Study on the Ecotoxicity of Three Veterinary Antibiotics Against Alfalfa (Medicago sativa L.)

[Objectives]This study was conducted on the effects of veterinary antibiotics on pasture growth.[Methods]With alfalfa ( Medicago sativa L.) as an experimental material and oxytetracycline,chlortetracycline and enrofloxacin as experimental contaminants,the effects of the three veterinary antibiotics on the germination percentage,germination energy,germination index and vigor index of alfalfa seeds and on the plant height and root length of alfalfa seedlings were study at the concentration gradient of 50,100,150,200 and 250 mg/L,respectively.[Results]The oxytetracycline treatments had no significant effect on the germination percentage of alfalfa seeds,but promoted its germination index.The chlortetracycline treatment solutions and enrofloxacin treatment solutions promoted the germination percentage,germination energy and germination index of alfalfa.The three antibiotics significantly inhibited the vigor index of alfalfa seeds,and had significant inhibitory effects on root length and plant height.[Conclusions]These results provide an important basis for studying the ecotoxicity of veterinary antibiotics on pasture.

Assessing Ecotoxicity in Marine Environment Using Luminescent Microalgae: Where Are We At?

Nowadays, microalgae are particularly used to assess the environmental impact of contaminants in aquatic systems. Naturally present in some algal species, bioluminescence is highly used in application fields related to environmental monitoring. Bioluminescent dinoflagellates have played a pivotal role in this domain. When exposed to heavy metals or toxic organic compounds, bioluminescent dinoflagellates have the capacity to decrease light emission. In addition, new molecular tools allow the possibility to produce genetically modified microorganisms which are able to perform luminescence. Combined with the luciferase reporter gene, two main genetic constructions can be employed. Activation of a specific inducible promoter induces the luminescence gene transcription and this signal increases over time. Constitutive promoters result in a high basal expression level of the reporter gene. During exposure to a potential toxic pollutant, the basal expression level will decrease due to the toxic effect. Toxicity bioassays based on engineered luminescent Chlorophyta microalgae are among the most sensitive tests and are an invaluable complement to classical toxicity assays.

<i>N</i>-Acetylated Gemini Surfactants: Synthesis, Surface-Active Properties, Antifungal Activity, and Ecotoxicity Bioassays

A series of N-acetylated cationic gemini surfactants (3a-e) having dimeric structures derived from tertiary amines were synthesized. Their antifungal potency and surface properties were determined. It also studied the acute toxicity of the molecule with the best performance and the best water solubility (3e) through Chlorella vulgaris and Daphnia magna bioassays. The results were compared to those obtained for a commercially available reference compound 2-(thiocyanomethylthio) benzothiazole (TCMTB). Parameters such as surface tension (&#978CMC), critical micelle concentration (CMC), surface excess concentration (Γ), and area per molecule (A) were determined. The resulting values indicated that the five gemini surfactants are characterized by good surface-active and self-aggregation properties. All surfactants were tested to evaluate their antifungal activity. Six fungal strains were used to conduct the study. The minimum inhibitory concentration (MIC) value was measured by the fungal growth inhibition. The results of the MICs were compared with two commercially available reference compounds (Fluconazole and TCMTB). The least active molecule was 3e, but 3b and 3d were found to be the most potent compounds with a similar activity for all strains. Candida albicans was the most sensitive one. In contrast, Aspergillus niger was resistant. Ecotoxicity of gemini 3e was assessed: the commercial formulation (TCMTB) was between three and four orders of magnitude more toxic than the gemini one for the biological species tested.

Essentiality, Fate, Ecotoxicity, and Health Effects of Xanthates and Xanthates Based-Compounds—A Review

Xanthates are organic synthesized substances with a potentially wide range of applications. They may serve as essential components of many compounds or materials that also play a vital role in various industrial and socio-economic processes. Addressing the question of the use of xanthates without considering their toxicity, and their decomposition process and products would be ecologically and healthily less sustainable. To date, related information is still dispersed and less known to the public. Therefore, this work provides a comprehensive overview of the existing information on the essentiality, fate, ecotoxicity, and health effects of xanthates and associated compounds. According to available information from scientific, technical, and professional circles, xanthates are diverse, usually with a carbon chain of two to six carbon atoms. They play a crucial role in the sectors of the mining and mineral processing industry, agriculture, wastewater treatment, metal protection, rubber vulcanization, the pharmaceutical industry, and medicine. Xanthates’ degradation under different factors and mechanisms, which determine their fate in the environment, leads to the formation of toxic substances, mainly carbon disulfide, carbonyl sulfide, hydrogen sulfide, and hydrogen peroxide. Xanthates and xanthates degradation products are seriously hazardous to humans, animals, soil and aquatic organisms, enzymatic system, etc. Simultaneous exposure to xanthates and metals results in the magnification or reduction of their toxicity level, depending on the exposed organisms. Such toxicological dimensions should attract more scientific and public attention for more safe production, use, storage, and disposal of xanthates. Due to the high affinity of xanthates for metal, xanthates-modified compounds are efficient metal chelating agents. Such a property should be explored to develop potentially low-cost and effective alternatives for metal removal and recovery from contaminated media. The same applies to developing appropriate methods for the evaluation and management of the simultaneous presence of xanthates and metals in the environment.

Water Quality and Ecotoxicity Assessment in Surface Waters from Cubatao River and Surroundings,Sao Paulo,Brazil

The monitoring of water bodies means the attempt of protecting vulnerable groups of organisms inhabiting streams and rivers. Industrial and domestic discharges may worsen the water quality and affect biological balance, structure and the functioning of the ecosystem. Cubat?o City, is one of the largest industrial centers in Brazil and in Latin America, where the constant discharge of effluents into Cubat?o River and its tributaries caused a degradation scenario in the hydrographic basin of the region. The objective of this study was to evaluate the acute and chronic effects of surface water from Cubat?o River and two of its tributaries (Perequê and Pil?es) by ecotoxicological assays. In addition, physical chemical parameters were analyzed. Ceriodaphnia dubia and Vibrio fischeri were exposed-organisms during the studied period. The study was conducted between 2010 and 2011 in four campaigns and nine sites along the basin of Cubat?o River. The ecotoxicity was measured by Vibrio fischeri bioluminescence, EC50 values ranging from 31.25% to 71.61%. In contrast, based on a bioequivalence t-test statistical analysis, the results obtained with Ceriodaphnia dubia revealed no toxicity in the sampling sites. A critical analysis of raw data of luminescence was carried out showing higher values during the 2nd campaign. From the numbers obtained for physical-chemical parameters P5 was far the worst due to chlorides, hardness and conductivity. From the Pearson correlation analysis carried out with toxicity to V. fischeri and the physical chemical parameters, the dissolved oxygen in water resulted in a moderate positive correlation. Sediment contamination was also demonstrated in the region.

Palm oil biodiesel:An assessment of PAH emissions,oxidative potential and ecotoxicity of particulate matter

This work assessed the impact of fuelling an automotive engine with palm biodiesel(pure,and two blends of 10%and 20%with diesel,B100,B10 and B20,respectively)operating under representative urban driving conditions on 17 priority polycyclic aromatic hydrocarbon(PAH)compounds,oxidative potential of ascorbic acid(OP^(AA)),and ecotoxicity through D aphnia pulex mortality test.PM diluted with filtered fresh air(WD)gathered in a minitunel,and particulate matter(PM)collected directly from the exhaust gas stream(W/oD)were used for comparison.Results showed that PM collecting method significantly impact PAH concentration.Although all PAH appeared in both,WD and W/oD,higher concentrations were obtained in the last case.Increasing biodiesel concentration in the fuel blend decreased all PAH compounds,and those with 3 and 5 aromatic rings were the most abundant.Palm biodiesel affected both OP^(AA)and ecotoxicity.While B10 and B20 exhibited the same rate of ascorbic acid(AA)depletion,B100 showed significant faster oxidation rate during the first four minutes and oxidized 10%more AA at the end of the test.B100 and B20 were significantly more ecotoxic than B10.The lethal concentration LC50 for B10 was 6.13 mg/L.It was concluded that palm biodiesel decreased PAH compounds,but increased the oxidative potential and ecotoxicity.

Survival of Pseudomonas fluorescence X16(luxAB)Strain in Soils Accumulated with Mixed Rare Earth Elements

Rare earth elements(REE)are applied as micro-fertilizer in large scale in China and there is growing concern about the environmental effects of REE accumulation in soils. Accumulation of REE was simulated in lab by adding REE to three soils and the survival of Pseudomonas fluorescence X16 strain marked with luxAB gene in soils was detected. Curvilinear regression method was applied to analyze the survival pattern. The stimulation values, EC_(50) and NOEC values for X16 strain were calculated to compare the toxic intensity of REE in different soils. The stimulation(peak)values in red soil, yellow fluovo-aquic soil and yellow cinnamon soil, are 11.55～18.08,(0～2.13), 2.37～4.62 mg·kg^(-1) , respectively. EC_(50) values are 13.47～39.12, 6.59～56.18, 372～1034 (mg·kg^(-1)), respectively.NOEC values are 5.62 ～21.41, 0.00～4.53, 133.3～327.1 mg·kg^(-1), respectively. Tangents values of regression equation of the survival of X16 strain in red soil are the maximum ones indicating that REE accumulation in red soil has stronger inhibitory effects than in other two soils. The soil order, reflecting toxic intensity of REE is as follows: red soil>yellow fluovic-aquic soil>yellow cinnamon soil.

Emerging Organic Contaminants in Chinese Surface Water:Identification of Priority Pollutants

The occurrence and impacts of emerging organic contaminants(EOCs)in the aquatic environment have gained widespread attention over the past two decades.Due to large number of potential contaminants,monitoring campaigns,treatment plants,and proposed regulations should preferentially focus on specific pollutants with the highest potential for ecological and human health effects.In the present study,a multi-criteria screening approach based on hazard and exposure potentials was developed for prioritization of 405 unregulated EOCs already present in Chinese surface water.Hazard potential,exposure potential,and risk quotients for ecological and human health effects were quantitatively analyzed and used to screen contaminants.The hazard potential was defined by contaminant persistence,bioaccumulation,ecotoxicity,and human health effects;similarly,the exposure potential was a function of contaminant concentration and detection frequency.In total,123 compounds passed the preselection process,which involved a priority index equal to the normalized hazard potential multiplied by the normalized exposure potential.Based on the prioritization scheme,11 compounds were identified as top-priority,and 37 chemicals were defined as high-priority.The results obtained by the priority index were compared with four other prioritization schemes based on exposure potential,hazard potential,or risk quotients for ecological effects or human health.The priority index effectively captured and integrated the results from the more simplistic prioritization schemes.Based on identified data gaps,four uncertainty categories were classified to recommend:①regular monitoring,derivation of environmental quality standards,and development of control strategies;②increased monitoring;③fortified hazard assessment;and④increased efforts to collect occurrence and toxicity data.Overall,20 pollutants were recommended as priority EOCs.The prioritized list of contaminants provides the necessary information for authoritative regulations to monitor,control,evaluate,and manage the risks of environmentally-relevant EOCs in Chinese surface water.

Biodegradation and ecotoxicological assessment of pectin production wastewater

The chemical composition of pectin production wastewater and its toxicity during biological treatment were investigated. Samples of wastewater from different steps of a pectin production wastewater biological treatment plant were investigated including the influent of the treatment （1）, after denitrification tank （2）, after anaerobic treatment （3） and final effuent （4）. The conventional physicochemical characteristics of samples did not indicate wastewater toxicity. However, toxicity assessments carried out on Vibrio fischeri and Scenedesmus subspicatus indicated low EC50 values. The fractionation of the samples using an XAD resin showed that the toxicity was associated with the organic matter. Wastewater apparent molecular mass distributions were 14.3, 25.0, 24.4 and 29.6 kDa for samples 1-4, respectively. Finally, characteristics of the sample by pyrolisis-gas chromatography-mass spectrometry （Py-CG-MS） demonstrated its polyphenolic nature and a 23% increase in the levels of such compounds after the first biological treatment step.

Photosynthetic Toxicity and Oxidative Damage Induced by nano-Fe3O4 on <i>Chlorella vulgaris</i>in Aquatic Environment

With the rapid development of nanotechnology and widespread use of nanoproducts, concerns have arisen regarding the ecotoxicity of these materials. In this paper, the photosynthetic toxicity and oxidative damage induced by nano Fe3O4 on a model organism, Chlorella vulgaris (C. vulgaris) in aquatic environment, were studied. The results showed that Nano-Fe3O4 was toxic to C. vulgaris and affected its content of chlorophyll a, malonaldehyde and glutathione, CO2 absorption, net photosynthetic rate, superoxide dismutase activity and inhibition of hydroxyl radical generation. At higher concentrations, compared with the control group, the toxicity of nano-Fe3O4 was significantly different. It suggested that nano-Fe3O4 is ecotoxic to C. vulgaris in aquatic environment.

Comparative Evaluation on Combined Ecotoxic Effects of Nitrofurazone and NH_(4)Cl Using Two Ciliated Protists as Model Organisms:Population Dynamics and Growth Rates

Ecotoxic effects of antibiotics or ammonium have been confirmed independently in aquatic animals,but few studies have investigated their combined effects.In aquaculture ecosystems,these pollutants frequently coexist,and often in high concentrations.In this study,the combined effects of antibiotic nitrofurazone and NH4 Cl on the population dynamics and growth rates of two species of ciliated protists,Euplotes vannus and Pseudokeronopsis rubra,were investigated.Profiles of the dose-responses were visualized,and interactions between the two pollutants were quantified by the response surface method(RSM).Results showed that 1)the dynamics of the population growth differed significantly between the testd ciliates and varied with the concentrations of the pollutants;2)the relative growth rate(RGR)of both ciliates decreased significantly with increased pollutant concentrations,while the difference in RGR between the two ciliates was not significant;3)RSM analysis demonstrated an additive effect of nitrofurazone and NH4 Cl on the RGR in both ciliates.In brief,ecotoxic effects can be caused by nitrofurazone and ammonium independently on the two test ciliates,and such effects can be strengthened when they present at the same time.These findings offer a valuable reference for evaluating combined ecotoxic effects caused by multiple pollutants in aquaculture ecosystems.

Multi-Level Approach of the Ecotoxicological Impact of a Combined Sewer Overflow on a Peri-Urban Stream

In periurban zones, urban wet weather discharges have been recognized as the most significant vector of pollution in aquatic environments. The discharge of this water without treatment into the aquatic environment could present an ecotoxicological risk for biocenosis. The aim of the INVASION project is to assess the potential ecotoxicological impact of a combined sewer overflow (CSO) on a peri-urban stream. A comparative study between upstream and downstream areas of the CSO allowed observing significant effects of this overflow on the river. We studied three layers of stream: surface water, benthic layer and hyporheic layer. To characterize the potential ecotoxicological risk of water and sediments, we used a battery of 4 bioassays: Daphnia magna, Vibrio fischeri, Brachionus calyciflorus and Heterocypris incongruens. In parallel, we measured the physico-chemical parameters: ammonium (NH4+), chromium (Cr), copper (Cu) and lead (Pb). An ecological risk is greatest for the hyporheic zone in downstream river, particularly for the solid phase. These results corroborated with the physico-chemical data obtained.

Environmental pollution with psychiatric drugs

Among all contaminants of emerging interest,drugs are the ones that give rise to the greatest concern.Any of the multiple stages of the drug's life cycle(production,consumption and waste management)is a possible entry point to the different environmental matrices.Psychiatric drugs have received special attention because of two reasons.First,their use is increasing.Second,many of them act on phylogenetically highly conserved neuroendocrine systems,so they have the potential to affect many non-target organisms.Currently,wastewater is considered the most important source of drugs to the environment.Furthermore,the currently available wastewater treatment plants are not specifically prepared to remove drugs,so they reach practically all environmental matrices,even tap water.As drugs are designed to produce pharmacological effects at low concentrations,they are capable of producing ecotoxicological effects on microorganisms,flora and fauna,even on human health.It has also been observed that certain antidepressants and antipsychotics can bioaccumulate along the food chain.Drug pollution is a complicated and diffuse problem characterized by scientific uncertainties,a large number of stakeholders with different values and interests,and enormous complexity.Possible solutions consist on acting at source,using medicines more rationally,eco-prescribing or prescribing greener drugs,designing pharmaceuticals that are more readily biodegraded,educating both health professionals and citizens,and improving coordination and collaboration between environmental and healthcare sciences.Besides,end of pipe measures like improving or developing new purification systems(biological,physical,chemical,combination)that eliminate these residues efficiently and at a sustainable cost should be a priority.Here,we describe and discuss the main aspects of drug pollution,highlighting the specific issues of psychiatric drugs.

Ecotoxicological Dynamics of the Coastal Soil Ecosystem of Oil Producing Regions of Ondo State, Nigeria

The industrial revolution marked the beginning of unprecedented anthropogenic growth and technological advancement that also inadvertently led to acute environmental degradation. This technological advancement was driven by the use fossil fuels such as crude oil. Crude oil extraction through drilling has resulted in widespread environmental pollution and deterioration of natural habitats. The Ondo State region in Nigeria presents one such expanse where large scale crude extraction operations have caused hazardous environmental pollution and toxic substance contamination. This study is a comprehensive and holistic study of the terrestrial soil ecosystem aimed towards elucidating the potential ecotoxicity that may have adversely affected the area. The results indicated that the terrestrial soil ecosystem was largely acidic (~pH6) and the organic matter content ranged from 6% to 12% indicating the soil was hydric. The results also indicated that the terrestrial soil environment was contaminated with toxic heavy metals including cadmium (Cd), chromium (Cr), lead (Pb) and arsenic (As). The toxic heavy metal concentration of the soil ecosystem was higher during the dry season. The Cr concentration in the soil samples was >3 ppm in most of the sampling sites, which exceeded WHO maximum permissible limit. Mean concentrations of the heavy metals in the soil samples in both seasons were of the order: Cr > Pb > Cd > As. The soil ecosystem was also characterized by a diverse and large population of microorganisms including bacteria like Enterobacter, Escherichia coli, and several species of fungi.

美国生态毒理数据库(ECOTOX)对中国数据库构建的启示

生态毒性数据库对于环境保护科学研究特别是环境基准研究具有非常重要的作用.目前,尚缺乏能够支撑我国环境管理工作的基础毒性数据库和平台,已成为制约我国开展环境基准、生态风险评估、环境质量评价、污染治理、毒理学等方面研究的瓶颈之一,因此亟需建立具有中国本土生物的毒性数据库和平台.ECOTOX(Ecotoxicology Knowledgebase,美国生态毒理数据库)的技术和经验对中国同类数据库构建有重要的启示作用.该研究系统综述了ECOTOX构建的核心内容:文献收集条件、数据来源、数据采集过程和数据收集元素,并与国内目前的毒性数据库和与生态调查数据密切相关的数据库进行了对比研究.ECOTOX存在数据收集内容有待增加、数据库构建方法落后、非英文文献中的毒性数据收集较少、与生态毒理学相关研究链接不够紧密的问题,同时我国毒性数据库的实用性和可靠性也有待进一步提高.从开展环境基准、生态风险评估和毒理学深入研究的角度,提出构建中国生态毒性数据库的建议,如提供完整、有效和共享的生态毒性数据资源,形成毒理数据整编标准和规范,衔接国内现有数据库,采用大数据云计算技术,注重中国本土生物和新型污染物毒性数据收集等.

Study of Behavioral Changes and Photosynthetic Activity of <i>Euglenas gracilis</i>in the Presence of Effluents from the Laboratory of Clinical Analysis

Healthcare waste has now been increasingly studied in terms of the risks or dangers that can cause the environment and human health. Waste generated in clinical analysis laboratories (CALs) deserves attention, because, due to the advent of the concept of emergent pollution, it is doubtful if the materials or reagents are disposed in the sewage by CALs, which are currently considered non-contaminated or with low risk potential, under current legislation, may actually impact the environment with actions not yet understood. This study was experimental and conducted at the Environmental Laboratory of the University of the Region of Joinville. It was used Euglena gracilis (primary trophic level) algae exposed to effluents from five sectors of a CAL: Biochemistry, Hematology, Viral Load, Tuberculosis and Immunochemistry. Samples were collected from the siphons attached to the wash sinks of the CAL materials. To verify changes in algae that denote environmental danger, behavioral changes were analyzed via NGTOX, and chlorophyll concentration was calculated by chlorophyll extraction according to Mendel’s method. Viral Load (VL) and Hematology (HT) sectors were the ones that most affected algae (Tukey test). In both sectors, there was inhibition of algae mobility and gravitaxy: in VL, due to the presence of chaotropic agents that denature organic structures;and in HT, due to the change in membrane permeability attributed to methylene blue. Also in HT, there was a search for algae adaptation by increasing the rise to the surface in order to overcome the lower luminosity due to the coloration of the environment, which also affects photosynthesis. Regarding the concentration of a-chlorophyll, the VL and HT were the most affected as well, being the first one the one that had more concentration reduction because of the presence of chaotropic agents. Considering new parameters evaluated, the discarded compounds need to be better evaluated for risk, as they affect algal photosynthesis. Procedures for removal of these compounds should be considered.

Biochar-based materials as remediation strategy in petroleum hydrocarbon-contaminated soil and water:Performances,mechanisms,and environmental impact

Petroleum contamination is considered as a major risk to the health of humans and environment.Biochars as low-cost and eco-friendly carbon materials,have been widely used for the removal of petroleum hydrocarbon in the environment.The purpose of this paper is to review the performance,mechanisms,and potential environmental toxicity of biochar,modified biochar and its integration use with other materials in petroleum contaminated soil and water.Specifically,the use of biochar in oil-contaminated water and soil as well as the factors that could influence the removal ability of biochar were systematically evaluated.In addition,the modification and integrated use of biochar for improving the removal efficiency were summarized from the aspects of sorption,biodegradation,chemical degradation,and reusability.Moreover,the functional impacts and associated ecotoxicity of pristine and modified biochars in various environments were demonstrated.Finally,some shortcoming of current approaches,and future research needs were provided for the future direction and challenges of modified biochar research.Overall,this paper gain insight into biochar application in petroleum remediation from the perspectives of performance enhancement and environmental sustainability.

The accumulation and toxicity of ZIF-8 nanoparticles in Corbicula fluminea

Metal-organic frameworks(MOFs)are promising new materials that have been intensively studied and possibly applied to various environmental remediation.However,little is known about the fate and risk of MOFs to living organisms in thewater environment.Here,the toxic effects of ZIF-8 nanoparticles(NPs)on benthic organisms were confirmed by sub-chronic toxicity experiments(7 and 14 days)using Corbicula fluminea as the model organism.With exposure doses ranging from 0 to 50 mg/L,ZIF-8 NPs induced oxidative stress behaviors similar to the hormesis effect in the tissues of C.fluminea.The oxidative stress induced by ZIF-8 NPs and the released Zn^(2+)was the crucial cause of the toxic effects.Besides,we also found that the ZIF-8 NPs and dissolved Zn^(2+)may result in different mechanisms of toxicity and accumulation depending on the dosages.The Zn^(2+)release rate of ZIF-8NPswas high at low dosages,leading to a higher proportion of Zn^(2+)taken up by C.fluminea than the particulate ZIF-8.Conversely,at high dosages,C.fluminea mainly ingested the ZIF-8 NPs and resulted in increased mortality.The results have important implications for understanding the fate and biological effects of ZIF-8 in natural aquatic environments.

Copper-uptake mediated by an ecofriendly zwitterionic ionic liquid: A new challenge for a cleaner bioeconomy

This study aims to investigate the ability of an imidazolium biobased Zwitterionic Ionic Liquids(ZILs)in enhancing the phytoavailability of copper from garden(G)and vineyard(V)soils using the model plant ryegrass.Uncontaminated and artificially contaminated CuSO_(4) soils,unamended and ZIL-amended soil modalities were designed.The copper/ZIL molar ratio(1/4)introduced was rationally established based on molecular modeling and on the maximal copper concentration in artificially contaminated soil.Higher accumulation of copper in the shoots was detected for the uncontaminated and copper contaminated ZIL amended V soils(18.9 and 23.3 mg/kg,respectively)contrary to G soils together with a ZIL concentration of around 3%(W/W)detected by LC-MS analyses.These data evidenced a Cu-accumulation improvement of 38%and 66%compared to non-amended V soils(13.6 and 13.9 mg/kg respectively).ZIL would be mainly present under Cu(II)-ZIL_(4) complexes in the shoots.The impact on the chemical composition of shoot was also studied.The results show that depending on the soils modalitity,the presence of free copper and/or ZIL led to different chemical compositions in lignin and monomeric sugar contents.In the biorefinery context,performances of enzymatic hydrolysis of shoots were also related to the presence of both ZIL and copper under free or complex forms.Ecotoxicity assessment of the vineyard soil samples indicated that the quantity of copper and ZIL remaining in the soils had no significant toxicity.ZIL amendment in a copper-contaminated soil was demonstrated as being a promising way to promote the valorization of phytoremediation plants.

The mechanism of different cyanobacterial responses to glyphosate

Glyphosate, the most extensively used herbicide globally, has raised ecotoxicological concerns because it can be transported into the aquatic environment and cause adverse effects on the aquatic system. However, the functional mechanism of glyphosate on cyanobacteria are not completely disentangled. In this study, we selected six common cyanobacteria to evaluate glyphosate effects on cyanobacterial growth in monoculture experiment. Results showed that the growth of five tested cyanobacterial species were promoted under different degrees, and only Pseudanabaena was inhibited by glyphosate. In the phylogenetic tree based on gene sequences of 5-enol-pyruvylshikimate-3-phosphate synthase(EPSPS),a target for glyphosate, we found that the position of Pseudanabaena is the closest to plant,which was sensitive to glyphosate, thereby explaining the inhibitory effect of Pseudanabaena following glyphosate exposure. The primary degraded metabolites or analogs did not induce cyanobacterial growth, laterally demonstrating that glyphosate was used as a source of phosphorus to accelerate cyanobacterial growth because phosphorus levels increased in the medium of glyphosate treatment. Overall, this study provides a better understanding of the influence of glyphosate on the composition of aquatic microbiota and explains the mechanism of cyanobacterial response to glyphosate.