Insight into the role of reactive species on catalyst surface underlying peroxymonosulfate activation by P-Fe2MnO4 loaded on bentonite for trichloroethylene degradation.

In this study, bentonite supporting phosphorus-doped Fe2MnO4 (BPF) was synthesized and applied for PMS activation to degrade TCE. Morphology and structure characterization results indicated the successfully synthesized of BPF, and the BPF/PMS system not only featured high TCE removal (97.4%) but also high reaction rate constant (kobs = 0.0554 min-1) and PMS utilization (70.4%, kobs = 0.0228 min-1). According to the results of various experiments, massive oxygen vacancies on P-Fe2MnO4 alter its charge balance and facilitate the electron transfer process named adjacent transfer (direct electron capture by adsorbed PMS from adjacent TCE). Mn(III) is the main adsorption site for PMS, and the hydroxyl groups on the catalyst (Fe sites of P-Fe2MnO4, Si and Al sites of bentonite) can also offer binding sites for PMS. The hydrogen-bonded PMS on Fe(III) and Mn(III) sites will subsequently accept the discharged electrons to generate free radicals and high-valent metal species. Meanwhile, electron loss of HSO5- that chemically bonded to hydroxyl groups on bentonite will generate SO5•-, which will further produce 1O2 through self-bonding. the active species on the catalyst surface contribute 65% of TCE degradation in the heterogeneous catalytic oxidation system.

Retention and transport of PFOA and its fluorinated substitute, GenX, through water-saturated soil columns.

Perfluoro-2-propoxypropanoic acid (GenX) has emerged as a substitute for perfluorooctanoic acid (PFOA) especially since PFOA was listed among the persistent organic pollutants (POPs) by the Stockholm Convention in 2019. However, limited knowledge exists regarding the behavior and mobility of GenX in natural soils hindering the prediction of its environmental fate. This study investigated the mobility and retention of GenX and PFOA in soils under batch and water-saturated flow-through conditions. Batch experiments revealed that GenX has a lower binding affinity to soil than longer-chained PFOA, potentially threatening groundwater resources. Unlike metal-oxides/minerals (ferrihydrite, gibbsite and manganese dioxide), biochar (BC) and activated carbon (AC) amendments significantly enhanced the sorption of both GenX and PFOA in soil. Sorption data on minerals and carbonaceous materials implied that for shorter-chained GenX, the predominant mode of sorption was through electrostatic (ionic) interactions, while for longer-chained PFOA, hydrophobic interactions became progressively more important with increasing chain length. The dynamic flow experiments demonstrated that these soil amendments enhanced the retention of both compounds, thereby decreasing their mobility. Simultaneous injection of both compounds into columns pre-loaded with either PFOA or GenX increased their retardation. GenX sorption was more affected by pre-sorbed PFOA compared to the minimal impact of pre-loaded GenX on PFOA sorption. A newly developed reactive transport model, which incorporates a two-site sorption model and accounts for kinetic-limited processes, accurately predicted the sorption and transport of both compounds in single and binary contamination systems. These findings have important implications for predicting and assessing the fate and mobility of per- and polyfluoroalkyl substances (PFAS) in soils and groundwaters.

Continuous and discontinuous multi-generational disturbances of tetrabromobisphenol A on longevity in Caenorhabditis elegans.

Tetrabromobisphenol A (TBBPA) is one of the most prevalently used brominated flame retardants. Due to its persistence, it is predominantly found in environmental matrices and has the potential to generate multi-generational toxicity. However, knowledge of its adaptive response or long-term residual effect in multi-generations, and molecular mechanisms remain understudied. In the current study, the model animal nematode Caenorhabditis elegans (C. elegans) was exposed to TBBPA at environmentally realistic concentrations (0.1-1000 µg L-1) for four consecutive generations (G0 to G3). Degenerative age-related multiple endpoints including lifespan, locomotion behaviors, growth, reproduction, oxidative stress-related biochemical responses, cell apoptosis, and stress related gene expressions were assessed in the continuous exposure generations (G0 and G3) and the discontinuously exposed generations (T3 and T'3). The results showed that changes in degenerative age-related response monitored four generations varied in direction and magnitude depending on the TBBPA concentrations, and the response intensify ranked as G0 > T'3/G3 > T3. TBBPA at 1 µg L-1 dosage was detected as the lowest observed effect concentration in multi-biomarkers. The underlying mechanism of aging phenotypes was that reactive oxygen species accumulation led to cell apoptosis regulated by gene ape-1, and confirmed catalase enzyme and superoxide dismutase activity played a crucial role in the detoxification process of TBBPA at the molecular level. This study provided insights into the underlying mechanism of TBBPA-interfered longevity and its environmental multi-generational potential risks.

Heavy metals in daily meals and food ingredients in the Yangtze River Delta and their probabilistic health risk assessment.

Heavy metal exposure via food consumption is inadequately investigated and deserves considerable attention. We collected hundreds of food ingredients and daily meals and assessed their probabilistic health risk using a Monte Carlo simulation based on an ingestion rate investigation. The detected concentrations of four heavy metals (Cr, Cd, Pb, and Hg) in all daily meal samples were within the limits stipulated in the National Food Safety Standard (GB 2762-2017), while that for As level was excessive in 0.3 % of daily meal samples. The same results were also observed in most food ingredient samples, and a standard-exceeding ratio of 23 % of As was observed in aquatic food or products, especially seafood, which was with the highest concentration reaching 1.24 mg/kg. Combining the detected heavy metal amounts with the ingestion rate investigation, the hazard quotients (HQs) of As, Cr, Cd, Pb, and Hg in daily meals and food ingredients were all calculated as lower than 1 (no obvious harm), while the incremental lifetime cancer risk (ILCR) of As and Cr (>1 × 10-4), indicating that the residual As posed potential health effects to human health. It was noteworthy that the proportion of aquatic foods only accounted for 6.3 % of daily meals, but they occupied 41.1 % of the heavy metal exposure, which could be attributed to the high amounts of heavy metals in aquatic foods. This study not only provided basic data of heavy metal exposure and potential health risks through daily oral dietary intake, but also illuminated the contribution of different kinds of food ingredients. Specifically, the study highlighted the contamination of aquatic foods with As, especially seafood such as shellfish and bivalves.

Using EEM-PARAFAC to identify and trace the pollution sources of surface water with receptor models in Taihu Lake Basin, China.

The identification and apportionment of the multiple pollution sources are essential and crucial for improving the effectiveness of surface water resources management. In this study, the surface water samples were collected from Taihu Lake Basin, and the optimal water quality parameters for the receptor models were selected firstly with multivariate statistical analyses. In order to identify the potential pollution sources in surface water, dissolved organic matter (DOM) was analyzed with the excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC). Through the Pearson correlation analysis of water quality parameters and DOM components, the pollution sources were further verified, i.e., agricultural activities, domestic sewage, phytoplankton growth/terrestrial input and industrial sources. In addition, principal component analysis (PCA) combined with the absolute principal component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) models were employed to quantify pollution sources. Compared with PCA-APCS-MLR model, PMF model resulted in higher performance on evaluation statistics and lower proportion of unexplained variability, thus showed more realistic and robust representation. The results of PMF showed that agricultural activities (42.08%) and domestic sewage (21.16%) were identified as the dominant pollution sources of surface water in the study area. This study highlights the effectiveness of EEM-PARAFAC in identifying the pollution sources, and the applicability of PMF in apportioning the contributions of each potential pollution source in surface water.

Inactivation and photoreactivation of blaNDM-1-carrying super-resistant bacteria by UV, chlorination and UV/chlorination.

The excessive dissemination of New Delhi metallo-ß-lactamase-1 (NDM-1), which mediates resistance to a majority of clinical ß-lactam antibiotics, has created a major public health problem worldwide. Herein, a blaNDM-1-carrying (plasmid encoded) super-resistant bacterium, Acinetobacter sp. CS-2, was selected to reveal its mechanisms of inactivation and photoreactivation during UV, chlorination and UV/chlorination disinfection. The inactivated CS-2 underwent a certain photoreactivation after UV and chlorination. The logistic model precisely fitted the data obtained in the photoreactivation experiments by UV treatment, with the estimated kinetic parameters Sm (0.530%-12.071%) and k2 (0.0009-0.0471). The photoreactivation of Acinetobacter sp. CS-2 was observed when treated by chlorination at a dosage of 0.5 mg/L with a survival ratio of 34.04%. UV/chlorination not only resulted in the high-efficiency reduction of CS-2 but also effectively controlled its photoreactivation with a survival ratio of 0%- 0.87%. UV/chlorination showed great advantages in causing the irreversible destruction of bacterial surface structures by making the cell membranes wrinkled and incomplete compared with UV disinfection. The singlet oxygen (1O2) generated during UV/chlorination treatment played a vital role in blaNDM-1 removal. This study proposed new insights into the mechanism of inactivation and the characteristics of photoreactivation for the super-resistant bacteria by UV, chlorination and UV/chlorination.

Brominated flame retardants (BFRs) in sediment from a typical e-waste dismantling region in Southern China: Occurrence, spatial distribution, composition profiles, and ecological risks.

Our study evaluated the current occurrence, composition, and spatial distribution of eight congeners of polybrominated diphenyl ethers (PBDEs) and seven novel brominated flame retardants (NBFRs) in sediment from Guiyu, a typical e-waste dismantling region in China. PBDEs levels ranged from 0.345 to 401,000 ng/g dw and NBFRs levels ranged from 0.581 to 73,100 ng/g dw. Almost all sediment samples contained high levels of BDE-209 and DBDPE, and the ratio of DBDPE/BDE-209 in sediments ranged from 0.0814 to 2.80 (mean: 0.879). The concentration and composition profiles for BFRs in sediments from both mainstream and tributaries of two major rivers in Guiyu reach (and adjacent downstream locations) differed significantly from those far from Guiyu town. Whereas the high presence of BFRs in Guiyu reflected the historical crude e-waste dismantling activities in the region; the locations far from Guiyu town were likely to receive BFRs from atmospheric deposition, not originated from the region, as BFRs in water-sediment are known to be able to migrate a limited distance along the river. Ecological risk assessment revealed that the low brominated congeners of PBDEs and BDE-209 posed an unacceptable risk to the sedimentary life at multiple locations. Our results updated our knowledge of BFRs contamination in Guiyu, suggesting the necessity of continuous source monitoring, control procedures, and sediment cleanup for BFRs.

Antibiotic residue and toxicity assessment of wastewater during the pharmaceutical production processes.

Various pollutants are released during pharmaceutical production processes, which is of great concern. Most studies have focused on the terminal treatment results of mixed pharmaceutical wastewater, and further research on wastewater from the production processes is required. This study investigated the wastewater quality indicators, residual antibiotics, and biological toxicity of the wastewater during the production process in a large pharmaceutical producing factory in Northern China. The wastewater contained numerous organic pollutants, with the chemical oxygen demand (COD) values ranging from 2.0 × 103 to 2.6 × 105 mg L-1 and the total nitrogen (TN) values ranging from 1.3 × 103 to 2.0 × 104 mg L-1. High concentrations of cephalexin and cefradine remained in the wastewater of the production workshop, with the highest concentration of cefradine reaching 1328 mg L-1. The wastewater from the oxidation and solvent recovery workshops was more toxic to Vibrio fischeri and Daphnia magna than that of other workshops. Moreover, the biological acute toxicity of wastewater was significantly correlated with the concentration of COD and TN (p < 0.01). This study provides new insights into the treatment of antibiotic production wastewater, illuminating the incomplete extraction of products and the significant risk posed by pharmaceutical wastewater to the environment.

Chelating surfactant N-lauroyl ethylenediamine triacetate enhanced electrokinetic remediation of copper and decabromodiphenyl ether co-contaminated low permeability soil: Applicability analysis.

In this study, chelating surfactant N-lauroyl ethylenediamine triacetate (N-LED3A) was used as strengthening agent for electrokinetic (EK) remediation of copper (Cu) and decabromodiphenyl ether (BDE209) co-contaminated low permeability soil. The results indicated that negligible amount of N-LED3A would be adsorbed on the experimental soil. The synchronous elution efficiencies (SEEs) of Cu and BDE209 had reached 65.4% and 49.9%, respectively, when the concentration of N-LED3A was 4000 mg/L, and they kept almost unchanged as the concentration of N-LED3A further increased. Meanwhile, the optimal SEEs were obtained at the pH condition within 6-8. The removal efficiencies of Cu (55.3%-65.8%) and BDE209 (31.4%-46.4%) would be increased with the applied voltage gradient and concentration of N-LED3A. In addition, BDE209 and Cu contaminants were also detected in the catholyte and anolyte, respectively, and their concentrations still showed an uptrend by the end of the experiments. While in the control experiments, the removal efficiency of Cu was in the range of 18.2%-23.6%, and almost no BDE209 was migrated out. The electric current would be increased with N-LED3A concentration increased, further resulting in the enhancement of cumulative electro-osmotic flow (EOF). However, the increment of EOF was limited after an 8-day treatment due to the declined capacity of the soil water supply, and the removal efficiency of BDE209 did not change proportionally to the cumulative EOF as a consequence. The accumulated (21 days) energy consumption under the optimal operation conditions (voltage gradient 1 V/cm, N-LED3A 1 g/L) was 377.28 KWh/m3. Efficiently synchronous removal of BDE209 and Cu could be achieved by the N-LED3A enhanced EK technique, exhibiting a promising application potential in the organic pollutant and heavy metal co-contaminated soil remediation.

Pseudo toxicity abatement effect of norfloxacin and copper combined exposure on Caenorhabditis elegans.

The coexistence of antibiotics and heavy metals may result in complex ecotoxicological effects on living organisms. In this work, the combined toxic effects of norfloxacin (NOR) and copper (Cu) on Caenorhabditis elegans (C. elegans) were investigated due to the highly possible co-pollution tendency. The results indicated that locomotion behaviors (frequency of head thrash and body bend) of C. elegans were more sensitive as the exposure time of NOR or Cu prolonged. Meanwhile, the physiological indexes (locomotion behaviors, body length) of C. elegans were more sensitive to the combined pollution that with lower Cu dosage (0.0125 µM), in prolonged exposure experiments. In addition, the toxic effects of NOR-Cu on physiological indexes of C. elegans seemed to be alleviated during prolonged exposure when Cu was 1.25 µM. Similarly, the ROS production and apoptosis level almost unchanged with the addition of NOR compared with Cu (1.25 µM) exposure groups, but both significantly higher than the control groups. Furthermore, compared with Cu (0.0125 µM and 1.25 µM) exposure experiments, the addition of NOR had resulted in the genetic expression decrease of hsp-16.1, hsp-16.2, hsp-16.48, and the oxidative stress in C. elegans seems to be alleviated. However, the significantly decreased of ape-1 and sod-3 expression indicated the disruption of ROS defense mechanism. The irregular change in ace-1 and ace-2 gene expressions in NOR-Cu (0.0125 µM) would result in the locomotion behaviors disorders of C. elegans, and this also explains why C. elegans are more sensitive to the combination of NOR and lower concentration of Cu.

Bioaccumulation, elimination and metabolism in earthworms and microbial indices responses after exposure to decabromodiphenyl ethane in a soil-earthworm-microbe system.

As a novel brominated flame retardant (NBFR), decabromodiphenyl ethane (DBDPE) has been poorly understood for the environmental fate and toxicity in terrestrial invertebrates. For the first time, the bioaccumulation, elimination, metabolism and detoxification of DBDPE in earthworms as well as its potential impacts on soil microbes were investigated. The results showed much higher DBDPE concentrations in casts than in earthworms. The bioaccumulation factor (BAF) and elimination rate constant (ke) values were 0.028-0.213 (gdw, worm/gdw, soil) and 0.323-0.452 (day-1), respectively. The detoxifying enzymes (CYP450 and GST) could be induced by DBDPE within the range of exposure dosage, and the activities were significantly increased at 21 d (p < 0.05). The results were identified by GC-ECNI-MS, and it showed that at least eleven unknown peaks were separately observed in the earthworms, which were the biotransformation products of DBDPE in earthworms. Additionally, the damages, including skin shrinkage, setae impairment, and intercellular vacuolization, were clearly observed by SEM/TEM. Based on these data, DBDPE could accumulate in earthworms, yet, with low bioaccumulation ability. Moreover, DBDPE exposure resulted in minimal harmful impacts on microbial activities including microbial biomass C (MBC), Microbial basal respiration (MBR), Urease (US) activity and fluorescein diacetate hydrolase (FDA) activity (p < 0.05). Our findings would provide some essential information for interpreting the ecological risks of DBDPE in soil.

Risk assessment of antibiotic resistance genes in the drinking water system.

Antibiotic resistance genes (ARGs) are extensively detected in various environmental media, whose risk assessment in the drinking water systems has not been comprehensive. This study established a new risk assessment of ARGs in the drinking water systems, considering the chlorine-resistance ability, transferability, and ARGs harboring potential of pathogens. The risk of ARGs in a typical drinking water reservoir was also evaluated based on the detection of ARGs and antibiotic-resistant bacteria (ARB). Fourteen ARGs were detected with a relative concentration range of 10-4-10-3 (ARGs/16S rRNA gene). Five isolated ARB were identified as human opportunistic pathogens, one of which (Pseudomonas aeruginosa HLS-6, CCTCC AB 2017269) is resistant to hundreds of milligrams per liter levels of antibiotics and low-level chlorine. This result indicated that ARB tolerant to high-levels of antibiotics could be isolated from environments containing trace levels of antibiotics. Moreover, complete genome sequencing confirmed the inclusion of ARGs (sul1, aadA2) on the class I integron in HLS-6, indicating that the risk of ARGs in this drinking water reservoir could be classified as resistance risk ranking in drinking water system 1 (R3DW 1). The risk assessment of ARGs in this study provides a clear understanding of ARG risk in drinking water systems. The results reveal that the ARGs and ARB contamination of drinking water reservoirs pose significant challenges for drinking water treatment efficiency and affect drinking water safety.

Comprehensive adsorption behavior and mechanism of PFOA and PFCs in various subsurface systems in China.

The adsorption-desorption performance of perfluorooctanoic acid (PFOA), one of the environmentally persistent pollutants which is refractory to degrade in soil, was investigated and reported. The adsorption-desorption process of PFOA was firstly conducted using different fractions (sand, coarse silt and fine silt) of soil collected from Shanghai, China. More than 50% of PFOA (2.0 mg/L) could be adsorbed by soils while only less than 10% of which could be desorbed once contamination occurs. The kinetics and particle diffusion rates of PFOA in different fractions of soil were calculated and analyzed in detail. Apart from this, the retention of short-chained PFCs, which can be generated as degradation products of PFOA, were also measured. In single solute systems, the adsorption of pollutants in soils dramatically increased as the chain length of PFCs grew longer. Similarly, in mixed solutions, preferential adsorption of longer-chained PFCs over shorter chains in soils were sited, attributable to the stronger hydrophobicity of the pollutants. However, the desorption of them performed in reverse, where the desorption rates of longer-chained PFCs were far lower than those of shorter ones. Furthermore, influencing factors including pH, temperature and co-existing matters were studied during the adsorption process. After comprehending the adsorption behavior of PFOA in soil fractions, the situation of the adsorption of PFOA in various soils chosen from nine provinces in China was investigated and compared. There was an obvious discrepancy, whether it be from the rate or the amount of adsorption of PFOA (approximately 10%), in the nine different soils. Finally, a multiple linear regressive equation was employed to sort influencing parameters which are prone to affect the adsorption of PFOA in soils, the contribution of these are provided in order of relevance. These results demonstrate the adsorption performance and behavior of PFOA and PFCs in different soils, which can be utilized as a scientific reference for maximizing remediation of PFOA polluted sites in the future.

Characteristics of legacy and novel brominated flame retardants in water and sediment surrounding two e-waste dismantling regions in Taizhou, eastern China.

A total of 51 water and 43 sediment samples were collected from the locations surrounding the two e-waste dismantling zones in Taizhou, the Fengjiang resource recycling industrial zone (FJ, shut down in 2017) and the Taizhou resource recycling base (TZ, newly constructed in recent years). The concentrations of polybrominated diphenyl ethers (PBDEs) ranged from 1.7 to 44 ng/L in water and from not detected (nd) to 7100 ng/g in sediment. Novel brominated flame retardants (NBFRs) ranged from 0.29 to 1.6 ng/L in water, and from nd to 5300 ng/g in sediment. The levels of PBDEs and NBFRs in the water were comparable between FJ and TZ, while their concentrations were higher in the sediment from FJ than those from TZ. The levels of BDE-28, BDE-153, pentabromotoluene (PBT), pentabromobenzene (PBB), ∑PBDEs and ∑BFRs in the water from FJ or TZ were found to be significantly negatively associated with the distance from the zone center. However, in the sediments from FJ and TZ, the BFRs levels did not decrease from the center to the outer regions. BDE-209 and decabromodiphenyl ethane (DBDPE) were predominant in the sediments and the ratio of DBDPE/BDE-209 were as high as 5.6 (mean: 0.97). The mass burden of PBDEs, BDE-209, DBDPE, 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and HBB in the riverine sediments in Luqiao District was 829, 787, 363, 85, and 61 kg, respectively. The ecological risk assessment revealed that BDE-99 posed an unacceptable risk to aquatic life at 86% of the locations. The hazard quotients for penta-BDE, BDE-209, and HBB exceeded one for 30%, 28%, and 2.3% of the sediment samples, respectively.

Exploring different mechanisms of biochars in removing hexavalent chromium: Sorption, reduction and electron shuttle.

The role of different biochars in Cr(VI) removal process is not clear. Two raw materials with distinct components were prepared into biochars at various pyrolysis temperatures. The biochar derived from cotton stark (with less lignin than walnut shell) always had more surface functional groups. The pyrolysis temperature had a significant effect on the biochar. In the sorption experiments, the fitting results of two compartment models showed that slow compartment dominated by surface functional groups plays a leading role in the Cr(VI) removal by low-temperature char, while the contribution of the rapid or slow compartment to the process of high-temperature char was equal. In the experiment of biochar mediated the lactate to reduce Cr(VI), the biochar derived from walnut shell (richer lignin) had better conductivity due to its highly aromatic structure, which could directly transfer electrons. This study indicated that various biochars may play different roles in the Cr(VI) removal process.

Annual trends and health risks of antibiotics and antibiotic resistance genes in a drinking water source in East China.

The extensive pollution of antibiotics and antibiotic resistance genes (ARGs) in drinking water has aroused worldwide concern. Successive monitoring of these pollutants has noteworthy significance for drinking water safety. Accordingly, this study conducted successive monitoring of antibiotics and ARGs from 2015 to 2017 in a drinking water source in East China. The total antibiotic concentration ranged from 19.68 ng/L to 497.00 ng/L, and decreased slightly from 2015 to 2017. Eighteen out of forty-one ARG subtypes showing resistance to six antibiotic classes and one class I integrase gene intI1, were detected in the drinking water source at concentrations ranging from 6.5 × 104 copies/mL to 1.6 × 106 copies/mL. Importantly, the total ARG concentration increased on an annual basis from 2015 to 2017 with an average annual increment of 0.25 orders of magnitude, which was mainly attributed to the increase in specific ARG subtypes, such as sul1, sul2, sul3, tetA, qnrB, and ermB. Most ARGs was positively correlated with the intI1 genes (r = 0.47-0.55, P < 0.01). Furthermore, the variation of antibiotics and ARGs appeared to be related to the water indices, particularly of the values of COD, BOD5, NO2-N (P < 0.05). This study provides basic data on antibiotic and ARG pollution in the studied drinking water source. Importantly, the findings expound that although the residual antibiotics in this drinking water source decreased slightly from 2015 to 2017, while its biological effect, the antibiotic resistance, increased annually, which give a warning of the antibiotic resistance pollution in the drinking water source.

Occurrence and removal of antibiotics, antibiotic resistance genes, and bacterial communities in hospital wastewater.

Hospital wastewater contains a variety of human antibiotics and pathogens, which makes the treatment of hospital wastewater essential. However, there is a lack of research on these pollutants at hospital wastewater treatment plants. In this study, the characteristics and removal of antibiotics and antibiotic resistance genes (ARGs) in the independent treatment processes of hospitals of different scales (primary hospital, H1; secondary hospital, H2; and tertiary hospital, H3) were investigated. The occurrence of antibiotics and ARGs in wastewater from three hospitals varied greatly. The first-generation cephalosporin cefradine was detected at a concentration of 2.38 µg/L in untreated wastewater from H1, while the fourth-generation cephalosporin cefepime had the highest concentration, 540.39 µg/L, at H3. Ofloxacin was detected at a frequency of 100% and had removal efficiencies of 44.2%, 51.5%, and 81.6% at H1, H2, and H3, respectively. The highest relative abundances of the ß-lactam resistance gene blaGES-1 (1.77×10-3 copies/16S rRNA), the quinolone resistance gene qnrA (8.81×10-6 copies/16S rRNA), and the integron intI1 (1.86×10-4 copies/16S rRNA) were detected in the treated wastewater. The concentrations of several ARGs were increased in the treated wastewater (e.g. blaOXA-1, blaOXA-10, and blaTEM-1). Several pathogenic or opportunistic bacteria (e.g. Acinetobacter, Klebsiella, Aeromonas, and Pseudomonas) were observed at high relative abundances in the treated wastewater. These results suggested the co-occurrence of antibiotics, ARGs, and antibiotic-resistant pathogens in hospital wastewater, and these factors may spread into the receiving aquatic environment.

Occurrence of heavy metals, antibiotics, and antibiotic resistance genes in different kinds of land-applied manure in China.

Various pollutants remaining in the livestock and poultry manures pose potential threat to the soil ecosystem during land application, whose impact should be appreciated. The occurrence of heavy metals, antibiotics, and antibiotic resistance genes (ARGs) in swine manure (SM), chicken manure (CM), and the SM organic fertilizer (OF) were investigated. The order of total concentrations of antibiotics detected in manures was as follows: SM > CM > OF. The amount of ciprofloxacin (CIP) in SM reached up to 6.61 mg/kg, which only occupied 1% of the antibiotic concentration reported in the past years. The total concentration of thirteen ARGs in CM ranked first, reaching 7.35 × 1011 copies/g, among which the strB gene was detected with the highest concentration. It was worth noting that the qnr ARGs were persistent in OF with the absence of corresponding antibiotics, indicating ARGs were harder to remove than antibiotics during manure composting. Zn and Cu (46.5-843 mg/kg) were obviously higher than other seven heavy metals, and significantly correlated with most ARGs (p < 0.01). This study provided the basic data of the pollution in animal manures that will be land-applied, illuminating the original source of potential risk in soil ecosystem.

Direct and efficient reduction of perfluorooctanoic acid using bimetallic catalyst supported on carbon.

A variety of metal elements have exhibited strong reductive and dehalogenative capabilities for the removal of persistent organic pollutants, owing to electron transfer or electron-hole activation through various methods. Herein, a bimetallic CNi-Al2O3 structure (AlCNi) was successfully synthesized to simultaneously function as sorbent and catalyst in the reduction of perfluoroalkyl carboxylic acids (PFOA) polluted wastewater. Using a reaction period of 3 h, 98% of PFOA was removed by AlCNi through a mechanochemical stirring method and 70.43% of fluorine ions was released from PFOA anchored onto the surface of AlCNi. Both thermocatalysis and photocatalysis technologies were incorporated and compared when utilized in tandem with AlCNi to mitigate the PFOA. In addition, peroxymonosulfate (PMS) and sodium sulfite (Na2SO3) were also integrated into experiments, separately, as a strong oxidant and reductant to improve the degradation effect of PFOA. However, the degradation efficiency of both were lower than that of AlCNi, even when assisted by elevated temperatures and ultraviolet irradiation. The feasibility of employing AlCNi for PFOA degradation was further investigated at various temperature and pH conditions. The data obtained from HPLC-MS/MS, TOC, and IC with multiple characterizations of AlCNi/PFOA, proposed the predominant degradation pathways comprising adsorption, defluorination-hydroxylation, and decarboxylation. This study provides a valuable remediation method without utilizing chemical agents and special activation for PFOA by AlCNi, which can be suitable for large-scale sewage treatment applications.

Insights from comparative proteomic analysis into degradation of phenanthrene and salt tolerance by the halophilic Martelella strain AD-3.

A halophilic PAHs-degrading strain, Martelella AD-3, was previously isolated from highly saline petroleum-contaminated soil. In this study, label-free proteomics were performed to identify differentially expressed proteins (DEPs) under Group P (phenanthrene +5% salinity) and Group G (glycerol +1% salinity), which would help to reveal the mechanism of phenanthrene degradation and salt tolerance. A total of 307 up-regulated DEPs were found in Group P, including 17 phenanthrene degradation proteins. Among these phenanthrene-degrading proteins, the ferredoxin of aromatic ring-hydroxylating dioxygenase (RHD) was up-regulated by 110-fold and gentisate 1,2-dioxygenases (GDOs) were only expressed in Group P. Besides, we also found nine high salt stress response proteins, including ectoine synthase and transport protein of compatible (osmoprotectant) solutes, were differentially up-regulated. These results indicate that strain AD-3 mainly relied on RHD and dihydrodiol dehydrogenase to degrade phenanthrene, and accumulated compatible solutes for resistance to salt stress. This study provides strong theoretical guidance for understanding the degradation of phenanthrene by strain AD-3 in high salt environments.