Impact of Long-Term Atrazine Use on Groundwater Safety in Jilin Province, China

The long-lasting application of representative herbicide atrazine （ATR） has given rise to the accumulation of its residues in the groundwater. To investigate the impact of long-term ATR use on groundwater safety, the residues of ATR and its metabolites, desethylatrazine （DEA）, deisopropylatrazine （DIA） and hydroxyatrazine （HA） were monitored in groundwater and top soil at the major corn growing region of Qian＇an and Gongzhuling in Jilin Province, China. The residues of the target compounds were analyzed by UPLC-MS/MS. The limits of detection （LODs） ofATR, DEA, DIA, and HA were 0.5, 0.5, 5, and 0.5 ng L-1 in groundwater and 0.33, 0.33, 3.3, and 0.33 μg kg-1 in soil. The target compounds were found in 94% of groundwater samples and 100% of soil samples. The compounds detected most frequently in groundwater were ATR （89%）, DEA （64%） and HA （17%）, whereas in soil were ATR （97%）, DEA （36%） and HA （97%）. DIA was not detected in any determined groundwater and soil sample. Average residues were 106.8 ng L-1 for ATR, 0.9 ng L-1 for DEA and 0.3 ng L-1 for HA in groundwater, whereas 11.1 μg kg-1 for ATR, 0.4 μg kg-1 for DEA and 7.8 μg kg-1 for HA in soil. ATR residues detected in groundwater samples were below standards for drinking water quality （GB5749-2006, 2 μg L-1）, while the total residues of ATR and its chloro-s-triazine metabolites （DEA and DIA） were below current WHO （World Health Organization） guideline value （GV, 0.1 mg L-1）. In addition, concentrations of HA in groundwater were determined below current WHO GV （0.2 mg L-1）. The results indicated that ATR is safe to be used in Jilin Province under the current application scheme. However, total residues of ATR and DEA were detected in nearly all wells, thus, it is necessary to pay attention on groundwater monitoring for ATR and its metabolites.

Plantain-based diet modulates atrazine-induced testicular toxicities in rats

Objective:To assess the potential of plantain-based diet in modulating testicular toxicities in rats exposed to atrazine.Methods:The plantain-based diet at 50%,25% and 12.5% were prepared from the basal diet by substituting the corn starch with plantain fruit pulp flour at different percentages.Wistar rats were fed plantain-based diet in varying concentrations ranging from 12.5% to 50% of the basal diet for 21 days before or after atrazine treatment in a two-phase experiment:preventive and therapeutic phases.The therapeutic model(n=35)had seven groups with 5 rats each,including the control,atrazine,atrazine recovery,atrazine plus plantain-based diet 50%,25%,12.5%,and atrazine plus quercetin groups.The preventive model(n=30)had six groups of 5 rats,consisting of the control,atrazine,50%,25%,12.5% plantain-based diet plus atrazine,and quercetin plus atrazine groups.Gonadal hormones(testosterone,luteinizing hormone and follicle-stimulating hormone),sperm parameters(sperm motility,viability,morphology and concentration),and testicular function indices(protein,cholesterol,glycogen,acid phosphatase,alkaline phosphatase and lactate dehydrogenase)were measured.Results:The gonadal hormones,sperm characteristics,and testicular function indices of the rat testis decreased significantly in the atrazine group alongside degeneration of the histoarchitecture.However,plantain-based diet restored the gonadal hormone concentrations,semen parameters,and testicular function indices in both the preventive and therapeutic models.Conclusions:Treatment with plantain-based diet protects against rat testicular toxicity caused by atrazine via the modulation of gonadal hormones,sperm quality,testicular function index as well as histoarchitecture of rat testes.

Effects of Atrazine Stress on the Growth of Pennisetum hydridum

[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress （20, 50, 100, 200, 500 mg/kg） on plant height, biomass, root-shoot ratio and chlorophyll content of P. hydridum. [Results] Low level of atrazine stress （20 and 50 mg/kg） showed no significant effects on plant height and biomass of P. hydridum. Moderate level of atrazine stress （100 and 200 mg/kg） did not show significant effect on plant height, but did on the biomass of P. hydridum. Biomass of P. hydridum stressed by 100 and 200 mg/kg of atrazine was decreased by 34.1% and 36.4% compared with control, respectively. High level of atrazine stress （500 mg/kg） brought significant decrease in plant height（by 40.6%） and biomass（20.0%） of P. hydridum. All levels of atrazine stress showed no significant effects on root-shoot ratio and chlorophyll content of P. hydridum. [Conclusion] Pennisetum hydridum has strong tolerance to atrazine stress.

反相高效液相色谱与毛细管气相色谱联用测定水中的Atrazine

Atrazine(2-氯-4-乙胺基-6-异丙胺基-1,3,5-三嗪)是一种广泛使用的除莠剂。西欧许多国家对其在饮用水中的含量法定检测限必须小于0.1ppb。且前通常是采用液液或液固萃取富集。

Microbial Community Characteristics in the Rhizosphere of Atrazine-contaminated Soil by Dendroremediation of Poplar

The change of microbial community characteristics in the different rhizo- sphere zones of hybrid poplar （Populusdeltoidsxnigra, DN34） under atrazine stress were investigated by rhizo-boxes and Biolog system in a greenhouse experiment, with sublimed sulfur and calcium hydroxide as soil pH regulators. Data from the measurement by the Biolog ECO plate demonstrated that the value of average well color development （AWCD） and the carbon source utilization of soil microorganisms in the treatments with pH regulators were promoter than CK during the initial 30 days; while the results from the 90 days indicated that the activity and the carbon source utilization of soil microbes in acid regulator treatment began to fall down, even lower than that of poplar implant treatment, then the alkaline treatment could still stimulate and promote the activity and the carbon source utilization ability of soil microbes. Overall, the activity and community structure of soil microbes in rhizo- sphere zones of atrazine-contaminated soil did not show steady regularity during the phytoremediation process by using hybrid poplars. For the reason that the Biolog E- CO plate, which only had 31 kinds of carbon sources, could not really indicate the detail information about the function diversity of community structure of soil mi- crobes. So it＇s essential for us to take more sophisticated analysis tools for further study.

Isolation and characterization of atrazine-degrading Arthrobacter sp. AD26 and use of this strain in bioremediation of contaminated soil

A bacterial strain (AD26) capable of utilizing atrazine as a sole nitrogen source for growth was isolated from an industrial wastewater sample by enrichment culture. The 16S rRNA gene sequencing identified AD26 as an Arthrobacter sp. PCR assays indicated that AD26 contained atrazine-degrading genes trzN and atzBC. The trzN gene of AD26 only differs from the trzN of Arthrobacter aurescens TC1 by one base (A→T at 907) and one amino acid (Met→Leu at 303). The specific activity of trzN of AD26 in crude cell ext...

Sorption of dissolved organic matter and its effects on the atrazine sorption on soils

The dissolved organic matter(DOM), water soluble organic matter derived from sewage sludge was separated into hydrophobic fraction(Ho) and hydrophilic fraction(Hi). The sorption of DOM and its fractions on soils and the effects of DOM sorption on a nonionic pesticide(atrazine(2-chloro-4-ethylamino-6-isopropylamino-1,3,5-trazine)) distribution between soil and water were investigated using a batch equilibrium technique. The total DOM sorption on soils described by the Langmuir equation reached saturation as the DOM concentration increased. The sorption of Ho fit the Freundlich model. In contrast, a negative retention evidently occurred as adding Hi at higher level in tested soils. The sorption of Ho dominated the total DOM sorption and the release of soil organic matter(SOM). Effects of DOM on the atrazine sorption by soils were DOM-concentration dependent and dominated by the interaction of atrazine, DOM, and soil solids. Generally, the presence of DOM with lower concentration promoted atrazine sorption on soils, namely the apparent partitioning constant(K*_d) for atrazine sorption in the presence of DOM was larger than the distribution constant(K_d) without DOM; whereas the presence of DOM with higher concentration inhibited atrazine sorption(i.e., K*_d<K_d). The overall effects of DOM on atrazine sorption in soils might be related to the DOM sorption and the release of soil intrinsic organic matter into aqueous solution. The sorption of Ho on soils promoted the atrazine sorption on soil, while the release of SOM by Hi and the competitive sorption between Hi and atrazine on soil surface led to a decrease of atrazine sorption. Information provided in this work may contribute to a better understanding of the DOM sorption and its impacts on the contaminant soil-water distribution.

Toxic Effects of Atrazine on Reproductive System of Male Rats

Objective This study was designed to evaluate the toxic effects of Atrazine （ATZ） on the reproductive system of male rats. 〈br〉 Methods Male Sprague-Dawley rats were exposed to ATZ by gavage at dosages of 0, 38.5, 77, and 154 mg/kg bw/day for 30 d. The toxic effects of ATZ to rats were assessed through histopathologcal observation, spermatozoa quality evaluation, testicular marker enzyme indicators, antioxidant capacity and reproductive hormone levels. Results Significant adverse effects on reproductive system were observed in rats exposed to ATZ at different dosages compared with 0 mg/kg group, including an irregular and disordered arrangement of the seminiferous epithelium in 154 mg/kg group;a decreased spermatozoa number and an increased spermatozoa abnormality rate in 77 and 154 mg/kg groups;decreased levels of acid phosphatase （ACP）, alkaline phosphatase （AKP）, lactic dehydrogenase （LDH）, and succinate dehydrogenase （SDH） with the increasing of ATZ concentration; a decreased level of total antioxidant capacity （TAC） in a dose-dependent manner, and a decreased reduced glutathione （GSH） level and an increased malondialdehyde （MDA） content in 154 mg/kg group;and decreased serum levels of testosterone （T） and inhibin-B （INH-B） and an increased serum level of follicle stimulating hormone （FSH） in 77 and 154 mg/kg groups, and an increased serum level of luteinizing hormone （LH） in 154 mg/kg group. Conclusion These results suggested that relatively high doses of ATZ could exert reproductive toxicity of male rats.

Rapid treatment of atrazine-contaminated water by nickel/iron bimetallic system

The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic conditions. The dechlorination reaction approximately followed the first-order kinetics under the experimental conditions(nickel/iron:1.0 g/250 ml;C atrazine=20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni:Fe within 2.95%. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518(R=0.9927), 0.06212(R=0.9846) and 0.00131 min -1(R=0.9565) at pH=2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atrazine concentration.

Effect of Interaction of Non-residual Fractions on Adsorption of Atrazine onto Surficial Sediments and Natural Surface Coating Samples

To quantify the effect of the interaction of non-residual fractions[Fe oxides（Fe）, Mn oxide（Mn）, organic materials（OMs）] in the surficial sediments and the natural surface coating samples on the adsorption of atrazine（AT）, an AT multiple regression adsorption model（AT-MRAM） was developed. The AT-MRAM improves upon the previous AT additional adsorption model（AT-AAM） with superior goodness-of-fit test（adjusted R2=ca.1.000）, F-test and t-test（P〈0.01）, and reveals the effect of the interaction among the components in the surficial sediments（SSs） and na- tural surface coatings samples（NSCSs） on the adsorption of AT, which was neglected by the AT-AAM. Meanwhile, the AT-MRAM was also verified through adsorption experiments of AT and the relative deviation between predicted maximum adsorption of AT and the experimental one is less than 15%. The resulted information shows that Mn is prone to interact with other non-residual components, the total maximum adsorption of AT is inversly proportional to the level of Mn, and Fe and OMs facilitate the adsorption of AT. The results also indicate that the adsorption of AT is not only dominated by Fe, OMs, Fe/OMs, but also restrained by Fe/Mn, Fe/Mn/OMs, with lesser roles attributed to Mn, and the estimated AT distributions among the components do not agree with that previously predicted by the AT-AAM, especially with the relative contribution of Mn to the adsorption of AT, revealing significant contribution of the interactions among non-residual components in controlling the behavior of AT in aquatic environments.

Measurement of Atrazine Adsorption onto Surficial Sediments(Natural Surface Coatings)——New Evidence for the Importance of Fe Oxides

To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting（NLSF） to estimate the relative contribution of the components. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, before and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs（NSCSs） facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs（NSCSs） particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar basis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in controlling the environmental behavior of AT in an aquatic environment.

Synergetic and Antagonistic Effects of Cadmium on Adsorption of Atrazine on Surficial Sediments

Co-contamination of atrazine（AT） and cadmium（Cd） on the surficial sediments（SSs） and natural suface coating samples（NSCSs） was investigated via thermodynamic adsorption experiments. The results show that surface coatings have a stronger ability to adsorb AT owing to their higher active components compared with surficial sediments. Synergetic and antagonistic effects of Cd on the adsorption of AT were observed. Cd at a lower concentration（≤4.0 mg/L） in the solid/liquid phase enhanced AT adsorption onto the surficial sediments（surface coatings）, while the adsorption of AT would be inhibited at a Cd concentration of more than 8.0 mg/L： AT coordinates strongly to Cd, and AT-Cd complexes seem to be more strongly adsorbed on sediments than AT alone, and at the adsorption of AT can take place on the sites where Cd has been previously adsorbed and Cd acts as a bridge for the interaction be- tween sediments and AT. With the increase of Cd concentration, the superfluous Cd may hold much more adsorption sites and thus inhibits the adsorption of AT. Meanwhile, the effects of co-existed AT on Cd adsorption on SSs（NSCSs） were insignificant since Cd has a stronger competitive ability to be absorbed on SSs（NSCSs）. The present study could be useful in predicting interactions of the metal ions with herbicides and potentially aid the design of remediation strategies for contaminated sediments and groundwater.

Degradation of Herbicides Atrazine and Bentazone Applied Alone and in Combination in Soils

The application of a mixture of bentazone(3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide)and atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine)is a practical approach to enhance the herbicidal effect.Labo- ratory incubation experiments were performed to study the degradation of bentazone and atrazine applied in combination and individually in maize rhizosphere and non-rhizosphere soils.After a lag phase,the degradation of each individual herbicide in the non-autoclaved soil could be adequately described using a first-order kinetic equation.During a 30-d in- cubation,in the autoclaved rhizosphere soil,bentazone and atrazine did not noticeably degrade,but in the non-autoclaved soil,they rapidly degraded in both non-rhizosphere and rhizosphere soils with half-lives of 19.9 and 20.2 d for bentazone and 29.1 and 25.7 d for atrazine,respectively.The rhizosphere effect significantly enhanced the degradation of atrazine, but had no significant effect on bentazone.These results indicated that biological degradation accounted for the degrada- tion of both herbicides in the soil.When compared with the degradation of the herbicide applied alone,the degradation rates of the herbicides applied in combination in the soils were lower and the lag phase increased.With the addition of a surfactant,Tween-20,a reduced lag phase of degradation was observed for both herbicides applied in combination. The degradation rate of bentazone accelerated,whereas that of atrazine remained nearly unchanged.Thus,when these two herbicides were used simultaneously,their persistence in the soil was generally prolonged,and the environmental contamination potential increased.

Theoretical Researches on the Recognizing Characteristics of Atrazine Imprinted Polymers with Different Functional Monomers

As a widely used herbicide, the threat of atrazine to both environment and health of people has become the focus. Therefore, the research and analysis of atrazine are getting more important. In this work, the MIT was used to detect atrazine theoretically. Atrazine was taken as a template molecule. MAA, MMA and TFMAA were taken as the functional monomers, respectively. The geometry optimization, the nature of hydrogen bonds, the NBO charge, and the binding energies of the imprinted molecule with the functional monomers were investigated at the B3LYP/6-31g（d,p） level. Results indicated that atrazine had the strongest interaction with TFMAA. When the ratio of atrazine and TFMAA was 1：6, the amount of H-bond formed from atrazine and TFMAA was the largest. Moreover, TFMAA owned the largest binding energy with atrazine while MMA owned the smallest. The study is helpful to interpret experiment phenomena of molecular imprinting and select better functional monomers.

Modeling atrazine transport in soil columns with HYDRUS-1D

Both physical and chemical processes affect the fate and transport of herbicides. It is useful to simulate these processes with computer programs to predict solute movement. Simulations were run with HYDRUS- 1 D to identify the sorption and degradation parameters of atrazine through calibration from the breakthrough curves （BTCs）. Data from undisturbed and disturbed soil column experiments were compared and analyzed using the dual-porosity model. The study results show that the values of dispersivity are slightly lower in disturbed columns, suggesting that the more heterogeneous the structure is, the higher the dispersivity. Sorption parameters also show slight variability, which is attributed to the differences in soil properties, experimental conditions and methods, or other ecological factors. For both of the columns, the degradation rates were similar. Potassium bromide was used as a conservative non-reactive tracer to characterize the water movement in columns. Atrazine BTCs exhibited significant tailing and asymmetry, indicating non-equilibrium sorption during solute transport. The dual-porosity model was verified to best fit the BTCs of the column experiments. Greater or lesser concentration of atrazine spreading to the bottom of the columns indicated risk of groundwater contamination. Overall, HYDRUS-1D successfully simulated the atrazine transport in soil columns.

Detection of Atrazine Residue in Food Samples by a Monoclonal Antibody-based Enzyme-linked Immunosorbent Assay

Atrazine（AT,2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine）has been detected in ground water in several areas of the United States for many years,as well as in China,wherein the growth rate of its gross

Atrazine Adsorption Behavior on a Fluvo-Aquic Soil as Influenced by Contact Periods

A batch experiment was performed to investigate nonequilibrium adsorption behavior of atrazine （2-chloro-4-ethylamino-6-isopropylamlno-1,3,5-triazlne） on a fluvo-aquic soil. The amount of atrazine sorbed increased with increasing adsorption contact periods. For a range of initial atrazlne concentrations, the percentage of atrazine sorbed within 24 h ranged from 24% to 77% of the observed total amount sorbed for the longest contact period; when adsorption contact periods were more than 72 h, the deviations in curves fitted using a nonlinear Freundllch equation gradually became less. The opposite trend was observed for the atrazine concentrations in solution. The effect of adsorption contact periods on atrazine adsorption behavior was evaluated by interpreting the temporal variations in linear and nonlinear Freundlich equation parameters obtained from the phase-distribution relationships. As the adsorption contact period increased, the nonlinear Freundlich capacity coefficient kf showed a significant linear increase （r^2 = 0.9063, P 〈 0.001）. However, a significant negative linear correlation was observed for the nonlinear coefficient n, a dimensionless parameter （r^2 = 0.5666, P 〈 0.05）. Furthermore, the linear distribution coefficient kd ranged from 0.38 to 1.44 and exhibited a significant linear correlation to the adsorption contact period （r^2 = 0.72, P 〈 0.01）. The parameters kf and n obtained from a time-dependent isotherm rather than the distribution coefficient kd estimated using the linear Freundlich equation were more appropriate to predict the herbicide residue in the field and thus more meaningful for environmental assessment.

Agrobacterium-mediated Transformation of Rice (Oryza sativa L.) with Atrazine Chlorohydrolase Gene (atzA)

Atrazine chlorohydrolase gene (atzA) was cloned from Arthrobacter sp. AD1. A plant expression plasmid was constructed under the control of CaMV35s promoter and was used in rice transformation. The target gene was successfully introduced into mature embryos of a japonica rice cultivar Jindao 107 by Agrobacterium- mediated transformation and hundreds of transgenic plants were obtained. The exogenous atzA gene in the transgenic plants that expressed atrazine resistance was confirmed by Southern blot hybridization. The resistance experiments by spraying transgenic rice plants with 0.133% atrazine shown that most of the transgenic rice plants exhibited the resistance to herbicide atrazine. The segregation of exogenous atzA gene in T1 progeny corresponded to the Mendelian ratio.

Degradation of atrazine and changes in soil biological indices throughout dendroremediation using poplars

Dendroremediation,a novel strategy for cleaning up contaminants from the environment by using special woody plant species and microbes,is a popular phytoremediation approach.It is a cost-effective and environmentally friendly method that is being increasingly adopted.Poplar species(Populus L.)have been suggested for use in remediation because of their characteristics of high biomass production,fast growth,and potential for removing pollutants.Our environment is often contaminated by toxic substances produced by human activities,and remediation of contamination is therefore a global issue.Atrazine is one of the most widely used herbicides in China.In the present study,‘I-69/55’poplar(P.deltoides cv.‘I-69/55’)and hybrid poplar(Populus deltoides×nigra,DN34)grown in pots were assayed for their ability to remediate atrazine-contaminated soils.The degradation dynamics of atrazine were assessed with a high-performance liquid chromatography system using materials from a greenhouse with different rhizosphere environments.We studied the dynamic variation in microbes and microbial biomass carbon to elucidate the rhizosphere effects and mechanism of remediation of atrazine-contaminated soil by poplar.Our four treatments included a control with uncontaminated soil without a tree,atrazine pollution without a tree,atrazine pollution with‘I-69/55’poplar,and atrazine pollution with hybrid poplar.Hybrid poplar showed potential for remediation of atrazine-contaminated soil,and the degradation of atrazine in the rhizosphere was faster than that in non-rhizosphere soil.Atrazine significantly inhibited bacteria growth in nonrhizosphere soil.The high concentration of bacteria in the hybrid poplar rhizosphere might be key to atrazine degradation.Trends of change among fungi and actinomyces did not correspond to trends in atrazine degradation throughout the trial period.Further research is needed to predict the effects of atrazine on cultivable microorganisms in various soils.Atrazine had significant inhibitory effects on microbial biomass carbon in non-rhizosphere soil,and the rhizosphere environment of poplars enhanced the recovery of microbial biomass carbon.The potential for hybrid poplar as a dendroremediation material needs further study.

Enhanced atrazine adsorption from aqueous solution using chitosan-modified sepiolite

A novel clay mineral biocomposite, chitosan-modified sepiolite(CMSEP), was prepared and used as adsorbent to remove atrazine from water. The adsorption behaviors including thermodynamic and kinetic parameters, effect factors and mechanisms of atrazine adsorption on CMSEP were studied. The results show that the adsorption capacity of atrazine on CMSEP increases with increasing temperature. Protonation of chitosan in biocomposite can improve adsorption ability of the composite to a certain extent. The parameters ΔGΘ, ΔHΘ and ΔSΘ are-1.48--2.69 k J/mol, 7.54 k J/mol and 30.28 J/mol, respectively. Langmuir isotherm is proved to describe the adsorption data better than other isotherms with a maximum adsorption capacity of 17.92 mg/g, suggesting that the adsorption process is homogeneous. Pseudo-second-order kinetic model can fit the adsorption kinetic processes well although intraparticle diffusion can not be discarded. Briefly, CMSEP has potential value in the removal of atrazine from water and wastewater.