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Refinery effluents represent an emission source of hydrocarbons (HCs) and other constituents to the environment. Thus, characterisation of effluent quality in terms of concentrations of key parameters relative to permitted standards is important and for total petroleum hydrocarbons (TPH), the specific composition of the HC mixture can affect its toxicity to aquatic organisms. Therefore, this study was designed to analyse TPH, benzene, toluene, ethyl benzene, xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), (bio) chemical oxygen demand, total nitrogen, total suspended solids and selected metals before, and after, treatment steps to demonstrate removal efficiencies across 13 refineries with variable wastewater treatment systems. Final discharge concentrations of the measured parameters were by 97% within the so called Best Available Technique Associated Emission Levels (BAT-AELs). Further, TPH composition was characterised using high-resolution two-dimensional gas chromatography (GCxGC) analysis to understand the mass distribution by carbon number and specific chemical class. Measurements were compared to SimpleTreat model predictions for validation. SimpleTreat successfully predicted the shape of the effluent composition since it is essentially a removal constant applied to the influent composition. The predictions were of similar magnitude as, or were greater than, the effluent concentrations since SimpleTreat is based on typical performance and is intended to be conservative. This was especially true for aromatic constituents. Reduction in potential HC exposures also coincided with a decrease in predicted toxicity using a mechanistic oil toxicity model, PETROTOX. Overall, the results indicate that EU petroleum refineries are likely to achieve a high performance level regarding effluent treatment.

Nowadays concern exists about the safety for both football players and the environment of recycled tire rubber used as infill in synthetic turf football pitches. In this study 40 target compounds, including polycyclic aromatic hydrocarbons (PAHs), plasticizers, antioxidants and vulcanization agents were determined in 50 synthetic football pitches of diverse characteristics to estimate environmental risks. This is the first study of crumb rubber sport facilities in Portugal. Analyses were performed by ultrasound-assisted extraction followed by gas chromatography-tandem mass spectrometry (UAE-GC-MS/MS). To evaluate the transfer of the target chemicals from the crumb rubber to the runoff water, water leachates collected from several football pitches were analyzed by solid-phase microextraction (SPME-GC-MS/MS). In addition, lab-scale runoff simulation experiments were performed to assess whether a persistent inflow of the target compounds from the football pitches into the runoff water wcould exist. Results revealed the presence of most of the target PAHs in crumb rubber at total concentrations up to 57 μg g−1, next to a high number of plasticizers and vulcanization agents. Runoff water collected from the football pitches contained up to 13 PAHs as well as other chemicals of environmental concern. In addition, continuous leaching of chemicals from the crumb rubber to the surrounding water was demonstrated. The transfer of target chemicals into the runoff water poses a potential risk for the aquatic environment.

Polychlorinated dioxins and dibenzofurans (PCDD/Fs) are highly toxic contaminants that are strictly regulated and monitored in the environment and food to reduce human exposure. Recently, the increasing occurrence of polybrominated dioxins and dibenzofurans (PBDD/Fs) in the environment is raising concerns about the impact on human health by the combined exposure to chlorinated and brominated analogues of dioxins. Toxicological properties of PBDD/Fs relative to PCDD/Fs have not been firmly established, and brominated dioxins are not included in routine monitoring programs. In this study, we set out to determine human-relevant congener-specific potency values for a range of brominated and chlorinated dioxin congeners, based on their aryl hydrocarbon receptor (AhR)-mediated mode of toxic action. Transactivation of the AhR was measured using dioxin-responsive (DR) CALUX reporter gene assays. Because of known species-differences in dioxin-mediated toxicity, we developed and used a HepG2 human liver cell-based DR human CALUX assay that is a variant of the rodent-based DR CALUX. The assay was found to be highly inducible and stable, with low variations between independent measurements. Using both DR CALUX assays in an automated high-throughput mode we found that overall PBDD/Fs were as potent as PCDD/Fs in inducing AhR transactivation, but congener-specific differences were observed. We also observed species-specific differences in sensitivity and potency when comparing DR human REP values to those obtained in the rat-based DR CALUX. Finally, we observed significant differences between WHO-TEF values and DR human REP values, suggesting that actual WHO-TEF values may underestimate the hazards associated with exposure of humans to dioxins.

This paper presents the results of the research on the influence of catalytic activity of iron(II) octacarboxyphthalocyanines (FePcOC) on the transformation of diclofenac (DCF) which is the most popular anti-inflammatory analgesic. Diclofenac poses a serious threat to the natural environment. The paper demonstrates that diclofenac, in the presence a monomeric form of iron octacarboxyphthalocyanine and hydroxyl radicals (HO•) (from H2O2), undergoes a transformation into diclofenac-2,5-iminoquinone (DCF-2,5-IQ), causing distinct changes in the UV–Vis absorption spectrum. In the presence of iron octacarboxyphthalocyanine and H2O2, the previously colourless diclofenac solution becomes intense orange. As a result, a new band at approx. 450 nm appears in the absorption spectrum. HPLC analysis has shown that the concentration of diclofenac decreases with time. TD-DFT calculations using the CAM-B3LYP/6-31+G (d, p) method have been conducted to confirm experimental data concerning the formation of a new band at λmax = 450 nm.

The stenohaline zebra mussel, Dreissena polymorpha, is uniquely sensitive to the ionic composition of its aquatic environment. Waterborne copper (Cu) uptake and accumulation in zebra mussels were examined at various conditions in an environmentally relevant range in freshwater, i.e. Cu exposure levels (nominal concentrations of 25 and 50 μg/L), pH (5.8-8.3), and sodium (Na+) concentrations (up to 4.0 mM). Copper accumulation was simulated by a kinetic model covering two compartments, the gills and the remaining tissues. The Cu uptake rate constant decreased with decreasing pH from 8.3 down to 6.5, indicating interactions between H+ and Cu at uptake sites. The kinetic simulation showed dose-dependent effects of Na+ on Cu uptake. At 25 μg/L Cu, addition of Na+ at 0.5 mM significantly inhibited the Cu uptake rate, while no significant differences were found in the uptake rate upon further addition of Na+ up to a concentration of 4.0 mM. At 50 μg/L Cu, the Cu uptake rate was not influenced by Na+ addition. Calibration results exhibited dose-dependent elimination rates with more profound elimination with increasing exposure levels. With kinetic parameters calibrated at environmentally relevant conditions, in terms of pH and Na+ concentrations, the model performed well in predicting Cu accumulation based on independent data sets. Estimates of the Cu concentration in mussels were within a factor of 2 of the measurements. This demonstrates potential application of kinetic models that are calibrated in environmentally relevant freshwater conditions.

Agricultural, industrial and household chemicals are emitted in large rivers along populated areas, transported by water and deposited in sediments, posing (eco)toxicological risks. Sediments have received less attention than surface waters, likely because of the intrinsic complexity of interactions between sediment constituents complicating correct framing of exposures. Sadly, thorough assessment of the in situ behavior of sediment constituents in bioassays is often not practical. Alternatively, we related physicochemical properties of sediments from field testing to results from bioassays. The case study covers Flemish sediment (incl. Scheldt and Meuse) and mortality of Hyalella azteca, a sensitive bio-indicator. Though variable across Flanders’ main water bodies, heavy metals and ammoniacal nitrogen dominate the observed toxicity according to toxic unit (TU) assessments. Depending on the water body we explain between 50 and 90% of the variance in the observed H. azteca mortality, substantially more than previous ecotoxicity studies. We attribute the remaining variance to potential incoherently documented biophysicochemical sediment properties and concentrations of non-target biocides, testing conditions/set-ups and/or species variabilities. We discuss the relative influence of heavy metals/metaloxides, nitrogen (e.g. fertilizer), polycyclic aromatics and organochlorides. We highlight both direct and indirect mortality mechanisms. We note potential synergetic mixture effects between ammoniacal nitrogen and chromium. Such synergy may be phenomenological of ‘standard’ aerobic bioassays, and prove a complementary method alongside the ‘acid-volatile sulfide test’ to more effectively link concentration to toxicity. Future study ought to include variation in biophysicochemical properties between sampling locations and batch bioassays. Our approach enables water managers to interpret their monitoring data by converting sediment concentrations to H. azteca mortality and prioritize substances that contribute most.

Toddlers are at increased risk of dust ingestion and subsequently flame retardant (FR) exposure because they often play close to the floor and mouth hands and objects. Exposure to some FRs have been associated to endocrine disruption and neurodevelopmental disorders. Previous research has shown higher FR concentrations in toddlers’ serum and urine, but which toddler-behaviors influence exposure levels remains to be determined. We investigated how toddler-behaviors are associated to FRs in hand wipes (HWs) and saliva. Fifty 8-18 month-old children from the Linking EDCs in maternal Nutrition to Child health study, were visited at home. The child’s behavior was observed and assessed using a questionnaire. Hand-to-object behavior frequency was associated with HW tris(chloroethyl) phosphate (TCEP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), tris(phenyl) phosphate, tris(methylphenyl) phosphate, and resorcinol bis(diphenyl phosphate) levels above the detection limit. Children playing with electronics multiple times per week had higher TDCIPP HW levels compared to children playing with electronics once per month or never (p = 0.032 and p = 0.046). Frequent mouth-to-object and frequent mouthing a pacifier were associated with lower TDCIPP (p = 0.019) and tris(2-chloroisopropyl) phosphate (TCIPP) HW levels, respectively (p = 0.002–0.019). Exposure estimates based on hand-to-mouth behavior did not exceed the available reference doses. This is the first study investigating toddler-behavior in relation to FR hand loadings. Although a range of behaviors was investigated, only a few showed a relation with FR HW levels, suggesting that toddler-behavior might not alone be responsible for the elevated FR levels in children. It is therefore important to explore other pathways including dermal absorption and inhalation.

Given the extent to which per- and polyfluoroalkyl substances (PFAS) are used in commercial and industrial applications, the need to evaluate treatment options that reduce environmental emissions and human and ecological exposures of PFAS is becoming more necessary. One specific chemical class of PFAS, fluorotelomer alcohols (FTOHs), have vapor pressures such that a significant fraction is expected to be present in the gas-phase even at ambient temperatures. FTOHs are used in a variety of PFAS applications, including synthesis and material coatings. Using two complementary mass spectrometric methods, the use of calcium oxide (CaO) was examined as a low temperature and potentially low-cost thermal treatment media for removal and destruction of four gas-phase FTOHs of varying molecular weights. This was accomplished by assessing the removal/destruction efficiency of the FTOHs and the formation of fluorinated byproducts as a function of treatment temperature (200–800 °C) in the presence of CaO compared to thermal-only destruction. During the treatment process, there is evidence that other PFAS compounds are produced at low temperatures (200–600 °C) as the primary FTOH partially degrades. At temperatures above 600 °C, thermal treatment with CaO prevented the formation or removed nearly all these secondary products.

Bisphenol A (BPA)-free plastic products are widely available. Transient BPA release has been reported in Tritan drinking bottles. This study assessed the effectiveness of common consumer washing methods in removing BPA contamination in Tritan bottles using both ELISA and HPLC-MS/MS assays. BPA release was detected in 2 out of 10 kinds of Tritan drinking bottles tested. Average BPA level was 0.493 μg/L in water samples from a type of Tritan kid drinking bottle following 24-h incubation at room temperature, corresponding to a release rate of 0.015 ng/cm2/h. Of the common consumer cleaning methods identified in an informal survey, dishwashing was the most effective method that significantly reduced, even eliminated BPA release from the tested BPA-positive Tritan bottles, while rinsing with water and handwashing with soap and water were ineffective. The bioactivity of the leached BPA was confirmed using a rodent cardiac myocyte acute exposure model and an invertebrate 7-day exposure model. The BPA release is possibly the result of surface contamination in the manufacturing process. As a case study, our result may be informative for general consumer practice and for better quality control by the manufactures.

The burden of the human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) infection has transformed the African continent into a major consumer of antiretrovirals (ARVs) drugs. In addition to HIV burden, the African continent has also a high incidence of tuberculosis (TB) and has been experiencing recurring outbreaks of several other viral, bacterial, and parasitic epidemic diseases. The novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2 or Covid-19) pandemic outbreak is adding to the continent’s infectious diseases burden as experts are predicting that it will be here for a long time. One of the consequences of these infectious diseases is that antiviral and antibiotic compounds have become some of the most consumed pharmaceuticals on the continent. Many of these drugs have been frequently detected in surface waters across Africa. There is limited information available on the adverse effects of the mixtures of different types of pharmaceuticals in African aquatic environments on fish reproduction. The present study investigated the effects of the ARV drug nevirapine (NVP - 1.48 and 3.74 μg/L) and its mixture with the antibiotic sulfamethoxazole (3.68 μg/L) and trimethoprim (0.87 μg/L) on O. mossambicus gonads using histopathological endpoints as biomarkers. The fish (n = 52) were exposed for 30 days in a static renewal system. Female O. mossambicus exposed to nevirapine (3.74 μg/L) and to NVP – antibiotic mixture recorded higher ovary indices. Statistically significant differences were found in female ovary indices between the fish exposed to NVP (3.74 μg/L) and the control fish (p = 0.002) as well as between the fish exposed to the NVP - antibiotic mixture and the control fish (p = 0.009). The main observed histopathological changes in the ovaries were increased vitellogenic oocyte atresia and vacuolation of the interstitial tissue in the fish exposed to NVP - antibiotic mixture. It is evident that the presence of NVP - antibiotics mixture in water triggered the observed histopathology in female fish ovaries. The detected abnormal high rate of atretic oocytes could result in impaired fish reproduction., Graphical abstract Image 1

Ammonia is a known environmental pollutant around the world. It leads to the deterioration of air quality and has adverse effects on human health. Although previous studies have demonstrated that ammonia caused some health problems to chickens, it is still unclear whether ammonia causes cardiac toxicity. The functional autophagy is very important for cardiac homeostasis. Therefore, the role of autophagy was investigated in the mechanism of chicken heart damage induced by environmental contaminant ammonia in our present study. The results from the oxidative stress index (SOD, GPx, H2O2, and MDA), NO content, iNOS activity, and transmission electron microscopy indicated that excess ammonia induced oxidative stress and autophagy in the chicken heart. The expression results from miR-202-5p and PTEN/AKT/mTOR (PTEN, LC3-I, LC3-II, p-AKT, AKT, Beclin1, Dynein, ATG5, p-mTOR and mTOR) signaling pathway-related genes further confirmed that excess ammonia induced cardiac autophagy. In conclusion, these results demonstrated that excess ammonia can cause cardiac damage and mediate mir-202-5p to regulate autophagy through PTEN/AKT/mTOR pathway in the chicken heart injury. Our findings will provide a new insight for better assessing the toxicity mechanism of environmental pollutants ammonia on the heart.

Given the ubiquity of iodinated disinfection by-products (I-DBPs) in drinking water and their prominent toxicity, it is of vital significance to evaluate I-DBPs toxicity and explore the underlying mechanism. The toxicity of iodoacetic acid (IAA), a typical type of I-DBPs, might be linked with oxidative stress. However, it remains unknown for the response of antioxidant enzyme superoxide dismutase (SOD) in the mouse primary hepatocytes when exposed to IAA and the underlying mechanism. This study explored SOD response to IAA and the underlying mechanisms at the molecular and cellular levels. Under IAA exposure, the observed increase of SOD activity in the hepatocytes was caused by the increase of SOD production via ROS stimulation and the increase of SOD molecular activity. Molecular experiments showed that IAA binds to SOD molecule mainly via electrostatic forces with one binding site around the active site and six binding sites in the surface of protein. The binding interaction leads to the conformational changes of SOD and the disruption of protein aggregates. This work could offer basic data for the comprehensive understanding of the adverse effects of IAA and references for assessing the harmful effects of DBPs.

A modified cellulose acetate, modified chitosan, titanium dioxide membrane (MCA-MCS-TiO2) was prepared for oil-water emulsion separation and Cu(II) adsorption. This membrane shows excellent hydrophilicity and underwater oleophobicity. After being modified, the water contact angles of the membranes attain 13.7°, and the underwater oil contact angles reach 157.24°. The membrane exhibits high oil-water separation efficiency (99.4%) for cyclohexane, at the same time, the adsorption amount of Cu(II) on the membrane was measured. The variables include the ratio of modified cellulose to modified chitosan, the initial concentration of Cu(II), and the pH of Cu(II) solution. When pH = 7, the adsorption capacity of the membrane to Cu(II) reaches 220.67 mg g−1. When the concentration of Cu(II) solution is 1000 mg L−1, the adsorption efficiency is as high as 97.0%.

Background Fine particulate matter (PM2.5) exposure has been proved to be associated with respiratory diseases in epidemiological studies, but the underlying mechanisms are not clear. One of the most important mechanisms involved is inflammation. Non-coding RNAs are proposed to play crucial roles in epigenetic modulation and post-transcriptional regulation. Identification of non-coding RNAs can show us the new insight into the molecular toxicity of PM2.5. Materials and methods Intra-tracheal instillation of saline or PM2.5 was performed in BALB/c Mice once a week for consecutive eight weeks. Genomewide transcriptome profiling of coding genes, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) in mice lung were done by ribosomal RNA-depleted RNA sequencing. Lung histological alternations were observed in haematoxylin and eosin (HE) staining sections. The expressions of pro-inflammatory cytokines and Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome were quantified by qRT-PCR、ELISA and Western blot. Results 1873 coding genes, 885 lncRNAs and 142 circRNAs were differentially expressed in lung tissues of the saline and PM2.5 exposed mice. The upregulated expressions of lncRNA NONMMUT065867, lncRNA NONMMUT064312, lncRNA NONMMUT018123 and the downregulated expressions of circRNA CBT15_circR_1011, circRNA mm9_circ_005915 were identified by qRT-PCR in PM2.5 group. The pulmonary inflammation score was higher in PM2.5 group. What’s more, the expressions of pro-inflammatory cytokines and NLRP3 inflammasome were upregulated in PM2.5 exposed mice. Conclusion PM2.5 causes lung inflammation and increases the expression of NLRP3 inflammasome. The identified novel lncRNAs and circRNAs may paly important role in the development of lung inflammation caused by PM2.5.

The potential of a mixed sorbent consisting of vermicompost and Persian charred dolomite for simultaneous adsorption of Basic Violet 16 (BV16) and Reactive Red 195 (RR195) was investigated. First-order derivative spectrophotometry was used for simultaneous analysis of the two dyes. In single dye experiments, the maximum adsorption capacity of vermicompost for BV16 was found to be 16 mg g−1 and the adsorption capacity of charred dolomite for RR195 was 7.3 mg g−1. Anionic RR195 was not noticeably adsorbed by vermicompost (negative surface charge) and cationic BV16 not by charred dolomite (positive surface charge) but adsorbed by the oppositely charged adsorbents which indicates a selective electrostatic adsorption mechanism. In binary dye solution, BV16 adsorption onto charred dolomite was increased in the presence of RR195 (synergistic effect), yet RR195 adsorption on charred dolomite was not influenced by BV16. An antagonistic effect of RR195 was concluded for BV16 adsorption onto vermicompost. The adsorption equilibrium data for both adsorbents fitted more acceptable to the Langmuir isotherm model than to the Freundlich model in single and binary solutions, but other than the adsorption of BV16 on vermicompost in binary solution which followed the Freundlich model. More than 50% of the removal efficiencies determined for both dyes onto the mixed sorbents were >70% which highlights that the mixed sorbent investigated is highly efficacious for the simultaneous removal of cationic and anionic dyes from contaminated groundwater. Eight cycles reusing vermicompost with 1 N NaOH for regeneration demonstrates the practicability and economic advantage of this natural biosorbent.

The toxicity of polychlorinated biphenyls (PCBs) and their transformation have been intensively investigated in recent years. However, the potential mechanisms of biotransformation in a lake food web remain unclear. To explore the correlation between the PCBs and δ 15 N values or FAs, six fish species were collected from Dongting Lake, and various tissues were dissected to analyze the δ 15 N values, FAs and PCBs. Based on the wet weight (ww), the concentration of ∑PCBs 115 ranged from 0.04 to 9.77 ng g −1 , and the highest level was found in the gonad of Cyprinus carpio . The toxicity equivalent (TEQ) of PCBs ranged from 0.003 to 2.39 pg g −1 , and the highest level was found in the fat of Silurus asotusy . The PCB levels in fish collected from Dongting Lake were at the low end of the global range. PCB28, 52, 95, 99, 101, 105 110, 118, 138, 153, 155 and 209 were found in all tissues. PCBs were distributed in a tissue-specific and species-specific manner in fish. PCB153 and 138 had a positive correlation with the TEQ in liver, gill, intestine and skin of fish on the basis of lipid weight (lw). Docosahexaenoic acid/eicosapentaenoic acid (DHA/EPA) and polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) had a positive correlation with some PCB congeners in the intestine. PCB52, ∑tetra-PCBs and Ind-PCBs had a positive correlation with the δ 15 N values in liver of fish on the basis of ww. PUFA/SFA and DHA/EPA might be indicators for the transfer of PCB congeners.

This study examined the kinetics of the binding of Al(III) ions by natural organic matter (NOM) exemplified by Suwannee River humic acid (SRHA). This processes was studied for a 5–8 pH range and environmentally relevant concentrations of the system components. Al(III)-NOM interactions were quantified using differential absorbance spectra whose intensity and shape depended on pH and reaction time. In all cases the differential spectra had four bands with maxima located at 245, 275, 320, 380 nm. These bands were assigned to the engagement of the carboxylic-like and/or phenolic-like groups, as well as electrostatic gel in NOM. Several parameters of the absorbance spectra (e.g., spectral slopes of log-transformed spectra in wavelength range 260–270 and 350–400 nm, ΔS260-270 and ΔS350-400 respectively) were linearly correlated (R2 = 0.98) with concentrations of carboxylic-like groups and total NOM-bound Al(III) ions predicted based on the NICA-Donnan model. The binding of Al(III) ion by NOM at all pHs was modeled assuming the presence of three kinetically distinct sites. This study demonstrates that differential absorbance spectroscopy can be used to quantify the kinetics and mechanisms of NOM-metal ions interactions and monitor them in practically important system including water treatment operations.

Bioremediation is an emerging and sustainable technique that can either occur naturally or be enhanced by introducing nutrients or bacteria able to degrade specific contaminants. In this study, the efficiencies of natural attenuation with nutrients, and bioaugmentation with nutrients and a consortium of five exogenous bacteria, were evaluated for total petroleum hydrocarbon (TPH) degradation in five highly contaminated soils from China, and Kuwait. The bioaugmentation treatment exhibited better efficiencies than the natural attenuation, and reached 48.10% of TPH degradation with a half-life of 41.76 d. The addition of exogenous bacteria also increased the removal of TPH in the highest contaminated soil sample. The concentration of TPH in that soil was reduced from 236, 500 mg kg −1 of dry soil to 176, 566 mg kg −1 of dry soil in 40 d, which was equivalent to 25.4% degradation of TPH. The degradation rate (1501.8 mg kg −1 d −1 of TPH) was higher than those reported in previous studies with a lower concentration of TPH. The bioaugmented strains could withstand high concentrations of TPH and thrive in five different types of soils. Consequently, these strains can be used to remediate soils that are heavily contaminated with petroleum hydrocarbons.

The porous graphitic carbon nitride nanosheets (PCNSs) with high yields were synthesized by using one–step chemical exfoliation method. PCNSs accelerated separation efficiency of photo-generated electron−hole pairs in comparison to bulk graphitic carbon nitride. The PCNS5 (exfoliation for 5 h) exhibited optimal photocatalytic disinfection capability towards Escherichia coli K-12 under simulated solar light irradiation with complete disinfection of 6.5 log10 cfu/mL of E. coil K-12 within 2 h. The enhanced photocatalytic activity of PCNS5 originated from mesoporous nanosheet structure. The possible mechanism of photocatalytic disinfection has proposed that intracellular reactive oxygen species levels and the activities of antioxidant enzymes (e.g., catalase and superoxide dismutase) were enhanced. Transmission electron microscope images observed during photocatalytic disinfection process suggested that the cell membrane was regarded as the first target for oxidation, resulting in a faster leakage of cytoplasmic content and finally degradation of DNA leading to bacterial death. Furthermore, the trapping experiment showed that superoxide radical (•O2−) and holes (h+) were responsible for E. coli K-12 disinfection by PCNS5.

In this study, Fe3O4/Co3O4 composites were prepared and applied in the catalytic ozonation of sulfamethoxazole (SMX). Various parameters including initial solution pH, Fe3O4/Co3O4 composites dose, O3 dose and SMX concentration were investigated. Results showed that Fe3O4/Co3O4 composites could significantly improve the mineralization of SMX by catalytic ozonation system and a synergic effect between Fe3O4 and Co3O4 was observed. Only about 16% total organic carbon (TOC) could be removed in 60 min by single ozonation under the condition of 20 mg/L SMX, 6.0 mg/min O3, pH 5.1 and room temperature, While in the presence of 0.10 g/L Fe3O4/Co3O4 composites at the same conditions, 60% TOC removal were obtained by catalytic ozonation process. SMX could be degradation by O3 rapidly and the removal was not significantly affected by the changing parameters. However, those operating parameters exerted different effects on SMX mineralization. Furthermore, the generation of hydroxyl radicals (OH) and the utilization efficiency of O3 would increase with the addition of Fe3O4/Co3O4 composites. The quenching experiments indicated that OH might account for the enhancement of SMX mineralization and the mechanism of catalytic ozonation was proposed. Additionally, the intermediates were detected by using a high-performance liquid chromatography-mass spectrometry (LC-MS), from which some plausible transformation pathways were proposed.

The performances of distinct BDD anodes (boron doping of 100, 500 and 2500 ppm, with sp3/sp2 carbon ratios of 215, 325, and 284, respectively) in the electrochemical degradation of ciprofloxacin – CIP (0.5 L of 50 mg L−1 in 0.10 M Na2SO4, at 25 °C) were comparatively assessed using a recirculating flow system with a filter-press reactor. Performance was assessed by monitoring the CIP and total organic carbon (TOC) concentrations, oxidation intermediates, and antimicrobial activity against Escherichia coli as a function of electrolysis time. CIP removal was strongly affected by the solution pH (kept fixed), flow conditions, and current density; similar trends were obtained independently of the BDD anode used, but the BDD100 anode yielded the best results. Enhanced mass transport was achieved at a low flow rate by promoting the solution turbulence within the reactor. The fastest complete CIP removal (within 20 min) was attained at j = 30 mA cm−2, pH = 10.0, and qV = 2.5 L min−1 + bypass turbulence promotion. TOC removal was practically accomplished only after 10 h of electrolysis, with quite similar performances by the distinct BDD anodes. Five initial oxidation intermediates were identified (263 ≤ m/z ≤ 348), whereas only two terminal oxidation intermediates were detected (oxamic and formic acids). The antimicrobial activity of the electrolyzed CIP solution was almost completely removed within 10 h of electrolysis. The characteristics of the BDD anodes only had a marked effect on the CIP removal rate (best performance by the least-doped anode), contrasting with other data in the literature.

Advanced organic characterisation methods were used to investigate the suitability of lab-based model compounds as surrogates to mimic the dissolved organic matter (DOM) of both first and second generation fermentation industry effluents. Comparisons to both humic acid and synthetic melanoidin revealed the limitations of using these model organic compounds in treatment studies of biorefinery effluent. Rapid resin fractionation (RRF) of effluent from yeast cultivated on molasses suggests that 64% of the dissolved organic matter is present in the form of very hydrophobic acid (VHPhoA) compounds. Molecular weight distribution by size exclusion chromatography (LC-OCND) and fluorophore specific intensity by fluorescence excitation and emission matrix (FEEM) of the yeast effluent was comparable to signatures from humic acid. This indicates that humic acid would be a suitable model compound for oxidation, adsorption and filtration studies. Differences among the fermentation industry effluents were found to be inherently dependent on both the biochemistry of yeast and processes used. RRF and FEEM spectra of effluent from bioethanol production on cellulosic feed highlighted a preponderance of neutral compounds with fluorophore specific intensity characteristic of non-humic compounds with a higher fraction of neutral compounds (41%) relative to VHPhoA (38%), SHPhoA (16%) and HPhi (5%) moieties. Findings were not consistent with commercial humics, synthetic melanoidins or other cellulosic and lignocellulosic based effluents from Kraft and Thermomechanical pulp mills since the actual pollutants are heavily dependent on the pre-treatment process. This suggests further work is required to develop a model compound for treatment studies of effluent from second generation bio-refineries.

An emerging class of unregulated disinfection byproducts, halobenzoquinones (HBQs), has gained recent interest following suggestions of enhanced toxicity compared to regulated disinfection byproducts. While the kinetics of HBQ hydrolysis in water have been well characterized, the stability of HBQs in cell culture media, a critical parameter when evaluating toxicity in vitro, has been overlooked. The objective of this study was: (1) to contrast the stability of a prevalent HBQ, 2,6-dichloro-1,4-benzoquinone (DCBQ), in cell culture media and water, and (2) to evaluate the cytotoxicity of parent and transformed DCBQ compounds as well as the ability of these compounds to generate intracellular reactive oxygen species (ROS) in normal human colon cells (CCD 841 CoN) and human liver cancer cells (HepG2). The half-life of DCBQ in cell media was found to be less than 40 min, compared to 7.2 h in water at pH 7. DCBQ induced a concentration-dependent decrease in cell viability and increase in ROS production in both cell lines. The parent DCBQ compound was found to induce significantly greater cytotoxicity compared to transformed DCBQ products. We demonstrate that the study design used by most published studies (i.e., extended exposure periods) has led to a potential underestimation of the cytotoxicity of HBQs by evaluating the toxicological profile primarily of transformed HBQs, rather than corresponding parent compounds. Future in vitro toxicological studies should account for HBQ stability in media to evaluate the acute cytotoxicity of parent HBQs.

Batch-type experiments were used to study adsorption-desorption of three sulfonamides: sulfadiazine (SDZ) sulfachloropyridazine (SCP), and sulfamethazine (SMT), in five crop soils, whereas laboratory soil column experiments were employed to obtain data on transport processes. Adsorption results were satisfactorily adjusted to Linear and Feundlich equations, with R2 values above 0.95. Adsorption followed the sequence SDZ < SMT < SCP, showing higher values for soils with higher levels of organic carbon (OC) content. Conversely, desorption was higher in soils with less OC, and lower in soils with higher OC contents. The temporal moment analysis method gave values for the transport parameters τ and R which were significantly correlated with soil parameters related to organic matter, specifically OC and N concentrations. The higher retention of the three sulfonamides in soils with high organic matter content is a relevant fact, with value when programming management practices in agricultural soils, and specifically in relation to the spreading of animal manures, slurries, or waste containing these emerging pollutants.

Phenolic compounds are problematic byproducts generated from lignocellulose pretreatment. In this study, the feasibility degradation of syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) by Bio-Electro-Fenton (BEF) system with a novel Fe–Mn/graphite felt (Fe–Mn/GF) composite cathode were investigated. The nano-scale Fe–Mn multivalent composite catalyst with core shell structure distributed more evenly on GF surface to form a catalyst layer with higher oxygen reduction reaction performance. Accordingly, the maximum power density generated with Fe–Mn/GF cathode was 48.1% and 238.9% higher than Fe/GF and GF respectively, which further enhanced the in situ generation of H2O2 due to the superiority of nano-scale core shell structure and synergistic effect of Fe and Mn species. The degradation efficiency of the three phenolic compounds in the BEF system could reached 100% after optimization of influencing parameters. Furthermore, a possible SA degradation pathway by BEF process in the present system was proposed based on the detected intermediates. These results demonstrated an efficient approach for the degradation of phenolic compounds derived from lignocellulose hydrolysates.

Sodium Dodecyl Benzene Sulfonate (SDBS) is a major anionic surfactant and is widely used in the detergent industry. The large amount of SDBS discharged into water bodies can cause eutrophication of water bodies and produce toxic effects in aquatic organisms. In this study, the degradation of SDBS and variation in toxicity during the plasma treatment process were evaluated using gas-liquid interface discharge. The experimental results showed that SDBS could be removed effectively after discharge for 8 min at an initial concentration of 30 mg/L. The SDBS removal could be fitted by the first-order kinetic model. The plasma voltage and initial pH had great effects on the removal of SDBS. At the same voltage, SDBS could be removed faster under alkaline conditions. Compared to ozonation, much higher SDBS and TOC removal performance was achieved by plasma treatment. HO, which was mainly derived from the reaction of H2O2 and ozone in the solutions, played a major role in the oxidation process. The toxicity evaluation showed that plasma treatment could reduce the acute toxicity effectively initially, and also indicated that the formed intermediates of formate, oxalate, malonate and sulfate had no negative effects. However, further treatment caused an increase in toxicity, which was mainly correlated with the excessive residual H2O2 formed during the plasma process. This study indicated that while applying plasma treatment, the conditions should be optimized comprehensively to maintain a low H2O2 residual in the effluent.

As the exposure of organisms to contaminants can provoke harmful effects, some organisms try to avoid a continuous exposure by using different strategies. The aim of the current study was to assess the ability of the shrimp Palaemon varians to detect a triclosan gradient and escape to less contaminated areas. Two multi-compartmented exposure systems (the linear system and the HeMHAS-Heterogeneous Multi-Habitat Assay System) were used and then results were compared. Finally, it was aimed how sensitive the avoidance response is by comparing it with other endpoints through a sensitivity profile by biological groups and the species sensitive distribution. The distribution of the shrimps along the triclosan gradient was dependent on the concentrations, not exceeding 3% for 54 μg/L in the linear system and 7% for 81 μg/L in the HeMHAS; 25% of organisms preferred the compartment with the lowest concentrations in both systems. Half of the population seems to avoid concentrations around 40–50 μg/L. The triclosan concentration that might start (threshold) to trigger an important avoidance (around 20%) was estimated to be of 18 μg/L. The profile of sensitivity to triclosan showed that avoidance by shrimps was less sensitive than microalgae growth and avoidance by guppy; however, it might occur even at concentrations considered safe for more than 95% of the species. In summary, (i) the HeMHAS proved to be a suitable system to simulate heterogeneous contamination scenarios, (ii) triclosan triggered the avoidance response in P. varians, and (iii) the avoidance was very sensitive compared to other ecotoxicological responses., C.V.M. Araújo is grateful to the Spanish Ministry of Science, Innovation and Universities for the Juan de la Cierva (IJCI-2014-19318) and Ramón and Cajal (RYC-2017-22324) contracts. M. Hampel benefits from a Ramón and Cajal contract (RYC-2012-12217) from the Spanish Ministry for Economy and Competitiveness. This study was funded by the Spanish Ministry of Science, Innovation and Universities, Spain (Explora Project: #CGL2017-92160-EXP) and the Ministry for Economy and Competitiveness in the framework of the project HORACIO (CTM2015-70731-R).

Silkworm (Bombyx mori) is one of the most important economic insects in the world, while pesticides impact its economic benefits. Tebuconazole is a fungicide that has been frequently detected in agriculture systems at concentrations that affect endocrine function in organisms. In the present study, silkworm larvae at different instar stages were exposed to tebuconazole, respectively. Cocoon weight, cocoon shell weight and cocoon shell rate were significantly decreased by 6.8%, 11.8% and 4.4% respectively, after exposure to 0.40 mg/L tebuconazole at 2nd -3rd instar stage. Vacuolization was found in the exposure silkworm under histopathological study at all stages exposures, indicating potential damage to silk gland. Downregulation of genes transcription (Fibh, Fibl, P25, Ser2, Ser3) involved with protein synthesis in the silk gland were further observed, and the results showed significant decreasing in mRNA expression among the tebuconazole treatments. Ecdysteroid levels in silkworm were changed with pronounced decreases after exposed to tebuconazole. In contrast, exposure to tebuconazole significantly increased juvenile hormone 1 concentrations and the maximum increasing fold of juvenile hormone 1 was up to 3.73 which was observed at stage I exposure. In addition, co-exposure to 2 and 10 mg/L forskolin able to mitigate tebuconazole-induced downregulate of mRNA expression of Sgf1 in the present study, indicating the potential mechanism of tebuconazole-induced chronic toxicity in silkworm may relative to PI3K/AKT/TORC1/Sgf1 pathway.

Studies have been conducted on the genotoxicity and carcinogenicity of disinfection by-products formed from natural organic matter (NOM) and mitigation effect for mutagens and clastogens by NOM. Whereas, reportedly, synthetic humic acid in high concentration has induced genotoxicity in human cells, and NOM samples have provoked mild oxidative and other physiological responses in aquatic organisms. Our group developed a novel detection method for DNA damage formation, namely enhanced green fluorescent protein (EGFP)-fused mediator of DNA damage checkpoint 1 (MDC1)-expressing human cells as simple and high-sensitive system. By using this method, a significant increase in the foci area was observed after 3 h, but not 24 h for 130 mgC L−1 Suwannee River fulvic acid (SRFA), 38 mgC L−1 humic acid (SRHA), and 19 mgC L−1 NOM (SRNOM). The SRNOM concentration is the original environmental one; therefore, it was suggested that the formation and repair of DNA damage associated with γ-H2AX, a biomarker for DNA double-strand breaks by mild oxidative stress, in Suwannee River (SR) were detected for the first time. The increase in the foci area was not observed for 18 mgC L−1 Lake Biwa fulvic acid (LBFA) and 50 mg L−1 catechin after both 3 h and 24 h. The difference between the SR and Lake Biwa (LB) samples may result from the differences in their electron-accepting capacity. The application of this methodology is expected to elucidate oxidative stress and toxicological effects shortly and in detail for many water samples.

Magnetic carbon nanotube (MCNT) composites with titanium dioxide (TiO2) have an enhanced photocatalytic disinfection efficiency (i.e. higher disinfection rate) and better applicability (i.e. solar light applicability and catalyst separation using its magnetic property) than bare TiO2 and/or MCNT. However, the role and mechanism of MCNT in the disinfection process are still unclear. Therefore, this study aimed at investigating the disinfection mechanism of Escherichia coli using MCNT-TiO2 nanocomposites under various conditions (i.e. the presence and absence of light and reactive oxygen species scavengers, and different MCNT-TiO2 ratio) and photocatalytic disinfection models. The results showed that (i) MCNT and its nanocomposites with TiO2 had much higher disinfection efficiencies than bare TiO2, (ii) the physical bacterial capture was the dominant disinfection mechanism, (iii) the higher disinfection rate was found at an optimum MCNT:TiO2 ratio of 5:1 under the tested experimental conditions, (iv) hydroxyl radical (OH) was the influencing reactive oxygen species on the photocatalytic disinfection using MCNT-TiO2, and (v) good correlation between experimental parameters (i.e. carbon contents, surface area and concentration of MCNT-TiO2) and the contribution rate of physical and photocatalysis reactions. The finding from this study and the methods proposed herein are essential for understanding the photocatalytic disinfection processes using TiO2 and its carbonaceous nanocomposites, which can promote the application of photocatalytic disinfection process.

Bioelectrochemical systems (BESs) are known to enhance the remediation of hydrocarbon-contaminated soil and sediments compared with natural attenuation, and the primary mechanism has been assumed as anaerobic degradation facilitated by electroactive bacteria (EAB) using the electrode as electron acceptor. However, known EAB were rarely found on the anodes of reported BESs, which challenged the fundamental mechanism of BESs although significant current generation was always observed during degradation of these recalcitrant substrates. This study however found the abundant EAB Geobacter (∼27.3%) in the anodic biofilms, which confirmed the role of electroactive bio-anode on the conversion of hydrocarbons into the current for the enhancement of remediation. Widespread occurrence of aerobic hydrocarbon-degrading bacteria (HDB) (e.g. ∼24.0% Parvibaculum and ∼30.6% Pseudomonas) was observed in soils with limited dissolved oxygen (∼0.4 mg/L). The higher abundance of dehydrogenase genes was found in the anode biofilms than that in soils, indicating anodic microorganisms may be mainly responsible for the removal of intermediates of aerobic hydrocarbons degradation in soils. High water saturation level and sandy soil texture showed positive impacts on bioelectrochemical remediation, while clay soil and unsaturation condition pose challenges in mass transfers in the matrix. The reactor performance was consistent with the phylogenetic molecular ecological network (pMENs) analysis, which showed that sandy soil BESs had tighter microbial network interactions than clay soil reactors.

Biochar is an adsorbent widely used to remove contaminants from polluted water. A series of biochar from corn straw, corncob and corn starch was prepared through one-step pyrolysis. The biochar was characterized, and the capacity for triazine pesticide (TRZ) removal from water was compared. P doped biochar from corn straw (CSWP) was able to remove six TRZs (>96%) from water after shaking five times. The removal was more rapid than that by four other commonly used adsorbents. The physicochemical properties of CSWP were characterized systematically, and carboxyl and metaphosphates on CSWP were found to provide adsorption sites. The experimental data were best fitted by a pseudo-second-order kinetic model and the Freundlich model. Adsorption equilibrium of atrazine on CSWP occurred within 20 min, and the maximum adsorption capacity reached up to 79.6 mg g−1 at 25 °C. The adsorption mechanism of CSWP for atrazine includes Van der Waals' forces, hydrogen bonding, electrostatic interactions and pore filling. CSWP can be reused at least five times and shows strong potential as a candidate for the rapid and efficient removal of TRZs.

Perfluoroalkyl substances (PFAS) and organochlorine pesticides (OCPs) in surface sediments were investigated from the Bering Sea, the Chukchi Sea and adjacent Arctic Ocean in 2010. Total concentrations (dry weight) of Σ14PFAS in surface sediments (0.85 ± 0.22 ng g−1) of the Bering Sea were lower than that in the Chukchi Sea and adjacent Arctic Ocean (1.27 ± 0.53 ng g−1). Perfluoro-butanoic acid (PFBS) and perfluoro-octanoic acid (PFOA) were the dominant PFAS in these areas. The concentrations of Σ15OCPs in the sediment of the Bering Sea (13.00 ± 6.17 ng g−1) was slightly higher than that in the Chukchi and Arctic Ocean (12.05 ± 2.27 ng g−1). The most abundant OCPs were hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane (DDT) and its metabolites. The composition patterns of HCHs and DDTs indicated that they were mainly derived from the early residues via river runoff. Increasing trends of PFAS, HCHs and DDTs in surface sediments from the Bering Sea to the Arctic Ocean were found, indicating oceanic transport. In summary, the concentrations of OCPs were orders of magnitude greater than the observed PFAS concentrations, and the concentrations of PFAS and OCPs in surface sediments from the Bering Sea to the Chukchi Sea and adjacent Arctic Ocean are at the low to moderate levels by comparing with other coastal and marine sediments worldwide.

Polycyclic aromatic compounds (PACs) possess toxicity towards humans, and their presence in the environment is unwanted. Polar transformation products (TPs) are more mobile, and can be considered emerging contaminants, as they represent a more bioavailable carrier of the same toxic properties. Acidic TPs has been proposed as an important class of polar TPs. This study presents a tiered analytical approach to investigate acidic and polar PAC TPs in environmental conditions. The tiered approach exploits target analysis for quantification of acids; suspect screening for tentative identification based on retention time and spectral matching using databases; and finally non-target analysis based on chromatography and data independent broadband MS to highlight potentially unknown analyte peaks. The approach includes a mixed-mode anion exchange solid phase extraction (MAX-SPE) to fractionate neutral and acidic compounds, and is applied to three cases: I) Photo-oxidation of six PACs generated suspected hydroxylated-, carbonylated- and carboxylated PACs but also proposed the presence of mono- and dicarboxylic acids, which have not been reported elsewhere. For a subset of four acids, conversion rates were determined. II) Recovery of spiked acids from diesel spilled harbor water was 80% by LC-MS, and diesel spill weathering was evaluated from the neutral fraction by GC-MS. III) By non-target analysis sulfonated PACs, presumable derived from photo-oxidation, were detected in run-off basins of an arctic landfarm, alongside hypothesized naturally occuring fatty acids. The tiered approach is a sensitive and versatile tool to extract information on PACs and their polar TPs from polluted environmental sites.

Arsenic exposure disturbs brain development in humans. Although developmental neurotoxicity (DNT) of arsenic has been studied in vivo and in vitro, its mode-of-action (MoA) is not completely understood. Here, we characterize the adverse neurodevelopmental effects of sodium arsenite on developing human and rat neural progenitor cells (hNPC, rNPC). Moreover, we analyze the involvement of reactive oxygen species (ROS) and the role of the glutathione (GSH)-dependent antioxidative defense for arsenite-induced DNT in a species-specific manner. We determined IC50 values for sodium arsenite-dependent (0.1–10 μM) inhibition of hNPC and rNPC migration (6.0 μM; >10 μM), neuronal (2.7 μM; 4.4 μM) and oligodendrocyte (1.1 μM; 2.0 μM) differentiation. ROS involvement was studied by quantifying the expression of ROS-regulated genes, measuring glutathione (GSH) levels, inhibiting GSH synthesis and co-exposing cells to the antioxidant N-acetylcysteine. Arsenite reduces NPC migration, neurogenesis and oligodendrogenesis of differentiating hNPC and rNPC at sub-cytotoxic concentrations. Species-specific arsenite cytotoxicity and induction of antioxidative gene expression is inversely related to GSH levels with rNPC possessing >3-fold the amount of GSH than hNPC. Inhibition of GSH synthesis increased the sensitivity towards arsenite in rNPC > hNPC. N-acetylcysteine antagonized arsenite-mediated induction of HMOX1 expression as well as reduction of neuronal and oligodendrocyte differentiation in hNPC suggesting involvement of oxidative stress in arsenite DNT. hNPC are more sensitive towards arsenite-induced neurodevelopmental toxicity than rNPC, probably due to their lower antioxidative defense capacities. This species-specific MoA data might be useful for adverse outcome pathway generation and future integrated risk assessment strategies concerning DNT.

Mesoporous Fe-Cu@SiO2 core-shell catalyst was synthesized and assessed for its catalytic activity in the ozonation of salicylic acid (SA). The synthesized catalyst was characterized by XRD, TEM, SEM, XPS, H2-TPR, etc. Fe-Cu@SiO2 exhibited a regular spherical shape and had the surface area at 1216 m2 g−1. The wrapping of metal components and their strong interaction prevented metal leaching. Fe-Cu@SiO2 showed the highest activity for SA mineralization when compared with Fe@SiO2 and Cu@SiO2. In Fe-Cu@SiO2/O3, 88% TOC was removed, which was 2.5 times as much as that in sole ozonation. SA degradation efficiency in Fe-Cu@SiO2/O3 increased with initial pH. O3, ·OH and H2O2 were the main reactive oxygen species accounting for SA mineralization. Due to their scavenging effect of ·OH, NH4+, NO3− and humic acids would inhibit the degradation efficiency of Fe-Cu@SiO2/O3. Acidic sites, oxygen vacancies and the Fe-Cu(I/II) electron transfer were responsible for ozone decomposition and ·OH generation. SA mineralization proceeded through the ·OH mechanism. Moreover, SA mineralization in O3 and Fe-Cu@SiO2/O3 both exhibited a two-stage pseudo first-order kinetics (stage I: 0–45 min; stage II: 45–120 min). The degradation intermediates were detected to investigate the reaction pathway. ORP and EEM were used to monitor the degradation process. Great difference was found for carboxylic acids accumulation in O3 and Fe-Cu@SiO2/O3. The accelerated removal of oxalic acid and humic acid-like intermediates were responsible for the two-stage pseudo first-order kinetics.

The incidence of antibiotic resistance genes (ARGs) in tap water leads to potential risks to human health and draws more and more attention from the public. However, ARGs harbored in drinking water remain largely unexplored. In this study, a simulated water supply system was designed to study the effects of different pipe flow rates on the transmission of antibiotic resistance in water supply systems. We observed that the biofilm in low flow rate pipeline (0.1 m/s, 0.3 m/s) had higher concentration of both antibiotic resistant bacteria (ARB) and ARGs, while high flow rate (0.5 m/s and 0.7 m/s) resulted in low relative abundance of ARB and high relative abundance of ARGs in biofilms. The results showed that the high flow rate led to an abundance in non-culturable bacteria and a scarcity of nutrients in the biofilm, giving rise to its antibiotic resistance. High-throughput sequencing pointed out that the high content of Caulobacteraceae and Paenibacillus were determined in biofilms of high flow rate pipelines. Similarity analysis of microbial community composition of inlet water (IW), biofilms and outlet water (OW) showed that the composition of microbial community in OW was more similar to that in biofilms than in IW. Genera of bacteria in biofilms and OW (Brevundimonas, Brevibacillus and Pseudomonas) which had relationship with sulⅠ, sulⅡ in biofilms (P 0.05) had higher relative abundance than that in IW. Different flow rate conditions had an impact on the biomass, microbial community, ARB and ARGs composition of biofilms. Thus, the detachment of biofilms can increased the antibiotic resistance of the water.

A high oxygen evolution potential (2.6V) and conductivity of Ti/TiO2 NTs/Ta2O5-PbO2 anode was fabricated by mixed metal oxide. A well-aligned TiO2 nanotubes was successfully prepared by using 1-butyl-3-methylimidazolium tetrafluoroborate as the electrolyte. The surface structure of anodes were characterized by scanning electron microscope, X-ray diffraction and energy dispersive X-ray spectroscopy. During the electrochemical degradation experiments, the effects of different anodes, current density, initial pH value and concentration were discussed. The results showed that co-doped Ta2O5 coating is an effective method to improve the surface morphology and the electrochemical characterization of Ti/TiO2 NTs/PbO2. At the initial pH value of 3 and current density of 12 mA cm−2, the removal rates of Acid Orange 7 and total organic carbon with Ti/TiO2 NTs/Ta2O5-PbO2 anode were almost 100% and 98.3%. Comparing with Ti/PbO2 anode at the same charge consumption (3 A h L−1), the instantaneous current efficiency of the Ti/TiO2 NTs/Ta2O5-PbO2 anode and Ti/TiO2 NTs/PbO2 anode increased by 40.0% and 27.1%, respectively. The highest rate of k.OH on Ti/TiO2 NTs/Ta2O5-PbO2 anode was 12.4 μmol (L min)−1. The organic dyes are oxidized into CO2 and H2O by .OH radical. The reaction process and mechanism during the electrochemical degradation were discussed.

Summarization: Tannery wastewater is characterized by high and variable concentrations of diverse pollutants, which makes it difficult and costly to treat. In the search for sustainable treatment options for tannery effluents, two pilot-scale horizontal subsurface flow (HSF) constructed wetlands (CW) were built and operated for the treatment of synthetic water of quality similar to that of pre-treated tannery effluents. Five different loading phases were examined with gradual increase of inflow COD, NH4+-N and Cr loads until reaching and exceeding the typical composition of a tannery effluent. High COD and NH4+-N removals were observed (82 and 96%, respectively), and almost complete Cr removal in the outflow, which met the Venezuela national standards for environmental discharge. Plant uptake was measured, but microbial processes appear to be the main ammonium transformation/removal mechanism. Nitrogen, chlorophyll and Cr in the plant aerial parts and roots indicated the capacity of Phragmites sp. to grow and survive even under high loads. The measured heterotrophic bacteria in the substrate and rhizomes indicated the biofilm development and the oxidation of organic matter and nitrogen. Water losses via evapotraspiration were also measured and reached 14%. Overall, the tested CW design proved to be a sustainable and feasible alternative for the treatment of tannery wastewater in tropical climates. Παρουσιάστηκε στο: Chemosphere

As yet, the effect of biodiesels on the emissions of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from heavy-duty diesel engines (HDDEs) has only been studied using limited fuel blend ratios. To clarify the influence of using higher fractions of biodiesel on the emissions of toxic organic pollutants from diesel engines, in this research, the emissions of PM, PAHs, and persistent organic pollutants (POPs) from EURO IV and EURO III HDDEs fueled by low to high waste cooking oil (WCO)-based biodiesel-petrodiesel fuel blends were studied, including D100 (0% biodiesel), B20 (20%), B40 (40%), B60 (60%), B80 (80%), and B100 (100%). The engines were tested according to the US FTP-75 test procedure. The results for the EURO IV diesel engine showed that the PM and toxic organic pollutant emissions were reduced with increases in the blending ratio up until the B60 scenario when compared to the D100 scenario. This is because biodiesel has higher oxygen content and no or lower aromatic content than petrodiesel. Nevertheless, during the B80 and B100 scenarios, the PM and toxic organic pollutant emissions increased due to the high viscosity property of biodiesel, which negatively affected the combustion process. The biodiesel effect on the emissions from EURO III engine was more pronounced because of its lower combustion efficiency, and therefore the improvement in combustion using biodiesel resulted in greater PCDD/F reductions.

The activation of oxygen (O2) under room condition is highly desirable for oxidative removal of organic pollutants in water. Herein, we report a graphite felt (GF)-supported α-MnO2 catalyst which is active for activating O2 with assistance of an anodic electric field. The electro-assisted catalytic wet air oxidation (ECWAO) process on MnO2/GF is able to rapidly degrade a variety of dyes, pharmaceutics and personal care products (PPCPs) under room condition. The congo red, basic fuchsin, neutral red and methylene blue are completely mineralized in 160 min, and the bisphenol A, triclosan and ciprofloxacin are mineralized by 89.9%, 81.5% and 65.4%, respectively, in 300 min. Mechanistic study indicates a surface-catalyzed non-free radical pathway for the oxidation of organic pollutants by O2 in the ECWAO process. The oxygen vacancies on MnO2 are identified as the catalytically active sites, at which oxygen atom is transferred from O2 to organic molecule through chemisorbed oxygen species. The anodic electric field assists such an oxygen transfer pathway by activating the complex of chemisorbed oxygen species and organic molecule through electro-oxidation reaction. The ECWAO process on MnO2/GF electrode exhibits a great potential for practical wastewater treatment under room condition.

To efficiently improve the performance of ultrafiltration (UF) membrane for drinking water treatment, carbon nanotubes (CNTs) and carbon nanofibers (CNFs) were utilized as pre-deposited coating layers on membrane surface. A comparative study between these two carbon nanomaterials for enhancing pollutants removal and mitigating membrane fouling induced by natural organic matter (NOM) was carried out. The surface morphologies were characterized by scanning electron microscopy, and the results indicated that the CNTs coating layer was more dense and homogeneous with a smaller pore size than that of CNFs. The removal and antifouling performance of CNTs/CNFs coated membranes were investigated with typical NOM, i.e., humic acid, bovine serum albumin, sodium alginate, as well as natural surface water. The results showed that the presence of coating layers was very effective to improve the rejection rate of NOM, among which CNTs exhibited significant better performance than CNFs. The fouling control performance was influenced by the NOM fraction and coating mass (6–50 g/m 2 ). Generally, CNTs coating layer was more efficient in alleviating both reversible and irreversible membrane fouling, while CNFs exhibited limited effect on irreversible fouling control. Both pre-adsorption and size exclusion contributed to the rejection of membrane foulants, thus reducing the organics directly contacted with the underlying membrane. In natural surface water treatment, the pre-deposited coating layers significantly delayed the transition of fouling mechanisms from pore blocking to cake filtration. The experimental results were expected to illustrate the feasibility of pre-deposited CNTs/CNFs layers for enhancing membrane performance during drinking water treatment.

© 2019 Elsevier Ltd The formation of toxic disinfection by-products during water disinfection due to the presence of bromide and iodide is a major concern. Current treatment technologies such as membrane, adsorption and electrochemical processes have been known to have limitations such as high energy demand and excessive chemical use. In this study, the selectivity between bromide and iodide, and their removal in membrane capacitive deionisation (MCDI) was evaluated. The results showed that iodide was more selectively removed over bromide from several binary feed waters containing bromide and iodide under various initial concentrations and applied voltages. Even in the presence of significant background concentration of sodium chloride, definite selectivity of iodide over bromide was observed. The high partial-charge transfer coefficient of iodide compared to bromide could be a feasible explanation for high iodide selectivity since both bromide and iodide have similar ionic charge and hydrated radius. The result also shows that MCDI can be a potential alternative for the removal of bromide and iodide during water treatment.

Nonylphenol (NP) is one widely distributed representative of environmental estrogens that disturb reproductive activities, bone metabolism and brain function through interfering diverse signal pathways leading to hormone metabolic dysfunctions, immunologic derangement, and tumorigenesis. Few of previous studies have observed the subacute toxicity on rodents, and little has been focused on the mechanism underneath the toxicities observed.The 32 male Sprague-Dawley (SD) rats were randomly divided into four groups, the negative control group (corn oil) NP low, medium and high dose groups [30, 90, 270 mg/(kg·d)]. SD rats administrated with different dosage of NP every other day for 28d. Elisa and RT-PCR was employed to observe estrogen metabolism markers or mRNA expressions.In serum, NP exposure caused testosterone (T) (p 0.001), progesterone (PROG) (p 0.05) and estrone (E1) (p 0.05) increased. In testicle, NP exposure caused T (p 0.001), PROG (p 0.05), E1 (p 0.05), 17β-estradiol (E2) (p 0.05) and ERα mRNA (p 0.01) increased, while P450 aromatizing enzyme (p 0.001) decreased in NPL and ERβ mRNA (p 0.001) decreased in NPM and NPH. In liver, NP exposure caused 17β-HSD2 mRNA (p 0.01) increased, while P450 aromatizing enzyme decreased (p 0.05).NP exposure exhibited general and estrogenic toxicity in rats through disturbing estrogen secretion network and estrogen receptor expression network, inducing abnormal metabolism of estrogen, whether in serum, liver and testicle.

Organic pesticides are one of the main environmental pollutants, and how to reduce their environmental risks is an important issue. In this contribution, we disclose the molecular basis for the resistance of American sloughgrass to aryloxyphenoxypropionic acid pesticides using site-directed mutagenesis and molecular modeling and then construct an effective screening model. The results indicated that the target-site mutation (Trp-1999-Leu) in acetyl-coenzyme A carboxylase (ACCase) can affect the effectiveness of the pesticides (clodinafop, fenoxaprop, cyhalofop, and metamifop), and the plant resistance to fenoxaprop, clodinafop, cyhalofop, and metamifop was found to be 564, 19.5, 10, and 0.19 times, respectively. The established computational models (i.e. wild-type/mutant ACCase models) could be used for rational screening and evaluation of the resistance to pesticides. The resistance induced by target gene mutation can markedly reduce the bioreactivity of the ACCase-clodinafop/fenoxaprop adducts, and the magnitudes are 10 and 102, respectively. Such event will seriously aggravate environmental pollution. However, the biological issue has no distinct effect on cyhalofop (RI＝10), and meanwhile it may markedly increase the bioefficacy of metamifop (RI＝0.19). We could selectively adopt the two chemicals so as to decrease the residual pesticides in the environment. Significantly, research findings from the computational screening models were found to be negatively correlated with the resistance level derived from the bioassay testing, suggesting that the screening models can be used to guide the usage of pesticides. Obviously, this story may shed novel insight on the reduction of environmental risks of pesticides and other organic pollutants.

In this study, the copper nanoparticles (Cu NPs) reactivity for degradation of the reactive dye black 5 (RP5), picric acid (PA) and 2,4-D herbicide was evaluated. The RP5 degradation occurred by oxidative via, through hydroxyl radicals generated in situ, with active participation of Cu(I) and H2O2. The use of catalase confirmed the hydrogen peroxide formation in situ. Reduction degradation via electron transfer was also possible. On the other hand, PA had low degradation efficiency (less than 20%) under any conditions studied (similar to those used for RP5). High degradation efficiency for 2,4-D was achieved by the association of the Cu NPs/H2O2. Thus, the behavioral model of Cu NPs has been proven. This behavioral difference of the chemical species to be degraded in relation to the behavior of the Cu NPs was studied, evaluating its redox behavior by voltammetric analyzes. This study aided in the understanding and selection of the chemical species that can be degraded by these NPs.

Polybrominated diphenylethers (PBDEs), hexabromocyclododecanes (HBCDDs) and tetrabromobisphenol A (TBBPA) were monitored in various foods from terrestrial and aquatic animal origin (>850 samples), collected in the Netherlands between 2009 and 2014. The terrestrial samples included meat/fat from 7 animal species (including bovines, pigs, broilers and sheep), bovine milk and hen eggs. Dominant PBDE congeners in these samples were BDE-47, -99, -100, -153 and -183. The meat/fat generally contained the highest ∑PBDE concentrations compared to eggs and milk, with meat from deer, horse and sheep containing the highest concentrations. Generally declining ∑PBDE concentrations were observed between 2009 and 2014, however, this was only significant in pig meat and hen's eggs. The aquatic samples included fillets from 18 species (including herring, haddock and salmon), brown crab parts, shrimp and mussels, and the highest ∑PBDE concentrations were seen in body parts of brown crab, herring, mackerel, salmon and sea bass (on wet weight basis). Patterns generally contained more congeners (i.e., BDE-28, -49 and -66) additional to the aforementioned congeners found in terrestrial samples. Herring, sea bass and brown crab (body parts) contained among the highest PBDE concentrations. TBBPA was only detected in 3 individual samples (bovine and broiler meat and haddock), while α-HBCDD was the dominant diastereomer detected in several terrestrial and aquatic samples. When detected, TBBPA and HBCDD concentrations were generally in the same order as ∑PBDE concentrations in the same sample types.

Pharmaceuticals are frequently detected in aquatic environments as mixtures and can cause toxic effects to non-target organisms. We aimed to evaluate the single and mixture effects of the pharmaceuticals metformin, bisoprolol, ranitidine and sotalol using Daphnia similis and Danio rerio. In addition, we aimed to test the predictive accuracy of the mathematical models concentration addition and independent action and to evaluate the nature of the possible toxicological interactions among these pharmaceuticals using the combination index-isobologram model. The acute toxicity of these four pharmaceuticals individually and of their binary mixtures were evaluated using the D. similis tests. Developmental and behavioral effects induced by the pharmaceuticals in quaternary mixtures were evaluated using D. rerio embryos. We observed that most of the binary mixture effects were in the zone between the effects predicted by the concentration addition and the independent action model. The combination index-isobologram model showed to be adequate to describe the nature of possible interactions occurring between the combined pharmaceuticals. Developmental and behavioral acute adverse effects seem not to be induced by the joint action of the quaternary mixture of the evaluated pharmaceuticals on D. rerio embryos, at the concentrations at which they are usually found in surface fresh waters. However, from the results obtained with D. similis, we can conclude that assessing the ecological risk based on the effects of individual pharmaceuticals can underestimate the risk level posed by these environmental contaminants.

A MBBR-MBR system has been developed with marine microorganisms enriched for saline wastewater treatment in this work, showing high COD and NH3–N removals. The behaviour of fouling-related components (EPS and SMP) has been studied as functions of operating time (40–90 days), salinity (0–30 g/L NaCl) and backflow ratio (0–300%, from MBR to MBBR). High biodegradability of the MBBR-MBR at optimal conditions can induce more biodegradation of humic acid-like (λex/λem: 350nm/430 nm) and fulvic acid-like (260nm/445 nm) molecules to soluble microbial by-product-like molecules (275nm/325 nm), reducing the membrane biofouling rate. The biodegradation process is suggested by the excitation-emission matrix (EEM) images. In the study of sudden salinity shock, results show that real-time monitoring the concentration of biofoulants is more effective (operative time extended by 60%) than monitoring the transmembrane pressure (operative time extended by 33%) to prevent membrane fouling. Due to an early warning from the real-time monitoring, the coming membrane-fouling is predictable and the operating conditions, such as backflow ratio, can be changed to minimize the biofouling rate.

The evaluation of eco-toxicity of ionic liquids (ILs) in the aquatic environment is essential for their safe utilization and QSTR approach plays an important role in obtaining the eco-toxicity data of ILs with diverse structures. Usually, the descriptors used to build QSTR model were made up of anion and cation descriptors, and their interactions were often neglected to some extent. In this work, based on the optimization of the ILs structure, a new set of descriptors were proposed to describe the interaction between anions and cations, and some new atomic distribution matrices were constructed to calculate norm descriptors of ILs, anion and cation. A norm index-based QSTR model was built to predict the eco-toxicity of ILs toward Leukemia rat cell line (IPC-81). This model has satisfactory statistical results with the R2 of 0.954 and RMSE of 0.241, respectively. Furthermore, leave-one-out cross-validation and applicability domain results showed good stability and predictability of this model. This approach showed that the interaction between cations and anions could be reflected by optimizing the whole structure of ILs which might play an important role for describing the eco-toxicity of ILs. Therefore, it is further suggested that the norm descriptors would be applicable to predict the eco-toxicity of ILs towards IPC-81.