promote further development.

Recent advances in remediation strategies for mitigating the impacts of emerging pollutants in water and ensuring environmental sustainability

The proliferation of emerging pollutants (EPs), encompassing a range of substances such as phthalates, phenolics, pharmaceuticals, pesticides, personal care products, surfactants, and disinfection agents, has become a significant global concern due to their potential risks to the environment and human well-being. Over the past two decades, numerous research studies have investigated the presence of EPs in wastewater and aquatic ecosystems, with the United States Environmental Protection Agency (USEPA) categorizing these newly introduced chemical compounds as emerging contaminants due to their poorly understood impact. EPs have been linked to adverse health effects in humans, including genotoxic and cytotoxic effects, as well as conditions such as obesity, diabetes, cardiovascular disease, and reproductive abnormalities, often associated with their estrogenic action. Microalgae have shown promise in the detoxification of both inorganic and organic contaminants, and several large-scale microalgal systems for wastewater treatment have been developed. However, the progress of algal bioremediation can be influenced by accidental contaminations and operational challenges encountered in pilot-scale research. Microalgae employ various processes, such as bioadsorption, biouptake, and biodegradation, to effectively remediate EPs. During microalgal biodegradation, complex chemical compounds are transformed into simpler substances through catalytic metabolic degradation. Integrating algal bioremediation with existing treatment methodologies offers a viable approach for efficiently eliminating EPs from wastewater. This review focuses on the use of algal-based biological remediation processes for wastewater treatment, the environmental impacts of EPs, and the challenges associated with implementing algal bioremediation systems to effectively remove emerging pollutants.

Occurrence and sources of residues of drugs of abuse in an urban aquifer: Chemical analysis and solute transport modelling

This study investigated the occurrence and potential sources of residues of drugs of abuse in an urban aquifer beneath the City of Ljubljana using water analysis and a solute transport model designed to predict nitrogen distribution. Samples were collected from three sources: 28 wastewater samples (24-h composites), 4 aquifer-recharging river samples (grab), and 22 groundwater samples. The samples were analysed for residues of commonly (ab)used licit drugs (nicotine and alcohol), medications of abuse (morphine, methadone, codeine, and ketamine), and illicit drugs (tetrahydrocannabinol - THC, cocaine, amphetamines, and heroin) using liquid-liquid (alcohol residue) and solid-phase extraction, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Additionally, we used solute transport modelling to predict the spatial distribution of drug residues in the aquifer and their potential sources. Nicotine (up to 45,7 ng/L), cotinine (up to 5.86 ng/L), trans-3'-hydroxycotinine (up to 0.528 ng/L) and benzoylecgonine (up to 0.572 ng/L) were the most commonly detected drug residues in groundwater, followed by cocaine (<LOQ). In comparison, methadone (0.054 ng/L) was detected only once. A higher prevalence of residues of drugs of abuse was observed in samples obtained at the south-eastern edge of the aquifer, downgradient from the main zone of urbanisation, agreeing with model predictions. Although drug residues were detected in river water, modelling suggests that the city's leaky sewer system is the primary source of drug residues.

Occurrence of organic pollutants in the River Itchen and River Test-two chalk streams in Southern England, UK

The River Itchen and River Test, two chalk streams in Southern England, are sites of special scientific interest. These ecosystems face a number of environmental pressures from anthropogenic inputs of organic pollutants. Hence, we investigated the occurrence of these chemicals within the two catchments. Spot water samples (1 L) were collected at nineteen sites along the catchment on two occasions (March and June 2019). Samples were extracted (HLB-L sorbent disks) and analysed using high-resolution liquid chromatography-quadrupole-time-of-flight mass spectrometry and gas chromatography-mass spectrometry. Compounds were identified against commercially available databases. Using this approach, we found 115 pharmaceutical and personal care products, 81 plant protection products and 35 industrial chemicals. This complex mixture of pollutants covered a range of physico-chemical properties and included priority substances in the EU Water Framework Directive or currently on the third Watch List. Both rivers had similar chemical profiles for both months. Herbicides and fungicides were dominant in the spring, whereas insecticides occurred more frequently in the summer. Point discharges from wastewater treatment plants were the main source of pharmaceutical and personal care products. Agricultural activities were the main contributor to the presence of plant protection products. The impact of these organic chemicals on the ecology, particularly on macroinvertebrate biodiversity, is unknown and warrants further investigation. Our suspect screening approach could guide future toxicological investigations to assess the environmental impacts of these diverse chemicals.

Seasonal drivers and risks of aquatic pesticide pollution in drought and post-drought conditions in three Mediterranean watersheds

The Western Cape in South Africa has a Mediterranean climate, which has in part led to an abundance of agriculturally productive land supporting the wheat, deciduous fruit, wine, and citrus industries. South Africa is the leading pesticide user in Sub-Saharan Africa. There is limited data on the pesticide pollution of surface water over different seasons in low- and middle-income countries. We evaluated the seasonal drivers of aquatic pesticide pollution in three river catchments (Berg, Krom, and Hex Rivers) from July 2017 to June 2018 and April to July 2019, using 48 passive samplers. Our sampling followed the most severe drought (2015-2018) since recordings in 1960. Thus, our analyses focus on how drought and post-drought conditions may affect in-stream pesticide concentrations and loads. Samples were analyzed for 101 pesticide compounds using liquid chromatography - high-resolution mass spectrometry. Environmental Quality Standards (EQS) were used to assess the risks. We detected 60 pesticide compounds across the sampling periods. Our results indicate that all samples across all three catchments contained at least three pesticides and that the majority (83%) contained five or more pesticides. Approximately half the number of pesticides were detected after the drought in 2018. High concentration sums of pesticides (>1 μg/L) were detected over long time periods in the Hex River Valley (22 weeks) and in Piketberg (four weeks). Terbuthylazine, imidacloprid, and metsulfuron-methyl were detected in the highest concentrations, making up most of the detected mass, and were frequently above EQS. The occurrence of some pesticides in water generally correlated with their application and rainfall events. However, those of imidacloprid and terbuthylazine did not, suggesting that non-rainfall-driven transport processes are important drivers of aquatic pesticide pollution. The implementation of specific, scientifically sound, mitigation measures against aquatic pesticide pollution would require comprehensive pesticide application data as well as a targeted study identifying sources and transport processes for environmentally persistent pesticides.

Evaluation of sample preparation methods for suspect and non-target screening in water, sediment, and biota samples using gas chromatography coupled to high-resolution mass spectrometry

In this study, the sample preparation methods were proposed for the suspect and non-target screening (SNTS) using gas chromatography coupled to high-resolution mass spectrometry in the aquatic environment. The pretreatment methods were evaluated based on detection rates, recoveries, and screening detection limits (SDLs) for 316 substances spiked into surface water, sediment, and biota samples. The detection rates of the spiked compounds were 92.1 % and 98.7 % by the sample preparation methods for water (solid-phase extraction using HLB cartridge) and sediment (ultrasonic extraction (USE) with HLB cartridge clean-up), respectively. Similarly, USE with HLB cartridge clean-up gave the highest detection rate (87.9 %) for biota samples; however, additional pretreatment method using deactivated silica gel clean-up was necessary for the detection of persistent organic pollutants (POPs). The SDL ranges of spiked compounds by the suggested pretreatment methods were 0.01-23.5 ng/L for surface water, 0.02-37.5 ng/g dry weight for sediment, and 0.01-12.2 ng/g wet weight for biota. Although some pollutants, such as POPs had SDLs that were higher than the levels normally detected in the aquatic environment as reported in previous studies, the analytical methods suggested in the present study were satisfactory for the SNTS of most pollutants originated from anthropogenic sources.

PWC-based evaluation of groundwater pesticide pollution in the Júcar River Basin

Predicting pesticides' behavior in the environment is necessary to anticipate and minimize their adverse effects. Despite the use of pesticides in Spain is increasing, the implementation and use of predictive mathematical models is seldomly done in practice due to the lack of available data. In this original work, the Pesticide Root Zone Model version 5 (PRZM 5) mathematical model under the Pesticide in Water Concentration 1.52 (PWC) interface has been applied to model pesticide behavior in nine groundwater bodies located inside the Júcar River Basin (JRB) in Spain. Mathematical modeling allowed calculating the maximum concentration of pesticides after completing the calibration process. Bromacil, terbuthylazine, atrazine, desethyl-terbuthylazine, and terbumeton concentrations in groundwater were simulated between 2006 and 2019. Results show that the maximum pesticide concentration value on every well exceeds the current Spanish Maximum Concentration Limit (0.1 μg/L). PRZM 5 was able to reproduce pesticide concentration observations over time despite the limited amount of available data. This study contributes to assessing environmental risks caused by the use of pesticides inside the JRB and can potentially be applied in other areas of interest.

Enhanced photocatalytic degradation of caffeine using Co-Zn/Al2O3 nanocomposite

This work focuses on the synthesis and characterization of photocatalytic activity of Co-Zn/Al₂O₃ nanocomposite obtained by calcination of Co-loaded Zn/aluminum layered double hydroxide by wet impregnation method. The catalyst was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), BET and UV-DRS. The evaluation of catalytic activity was investigated for the degradation of emerging pharmaceutical pollutant caffeine in aqueous solutions under UV irradiation. The process parameters were optimized for the maximum removal of caffeine. A maximum caffeine removal of 92% was obtained with the optimal conditions at the catalytic dosage of 0.5 g/L, contact time of 50 min, initial concentration of 50 mg/L, and pH of 9.5. The batch experimental data coincide well with the pseudo first order kinetic model, the rate constant of 0.012 min^-1, with the R² value of 0.875-0.938. The regeneration study reveals that the catalyst has high stability and maximum removal efficiency. Hence, the synthesized nanocatalyst is considered a potential photo catalyst for removing the pharmaceutical pollutant caffeine from aqueous solutions.

Are preserved coastal water bodies in Spanish Mediterranean basin impacted by human activity? Water quality evaluation using chemical and biological analyses

The Spanish Mediterranean basin is particularly susceptible to climate change and human activities, making it vulnerable to the influence of anthropogenic contaminants. Therefore, conducting comprehensive and exhaustive water quality assessment in relevant water bodies of this basin is pivotal. In this work, surface water samples from coastal lagoons or estuaries were collected across the Spanish Mediterranean coastline and subjected to target and suspect screening of 1,585 organic micropollutants by liquid chromatography coupled to ion mobility separation and high resolution mass spectrometry. In total, 91 organic micropollutants could be confirmed and 5 were tentatively identified, with pharmaceuticals and pesticides being the most prevalent groups of chemicals. Chemical analysis data was compared with data on bioanalysis of those samples (recurrent aryl hydrocarbon receptor (AhR) activation, and estrogenic receptor (ER) inhibition in wetland samples affected by wastewater streams). The number of identified organic contaminants containing aromatic rings could explain the AhR activation observed. For the ER antagonistic effects, predictions on estrogenic inhibition potency for the detected compounds were used to explain the activities observed. The integration of chemical analysis with bioanalytical observations allowed a comprehensive overview of the quality of the water bodies under study.

Overarching issues on relevant pesticide transformation products in the aquatic environment: A review

The intensification of agricultural production during the last decades has forced the rapid increase in the use of pesticides that finally end up in the aquatic environment. Albeit well-documented, pesticides continue to raise researchers' attention, because of their potential adverse impacts on the environment and, inevitably, humans. Once entering the aquatic bodies, pesticides undergo biotic and abiotic processes, resulting in transformation products (TPs) that sometimes are even more toxic than the parent compounds. A substantial shift of the scientific interest in the TPs of pesticides has been observed since their environmental fate, occurrence and toxicity is still in its formative stage. In an ongoing effort to expand the existing knowledge on the topic, several interesting works have been performed mostly in European countries, such as France, Germany, Italy, Switzerland, Greece, and Spain that counts the highest number of relevant publications. Pesticide TPs have been also studied to a lesser extent in Asia, North and South America. To this end, the main objective of this review is to delineate the global occurrence, fate, toxicity as well as the analytical challenges related to pesticide TPs in surface, ground, and wastewaters, with the view to contribute to a better understanding of the environmental problems related with TPs formation. The concentration levels of the TPs, ranging from the low ng/L to high μg/L scale and distributed worldwide. Ultimately, an attempt to predict the acute and chronic toxicity of TPs has been carried out with the aid of an in-silico approach based on ECOSAR, revealing increased chronic toxicity for the majority of the identified TPs, despite the change they underwent, while a small portion of them presented serious acute toxicity values.

Nontargeted Screening Using Gas Chromatography-Atmospheric Pressure Ionization Mass Spectrometry: Recent Trends and Emerging Potential

Gas chromatography–high-resolution mass spectrometry (GC–HRMS) is a powerful nontargeted screening technique that promises to accelerate the identification of environmental pollutants. Currently, most GC–HRMS instruments are equipped with electron ionization (EI), but atmospheric pressure ionization (API) ion sources have attracted renewed interest because: (i) collisional cooling at atmospheric pressure minimizes fragmentation, resulting in an increased yield of molecular ions for elemental composition determination and improved detection limits; (ii) a wide range of sophisticated tandem (ion mobility) mass spectrometers can be easily adapted for operation with GC–API; and (iii) the conditions of an atmospheric pressure ion source can promote structure diagnostic ion–molecule reactions that are otherwise difficult to perform using conventional GC–MS instrumentation. This literature review addresses the merits of GC–API for nontargeted screening while summarizing recent applications using various GC–API techniques. One perceived drawback of GC–API is the paucity of spectral libraries that can be used to guide structure elucidation. Herein, novel data acquisition, deconvolution and spectral prediction tools will be reviewed. With continued development, it is anticipated that API may eventually supplant EI as the de facto GC–MS ion source used to identify unknowns.

The relevant role of ion mobility separation in LC-HRMS based screening strategies for contaminants of emerging concern in the aquatic environment

Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promising technique for (non-)target/suspect analysis of micropollutants in complex matrices. IMS separates ionized compounds based on their charge, shape and size facilitating the removal of co-eluting isomeric/isobaric species. Additionally, IMS data can be translated into collision cross-section (CCS) values, which can be used to increase the identification reliability. However, IMS-HRMS for the screening of contaminants of emerging concern (CECs) have been scarcely explored. In this study, the role of IMS-HRMS for the identification of CECs in complex matrices is highlighted, with emphasis on when and with which purpose is of use. The utilization of IMS can result in much cleaner mass spectra, which considerably facilitates data interpretation and the obtaining of reliable identifications. Furthermore, the robustness of IMS measurements across matrices permits the use of CCS as an additional relevant parameter during the identification step even when reference standards are not available. Moreover, an effect on the number of true and false identifications could be demonstrated by including IMS restrictions within the identification workflow. Data shown in this work is of special interest for environmental researchers dealing with the detection of CECs with state-of-the-art IMS-HRMS instruments.

Passive sampling with suspect screening of polar pesticides and multivariate analysis in river catchments: Informing environmental risk assessments and designing future monitoring programmes

Pollution of surface water by polar pesticides is a major environmental risk, particularly in river catchments where potable water supplies are abstracted. In these cases, there is a need to understand pesticide sources, occurrence and fate. Hence, we developed a novel strategy to improve water quality management at the catchment scale using passive sampling coupled to suspect screening and multivariate analysis. Chemcatcher® passive sampling devices were deployed (14 days) over a 12 month period at eight sites (including a water supply works abstraction site) in the Western Rother, a river catchment in South East England. Sample extracts (n = 197) were analysed using high-resolution liquid chromatography-quadrupole-time-of-flight mass spectrometry and compounds identified against a commercially available database. A total of 128 pesticides from different classes were found. Statistical analysis of the qualitative screening data was used to identify clusters of pesticides with similar spatiotemporal pollution patterns. This enabled pesticide sources and fate to be identified. At the water supply works abstraction site, spot sampling and passive sampling were found to be complementary, however, the passive sampling method in conjunction with suspect screening detected 50 pesticides missed by spot sampling combined with targeted analysis. Geospatial data describing pesticide application rates was found to be poorly correlated to their detection frequency using the Chemcatcher®. Our analysis prioritised 61 pesticides for inclusion in a future water quality risk assessment at the abstraction site. It was also possible to design a seasonal monitoring programme to effectively characterise the spatiotemporal pesticide profiles within the catchment. A work flow of how to incorporate passive sampling coupled to suspect screening into existing regulatory monitoring is proposed. Our novel approach will enable water quality managers to target the mitigation (non-engineered actions) of pesticide pollution within the catchment and hence, to better inform drinking water treatment processes and save on operational costs.

Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

To explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5-6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater

Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.

Emerging pollutants in Nigeria: A systematic review

Emerging pollutants represent a group of synthetic or naturally occurring compounds that are not normally monitored within the environment but can enter into the environment and cause different adverse ecological and health effects. This systematic review identified the various emerging pollutants in Nigeria. The following databases, ScienceDirect, PubMed, Google Scholar, and African Journals OnLine (AJOL) were searched to identify studies on pollutants of emerging concerns in Nigeria. A total of 933 articles were identified out of which 30 articles were selected to be eligible for the study. Over 250 emerging pollutants were identified and divided into 9 major groups which are personal care products, pharmaceuticals, industrial chemicals, polycyclic aromatic hydrocarbons, volatile organic compounds, pesticides, mycotoxins, radionuclides and electromagnetic radiations (Gamma radiation) and other pollutants of emerging concerns such as microbes, microplastics, and particulate matter. These pollutants are found in water bodies and underground waters, soils and sediments, biological systems, and ambient air at different concentrations with seasonal variations. Some of these pollutants act as endocrine disruptors, β-adrenergic receptors agonist blockers, oxidative stress inducers and can cause genetic alterations in DNA and epigenetic reprogramming through global DNA methylation, gene-specific CpG methylation and microRNA expression. Emerging pollutants of public health concern in Nigeria are on the increase and are threat to both ecological and human health.

Ecological risk assessment of pesticides in the Mijares River (eastern Spain) impacted by citrus production using wide-scope screening and target quantitative analysis

The widespread use of pesticides, especially in agricultural areas, makes necessary to control their presence in surrounding surface waters. The current study was designed to investigate the occurrence and ecological risks of pesticides and their transformation products in a Mediterranean river basin impacted by citrus agricultural production. Nineteen sites were monitored in three campaigns distributed over three different seasons. After a qualitative screening, 24 compounds was selected for subsequent quantitative analysis. As expected, the lower section of the river was most contaminated, with total concentration >5 µg/L in two sites near to the discharge area of wastewater treatment plants. The highest concentrations were found in September, after agricultural applications and when the river flow is reduced. Ecological risks were calculated using two mixture toxicity approaches (Toxic Unit and multi-substance Potentially Affected Fraction), which revealed high acute and chronic risks of imidacloprid to invertebrates, moderate-to-high risks of diuron, simazine and 2,4-D for primary producers, and moderate-to-high risks of thiabendazole for invertebrates and fish. This study shows that intensive agricultural production and the discharge of wastewater effluents containing pesticide residues from post-harvest citrus processing plants are threatening freshwater biodiversity. Further actions are recommended to control pesticide use and to reduce emissions.

Efficacy of atrazine pesticide reduction in aqueous solution using activated carbon, ozone and a combination of both

In this study, the reduction of the emerging organic contaminant atrazine in water, was investigated by adsorption, oxidation and a combination of both technologies. Adsorption tests were performed using method ASTM D3860-98 with two types of activated carbon: powdered activated carbon and granular activated carbon. For the oxidation tests, advanced ozone oxidation technology was used. Finally, in the combined tests, firstly adsorption treatment was applied followed by oxidation and then the order was reversed. We studied the contaminant removal percentage using different treatments at various reaction times. Results for the different treatments under study showed that, for an initial atrazine concentration of 0.7 mg L^-1 and a dose of 16 mg L^-1 of powdered activated carbon, with contact times of 60 min, 24 h and 48 h, percentage reductions of the contaminant of 81%, 92% and 94% respectively were obtained. For the same concentration of contaminant, but instead using granular activated carbon, the percentage reduction of atrazine at 60 min was 2%, this percentage rising to 34% and 35% after 24 and 48 h of contact time, respectively. For the same initial contaminant concentration, when ozone was applied at a dose of 19.7 mg L^-1, and with a reaction time of 18 min, a reduction of atrazine of 93% was obtained, but oxidation by-products were also produced. For the combined treatments, with the same initial concentration of contaminant and the same doses of carbon and ozone as previously indicated, better contaminant reductions were obtained when the treatment started with activated carbon followed by ozone, achieving a 90% reduction of atrazine observing a 17 minute contact time with powdered activated carbon and a 3 day contact time using the granulated carbon. When the order was reversed by starting with ozone, the contact time was 52 min and 4 days, respectively.

Pretreatment and determination methods for benzimidazoles: An update since 2005

Benzimidazoles, commonly used as pesticides and veterinary drugs, have posed a threat to human health and the environment due to unreasonable use and lack of valid regulation. Therefore, an up-to-date and comprehensive summary of the pretreatment and analytical approaches in different substrates is urgently needed. The present review consequently updates and covers various newly developed pretreatment methods (e.g., cationic micellar precipitation, magnetic-solid phase extraction, hollow fiber liquid phase microextraction, disperse liquid-liquid microextraction-solidified floating organic drop, stir cake sorptive extraction, solid phase microextraction method, QuEChERS, and molecular imprinted polymer-based methods) since 2005. The review also elaborates and discusses different determination methods (e.g., newly developed HPLC and related methods, improved spectrofluorimetry methods, capillary electrophoresis, and the electrochemical sensor). Furthermore, some critical points and prospects are highlighted, to describe the trends in this area.

Pesticides and their degradates in groundwater reflect past use and current management strategies, Long Island, New York, USA

Long Island, New York, has a mix of urban/suburban to agricultural/horticultural land use and nearly 3 million residents that rely on a sole-source aquifer for drinking water. The analysis of shallow groundwater (<40 m below land surface) collected from 54 monitoring wells across Long Island detected 53 pesticides or pesticide degradates. Maximum concentrations for individual pesticides or pesticide degradates ranged from 3 to 368,000 ng/L. The highest concentrations and most frequent pesticide detections occurred in samples collected from the pesticide management (PM) network, set in an agricultural/horticultural area in eastern Long Island with coordinated pesticide management by state and local agencies. The other two networks (Suffolk and Nassau/Queens) were set in suburban and urban areas, respectively, and had less frequent detections and lower pesticide concentrations than the PM network. Pesticide detections and concentration patterns (herbicide, insecticide, or fungicide) differed among the three networks revealing broad differences in land use. The predominance of fungicides metalaxyl, 1H-1,2,4-triazole (propiconazole/myclobutanil degradate), and 4-hydroxychlorothalonil (HCTL, chlorothalonil degradate) in samples from the PM network reflects their intensive use in agricultural settings. Total fungicide concentrations in the PM network ranged from <10 to >300,000 ng/L. The widespread detection of imidacloprid and triazine herbicides, simazine and atrazine, reveal a mixture of current and past use pesticides across the Long Island region. Low concentrations (<200 ng/L) of the triazines in the Suffolk and Nassau/Queens networks may reflect a change in land use and application. Acetanilide herbicides and aldicarb have been discontinued for 20 and 40 years, respectively, yet the concentrations of their degradates were among the highest observed in this study. Acetanilide (total concentrations up to 10,000 ng/L) and aldicarb degradates (up to 270 ng/L) are present in the PM network at much lower concentrations than previous Long Island studies and reflect changes in agricultural practices and pesticide management.

Emerging organic compounds in European groundwater

In Europe, emerging organic compounds (EOCs) in groundwater is a growing research area. Prioritisation for monitoring EOCs in Europe was formalised in 2019 through the development of the first voluntary groundwater watch list (GWWL). Despite this, groundwater occurrence data in the peer reviewed literature for Europe has not been reviewed to date. Questions surrounding the effect, toxicity, movement in the subsurface and unsaturated zone make the process of regulating EOC use difficult. The aim in Europe is to develop a unified strategy for the classification, and prioritisation of EOCs to be monitored in groundwater. This paper compiles evidence from the recent published studies from across Europe, since 2012, when the last major literature global review of EOCs in groundwater took place. A total of 39 studies were identified for review based on specific selection criteria (geography, publication date, sample size>10, inclusion of EOCs data). Data on specific compounds, and associated meta-data, are compiled and reviewed. The two most frequently detected EOCs, carbamazepine and caffeine, occurred in groundwater at concentrations of up to 2.3 and 14.8 μg/L, respectively. The most frequently reported category of compounds were 'Pharmaceuticals'; a highly studied group with 135 compounds identified within 31 of the 39 studies. In Europe, the majority of reviewed studies (23) were at a regional scale, looking specifically at EOCs in a specific city or aquifer. The use of analytical methods is not uniform across Europe, and this inevitably influences the current assessment of EOCs in groundwater. A correlation between the number of compounds analysed for, and the number detected in groundwater highlights the need for further studies, especially larger-scale studies throughout Europe. For the development of EU and national regulation, further work is required to understand the occurrence and impacts of EOCs in groundwater throughout Europe and elsewhere.

Comparison of preconcentration methods for nontargeted analysis of natural waters using HPLC-HRMS: Large volume injection versus solid-phase extraction

Nontargeted analysis of water samples using liquid chromatography combined with high‐resolution mass spectrometers is an emerging approach for surface water monitoring and evaluation of water treatment processes. In this study, sample preconcentration via direct, large volume injection with 500 μL and 1000 μL injection volumes was compared to SPE regarding analytical performance parameters in targeted and nontargeted workflows. In targeted analysis, the methods were evaluated in terms of LOD and intrabatch precision of the selected compounds, whereas in nontargeted analysis, the number of detected unknown compounds, the method's intra‐batch precision, and the retention time versus molecular mass pattern of the detected unknowns were evaluated. In addition, a novel intensity drift correction method was developed that is not based on quality control samples and makes use of the signals obtained for continuously infused reference compounds, which are conventionally utilized for online mass drift correction. It could be demonstrated that the new correction method significantly reduced the bias introduced by instrumental drift and is important for the reliable intercomparison of different nontargeted methods. Intercomparison of results showed that the 1000 μL large volume injection method revealed the best performance in terms of precision under repeatability conditions of measurement as well as lower LODs for targeted compound analysis. In nontargeted analysis, the SPE method detected a higher number of unknown compounds but exhibited also a higher uncertainty of measurement caused by matrix effects.

Occurrence and ecological risks of pharmaceuticals in a Mediterranean river in Eastern Spain

Pharmaceuticals are biologically active molecules that may exert toxic effects to a wide range of aquatic organisms. They are considered contaminants of emerging concern due to their common presence in wastewaters and in the receiving surface waters, and the lack of specific regulations to monitor their environmental occurrence and risks. In this work, the environmental exposure and risks of pharmaceuticals have been studied in the Mijares River, Eastern Mediterranean coast (Spain). A total of 57 surface water samples from 19 sampling points were collected in three monitoring campaigns between June 2018 and February 2019. A list of 40 compounds was investigated using a quantitative target UHPLC-MS/MS method. In order to complement the data obtained, a wide-scope screening of pharmaceuticals and metabolites was also performed by UHPLC-HRMS. The ecological risks posed by the pharmaceutical mixtures were evaluated using species sensitivity distributions built with chronic toxicity data for aquatic organisms. In this study, up to 69 pharmaceuticals and 9 metabolites were identified, out of which 35 compounds were assessed using the quantitative method. The highest concentrations in water corresponded to acetaminophen, gabapentin, venlafaxine, valsartan, ciprofloxacin and diclofenac. The compounds that were found to exert the highest toxic pressure on the aquatic ecosystems were principally analgesic/anti-inflammatory drugs and antibiotics. These were: phenazone > azithromycin > diclofenac, and to a lower extent norfloxacin > ciprofloxacin > clarithromycin. The monitored pharmaceutical mixtures are expected to exert severe ecological risks in areas downstream of WWTP discharges, with the percentage of aquatic species affected ranging between 65% and 82% in 3 out of the 19 evaluated sites. In addition, five antibiotics were found to exceed antibiotic resistance thresholds, thus potentially contributing to resistance gene enrichment in environmental bacteria. This work illustrates the wide use and impact of pharmaceuticals in the area under study, and the vulnerability of surface waters if only conventional wastewater treatments are applied. Several compounds included in this study should be incorporated in future water monitoring programs to help in the development of future regulations, due to their potential risk to the aquatic environment.

Exposure to Environmental Levels of Pesticides Stimulates and Diversifies Evolution in Escherichia coli toward Higher Antibiotic Resistance

Antibiotic resistance is one of the most challenging issues in public health. Antibiotics have been increasingly used not only for humans and animals but also for crop protection as pesticides. Thus, antibiotics often coexist with pesticides in some environments. To investigate the effects of the co-occurring, nonantibiotic pesticides on the development of antibiotic resistance, we conducted long-term exposure experiments using an Escherichia coli K-12 model strain. The results reveal that (1) the exposure to pesticides (in mg/L) alone led to the emergence of mutants with significantly higher resistance to streptomycin; (2) the exposure to pesticides (in μg/L) together with a subinhibitory level (in high μg/L) of ampicillin synergistically stimulated the selection of ampicillin resistance and the cross-resistance to other antibiotics (i.e., ciprofloxacin, chloramphenicol, and tetracycline). Distinct and diversified genetic mutations emerged in the resistant mutants selected from the coexposure to both pesticides and ampicillin. The genetic mutations likely caused a holistic transcriptional regulation (e.g., biofilm formation, oxidative stress defense) when grown under antibiotic stress and led to increased antibiotic resistance. Together, these findings provide important fundamental insights into the development of antibiotic resistance and the resistance mechanisms under environmentally relevant conditions where antibiotics and nonantibiotic micropollutants coexist.

Identification of Aquifer Recharge Sources as the Origin of Emerging Contaminants in Intensive Agricultural Areas. La Plana de Castellón, Spain

In urban, industrial, and agricultural areas, a vast array of contaminants may be found because they are introduced into the aquifers by different recharge sources. The emerging contaminants (ECs) correspond to unregulated contaminants, which may be candidates for future regulation depending on the results of research into their potential effects on health and on monitoring data regarding their occurrence. ECs frequently found in wastewater, such as acetaminophen, carbamazepine, primidone, and sulfamethoxazole, may be good indicators of the introduction of the reclaimed water to the aquifers. The resistance of the ECs to removal in wastewater treatment plants (WWTPs) causes them to be appropriate sewage markers. Plana de Castellón (Spain) is a coastal area that has been characterized by intensive citrus agriculture since the 1970s. Traditionally, in the southern sector of Plana de Castellón, 100% of irrigation water comes from groundwater. In recent years, local farmers have been using a mixture of groundwater and reclaimed water from wastewater treatment plants (WWTPs) to irrigate the citrus. The aims of the present study were: (i) to assess the occurrences, spatial distributions, and concentrations of selected ECs, including 32 antibiotics, 8 UV filters, and 2 nonsteroidal anti-inflammatory drugs, in groundwater in a common agricultural context; (ii) to identify the recharge (pollution) sources acting as the origin of the ECs, and (iii) to suggest ECs as indicators of reclaimed water arrival in detrital heterogeneous aquifers. The obtained data provided relevant information for the management of water resources and elucidated the fate and behavior of emerging contaminants in similar contexts.

Investigation of pesticides and their transformation products in the Júcar River Hydrographical Basin (Spain) by wide-scope high-resolution mass spectrometry screening

The Water Framework Directive 2000/60/EC implemented by the European Union established as the main objectives to achieve a "good ecological and chemical status" of the surface water and a "good quantitative and chemical status" of groundwater bodies. One of the major pressures affecting water bodies comes from the use of pesticides and their potential presence in the water ecosystems. For this purpose, the reliable determination of pesticides and their transformation products (TPs) in natural waters (both surface and groundwater) is required. The high number of compounds potentially reaching the aquatic environment makes extraordinary difficult, if not impossible, to investigate all these compounds even using the most powerful analytical techniques. Among these, liquid chromatography coupled to high-resolution mass spectrometry is emphasized due to its strong potential for detection and identification of many organic contaminants thanks to the accurate-mass full spectrum acquisition data. This work focuses on wide-scope screening of many pesticides and their TPs in surface water and groundwater samples, collected between March and May 2017, in the Júcar River Hydrographical Basin, Spain. For this purpose, a home-made database containing more than 500 pesticides and TPs was employed. Analyses performed by liquid chromatography coupled to quadrupole-time of flight mass spectrometry (LC-QTOF MS) allowed the identification of up to 27 pesticides and 6 TPs. The most detected compounds in groundwater were the herbicides atrazine, simazine, terbuthylazine, and their TPs (atrazine-desethyl, terbumeton-desethyl and terbuthylazine-desethyl). Regarding surface water, the fungicides carbendazim, thiabendazole and imazalil, the herbicide terbutryn and the TP terbumeton-desethyl were also detected. These results illustrate the wide use of these compounds (in the present or in the recent past) in the area under study and the vulnerability of the water bodies, and are in accordance with previous findings in other water bodies of the different Spanish Hydrographic systems.

Non-targeted Screening in Environmental Monitoring Programs

Contaminant monitoring programs have been tasked with understanding the fate and transport of toxic chemicals in the environment. Mass spectrometry based methods have traditionally been developed to maximize sensitivity and accuracy of a select set of target compounds. As mass spectrometry methods have advanced, so has the breadth of questions proposed by environmental chemists. Incorporating these methods in chemical monitoring programs provides large data sets to explore the effects of complex mixtures on environmental systems.

Use of passive sampling and high resolution mass spectrometry using a suspect screening approach to characterise emerging pollutants in contaminated groundwater and runoff

Groundwater systems are being increasingly used to provide potable and other water supplies. Due to human activities, a range of organic pollutants is often detected in groundwater. One source of groundwater contamination is via stormwater infiltration basins, however, there is little information on the types of compounds present in these collection systems and their influence on the underlying groundwater. We developed an analytical strategy based on the use of passive sampling combined with liquid chromatography/high resolution quadrupole-time-of-flight mass spectrometry for screening for the presence of pesticide and pharmaceutical compounds in groundwater and stormwater runoff. Empore™ disk-based passive samplers (SDB-RPS and SDB-XC sorbents) were exposed, using for the first time a new specially designed deployment rig, for 10 days during a rainfall event in five different stormwater infiltration systems around Lyon, France. Stormwater runoff and groundwater (via a well, upstream and downstream of each basin) was sampled. Exposed Empore™ disks were solvent extracted (acetone and methanol) and the extracts analysed using a specific suspect compound screening workflow. High resolution mass spectrometry coupled with a suspect screening approach was found to be a useful tool as it allows a more comprehensive analysis than with targeted screening whilst being less time consuming than non-targeted screening. Using this analytical approach, 101 suspect compounds were tentatively identified, with 40 of this set being subsequently confirmed. The chemicals detected included fungicides, herbicides, insecticides, indicators of human activity, antibiotics, antiepileptics, antihypertensive and non-steroidal anti-inflammatory drugs as well as their metabolites. Polar pesticides were mainly detected in groundwater and pharmaceuticals were more frequently found in runoff. In terms of detection frequency of the pollutants, groundwater impacted by infiltration was found not to be significantly more contaminated than non-impacted groundwater.

Comprehensive investigation of pesticides in Brazilian surface water by high resolution mass spectrometry screening and gas chromatography-mass spectrometry quantitative analysis

In this work, a comprehensive investigation on the occurrence of pesticides in the Paraná 3 hydrographic basin of Paraná State, Brazil, was made by application of wide-scope screening based on ultra-high performance liquid chromatography (LC) and gas chromatography (GC) both coupled to quadrupole time-of-flight mass spectrometry (QTOF MS). The use of two complementary techniques, such as GC-QTOF MS and LC-QTOF MS, allowed screening a large number of compounds with different polarity and volatility. This screening approach was applied to 17 samples, enabling the detection of fifty-two pesticides and six metabolites. In a second step, an specific research was made on the herbicide atrazine, one of the most frequent compounds in samples, and its major transformation products (TPs), which were quantitatively analyzed by dispersive liquid-liquid microextraction (DLLME) followed by GC-MS measurement. Twenty-one agricultural streams from the Paraná 3 hydrographic basin were sampled twice in 2017, each time along six successive weeks. Additional samples were also collected after rain events exceeding 10 mm. In total, 407 samples were quantitatively analyzed by DLLME/GC-MS. Atrazine concentrations did not exceed the maximum permitted concentration of 2 μg L^-1 according to Brazilian legislation, and only one surface water sample, collected after precipitation events, was slightly above this value (2.89 μg L^-1). The maximum concentrations for the TPs desethylatrazine and deisopropylatrazine were 0.80 and 1.22 μg L^-1, respectively. Based on the quantification results, a map was produced showing the occurrence of atrazine and its TPs in the area under study. This is the first time that the presence of agrochemicals is evaluated in the Paraná 3 hydrographic basin.

Occurrence, fate and environmental risk assessment of the organic microcontaminants included in the Watch Lists set by EU Decisions 2015/495 and 2018/840 in the groundwater of Spain

This paper aims to review the existing occurrence data in Spanish groundwater (GW) for the emerging organic contaminants (EOCs) defined in the surface water Watch Lists of Decisions 2015/495/EU and 2018/840/EU since these contaminants are likely to reach GW bodies because surface waters show close interaction with GW. These two lists include 20 substances: 9 pesticides (5 neonicotinoids, 2 carbamates, 1 oxadiazole and 1 semicarbazone), 6 pharmaceuticals (diclofenac and 5 antibiotics), 3 estrogens, 1 UV filter (2-ethylhexyl-4-methoxycinnamate, EHMC) and 1 antioxidant (2,6-di-tert-butyl-4-methylphenol, BHT). Most of these substances are usually detected at low ng/L concentration range or not detected in the GW bodies of Spain. However, eventually they are reported at concentrations>100ng/L (e.g., imidacloprid, methiocarb, diclofenac, macrolide antibiotics, ciprofloxacin, EHMC and BHT). Consequently, it is required to set up drinking water standards, and/or GW threshold quality values because GW is a valuable water resource worldwide. Overall, GW is less contaminated than other water bodies, such as rivers, suggesting that aquifers possess a natural attenuation capacity and/or are less vulnerable than rivers to contamination. Nevertheless, the natural hydrogeochemical processes that control the fate and transformation of these substances during infiltration and in the aquifer have been barely investigated so far. The concentrations of the target EOCs are used to calculate hazard quotients (HQs) in the Spanish GW bodies as an estimation of their ecotoxicity and in order to compare somehow their chemical quality with respect to those of surface water. Due to the limited ecotoxicity data for most EOCs, HQs can only be calculated for few substances. The results pointed out the risk posed by the anti-inflammatory diclofenac towards Ceriodaphnia dubia (HQ=21) and the medium risk associated to the antibiotic erythromycin for Brachionus calyciflorus (HQ=0.46).

Exploration of environmental contaminants in honeybees using GC-TOF-MS and GC-Orbitrap-MS

This study reports an analytical approach by gas chromatography and high-resolution mass spectrometry (HRMS) intended to be used for investigation of non-targeted environmental contaminants in honeybees. The approach involves a generic extraction and analysis with two GC-HRMS systems: time-of-flight and Orbitrap analyzers, GC-TOF-MS, and GC-Orbitrap-MS operated in electron-impact ionization (EI) mode. The workflow for screening of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, molecular formula of representative ions (molecular and fragment ions) was provided for those with an accurate mass scoring (error < 5 ppm). This methology was applied for screening environmental contaminants in 75 samples of adult honeybee. This approach has provided the tentative identification of environmental contaminants belonging to different chemical groups, among them, PAHs, phthalates and synthetic musks. Residues of veterinary treatments used in apiculture were also detected in the honeybee samples.

Occurrence and overlooked sources of the biocide carbendazim in wastewater and surface water

Carbendazim is a fungicide commonly used as active substance in plant protection products and biocidal products, for instance to protect facades of buildings against fungi. However, the subsequent occurrence of this fungicide and potential endocrine disruptor in the aqueous environment is a major concern. In this study, high resolution mass spectrometry shows that carbendazim can be detected with an increasing abundance from the source to the mouth of the River Rhine. Unexpectedly, the abundance of carbendazim correlates poorly with that of other fungicides used as active ingredients in plant protection products (r² of 0.32 for cyproconazole and r² of 0.57 for propiconazole) but it correlates linearly with that of pharmaceuticals (r² of 0.86 for carbamazepine and r² of 0.89 for lamotrigine). These results suggest that the occurrence of carbendazim in surface water comes mainly from the discharge of treated domestic wastewater. This hypothesis is further confirmed by the detection of carbendazim in wastewater effluents (n = 22). In fact, bench-scale leaching tests of textiles and papers revealed that these materials commonly found in households could be a source of carbendazim in domestic wastewater. Moreover, additional river samples collected nearby two paper industries indicate that the discharge of their treated process effluents is also a source of carbendazim in the environment. While characterizing paper and textile as overlooked sources of carbendazim, this study also shows the biocide as a possible ubiquitous wastewater contaminant that would require further systematic and worldwide monitoring due to its toxicological properties.

Pesticide Risks in Small Streams-How to Get as Close as Possible to the Stress Imposed on Aquatic Organisms

The risks associated with pesticides in small streams remain poorly characterized. The challenges reside in understanding the complexities of (1) the highly dynamic concentration profiles of (2) several hundred active substances with (3) differing seasonality. The present study addressed these three challenges simultaneously. Five small streams in catchments under intensive agricultural land use were sampled using half-day composite samples from March to August 2015. Of 213 active substances quantified using liquid chromatography-high resolution mass spectrometry, a total of 128 was detected at least at one of the sites. Ecotoxicological acute and/or chronic quality criteria were exceeded for a total of 32 different active substances. The evaluation of risks over time revealed the necessity to evaluate the sequences of different active substances that are imposed on aquatic organisms. In contrast, a substance-specific perspective provides only a very limited assessment. Scenarios for reduction of either temporal resolution, number of substances or seasonal coverage were defined. It could be shown that risks can be underestimated by more than a factor of 10 in vulnerable catchments and that an increased temporal resolution is essential to cover acute risks but that a focused selection of substances is a possibility to reduce expenditures.

Sorption, mobility, and bioavailability of PBDEs in the agricultural soils: Roles of co-existing metals, dissolved organic matter, and fertilizers

Polybrominated diphenyl ethers (PBDEs) are common pollutants released from electronic waste (e-waste) dismantling and recycling activities. Our city-wide survey of agricultural soils in Qingyuan (40 sampling sites), where e-waste recycling has been active, observed exceedance of PBDEs above background levels (average of 251.9ngg^-1, 87 times the regional baseline concentration) together with elevated levels of metals/metalloids at the contamination hotspots, such as As (180.4mgkg^-1), Cu (100.7mgkg^-1), Zn (93.4mgkg^-1), Pb (37.8mgkg^-1), Cr (15.1mgkg^-1), and Cd (0.3mgkg^-1). Hence, a twenty-cycle batch sorption test on composite soil samples from the e-waste site was conducted to study the fate of BDE-28 (2,4,4'-tribromodiphenyl ether) and BDE-99 (2,2',4,4',5-pentabromodiphenyl ether) under the influence of co-existing trace elements (TEs) (Cu, Pb, Zn, and Cd, which exceeded Chinese Environmental Quality Standard for Soils), dissolved organic matter (extracted from local peat), and locally available commercial fertilizer. The results showed that the presence of TEs barely affected the sorption of BDEs, probably because the low concentration of BDEs in the environment resulted in nearly complete sorption onto the soil. In contrast, metals sorption onto soil was promoted by the presence of BDEs. The mobility of BDE-28 was higher than BDE-99 in water leaching tests, while the leaching concentration of BDE-99 was further reduced in simulated acid rain possibly due to protonation of π-accepting sites in soil organic matter. In the freshly spiked soil, BDEs of greater hydrophobicity and larger molecular size exhibited higher bioavailability (due to greater affinity to Tenax extraction), which was contrary to the field contaminated soil. Similarly, the co-occurrence of metals and fertilizer increased the bioavailability of newly sorbed BDE-99 more than BDE-28 in the soil. These results illustrate the need to holistically assess the fate and interactions of co-existing organic and inorganic pollutants in the agricultural soils.

Laccase-immobilized dendritic nanofibrous membranes as a novel approach towards the removal of bisphenol A

Laccase enzymes from Rhus vernificera were covalently bound on hyperbranched polyethyleneimine/polyethersulfone (HPEI/PES) electrospun nanofibrous membranes and used for the removal of bisphenol A (BPA) from water. The laccase enzyme was anchored on the dendritic membranes through the abundant peripheral amine groups on the HPEI using glutaraldehyde as a crosslinker. The membranes were characterized with attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and ultraviolet-visible spectroscopy and correlative light and electron microscopy (CLEM). Furthermore, contact-angle analyses, pure water flux measurements and rejection analyses were carried out. CLEM showed that the enzymes were uniformly dispersed on the nanofibres while SEM analysis revealed that the nanofibres had an average diameter of 354 ± 37 nm. EDS showed the presence of Cu, which is the active entity in laccase enzymes. The laccase-modified membranes were hydrophilic (50°-53° contact angle) and exhibited high BPA rejection of 89.6% as compared to the 52.4% demonstrated by pristine PES. The laccase-modified membranes also maintained a constant permeate flux (7.07 ± 5.54 L/m² h) throughout the filtration process. Recyclability studies indicated that the membranes still maintained a high BPA removal of up to 79% even after four filtration cycles.

Recent applications of gas chromatography with high-resolution mass spectrometry

Gas chromatography coupled to high-resolution mass spectrometry is a powerful analytical method that combines excellent separation power of gas chromatography with improved identification based on an accurate mass measurement. These features designate gas chromatography with high-resolution mass spectrometry as the first choice for identification and structure elucidation of unknown volatile and semi-volatile organic compounds. Gas chromatography with high-resolution mass spectrometry quantitative analyses was previously focused on the determination of dioxins and related compounds using magnetic sector type analyzers, a standing requirement of many international standards. The introduction of a quadrupole high-resolution time-of-flight mass analyzer broadened interest in this method and novel applications were developed, especially for multi-target screening purposes. This review is focused on the development and the most interesting applications of gas chromatography coupled to high-resolution mass spectrometry towards analysis of environmental matrices, biological fluids, and food safety since 2010. The main attention is paid to various approaches and applications of gas chromatography coupled to high-resolution mass spectrometry for non-target screening to identify contaminants and to characterize the chemical composition of environmental, food, and biological samples. The most interesting quantitative applications, where a significant contribution of gas chromatography with high-resolution mass spectrometry over the currently used methods is expected, will be discussed as well.

Occurrence and fate of illicit drugs and pharmaceuticals in wastewater from two wastewater treatment plants in Costa Rica

Chemical analysis of raw wastewater in order to assess the presence of biological markers entering a wastewater treatment plant can provide objective information about the health and lifestyle of the population connected to the sewer system. This work was performed in a tropical country of Central America, Costa Rica, with the aim of extending this knowledge to new world regions. This work is the first to report wastewater-based epidemiological data on the use of illicit drugs in this region of the world. Composite wastewater samples from the influents of two different wastewater treatment facilities and surface water samples from surrounding areas were collected applying the best practice protocol and analysed to investigate the occurrence and fate of selected illicit drugs of abuse and pharmaceuticals. Results showed the presence of chemical indicators of the classic drugs cocaine and cannabis at high concentration levels, besides the moderate presence of the opiates codeine and morphine. Neither the worldwide commonly used psychoactive substances of abuse such as synthetic phenethylamines, nor pharmaceuticals from the family of benzodiazepines were detected, demonstrating the spatial differences in drug use among different world regions. In addition, effluent wastewater samples were analysed and compared to influent concentrations in order to evaluate the decrease in concentration of the targeted analytes through two treatment technologies. As a final step, a wide-scope qualitative screening, including hundreds of suspect compounds, was applied in order to have a better knowledge on the presence of pharmaceuticals in waters and to assess the potential impact of the treated wastewater into the receiving aquatic ecosystems.

Passive sampling as a tool for identifying micro-organic compounds in groundwater

The paper presents the use of a simple and cost efficient passive sampling device with integrated active carbon with which to test the possibility of determining the presence of micro-organic compounds (MOs) in groundwater and identifying the potential source of pollution as well as the seasonal variability of contamination. Advantage of the passive sampler is to cover a long sampling period by integrating the pollutant concentration over time, and the consequently analytical costs over the monitoring period can be reduced substantially. Passive samplers were installed in 15 boreholes in the Maribor City area in Slovenia, with two sampling campaigns covered a period about one year. At all sampling sites in the first series a total of 103 compounds were detected, and 144 in the second series. Of all detected compounds the 53 most frequently detected were selected for further analysis. These were classified into eight groups based on the type of their source: Pesticides, Halogenated solvents, Non-halogenated solvents, Domestic and personal, Plasticizers and additives, Other industrial, Sterols and Natural compounds. The most frequently detected MO compounds in groundwater were tetrachloroethene and trichloroethene from the Halogenated solvents group. The most frequently detected among the compound's groups were pesticides. Analysis of frequency also showed significant differences between the two sampling series, with less frequent detections in the summer series. For the analysis to determine the origin of contamination three groups of compounds were determined according to type of use: agriculture, urban and industry. Frequency of detection indicates mixed land use in the recharge areas of sampling sites, which makes it difficult to specify the dominant origin of the compound. Passive sampling has proved to be useful tool with which to identify MOs in groundwater and for assessing groundwater quality.

Recent developments in polyfluoroalkyl compounds research: a focus on human/environmental health impact, suggested substitutes and removal strategies

Between the late 1940s and early 1950s, humans manufactured polyfluoroalkyl compounds (PFCs) using electrochemical fluorination and telomerisation technologies, whereby hydrogen atoms are substituted by fluorine atoms, thus conferring unnatural and unique physicochemical properties to these compounds. Presently, there are wide ranges of PFCs, and owing to their bioaccumulative properties, they have been detected in various environmental matrices and in human sera. It has thus been suggested that they are hazardous. Hence, this review aims at highlighting the recent development in PFC research, with a particular focus on perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), the most studied and predominantly found PFCs in various environmental matrices, although recent reports have included perfluorobutane sulfonate (PFBS), which was previously regarded as innocuously harmless, when compared to its counterparts, PFOA and PFOS. As such, proper investigations are thus required for a better understanding of short-chain PFC substitutes, which have been suggested as suitable replacements to long-chained PFCs, although these substitutes have also been suggested to pose various health risks comparable to those associated with long-chain PFCs. Similarly, several novel technologies, such as PFC reduction using zero-valent iron, including removal at point of use, adsorption and coagulation, have been proposed. However, regardless of how efficient removers some of these techniques have proven to be, short-chain PFCs remain a challenge to overcome for scientists, in this regard.

Monitoring a large number of pesticides and transformation products in water samples from Spain and Italy

Assessing the presence of pesticides in environmental waters is particularly challenging because of the huge number of substances used which may end up in the environment. Furthermore, the occurrence of pesticide transformation products (TPs) and/or metabolites makes this task even harder. Most studies dealing with the determination of pesticides in water include only a small number of analytes and in many cases no TPs. The present study applied a screening method for the determination of a large number of pesticides and TPs in wastewater (WW) and surface water (SW) from Spain and Italy. Liquid chromatography coupled to high-resolution mass spectrometry (HRMS) was used to screen a database of 450 pesticides and TPs. Detection and identification were based on specific criteria, i.e. mass accuracy, fragmentation, and comparison of retention times when reference standards were available, or a retention time prediction model when standards were not available. Seventeen pesticides and TPs from different classes (fungicides, herbicides and insecticides) were found in WW in Italy and Spain, and twelve in SW. Generally, in both countries more compounds were detected in effluent WW than in influent WW, and in SW than WW. This might be due to the analytical sensitivity in the different matrices, but also to the presence of multiple sources of pollution. HRMS proved a good screening tool to determine a large number of substances in water and identify some priority compounds for further quantitative analysis.

Comprehensive strategy for pesticide residue analysis through the production cycle of gilthead sea bream and Atlantic salmon

Plant ingredients and processed animal proteins are alternative feedstuffs for fish feeds in aquaculture. However, their use can introduce contaminants like pesticides that are not previously associated with marine Atlantic salmon and gilthead sea bream farming. This study covers the screening of around 800 pesticides by gas chromatography (GC) and liquid chromatography (LC) coupled to high resolution time-of-flight mass spectrometry in matrices throughout the entire marine food production chain. Prior to analysis of real-world samples, the screening methodology was validated for 252 pesticides to establish the screening detection limit. This was 0.01 mg kg^-1 for 113 pesticides (45%), 0.05 mg kg^-1 for 73 pesticides (29%) and >0.05 mg kg^-1 for 66 pesticides (26%). After that, a quantitative methodology based on GC coupled to tandem mass spectrometry with atmospheric pressure chemical ionization source (GC-APCI-MS/MS) was optimized for the pesticides found in the screening. Although several polar pesticides, of which pirimiphos methyl and chlorpyriphos-methyl were most dominant, were found in plant material and feeds based on these ingredients, none of them were observed in fillets of Atlantic salmon and gilthead sea bream fed on these feeds.

Expanded Target-Chemical Analysis Reveals Extensive Mixed-Organic-Contaminant Exposure in U.S. Streams

Surface water from 38 streams nationwide was assessed using 14 target-organic methods (719 compounds). Designed-bioactive anthropogenic contaminants (biocides, pharmaceuticals) comprised 57% of 406 organics detected at least once. The 10 most-frequently detected anthropogenic-organics included eight pesticides (desulfinylfipronil, AMPA, chlorpyrifos, dieldrin, metolachlor, atrazine, CIAT, glyphosate) and two pharmaceuticals (caffeine, metformin) with detection frequencies ranging 66-84% of all sites. Detected contaminant concentrations varied from less than 1 ng L-1 to greater than 10 μg L-1, with 77 and 278 having median detected concentrations greater than 100 ng L-1 and 10 ng L-1, respectively. Cumulative detections and concentrations ranged 4-161 compounds (median 70) and 8.5-102 847 ng L-1, respectively, and correlated significantly with wastewater discharge, watershed development, and toxic release inventory metrics. Log10 concentrations of widely monitored HHCB, triclosan, and carbamazepine explained 71-82% of the variability in the total number of compounds detected (linear regression; p-values: < 0.001-0.012), providing a statistical inference tool for unmonitored contaminants. Due to multiple modes of action, high bioactivity, biorecalcitrance, and direct environment application (pesticides), designed-bioactive organics (median 41 per site at μg L-1 cumulative concentrations) in developed watersheds present aquatic health concerns, given their acknowledged potential for sublethal effects to sensitive species and lifecycle stages at low ng L-1.

Monitoring of emerging pollutants in Guadiamar River basin (South of Spain): analytical method, spatial distribution and environmental risk assessment

Guadiamar River is located in the southwest of the Iberian Peninsula and connects two protected areas in the South of Spain: Sierra Morena and Doñana National Park. It is sited in an area affected by urban, industrial and agriculture sewage pollution and with tradition on intensive mining activities. Most of the studies performed in this area have been mainly focused on the presence of heavy metals and, until now, little is known about the occurrence of other contaminants such as emerging organic pollutants (EOPs). In this work, an analytical method has been optimized and validated for monitoring of forty-seven EOPs in surface water. The analytical method has been applied to study the distribution and environmental risk of these pollutants in Guadiamar River basin. The analytical method was based on solid-phase extraction and determination by liquid chromatography-triple quadrupole-tandem mass spectrometry. The 60 % of the target compounds were found in the analyzed samples. The highest concentrations were found for two plasticizers (bisphenol A and di(2-ethyhexyl)phthalate, mean concentration up to 930 ng/L) and two pharmaceutical compounds (caffeine (up to 623 ng/L) and salicylic acid (up to 318 ng/L)). This study allowed to evaluate the potential sources (industrial or urban) of the studied compounds and the spatial distribution of their concentrations along the river. Environmental risk assessment showed a major risk on the south of the river, mainly due to discharges of wastewater effluents.