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.

节杆菌和腐熟鸡粪混施对Atrazine污染土壤特性影响

为明确节杆菌菌株MSD6与腐熟鸡粪混用修复阿特拉津污染土壤的潜力。采用模拟阿特拉津污染土壤,设5个处理:CK1,空白对照,无添加林地土;CK2,药剂对照,仅添加阿特拉津;T1,阿特拉津+菌株MSD6(5×10^(8)CFU·kg^(-1));T2,阿特拉津+腐熟鸡粪50 g;T3,阿特拉津+菌株MSD6(5×10^(8)CFU·kg^(-1))+腐熟鸡粪50 g。结果表明,菌株MSD6和腐熟鸡粪混施能显著降低土壤阿特拉津含量,并能较好恢复阿特拉津引起的土壤微生物量碳和土壤酶活性的降低。培养40 d后,T3处理的阿特拉津降解率为92.8%,土壤微生物量碳较CK2升高206.8%。T3处理的土壤过氧化氢酶、碱性磷酸酶、蔗糖酶和脲酶活性显著高于CK2处理。综上所述,节杆菌菌株MSD6与腐熟鸡粪混用能有效地改善阿特拉津污染土壤的生物学特性。

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.

除草剂莠去津(atrazine)在土壤-水环境中的吸附及其机理

为指导农药的使用 ,避免对后茬作物的影响 ,优化农药的施用量、减少环境污染 ,研究了土壤、腐殖酸、粘土矿对莠去津的吸附及其机理 .结果表明 :吸附强弱与土壤理化特性密切相关 ,Feundlich常数 Kaf与 OM%有较好的相关性 ( r=0 .975) .腐殖酸对其的吸附起决定作用而粘土矿对其吸附作用并不强 .莠去津在土壤中的吸附可能有氢键、范德华力等作用 .

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.

除草剂阿特拉津(Atrazine)溶液中弹琴蛙蝌蚪(Rana adenopleura)的行为模式

研究了不同条件下阿特拉津溶液中 (ρ1～ 4/mgL-1:5 ,10 ,15 ,2 0 )弹琴蛙 (Ranaadenopleura)蝌蚪的行为 ,运用方差分析 (ANOVA)检验了蝌蚪在不同浓度的阿特拉津、时间段、pH值、溶氧量等条件下的行为差异性 .根据实验结果 ,确立了正常及异常行为模式 .结果表明 :在水温 (15 .0± 0 .5 )℃的条件下 ,弹琴蛙蝌蚪异常行为的出现主要与阿特拉津的浓度有关 ,同时与实验时间的长短也有一定的关系 ,而与 pH值、溶氧量关系不大 .实验组与对照组相比 ,蝌蚪出现异常行为的频次差异极显著 (P <0 .0 1) ;其中在实验组中 ,蝌蚪在 5mg/L的阿特拉津溶液中与 10mg/L、15mg/L、2 0mg/L中出现异常行为的频次差异极显著 (P <0 .0 1) ,而在 10mg/L、15mg/L、2 0mg/L阿特拉津溶液中出现异常行为的频次差异不显著 (P >0 .0 5 ) ,相关性分析表明 ,蝌蚪异常行为的出现与阿特拉津的浓度没有剂量反应关系 (r2 =0 .4 94 ) ;在对照组中 ,0 .5mL/L丙酮对照和空白对照中蝌蚪出现异常行为的频次差异不显著 (P >0 .0 5 ) .图 3表 2参

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.

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.

东辽河流域地表水体中Atrazine的环境特征

在野外踏勘调查与室内分析的基础上,以GIS技术为关键数据处理平台,系统剖析了东辽河流域地表水体中莠去津(Atrazine)的含量和富集特征的时空分异;并对其影响因素进行了分析.结果表明,东辽河流域旱田分布区和非旱田分布区内地表水中Atrazine的平均含量分别为9 .71 μg·L-1 和8 . 85. 4 μg·L-1 ,在干流下游形成了分布的高值区;7月份是流域地表水中Atrazine含量最高的时期,最大值可达1 8 . 93μg·L-1 .水体中Atrazine的空间分布进一步表明,在东辽河流域旱田施放的Atrazine已经危及到整个流域的地表水水质,将对流域的生态环境产生严重的影响.相对于植物来说,东辽河流域Atrazine在地表水中富集的归一化指数为0 . 6 0 5～1 .75 0 ;从空间分异上看,干流右侧流域形成了连片的高值区,而左侧形成了连片分布的低值区,且在下游形成富集程度的集中高值区.地表水中Atrazine相对于土壤的富集特征的空间分异与相对与植物的富集特征相类似,但其高值区和低值区都是散斑状分布.从土壤类型对水体中Atrazine含量的影响看,低位泥炭土的综合表征指数较高,泥炭沼泽土和水稻土的综合表征指数较小;从景观格局对地表水中Atrazine含量的影响看,随着斑块间相互作用能力的增强,水中Atrazine的综合表征指数逐渐升高.在一定的范?

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.

光系统Ⅱ抑制型除草剂Atrazine诱导小麦幼苗叶绿体蛋白质组变化分析

为了研究除草剂作用机理,用光系统Ⅱ抑制型除草剂阿特拉津(Atrazine)处理小麦幼苗,用2-DE技术和生物质谱方法,分析了叶绿体蛋白质组的变化。结果发现,在10mg·L-1浓度处理时,有7个叶绿体蛋白质斑点(斑点1,50kDa/PI8.1;斑点2,41kDa/PI8.4;斑点3,41kDa/PI7.6;斑点4,23kDa/PI7.1;斑点5,31kDa/PI5.0;斑点6,35kDa/PI8.9;斑点7,14kDa/PI8.1)丢失。对7个发生变化的斑点利用MALDI-MS方法,于NCBI进行数据查询,其中,有6个叶绿体蛋白质归属得到鉴别,它们是Calvin循环中,固定CO2的RuBPcase的激活酶(2个同工体和1个β型前体),在H2O氧化裂解中起重要作用的23kDa氧释放蛋白(psbp protein),在能量转贮中起重要作用的3-磷酸甘油酸激酶和催化HCO3--CO2水合作用可逆反应的碳酸酐酶。研究表明,叶绿体蛋白质组中丢失的6个蛋白质是Atrazine处理的相关蛋白。