Molecular formula assignment of dissolved organic matter by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry using two non-targeted data processing approaches: A case study from recirculating aquaculture systems.

BACKGROUND: The accumulation of dissolved organic matter (DOM) poses an issue in the management of the water quality from recirculating aquaculture systems (RAS), but its characterization is often not detailed enough to understand the DOM transformations in RAS. In this study, we investigated the application of two distinct non-targeted data processing approaches using ultra-performance liquid chromatography (UPLC) with quadrupole time-of-flight mass spectrometry (QTOF-MS) and two software with different algorithmic designs: PetroOrg and Progenesis QI to accurately characterize the molecular composition of DOM in RAS by UPLC-QTOF-MS. RESULTS: The UPLC-QTOF-MS resolution in combination with PetroOrg and Progenesis QI software successfully assigned 912 and 106 unique elemental compositions, respectively, including compounds containing carbon, hydrogen, and oxygen (CHO) and nitrogen-containing CHO compounds (CHON), in the DOM samples from RAS. The results of these two distinct data processing approaches were consistent with the list of DOM formulas from RAS identified by higher resolution mass spectrometry techniques confirming their reliability. PetroOrg approach revealed only compositional information in the DOM samples from RAS, while Progenesis QI in addition to identifying new elemental compositions, increased their chemical space by giving information about their polarity and their possible key structures. DOM samples from RAS were found to be rich in unsaturated CHO compounds, with tentatively key structures of terpenoids with medium polarity indicating natural origins in their composition. The analysis also revealed probable structures of sucrose fatty acid esters and polyethylene glycol, indicating anthropogenic sources. SIGNIFICANCE AND NOVELTY: The combination of these two non-targeted data processing approaches significantly improves the characterization of the complex mixture of DOM from RAS by UPLC-QTOF-MS reporting for the first time accurate DOM results in terms of its composition, while proposing its key structures. The presented methods can also be used to analyze different DOM samples with other HRMS techniques and software.

Occurrence and tissue distribution of 33 legacy and novel per- and polyfluoroalkyl substances (PFASs) in Baikal seals (Phoca sibirica).

Per- and polyfluoroalkyl substances (PFASs) are bioaccumulative and associated with adverse effects in both wildlife and humans. The occurrence of 33 PFASs was assessed in the plasma, liver, blubber, and brain of 18 Baikal seals (Phoca sibirica) (16 pups and 2 adult females) from Lake Baikal, Russia (in 2011). Of the 33 congeners analysed for: perfluorooctanosulfonic acid (PFOS), 7 long chain perfluoroalkyl carboxylic acids (C8-C14 PFCAs) and 1 branched PFCA (perfluoro-3,7-dimethyloctanoic acid; P37DMOA) were most frequently detected. The PFASs in plasma and liver with the highest median concentrations were legacy congeners: perfluoroundecanoic acid (PFUnA; plasma: 11.2 ng/g w.w.; liver: 7.36 ng/g w.w.), PFOS (plasma: 8.67 ng/g w.w.; liver: 9.86 ng/g w.w.), perfluorodecanoic acid (PFDA; plasma: 5.13 ng/g w.w.; liver: 6.69 ng/g w.w.), perfluorononanoic acid (PFNA; plasma: 4.65 ng/g w.w.; liver: 5.83 ng/g w.w.) and perfluorotridecanoic acid (PFTriDA; plasma: 4.29 ng/g w.w.; liver: 2.55 ng/g w.w.). PFASs were detected in the brain of Baikal seals, indicating that PFASs cross through the blood-brain barrier. In blubber, the majority of PFASs were detected in low abundance and concentrations. In contrast to legacy PFASs, novel congeners (e.g., Gen X) were either detected infrequently or not found in Baikal seals. The worldwide occurrence of PFASs in pinnipeds was compared and lower median concentrations of PFOS were observed in Baikal seals relative to other pinnipeds. Conversely, similar concentrations of long chain PFCAs were found in Baikal seals compared to other pinnipeds. Furthermore, human exposure was assessed by estimating weekly intakes (EWI) of PFASs through Baikal seal consumption. Although PFASs concentrations were comparatively low relative to other pinnipeds, consumption of Baikal seal could exceed current regulatory guidelines.

Analysis, occurrence and removal efficiencies of organophosphate flame retardants (OPFRs) in sludge undergoing anaerobic digestion followed by diverse thermal treatments.

Organophosphate flame retardants (OPFRs) are a complex group of contaminants to deal with in sewage sludge, as currently there is a lack of robust analytical methods to measure them and management strategies to remove them. To facilitate quantifications of the occurrence of OPFRs in sludge and to establish their removal efficiencies (REs%) during thermal treatments, a simple, reliable, and rapid sample preparation methodology was developed for the determination of 21 OPFRs in diverse sludge, ash and biochar matrices. Matrix-solid phase dispersion (MSPD) tailored to ultra-performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (MS/MS) was applied. Under optimal conditions, 0.5 g of freeze-dried sample were dispersed in 2 g of Bondesil C18, and 1.5 g of deactivated florisil were used as clean-up sorbent. The target analytes were extracted with 5 mL of acetone. The obtained extract was ready for analysis within 20 min without the need of any further treatment. The proposed methodology was assessed, providing absolute recoveries (Abs%) ranging from 50.4 to 112 % with good method repeatability (RSDs <17.9 %). Method limits of quantification ranged from 0.10 to 14.0 ng g-1 dry weight (d.w.). The optimized methodology was applied to raw-, digested-, combusted and pyrolyzed sludge samples collected from different waste treatment plants located in Norway, where 16 out of 21 OPFRs were detected in digested sludge samples up to 2186 ng g-1 (d.w.; sum concentration of OPFRs). Diverse thermal treatments of combustion and dry pyrolysis were assessed for the removal of OPFRs from sludge. Combustion at 300 °C reduced the concentrations of OPFRs by 98 % (in the ashes formed), whereas pyrolysis at temperatures >500 °C effectively removed the OPFRs in the produced biochar. Thermal treatments, in particularly dry pyrolysis, showed potential for achieving zero pollution management and recycling of OPFR contaminated sludge.

Determination of steroid hormones in grey seal (Halichoerus grypus) blood plasma using convergence chromatography tandem mass spectrometry.

A hybrid solid phase extraction (HybridSPE) protocol tailored to ultra-performance convergence chromatography tandem mass spectrometry (UPC2-MS/MS) was developed for the determination of 19 steroid hormones in grey seal (Halichoerus grypus) blood plasma. In this study, the protocol demonstrated acceptable absolute recoveries ranging from 33 to 90%. The chromatographic separation was carried out using a gradient elution program with a total run time of 5 min. For most target analytes, the method repeatability ranged from 1.9 to 24% and the method limits of quantification (mLOQs) ranged from 0.03 to 1.67 ng/mL. A total of 9 plasma samples were analysed to demonstrate the applicability of the developed method, and 13 steroid hormones were quantified in grey seal pup plasma. The most prevalent steroids: cortisol, cortisone, corticosterone, 11-deoxycortisol, progesterone and 17α-hydroxyprogesterone were detected at concentrations in the range of 12.6-40.1, 7.10-24.2, 0.74-10.7, 1.06-5.72, 0.38-4.38 and

Determination of the Oxidative Stress Biomarkers of 8-Hydroxydeoxyguanosine and Dityrosine in the Gills, Skin, Dorsal Fin, and Liver Tissue of Atlantic Salmon (Salmo salar) Parr.

Oxidative stress is a condition caused by an imbalance in the occurrence of reactive oxygen species in the cells and tissues of organisms. An ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed for the simultaneous determination of two oxidative stress biomarkers, 8-hydroxydeoxyguanosine (8OHDG) and dityrosine (DIY), in the gills, skin, dorsal fin, and liver tissue of Atlantic salmon (Salmo salar) parr. The use of target analyte-specific 13C and 15N internal standards allowed quantification of each target analyte to be performed through the standard solvent calibration curve. The relative recoveries [mean ± (relative standard deviation%)] of 8OHDG and DIY were 101 ± 11 and 104 ± 13% at a fortified concentration of 10 ng/mL (8OHDG) and 500 ng/mL (DIY), respectively, ensuring the accuracy of the extraction and quantification. The chromatographic separation was carried out using a gradient elution program with a total run time of 5 min. The limits of detection (LODs) were 0.11 and 1.37 ng/g wet weight (w.w.) for 8OHDG and DIY, respectively. To demonstrate the applicability of the developed method, it was applied in 907 tissue samples that were collected from Atlantic salmon parr individuals reared in an experimental land-based recirculating aquaculture system (RAS) treated with peracetic acid. Moreover, the possibility of using the dorsal fin as an alternative matrix for the minimally invasive assessment of oxidative stress in Atlantic salmon parr was introduced. To our knowledge, 8OHDG and DIY were used for the first time as biomarkers for biomonitoring the fish health (oxidative stress) of Atlantic salmon parr in RAS.

The Determination of Polycyclic Aromatic Hydrocarbons (PAHs) with HPLC-DAD-FLD and GC-MS Techniques in the Dissolved and Particulate Phase of Road-Tunnel Wash Water: A Case Study for Cross-Array Comparisons and Applications.

Accelerated solvent extraction (ASE) and solid phase extraction (SPE) protocols tailored to either gas chromatography mass spectrometry (GC-MS) or high-performance liquid chromatography coupled to diode-array and fluorescence detection (HPLC-DAD-FLD) were developed for the determination of EPA 16 polycyclic aromatic hydrocarbons (PAHs) in the particulate and dissolved phase of road-tunnel wash water. An analytical approach was developed, assessed, and applied on environmental samples collected from five road tunnels in Norway. The absolute recoveries ranged from 57 to 104% for the particulates, and from 42 to 79% for the dissolved water phase. The target PAH compounds were separated in 34.75 min using the GC method and in 22.50 min by HPLC. In the particulate phases, higher molecular weight PAHs were detected in the range of 0.043 to 0.93 µg/g, and lower molecular weight PAHs were detected in the range of 0.020 to 1.0 µg/g, while the intermediate ones were present in the range of 0.075 to 2.0 µg/g. In contrast to the particulates, the dissolved phase mainly contained lower molecular weight PAHs in the range of 0.0098 to 0.50 µg/L. GC-MS demonstrated lower detection limits (LODs) than HPLC-DAD-FLD for 13 out of the 16 PAHs. A cross-array comparison of the two analytical techniques indicated that some target PAHs were detected solely or in higher concentrations with HPLC-DAD-FLD, indicating the occurrence of false positive peaks or/and co-eluting components. The resulting concentrations in the road tunnel wash water samples were used to calculate specific PAH forensic ratios to pinpoint the potential sources of PAH pollution. These ratios revealed that there are several potential sources for the origin of PAHs in tunnel wash water.

Occurrence of bisphenols and benzophenone UV filters in wild brown mussels (Perna perna) from Algoa Bay in South Africa.

Bisphenols and benzophenone UV filters are contaminants present in a wide variety of plastic materials and consumer products. The scientific attention towards these contaminants has increased in recent years due to their presence in microplastics, their ubiquitous occurrence in the environment, and their known endocrine disrupting health effects. In this study, the occurrence of nine bisphenol and five benzophenone UV-filter analogues was assessed in wild brown mussels (Perna perna) collected from different sampling sites along the coast of Algoa Bay, South Africa. Eleven out of fourteen target analytes were detected, and bisphenol AP (BPAP) was detected for the first time in mussels, presenting the highest median concentration of 150 ng g-1 dry weight (d.w.) and a detection frequency of 91%. Regarding benzophenone UV-filters, median concentrations of the analogues (across all sites) ranged from 2.01 to 10.6 ng g-1 d.w., with benzophenone-1 (BzP-1) and benzophenone-3 (BzP-3) presenting the highest concentrations. Human exposure was assessed by estimating daily intakes (EDI) of the target analytes through mussel consumption. To our knowledge, this is the first study from the African continent on the occurrence of bisphenols and benzophenone UV-filters in a large population (n=138) of wild brown mussels.

Rapid Determination of Per- and Polyfluoroalkyl Substances (PFAS) in Harbour Porpoise Liver Tissue by HybridSPE®-UPLC®-MS/MS.

A rapid hybrid solid phase extraction (HybridSPE®) protocol tailored to ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC®-ESI-MS/MS) analysis was developed for the determination of 15 per- and polyfluoroalkyl substances (PFAS) in liver tissue from harbour porpoises (Phocoena phocoena). The HybridSPE® technique has been applied in trace concentration bioanalysis, but it was mainly used for liquid biological media until now. In this study, the protocol was applied on tissue matrix, and it demonstrated acceptable absolute recoveries (%) ranging from 44.4 to 89.4%. The chromatographic separation was carried out using a gradient elution program with a total run time of 4 min. The inter-day method precision ranged from 2.15 to 15.4%, and the method limits of detection (LODs) ranged from 0.003 to 0.30 ng/g wet weight (w.w.). A total of 20 liver samples were analyzed to demonstrate the applicability of the developed method in liver tissue from a wildlife species.

Occurrence of Bisphenols and Benzophenone UV Filters in White-Tailed Eagles (Haliaeetus albicilla) from Smøla, Norway.

There is a growing concern about the occurrence of bisphenols and benzophenone UV filters in natural ecosystems, while data are limited regarding their actual occurrence in wildlife species, especially in raptors. In this study, concentrations of bisphenol and benzophenone UV filter analogues were determined in liver tissue samples (n = 38) from white-tailed eagles (Haliaeetus albicilla) that were found dead in Smøla (2006-2018), which is a Norwegian municipality that holds one of the densest breeding populations of white-tailed eagles in Europe. Bisphenol AF (BPAF; a fluorinated analogue) was the most ubiquitous contaminant since it was detected in 32 liver samples at concentrations ranging from 1.08 to 6.68 ng/g wet weight (w.w.), followed by bisphenol A (BPA, mean 10.4 ng/g w.w.), benzophenone-1 (BzP-1, mean 3.24 ng/g w.w.), and 4-hydroxybenzophenone (4-OH-BzP, mean 0.62 ng/g w.w.). The concentrations found in livers suggested that white-tailed eagles potentially accumulate bisphenols and benzophenone UV filters, which raises concern, as these plastic and personal care product-related emerging contaminants can show endocrine-disrupting properties. The high detection frequency of the fluorinated BPAF warrants further attention as other fluorinated compounds have proven to be extremely persistent and potentially harmful to wildlife.

Microplastic fibres from synthetic textiles: Environmental degradation and additive chemical content.

Microplastic fibres (MPFs) often make up the largest fraction of microplastic pollution in aquatic environments, yet little is known about their degradative fate and persistence. This study investigates the environmentally relevant photodegradation of common MPFs: polyester (PET), polyamide (PA) and polyacrylonitrile (PAN), their respective additive chemical profile, together with their potential for additive leaching. MPFs were subject to ultraviolet (UV) exposure in seawater and freshwater media over 10 months. PET and PA MPFs showed significant fragmentation and surface changes following UV exposure, additionally PA showed evidence of chemical changes. PAN did not undergo significant photodegradation in the same exposure period. Chemicals tentatively identified in MPFs and aqueous leachates via non-target gas chromatography-mass spectrometry include monomers, UV stabilisers and degradation products. Characterisation of several bisphenols (BPs) and benzophenones (BzPs) was performed via ultraperformance liquid chromatography tandem mass spectrometry. Bisphenol A, bisphenol S and benzophenone-3 were quantified in all MPFs and wool at concentrations between 4.3 and 501 ng/g, with wool displaying the highest sum concentration of BPs and BzPs at 863 and 27 ng/g, respectively.

Characterizing changes of dissolved organic matter composition with the use of distinct feeds in recirculating aquaculture systems via high-resolution mass spectrometry.

Recirculating aquaculture systems (RAS) are a new alternative to traditional aquaculture approaches, allowing full control over the fish production conditions, while reducing the water demand. The reduction of water exchange leads to an accumulation of dissolved organic matter (DOM) that can have potential effects on water quality, fish welfare and system performance. Despite the growing awareness of DOM in aquaculture, scarce scientific information exists for understanding the composition and transformation of DOM in RAS. In this study, a non-targeted approach using ultra-performance liquid chromatography coupled to a hybrid quadrupole-time of flight mass spectrometer (UPLC-QTOF-MS) was used to characterize compositional changes of low molecular weight (LMW) DOM in RAS, when operated under two different feed types. A total of 1823 chemicals were identified and the majority of those contained a CHON chemical group in their structure. Changes in the composition of LMW-DOM in RAS waters were observed when the standard feed was switched to RAS feed. The DOM with the use of standard feed, consisted mainly of lignin/CRAM-like, CHO and CHOS chemical groups, while the DOM that used RAS feed, was mainly composed by unsaturated hydrocarbon, CHNO and CHNOS chemical groups. The Bray-Curtis dissimilarity cluster demonstrated differences in the composition of DOM from RAS and was associated to the type of feed used. When the RAS feed was used, the Kendrick mass defect plots of -CH2- homologous units in the pump-sump (after the water treatment) showed a high removal capacity for CHNO, CHNOS and halogenated chemicals with high Kendrick mass defect, KMD > 0.7. To our knowledge, this is the first report of LMW-DOM characterization of RAS by high-resolution mass spectrometry (HRMS).

Identification and Characterization of a Streptomyces albus Strain and Its Secondary Metabolite Organophosphate against Charcoal Rot of Sorghum.

Streptomycesalbus strain CAI-21 has been previously reported to have plant growth-promotion abilities in chickpea, pigeonpea, rice, and sorghum. The strain CAI-21 and its secondary metabolite were evaluated for their biocontrol potential against charcoal rot disease in sorghum caused by Macrophomina phaseolina. Results exhibited that CAI-21 significantly inhibited the growth of the pathogen, M. phaseolina, in dual-culture (15 mm; zone of inhibition), metabolite production (74% inhibition), and blotter paper (90% inhibition) assays. When CAI-21 was tested for its biocontrol potential under greenhouse and field conditions following inoculation of M. phaseolina by toothpick method, it significantly reduced the number of internodes infected (75% and 45% less, respectively) and length of infection (75% and 51% less, respectively) over the positive control (only M. phaseolina inoculated) plants. Under greenhouse conditions, scanning electron microscopic analysis showed that the phloem and xylem tissues of the CAI-21-treated shoot samples were intact compared to those of the diseased stem samples. The culture filtrate of the CAI-21 was purified by various chromatographic techniques, and the active compound was identified as "organophosphate" by NMR and MS. The efficacy of organophosphate was found to inhibit the growth of M. phaseolina in the poisoned food technique. This study indicates that S.albus CAI-21 and its active metabolite organophosphate have the potential to control charcoal rot in sorghum.

Bioaccumulation potential of bisphenols and benzophenone UV filters: A multiresidue approach in raptor tissues.

Environmental exposure to bisphenols and benzophenone UV filters has received considerable attention due to the ubiquitous occurrence of these contaminants in the environment and their potential adverse health effects. The occurrence of bisphenols and benzophenone UV filters is well established in human populations, but data is scarce for wildlife, and especially for raptors (birds of prey, falcons and owls). In this study, concentrations of eight bisphenols and five benzophenone UV filters were determined in six raptor tissues, including muscle, kidney, liver, brain, preen gland (uropygial gland) and adipose. The tissue samples (n = 44) were taken from dead raptor species (1997-2011), including Eurasian sparrowhawks (Accipiter nisus, n = 2) and long-eared owls (Asio otus, n = 2), both from France, and white-tailed eagles (Haliaeetus albicilla, n = 16) from Greenland. Overall, six bisphenols and four benzophenone UV filters were found in the samples. Bisphenol A (BPA), bisphenol F (BPF), benzophenone-8 (BzP-8) and 4-hydroxybenzophenone (4-OH-BzP) were the most abundant contaminants, accounting for median concentrations of 67.5, 3.01, 27.1 and 9.70 ng/g wet weight (w.w.), respectively. The potential role of the preen gland as a major excretory organ for bisphenols and benzophenone UV filters was suggested since the median sum concentration of the two contaminant classes in the white-tailed eagle tissues showed higher bioaccumulation potential in the preen gland (5.86 ng/g w.w.) than the liver (2.92) and kidney (0.71). The concentrations of these contaminants in the tissues of the three raptor species indicated a pattern of increasing detection rates and median concentrations with an increase of the species size and their expected trophic position. To the best of our knowledge, this is the first peer-reviewed study to document multiresidues of both contaminant classes in raptor tissues.

Benzotriazoles, benzothiazoles and trace elements in an urban road setting in Trondheim, Norway: Re-visiting the chemical markers of traffic pollution.

Road traffic emissions are known to contribute heavily to the pollution in urban environments. The aim of this study was to establish specific traffic pollution markers in an urban road setting based on the occurrence profiles of benzotriazoles, benzothiazoles and trace elements in road dust and relevant matrices, including airborne particulate matter and core asphalt. Benzotriazoles and benzothiazoles are high-production volume chemicals that are used as complexing and anticorrosive agents for metals, act as vulcanizing accelerators for rubber materials, and possess anti-freezing/anti-icing properties. In this study, six benzothiazoles (benzothiazole, 2­morpholin­4­yl­benzothiazole, 2­hydroxy­benzothiazole, 2­thio­benzothiazole, 2­methylthio­benzothiazole, and 2­amino­benzothiazole), seven benzotriazoles (1H­benzotriazole, 1­hydroxy­benzotriazole, 5­chloro­1H­benzotriazole, tolyltriazole, xylyltriazole, benzotriazole­5­carboxyl acid, and 5­amino­1H­benzotriazole), and 66 trace elements were determined in road dust samples from a sub-arctic urban road setting in Norway, and seasonal occurrence profiles were assessed between the studded and the non-studded tire season. The road dust was collected as suspended particulate matter in an aqueous phase with the introduced dust sampler in Scandinavia, the Wet Dust Sampler. The concentrations of the sum of seven benzotriazoles (Σ(7)BTRs) and six benzothiazoles (Σ(6)BTHs) in road dust ranged from 191 to 3054 ng/L and 93.4 to 1903 ng/L, respectively. To the best of our knowledge, 1H­benzotriazole and tolyltriazole are reported for the first time as suitable markers of metal corrosion in vehicles. From the benzothiazole class, 2­thio­benzothiazole was found to be a suitable marker of tire rubber particles, while its methylated derivative, 2­methylthio­benzothiazole, was found to be a marker of chemical leaching. In addition, different types of new unused tires (summer, studded, and non-studded) were analyzed to assess their benzothiazoles and benzotriazoles content. Based on the concentrations found for benzotriazoles and benzothiazoles in airborne particulate matter, human exposure doses were calculated, and the estimated daily intake doses were found on the order of picograms per day.