Deciphering the core bacterial community structure and function and their response to environmental factors in activated sludge from pharmaceutical wastewater treatment plants.

Pharmaceutical wastewater is recognized for its heightened concentrations of organic pollutants, and biological treatment stands out as an effective technology to remove these organic pollution. Therefore, a comprehensive exploration of core bacterial community compositions, functions, and their responses to environmental factors in pharmaceutical wastewater treatment plants (PWWTPs) is important for understanding the removal mechanism of these organic pollutants. This study comprehensively investigated 36 activated sludge (AS) samples from 15 PWWTPs in China. The results revealed that Proteobacteria (45.41%) was the dominant phylum in AS samples, followed by Bacteroidetes (19.54%) and Chloroflexi (4.13%). While the dominant genera were similar in both aerobic and anaerobic treatment processes, their relative abundances exhibited significant variations. Genera like HA73, Kosmotoga, and Desulfovibrio were more abundant during anaerobic treatment, while Rhodoplanes, Bdellovibrio, and Hyphomicrobium dominated during aerobic treatment. 13 and 10 core operational taxonomic units (OTUs) were identified in aerobic and anaerobic sludge, respectively. Further analysis revealed that core OTUs belonging to genera Kosmotoga, Desulfovibrio, Thauera, Hyphomicrobium, and Chelativorans, were associated with key functions, including sulfur metabolism, methane metabolism, amino acid metabolism, carbohydrate metabolism, toluene degradation, and nitrogen metabolism. Furthermore, this study highlighted the crucial roles of environmental factors, such as COD, NH4+-N, SO42-, and TP, in shaping both the structure and core functions of bacterial communities within AS of PWWTPs. Notably, these factors indirectly affect functional attributes by modulating the bacterial community composition and structure in pharmaceutical wastewater. These findings provide valuable insights for optimizing the efficiency of biochemical treatment processes in PWWTPs.

Prevalence of antibiotics, antibiotic resistance genes, and their associations in municipal wastewater treatment plants along the Yangtze River basin, China.

The overuse and misuse of antibiotics have resulted in the pollution of antibiotics and antibiotic resistance genes (ARGs) in municipal wastewater treatment plants (WWTPs), posing threats to ecological security and human health. Thus, a comprehensive investigation was conducted to assess the occurrence, removal efficiency, and ecological risk of antibiotics, along with the diversity, abundance, and co-occurrence of ARGs, and their correlations in 13 WWTPs along the Yangtze River Basin. Among 35 target antibiotics, 23 antibiotics within 6 categories were detected in all the samples. Amoxicillin (AMO), ofloxacin (OFL), and pefloxacin (PEF) were predominant in influents, while AMO exhibited dominance with the highest concentration of 1409 ng/L in effluents. Although antibiotic removal performance varied among different WWTPs, a significant decrease in each antibiotic category and overall antibiotics was observed in effluents compared with that in influents (p < 0.05). Remarkably, ecological risk assessment revealed high risks associated with AMO and ciprofloxacin (CIP) and medium risks linked to several antibiotics, notably including OFL, roxithromycin (ROX), clarithromycin (CLA), and tetracycline (TC). Furthermore, 96 ARG subtypes within 12 resistance types were detected in this study, and the total absolute abundance and diversity of ARGs were significantly decreased from influents to effluents (p < 0.05). Enrichment of 38 ARGs (e.g., blaNDM, ermA, vatA, mexA, and dfrA25) in effluents indicated potential health risks. Various mobile genetic elements (MGEs), exhibited significant correlations with a majority of ARGs in both influents and effluents, such as intⅠ1, tnpA1, tnpA5, and tp614, underscoring the important role of MGEs in contributing to the ARG dissemination. Many antibiotics displayed lower correlations with corresponding ARGs, but exhibited higher correlations with other ARGs, suggesting complex selective pressures influencing ARG propagation. Overall, the incomplete elimination of antibiotics and ARGs in WWTPs is likely to pose adverse impacts on aquatic ecosystems in the Yangtze River Basin.

Romantic relationships attenuated competition between lovers: evidence from brain synchronization.

Competition is an essential component of social interaction and is influenced by interpersonal relationships. This study is based on social exchange theory and explores the relationship between brain synchronization and competition in the binary system of romantic relationships through electroencephalogram hyperscanning technology. The results found that females had a greater win rate in the romantic and friend groups. During the early stage (0-200 ms), when the competitive target appeared, the stranger group exhibited greater interbrain synchronicity in the Alpha frequency band. However, during the later stage (600-800 ms), the romantic group showed higher Alpha band interbrain synchrony when the competitive target appeared. Significant interbrain synchronizations were observed in the Theta frequency band of the stranger and friend groups at 400-600 ms and 800-1000 ms. Moreover, these interbrain synchronizations were significantly positively correlated with the winning rates of females in the competition. These findings suggest a close relationship between interpersonal coordination and interbrain synchronization. Furthermore, romantic relationships reduce participants' willingness to compete, affecting their attention regulation, emotional processing, and goal orientation, thus influencing competition. This study investigated the impact of romantic relationships on competition, providing a theoretical foundation for promoting the positive and healthy development of romantic relationships.

The shorter a man is, the more he defends fairness: relative height disadvantage promoting third-party punishment-evidence from inter-brain synchronization.

Third-party punishment occurs in interpersonal interactions to sustain social norms, and is strongly influenced by the characteristics of the interacting individuals. During social interactions, height is the striking physical appearance features first observed, height disadvantage may critically influence men's behavior and mental health. Herein, we explored the influence of height disadvantage on third-party punishment through time-frequency analysis and electroencephalography hyperscanning. Two participants were randomly designated as the recipient and third party after height comparison and instructed to complete third-party punishment task. Compared with when the third party's height is higher than the recipient's height, when the third party's height is lower, the punishment rate and transfer amount were significantly higher. Only for highly unfair offers, the theta power was significantly greater when the third party's height was lower. The inter-brain synchronization between the recipient and the third party was significantly stronger when the third party's height was lower. Compared with the fair and medium unfair offers, the inter-brain synchronization was strongest for highly unfair offers. Our findings indicate that the height disadvantage-induced anger and reputation concern promote third-party punishment and inter-brain synchronization. This study enriches research perspective and expands the application of the theory of Napoleon complex.

The absence of one's intimate partner promotes dyadic competition through enhanced interbrain synchronization between opponents.

Competition is a common occurrence in life, but the influence of intimate relationships on people's competitiveness remains unknown. Grounded in Darwin's theory of sexual selection, this study utilized EEG hyperscanning technology to investigate the influence of the presence of romantic partners and the gender of competitors on the interbrain synchronization of female individuals during competitive contexts. The research results showed that in competitive interactions, there was a significant increase in Theta and Alpha frequency band activity between females and their competitors. Interbrain synchronization was strongest when their partners were not nearby and females competed with same gender competitors. The research results indicate that intimate companionship has an impact on the early alertness and late cognitive execution mechanisms of female individuals in competition, and due to intimate relationships, females pay more attention to same-gender competitors. This study demonstrates that the presence of intimate partners can affect a female's competitive state and brain synchronization with opponents of different genders, improving the theoretical explanation of intimate relationships and competitive interactions.

Deciphering the dynamics and driving mechanisms of high-risk antibiotic resistome in size-fractionated bacterial community during drinking water chlorination via metagenomic analysis.

To reveal the impact of chlorination on the high-risk resistome in size-fractionated bacterial community, we employed metagenomic approaches to decipher dynamics of high-risk antibiotic resistance genes (ARGs) and driving mechanisms in the free-living and particle-associated fractions within a full-scale drinking water treatment system. Our results revealed that chlorination significantly increased the relative abundance of high-risk ARGs in the free-living fraction to 0.33 ± 0.005 copies/cell (cpc), bacitracin and chloramphenicol resistance types were major contributors. Furthermore, chlorination significantly increased the relative abundance of mobile genetic elements (MGEs) in the free-living fraction, while decreasing it in the particle-associated fraction. During chlorination, size-fractionated bacterial communities varied considerably. Multiple statistical analyses highlighted the pivotal role of the bacterial community in altering high-risk ARGs in both the free-living and particle-associated fractions, while MGEs had a more pronounced impact on high-risk ARGs in the free-living fraction. Specifically, the enrichment of pathogenic hosts, such as Comamonas and Pseudomonas, led to an increase in the abundance of high-risk ARGs. Concurrently, MGEs exhibited significant correlations with high-risk ARGs, indicating the potential of horizontal transfer of high-risk ARGs. These findings provide novel insights for mitigating antibiotic resistance risk by considering different bacterial fractions and respective risk ranks in drinking water.

Free-living lifestyle preferences drive the antibiotic resistance promotion during drinking water chlorination.

The risk associated with antibiotic resistance genes (ARGs) in size-fractionated bacterial community during drinking water chlorination remains unclear, and is of paramount importance for risk mitigation through process selection and optimization. This study employed metagenomic approaches to reveal the alterations of ARGs, their potential functions and hosts within the free-living and particle-associated fractions. The total relative abundance of ARGs, mobile genetic elements (MGEs), and virulence factor genes (VFGs) significantly increased in the free-living fraction after chlorination. The contribution of the free-living fraction to the ARG relative abundance rose from 16.40 ± 1.31 % to 93.62 ± 0.47 % after chlorination. Multidrug resistance genes (e.g. mexF and mexW) were major contributors, and their co-occurrence with MGEs in the free-living fraction was enhanced after chlorination. Considering multiple perspectives, including presence, mobility, and pathogenicity, chlorination led to a significant risk of the antibiotic resistome in the free-living fraction. Moreover, potential functions of ARGs, such as cell wall/membrane/envelope biogenesis, defense mechanisms, and transcription in the free-living fraction, were intensified following chlorination. Potential pathogens, including Pseudomonas aeruginosa, Pseudomonas alcaligenes, and Acinetobacter junii, were identified as the predominant hosts of multidrug resistance genes, with their increased abundances primarily contributing to the rise of the corresponding ARGs. Overall, alterations of hosts as well as enhancing mobility and biological functions could collectively aid the proliferation and spread of ARGs in the free-living fraction after chlorination. This study provides novel insights into antibiotic resistance evolution in size-fractionated bacteria community and offers a management strategy for microbiological safety in drinking water.

Dynamics of bacterioplankton communities in the estuary areas of the Taihu Lake: Distinct ecological mechanisms of abundant and rare communities.

As the crucial confluences of rivers and lakes, the estuary areas with varied hydrodynamic exchanges intensively affect the bacterioplankton communities, whereas the ecological characteristics of the bacterioplankton in the areas have not been well understood. Here, the distribution patterns and assembly mechanisms of bacterioplankton communities in the estuary areas of the Taihu Lake were investigated using high-throughput sequencing and multivariate statistical analyses. Our results showed obvious seasonal variations in bacterioplankton diversity and community composition, which had significant correlations with water temperature. Neutral and null models together revealed that stochastic processes (especially dispersal limitation) were the major processes in shaping the communities across different seasons. By contrast, heterogeneous selection in deterministic processes exhibited increased impacts on community assembly during summer and autumn, which was significantly related to the comprehensive water quality index (WQI) rather than any single factor. In this study, rare communities displayed more pronounced seasonal dynamics compared to abundant communities, likely due to their sensitivity towards environmental factors. Accordingly, the heterogeneous selection of deterministic processes largely shaped the rare communities. These results enriched our understanding of the assembly mechanisms of bacterioplankton communities in estuary areas and emphasized the specific co-occurrence patterns of abundant and rare communities.

Intimate Relationships Weaken Female Competition: Evidence from Phase-amplitude Coupling and Event-Related Potentials.

Competition, an essential component of social interaction, frequently occurs in daily life, and the impact of intimate relationships on women's competition has not yet been revealed. In this study, the visual target paradigm was used to explore the neural mechanisms underlying the regulation of female competitiveness by intimate relationships using event-related potential (ERP) data, time-frequency analysis, and brain functional connectivity. The research results indicate that, the P1, the N4, and the LPP were sensitive to the impact of intimate relationships on competition. Compared to competition between unfamiliar opposite-gender dyads, the average amplitudes of the N4 and LPP were higher in the late stage of competition between romantic partners. Compared to competition with strangers of the opposite gender, alpha band power was significantly higher when female individuals competed with their romantic partners. In addition, there was a positive correlation between the synchronization of activity in the frontal, parietal, and right temporal lobes of a female's brain and their degree of female engagement in competition. When a female individuals focused on the competition, activity synchronization was higher. The results indicate that competition with unfamiliar individuals of the opposite gender can make female focus on the competitive task, causing synchronous activation of corresponding brain regions. When competing with a romantic partner, women's focus decreases, their willingness to compete decreases, and the synchrony of brain functional connectivity decreases. This study suggests that intimate relationship weakens women's competitiveness, which is of significant importance for understanding high-quality intimate relationship and promoting the development of healthy competition.

Tertiary Wastewater Treatment Processes Can Be a Double-Edged Sword for Water Quality Improvement in View of Mitigating Antimicrobial Resistance and Pathogenicity.

Despite the high removal efficiency for chemical pollutants by tertiary wastewater treatment processes (TWTPs), there is no definite conclusion in terms of microbial risk mitigation yet. This study utilized metagenomic approaches to reveal the alterations of antibiotic resistance genes (ARGs), virulence factor genes (VFGs), their co-occurrence, and potential hosts during multiple TWTPs. Results showed that the TWTPs reduced chemical pollutants in wastewater, but the denitrifying biofilter (DB) significantly increased the absolute abundances of selected antibiotic-resistant bacteria and ARGs, and simultaneously elevated the relative abundances of ARGs and VFGs through the enrichment of multidrug resistance and offensive genes, respectively. Moreover, the co-occurrence of ARGs and VFGs (e.g., bacA-tapW, mexF-adeG) was only identified after the DB treatment and all carried by Pseudomonas. Then, the ultraviolet and constructed wetland treatment showed good complementarity for microbial risk reduction through mitigating antibiotic resistance and pathogenicity. Network and binning analyses showed that the shift of key operational taxonomic units affiliating to Pseudomonas and Acinetobacter may contribute to the dynamic changes of ARGs and VFGs during the TWTPs. Overall, this study sheds new light on how the TWTPs affect the antibiotic resistome and VFG profiles and what TWTPs should be selected for microbial risk mitigation.

Spatiotemporal distribution and fates of neonicotinoid insecticides during the urban water cycle in the lower reaches of the Yangtze River, China.

Neonicotinoid insecticides (NNIs) are the most popular insecticides worldwide, yet their spatiotemporal distribution and fates during the urban water cycle remain limited on a large watershed scale. Thus, we investigated ten kinds of NNIs in surface water from the lower reaches of the Yangtze River and hubs of the urban water cycle in all seasons. In brief, eight out of ten NNIs were detected, and thiamethoxam (THM), imidacloprid (IMI), and dinotefuran (DNT) were the most abundant NNIs in surface water, with concentrations of 0.29-48.15 ng/L, 1.69-20.57 ng/L, and 0.98-25.32 ng/L, respectively. The average concentrations of total NNIs in summer were 1.96-4.41 folds higher than those in other seasons. NNIs in the effluents of municipal wastewater treatment plants (WWTPs) were lower than those in surface water, while the average concentrations of total NNIs in the effluents of industrial WWTPs were 1.56-6.86 folds higher than those in surface water, indicating that insecticide production is an important source for NNIs in surface water. DNT was the most recalcitrant NNI in WWTPs, with an average removal efficiency of 49.89%, while in drinking water treatment plants (DWTPs), the removal efficiencies of most NNIs were limited, except for clothianidin (CLO) (90%). Risk assessment showed that NNIs posed medium or high risks to aquatic life, and DNT contributed 26.86-51.48% to the cumulative risks of detected NNIs. This study investigates the spatiotemporal distribution and risks of NNIs and provides information for the supervision of NNIs in the Yangtze River basin, China.

Stabilizing Effect of Soluplus on Erlotinib Metastable Crystal Form in Microparticles and Amorphous Solid Dispersions.

Microparticles (MPs) and amorphous solid dispersions (SDs) are effective methods to improve the dissolution of insoluble drugs. However, stability is a concern for these two high-energy systems, resulting from high surface area and amorphous polymorph, respectively. As an amphiphilic polymer, Soluplus (SOL) is usually used as a carrier in SDs. In this study, erlotinib microparticles (ERL MPs) and erlotinib solid dispersions (ERL SDs) were prepared with SOL by bottom-up technology and solvent evaporation. The solid-state properties of ERL MPs and ERL SDs were characterized by Differential Scanning Calorimetry (DSC), Powder X-Ray Diffraction (PXRD) and Scanning Electron Microscopy (SEM). The ERL MPs existed in a metastable crystal form A while the ERL SDs existed in an amorphous state. Fourier transform infrared spectroscopy (FT-IR) showed that there was a hydrogen bond interaction between the N-H group of ERL and the carbonyl group of SOL in ERL MPs and SDs. The dissolution profiles of ERL SDs and ERL MPs were improved significantly. ERL MPs showed better stability than ERL SDs in accelerated stability test. The discrepant stabilizing effects of polymer SOL in two systems may provide effective ideas for solubilization of insoluble drugs and the stability of drugs after recrystallization.

Influence of corn resistant starches type III on the rheology, structure, and viable counts of set yogurt.

The study intended to explore the influence of corn resistant starches type III (RS3s) prepared by autoclave, debranching, and microwave heat on the rheology, structure, and viable counts of set yogurt. The rheological analysis suggested that RS3s enhanced the elastic and viscous modulus of yogurt, and that microwave-heated RS was the most effective for improving viscoelasticity. Fitting the creep data using the Burger model showed that yogurt with microwave-heated RS increased the structural strength of yogurt, which displayed the highest instantaneous and viscoelastic deformations. The confocal laser scanning microscopy and scanning electron microscopy micrographs demonstrated that autoclaved and debranched RS3s formed large fragments and disrupted the continuity of the milk protein structure; however, microwave-heated RS evenly filled the gel network and formed an interpenetrating network with proteins. The bacterial count and acidity of yogurt indicated that microwave-heated and debranched RS3s promoted the growth of lactic acid bacteria and accelerated the fermentation process of yogurt. The results of this study demonstrated that microwave-heated RS is a favorable supplement to the microstructure and rheological properties of yogurt compared with autoclaved and debranched RS3s.

Enrichment and environmental availability of cadmium in agricultural soils developed on Cd-rich black shale in southwestern China.

The enrichment of cadmium (Cd) in black shale-derived soils is of increasing concern due to its wide occurrence, high Cd concentrations, and potential risks. However, characteristics of enrichment and environmental availability of Cd in these soils are not well understood, which has restricted pollution control and land management. In this study, agricultural soils with elevated Cd concentrations resulting from weathering of Cd-bearing black shale in southwestern China were collected and analyzed. The results showed that Cd could be retained in soils through mechanical inheritance and/or associated with secondary minerals and organic materials. Cd concentrations in soils of the study area ranged between 0.83 and 21.6 mg/kg (average of 5.20 mg/kg), exceeding the risk screening value for agricultural land in China. The heterogeneity of Cd in these soils was highly related to geochemical composition of parent rock and other natural factors. The 0.01 M CaCl2 and 0.05 M EDTA extraction showed that Cd in these soils had high environmental availability and potential risks. Mobile Cd pool (CaCl2 extractable Cd, average: 0.24 mg/kg) accounted for 0.07-38.9% of the total Cd, depending on soil pH. Mobilizable Cd pool (EDTA extractable Cd, average: 2.18 mg/kg) accounted for 22.0-100%. These results showed the significance of geochemical background on enrichment of Cd in soils, documented high environmental availability of Cd in black shale-derived soils, and influence of soil pH.

Heavy Metal Tolerance Genes Associated With Contaminated Sediments From an E-Waste Recycling River in Southern China.

Heavy metal pollution that results from electronic waste (e-waste) recycling activities has severe ecological environmental toxicity impacts on recycling areas. The distribution of heavy metals and the impact on the bacteria in these areas have received much attention. However, the diversity and composition of the microbial communities and the characteristics of heavy metal resistance genes (HMRGs) in the river sediments after long-term e-waste contamination still remain unclear. In this study, eight river sediment samples along a river in a recycling area were studied for the heavy metal concentration and the microbial community composition. The microbial community consisted of 13 phyla including Firmicutes (ranging from 10.45 to 36.63%), Proteobacteria (11.76 to 32.59%), Actinobacteria (14.81 to 27.45%), and unclassified bacteria. The abundance of Firmicutes increased along with the level of contaminants, while Actinobacteria decreased. A canonical correspondence analysis (CCA) showed that the concentration of mercury was significantly correlated with the microbial community and species distribution, which agreed with an analysis of the potential ecological risk index. Moreover, manually curated HMRGs were established, and the HMRG analysis results according to Illumina high-throughput sequencing showed that the abundance of HMRGs was positively related to the level of contamination, demonstrating a variety of resistance mechanisms to adapt, accommodate, and live under heavy metal-contaminated conditions. These findings increase the understanding of the changes in microbial communities in e-waste recycling areas and extend our knowledge of the HMRGs involved in the recovery of the ecological environment.

Spatial dynamics of bacterial community in chlorinated drinking water distribution systems supplied with two treatment plants: An integral study of free-living and particle-associated bacteria.

With the expansion of cities, the deterioration of drinking water quality undergoing complex and long-distance distribution is gaining increasing attention. However, spatial variations between free-living bacteria (FLB) and particle-associated bacteria (PAB) in chlorinated drinking water distribution systems (DWDSs) have not been fully explored, especially in complex water supply areas with multiple interconnected DWDSs. To fill this gap, this study utilized 16S rRNA approaches to characterize the spatial patterns of FLB and PAB in DWDSs with intersection regions. Based on distance-decay analysis, transportation distance is a potential driver of bacterial variation for both FLB (Pearson's r = -0.476, p < 0.01) and PAB. (Pearson's r = -0.352, p < 0.01). Moreover, the influence of transportation distance was further confirmed by a 1.20-99.45% decline in microbial contribution to the source of FLB and PAB communities in pipe water along the transportation pipelines. Meanwhile, significant difference (PERMANOVA, R2 = 0.14, p < 0.01) was found between FLB and PAB in DWDSs. Average proportions of Pseudomonas spp. were 59.84% and 45.59% for the PAB and intersection regions based on the 16S rRNA results, respectively, suggesting that PAB are potential reservoirs for high-risk bacteria, and a greater microbial risk may exist in intersection regions. In summary, transportation distance and pipeline intersection exerted significant impacts on the FLB and PAB in DWDSs. Therefore, precautionary strategies for controlling microbial risks that consider different microbial components and intersection regions in long-distance and multi-plant DWDSs should be implemented.

Integrated metagenomic and metatranscriptomic analyses of ultraviolet disinfection effects on antibiotic resistance genes and bacterial communities during wastewater treatment.

Ultraviolet (UV) disinfection is now widely implemented in wastewater treatment plants (WWTPs) worldwide, but its effect on antibiotic resistome of the surviving bacteria remains unclear. In this study, we employed high-throughput sequencing-based metagenomic and metatranscriptomic approaches to comprehensively elucidate the effects of UV disinfection on the shifts of bacterial community and antibiotic resistance genes (ARGs) on both DNA and mRNA levels in one WWTP. Metagenomic analyses revealed an insignificant change in the bacterial community after UV disinfection, while metatranscriptomic analyses showed that UV disinfection significantly changed the abundance of 13.79% of phyla and 10.32% of genera. In total, 38 ARG-like open reading frames (ORFs) and 327 ARG-like transcripts were identified in the DNA and RNA samples, respectively. The relative abundances of the total ARGs, each ARG type, and each ARG subtype also varied after UV disinfection. Additionally, UV disinfection significantly reduced the expression of total ARGs from 49.40 transcripts per kilobase of exon model per million mapped reads (TPM) to 47.62 TPM, and significantly changed the expression of 10.75% of ARG subtypes in wastewater (p < 0.05). Notably, the significant increase in the expression and obvious increase in the relative abundance of macrolide-lincosamide-streptogramin B (MLSB) resistance genes revealed that UV disinfection increases the potential health risk of MLSB resistance genes in wastewater. Moreover, potential host analyses of ARGs revealed the different preferences of antibiotic resistant bacteria (ARB) to ARGs. This study may shed new light on the underlying mechanism of the UV disinfection effect on antibiotic resistance.

Metagenomic insights into aniline effects on microbial community and biological sulfate reduction pathways during anaerobic treatment of high-sulfate wastewater.

For comprehensive insights into the change of sulfate reduction pathway responding to the toxic stress and the shift of microbial community and performance of sulfate reduction, we built a laboratory-scale expanded granular sludge bed reactor (EGSB) treating high-sulfate wastewater with elevated aniline concentrations from 0 to 480 mg/L. High-throughput sequencing and metagenomic approaches were applied to decipher the molecular mechanisms of sulfate reduction under aniline stress through taxonomic and functional profiles. The increasing aniline in the anaerobic system induced the accumulation of volatile fatty acids (VFA), further turned the bioreactor into acidification, which was the principal reason for the deterioration of system performance and finally resulted in the accumulation of toxic free sulfide. Moreover, aniline triggered the change of bacterial community and genes relating to sulfate reduction pathways. The increase of aniline from 0 to 320 mg/L enriched total sulfate-reducing bacteria (SRB), and the most abundant genus was Desulfomicrobium, accounting for 66.85-91.25% of total SRB. The assimilatory sulfate reduction pathway was obviously inhibited when aniline was over 160 mg/L, while genes associated with dissimilatory sulfate reduction pathways all exhibited an upward tendency with the increasing aniline content. The enrichment of aniline-resistant SRB (e.g. Desulfomicrobium) carrying genes associated with the dissimilatory sulfate reduction pathway also confirmed the underlying mechanism that sulfate reduction turned into dissimilation under high aniline condition. Taken together, these results comprehensively provided solid evidence for the effects of aniline on the biological sulfate reduction processes treating high-sulfate wastewater and the underlying molecular mechanisms which may highlight the important roles of SRB and related sulfate reduction genes during treatment.

Occurrence, spatial distribution and risk assessment of organophosphate esters in surface water from the lower Yangtze River Basin.

Organophosphate esters (OPEs) are extensively used as flame retardants and plasticizers in China; however, their potential carcinogenicity causes great concern. To date, their environmental distribution in water samples from the lower Yangtze River Basin still remains uncharacterized. This study systematically investigated the occurrence and spatial distribution of 13 OPEs, as well as their associated potential risks, in water samples from the lower Yangtze River and its 88 major inflowing rivers. The total OPE (ΣOPEs) concentrations ranged from 55.6 to 5071 ng/L, with a median of 144 ng/L. Among them, halogenated OPEs were the dominant group with an average of 61.6%, and tris(1-chloro-2-propyl) phosphate (12.6-450 ng/L, median: 53.38 ng/L) and tris(2-choroethyl) phosphate (11.0-1202 ng/L, median: 36.4 ng/L) were the most abundant OPEs. Significantly different concentrations were found with spatial variations (p < 0.01), and were higher in southern cities than in northern cities of the lower Yangtze River Basin. Principal component analysis with multiple linear regression and Spearman correlations showed that the main sources were likely emission of vehicular and marine traffic. Ecological risk analysis showed that the risk quotient (RQ) values of samples remained below 1, but the percentage of 0.1 < RQ ≤ 1 was 26.9%, indicating a medium risk of OPEs in water samples. Moreover, ethylhexyl diphenyl phosphate predominantly contributed to the ecological risk, accounting for >89.2% of the total ecological risk of ΣOPEs. However, the total non-carcinogenic and carcinogenic risks of ΣOPEs were negligible at the detected concentrations, even in a high exposure scenario. The risks from major inflowing rivers of the lower Yangtze River were almost one order of magnitude higher than those of the mainstream lower Yangtze River.

Disinfection characteristics of Pseudomonas peli, a chlorine-resistant bacterium isolated from a water supply network.

Lack of microbial contamination is crucial for drinking water quality and safety. Chlorine-resistant bacteria in drinking water distribution systems pose a threat to drinking water quality. A bacterium was isolated from an urban water supply network in northern China and identified as Pseudomonas peli by 16S rDNA gene analysis. This P. peli strain had high chlorine tolerance. The CT value (the product of disinfectant concentration and contact time) to achieve 3 lg unit (i.e. 99.9%)-inactivation of this P. peli isolate was 51.26-90.36 mg min/L, inversely proportional to the free chlorine concentration. Chlorine dioxide could inactivate the bacterium faster and more efficiently than free chlorine, as shown by flow cytometry. Thiazole orange plus propidium iodide staining indicated that free chlorine and chlorine dioxide inactivated P. peli primarily by disrupting the integrity and permeability of the cell membrane. The P. peli was also sensitive to ultraviolet (UV) radiation; a UV dose of 40 mJ/cm2 achieved 4 lg unit (99.99%)-inactivation. The Hom model was more suitable for analyzing the disinfection kinetics of P. peli than the Chick and Chick-Watson models.