Is Fucus a suitable biomonitoring organism for polycyclic aromatic hydrocarbon contamination? A study from the Faroe Islands.

To evaluate seaweed as a biomonitoring organism, Fucus was sampled in the Faroe Islands. Nineteen PAHs, including the EPA 16, and four groups of alkylated PAHs were quantified using GC-MS analysis of extracts obtained using a modified QuEchERS method with ultrasonication in acetonitrile, back-extraction into hexane, and Florisil® cleanup. Samples from the harbor of Tórshavn collected at high tide were the most polluted with PAH concentrations between 1.3 × 102 and 1.7 × 102 ng/g wet weight. All samples contained a factor 10 higher concentrations of alkylated PAHs compared to their parent compounds. These results suggest that Fucus might be suitable as a biomonitoring organism for PAH pollution. Differences between samples collected in close proximity and on different days were observed (same range of RSD 14-120% and 60-102%, respectively), suggesting that water exchange, tide levels, and direct exposure to surface diesel pollution have a strong influence on pollutant uptake in Fucus. The findings stress the need for further evaluation of the sampling strategy.

System stability and signal enhancement with analyte protectants: Gas chromatography analysis of oxygenated-polycyclic aromatic hydrocarbons.

Matrix effects can affect detection limits, precision, and accuracy and lead to signal enhancement or suppression effects in gas chromatography analysis. Analyte protectants, such as shikimic acid and gluconolactone, can imitate the effect of matrix components and reduce the differences in matrix effect between samples. This study aimed to investigate the ability of analyte protectants to enhance gas chromatography detector signals of different oxygenated-polycyclic aromatic hydrocarbons. Addition of 100 µg L-1 shikimic acid and 200 µg L-1 gluconolactone effectively enhanced detector response of the investigated target compounds. Addition of a higher content of analyte protectants did not result in any further enhancement. It was found that between four and eleven consecutive injections of a standard solution with analyte protectants were required to obtain a stable compound response. The long-term signal stability was then maintained with subsequent injections, though an overall negative drift of the system was observed over the sequence of 200 investigated injections. Analysis of the actual sample matrix instead of standards in pure solvent, as presented in this study, could also be a way to minimize the required number of injections. Shikimic acid and gluconolactone were first and foremost able to enhance signals of oxygenated-polycyclic aromatic hydrocarbons with similar functional groups (hydroxyl) in their molecular structure. It can be relevant to consider alternative analyte protectants with different functional groups according to the type of target compounds investigated.

Quantitative Nontarget Analysis of CECs in Environmental Samples Can Be Improved by Considering All Mass Adducts.

Quantitative nontarget analysis (qNTA) for liquid chromatography coupled to high-resolution mass spectrometry enables a more comprehensive assessment of environmental samples. Previous studies have shown that correlations between a compound's ionization efficiency and a range of molecular descriptors can predict the compound's concentration within a factor of 5. In this study, the qNTA approach was further improved by considering all mass adducts instead of only the protonated ion. The model was based on a quantitative structure-property relationship (QSPR), including 216 contaminants of emerging concern (CECs), of which 80 exhibited adduct formation that accounted for >10% of the total peak intensity. When all mass adducts were included, the test set coefficient of determination improved to Q2 = 0.855 compared to Q2 = 0.670 when only the protonated ions were considered (test set median RF error factor 1.6). The inclusion of all adducts was also important to transfer the RF QSPR model reliably. It was assumed that RF variations are sequence-dependent; therefore, a second QSPR model for the prediction of the transferability factor was built for each sequence. For validation, samples were analyzed up to two years apart. The median prediction fold change was 1.74 for analytical standards (63 compounds) and 2.4 for enriched wastewater effluent samples (41 compounds), with 80% of the compounds predicted within a fold change of 2.4 and 3.3, respectively. The model was also validated on a second instrument, where 80% of the 26 compounds in wastewater effluent were predicted within a factor of 3.8.

Catchment area, fate, and environmental risks investigation of micropollutants in Danish wastewater.

This study aimed to investigate the spatial distribution of micropollutants in wastewater related to catchment area, and their environmental risks and fate. About 24-h flow proportional effluent (n = 26) wastewater samples were collected from eight WWTPs across Denmark. From five of these WWTPs corresponding influent samples (n = 20) were collected. Samples were enriched by multi-layer solid phase and analysed by liquid chromatography-high-resolution mass spectrometry and comprehensive two-dimensional gas chromatography with high-resolution mass spectrometry detection. We detected and quantified 79 micropollutants from a list of 291 micropollutants in at least one influent or effluent wastewater sample. From this we found that 54 micropollutants decreased in concentrations during wastewater treatment, while O-desmethylvenlafaxine, carbamazepine, amitriptyline, benzothiazole, terbutryn, and citalopram increased in concentrations through the WWTP.The toxicity of effluent wastewater samples was assessed by EC50 using Raphidocelis subcapitata (R. subcapitata) and LC50 using the crustacean Daphnia magna (D. Magna), for which six micropollutants were detected above the predicted no-effect concentration. Our study demonstrates that catchment area influences the micropollutant composition of wastewater. Out of 19 pharmaceuticals, the measured concentration in influent wastewater was predicted within a factor of 10 from sale numbers and human excretion, which demonstrates the strong influence of catchment area on micropollutant composition.

Supercritical Fluid Chromatography Coupled to High-Resolution Mass Spectrometry Reveals Persistent Mobile Organic Compounds with Unknown Toxicity in Wastewater Effluents.

Broad screening approaches for monitoring wastewater are normally based on reversed-phase liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS). This method is not sufficient for the very polar micropollutants, neglected in the past due to a lack of suitable analytical methods. In this study, we used supercritical fluid chromatography (SFC) to detect very polar and yet-undetected micropollutants in wastewater effluents. We tentatively identified 85 compounds, whereas 18 have only rarely been detected and 11 have not previously been detected in wastewater effluents such as 17α-hydroxypregnenolone, a likely transformation product (TP) of steroids, and 1H-indole-3-carboxamide, a likely TP from new synthetic cannabinoids. Suspect screening of 25 effluent wastewater samples from 8 wastewater treatment plants revealed several distinct potential pollution sources such as a pharmaceutical company and a golf court. The analysis of the same samples with LC-HRMS showed clearly how SFC increases the ionization efficiency for low-molecular-weight micropollutants (m/z < 300 Da) by a factor 2 to 87 times, which significantly improved the mass spectra for identifying very polar compounds. In order to assess which micropollutants might be of environmental concern, literature and toxicological databases were screened. There was a lack of available hazard and bio-activity data for regulatory-relevant in vitro and in vivo assays for >50% of the micropollutants. Especially, 70% of the data were lacking for the whole organism (in vivo) tests.

Investigation of the spatial distribution of airborne polycyclic aromatic hydrocarbons using Rhytidiadelphus squarrosus in Tórshavn, Faroe Islands.

Due to adverse effects of Polycyclic Aromatic Hydrocarbons (PAHs) on human health, it is important to understand how airborne PAHs, are spatially distributed within urban areas. Moss has been shown to be a suitable material for biomonitoring of airborne PAH pollution. In this study, the moss Rhytidiadelphus squarrosus was sampled throughout Tórshavn, Faroe Islands. 53 Rhytidiadelphus squarrosus samples were extracted using a matrix solid-phase dispersive extraction method and analysed for 19 parent PAHs and six groups of alkylated PAHs using gas chromatography mass-spectrometry. All PAHs were quantified in at least one Rhytidiadelphus squarrosus sample, and the sum of the EPA 16 PAHs (Æ©PAHEPA16) ranged from 0.90 to 344 µg kg-1 dry weight. Higher concentrations were found close to the harbour and the main roads. The spatial correlation was investigated for the Æ©PAHEPA16, pyrene, fluoranthene, chrysene, benzo(e)pyrene, benzo(g,h,i)perylene, C1-phenanthrenes/C1-anthracenes, and C2-phenanthrenes/C2-anthracenes using variograms. The effective range of the spatial correlation was between 500 to 700 m of all PAHs. The evaluation of diagnostic ratios of fluoranthene to pyrene, and benzo(a)anthracene to chrysene suggest that different pollution sources affect urban areas of different types. To the best of our knowledge, this is the first time airborne PAH pollution patterns were mapped in an Arctic town, and the first time, Rhytidiadelphus squarrosus was used for tracing PAH pollution sources. Rhytidiadelphus squarrosus is suitable for biomonitoring and mapping PAH pollution within urban areas since it is widespread, and suitable for mapping PAHs.

Removal of a complex VOC mixture by potted plants-effects on soil microorganisms.

Microorganisms in the soil of potted plants are important for removal of volatile organic compounds (VOCs) from indoor air, but little is known about the subject. The aim of this study was therefore to obtain a better understanding of the effect of VOCs on the microbial community in potted plants. Hedera helix was exposed to gasoline vapors under dynamic chamber conditions for 21 days and three main parameters were investigated. These were (1) removal of the target compounds heptane, 3-methylhexane, benzene, toluene, ethylbenzene, m,p-xylene, and naphthalene from the gasoline mixture; (2) toluene mineralization; and (3) bacterial abundance and bacterial community structure. H. helix was able to reduce the concentration of the target compounds in the continuously emitted gasoline by 25-32%, except for naphthalene, which was too low in concentration. The soil microcosm of gasoline exposed plants had for an initial 66 h increased toluene mineralization rate compared to the soil microcosm in the soil of plants exposed to clean air. Bacterial abundance was decreased in response to gasoline exposure while bacterial community structure was changed. The change in bacterial community structure was, however, different between the two experiments indicating that several taxonomic units can degrade gasoline components. Especially the genera Rhodanobacter and Pseudonorcardia significantly increased in abundance in response to gasoline vapors. Bauldia, Devosia, and Bradyrhizobium, on the other hand, decreased.

Investigation of micropollutants in household waste fractions processed by anaerobic digestion: target analysis, suspect- and non-target screening.

Household waste represents a major source of energy, nutrients, and recyclable material. In order to exploit benefits and avoid hazards in the context of circular economy, the risk profile towards human and the environment should be assessed. Here, we investigated the presence of micropollutants by quantitative target analysis, suspect and non-target screening and evaluated changes in the chemical fingerprint upon anaerobic digestion. Extracts were analyzed by reversed phase liquid chromatography high-resolution mass spectrometry (LC-HRMS) and gas chromatography mass spectrometry (GC-MS). Thirty-one of 51 target micropollutants were detected in low ng/mL levels except for few detections at µg/mL levels. The micropollutants quantified in this study included the following: pharmaceuticals (salicylic acid, amitriptyline, carbamazepine); biocides (triclocarban, 2-phenylphenol); industrial compounds used in, e.g., paper industry (pentachlorphenol, PFOS, PFOA, bisphenol A); aromatics, polycyclic aromatics, and heteroaromatics, and their alkylated, hydroxylated, or carboxylated analogues. Fifty of 206 compounds from the suspect screening list were tentatively identified. These included phthalates, methylparaben, phenol, benzophenone, and pharmaceuticals, e.g., ibuprofen. Most compounds detected by GC-MS decreased more than twofold in peak height or remained unaffected by the anaerobic digestion, and very few increased more than twofold, e.g., p-cresol, menthol, and octadecanal. From the LC-HRMS non-target screening analysis, 250 chemical components were resolved using the multiway curve resolution technique PARAFAC2; of these, carbidopa was the only identified unknown.

Source-Supported Suspect Screening (4S) of Phytotoxins in Terrestrial and Aquatic Environments: A Field Study of Lupinus angustifolius L. (Blue Lupin).

Phytotoxins (PTs) are bioactive secondary metabolites produced by plants. More recently, they have been recognized as important aquatic micropollutants. Despite that, only a few PTs have been detected and reported in terrestrial and aquatic environments, while their source and leaching pathways remain largely unclear. Herein, we established a novel approach named source-supported suspect screening (4S) to discover PTs in different environments, investigate their environmental occurrences, identify their sources, and initiate discussions on their leaching mechanisms. The 4S-approach was demonstrated on a five-month Lupinus angustifolius L. (L. angustifolius) crop field experiment, where plant, topsoil, drainage water, and surface water were sampled and analyzed. As a result, 72 PTs (flavonoids and alkaloids) were identified at high confidence, with 10 PTs fully confirmed. Fifty-three PTs detected in soil or water were linked to L. angustifolius, among which 26 PTs were coherently detected in all three environmental compartments. The occurrence and abundance of PTs in terrestrial soil and aquatic environments were influenced by the plant growth stage and precipitation. Soil served as an intermedium when PTs leached from L. angustifolius to the drainage water, while the degree of retardation and eventual occurrence in the aquatic environment depended on both PTs and soil physico-chemical properties.

Long-term patterns of hydrocarbon biodegradation and bacterial community composition in epipelagic and mesopelagic zones of an Arctic fjord.

Oil spill attenuation in Arctic marine environments depends on oil-degrading bacteria. However, the seasonally harsh conditions in the Arctic such as nutrient limitations and sub-zero temperatures limit the activity even for bacteria capable of hydrocarbon metabolism at low temperatures. Here, we investigated whether the variance between epipelagic (seasonal temperature and inorganic nutrient variations) and mesopelagic zone (stable environmental conditions) could limit the growth of oil-degrading bacteria and lead to lower oil biodegradation rates in the epipelagic than in the mesopelagic zone. Therefore, we deployed absorbents coated with three oil types in a SW-Greenland fjord system at 10-20 m (epipelagic) and 615-650 m (mesopelagic) water depth for one year. During this period we monitored the development and succession of the bacterial biofilms colonizing the oil films by 16S rRNA gene amplicon quantification and sequencing, and the progression of oil biodegradation by gas chromatography - mass spectrometry oil fingerprinting analysis. The removal of hydrocarbons was significantly different, with several polycyclic aromatic hydrocarbons showing longer half-life times in the epipelagic than in the mesopelagic zone. Bacterial community composition and density (16S rRNA genes/ cm2) significantly differed between the two zones, with total bacteria reaching to log-fold higher densities (16S rRNA genes/cm2) in the mesopelagic than epipelagic oil-coated absorbents. Consequently, the environmental conditions in the epipelagic zone limited oil biodegradation performance by limiting bacterial growth.

A non-target screening study of high-density polyethylene pipes revealed rubber compounds as main contaminant in a drinking water distribution system.

Polyethylene (PE) pipes are often the material of choice for water supply systems, thanks to their favorable properties, such as high strength-density ratio and corrosion resistance. However, previous studies have shown that organic compounds can migrate from PE pipes to the water. This study aimed to identify potential organic compounds migrating from high-density PE (HDPE) pipes used to distribute drinking water in Denmark, based on laboratory experiments and sampling in the distribution system using a two-tiered study design. In the first tier, migration of volatile and semi-volatile organic compounds (VOCs and semi-VOCs) from HDPE pipes were investigated over one, three, and nine days in laboratory experiments, performed according to modified standards for migration testing (EN 12,873-1). The analytical workflow consisted of solid-phase extraction (SPE) for 10,000 times enrichment and gas chromatography - mass spectrometry (GC-MS) analysis from the water phase after migration. A total of 133 compounds originating from the PE pipes were detected. Thirty-one compounds were detected by suspect screening (SS), while the remaining 102 compounds were detected by non-target screening (NTS) analysis. Among the detected compounds were also hindered amine stabilizers (HALS), flame retardant, and plasticizer tris(2-chloroethyl) phosphate. In the second tier, drinking water from a water distribution system in Copenhagen, Denmark, with a newly installed HDPE pipe was sampled and analyzed with GC-MS and liquid chromatography high-resolution mass spectrometry (LCHRMS). A total of 51 compounds were detected in the water, 12 of which were assigned to migration from HDPE. Surprisingly, HDPE antioxidants and their degradation products contributed only a relatively small percentage of the total measured compound intensities in the drinking water distribution system. Instead, a larger proportion of the compounds detected were assigned to rubber seals, used upstream in the water system from the abstraction site to delivery at the consumer tap. Seals are considered trifle in the larger picture of materials in contact with drinking water, however these results may cause a reconsideration of this position.

Ultra-high-performance supercritical fluid chromatography-mass spectrometry for the analysis of organic contaminants in sediments.

A nontarget screening method was developed based on D-optimal designs for ultra-high performance supercritical fluid chromatography with positive and negative electrospray ionization mode mass spectrometry. A mixture of organic contaminants such as pesticides, steroids, surfactants, phenolic and fatty acids, and polycyclic aromatic hydrocarbon derivatives, was used for the optimization. An aprotic mixture of dichloromethane and acetone [3:1] performed overall best as the injection solvent. The highest peak capacities (n) were accomplished at the shallowest gradient (1%B/min), ammonium formate (n = 378 in negative ionization mode), or ammonium acetate (n = 327 in positive ionization mode) in methanol as the modifier. Capillary voltage, make-up solvent flow rate, water, and additive concentration were the most significant factors for improving peak intensity: higher peak intensities were obtained at lower additive concentrations (5mM ammonium formate), and with 5% water in positive ionization mode. Conversely, water had detrimental effects in negative ionization mode. The optimized method was used to quantify organic contaminants in 17 freshwater sediment samples from Copenhagen, Denmark. Out of 50 monitored contaminants, 35 were detected in at least one sample. Further, the method has a potential for target and nontarget screening analysis of organic contaminants in solid matrices.

Anterolateral versus modified posterolateral approach for tibial plateau fractures with involvement of the posterior column: a cadaveric study.

INTRODUCTION: The aim of this study was to compare the reduction quality of the anterolateral (AL) and modified posterolateral approach (PL) in lateral tibial plateau fractures involving the posterior column and central segments. METHODS: Matched pairs of pre-fractured cadaveric tibial plateau fractures were treated by either AL approach (supine position) or PL approach (prone position). Reduction was controlled by fluoroscopy and evaluated as satisfying or unacceptable. Afterwards, the reduction was examined by 3D scan. RESULTS: 10 specimens (3 pairs 41B3.1, 2 pairs 41C3.3) were evaluated. PL approach achieved significantly (p 0.00472) better fracture reduction results (0.4 ± 0.7 mm) of the posterior column compared to the AL group (2.1 ± 1.4 mm). Fracture steps involving the central area of the lateral plateau were insufficiently reduced after fluoroscopy using both approaches. CONCLUSION: Optimal reduction of displaced tibial plateau fractures involving the posterolateral column necessitates a posterior approach, which can be conducted in prone or lateral positioning. The anterolateral approach is indicated in fractures with minor displacement of the posterolateral rim but fracture extension in the latero-central segments. In these cases, an additional video-assisted reduction or extended approaches are helpful.

Second dimension retention indices in "normal" orthogonality comprehensive two-dimensional gas chromatography using single standard injection generated isovolatility curves.

This work builds upon recent developments in the field of second dimensional (2D) retention indices (RI) for use in comprehensive two-dimensional gas chromatography (GC×GC), expanding application to the most commonly used "normal" orthogonality column configuration, where 2D RI are rarely employed. Initially, one dimensional retention indices for 80 wastewater pollutants were determined by GC-MS on a mid-polar ZB-50 column. In order to determine the 2D RIs for peaks detected in wastewater extracts separated by GC×GC -MS, a single injection of a ten-compound standard mix allowed the construction of model-generated isovolatility curves. These curves were used for the determination of 2D RIs of compounds initially identified on the basis of the mass spectral match factor and 1D RIs. Good agreements (average deviation of 1.7%) were observed between the calculated 2D RIs and the measured reference RIs for these compounds. These results show that this approach provides an additional level of confidence for the identification of compounds detected in GC×GC-MS and demonstrates the potential of this approach for improved compound identification in non-targeted analysis.

Obtaining clean and informative mass spectra from complex chromatographic and high-resolution all-ions-fragmentation data by nonnegative parallel factor analysis 2.

A major challenge in processing of complex data obtained from chromatography hyphenated to mass spectrometry is to resolve chromatographically co-eluting compounds. In this study, we present a workflow for the resolution of ultra-high pressure liquid chromatography high-resolution mass spectrometry data obtained by the broadband data-independent acquisition MSE operation (UHPLCHRMSE). The workflow is based on a recently introduced algorithm for Parallel Factor Analysis 2 (PARAFAC2) that allows to enforce non-negativity on all the model coefficients. The workflow was tested on three sets of UHPLC-HRMSE measurements from a Lupinus angustifolius L. crop field study, which included plant tissue samples, soil samples and samples from drainage water as well as stream water close to the field. The three datasets included 93, 59, and 75 chromatographic runs in total for the plant, soil and water batches, respectively. Nonnegative-PARAFAC2 models were fitted on the summed high and low energy (HE and LE) traces on chromatographic intervals corresponding to spiked standard for the three sample sets independently. In soil and plant samples, 13 out of 14 spiked standards were resolved by NN-PARAFAC2 even in presence of chromatographic co-elution, and their mass spectral loadings could be matched to a reference spectrum. In contrast, only seven spiked standards were correctly resolved and matched for the water samples because a higher chromatographic baseline rendered the data noisier. The results show that the workflow we present can provide improved mass spectral selectivity for data-independent acquisition compared to using the raw mass spectra and can be used to match fragment ions from the HE trace, and precursor and adduct ions from the LE trace even in presence of co-eluting compounds.

Can analyte protectants compensate wastewater matrix induced enhancement effects in gas chromatography - mass spectrometry analysis?

This study aimed to investigate the ability of analyte protectants to enhance GC-MS signals and compensate matrix effects for a range of micropollutants in pure standard, effluent, and influent wastewater samples during analysis and detection. Wastewater samples were prepared for analysis using multilayer solid phase extraction for the purpose of extracting sample components with a broad range of physical-chemical properties. The sample extracts were either spiked or not spiked with target compounds and four analyte protectants: 3-ethoxy-1,2-propanediol, D-sorbitol, gluconolactone, and shikimic acid. In this way, it was possible to evaluate the matrix effects of wastewater samples and compare the use of analyte protectants with the conventional correction method of allocating a best matching internal standard to each target compound. A relation was observed between level of wastewater treatment and matrix effects, with the largest effects observed for influent samples and the smallest effects for effluent samples. Compensation of matrix effects with analyte protectants gave comparable results with the conventional correction method of allocating a best matching internal standard to each of the 13 investigated micropollutants. The best overall compensation was observed using analyte protectants and the internal standard correction method in combination.

Non-target screening of micropollutants and transformation products for assessing AOP-BAC treatment in groundwater.

Standard monitoring programs give limited insight into groundwater status, especially transformation products (TPs) formed by natural processes or advanced oxidation processes (AOP), are normally underrepresented. In this study, using suspect and non-target screening, we performed a comprehensive analysis of groundwater before and after AOP by UV/H2O2 and consecutively installed biological activated carbon filters (BAC). By non-target screening, up to 413 compounds were detected in the groundwater, with an average 70% removal by AOP. However, a similar number of compounds were formed during the process, shown in groundwater from three waterworks. The most polar compounds were typically the most stable during the AOP. A subsequent BAC filter showed removal of 95% of the TPs, but only 46% removal of the AOP remaining precursors. The BAC removal for polar compounds was highly dependent on the acidic and basic functional groups of the molecules. 49 compounds of a wide polarity range could be identified by supercritical fluid chromatography (SFC) and liquid chromatography (LC) with high resolution mass spectrometry (HRMS); of these, 29 compounds were already present in the groundwater. To the best of our knowledge, five compounds have never been reported before in groundwater (4-chlorobenzenesulfonic acid, dibutylamine, N-phenlybenzenesulfonamide, 2-(methylthio)benzothiazole and benzothiazole-2-sulfonate). A further five rarely reported compounds are reported for the first time in Danish groundwater (2,4,6-trichlorophenol, 2,5-dichlorobenzenesulfonic acid, trifluormethansulfonic acid, pyrimidinol and benzymethylamine). Twenty of the identified compounds were formed by AOP, of which 10 have never been reported before in groundwater. All detected compounds could be related to agricultural and industrial products as well as artificial sweeteners. Whereas dechlorination was a common AOP degradation pathway for chlorophenols, the (ultra-) short chain PFAs showed no removal in our study. We prioritized 11 compounds as of concern, however, the toxicity for many compounds remains unknown, especially for the TPs.

From data to reliable conclusions: Identification and comparison of persistent micropollutants and transformation products in 37 wastewater samples by non-target screening prioritization.

In this study, micropollutants in wastewater effluents were prioritized by monitoring the composition of influent and effluent wastewater by liquid chromatography - high-resolution mass spectrometry (LCHRMS) non-target screening (NTS) analysis. The study shows how important data pre-processing and filtering of raw data is to produce reliable NTS data for comparison of compounds between many samples (37 wastewater samples) analyzed at different times. Triplicate injections were critical for reducing the number of false-positive detections. Intensity drift corrections within and between batches analyzed months apart made peak intensities comparable across samples. Adjustment of the feature detection threshold was shown to be important, due to large intensity variations for low abundance compounds across batches. When the threshold correction cut-offs, or the filtering of relevant compounds by the occurrence frequency, were too stringent, a high number of false positive transformation products (TPs) were reported. We also showed that matrix effect correction by internal standards can over- or under-correct the intensity for unknown compounds, thus the TIC matrix effect correction was shown as an additional tool for a retention time dependent matrix effect correction. After these preprocessing and filtering steps, we identified 78 prioritized compounds, of which 36 were persistent compounds, defined as compounds with a reduction in peak intensity between influent and effluent wastewater <50%, and 13 compounds were defined as TPs because they occurred solely in the effluent samples. Some examples of persistent compounds are 1,3-diphenylguanidine, amisulpride and the human metabolites from losartan, verapamil and methadone. To our knowledge, nine of the identified TPs have not been previously described in effluent wastewater. The TPs were derived from metoprolol, fexofenadine, DEET and losartan. The screening of all identified compounds in effluent samples from eight wastewater treatment plants (WWTPs) showed that potential drugs of abuse, anti-psychotic and anti-depressant drugs were predominant in the capital city region, whereas the anti-epileptic agents and agricultural pesticides were dominant in more rural areas.

Non-target screening for the identification of migrating compounds from reusable plastic bottles into drinking water.

Reusable plastic sports bottles are used extensively worldwide, and little is known about the migration of chemicals from the bottles into drinking water. In this study, we investigated the chemical migration into drinking water stored for 24 h in new bottles, used bottles and bottles washed in the dishwasher. Non-target screening (NTS) by liquid-chromatography - high-resolution mass spectrometry (LC-HRMS) was performed to identify these compounds. We detected > 3500 dishwasher related compounds, with 430 showing migration even after subsequent flushing of the bottles. In addition, more than 400 plastic related compounds were detected, with high peaks for oligomers suspected to originate from the biodegradable polyester polycaprolactone, and aromatic amines, which may have been introduced as slip agents or antioxidants. These compounds have never been reported before in bottled water. Most of the identified compounds migrating out of the used bottles were plasticizers, antioxidants or photoinitiators. The presence of photoinitiators are of particular concern, due to possible endocrine disrupting effects. Furthermore, diethyltoluamide (DEET) was detected, which may have been formed from the plasticizer laurolactam. Typically, the dishwashing process enhanced the leaching of plastic related compounds, and even after additional water flushing, the average peak intensity of these compounds was only reduced by half.