Application of an inclusion complex for determination of dithianon residues in water and fruits

A 3,3′-benzidine/β-cyclodextrin fluorescence derivative (BCDFD) was prepared and characterized by means of elemental analysis and ¹H NMR. An inclusion complex was formed between BCDFD and the pesticide dithianon based on the internal cavity of β-cyclodextrin (β-CD), and the binding constant (K_S ) of the inclusion complex was investigated. The inclusion complex could be applied for the determination of dithianon residues. Based on this, a sensitive method for the determination of dithianon was established. The linear dynamic range was from 0.63 to 12.5?mg?L^?1 with a correlation coefficient of 0.9927. The limit of detection for an aqueous solution of standard and the relative standard deviation (RSD) were 10.6?µg?L^?1 and 0.76%, respectively. The proposed method has been successfully applied for the determination of dithianon residues in water and fruit samples with satisfactory results, and recoveries in the range of 96.0–108% were obtained. The method is rapid, direct, economical, and sensitive for dithianon analysis.     

Visual disturbances with cholinesterase depletion due to exposure of agricultural pesticides among farm workers

In this study, risk assessment for visual disturbances among farm workers spraying agricultural pesticides in farms have been assessed. A cross-sectional study for the assessment of visual disturbances was undertaken using questionnaire survey and clinical examination among agricultural workers exposed to pesticides. Two hundred and thirty nine pesticide sprayers participated in the study. The study was compared to 110 controls not occupationally exposed to pesticides with similar socio-economic status. The prevalence of ocular morbidity was found to be 40% among pesticide sprayers which was significantly higher (p?p?相似文献   

Human serum paraoxonase gene polymorphisms and association with chronic symptoms of pesticide toxicity in Indian farmers

The association between PON1 (serum paraoxonase) genotype and symptoms of pesticide toxicity was examined in a total of 268 farm workers in Andhra Pradesh, India. Approximately 140 of the farm workers who did not report at least two of the symptoms of chronic toxicity, such as abdominal pain, nausea, dizziness, headache, drowsiness, fatigue, tremors of fingers, numbness, or limb weakness were categorized as controls. The remaining 128 farmers showed 2 or more of the above symptoms. All the farm workers were genotyped for polymorphisms of PON1 gene at amino acid positions 55 (exon 3) and 192 (exon 6). A decrease in the percentage of high-activity genotypes at both L55M and Q192R was observed in the farm workers reporting symptoms of pesticide toxicity. When combined genotype distribution at both exons was analyzed, a marked increase in the percentage of low-activity genotypes LLQQ, LMQQ, MMQQ, and MMQR was also observed in symptomatic farmers compared to controls. Age, working years, smoking, duration of exposure, and alcoholism were not statistically significant when compared to symptoms of chronic toxicity. Our findings suggest that L55M and Q192R gene polymorphisms influence the variable susceptibility of farmers to pesticide; and thus may be considered a useful biomarker of genetic susceptibility in assessing an individual's risk of pesticide exposures.     

Determination of pesticide residues in muscle of Cyprinus carpio from River Ravi

The levels of dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), endosulfan, endosulfan sulfate, carbofuran, and cartap were determined in muscles of Cyprinus Carpio sampled from 10 different sites of River Ravi between Shahdara to Balloki Headworks to assess level of contamination of these pesticides by GC-ECD (gas chromatograph equipped with electron capture detector) method. All fish samples were found contaminated with different concentrations of DDT, DDE, endosulfan, and carbofuran. DDT and DDE concentrations were higher than maximum residue limits (MRL) in food standards, while endosulfan sulfate and cartap were not detected. These findings indicate that pesticide concentrations in fish muscles decreased in the order: DDT > DDE > carbofuran > endosulfan. Furthermore, the sampling sites after Degh fall and beyond Hudiara Nulla Fall river sampling sites were more polluted. It is proposed that constant monitoring programs are needed to assess potential exposure risks.     

Electrochemical determination of the effect of lead(II) on the photochemical degradation of the pesticide metamitron

The complexation of the pesticide Metamitron by lead(II) was investigated by polarography and stripping voltammetry. The influence of the pH on the complexation was determined and a maximum value for the conditional stability constant of the lead‐metamitron complex (logβ’ = 3.1) was obtained at pH 5.6.

An investigation into the photochemical degradation of the pesticide demonstrated that lead decreases the degradation rate of metamitron by 13% within the first 30 days, due to stabilisation by complexation.     

蜡状芽孢杆菌不同菌株降解有机磷农药的特性分析

筛选分离降解微生物解决有机磷农药残留给水体和土壤环境带来的污染问题是一项可行的生物修复技术。采用富集培养和定时取样分析有机磷农药残留的方法,分离驯化出三株能够降解有机磷农药的细菌,研究了其形态特征和生理生化特性并对其16SrDNA序列进行了分析,同时比较了三菌株对甲基对硫磷（Methyl－parathion）、毒死蜱（Chlorpyrifos）和_二唑磷（Triazophos）的降解特性。结果表明：通过富集培养得到10菌株具有降解甲基对硫磷和毒死蜱的能力,比较确定HY-1、HY-2和HY-4三菌株作为研究对象,经鉴定为蜡状芽孢杆菌（Bacilluscereus）的不同菌株,三菌株在Genbank上的登录号分别为：eu915687、eu915686和eu915688。在甲基对硫磷质量浓度为50mg·L-1时,三菌株72h的降解率分别为91．7％、87．7％与92．4％．降解率无显著性差异（P〉0．05）,当甲基对硫磷质量浓度增加到100mg·L-1时,三菌株对甲基对硫磷的降解率有所下降,其中HY-2对甲基对硫磷的降解率下降最大达23％,且和其他两菌株有显著性差异（P〈0．05o三菌株72h对100mg·L-1毒死蜱的降解率分别达到64．8％、53．7％和56．5％,在不同的毒死蜱初始质量浓度下,HY-1和HY-4两菌株对毒死蜱的降解率无显著性差异（P〉0．05）,HY-2与HY-1、HY-4两菌株有显著性差异（P〈0．05o三菌株对三唑磷的降解率均较低,其中HY-2对初始质量浓度为100mg·L-1三唑磷的降解率最高仅为20．7％,其余两菌株对三唑磷的降解率比HY-2低且无显著性差异（P〉0．05o可以得出本研究分离得到的蜡状芽孢杆菌不同菌株对有机磷农药的降解存在多态性。     

国内外农药生态风险评价暴露模拟外壳述评

在阐明农药生态风险评价暴露模拟外壳的概念和功能的基础上,介绍了美国PE〔PRZM（pesticide root zonemodel）-EXAMS（exposure analysis modeling system）〕系列外壳和EXPRESS（EXAMS-PRZM exposure simulation shell）系列外壳、欧盟SWASH（surface water scenarios help）外壳及中国PRAESS（pesticide risk assessment exposure simula-tion shell）外壳这几种已开发的农药生态风险评价暴露模拟外壳的开发目的、结构组成、输入参数、运行方式和输出结果等方面的内容,并比较分析了各暴露模拟外壳在包含模型、包含场景、模拟水体类型和主要输出结果方面的异同点,期望为我国农药生态风险评价,尤其是暴露评价研究提供有益借鉴。     

亚致死剂量溴氰菊酯对麦穗鱼谷胱甘肽S-转移酶活性的影响

本文研究了麦穗鱼Pseudorasbora parva谷胱甘肽S-转移酶的组织分布以及亚致死剂量的溴氰菊酯对其比活力和组织分布的影响.结果表明肝胰脏、肠、鳃、卵巢、肾、脾脏、鳔、肌肉谷胱甘肽S-转移酶(GSTs)活性分别占41.73%、14.31%、12.11%、10.10%、8.62%、5.23%、4.33%和3.58%.用溴氰菊酯亚致死剂量活体处理麦穗鱼120 h后,卵巢和肾GSTs的活性与对照组具有显著差异,活性提高1.85倍;肠和鳃的GSTs活性分别是对照组的1.40倍和1.44倍;对肝脏GSTs活性的诱导不显著.这表明溴氰菊酯对麦穗鱼不同组织部位诱导的时间效应和强度是不同的.     

Acute toxicity evaluation of triazophos,deltamethrin and their combination on earthworm,Eudrilus eugeniae and its impact on AChE activity

The acute toxicity of three formula grade pesticides namely, triazophos (an organophosphate, OP), deltamethrin (a pyrethroid) and combined pesticide (triazophos?+?deltamethrin) was determined in earthworm, Eudrilus eugeniae. They were exposed to different concentrations of these pesticides for 48 h by paper contact toxicity method. The LC₅₀ values for triazophos, deltamethrin and of combination were determined as 0.076, 0.031 and 0.065?μg/cm², respectively. To study the sublethal effect of these pesticides, E. eugeniae were exposed to 5% and 10% of LC₅₀ of pesticides for 48 h. Morphological alterations such as coiling, clitellar swelling, mucus release and bleeding followed by body segmentation were observed in exposed earthworm. Acetylcholinesterase (AChE) activity assayed in different regions of body segment exhibited a significant (p?<?0.05) decrease in its activity particularly in the pre-clitellar region as compared to other regions. The altered behavioural responses in pesticides exposed earthworms would have been due to decline in AChE activity of the nervous system.     

Fenton试剂强化微电解工艺预处理难降解含氰农药废水

采用Fenton试剂强化微电解反应预处理难降解含氰农药废水.实验结果表明,在总反应时间为3.0 h、反应开始时加入1 mL/L H2O2、反应1.5 h后再加入3mL/L H2O2的条件下,出水COD为372.0 mg/L,COD去除率可达80.2％,出水p(CNˉ)为2.2 mg/L,色度为20倍,BOD5/COD为0.35,可实现处理效果与经济成本的最优化.采用紫外-可见光谱分析处理后废水,发现Fenton试剂强化微电解反应可破坏部分微电解作用难以降解的有机物,但对苯环的降解能力均有限.