In vitro degradation of the herbicide atrazine by soil and wood decay fungi controlled through Elisa technique

The interaction between atrazine, a triazine herbicide, and a series of decay fungi was characterized in terms of biodegradation of the herbicide and its influence on fungal growth. The following fungi were studied: thermophilic cellulolytic (Penicillium sp. 13) and noncellulolytic (Humicola lanuginosa sp. 5 and 12) strains isolated from self‐heated plant composts, mesophilic diphenol oxidase producing strain Mycelia sterilia INBI 2–26, white‐rot fungi Cerrena maxima, Coriolopsis fulvocinerea and Coriolus hirsutus. Competitive enzyme immunoassay was elaborated for detection of atrazine in cultural liquid. During agar plate cultivation the growth of Humicola sp. 5 was promoted by atrazine whereas the growth of Humicola sp. 12 and Penicillium sp. 13 was suppressed whereas M. sterilia INBI 2–26 was not affected by the herbicide. Neither atrazine‐accelerated nor atrazine‐depressed thermophilic strains decomposed atrazine during 21‐day cultivation according to ELISA data. In contrast, white‐rot fungi Coriolus hirsutus, Coriolopsis fuhocinerea and Cerrena maxima degraded nearly 50% of the herbicide in 5‐day submerged cultivation and 80–92% of the herbicide up to the 40th day. The soil strain M. sterilia INBI 2–26 decomposed 70% of atrazine in 17‐day cultivation. The degradation level depended of the time of atrazine introduction to the growing media. The relationships between the degree of atrazine decomposition and laccase and Mn‐peroxidase production were shown.     

水土环境介质中阿特拉津修复过程研究进展

除草剂阿特拉津农用后的残留物会随地表径流或地下渗漏作用进入江河湖泊等自然水体,由于阿特拉津的环境内分泌干扰作用,其会造成水资源污染和水生态失衡。根据阿特拉津的生产和使用状况,将阿特拉津的污染对象分为土壤、市政污水、河流湖泊等地表水和地下水系统模块,分别阐述了这几种环境介质中阿特拉津的物理、化学和生物修复技术以及阿特拉津在修复过程中的变化特点,介绍了土壤在淋溶过程中阿特拉津的固定手段和今后污染水体中阿特拉津修复的研究重点。     

吸附反应时间对除草剂阿特拉津吸附行为的影响

采用批量动态实验方法,对潮土中阿特拉津吸附特征随吸附反应时间变化进行了研究。结果表明,土壤吸附的阿特拉津量随反应时间的变化符合双曲线函数关系。在50μg·L-1～2000μg·L-1浓度系列下,在48h内,土壤颗粒对阿特拉津的吸附属于快反应,土壤吸附的阿特拉津量随吸附反应时间呈指数上升,为吸附实验结束(168h)时土壤吸附阿特拉津总量的58%到90%。当吸附反应时间超过48h后,随反应时间增加,土壤吸附阿特拉津量差异变化不显著。阿特拉津在潮土颗粒和土壤溶液中的相分配可用Freundlich方程描述。吸附容量因子Kf与吸附反应时间之间有极显著的线性正关系(r2=0.9063**,p<0.0001)。无量纲的非线性因子n与吸附反应时间之间也具有显著的线性负关系(r2=0.5666*,p=0.0192)。     

图像处理在弹琴蛙(Rana adenopleura)蝌蚪生物监测研究中的应用

利用图像处理方法对不同质量浓度的阿特拉津溶液(1mg／L、5mg／L、10mg／L、15me／L)中弹琴蛙(Rana ade-nopleura)蝌蚪行为进行了图像的识别及分析．根据实验结果，利用MATLAB语言编写了弹琴蛙蝌蚪在水族缸中具体分布型判定的程序，采用了负二项分布的参数κ值来反应不同溶液中蝌蚪聚集程度的差异，并作为该指示生物监测阿特拉津水体污染情况的一个指标．结果显示，该程序可如实反映不同污染水体中蝌蚪的聚集程度：经χ^2检验各种水体中蝌蚪均符合负二项分布，同时阿特拉津溶液中蝌蚪的κ值均小于空白对照和丙酮对照，表明阿特拉津溶液的浓度和蝌蚪的聚集程度相关．图9表1参14     

Exposure of ground water to alachlor,atrazine and metolachlor in maize areas of ribatejo and oeste (Portugal)

In irrigated maize areas of an important Portuguese agricultural area, Ribatejo and Oeste Region, alachlor, atrazine and metolachlor were detected in ground water.

During the study performed from 1996 to 1998 atrazine was the herbicide that showed the highest frequency of detection. In the 177 ground water samples collected 62% were contaminated with atrazine, 30% with alachlor and 12% with metolachlor. All these herbicides were detected both in ground water for human consumption and for irrigation, in some cases above 0.1 ug/L. The maximum levels quantified were 13μg/L for alachlor, 30μg/L for atrazine and 56 μg/L for metolachlor.

Seasonal variation of residues in ground water it is also presented through several examples of studies performed during the period 1991–1999.     

Environmental fate of pesticides used in Australian viticulture V. Behaviour of atrazine in the soils of the south Australian Riverland

The transport of the s‐triazine herbicide, atrazine, through the red, calcareous earth soils of the South Australian Riverland was investigated. Small, undisturbed soil cores were extracted from the inter‐row topsoil of a vineyard adjacent to the River Murray, approximately 10 km south‐west of Overland Corner, South Australia. The vines were grown in a deep (1–4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (<2%). Atrazine concentrations in the leachate were dependent on application rate and soil type. High application rates on subsoil gave high rates of leaching for a longer time compared to the same application rate on topsoil and/or lower application rates on either topsoil or subsoil. Overall, 37–65% of the applied atrazine was detected in the leachate from subsoil cores, 14–25% in topsoil core leachates. Small amounts of atrazine (< 10% of applied dose) were found only in the top 2 cm of the core profiles. The results suggest that this herbicide is somewhat mobile in such strongly alkaline, sandy loam soils and that the irrigated soils of this region are likely to be prone to leaching of atrazine, and therefore that groundwater supplies in this area may be at risk of contamination through use of triazine herbicides.     

Unprecedented total mineralization of atrazine and cyanuric acid by anodic oxidation and electro-Fenton with a boron-doped diamond anode

This article reports the complete mineralization of atrazine. Atrazine has been the most widely used s-triazine herbicide. Atrazine occurs in natural waters and presents a potential danger for public health because atrazine is considered as an endocrine disruptor. The use of chemical, photochemical and photocatalytic advanced oxidation processes (AOPs) to decontaminate waters containing atrazine only allowed its conversion into the cyanuric acid as ultimate end products, since it cannot be completely degraded by hydroxyl radicals (^•OH) produced by these techniques. The same behavior was previously reported for anodic oxidation and electro-Fenton with Pt anode, although better performances were found using boron-doped diamond (BDD) anode but without explaining the role of generated ^•OH. Here, the oxidative action of these radicals in such electrochemical AOPs has been clarified by studying the mineralization process and decay kinetics of atrazine and cyanuric acid in separated solutions by anodic oxidation with BDD and electro-Fenton with Pt or BDD anode using an undivided cell with a carbon-felt cathode under galvanostatic conditions. Results showed that electro-Fenton with BDD anode was the more powerful treatment to degrade both compounds. Almost total mineralization, 97% total organic carbon (COT) removal, of atrazine was only feasible by this method with a faster removal of its oxidation intermediates by ^•OH formed at the BDD surface than that formed in the bulk from Fenton reaction, although the latter process caused a more rapid decay of the herbicide. Cyanuric acid was much slowly mineralized mainly with ^•OH produced at the BDD surface, and it was not degraded by electro-Fenton with Pt anode. These results highlight that electrochemical advanced oxidation processes (EAOPs) using a BDD anode are more powerful than the classical electro-Fenton process with Pt or PbO₂ anodes.     

Toxicity,degradation and analysis of the herbicide atrazine

Excessive use of pesticides and herbicides is a major environmental and health concern worldwide. Atrazine, a synthetic triazine herbicide commonly used to control grassy and broadleaf weeds in crops, is a major pollutant of soil and water ecosystems. Atrazine modifies the growth, enzymatic processes and photosynthesis in plants. Atrazine exerts mutagenicity, genotoxicity, defective cell division, erroneous lipid synthesis and hormonal imbalance in aquatic fauna and nontarget animals. It has threatened the sustainability of agricultural soils due to detrimental effects on resident soil microbial communities. The detection of atrazine in soil and reservoir sites is usually made by IR spectroscopy, ELISA, HPLC, UPLC, LC–MS and GC–MS techniques. HPLC/LC–MS and GC–MS techniques are considered the most effective tools, having detection limits up to ppb levels in different matrices. Biodegradation of atrazine by microbial species is increasingly being recognized as an eco-friendly, economically feasible and sustainable bioremediation strategy. This review presents the toxicity, analytical techniques, abiotic degradation and microbial metabolism of atrazine.     

Removal of atrazine from river waters by indigenous microorganisms

We report the first data for atrazine removal in low-turbidity freshwaters. Atrazine is a globally applied herbicide, contamination by which may lead to direct and indirect ecotoxicological impacts. Although a common contaminant of surface waters, microbial biodegradation of atrazine in this environment has been little studied, with most work focused on soils by means of selected, atrazine-degrading bacteria-enriched cultures. Here, we measured atrazine removal from river water using a batch incubation system designed to represent environmental conditions, with water from two contrasting UK rivers, the Tamar and Mersey. Atrazine and bacterial inocula prepared from the source water were added to cleaned river water for 21-day incubations that were analysed directly by electrospray ionisation-mass spectrometry. The experimental approach was validated using peptides of different molecular mass. Results show that atrazine concentrations decreased by 11% over 21 days in Tamar samples, a rural catchment with low population density, when atrazine was the only substrate added. In contrast no removal was evident in Mersey samples, an urban catchment with high population density. When a tripeptide was added as a co-substrate, atrazine removal in the Tamar water remained at 11% while that for the Mersey water increased from 0 to 37%. Although degradation of atrazine in aerobic freshwaters is predicted according to its chemical structure, our data suggest that the composition of the bacterial population determines whether removal occurs under these conditions and at these environmentally realistic concentrations.     

除草剂西玛津对非洲爪蟾生存和性腺发育的影响

为了研究三嗪类除草剂西玛津对两栖动物非洲爪蟾(Xenopus laevis)生存和性腺发育的毒性作用,并且与另一种三嗪类除草剂阿特拉津的毒性进行比较,将非洲爪蟾从46/47阶段开始暴露西玛津和阿特拉津到变态1个月后停止,再饲养2个月后将其解剖,取性腺做形态学和组织学观察.暴露期间,每天记录蝌蚪的生长发育情况和存活率.结果显示,在暴露的第1周内(蝌蚪处于46~50阶段),西玛津可导致蝌蚪死亡率明显升高,随后的时间内西玛津对非洲爪蟾的生存不再有明显影响,但却使发育阶段明显的不整齐.阿特拉津对非洲爪蟾的生存和发育则没有明显影响.西玛津和阿特拉津对非洲爪蟾性腺的总体形态和性别比没有明显影响,然而两种除草剂均在一定程度上导致了睾丸组织学的改变.西玛津可能与阿特拉津一样能够通过雌性化/去雄性化作用影响非洲爪蟾睾丸的发育.     

Removal of pesticides from water samples by adsorption with fatty acids supported on barium sulphate

Oleic or linoleic acid supported on barium sulphate was used to remove atrazine and terbuthylazine in the range of 0.1–2.0 μg/L using spiked water samples. The sorption of atrazine depends on the stirring time and the best value is 150 min. Terbuthylazine is removed well with a stirring time of 60 min and its adsorption is about 90%. Detection of the residual pesticide in treated waters, after solid phase extraction (SPE), was carried out by GC‐MS operating in selected ion monitoring (SIM) using a calibration curve by direct injection of standard solutions of herbicide.     

狼尾草根系对阿特拉津长期胁迫的氧化应激响应

通过盆栽实验研究了抗性植物狼尾草根部丙二醛(MDA)、脯氨酸(Pro)、抗坏血酸(As A)含量及超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)等氧化应激生理指标对不同浓度阿特拉津长期(48 d)胁迫的响应规律。结果表明:当阿特拉津胁迫浓度分别高于20 mg·kg~(-1)和50 mg·kg~(-1)时,狼尾草根系的MDA与Pro含量较对照组显著升高(P0.05);随着阿特拉津胁迫浓度的增加,狼尾草根部SOD和GR活性呈先升高后降低的趋势,其中当阿特拉津胁迫浓度为20 mg·kg~(-1)时,SOD和GR活性达到最大值;供试植物根系中As A含量与阿特拉津胁迫浓度呈正相关。综上,中低浓度(≤20 mg·kg~(-1))阿特拉津处理没有对狼尾草的根系产生明显的氧化胁迫效应,狼尾草根系的上述抗氧化应激生理指标对于发挥阿特拉津抗性起着重要的作用。     

Atrazine leaching into groundwater: comparison of five simulation models

Five deterministic models (BAM, GLEAMS, HYDRUS, MOUSE and TETrans) were compared to evaluate, in first order of approximation, their ability to predict different soil vulnerabilities with respect to the atrazine leachability towards shallow groundwater. Two environmental scenarios were defined on the basis of the measured groundwater contamination. The former scenario corresponded to a vulnerable sandy loam soil, the latter to a moderately vulnerable sandy loam-organic soil. The pesticide was applied on both soils for corn weed control in early June 1986, while the groundwater samplings were made in February and September 1987. The small atrazine transport into groundwater through the sandy loam-organic soil, as it was detected from the groundwater sampling in late winter, was simulated only by TET rans model. With respect to the sandy loam soil vulnerability, satisfactory simulations were performed by both TETrans and HYDRUS. The applied herbicide was leached throughout this soil towards groundwater both in February and in September 1987. Conversely, atrazine leaching simulated by GLEAMS, MOUSE and BAM compared less consistently with the measured groundwater contaminations.     

Atrazine and mancozeb induce excitotoxicity and cytotoxicity in primary cultures of mouse cerebellar cortex

This work aimed to determine the neurotoxicity of atrazine and mancozeb by high performance liquid chromatography (HPLC) evaluation of neurotransmitters, and morphologically by flow cytometry and ultrastructural analysis using transmission electron microscopy of primary cultures of mouse cerebellar cortex. The latter revealed mitochondrial damage, synaptic alterations, and neuroinflammation, while neurochemical results showed augmented release of excitatory neurotransmitters with a consequent increase in excitation/inhibition ratio of atrazine- and mancozeb-treated cultures. This study shows that atrazine and mancozeb exposure may lead to neuronal damage associated with excitotoxicity and cytotoxicity.     

Persistence of atrazine impact on aneuploidy in Pacific oysters,<Emphasis Type="Italic"> Crassostrea gigas</Emphasis>

Widespread use of the herbicide atrazine has incited much research on its toxicity in aquatic systems, where it is routinely detected due to runoff from cultivated fields. Moreover, the determination of the genotoxic effect of such pollutants in the marine environment has become a major requirement for ecosystem protection. In the Pacific oyster, Crassostrea gigas, hypodiploid aneuploid cells have regularly been reported. There is a negative correlation between this phenomenon and growth, as well as evidence for a genetic basis. A positive relationship between atrazine and aneuploidy has previously been demonstrated in C. gigas adults and juveniles. To evaluate the persistence of this impact, our study examined the offspring of the same adult population previously treated with different atrazine doses (10 µg l^–1, representing a peak value found in a polluted environment and 100 µg l^–1), and a seawater control. We observed that these offspring exhibited significantly higher aneuploidy levels when their parents had been exposed to atrazine (14.9–16.9% in comparison with the control where the levels ranged from 11.4% to 12.8%). In addition, the present study examined the aneuploidy level of a sample of juveniles, previously exposed for 3.5 months to the same doses of atrazine, then transferred to non-polluted conditions for an additional period of 2.5 months; this aneuploidy level remained significantly different between the treatments applied. These results demonstrate the persistence of an atrazine impact on Pacific oyster aneuploidy in time, within and between generations, indicating that this widely used compound may represent an important factor causing at least medium-term damage to genetic material.Communicated by S.A. Poulet, Roscoff     

Modeling pesticide fate in a small tidal estuary

The exposure analysis modeling system (EXAMS), a pesticide fate model developed by the U.S. Environmental Protection Agency, was modified to model the fate of the herbicides atrazine and metolachlor in a small tidally dominated estuary (Bath Creek) in North Carolina, USA where freshwater inflow accounts for only 3% of the total flow. The modifications simulated the changes that occur during the tidal cycle in the estuary, scenarios that are not possible with the original EXAMS model. Two models were created within EXAMS, a steady-state model and a time-variant tidally driven model. The steady-state model accounted for tidal flushing by simply altering freshwater input to yield an estuary residence time equal to that measured in Bath Creek. The tidal EXAMS model explicitly incorporated tidal flushing by modifying the EXAMS code to allow for temporal changes in estuary physical attributes (e.g., volume). The models were validated with empirical measurements of atrazine and metolachlor concentrations in the estuary shortly after herbicide application in nearby fields and immediately following a rain event. Both models provided excellent agreement with measured concentrations. The steady-state EXAMS model accurately predicted atrazine concentrations in the middle of the estuary over the first 3 days and under-predicted metolachlor by a factor of 2–3. The time-variant, tidally driven EXAMS model accurately predicted the rise and plateau of both herbicides over the 6-day measurement period. We have demonstrated the ability of these modified EXAMS models to be useful in predicting pesticide fate and exposure in small tidal estuaries. This is a significant improvement and expansion of the application of EXAMS, and given the wide use of EXAMS for surface water quality modeling by both researchers and regulators and the ability of EXAMS to interface with terrestrial models (e.g., pesticide root zone model) and bioaccumulation models, we now have an easily-accessible and widely accepted means of modeling chemical fate in estuaries.     

基于光谱学和电化学方法的莠去津毒理作用评价

为探索莠去津对DNA的损伤及其毒性作用机制,采用紫外吸收光谱法、荧光光谱法以及电化学方法研究了莠去津与鲱鱼精DNA的相互作用,探讨了二者形成DNA加合物的作用方式.结果表明,莠去津与鲱鱼精DNA作用后,莠去津的紫外光谱呈现减色效应,并有轻微红移现象,而其荧光光谱强度明显增强;循环伏安法显示莠去津与DNA作用能引起莠去津还原电位正移,峰电流减小.以上实验结果表明,莠去津平面分子能够嵌插到DNA双螺旋链中,形成较稳定的加合物.采用电化学方法测得莠去津与鲱鱼精DNA的结合比为1:1,结合常数为1.2×105.该研究为莠去津毒理作用评价提供了一种简便的方法。     

低浓度阿特拉津长期暴露对鲫鱼DNA的影响

运用随机扩增多态性DNA(RAPD)技术在分子生物学水平上评价了低浓度阿特拉津长期暴露对鲫鱼DNA的影响.结果表明:0.006mg·L-1以上浓度(试验浓度系列为0.006、0.023、0.094、0.375、1.5、3mg·L-1)的阿特拉津持续暴露60d均会对鲫鱼的DNA产生影响;经筛选,确定有34条引物能够扩增出鲫鱼基因组DNA,其中有8条引物能检测出阿特拉津对鲫鱼基因组DNA影响的差异:各浓度组鲫鱼DNA的RAPD扩增产物条带均出现不同程度缺失;在较低浓度长期暴露下阿特拉津对鲫鱼基因组DNA的损伤无明显的剂量-效应关系,阿特拉津毒性在0.375mg·L-1时突然增强,但这一趋势并未向更高浓度组延续(1.5mg·L-1组表现出的毒性弱于0.375mg·L-1组和3mg·L-1组).     

阿特拉津在天然水体沉积物中的吸附行为

本文研究了阿特拉津在几种水体沉积物中的吸附、解吸规律,并进一步探讨了沉积物浓度、pH值和离子强度对其吸附行为的影响．结果表明,不同沉积物对阿特拉津的吸附程度由沉积物本身的总有机碳、粘土矿物、阳离子交换容量、比表面积以及铁锰氧化物等理化特性综合作用的结果,有机碳不是影响阿特拉津吸附的唯一重要因素．连续吸附实验结果指出,化合物的起始浓度愈大,吸附时间愈长,阿特拉津的最大吸附容量也愈大,且在解吸过程中表现出一定的滞后性(即不可逆吸附)．沉积物浓度与其吸附量呈负相关;溶液的pH值增大,沉积物对阿特拉津吸附能力减弱;离子强度愈大,沉积物对阿特拉津吸附能力愈强．     

Climate Change,Multiple Stressors,and the Decline of Ectotherms

Climate change is believed to be causing declines of ectothermic vertebrates, but there is little evidence that climatic conditions associated with declines have exceeded critical (i.e., acutely lethal) maxima or minima, and most relevant studies are correlative, anecdotal, or short‐term (hours). We conducted an 11‐week factorial experiment to examine the effects of temperature (22 °C or 27 °C), moisture (wet or dry), and atrazine (an herbicide; 0, 4, 40, 400 μg/L exposure as embryos and larvae) on the survival, growth, behavior, and foraging rates of postmetamorphic streamside salamanders (Ambystoma barbouri), a species of conservation concern. The tested climatic conditions were between the critical maxima and minima of streamside salamanders; thus, this experiment quantified the long‐term effects of climate change within the noncritical range of this species. Despite a suite of behavioral adaptations to warm and dry conditions (e.g., burrowing, refuge use, huddling with conspecifics, and a reduction in activity), streamside salamanders exhibited significant loss of mass and significant mortality in all but the cool and moist conditions, which were closest to the climatic conditions in which they are most active in nature. A temperature of 27 °C represented a greater mortality risk than dry conditions; death occurred rapidly at this temperature and more gradually under cool and dry conditions. Foraging decreased under dry conditions, which suggests there were opportunity costs to water conservation. Exposure to the herbicide atrazine additively decreased water‐conserving behaviors, foraging efficiency, mass, and time to death. Hence, the hypothesis that moderate climate change can cause population declines is even more plausible under scenarios with multiple stressors. These results suggest that climate change within the noncritical range of species and pollution may reduce individual performance by altering metabolic demands, hydration, and foraging effort and may facilitate population declines of amphibians and perhaps other ectothermic vertebrates. Cambio Climático, Estresantes Múltiples y la Declinación de Ectotermos