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Monthly water samples were collected from the lower Mississippi and Pearl Rivers between January 2009 and August 2011 to investigate the heterogeneity in the dynamic variations of dissolved organic carbon (DOC), colloidal organic carbon, chromophoric and fluorescence dissolved organic matter (CDOM and FDOM), PARAFAC-derived fluorescent components, and other optical properties including spectral slope, specific UV absorbance (SUVA), and fluorescence indices between the two contrasting river systems. The lower Mississippi River exhibits relatively lower concentrations of DOC (306 ± 41 μM C) and CDOM (27.9 ± 5.7 m−1 at 254 nm), featuring lower aromaticity (indicated by SUVA 254) and apparent molecular weight (or higher spectral slope) with weak seasonal variability. The Pearl River, in contrast, has elevated levels of DOC (537 ± 212 μM C) and CDOM (66.4 ± 31.4 m−1), characterized by higher aromaticity, higher molecular weight, and significant seasonality, primarily originating from soil-derived allochthonous sources. The abundance of the >1 kDa colloidal DOC was, on average, 58 ± 3 % of the bulk DOC in the lower Mississippi River and 68 ± 6 % in the lower Pearl River. The >1 kDa high-molecular weight DOM (HMW-DOM) consistently had lower spectral slope and biological index (BIX) values, but higher humification index (HIX) values compared to both bulk DOM and low-molecular-weight DOM (LMW-DOM) counterparts. These trends could be representative of other similar large and small rivers. Four PARAFAC-derived fluorescent components (three humic-like and one protein-like) were identified for both rivers. A positive correlation between discharge and terrestrial humic-like fluorescent components indicated their dominant allochthonous sources, while the protein-like component decreased with increasing discharge, consistent with its autochthonic source and a dilution effect during high flow seasons. The occurrence of large flood events during the sampling period contributed to large DOC pulses, with DOM of higher aromaticity and HMW-DOM. This has important implications for coastal ocean ecosystems, which are increasingly impacted by river flooding events under changing climate conditions. Our results also provide an improved understanding of DOM dynamics in two representative rivers and establish a baseline dataset for future studies to assess changes in sources and composition of DOM and their impacts on the coastal ocean in response to climate, hydrological, and anthropogenic influences. • LMR exhibits lower DOC, CDOM and SUVA254, but higher spectral slope and weak seasonality • LPR has elevated DOC and CDOM, characterized by higher aromaticity and MW and significant seasonality • Colloidal DOC was lower (58 ± 3 %) in LMR but higher (68 ± 6 %) in LPR, with lower S and BIX but higher HIX in both rivers • Four PARAFAC-derived fluorescent components (three humic-like and one protein-like) were identified • Flood events were associated with large changes in DOM quantity and quality [ABSTRACT FROM AUTHOR]

Abstract This study investigated, using rapid small-scale column testing, the breakthrough of dissolved organic matter (DOM) and eleven emerging organic contaminants (EOCs) during granular activated carbon (GAC) filtration of different water qualities, including wastewater, surface water and synthetic water (riverine organic matter dissolved in deionized water). Fluorescing organic matter was better adsorbed than UV absorbance at 254 nm (UV 254) and dissolved organic carbon (DOC) in all tested water. Furthermore, highest adsorption of DOM (in terms of DOC, UV 254 and fluorescence) was observed during wastewater filtration. UV absorbing DOM had fast and similar breakthrough in surface water and synthetic water, whereas fluorescence breakthrough was very rapid only in synthetic water. PARAFAC modeling showed that different fluorescing components were differently adsorbed during GAC process. Particularly, fluorescing components with maxima intensity at higher excitation wavelengths, which are corresponding to humic-like fluorescence substances, were better removed than other components in all waters. As opposed to DOM, EOCs were better adsorbed during synthetic water filtration, whereas the fastest EOCs breakthrough was observed during filtration of wastewater, which was the water that determined the highest carbon fouling. Exception was represented by long-chained perfluoroalkylated substances (i.e., PFOA, PFDA and PFOS). Indeed, adsorption of these compounds resulted independent of water quality. In this study was also investigated the applicability of UV 254 and fluorescing PARAFAC components to act as surrogates in predicting EOCs removal by GAC in different water matrices. Empirical linear correlation for the investigated EOCs were determined with UV 254 and fluorescing components in all water qualities. However, fluorescence measurements resulted more sensitive than UV 254 to predict EOC breakthrough during GAC adsorption. When the data from all water qualities was combined, good correlations between the microbial humic-like PARAFAC component and EOC removals were still observed and they resulted independent of water quality if considering only real water matrices (wastewater and surface water). On the contrary, correlations between EOC removals and UV 254 removals were independent of water quality when combining data of surface waters and synthetic water, but a different correlation model was needed to predict EOCs breakthrough in wastewater. Graphical abstract Image 1 Highlights • Different DOM components are differently adsorbed in GAC filters. • Wastewater DOM was better adsorbed than surface water DOM. • Wastewater DOM determined the lowest adsorption of EOCs during GAC filtration. • Different correlation models were needed to monitor EOCs when using UV absorbance. • EOCs prediction by PARAFAC component was independent of water quality for real water. [ABSTRACT FROM AUTHOR]

Abstract Forty-seven precipitation samples were collected between March 2011 and May 2012 in Xiamen, southeastern China to examine the concentration, bioavailability and depositional flux of dissolved organic matter (DOM) in rainwater. Fluorescence excitation-emission (EEM) spectra of DOM were also determined to trace compositional changes during biodegradation experiments to assess which components of the DOM pool are biolabile. Rainwater dissolved organic carbon (DOC) concentrations ranged from 8.5 to 932 μM, with a volume-weighted average concentration of 128 μM. The fraction of biolabile DOC (BDOC%) ranged from 16 to 91% with an average of 46 ± 17%. The biodegradation rate of rainwater DOC followed a first-order exponential curve. During biodegradation experiments, protein-like fluorescence decreased and humic-like fluorescence remained constant or increased. Both DOC and BDOC concentration showed a dilution effect in relation to rainfall amount. Rainwater with continental trajectories typically had higher DOC concentrations than from marine trajectories, while, in contrast, the BDOC% didn't show significant differences among trajectories. Winter rainwater DOC concentration was significantly higher, while BDOC% was lower than other seasons, which may be related to greater relative fossil fuel inputs, particularly from coal burning in northern China. The depositional flux of rainwater DOC into Xiamen Bay was estimated to be 2.1 Gg C yr−1, and the rainwater BDOC flux to Xiamen Bay was approximately 35% of that discharged from the Jiulong River. Our results highlight that precipitation inputs play a significant role in supplying BDOC to the ocean with ramifications for marine food webs. Highlights • Rainwater BDOC% was high (~50%) in southeastern China. • Rainwater DOC concentration was influenced by dilution effects, air mass source and seasonality. • Rainwater BDOC% showed high values derived from both terrestrial and maritime sources. [ABSTRACT FROM AUTHOR]

• Polymer and commercial MP-DOM were characterized by FT-ICR-MS and EEM-PARAFAC. • The amount and composition of photo-induced MP-DOM is highly dependent upon organic additives. • Polymer MP-DOM contains abundant unsaturated organic fractions with humic-like fluorescence. • Fluorescence indicators can serve as the surrogate for molecular-level composition. The environmental occurrence and impact of dissolved organic matter leached from microplastics (MP-DOM) has been the subject of increased research interest. Commercial plastics, which typically contain additives, are subject to natural weathering processes and can eventually lose their additives. However, the effects of organic additives in commercial microplastics (MPs) on the release of MP-DOM under UV irradiation remain poorly understood. In this study, four polymer MPs (polyethylene; PE, polypropylene; PP, polystyrene; PS, polyvinylchloride; PVC) and four commercial MPs, including a PE zip bag, a PP facial mask, a PVC sheet, Styrofoam, were subjected to leaching under UV irradiation, and the MP-DOM was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC). Although UV light promoted the leaching of MP-DOM from both MP groups, the amount released was more pronounced for the polymer MPs than for the commercial MPs. The commercial MP-DOM was characterized by a prominent protein/phenol-like component (C1), while a humic-like component (C2) prevailed in the polymer MPs. FT-ICR-MS identified a higher number of unique molecular formulas for the commercial than for the polymer MP-DOM. The unique molecular formulas of commercial MP-DOM included known organic additives and other breakdown products, while the polymer MP-DOM featured more pronounced unsaturated carbon structures in its identified unique formulas. Several molecular-level parameters showed significant correlations with fluorescence properties, such as CHO formulas (%) with C1 and condensed aromatic structure (CAS-like, %) with C2, suggesting the potential application of fluorescent components as an optical descriptor for the complex molecular-level composition. This study also revealed the possible high environmental reactivity of both polymer MPs and fully weathered plastics due to the unsaturated structures generated in sunlit environments. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • High-rate fluidized MIEX minimize size of the reactor. • MIEX pretreatment double RO membrane lifetime. • Protein-like DOM mainly contributed to RO fouling. • MIEX preferentially removed more oxygenated DOM features. • MIEX remove unsaturated or longer chain DOM with a longer contact time. Biofouling is one of the most serious problems in reverse osmosis (RO) operations. Here, we operated a pilot-scale MIEX® system with a high-rate configuration as a pretreatment for an RO system in a water purification plant. The goal was to investigate the RO foulants obtained with and without pretreatment by MIEX®. The MIEX® resin (10 to 300 mL/L) removed dissolved organic matter (DOM) within 5 min. A pilot-scale fluidized reactor with 100 mL/L of MIEX® removed 35.6%, 49.4%, and 56.2% of dissolved organic carbon (DOC) for effective resin doses of 0.03, 0.06, and 0.12 mL/L, respectively. Unknown screening analysis by Orbitrap mass spectrometry revealed that the MIEX® pretreatment decreased or removed 165–363 DOM features with carbon, hydrogen, and oxygen (CHO features) and 145–220 CHO features with N heteroatoms (CHON features) with effective resin doses of 0.03–0.12 mL/L. Moreover, fluorescence EEM revealed the preferential removal of terrestrial DOM, resulting in over half of the protein-like substances remaining in the RO feed. MIEX® selectively removed highly oxygenated DOM features within a short contact time, while condensed aromatic structures and lignin-like compounds were removed after 30 min. Increasing the MIEX® dose resulted in the additional removal of DOM features with less oxygenated characters and longer alkyl chains. The RO system with and without MIEX® pretreatment was similarly fouled by protein-like substances and CHON features; however, the MIEX® pretreatment decreased CHO features and terrestrial DOM foulants. The MIEX® pretreatment decreased organic and irreversible fouling and doubled the RO system lifetime, resulting in lower chemical cleaning and pressure requirements for an identical permeate volume. [ABSTRACT FROM AUTHOR]

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Background: Phytocannabinoids naturally occur in the cannabis plant ( Cannabis sativa ), and Δ 9 -tetrahydrocannabinol (THC) and cannabidiol (CBD) predominate. There is a need for rapid inexpensive methods to quantify total THC (for statutory definition) and THC-CBD ratio (for classification into three chemotypes). This study explores the capabilities of a spectroscopic technique that combines ultraviolet-visible and fluorescence, absorbance-transmittance excitation emission matrix (A-TEEM). Methods: The A-TEEM technique classifies 49 dry flower extracts into three C. sativa chemotypes, and quantifies the total THC-CBD ratio, using validated gas chromatography (GC)-flame ionization (FID) and High-Performance Liquid Chromatography (HPLC) methods for reference. Multivariate methods used are principal components analysis for a chemotype classification, extreme gradient boost (XGB) discriminant analysis (DA) to classify unknown samples by chemotype, and XGB regression to quantify total THC and CBD content using GC-FID and HPLC data on the same samples. Results: The A-TEEM technique provides robust classification of C. sativa samples, predicting chemotype classification, defined by THC-CBD content, of unknown samples with 100% accuracy. In addition, A-TEEM can quantify total THC and CBD levels relevant to statutory determination, with limit of quantifications (LOQs) of 0.061% (THC) and 0.059% (CBD), and high cross-validation (>0.99) and prediction (>0.99), using a GC-FID method for reference data; and LOQs of 0.026% (THC) and 0.080% (CBD) with high cross-validation (>0.98) and prediction (>0.98), using an HPLC method for reference data. A-TEEM is highly predictive in separately quantifying acid and neutral forms of THC and CBD with HPLC reference data. Conclusions: The A-TEEM technique provides a sensitive method for the qualitative and quantitative characterization of the major cannabinoids in solution, with LOQs comparable with GC-FID and HPLC, and high values of cross-validation and prediction. As a spectroscopic technique, it is rapid, with data acquisition <45 sec per measurement; sample preparation is simple, requiring only solvent extraction. A-TEEM has the sensitivity to resolve and quantify cannabinoids in solution based on their unique spectral characteristics. Discrimination of legal and illegal chemotypes can be rapidly verified using XGB DA, and quantitation of statutory levels of total THC and total CBD comparable with GC-FID and HPLC can be obtained using XBD regression.

In carbonate aquifers, dissolved organic carbon from the surface drives heterotrophic metabolism, generating CO in the subsurface. Although this has been a proposed mechanism for enhanced dissolution at the water table, respiration rates and their controlling factors have not been widely evaluated. This study investigates the composition and concentration of dissolved organic carbon (DOC) reaching the water table from different recharge pathways on a subtropical carbonate island using a combination of DOC concentration measurements, fluorescence and absorption characterisation. In addition, direct measurements of the microbial response to the differing water types were made. Interactions of rainfall with the vegetation, via throughfall and stemflow, increase the concentration of DOC. The highest DOC concentrations are associated with stemflow, overland recharge and dissolution hole waters which interact with bark lignin and exhibit strong terrestrial-derived characteristics. The groundwater samples exhibit the lowest concentrations of DOC and are comprised of refractory humic-like organic matter. The heterotrophic response seems to be controlled by the concentration of DOC in the sample. The terrestrially sourced humic-like matter in the stemflow and dissolution hole samples was highly labile, thus increasing the amount of biologically produced CO to drive dissolution. Based on the calculated respiration rates, microbial activity could enhance carbonate dissolution, increasing porosity generation by a maximum of 1 % kyr at the top of the freshwater lens. [ABSTRACT FROM AUTHOR]

Rising organic matter concentrations in surface waters in many Nordic countries require current drinking water treatment processes to be adapted. Accordingly, the use of a novel nanofiltration (NF) membrane was studied during a nine month period in pilot scale at a large drinking water treatment plant in Stockholm, Sweden. A chemically resistant hollow-fibre NF membrane was fed with full scale process water from a rapid sand filter after aluminum sulfate coagulation. The combined coagulation and NF process removed more than 90% of the incoming lake water dissolved organic carbon (DOC) (8.7 mg C L −1 ), and 96% of the absorbance at 254 nm (A254) (0.28 cm −1 incoming absorbance). Including granulated active carbon GAC) filter, the complete pilot plant treatment process we observed decreases in DOC concentration (8.7–0.5 mg C L −1 ), SUVA (3.1–1.7 mg −1 L m −1 ), and the average nominal molecular mass (670–440 Da). Meanwhile, water hardness was practically unaffected (<20% reduction). Humic substances (HS) and biopolymers were almost completely eliminated (6510–140 and 260 to 10 μg C L −1 respectively) and low molecular weight (LMW) neutrals decreased substantially (880–190 μg C L −1 ). Differential excitation emission matrices (EEMs), which illustrate the removal of fluorescing organic matter (FDOM) over a range of excitation and emission wavelengths, demonstrate that coagulation removed 35 ± 2% of protein-like material and 65 ± 2% of longer emission wavelength, humic-like FDOM. The subsequent NF treatment was somewhat less selective but still preferentially targeted humic-like FDOM (83 ± 1%) to a larger extent than protein-like material (66 ± 3%). The high selectivity of organic matter during coagulation compared to NF separation was confirmed from analyses with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and liquid chromatography with organic carbon detection (LC-OCD), as coagulation exclusively targeted oxidized organic matter components while NF removed both chemically reduced and oxidized components. DOC removal and change in DOC character in the GAC filters showed marked differences with slower saturation and more pronounced shifts in DOC character using NF as pre-treatment. Fluorescence derived parameters showed a similar decrease over time of GAC performance for the first 150 days but also indicated ongoing change of DOM character in the post NF GAC filtrate over time even after LC-OCD indicated steady state with respect to outgoing carbon. During our trial iron concentrations were low (<30 ppb) and thus A254 could be directly related to the concentration of HS (R 2 = 0.9). The fluorescence derived freshness index (β:α) proved to be an excellent variable for estimating the fraction of HS present in all samples. Given the recommended limit of 4 mg L −1 for chemical oxygen demand (COD) for Swedish drinking water, coagulation will need to be supplemented with one or more treatment steps irrespective whether climate change will lead to drier or wetter conditions in order to maintain sufficient DOC removal with the current increasing concentrations in raw waters. [ABSTRACT FROM AUTHOR]

Dissolved organic carbon (DOC) and optical properties (absorption and fluorescence) of chromophoric dissolved organic matter (CDOM) were measured in October 2012, at the Arno river mouth and in a coastal station close to it. The data reported indicates that the Arno river represents an important source of DOC and CDOM to this coastal area, with a total DOC flux of 11.23–12.04·10 9 g C·y − 1 . Moving from the river to the sea, CDOM absorption and fluorescence decreased, while the spectral slope increased, suggesting a change in the molecular properties of CDOM. Mineralization experiments were carried out in order to investigate the main processes of DOM removal and/or transformation in riverine and coastal water. DOC removal rates were 20 μM·month − 1 in the river and 3 μM·month − 1 in the seawater, while CDOM was released during the first 30 days and removed in the following 40 days. [ABSTRACT FROM AUTHOR]

Abstract: Fluorescence excitation–emission matrix (EEM) approach together with principal component analysis (PCA) was used for assessing hydraulically irreversible fouling of three pilot-scale ultrafiltration (UF) systems containing full-scale and bench-scale hollow fiber membrane modules in drinking water treatment. These systems were operated for at least three months with extensive cycles of permeation, combination of back-pulsing and scouring and chemical cleaning. The principal component (PC) scores generated from the PCA of the fluorescence EEMs were found to be related to humic substances (HS), protein-like and colloidal/particulate matter content. PC scores of HS- and protein-like matter of the UF feed water, when considered separately, showed reasonably good correlations with the rate of hydraulically irreversible fouling for long-term UF operations. In contrast, comparatively weaker correlations for PC scores of colloidal/particulate matter and the rate of hydraulically irreversible fouling were obtained for all UF systems. Since, individual correlations could not fully explain the evolution of the rate of irreversible fouling, multi-linear regression models were developed to relate the combined effect of HS-like, protein-like and colloidal/particulate matter PC scores to the rate of hydraulically irreversible fouling for each specific UF system. These multi-linear regression models revealed significant individual and combined contribution of HS- and protein-like matter to the rate of hydraulically irreversible fouling, with protein-like matter generally showing the greatest contribution. The contribution of colloidal/particulate matter to the rate of hydraulically irreversible fouling was not as significant. The addition of polyaluminum chloride, as coagulant, to UF feed appeared to have a positive impact in reducing hydraulically irreversible fouling by these constituents. The proposed approach has applications in quantifying the individual and synergistic contribution of major natural water constituents to the rate of hydraulically irreversible membrane fouling and shows potential for controlling UF irreversible fouling in the production of drinking water. [Copyright &y& Elsevier]

Highlights: [•] Phytoremediation can reduce organic pollution in brackish environments. [•] EEM-PARAFAC can trace DOM dynamics during the phytoremediation process. [•] Sesuvium portulacastrum removed DOC, CDOM and certain EEM fluorophores. [•] The rhizosphere plays an important role in phytoremediation. [Copyright &y& Elsevier]

Improved techniques are required for the detection of inadvertent cross-connections between recycled water and potable water systems in dual reticulation schemes. The aim of this research was to assess the potential for fluorescence spectroscopy to be developed as a tool to distinguish recycled water from potable water. Weekly grab samples of recycled and potable water were obtained over 12 weeks from within an Australian dual reticulation site and analysed for fluorescence excitation-emission matrix (EEM), dissolved organic carbon (DOC), electrical conductivity (EC), and pH. Probabilistic techniques including distribution function fitting and Monte Carlo simulation were used to assess the ability to distinguish between recycled water and potable water sample pairs and the reliability of doing so. Fluorescence EEM spectroscopy was determined to be the most effective for the reliable differentiation by monitoring the protein-like fluorescence at peak T1—an excitation-emission wavelength pair of λex/em = 300/350 nm. While EC could distinguish between recycled and potable water, it was shown to be less sensitive and less reliable than peak T1 fluorescence. [ABSTRACT FROM AUTHOR]

A rapid, highly sensitive method for detection of cross-connections between recycled and potable water in dual reticulation systems is required. The aim of this research was to determine the potential of fluorescence spectroscopy as a monitoring tool at three Australian dual distribution (drinking and recycled water) systems. Weekly grab samples of recycled and potable water were obtained over 12 weeks at each site and analysed for fluorescence excitation-emission matrix (EEM) spectroscopy, UV254, dissolved organic carbon (DOC), electrical conductivity and pH. Fluorescence EEM spectroscopy was able to differentiate between recycled and potable water at each site by monitoring the protein-like fluorescence at peak T—an excitation-emission wavelength pair of λex/em = 300/350 nm. While electrical conductivity was also able to distinguish between recycled and potable water, the differentiation was greatest when using fluorescence. For example, the peak T fluorescence in recycled water was up to 10 times that of potable water in comparison with electrical conductivity that had a maximum 5 times differentiation. Furthermore, by comparing the protein-like fluorescence at peak T and humic-like fluorescence at peak A (λex/em = 235/426 nm), the three different recycled water systems were able to be differentiated. Overall, fluorescence shows promise as a monitoring tool for detecting cross-connections. [ABSTRACT FROM AUTHOR]

Parallel factor (PARAFAC) analysis was applied to the fluorescence excitation–emission matrices (EEM) of a water treatment plant's source and coagulated water during a peak chlorinated byproduct formation period. Water plant operations included the use of surface water only and surface/ground water mixtures. Three statistically significant components were obtained through PARAFAC analysis and were correlated to dissolved organic carbon (DOC), chlorine consumption, and individual disinfection byproduct (DBP) formation potential. Multifactor linear regression of select component scores showed linear relationships to individual chloro-DBP compounds providing insight to possible precursor locations within the EEM and organic matter, as well as, organic compound characteristics responsible for chloro-DBP formation. Likewise, linear relationships were also observed between component scores and empirically estimated precursor concentration methods reported in the literature. These results suggest PARAFAC analysis of EEM may be an effective tool for monitoring source water, measuring treatment process effectiveness (removal of specific DBP precursor), and estimating DBP precursor concentrations and individual DBP compound formation potential. [ABSTRACT FROM AUTHOR]

Direct nanofiltration and nanofiltration combined with powdered activated carbon known as the PAC/NF process were tested regarding the removal of effluent organic matter for reclamation of tertiary effluent from a municipal wastewater treatment plant. They can be regarded as a promising treatment alternative for high quality water reuse applications, especially for direct injection. The total removal for DOC was above 90% with permeate concentrations below 0.5 mg/l. Size exclusion chromatography and fluorescence EEM proved to trace origin of the organic matter even in low concentration ranges. The type and dosage of adsorbent influences the process performance significantly and allows process optimization. [ABSTRACT FROM AUTHOR]

The fluorescence excitation–emission matrix (EEM) technique coupled with parallel factor (PARAFAC) modeling and measurements of bulk organic carbon and other optical properties were used to characterize the oil components released from the Deepwater Horizon oil spill in the Gulf of Mexico and to examine the chemical evolution and transformation of oil in the water column. Seawater samples were collected from the Gulf of Mexico during October 2010 and October 2011, three months and fifteen months, respectively, after the oil spill was stopped. Together with previous results from samples collected during the oil spill in May/June 2010, these time series samples allow us to elucidate changes in the optical properties of dissolved organic matter (DOM) from the time of maximum oil impact to its recovery, 15 months after the spill. Although the oil had profoundly altered the optical properties of the DOM in the entire water column during the oil spill, naturally occurring DOM became predominant in surface waters by October 2010, three months after the spill. Anomalous DOM with high optical yields, however, still resided in deep waters even 15 months after the oil spill in October 2011, showing a persistent influence of the oil in deep waters. Based on fluorescence EEM data and PARAFAC modeling, three oil components and one natural humic-like DOM could be readily identified. The most prominent oil component had its maximum fluorescence intensity at Ex/Em 224/328 nm, and the other two centered on Ex/Em 264/324 and 232/346 nm, respectively. The humic-like DOM component had its wide emission peak from 390 to 460 nm over the excitation wavelength at ∼248 nm. We hypothesized that component-2 (264/324 nm) was mostly derived from photochemical degradation and the component-3 (232/346 nm) could be a degradation product from both microbial and photochemical degradation, although both C2 and C3 are subject to degradation at different rates. The oil component ratios, such as C2/C1 and C3/C1, were closely related to degradation states of oil and can be used as a sensitive index to track the fate, transport and transformation of oil in the water column.

• Removal of 28 micropollutants and fluorescence EEM indexes was investigated. • 7 fluorescence EEM indexes specific to adsorption were found using PARAFAC analysis. • Correlations were found between the removal of spectroscopic indexes and most OMPs. • UV 254 provided much less accurate correlations than most fluorescence indexes. • OMPs interactions with fluorescing DOM likely promoted their co-adsorption. Monitoring the removal of organic micropollutants (OMPs) in advanced wastewater treatment facilities requires expensive and time-consuming analytical methods that cannot be installed online. Spectroscopic techniques such as fluorescence excitation/emission spectroscopy were demonstrated to offer the potential for monitoring OMPs removal in conventional wastewater treatment plants or ozonation pilots but their application to activated carbon (AC) adsorption processes was only investigated at lab scale and not in real treatment facilities. In this study, indexes from fluorescence emission/excitation matrices (EEMs) were used to find correlations with the removal of 28 OMPs from a large-scale AC pilot in fluidized bed employed for wastewater advanced treatment, as well as from batch experiments. Differences in OMPs removal could be observed depending on the operational conditions (i.e. pilot or batch experiments, contact time, type of AC) and the physico-chemical properties of the molecules. 7 PARAFAC components were derived from the fluorescence EEMs of 60 samples obtained before and after adsorption. Positive correlations were obtained between the removal of fluorescence indexes and most OMPs, and correlation coefficients were much higher than the ones obtained with UV 254 , confirming the interesting potential of fluorescence spectroscopy to accurately monitor adsorption performances at the industrial scale. The highest correlation coefficients were obtained for OMPs having the best removals while the ones that were refractory to adsorption, as well as to interactions with DOM, exhibited weak correlations. These results suggest that interactions between OMPs and fluorescing DOM and their subsequent co-adsorption onto AC were at the origin of the correlations found. Lower correlations were also found for the most biodegradable OMPs, which indicated that the occurrence of biological effects could make the monitoring of these compounds more challenging. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Every year, the harvesting of Eucalyptus generates a large amount of abandoned Eucalyptus leaves (ELs), which may release dissolved organic matter (DOM) when immersed in water. If these substances are carried by surface runoff directly to the source of drinking water, some components in the DOM tend to form disinfection byproducts (DBPs) within the water-supply system, posing risk to human health. In this study, the characteristics of DOM released from leaves of Eucalyptus urophylla were studied and the potential of DBPs formation of the EL-released DOM during the chlorination process was investigated. The results showed that the EL-released DOM was mainly composed of small molecules and hydrophobic substances. Of the total EL-released DOM, the proportion with molecular weight less than 10 kDa accounted for over 80% and the hydrophobic substances took up over 62%. The DOM showed strong absorbance at UV 254 and the fluorescence response corresponding to humic acid-like (HA-like) fractions, soluble microbial byproduct-like, aromatic protein and fulvic acid-like (FA-like) material, which have been considered to be related to the potential precursors of chlorinated DBPs. Non-targeted screening demonstrated the presence of phenolics, carbohydrates, and amino acids. The analysis of products generated in chlorination process revealed the formation of trichloromethane (TCM) and the total organic halogen (TOX). The present study fully confirms that the DOM released from Eucalyptus urophylla leaves has great potential for the generation of chlorinated DBPs. Image 1 • EL-released DOM was mainly composed of small molecules and hydrophobic substances. • The DOM showed strong absorbance at UV 254 and identified fluorescence response. • Non-targeted screening demonstrated the presence of phenolics and amino acids. • Products generated in chlorination process revealed the formation of TCM and TOX. • EL-released DOM has great potential for the generation of chlorinated DBPs. [ABSTRACT FROM AUTHOR]