Spatio-temporal variation and ecological risk assessment of microplastics along the touristic beaches of a mediterranean coast transect (Valencia province, East Spain).

Annually, the Mediterranean region attracts around one-third of the global coastal tourism, which is acknowledged as a substantial contributor to plastic pollution. Coastal municipalities mitigate this through periodic sand and shore cleaning. However, the efficacy of these measures remains uncertain. In this study, the occurrence of MPs (10 µm-5 mm) in sand from seven different, regularly cleaned, touristic beaches of the coastline of Valencia province (E Spain) was assessed. Two different sampling campaigns were performed in winter and in summer (2022) to compare the results and understand the influence of the high touristic activity, as well as, the efficiency of the measures taken against MPs pollution. The methodology used was designed specifically for the matrix and employed density separation using a Sediment Microplastic Isolation (SMI) Unit. In addition to conventional visual inspection and ATR-FTIR, automatic quantification and identification of the polymers of lower size was performed by µFTIR. The average MPs concentration in the summer (339 ± 92 MP kg-1 by stereomicroscopy and 339 ± 189 MP kg-1 by µFTIR) was significantly higher than in the winter (71 ± 92 MP kg-1 and 143 ± 85 MP kg-1) (p < 0.05). The combination of these analytical tools provides comprehensive information about the MPs present in beach sand. Fibers were the most abundant form of MPs, while most of the polymers analyzed were polyethylene (PE) and halogenated polystyrene (Cl-PS and Br-PS) with food packaging, swimming equipment and fishing nets being their most probable sources. Ecological risk assessment was performed through the Pollution Load Index (PLI), the Hazardous Index (HI) and the Risk Quotient (RQ), with the results indicating potential risk that ranges from moderate to high depending on the applied approach.

An effective method for the simultaneous extraction of 173 contaminants of emerging concern in freshwater invasive species and its application.

A robust and efficient extraction method was developed to detect a broad range of pollutants of emerging interest in three freshwater invasive species: American red crab (Prokambarus clarkii), Asian clam (Corbicula fluminea), and pumpkinseed fish (Lepomis gibbosus). One native species, "petxinot" clam (Anodonta cygnea), was also evaluated. Invasive species are often more resistant to contamination and could be used in biomonitoring studies to assess the effect of contaminants of emerging concern on aquatic ecosystems while preserving potentially threatened native species. So far, most extraction methods developed for this purpose have focused on analyzing fish and generally focus on a limited number of compounds, especially analyzing compounds from the same family. In this sense, we set out to optimize a method that would allow the simultaneous extraction of 87 PhACs, 11 flame retardants, 21 per- and poly-fluoroalkyl substances, and 54 pesticides. The optimized method is based on ultrasound-assisted solvent extraction. Two tests were performed during method development, one to choose the extraction solvent with the best recovery efficiencies and one to select the best clean-up. The analysis was performed by high-performance liquid chromatography coupled to high-resolution mass spectrometry. The method obtained recoveries between 40 and 120% and relative standard deviations of less than 25% for 85% of the analytes in the four validated matrices. Limits of quantification between 0.01 ng g-1 and 22 ng g-1 were obtained. Application of the method on real samples from the Albufera Natural Park of Valencia (Spain) confirmed the presence of contaminants of emerging concern in all samples, such as acetaminophen, hydrochlorothiazide, tramadol, PFOS, carbendazim, and fenthion. PFAS were the group of compounds with the highest mean concentrations. C. fluminea was the species with the highest detection frequency, and P. clarkii had the highest average concentrations, so its use is prioritized for biomonitoring studies.

Prediction Models Based on Soil Characteristics for Evaluation of the Accumulation Capacity of Nine Metals by Forage Sorghum Grown in Agricultural Soils Treated with Varying Amounts of Poultry Manure.

Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40 g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF) < 1 was calculated for Cr, Fe, Ni, Pb and Zn; BAF values for Co, Cu, Mn and Cd were 3.99, 2.33, 1.44 and 1.40, respectively, i.e., > 1. Translocation factor values were < 1 for all metals with the exception of Co, Cr and Ni, which displayed values of 1.20, 1.67 and 1.35 for the leaves, and 1.12, 1.23 and 1.24, respectively, for the stems. The soil pH had a negative association with metal tissues in plant parts. A positive relationship was observed with respect to plant metal contents, electrical conductivity and organic matter quantity. The designed models exhibited a high standard of data precision; any variations between the predicted and experimentally observed contents for the nine metals in the three plant tissue components were nonsignificant. Thus, it was concluded that the presented predictive models constitute a pragmatic tool to establish the safety from risk to human well-being with respect to growing forage sorghum when cultivating media fortified with poultry manure.

Neonicotinoids in excretion product of phloem-feeding insects kill beneficial insects.

Pest control in agriculture is mainly based on the application of insecticides, which may impact nontarget beneficial organisms leading to undesirable ecological effects. Neonicotinoids are among the most widely used insecticides. However, they have important negative side effects, especially for pollinators and other beneficial insects feeding on nectar. Here, we identify a more accessible exposure route: Neonicotinoids reach and kill beneficial insects that feed on the most abundant carbohydrate source for insects in agroecosystems, honeydew. Honeydew is the excretion product of phloem-feeding hemipteran insects such as aphids, mealybugs, whiteflies, and psyllids. We allowed parasitic wasps and pollinating hoverflies to feed on honeydew from hemipterans feeding on trees treated with thiamethoxam or imidacloprid, the most commonly used neonicotinoids. LC-MS/MS analyses demonstrated that both neonicotinoids were present in honeydew. Honeydew with thiamethoxam was highly toxic to both species of beneficial insects, and honeydew with imidacloprid was moderately toxic to hoverflies. Collectively, our data provide strong evidence for honeydew as a route of insecticide exposure that may cause acute or chronic deleterious effects on nontarget organisms. This route should be considered in future environmental risk assessments of neonicotinoid applications.

Suspected-screening assessment of the occurrence of organic compounds in sewage sludge.

The profiling of emerging organic pollutants present in sludge and generated during wastewater treatment is much more limited than in water. This is mainly due to the difficulty of sludge analysis because of its high content of organic matter and interfering compounds. In this study, a generic extraction method using a mixture of buffered water (pH 4.1) and solid phase extraction (SPE) clean-up was applied to samples of sludge obtained in different treatment plants. This extraction was followed by determination of the contaminants by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS), using suspected screening to detect the most relevant organic compounds that access the environment through sludge application. This screening (including >3000 substances, such as, pharmaceuticals, pesticides, metabolites and industrial chemicals) tentatively identified 122 compound and assigned most probable structure to 39. The set of compounds assigned to a probable structure was increased in 14 compounds by searching in a free database of metabolites. Fifteen compounds were unequivocally confirmed against the analytical standard. Pharmaceuticals and personal care products (PPCPs), with 31 substances identified and 8 confirmed were the main group of compounds. Compounds frequently detected in all sludge samples include nucleotides such as adenosine triphosphate, amino acids such as phenylalanine, or peptides such as leu-phe. Altogether, the results of this work highlight the interest of HRMS to draw the profile of organic compounds in complex matrices.

Identification of biomarkers in wastewater-based epidemiology: Main approaches and analytical methods.

Wastewater-based epidemiology (WBE) has become popular to estimate the use of drugs of abuse and recently to establish the incidence of CoVID 19 in large cities. However, its possibilities have been expanded recently as a technique that allows to establish a fingerprint of the characteristics of a city, such as state of health/disease, healthy/unhealthy living habits, exposure to different types of contaminants, etc. with respect to other cities. This has been thanks to the identification of human biomarkers as well as to the fingerprinting and profiling of the characteristics of the wastewater catchment that determine these circumstances. The purpose of this review is to analyze the different methodological schemes that have been developed to perform this biomarker identification as well as the most characteristic analytical techniques in each scheme, their advantages and disadvantages and the knowledge gaps identified. We also discussed the future scope for development.

Postflood Monitoring in a Subtropical Estuary and Benchmarking with PFASs Allows Measurement of Chemical Persistence on the Scale of Months.

Measurements of chemical persistence in natural environments can provide insight into behavior not easily replicated in laboratory studies. However, it is difficult to find environmental situations suitable for such measurements, particularly for substances with half-lives exceeding several weeks. The objective of this study was to demonstrate that a strategic postflood monitoring campaign can be used to quantify transformation half-lives on the scale of months in a real aquatic system. Water samples were collected in the upper Brisbane River estuary on 36 occasions over 37 weeks and analyzed for 127 pharmaceuticals and personal care products (PPCPs), pesticides, and perfluoroalkyl substances (PFASs). High quality time trend data were obtained for 41 substances. For many of these, data on the input of a wastewater treatment plant to the upper estuary were also obtained. A mass balance model of the estuary stretch was formulated and parametrized using PFASs as persistent benchmarking chemicals. Transformation half-life estimates were obtained for 10 PPCPs and 7 pesticides ranging from 18 to 260 days. Furthermore, insight was obtained into dominant transformation processes as well as the magnitude of chemical inputs to the estuary and their sources. The approach developed shows that under certain conditions, estuaries can be used to quantify the persistence of organic contaminants with half-lives of the order of several months.

Development of multi-residue extraction procedures using QuEChERS and liquid chromatography tandem mass spectrometry for the determination of different types of organic pollutants in mussel.

This study aimed to develop multi-residue methods for the extraction of organic pollutants in mussels (Mytilus galloprovincialis), including 11 pharmaceuticals, 5 pesticides, 5 perfluoroalkyl substances (PFASs) and 2 illicit drugs. The combination of 4 different QuEChERS methods and 12 clean-ups (a total of 44 combinations) was tested. QuEChERS included acidified (AQ), non-acidified (SQ) and their miniaturized versions. The clean-ups included 6 different conventional dispersive solid phase extraction (dSPE) plus 2 enhanced matrix removal (EMR-Lipid) and 4 SPE procedures (including sorbents focused on phospholipid removal and polymer-based). After sample analysis via HPLC-MS/MS, the three methods that provided the best results were validated in terms of linearity, accuracy, precision, sensitivity and matrix effect. The methods selected were the combination of (i) SQ and EMR-Lipid, (ii) AQ and Z-sep+ bulk-based dSPE and (iii) AQ and graphitized carbon black (GCB)-based dSPE. Recoveries at two concentration levels (50 and 500 ng/g) ranged 54-124%, 59-124% and 60-127%, respectively, and limits of quantification (LOQs) were < 30 ng/g for most analytes using any of the methods. The three methods were tested in non-spiked mussel samples purchased in local markets, but organic pollutants were not detected in any sample. However, the methods probed to successfully extract a wide range of organic pollutants families in mussel samples from the market and from bioaccumulation trials.

Multi-residue extraction to determine organic pollutants in mussel hemolymph.

This study assesses the extraction of eleven pharmaceuticals, five pesticides, five perfluoroalkyl substances, and two illicit drugs in hemolymph from (Mytilus Galloprovincialis). Four extraction procedures using Phree™ Phospholipid Removal cartridges were tested using different volumes of methanol (400 and 600 µL) and acetonitrile (300 and 450 µL). The pollutants were determined by high-performance liquid chromatography-tandem mass spectrometry. The use of methanol gave several problems during the extraction procedure, such as longer times and sample loss. Three methods (acetonitrile 300 and 450 µL; and methanol 600 µL) were validated. Recoveries at three concentration levels (5, 50, and 100 ng/mL) ranged 35.1-129.0 and 29.3-133.0% for acetonitrile 300 and 450 µL, respectively, while recoveries for methanol 600 µL ranged 52.2-166.0%. Limits of detection were < 10 ng/mL for most analytes using any of the methods. Methanol 600 µL was the only method capable to extract the illicit drug 4-methoxyphencyclidine and provided a better peak shape and higher signal-noise ratio. When applied to non-spiked samples from local markets salicylic acid and diclofenac were detected at 33.50-97.79 and 28.30-30.31 ng/mL respectively. To our knowledge, there are no methods to determine organic contaminants in hemolymph and this is the first application of Phree™ cartridges for mussel hemolymph extraction.

Non-Occupational Exposure to Pesticides: Experimental Approaches and Analytical Techniques (from 2019).

BACKGROUND: Pesticide residues are a threat to the health of the global population, not only to farmers, applicators, and other pesticide professionals. Humans are exposed through various routes such as food, skin, and inhalation. This study summarizes the different methods to assess and/or estimate human exposure to pesticide residues of the global population. METHODS: A systematic search was carried out on Scopus and web of science databases of studies on human exposure to pesticide residues since 2019. RESULTS: The methods to estimate human health risk can be categorized as direct (determining the exposure through specific biomarkers in human matrices) or indirect (determining the levels in the environment and food and estimating the occurrence). The role that analytical techniques play was analyzed. In both cases, the application of generic solvent extraction and solid-phase extraction (SPE) clean-up, followed by liquid or gas chromatography coupled to mass spectrometry, is decisive. Advances within the analytical techniques have played an unquestionable role. CONCLUSIONS: All these studies have contributed to an important advance in the knowledge of analytical techniques for the detection of pesticide levels and the subsequent assessment of nonoccupational human exposure.

Application of a Low Transition Temperature Mixture for the Dispersive Liquid-Liquid Microextraction of Illicit Drugs from Urine Samples.

The use of psychoactive substances is a serious problem in today's society and reliable methods of analysis are necessary to confirm their occurrence in biological matrices. In this work, a green sample preparation technique prior to HPLC-MS analysis was successfully applied to the extraction of 14 illicit drugs from urine samples. The isolation procedure was a dispersive liquid-liquid microextraction based on the use of a low transition temperature mixture (LTTM), composed of choline chloride and sesamol in a molar ratio 1:3 as the extracting solvent. This mixture was classified as LTTM after a thorough investigation carried out by FTIR and DSC, which recorded a glass transition temperature at -71 °C. The extraction procedure was optimized and validated according to the main Food and Drug Administration (FDA) guidelines for bioanalytical methods, obtaining good figures of merit for all parameters: the estimated lower limit of quantitation (LLOQ) values were between 0.01 µg L-1 (bk-MMBDB) and 0.37 µg L-1 (PMA); recoveries, evaluated at very low spike levels (in the ng-µg L-1 range), spanned from 55% (MBDB) to 100% (bk-MMBDB and MDPV); finally, both within-run and between-run precisions were lower than 20% (LLOQ) and 15% (10xLLOQ).

Systematic assessment of extraction of pharmaceuticals and personal care products in water and sediment followed by liquid chromatography-tandem mass spectrometry.

Two solid-phase extraction methods were systematically studied to determine 32 pharmaceuticals and personal care products in water and sediments by ultrahigh-performance liquid chromatography-tandem mass spectrometry. One involves HLB cartridges activated with sodium dodecyl sulfate before the passage of the sample to form an ion pair with cationic analytes, and the other uses mixed HLB-cation exchange cartridges. The accuracy of the sodium dodecyl sulfate method was good for most compounds (recoveries of 61-120% with relative standard deviation less than 23%). However, the recoveries for atorvastatin, codeine, paracetamol, flufenamic acid, and salicylic acid were approximately 50% and for omeprazole and triclocarban were even lower (from 0 to 12%). The detection limits were 1.65-25 ng L-1 in water and 0.33-4.00 ng g-1 (dry weight) in sediment. The recoveries for the mixed-mode cartridge (Strata-X-CW) method ranged from 57% to 120% with relative standard deviation less than 21%, with the exception of codeine [25% (water)], metformin [11% (sediment)], paracetamol [48% (sediment)], and salicylic acid [32% (sediment)]. The detection limits were 1.65-38.35 ng L-1 in water and 0.33-10 ng g-1 (dry weight) in sediment. Both methods followed the same pattern when applied to water. For sediments, the recoveries, which offer good performance, were not very high, although 60% of the compounds had recoveries greater 80%. The methods were applied to the analysis of surface water and sediments from the Albufera Natural Park (Spain). Twenty-seven of 32 analytes were detected in the samples analyzed.

Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction.

Pharmaceuticals and personal care products (PPCPs) are abundantly used by people, and some of them are excreted unaltered or as metabolites through urine, with the sewage being the most important source to their release to the environment. These compounds are in almost all types of water (wastewater, surface water, groundwater, etc.) at concentrations ranging from ng/L to µg/L. The isolation and concentration of the PPCPs from water achieves the appropriate sensitivity. This step is mostly based on solid-phase extraction (SPE) but also includes other approaches (dispersive liquid-liquid microextraction (DLLME), buckypaper, SPE using multicartridges, etc.). In this review article, we aim to discuss the procedures employed to extract PPCPs from any type of water sample prior to their determination via an instrumental analytical technique. Furthermore, we put forward not only the merits of the different methods available but also a number of inconsistencies, divergences, weaknesses and disadvantages of the procedures found in literature, as well as the systems proposed to overcome them and to improve the methodology. Environmental applications of the developed techniques are also discussed. The pressing need for new analytical innovations, emerging trends and future prospects was also considered.

Effect of the conversion of mangroves into shrimp farms on carbon stock in the sediment along the southern Red Sea coast, Saudi Arabia.

The conservation of coastal ecosystems and specially mangroves ''blue carbon'' is receiving more attention as consequence of their recognition as high ecosystem carbon stocks and for the fact that these areas are undergoing land conversion. The aim of the present study is to evaluate the impact of land use changes due to conversion of mangroves to shrimp farms on the bulk density (SBD), organic carbon (SOC) concentration, and SOC stock in the sediments along the southern Saudi Arabian Red Sea coast. Shrimp farms and mangrove locations showed significant (P < 0.001) differences in SBD with high mean values in the sediments of shrimp farms. Shrimp farms and mangrove locations showed significant (P < 0.001) SOC concentration differences with high mean values in the sediments of mangroves. Considering the whole depth of sediment interval (0-100 cm), the highest value of SOC stock was recorded at mangroves (29.2 kg C m-2) and the lowest was identified at the locations of shrimp farms (19.9 kg C m-2). The results show that SOC stock of mangroves is 147% higher than that of shrimp farms confirming the fact that anthropogenic factors contributed significantly to SOC stock decrease. The mean cumulative potential carbon dioxide (CO2) emission due to loss soil carbon stock from mangrove conversion to the shrimp ponds was 34.9 kg CO2 m-2. In conclusion, the conversion of mangroves into shrimp farms contributed to the loss of SOC stock, therefore, the preservation of mangrove areas has an important value especially in arid areas such as Saudi Arabia.

Analysis of ibuprofen and its main metabolites in roots, shoots, and seeds of cowpea (Vigna unguiculata L. Walp) using liquid chromatography-quadrupole time-of-flight mass spectrometry: uptake, metabolism, and translocation.

A liquid chromatography quadruple time-of-flight mass spectrometry (LC-QqTOF-MS/MS) method was developed for simultaneous quantitative analysis of ibuprofen (IBU), 1- and 2-hydroxyibuprofen (1-OH IBU and 2-OH IBU), and carboxyibuprofen (CBX IBU) while preserving the ability of the instrument to get precursor and product ion mass spectra of non-target compounds. The trigger was the precursor ions reaching 100 cps intensity. Sample preparation was carried out by ultrasound solid-liquid extraction with methanol as extraction solvent at pH < 2 followed by solid-phase extraction (SPE) clean-up using STRATA-X cartridges and methanol as an eluent. Linearity was obtained in the range 50-10,000 ng mL-1 for IBU, each OH IBU and CBX IBU (r ≥ 0.99). The proposed method was satisfactorily validated showing absolute recoveries of > 70% for all target analytes at low and high concentration levels. The lowest limit of quantification was < 50 ng g-1 in plant. This method was applied to investigate IBP behavior in cowpea (Vigna unguiculata (L.) Walp) treated at high IBU concentrations and its presence in vegetables irrigated with treated water. Up to 46 metabolites, mostly hydroxylated metabolites and conjugates with hexosides and amino acids, were identified. The most abundant metabolites were also identified in an eggplant sample. Graphical Abstract ᅟ Ibuprofen metabolite identification.

Determination of organophosphate flame retardants in soil and fish using ultrasound-assisted extraction, solid-phase clean-up, and liquid chromatography with tandem mass spectrometry.

A solid-liquid extraction method in combination with high-performance liquid chromatography and tandem mass spectrometry was developed and optimized for extraction and analysis of organophosphorus flame retardants in soil and fish. Methanol was chosen as the optimum extraction solvent, not only in terms of extraction efficiency, but also for its broader analyte coverage. The subsequent clean-up by solid-phase extraction is required to eliminate matrix coextractives and reduce matrix effects. Recoveries of the optimized method were 50-121% for soil and 47-123% for biota, both with high precision (RSDs <12% in soil and <23% in biota). The method limits of detection ranged from 0.06 to 0.20 ng/g dry weight and between 0.02 and 0.30 ng/g wet weight for soil and biota samples, respectively. However, samples with a high lipid content produce several problems as solid-phase extraction cartridge clogging that increase variability and analysis time. The method was successfully applied for the determination of organophosphorus flame retardants in soil and fish from L'Albufera Natural Park (Valencia, Spain). Target compounds were detected in all soil and fish samples with values varying from 13.8 to 89.7 ng/g dry weight and from 3.3 to 53.0 ng/g wet weight, respectively.

Simultaneous determination of pyrethroids and pyrethrins by dispersive liquid-liquid microextraction and liquid chromatography triple quadrupole mass spectrometry in environmental samples.

A simple and environmentally friendly dispersive liquid-liquid microextraction (DLLME) method coupled with electrospray ionization liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS/MS) was developed for the simultaneous determination of 17 synthetic and natural pyrethroids. A comparison of solid-phase extraction (SPE) versus DLLME for water samples and only "dilute and shoot" versus the additional extract cleanup by DLLME for sediment samples is reported. Chloroform was the extracting solvent in the DLLME technique for both water and sediment samples. Ultrasonic energy was applied to fully extract the analytes into fine droplets, providing high recoveries in short times. Method detection limits (MDLs) ranged from 0.12 to 0.62 ng L-1 and recoveries from 70 to 119% with RSD values 2-15% (n = 5) for water samples. In sediment samples, MDLs ranged from 0.50 to 2.50 ng g-1 and recoveries from 71 to 112% with RSDs 2-16% (n = 5). The proposed method showed a good linearity within the range of 10-500 ng mL-1, with coefficients of determination (R 2) higher than 0.99. Matrix effects were observed for most compounds in water and sediment (ME% < -10%). The proposed methodology was applied for the analysis of water and sediment samples from Albufera wetland and Turia River. Acrinathrin (48 ng g-1) and etofenprox (16 ng g-1) were detected in sediment samples. Graphical abstract Pyrethrins and pyrethroid determination in water and sediments by DLLME and LC-MS/MS.

Analysis of the presence of perfluoroalkyl substances in water, sediment and biota of the Jucar River (E Spain). Sources, partitioning and relationships with water physical characteristics.

The presence, sources and partitioning of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylate, C4, C6-C10 sulfonates and C8 sulfonamide) were assessed in water, sediment, and biota of the Jucar River basin (E Spain). Considering the three matrices, perfluoropentanoate (PFPeA) and perfluorooctane sulfonate (PFOS) were the most frequent compounds, being remarkable the high occurrence of short-chain PFASs (C≤8), which are intended to replace the long-chain ones in several industrial and commercial applications. In general, all samples were contaminated with at least one PFAS, with the exception of three fish samples. Mean concentrations detected in sediments (0.22-11.5ng g(-1)) and biota (0.63-274µgkg(-1)) samples were higher than those measured in water (0.04-83.1ngL(-1)), which might suggest (bio) accumulation. The occurrence of PFAS is related to urban and industrial discharges (Cuenca city in the upper part of basin, and car's factory, and effluents of the sewage treatment plant (STP) of Alzira, in the lower part). Increasing pollution gradients were found. On the other hand, higher contamination levels were observed after regulation dams of the catchment pointing out their importance in the re-distribution of these contaminants. None of the hazard quotients (HQ) calculated indicate potential risk for the different tropic levels considered (algae, Daphnia sp. and fish). PFAS concentrations found in this study can be considered in acceptable levels if compared to existing Regulatory Legislation and, consequently, they do not pose an immediate human health risk.

Transformation products of emerging contaminants in the environment and high-resolution mass spectrometry: a new horizon.

It is crucial to study the presence of transformation products (TPs) of emerging contaminants that can be potentially found in the environment after biological or chemical degradation. This review focuses on the potential and shortcomings of high-resolution mass spectrometry (HRMS) to identify these TPs, with emphasis on recent developments in mass analyzers, data evaluation, and compound identification workflows and applications. Advances in HRMS technologies, including direct introduction or in-line chromatographic separation modes, ionization techniques, mass analyzers, and detection methods, have led to powerful tools to assess the molecular changes and the opening of new horizons to identify unknown molecules. Advances in HRMS pertaining to the generation of analytical data for the main methods to identify TPs, including nontargeted and targeted approaches as they are applied to elucidate the structure of TPs, are also discussed.