Development of a comprehensive screening method for more than 300 organic chemicals in water samples using a combination of solid-phase extraction and liquid chromatography-time-of-flight-mass spectrometry

Exploration of novel solid-phase extraction modes for analysis of multiclass emerging contaminants

Solid-phase extraction (SPE) has gained an essential role in environmental analytical chemistry. Classic off-line SPE coupled with LC-MS/MS systems creates powerful analytical procedures for ultratrace analysis of contaminants of emerging concern (CECs) in water. But, being associated with tedious work and large consumption of materials, alternative SPE modes are becoming interesting. As so, the study focuses on development, evaluation, and overall comparison of established and novel SPE modes. Off-line SPE, dispersive micro SPE (DMSPE), and 'fast' single-pump on-line SPE were explored, using commercially available sorbents. Their efficiency was evaluated on their performance in water analysis of 20 multiclass CECs. Hydrophilic-lipophilic sorbent and mixture of C18/C8 sorbents were the best choice for off-line and DMSPE, respectively. All optimized SPE modes coupled with UHPLC-MS/MS reached environmentally-relevant limits of detection (LODs 0.1-12 ng L-1), acceptable repeatability (<20 % RSD), and exhibited less than ±30 % matrix effects in real river water sample. Among all, on-line SPE showed a potential to fully replace the well-established off-line SPE and even improve analytical performance. This was due to the best repeatability (<10 % RSD), automatization, simplicity, the highest multiplexing capacity, as well as comparable LODs of <2 ng L-1. DMSPE is, on the other hand, the most innovative and could be seen as a quick and green alternative to off-line SPE for determination of semi-to-nonpolar CECs, but within sub-10 ng L-1 range. Overall, the study shows workflow for the exploration of important and promising sample pretreatment techniques in water analysis. Comparison of the developed three SPE-UHPLC-MS/MS methods suggests that alternative SPE modes can compete with the well-established off-line SPE and can even improve the analysis quality if properly applied.

Occurrence and Health Risks of Organic Micropollutants in Tap Water in Dalian

Organic micropollutants (OMPs) in tap water may pose risks to human health. Previous studies on the potential health risks of OMPs in tap water may have underestimated the potential health risks of OMPs due to their limited coverage in target pollutants and incomplete toxicity data. In this study, tap water samples were collected in 37 sampling sites in Dalian, China. More than 1,200 target pollutants were screened by combining screening analysis and target analysis. A total of 93 OMPs were detected, with concentration summation ranging from 157 to 1.7 × 104 ng/L among different sampling sites. A total of 17 OMPs (12 agrochemicals, 3 pharmaceuticals and personal care products, and 2 other compounds) were detected in over 80% of the sampling sites. Especially, imidacloprid, tebuconazole, and atrazine-desethyl were found in all the sampling sites. Computational toxicology models were adopted to predict the missing toxicity threshold values of the identified chemicals. Noncarcinogenic risks were estimated to be negligible among all the sampling sites, while carcinogenic risks at six sites were above 10-6 but below 10-4, indicating non-negligible risks. Griseofulvin contributed the most to the carcinogenic risk. This study offers valuable insights that can guide future initiatives to safeguard tap water safety.

High resolution mass spectrometry (HRMS) determination of drugs in wastewater and wastewater based epidemiology in Cadiz Bay (Spain)

Multi-residue methods for the determination of the myriad of compounds of emerging concern (CECs) entering in the environment are key elements for further assessment on their distribution and fate. Here, we have developed an analytical protocol for the simultaneous analysis of 195 prescription, over-the-counter, and illicit drugs by using a combination of solid phase extraction (SPE) and determination by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). The method was applied to the analysis of influent sewage samples from 3 wastewater treatment plants (WWTPs) from Cadiz Bay (SW Spain), enabling the quantification of more than 100 pharmaceuticals, 19 of them at average concentrations higher than 1 μg L^-1, including caffeine (92 μg L^-1), paracetamol (72 μg L^-1), and ibuprofen (56 μg L^-1), as well as several illicit drugs (e.g., cocaine). Wastewater based epidemiology (WBE) was applied for 27 of the detected compounds to establish their consumption in the sampling area, which has been never attempted before. Caffeine, naproxen, and salicylic acid stood out because of their high consumption (638, 51, and 20 g d^-1·1000pop^-1, respectively). Regarding illicit drugs, cocaine showed the highest frequency of detection and we estimated an average consumption of 3683 mg d^-1·1000pop^-1 in Cadiz Bay. The combination of new HRMS methods, capable of discriminating thousands of chemicals, and WBE will allow for a more comprehensive characterization of chemical substances and their consumption in urban environments in the near future.

Occurrence, potential sources, and risk assessment of pharmaceuticals and personal care products in atmospheric particulate matter in Hanoi, Vietnam

Pharmaceutical and personal care products (PCPPs) were recently recognized as emerging pollutants due to their potential for adverse health and environmental impacts. One potential route of exposure, atmospheric particulate matter (APM), for polar PPCP chemicals has to date received limited attention. This study screened for 190 polar PPCP chemicals in outdoor APM samples collected from two locations in Hanoi, Vietnam, and predictions of source and potential effects on human health are presented. Day and night, as well as dry and rainy seasonal samples, were taken, and samples screened by LC-TOF, using sequential window acquisition and all theoretical fragment ion spectra method. Eleven PPCP chemicals were detected above the LOD and in more than one sample. The ∑11PPCP chemicals ranged from 0.61 to 21.9 ng m^-3 (median 2.07 ng m^-3), with between 2 and 6 compounds identified in individual samples (median 4). The ∑11PPCP chemicals collected near a heavy traffic area was greater than that in a populated residential zone. Night concentrations were significantly greater than day in both dry and rainy seasons (p < 0.05). Butyl methoxydibenzoylmethane, benzophenone-3, acetaminophen, cotinine, and fluorescent brightener 71 were detected in > 50% of samples. These are typically found in sunscreens, cosmetics, antipyretics, tobacco, and dyes. The DI_air, hazard quotient (HQ), and hazard index (HI) for adults and children at sampling sites were estimated. The HQ for both adults and children were orders of magnitude less than the risk or were close to or whichever. APM does appear to be a potential additional secondary exposure source of PPCP chemicals to the environment and more work is needed to identify if sources are local or ubiquitous and if there is a greater health risk.

Assessing the protection gap for mobile and persistent chemicals during advanced water treatment - A study in a drinking water production and wastewater treatment plant

Persistent and mobile (PM) chemicals spread quickly in the water cycle and can reach drinking water. If these chemicals are also toxic (PMT) they may pose a threat to the aquatic environment and drinking water alike, and thus measures to prevent their spread are necessary. In this study, nontarget screening and cell-based toxicity tests after a polarity-based fractionation into polar and non-polar chemicals are utilized to assess and compare the effectiveness of ozonation and filtration through activated carbon in a wastewater treatment and drinking water production plant. Especially during wastewater treatment, differences in removal efficiency were evident. While median areas of non-polar features were reduced by a factor of 270, median areas for polar chemicals were only reduced by a factor of 4. Polar features showed significantly higher areas than their non-polar counterparts in wastewater treatment plant effluent and finished drinking water, implying a protection gap for these chemicals. Toxicity tests revealed higher initial toxicities (especially oxidative stress and estrogenic activity) for the non-polar fraction, but also showed a more pronounced decrease during treatment. Generally, the toxicity of the effluent was low for both fractions. Combined, these results imply a less effective removal but also a lower toxicity of polar chemicals. The behaviour of features during advanced waste and drinking water treatment was used to classify them as either PM chemicals or mobile transformation products (M-TPs). A suspect screening of the 476 highest intensity PM chemicals and M-TPs in 57 environmental and tap water samples showed high frequencies of detection (median >80%), which indicates the wide distribution of these chemicals in the aquatic environment and thus supports the chosen classification approach and the more generally applicability of obtained insights.

Rapid determination of 134 pesticides in tea through multi-functional filter cleanup followed by UPLC-QTOF-MS

Ensuring the safety of tea requires effective methods for the simultaneous analysis of pesticide residues in the product. A sensitive and reliable method to scan for 134 pesticide residues in tea was developed that employs a novel Multi-Functional Filter (MFF) based on d-SPE extraction and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The adsorption material was developed by porous polyvinylpolypyrrolidone (PVPP) for the removal of polyphenols. Acetonitrile extraction was passed through a syringe and then detected by UPLC-Q-TOF-MS. Method validation revealed satisfactory linearity with correlation coefficients higher than 0.985 for all pesticides. All limits of quantification were below 10 µg/kg. The matrix effects of 133 of the pesticides were nearly negligible (<20%), except for Sebutylazine (=22%). The recoveries at two spiked levels (50, 100 μg/kg) were 66.83-118.33%, and the Relative standard deviation (RSD) was lower than 20%, indicating accuracy and precision of the new method.

Occurrence and risk assessment of herbicides and fungicides in atmospheric particulate matter in Hanoi, Vietnam

Vietnam is a Southeast Asian developing country with rapidly increasing air pollution, especially in large cities. Over 350,000 chemicals and chemical mixtures are produced and used in Vietnam; however, the country has only implemented air quality standards for 44 substances, which are primarily focused on inorganic and volatile organic compounds. Although numerous pesticides are frequently applied across large cities in Vietnam, information on their concentrations in atmospheric particulate matter (APM) is limited. Therefore, to investigate their occurrence and health effects, 187 pesticides in APM were screened using the liquid chromatography-mass spectrometry-quadrupole time of flight- Sequential Window Acquisition of All Theoretical Fragment Ion Spectra method (LC-QTOF-MS-SWATH). A total of 22 pesticides (16 fungicides and 6 herbicides) were quantified in the dry and rainy seasons. Among them, 19 substances were quantified in APM for the first time in Vietnam. Their median total concentrations in the dry season were higher than those in the rainy season, and the concentrations in the daytime were one-third of the night-time concentrations in both seasons. Their total levels ranged from 0.82 to 21.1 ng m^-3 (median, 3.63 ng m^-3), the detection frequencies of 9 pesticides were higher than 70%, and 7-14 pesticides were detected per sample (median, 10). Some of the detected pesticides were likely sourced from their prevalent use in amenity turf protection (e.g., in parks and public roads) and weed control (e.g., in gardens, floriculture, and agriculture). The total daily intake (DI_air) values for adults, children, and infants were 8.17E-06, 2.06E-05, and 2.45E-05 mg kg^-1 d^-1, respectively, and the highest Hazard Quotients (HQs) were 4.81E-04, 1.22E-03, and 1.44E-03, respectively. All HQs and HIs of the pesticides were < 1 for all population groups (adults, children, and infants), indicating negligible exposure risks.

Environmental risk assessment and bioaccumulation of pharmaceuticals in a large urbanized estuary

We screened for the presence of 66 different pharmaceutical residues in surface waters and in multiple invertebrate and fish species of the Tejo estuary to produce an environmental risk assessment of individual pharmaceuticals and their mixtures, as well as evaluate the bioaccumulation of pharmaceuticals in one of Europe's largest estuarine systems. Sixteen pharmaceutical residues, from seven therapeutic classes, were detected in estuarine waters, with environmental mixture concentrations ranging from 42 to 1762 ng/L. Environmental risk assessment via the determination of risk quotients, demonstrated high ecological risk for the antibiotic amoxicillin and angiotensin II receptor blockers irbesartan and losartan. Moderate risk was estimated for antidepressants, antiepileptics, anxiolytics and beta-blockers, but the risk quotient of the accumulated mixture of compounds was over 380-fold higher than the no risk threshold, driven by antibiotics and angiotensin II receptor blockers. In biota, higher risk therapeutic groups were found in higher concentrations, with nine pharmaceutical residues detected, including six antibiotics and two neuroactive compounds, and maximum tissue concentrations up to 250 μg/kg. Bioaccumulation was species- and compound-specific, with only two compounds found simultaneously in water and biota, likely a result of the complex dynamics and fate of pharmaceuticals in estuarine waters. Nonetheless, higher detection frequencies were observed in species living directly on or just above the substrate (i.e. benthic and demersal species), underpinning the importance of habitat use, as well the potential role of sediment and diet based routes for pharmaceutical uptake. Ultimately, results support urgent action on managing the impact of pharmaceuticals in coastal environments, striving for improved monitoring schemes tailored to the dynamic nature and ecological diversity of estuaries and coastal ecosystems.

Screening and ecological risk of 1200 organic micropollutants in Yangtze Estuary water

The Yangtze River, the third largest river in the world, has been polluted by various organic chemicals. In 2018, China decided to implement ecological restoration of the Yangtze River to protect the river. However, except for some conventional pollution indices such as COD (Chemical Oxygen Demand) and NH₄⁺-N, the overall levels and risks of a wide variety of organic micropollutants (OMPs) in the Yangtze Estuary is not clear. Herein, results from a wide-range screening on levels and risks of OMPs in the Yangtze Estuary water were reported. 36 water samples were collected at 9 sites in the Yangtze Estuary in 2012 and 2013. Approximately 1200 OMPs were screened. A total of 131 OMPs were detected with total concentrations ranging from 1.8×10³ to 9.7×10³ ng/L. A tiered strategy was proposed to simplify the assessment of multi-substance ecological risks. Results showed that risk quotient (RQ) for 77% of the OMPs was less than 0.1. For 20 OMPs with RQ ≥ 0.1, joint probabilistic risks were assessed by species sensitivity distribution models. The joint risks as expressed by multi-substance potentially affected fractions are > 5%, and are not insignificant. The results may serve as a benchmark for protecting biodiversity in the Yangtze Estuary, as China motivated to have a fundamental improvement on the environmental quality by 2035.

Use of comprehensive target analysis for determination of contaminants of emerging concern in a sediment core collected from Beppu Bay, Japan

In recent years, concern about the release of anthropogenic organic micropollutants referred to as contaminants of emerging concern (CECs) has been growing. The objective of this study was to find potential CECs by means of an analytical screening method referred to as comprehensive target analysis with an automated identification and quantification system (CTA-AIQS), which uses gas and liquid chromatography combined with mass spectrometry (GC-MS and LC-QTOF-MS). We used CTA-AIQS to analyze samples from a sediment core collected in Beppu Bay, Japan. With this method, we detected 80 compounds in the samples and CTA-AIQA could work to useful tool to find CECs in environmental media. Among the detected chemicals, three PAHs (anthracene, chrysene, and fluoranthene) and tris(isopropylphenyl)phosphate (TIPPP) isomers were found to increase in concentration with decreasing sediment depth. We quantified TIPPP isomers in the samples by means of targeted analysis using LC-MS/MS for confirmation. The concentration profiles, combined with previous reports indicating persistent, bioaccumulative, and toxic properties, suggest that these chemicals can be categorized as potential CECs in marine environments.

Comprehensive study of insecticides in atmospheric particulate matter in Hanoi, Vietnam: Occurrences and human risk assessment

Air pollution is the most serious environmental issue in Vietnam, particularly in big cities. Air pollutants that are set as environmental standards are regularly monitored by the public institutions. Whereas, environmental data on organic micro-pollutants in atmospheric particulate matters (APMs) is limited, including PAHs and POPs. Although massive pesticides are used in big cities, their data in APMs in Vietnam is very scarce. In order to elucidate their occurrence in the ambient air in Hanoi and their health effects, we surveyed 107 insecticides in APMs by a novel target screening method using LC-QTOF-MS-SWATH. A total of 19 insecticides were detected in the dry and the rainy seasons. Among them, 16 substances are, to our knowledge, reported for the first time in the literature. Their total concentrations varied from 0.47 to 27.0 ng m^-3 (median, 3.6 ng m^-3), detection frequencies of 12 compounds are higher than 42%, and the number of insecticides detected per each sample ranging from 5 to 13 (median, 9). Total concentrations in the dry season were generally higher than in the rainy season, and concentrations at night were higher than daytime in both seasons. The level of insecticides depends not only on the season, but also on its physicochemical properties, its application conditions, and the meteorological conditions. Their emission sources could be related to agricultural usage, floricultural activities, and pest control in houses. The total maximum daily intake (DI_air) through inhalation for adults and children were 2.39E-05 mg kg^-1 d^-1 and 2.98E-05 mg kg^-1 d^-1, respectively. The highest Hazard Quotients (HQs) were 1.34E-03 and 3.37E-03, and the highest Hazard Indices (HIs) were 2.71E-03 and 6.33E-03 for adults and children, respectively. All values of HQs, and HIs of insecticides were less than 1, indicating that health risk would be negligible.

Development of a rapid and comprehensive method for identifying organic micropollutants with high ecological risk to the aquatic environment

Currently, tens-of-thousands of chemicals are used in Japan, and their presence in and impact on aquatic ecosystems are poorly understood. Because conventional risk evaluation processes using target analysis and biological tests are time-consuming and costly, it is challenging to investigate all substances. Therefore, we aimed to develop a rapid and highly efficient screening scheme for identifying hazardous organic micropollutants (OMPs) in aquatic ecosystems. The scheme is divided into two steps: chemical analysis and risk evaluation. First, a comprehensive screening method (CSM) using gas chromatography (GC)-mass spectrometry (MS) and a database containing nearly 1000 compounds is used to identify known compounds, and nontargeted analysis is carried out using a GC × GC-time-of-flight (TOF)MS to detect compounds not registered in the database. Secondly, the predicted toxicity values obtained by quantitative structure-activity relationship (QSAR) are used to evaluate and rank the ecological risk of each detected OMPs and to identify priority compounds for detailed survey. To assess the proposed scheme, we surveyed representative urban rivers in Japan and ranked the potential toxicity of the identified compounds. The total number of compounds detected in water from each river ranged from 29 to 87, and the total concentrations ranged from 2.3 to 63 μg L^-1. Pharmaceuticals and personal care products, such as crotamiton and galaxolide, were identified in the urban rivers and found to have high ecotoxicity rankings. Thus, the scheme combining CSM and risk evaluation using QSAR is a novel screening that can identify candidates with high ecological risk in aquatic environment rapidly and efficiently.

Customized dispersive micro-solid-phase extraction device combined with micro-desorption for the simultaneous determination of 39 multiclass pesticides in environmental water samples

A dispersive micro-solid phase extraction (d-µ-SPE) procedure was developed for the simultaneous extraction of 39 multiclass pesticides, containing a variety of chemical groups (organophosphate, organochlorine, pyrethroid, strobilurin, thiocarbamate, triazole, imidazole, and triazine), from water samples. A customized d-µ-SPE glass device was combined with a multi-tube platform vortex and a micro-desorption unit (Whatman Mini-UniPrep G2 syringeless filter), which allowed the unique simultaneous desorption, extract filtration, and injection. A simplex-centroid mixture design and Doehlert design were employed to optimize the extraction conditions. The optimized extraction conditions consisted of an extraction time of 30 min, an addition of 6.74 % of NaCl into 100 mL of water sample, and a desorption time of 24 min with 500 µL of EtAc. The procedure provided a low limit of detection (LOD), ranging from 0.51 ng L^-1 (4,4-DDE) to 22.4 ng L^-1 (dimethoate), and an enrichment factor ranging from 72.5 (dimethoate) to 200 (tebuconazole). The relative recoveries of the pesticides from spiked freshwater and seawater ranged from 74.2 % (endrin) to 123 % (molinate). The proposed procedure was applied to detect the presence of multiclass pesticides in environmental water samples. Three pesticides commonly applied in Brazil, namely, malathion, dimethoate, and lambda-cyhalothrin, were detected in concentrations ranging from <LOD to 120 ng L^-1 (dimethoate).

Simultaneous screening for chemically diverse micropollutants in public water bodies in Japan by high-performance liquid chromatography-Orbitrap mass spectrometry

An improved assessment of environmental risks to public water bodies requires screening a large number of micropollutants. This study reports the development of a novel target screening method based on solid-phase extraction (SPE), HPLC, and high-resolution Orbitrap MS for the analysis of micropollutants with diverse chemical properties. First, target compounds were screened for their detectability by Orbitrap MS. An optimized SPE cartridge and HPLC column maximized recovery and separated most target compounds. The sensitivity and repeatability of the method was validated by determining the detection limits and relative standard deviation (RSD). Eighty-four compounds with highly diverse properties were simultaneously detected with detection limits of 0.1-100 ng/L. Of these compounds, 52 were quantitated, with R2 ≥ 0.99 by linearity analysis and SPE recovery ratios of ≥50%. The remaining 32 compounds were qualitatively detected, with R2 < 0.99 or SPE recovery ratio of <50%. Satisfactory repeatability was obtained (RSD < 13.5%). This method was applied to the surveillance of the Arakawa River in Japan in 2019. Thirty-two compounds, including pesticides, surfactants, plasticizers, adhesives, and industrial solvents, were detected in the river. The measured concentrations of 13 compounds were compared with their predicted no effect concentrations (PNECs). Decanoic acid showed a higher concentration than the corresponding PNEC value, suggesting that its risk to the Arakawa water environment required further evaluation. The concentrations of dicyclohexylamine, 1,3-diphenylguanidine, and 2,4-dichlorophenoxyacetic acid were higher than their corresponding PNEC/10 values, demonstrating that these compounds were of higher priority than other compounds.

Occurrence and Health Risks of Organic Micro-Pollutants and Metals in Groundwater of Chinese Rural Areas

BACKGROUND

Groundwater is a main drinking-water source for Chinese rural residents. The overall pollution status of organic micropollutants (OMPs) and metals in the groundwater and corresponding health risks are unknown.

OBJECTIVES

Our objective was to comprehensively screen for and assess the health risks of OMPs and metals in groundwater of rural areas in China where groundwater is used for drinking so as to provide a benchmark for monitoring and improving groundwater quality in future developments.

METHODS

One hundred sixty-six groundwater samples were collected in the rural areas of China, and 1,300 OMPs and 25 metals were screened by GC-MS, LC-QTOF/MS, and ICP-MS analysis. To assess the noncarcinogenic and carcinogenic risks of the detected pollutants, missing toxicity threshold values were extrapolated from existing databases or predicted by quantitative structure-activity relationship (QSAR) models. Monte Carlo simulation was performed to account for uncertainties in the exposure parameters and toxicity thresholds.

RESULTS

Two hundred thirty-three OMPs and 25 metals were detected from the 166 samples. The concentration summation for the detected OMPs ranged from 2.9 to 1.7×105ng/L among the different sampling sites. Cumulative noncarcinogenic risks for the OMPs were estimated to be negligible. However, high metal risks were calculated in 23% of the sites. Forty-two carcinogens (including 38 OMPs) were identified and the cumulative carcinogenic risks in 34% of the sites were calculated to be >10-4 (i.e., one excess cancer case in a population of 10 thousand people). The carcinogenic risks were estimated to be mainly associated with exposures to the metals, which were calculated to contribute 79% (0-100%) of the cumulative carcinogenic risks.

DISCUSSION

The overall status of OMPs and metals pollution in the groundwater and the corresponding health risks were determined preliminarily, which may provide a benchmark for future efforts in China to ensure the safety of drinking water for the local residents in rural areas. The joint application of QSARs and Monte Carlo simulation provided a feasible way to comprehensively assess the health risks of the large and ever-increasing number of pollutants detected in the aquatic environment. https://doi.org/10.1289/EHP6483.

Trends in sample preparation and separation methods for the analysis of very polar and ionic compounds in environmental water and biota samples

Recent years showed a boost in knowledge about the presence and fate of micropollutants in the environment. Instrumental and methodological developments mainly in liquid chromatography coupled to mass spectrometry hold a large share in this success story. These techniques soon complemented gas chromatography and enabled the analysis of more polar compounds including pesticides but also household chemicals, food additives, and pharmaceuticals often present as traces in surface waters. In parallel, sample preparation techniques evolved to extract and enrich these compounds from biota and water samples. This review article looks at very polar and ionic compounds using the criterion log P ≤ 1. Considering about 240 compounds, we show that (simulated) log D values are often even lower than the corresponding log P values due to ionization of the compounds at our reference pH of 7.4. High polarity and charge are still challenging characteristics in the analysis of micropollutants and these compounds are hardly covered in current monitoring strategies of water samples. The situation is even more challenging in biota analysis given the large number of matrix constituents with similar properties. Currently, a large number of sample preparation and separation approaches are developed to meet the challenges of the analysis of very polar and ionic compounds. In addition to reviewing them, we discuss some trends: for sample preparation, preconcentration and purification efforts by SPE will continue, possibly using upcoming mixed-mode stationary phases and mixed beds in order to increase comprehensiveness in monitoring applications. For biota analysis, miniaturization and parallelization are aspects of future research. For ionic or ionizable compounds, we see electromembrane extraction as a method of choice with a high potential to increase throughput by automation. For separation, predominantly coupled to mass spectrometry, hydrophilic interaction liquid chromatography applications will increase as the polarity range ideally complements reversed phase liquid chromatography, and instrumentation and expertise are available in most laboratories. Two-dimensional applications have not yet reached maturity in liquid-phase separations to be applied in higher throughput. Possibly, the development and commercial availability of mixed-mode stationary phases make 2D applications obsolete in semi-targeted applications. An interesting alternative will enter routine analysis soon: supercritical fluid chromatography demonstrated an impressive analyte coverage but also the possibility to tailor selectivity for targeted approaches. For ionic and ionizable micropollutants, ion chromatography and capillary electrophoresis are amenable but may be used only for specialized applications such as the analysis of halogenated acids when aspects like desalting and preconcentration are solved and the key advantages are fully elaborated by further research. Graphical abstract.

Occurrences of microorganic pollutants in the Kumho River by a comprehensive target analysis using LC-Q/TOF-MS with sequential window acquisition of all theoretical fragment ion spectra (SWATH)

In this study, simultaneous identification and semi-quantification of hundreds of micropollutant compounds, including pharmaceutical and personal care products (PPCPs) and pesticides were performed in river and effluent samples from the Kumho River Basin using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) with sequential window acquisition of all theoretical fragment ion spectra (SWATH). In total, 85 compounds (29 pesticides and 56 PPCPs) were identified. The highest proportions of PPCP residues were detected in the downstream area of the Kumho River, close to the central city. On the other hand, the highest proportions of pesticide residues were observed upstream, near agricultural land and golf courses. Additionally, the highly exposable chemicals were prioritized using a scoring and ranking system based on their concentration and detection frequency. Thus, 20 compounds (7 pesticides and 13 PPCPs) with scores of 200 or higher were defined as highly exposable compounds in Kumho River basin.

Analysis of mobile chemicals in the aquatic environment-current capabilities, limitations and future perspectives

Persistent and mobile water contaminants are rapidly developing into a focal point of environmental chemistry and chemical regulation. Their defining parameter that sets them apart from the majority of regularly monitored and regulated contaminants is their mobility in the aquatic environment, which is intrinsically tied to a high polarity. This high polarity, however, may have severe implications in the analytical process and thus the most polar of these mobile contaminants may not be covered by widely utilized trace-analytical methods, and thus, alternatives are required. In this review, we infer the physical and chemical properties of mobile water contaminants from a set of almost 1800 prioritized REACH chemicals and discuss the implications these substance properties may have on four integral steps of the analytical process: sampling and sample storage, sample pre-treatment, separation and detection. We discuss alternatives to widely utilized trace-analytical methods, examine their application range and limitations, highlight potential analytical techniques on the horizon and emphasize research areas we believe still offer the most room for further improvement. While we have a comprehensive set of analytical methods to cover a large portion of the known mobile chemicals, these methods are still only infrequently utilized. Graphical abstract.

Comprehensive Target Analysis for 484 Organic Micropollutants in Environmental Waters by the Combination of Tandem Solid-Phase Extraction and Quadrupole Time-of-Flight Mass Spectrometry with Sequential Window Acquisition of All Theoretical Fragment-Ion Spectra Acquisition

There are many thousands of chemicals in use for a wide range of purposes, and highly efficient analytical methods are required to monitor them for protection of the environment. In order to cope with this difficult task we developed a novel, comprehensive method for 484 substances in water samples. In this method target chemicals were extracted by tandem SPE and then determined by LC-QTOF-MS-SWATH. Targets were unambiguously identified using retention times, accurate masses of a precursor and two product ions, their ion ratios, and accurate MS/MS spectrum. Quantitation was achieved by the internal standard method using a precursor ion. Results of recovery tests at two concentrations (50 and 500 ng L^-1) showed average recoveries of 87.5% and 87.0% (RSD, 9.1% and 9.4%), respectively. Limits of detection of one-half of the targets were below 1.0 ng L^-1. The method was applied to the influent and effluent of a sewage treatment plant, and around 100 chemicals were detected. Results of examination on matrix effects using their extracts spiked with 209 pesticides showed that the ratios of detected amounts between the extracts and the standard solution were 89.8% (influent) and 91.7% (effluent), respectively. In addition, investigation on the stability of calibration curves by injecting the same standards for 1 year showed that their quantitative results did not change; average accuracy was 103.3% (RSD, 10.0%), indicating that the calibration curves can be used for an extended period of time without calibration, and quantitative retrospective analysis can be done after creating calibration curves for new targets.

Development of a novel scheme for rapid screening for environmental micropollutants in emergency situations (REPE) and its application for comprehensive analysis of tsunami sediments deposited by the great east Japan earthquake

The tsunami triggered by the Great East Japan Earthquake of March 2011, the strongest quake ever recorded in Japan, deposited tsunami sediments along the coastline of the affected area. Because the sediments contained a wide variety of hazardous chemicals, including organic micropollutants, a method for rapidly evaluating the environmental and human health risks of such chemicals is necessary. For this purpose, we propose a novel three-step scheme designated "rapid screening for environmental micropollutants in emergency situations (REPE)". In the first step, samples are subjected to target screening analysis using an automated identification and quantification system (TSA-AIQS) involving gas chromatography mass spectrometry (GC-MS). In the second step, the chemicals detected by TSA-AIQS analysis are quantified precisely by conventional target analysis. The third step is risk assessment of the target chemicals. TSA-AIQS analysis of the tsunami sediments detected 63 substances, including polycyclic aromatic hydrocarbons (both native and alkylated PAHs) at high concentrations. These PAHs were precisely quantified by target analysis, and the concentrations were used to assess the health risks posed by oral intake, which were found to be negligible. Our results suggest that the REPE scheme will be useful for rapid, comprehensive screening and risk assessment in emergency situations.

Quorum sensing between Gram-negative bacteria responsible for methane production in a complex waste sewage sludge consortium

Quorum sensing (QS) plays a key role in activating bacterial functions through small molecules called autoinducers. In this study, the QS of Gram-negative bacteria in waste sewage sludge (WSS) was downregulated by adding the quorum quenching enzyme, AiiM lactonase, which cleaved the acyl-homoserine lactone (AHL) autoinducer signals from Gram-negative bacteria, and subsequently methane production was inhibited by over 400%. The pH was lowered after 2 days in the anaerobic fermentation whereas protease activity at the hydrolysis step was almost the same with or without AiiM. The production of acetic acid significantly increased during the fermentation in the presence of AiiM. The bacterial community at day 2 indicated that the population of Gram-positive bacteria increased in the presence of AiiM, and the percentage of Gram-negative bacteria decreased in the WSS containing AiiM. The change in the bacterial community in the presence of AiiM may be due to the different antimicrobial agents produced in the WSS because some of the Gram-positive bacteria were killed by adding the solid-phase extraction (SPE) fraction from the WSS without AiiM. In contrast, the SPE fraction with AiiM had reduced bactericidal activity against Gram-negative bacteria. Thus, bacterial signaling between Gram-negative bacteria is critical for methane production by the microbial consortia.

Screening of human and veterinary pharmaceuticals in estuarine waters: A baseline assessment for the Tejo estuary

We investigated the presence of 66 human and veterinary pharmaceuticals from seven therapeutic groups in surface waters of the Tejo estuary. Collection sites covered the entire estuary and included areas near main river inflows and wastewater treatment outfalls, traversing urban, agriculture, aquaculture, and nature reserve areas. Detection of pharmaceuticals was performed via UHPLC-TOF-MS. Pharmaceuticals were found in all sites (32 different compounds in total). Antibiotics, β-blockers, antihypertensives and anti-inflammatories were the most frequently detected (>90%), with variation in concentrations reflecting the multifaceted nature of estuarine surroundings (accumulated site contamination between 15 and 351 ng L^-1). Higher concentrations of antidepressant Sertraline (304 ng L^-1), non-steroidal anti-inflammatory Diclofenac (51.8 ng L^-1), lipid regulator Gemfibrozil (77.0 ng L^-1), antihypertensive Ibersartan (161.9 ng L^-1) or antibiotic Doxycycline (128.0 ng L^-1), among others, though localized may potentially impact key estuarine functions or services. Ultimately, results provide a baseline for regulatory information and future biota evaluations.