QSAR for biotoxication of aromatic compounds

MANY congeneric chemicals of aromatic hydrocarbons are toxic organic materials. This note uses some available molecular descriptors such as the energy of molecular orbital and the molecular connectivity index to analyse the biotoxicities and the structure-effect relationships of aromatic compounds on aquatic organism and terrestrial mammal in the view of molecular structure and energy with the method of quantitative structure-activity relationship (QSAR),

Glycine-β-cyclodextrin-assisted cometabolism of phenanthrene and pyrene by Pseudomonas stutzeri DJP 1 from marine sediment

Cometabolic degradation is currently an effective and extensively way to remove high molecular weight polycyclic aromatic hydrocarbons(HMW-PAHs).Unfortunately,due to low bio-accessibility and high biotoxicity,the cometabolic degradation rate of HMW-PAHs is limited.Glycine-β-cyclodextrin(GCD)was obtained through amino modification ofβ-cyclodextrin(BCD)and added to cometabolic system of phenanthrene(PHE)and pyrene(PYR)to assist PYR biodegradation.Results show that the addition of GCD(100 mg/L)effectively improved the removal rate of PYR(20 mg/L)by 42.3%.GCD appeared to increase the bio-accessibility and reduce the biotoxicity of PHE and PYR,and then promoted the growth of Pseudomonas stutzeri DJP1 and stimulated the elevation of dehydrogenase(DHA)and catechol 12 dioxygenase(C12O)activities.The phthalate metabolic pathway was accelerated,which improved the cometabolic degradation.This study provided a new reference for the cometabolic degradation of HMW-PAHs.

Unravelling biotoxicity of graphdiyne:Molecular dynamics simulation of the interaction between villin headpiece protein and graphdiyne

Recently,there has been a growing prevalence in the utilization of graphdiyne(GDY)in the field of biomedicine,attributed to its distinctive physical structure and chemical properties.Additionally,its biocompatibility has garnered increasing attention.However,there is a lack of research on the biological effects and physical mechanisms of GDYprotein interactions at the molecular scale.In this study,the villin headpiece subdomain(HP35)served as a representative protein model.Molecular dynamics simulations were employed to investigate the interaction process between the HP35 protein and GDY,as well as the structural evolution of the protein.The data presented in our study demonstrate that GDY can rapidly adsorb HP35 protein and induce denaturation to one of the a-helix structures of HP35 protein.This implies a potential cytotoxicity concern of GDY for biological systems.Compared to graphene,GDY induced less disruption to HP35 protein.This can be attributed to the presence of natural triangular vacancies in GDY,which prevents p–p stacking action and the limited interaction of GDY with HP35 protein is not conducive to the expansion of protein structures.These findings unveil the biological effects of GDY at the molecular level and provide valuable insights for the application of GDY in biomedicine.

Degradation mechanisms of oxytetracycline in the environment

Over the past few decades,the usage of oxytetracycline(OTC),a kind of antibiotic,has increased with the development of aquaculture and livestock breeding.However,about 30–90%of the applied antibiotics are excreted as the parent compounds into the environment,especially with the application of animal manure to agricultural fields.This large influx of antibiotics may lead to the destruction of the natural microbial ecological community and pose great threats to human beings through the food chain.Therefore,the fate and toxicity of OTC in the environment are issues of great concern.Degradation of OTC,including the non-biodegradation and biodegradation,and the biological toxicity of its degradation products or metabolites,are reviewed in this paper.The non-biodegradation pathways include hydroxylation,quinonization,demethylation,decarbonylation,dehydration and secondary alcohol oxidation.Light(particularly UV light),pH and oxidizing substances play important roles in non-biodegradation.Biodegradation products include 4-epi-OTC(EOTC),2-acetyl-2-decarboxy-amido-OTC(ADOTC),α-apo-OTC andβ-apo-OTC.EOTC is an epimer and identied except for the configuration of the C4 dimethylamino group of OTC.Temperature and pH are the main factors affecting biodegradation pathways of OTC.In addition,this review discusses concerns over the biological toxicity of OTC degradation products.

Cathode catalyst prepared from bacterial cellulose for ethanol fermentation stillage treatment in microbial fuel cell

Bacterial cellulose doped with P and Cu was used as a catalyst for a microbial fuel cell(MFC) cathode,which was then used to treat ethanol fermentation stillage from food waste.Corresponding output power,coulombic efficiency(CE),and biological toxicity were detected.Through a series of characterization experiments,the addition of the cathode catalyst was found to improve catalytic activity and accelerate the consumption of the substrate.The resulting maximum output power was 572.16 mW·m^(-2).CE and the removal rate of chemical oxygen demand(COD) in the fermentation stillage by P-Cu-BC reached 26% and 64.5%,respectively.The rate of biotoxicity removal by MFC treatment reached 84.7%.The aim of this study was apply a novel catalyst for MFC and optimize the treatment efficiency of fermentation stillage.

Impact of Suspended Particles and Enhancement Techniques on Ultraviolet Disinfection of a Secondary Effluent

The concentration of suspended solids in the secondary effluent often varies widely, leading to frequent adjustment of the UV dosage to meet the disinfection criterion. In addition, a desired disinfection rate is difficult to achieve sometimes. The authors studied the particle size distribution, contribution of particle-associated Fecal Coliform (F.C.), and their influences on UV disinfection. A combined disinfection process (chlorination with a subsequent UV disinfection) was tested to improve the disinfection effect. The results indicated that the content of suspended solids, especially that of large particles, has a strong impact on UV disinfection efficiency; D>10 μm particles associated F.C. are difficult to be disinfected and are the main part of the tailings of F.C. inactivation curves. Pre-chlorination could decrease the number of particles in the secondary effluent and transform the large particles into small ones, reducing the influence of particles on UV disinfection and enhancing the resistance ability of the combined process to particle loading.

Comparative evaluation of SPE methods for biotoxicity assessment of water and wastewater:Linkage between chemical extracting efficiency and biotoxicity outcome

Biotoxicity assessment results of environmental waters largely depend on the sample extraction protocols that enrich pollutants to meet the effect-trigger thresholds of bioassays.However,more chemical mixture does not necessarily translate to higher combined biotoxicity.Thus,there is a need to establish the link between chemical extracting efficiency and biotoxicity outcome to standardize extraction methods for biotoxicity assessment of environmental waters.This study compares the performance of five different extraction phases in solid phase extraction(SPE),namely HLB,HLB+Coconut,C18 cartridge,C18 disk and Strata-X,and evaluated their chemical extracting efficiencies and biotoxicity outcomes.We quantitatively assessed cytotoxicity,acute toxicity,genotoxicity,estrogenic activity,and neurotoxicity of the extracts using in vitro bioassays and characterized the chemical extracting efficiencies of the SPE methods through chemical recoveries of 23 model compounds with different polarities and total organic carbon.Using Pareto ranking,we identified HLB+Coconut as the optimal SPE method,which exhibited the highest level of water sample biotoxicity and recovered the most chemicals in water samples.We found that the biotoxicity outcomes of the extracted water samples significantly and positively correlated with the chemical extracting efficiencies of the SPE methods.Moreover,we observed synchronous changing patterns in biotoxicity outcome and chemical extracting efficiencies in response to increasing sample volumes per cartridge(SVPC)during SPE.Our findings underscore that higher chemical extracting efficiency of SPE corresponds to higher biotoxicity outcome of environmental water samples,providing a scientific basis for standardization of SPE methods for adequate assessment of biotoxicities of environmental waters.

Biotoxicity dynamic change and key toxic organics identification of coal chemical wastewater along a novel full-scale treatment process

It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotoxicity reduction of industrial wastewater are still limited.In this study,the toxic organics removal and biotoxicity reduction of coal chemical wastewater(CCW)along a novel full-scale treatment process based on the pretreatment process-anaerobic process-biological enhanced(BE)process-anoxic/oxic(A/O)process-advanced treatment process was evaluated.This process performed great removal efficiency of COD,total phenol,NH_(4)^(+)-N and total nitrogen.And the biotoxicity variation along the treatment units was analyzed from the perspective of acute biotoxicity,genotixicity and oxidative damage.The results indicated that the effluent of pretreatment process presented relatively high acute biotoxicity to Tetrahymena thermophila.But the acute biotoxicity was significantly reduced in BE-A/O process.And the genotoxicity and oxidative damage to Tetrahymena thermophila were significantly decreased after advanced treatment.The polar organics in CCW were identified as the main biotoxicity contributors.Phenols were positively correlated with acute biotoxicity,while the nitrogenous heterocyclic compounds and polycyclic aromatic hydrocarbons were positively correlated with genotoxicity.Although the biotoxicity was effectively reduced in the novel full-scale treatment process,the effluent still performed potential biotoxicity,which need to be further explored in order to reduce environmental risk.

Brominated flame retardants in surface sediment from Western Guangdong,South China:Occurrence,distribution and toxicity in Caenorhabditis elegans

Sediment is the ultimate sink of environmental pollutants.A total of 128 surface sediment sampleswere collected from8 rivers and 3 reservoirs in Maoming City,Guangdong Province.This study assessed the content and distribution of brominated flame retardants in sediments.The acute toxicity effects of tetrabromobisphenol A(TBBPA)and hexabromocyclododecane(HBCDs)in sediments were evaluated using Caenorhabditis elegans as model organisms.The concentration of TBBPA in sediments ranged from not detected(ND)to 12.59μg/kg andwas mainly distributed in the central area,whichwas affected by the emission of TBBPA from residential and factory.The concentration of HBCDs ranged from ND to 6.31μg/kg,and the diastereoisomer distribution was consistent,showing a trend close to the South China Sea.The composition pattern of HBCDs in the surface sediments from rivers were 41.73%-62.33%,7.89%-25.54%,and 18.76%-40.65%forα-,β-,andγ-HBCD,respectively,and in the sediments from reservoirs were 26.15%-45.52%,7.44%-19.23%,and 47.04%-61.89%forα-,β-,andγ-HBCD,respectively.When the sum of concentrations of TBBPA and HBCD in sediments were above high levels,reactive oxygen species in nematodes significantly increased,resulting in an oxidative stress response.Intestinal permeabilitywas also enhanced,causing intestinal damage.In addition,in terms of this study,TBBPA had a greater impact on biotoxicity compared to HBCDs,and more attention should be paid to the toxic effects of the river ecosystem organisms in Maoming City,Guangdong Province.This study can complement the pollution database in the study area and provide basic data for pollution control.

Achieving biodegradability enhancement and acute biotoxicity removal through the treatment of pharmaceutical wastewater using a combined internal electrolysis and ultrasonic irradiation technology

Actual pharmaceutical wastewater was treatedusing a combined ultrasonic irradiation (US) and iron/cokeinternal electrolysis (Fe/C) technology. A significantsynergetic effect was observed, showing that ultrasonicirradiation dramatically enhanced the chemical oxygendemand (COD) removal efficiencies by internal electrolysis.The effects of primary operating factors on CODremoval were evaluated systematically. Higher ultrasonicfrequency and lower pH values as well as longer reactiontime were favorable to COD removal. The ratio ofbiochemical oxygen demand (BOD) and COD (B/C) ofthe wastewater increased from 0.21 to 0.32 after US-Fe/Ctreatment. An acute biotoxicity assay measuring theinhibition of bioluminescence indicated that the wastewaterwith overall toxicity of 4.3 mg-Zn^(2+)·L^(-1) wasreduced to 0.5 mg-Zn^(2+)·L^(-1) after treatment. Both the rawand the treated wastewater samples were separated andidentified. The types of compounds suggested that theincreased biodegradability and reduced biotoxicityresulted mainly from the destruction of N,N-2 dimethylformamide and aromatic compounds in the pharmaceuticalwastewater.

Biochar mitigates the biotoxicity of heavy metals in livestock manure during composting

The addition of biochar could mitigate the bioavailability of heavy metals during livestock manure composting.However,the main action mechanism of biochar,such as how it worked,was ambiguous.Therefore,in this study,materials(biochar,alkali modified biochar,pretreated cotton ball)were added by embedding with nylon mesh bags to explore the adsorption performance of added materials and its influence on the composting process.The results showed that embedded materials promoted the formation of humic acid and reduced the distribution proportion of bioavailable fraction of heavy metals during composting(Cu:at least 15.72%;Zn:at least 33.44%).The surface of biochar extracted from composting contained attachments,however,the attachment of heavy metal was not detected and functional groups on the materials did no change significantly.This indicated that the addition of biochar did not directly adsorb heavy metals.Most notably,the microbial network changed after embedding materials,and the succession of microbial community promoted the formation of humic acid.Ultimately,structural equation models verified that embedded materials promoted the formation of humic acid through stable microbial groups,thereby accelerating the passivation of heavy metals during composting.This study provides theoretical and technical supports for mitigating the biotoxicity of heavy metals by biochar during composting.

Evaluating the effectiveness of marine actinobacterial extract and its mediated titanium dioxide nanoparticles in the degradation of azo dyes

Aim of the present study was to synthesize titanium dioxide nanoparticles （YiO2 NPs） from marine actinobacteria and to develop an eco-friendly azo-dye degradation method. A total of five actinobacterial isolates were isolated from Chennai marine sediments, Tamilnadu, India and analyzed for the synthesis of TiO2 NPs using titanium hydroxide. Among these, the isolate PSV 3 showed positive results for the synthesis of TiO2 NPs, which was confirmed by UV analysis. Further characterization of the synthesized TiO2 NPs was done using XRD, AFM and FI＇-IR analysis. Actinobacterial crude extract and synthesized TiO2 NPs was found efficient in degrading azo dye such as Acid Red 79 （AR-79） and Acid Red 80 （AR-80）. Degradation percentage was found to be 81% for AR-79, 83% for AR-80 using actinobacterial crude extract and 84% for AR-79, 85% for AR-80 using TiO2 NPs. Immobilized actinobacterial ceils showed 88% for AR-79 and 81% for AR- 80, dye degrading capacity. Degraded components were characterized by FT-IR and GC-MS analysis. The phytotoxicity test with 500 μg/mL of untreated dye showed remarkable phenotypic as well as cellular damage to Tagetes erecta plant. Comparatively no such damage was observed on plants by degraded dye components. In biotoxicity assay, treated dyes showed less toxic effect as compared to the untreated dyes.

Characterizations and Photothermal Properties of Narrow Bandgap Conjugated Polymer Nanoparticles

Photothermal therapy(PTT)is a minimally invasive treatment that kills cancer cells by converting photon energy into heat.The past few decades have witnessed the booming development of photothermal materials,mainly focusing on precious metal nanomaterials and carbon nanomaterials,such as nanogold and silver and nanocarbon materials for near-infrared(NIR)light-triggered PTF.As precious metals are expensive and potentially harmful to humans,exploration and development of a new type of photothermal materials has become a research hotspot in this field.Herein,we report narrow bandgap conjugated polymer nanoparticles(PDPP NPs)based on pyrrolo[3,4-c]pyrrole-1,4-dione(DPP)with intense NIR absorption at 900 nm,as well as a photothermal energy conversion efficiency of 75%.This polymer nanoparticle is essentially non-toxic,as the cell viability of mouse remained more than 90%,even when the concentration of PDPP NPs was at 0.5 mg·mL^-1.

Biotoxicity evaluation of zinc oxide nanoparticles on bacterial performance of activated sludge at COD,nitrogen,and phosphorus reduction

The unique properties and growing usage of zinc oxide nanoparticles increase their release in municipal wastewater treatment plants.Therefore,these nanoparticles,by interacting with microorganisms,can fail the suitable functioning of biological systems in treatment plants.For this reason,research into the toxicity of ZnO is urgent.In the present study,the toxicity mechanism of ZnO-NPs towards microbial communities central to granular activated sludge(GAS)performance was assessed over 120-day exposure.The results demonstrate that the biotoxicity of ZnO-NPs is dependent upon its dosage,exposure time,and the extent of reactive oxygen species(ROS)production.Furthermore,GAS performance and the extracellular polymeric substances(EPS)content were significantly reduced at 50 mg/L ZnO-NPs.This exposure led to decreases in the activity of ammonia monooxygenase(25.2%)and nitrate reductase(11.9%)activity.The Field emission scanning electron microscopy images confirmed that ZnO-NPs were able to disrupt the cell membrane integrity and lead to cell/bacterial death via intracellular ROS generation which was confirmed by the Confocal Laser Scanning Microscopy analysis.After exposure to the NPs,the bacterial community composition shifted to one dominated by Gram-positive bacteria.The results of this study could help to develop environmental standards and regulations for NPs applications and emissions.

Oxidation and biotoxicity assessment of microcystin-LR using different AOPs based on UV, O3 and H2O2

Microcystin-LR attracts attention due to its high toxicity, high concentration and high frequency. The removal characteristics of UV/H2O2 and O3/H2O2 advanced oxidation processes and their individual process for MC-LR were investigated and compared in this study. Both the removal efficiencies and rates of MC-LR as well as the biotoxicity of degradation products was analyzed. Results showed that the UV/H2O2 process and O3/H2O2 were effective methods to remove MC-LR from water, and they two performed better than UV-, O3-, H2O2-alone processes under the same conditions. The effects of UV intensity, H2O2 concentration and O3 concentration on the removal perfomlance were explored. The synergistic effects between UV and H2O2, O3 and H2O2 were observed. UV dosage of 1800 mJ·cm^-2 was required to remove 90% of 100μg.L^-1 MC-LR, which amount significantly decreased to 500 mJ.cm^-2 when 1.7mg·L^-1 H2O2 was added. 0.25 mg.L^-1 O3, or 0.125 mg·L^-1 O9 with 1.7 mg·L^-1 H2O2 was needed to reach 90% removal efficiency. Furthermore, the biotoxicity results about these UV/H2O2, O3/H2O2 and O3-alone processes all present rising trends with oxidation degree of MC-LR. Biotoxicity of solution, equ valent to 0.01 mg·L^-1 Zn^2＋,ratsed to 0.05 mg.L Zn after UV/H2O2 or O3/H2O2 reaction. This phenomenon may be attributed to the aldehydes and ketones with small molecular weight generated during reaction. Advice about the selection of MC-LR removal methods in real cases was provided.

Perylenediimide chromophore as an efficient photothermal agent for cancer therapy

Photothermal agents with improved bioavailabilities can generate heat from near-infrared light, which has been efficiently used for in vivo photothermal therapy （PTT） for cancer, with minimum tissue invasion. Strategies for developing organic near-infrared-absorbing molecules for phototfiermal cancer therapy have drawn intensive attention among academic investigators. However, conventional organic nearinfrared-absorbing molecules may not only have complex synthesis procedures, but also easily suffer from photobleaching under light irradiation. These drawbacks might lead to an increase in the synthesis cost, and elicit a risk of side effects in PTF. Thus, it is essential to devise an organic photothermal agent with stable phototbermal capacity, which involves a facile synthesis process. In this study, incorporating a secondary amine group （donor） in the bay regions of perylenediimides （PDls） could lead to a 150-nm bathochromic shift of the absorption maximum. Next, a modification of poly（ethylene glycol） （PEG） at the periphery of the chromophore renders the targeted macromolecule PDI-PEG highly water-soluble, and capable of intense absorption in the near-infrared region. The self-assembled PDl-based nanoparti- des （PDI-NPs） have a size of 55 nm in aqueous solutions. PDI-NPs with excellent photostability possess a high photothermal conversion efficiency of up to 43% ± 2%. Finally, PDI-NPs allow for efficient in vitro and in vivo photothermal cancer therapy. Meanwhile, PDI-NPs exhibit quite low cytotoxicity and no biotoxicity on major organs in vivo. Thus, these easily-manufactured PDI-NPs can serve as extremely stable photothermal agents for efficient photothermal cancer therapy.

Evaluating the biotoxicity of surface water in a grassy lake in North China

The biological toxicity of aquatic ecosystems should be considered when assessing the effects of toxicity on the water environment.The aim of this study was to identify the main pollutants in the Baiyangdian(BYD)and the factors that contribute to biological toxicity.We determined various physical and chemical indicators in the surface water of the BYD,including nutrients and heavy metals,and the biological toxicity.We also explored the sources of the main pollutants and how the pollutants contributed to toxicity in the lake,using correlation analysis and an index of the biological toxicity.The results showed that total nitrogen(TN),ammoniacal nitrogen(NH4^(+)-N),chromium(Cr),and zinc(Zn)were the main pollutants in the BYD surface water.The average concentration of Cr was 2.3 times greater than the Class V threshold,and the concentrations at about 65%of the sampling points,mainly those in the southern part of the BYD,exceeded the threshold standard.The average concentration of Zn was 1.25 times higher than the Class V threshold,with the concentrations of about 35%of the samples greater than the threshold concentration.The integrated toxicity of the surface water to luminescent bacteria ranged from 0.51%to 58%,and averaged 24.07%,which was within the range of moderate toxicity.The inhibition rates were high near Diantou(59%)and Duan(51.6%).The pollutant levels in the BYD tend to be related to the population density,with pollution mainly caused by sewage and domestic garbage,with little influence from local industries.Cr and TN were strongly correlated,but the biological toxicity was not correlated with any of the individual environmental indicators,which suggests that the toxicity in the surface water of the BYD reflected the combined effects of the environmental factors,rather than a single factor.The information from this study,about the main pollutants and the relationships between the physical and chemical properties of the surface water in the BYD,can be used to support plans for restoring the BYD.

Glutathione-triggered non-template synthesized porous carbon nanospheres serve as low toxicity targeted delivery system for cancer multi-therapy

Nano material based drug delivery system have received great attention in clinical application due to their high therapeutic efficacy and lower side effects than classical method,multi-functional nanomaterial also have shown the excellent performance at cancer theranostic and durg tracking in vivo and in vitro.However,most of these works are influenced by the bio-toxicity of applied nanomaterials,which could influence the diagnostic results and treatment effect.Therefore,we have prepared a high biocompatibility porous carbon nanospheres(PCNs) based nano-system(PCN-siRNA-DOX-FA) for targeted drug delivery and the ranostic.The surface modifications have increased dispersion and stability of the PCNs,and folic acid(FA) had enhanced the active target ability for FA receptor positive cell lines.Moreover,through the siRNA structure and doxorubicin(DOX) loading,biological and chemical combined multi-therapy was achieved in cancerous cells.This constructed nano-system could positively improve the biotoxicity problem of nanomaterial and provide a potential platform for clinical cancer theranostic applications.

Comparison of different algicides on growth of Microcystis aeruginosa and microcystin release, as well as its removal pathway in riverways

Eutrophication with a large number of Microcystis aeruginosa commonly occurs worldwide, thereby threatening the aquatic ecosystem and human health. In this study, four kinds of algicides were tested to explore their influence on cell density and chlorophyll-a of M. aeruginosa. Results showed that aluminum silicate agent, which inhibited more than 90% cell growth compared with the control group, demonstrated the strongest inhibition effect immediately on M. aeruginosa growth. Furthermore, the production and release of microcystin （MC）-LR were investigated. Aluminum silicate, CuSO4, and Emma-11 were more effective than pyrogallic acid in disrupting the cells of M. aeruginosa, thereby increasing the extracellular MC-LR concentration. Aluminum silicate caused the highest extracellular MC-LR concentration of more than 45 mg·L^-1. Biotoxicity was also detected to evaluate the environmental risks of MC-LR release, which were related to the usages of different algicides. Extracellular MC-LR concentration mostly increased when the biotoxicity of algae solution increased. The experiments were also designed to reveal the effects of physical conditions in riverways, such as natural sunlight, aeration and benthal sludge, on MC-LR degradation. These findings indicated that UV rays in sunlight, which can achieve a MC-LR removal efficiency of more than 15%, played an important role in MC-LR degradation. Among all the physical pathways of MC-LR removal, benthal sludge adsorption presented the optimal efficiency at 20%.