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。     

Characterization of chlorine dioxide as disinfectant for the removal of low concentration microcystins

Microcystins, which represents one kind of cancerogenic organic compounds, is abundant in eutrophication water. The effects of reaction factors on chlorine dioxide (ClO₂) for removal of low-concentration Microcystin-LR, Microcystin-RR, and Microcystin-YR in water as well as the reaction mechanisms was investigated by using enzyme-linked immunosorbent assay (ELISA) kit and gas chromatography–mass spectrometry (GC-MS). The results showed that MC-LR, MC-RR, and MC-YR could be efficiently decomposed by ClO₂. The degradation efficiency was shown positively correlated to the concentration of ClO₂ and reaction time; while the effect of reaction temperature and pH is slight. The kinetic constants and activation energies of the reaction of MC-LR, MC-RR, and MC-YR with ClO₂ are determined as 459.89, 583.15, 488.43 L·(mol·min)^-1 and 64.78, 53.01, 59.15 kJ·mol^-1, respectively. As indicated by high performance liquid chromatography mass spectrometer (HPLC-MS) analysis, degradation should be accomplished via destruction of Adda group by oxidation, with the formation of dihydroxy substituendums as end products. This study has provided a fundamental demonstration of ClO₂ serving as oxidizing disinfectant to eliminate microcystins from raw water source.     

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。     

高温燃烧水解-淋洗液在线发生离子色谱法同时测定煤中氟和氯

采用高温燃烧水解煤样-超纯水吸收装置,建立了高温燃烧水解-淋洗液在线发生离子色谱法同时测定煤中氟和氯的分析方法。系统、全面地考察了测定方法的影响因素,确定了最优高温燃烧水解预处理煤样和离子色谱法条件,并将该方法推广应用于飞灰、土壤和岩石的氟和氯含量检测,实验测定值与标准物质真实值误差能满足测定要求。     

滨河污水处理厂出水氯与紫外消毒对比试验研究

选择氯和紫外消毒技术对深圳滨河污水处理厂二级出水进行中试研究,比较了氯、紫外消毒技术的消毒效果、持续杀毒能力、消毒安全性、消毒成本和受水质量参数影响程度五方面内容并得到相应的数据以进行横向对比。据试验结果和该污水处理厂工程实际情况,推荐采用紫外污水消毒工艺。     

配水管网中与有机物反应的余氯衰减动力学模型

提出一级二级反应组合动力学模型,用大量实验数据拟合模型中的参数,模拟配水管网系统中余氯衰减的水体消耗部分.该模型定量反应了温度T、初始氯浓度c₀和TOC与余氯衰减之间的复杂关系.除初始阶段外,组合模型可简化为一级反应模型;T、TOC和c₀与余氯衰减之间的关系分别可简化为指数关系、正线性关系和负线性关系.该模型较好地解释了余氯衰减在初始阶段进行相对较快这一现象.实验数据验证的结果表明:该组合模型与实验数据吻合良好,优于传统的一级反应模型.