有机磷农药代谢产物分析的研究进展

长期低剂量接触有机磷农药(organophosphorus pesticides,OPs)可引起迟发性神经疾病,严重时有诱发突变和致癌作用.根据OPs的化学和毒理学性质,可以通过生物监测方法评价人体接触OPs的程度及其对健康可能产生的潜在影响.     

有机磷酸酯类化合物暴露对神经行为功能的影响

由于有机磷农药的长期广泛使用,使得有机磷暴露可能引起的长期健康效应越来越受到人们关注。在神经发育时期接触有机磷化合物、急性有机磷中毒或者长期低剂量接触有机磷都可能通过胆碱能毒作用机制和非胆碱能毒作用机制引起动物神经行为功能的长期改变。     

063 有机磷酸酯类化合物暴露对神经行为功能的影响

由于有机磷农药的长期广泛使用,使得有机磷暴露可能引起的长期健康效应越来越受到人们关注.在神经发育时期接触有机磷化合物、急性有机磷中毒或者长期低剂量接触有机磷都可能通过胆碱能毒作用机制和非胆碱能毒作用机制引起动物神经行为功能的长期改变.     

血、尿中有机磷农药及其代谢产物检测方法的研究进展

有机磷农药（OP）为有机磷酸酯类化合物，因具有低毒和低残留的优点而被广泛用作农业杀虫剂、杀菌剂、除草剂、植物生长调节剂等，目前OP占我国农药使用量的70％以上。长期低剂量接触可引起迟发性神经疾病，严重时可诱变和致癌。预防和处理OP引起的环境污染和食品污染等问题，首先需要及时、准确地检测有机磷，而评价人群OP的暴露剂量最有效的办法就是对人体体液中0P及其代谢产物进行直接监测。     

孕妇有机磷农药代谢产物暴露水平检测

有机磷农药(Organophosphorus Pesdcidcs,OPs)是目前世界各国农业生产中应用最广泛的农药.我国OPs使用量占农药总量的70%左右[1],因此,人们在生活中面临多途径的OPs暴露.已有动物以及人群研究均表明,OPs对胚胎发育存在影响[2-6].目前,OPs暴露评估主要方法为测定尿液中二烷基磷酸酯化合物(Diakyl phosphate,DAPs)的含量,而本次研究使用气相色谱法对孕妇人群孕晚期OPs暴露水平进行测定.     

035 血、尿中有机磷农药及其代谢产物检测方法的研究进展

有机磷农药(OP)为有机磷酸酯类化合物,因具有低毒和低残留的优点而被广泛用作农业杀虫剂、杀菌剂、除草剂、植物生长调节剂等,目前OP占我国农药使用量的70%以上.长期低剂量接触可引起迟发性神经疾病,严重时可诱变和致癌.预防和处理OP引起的环境污染和食品污染等问题,首先需要及时、准确地检测有机磷,而评价人群OP的暴露剂量最有效的办法就是对人体体液中OP及其代谢产物进行直接监测.     

甲基汞对脑发育的影响及机制研究进展

甲基汞具有很强的神经毒性，可引起中枢神经系统不可逆改变，发育中的脑对甲基汞尤为敏感。本文就胎儿期、哺乳期低剂量甲基汞暴露对脑发育的影响及其性别差异，甲基汞的神经毒性机制等方面进行综述。     

汞的免疫毒性研究进展

汞是严重危害人类健康的环境污染物，除引起中枢神经系统不可逆损伤外，还具有较强的免疫毒性。目前汞的污染呈现出浓度低、长期暴露的特点，多引起人体非典型、多系统的损害，而不单以神经症状为主。免疫系统作为人体对抗外来侵害的重要器官，在抗感染、抗肿瘤等多方面起主要作用，免疫系统的损伤必将带来对肿瘤和传染性疾病的易感性增高以及引发免疫功能紊乱等严重后果。     

国外有机磷农药神经发育毒性研究

有机磷农药目前占我国农药使用量的80%以上,长期低水平暴露对婴幼儿神经系统发育的影响不容忽视。有机磷农药毒作用机制研究甚多,众多研究表明,乙酰胆碱酯酶除水解乙酰胆碱外,还可能作为一种可分泌到胞外调控细胞增殖与轴突生长的神经营养因子,在神经系统发育的关键时期影响神经细胞的生长、分化和脑的正常功能。本文就近年来国外有机磷农药神经发育毒性研究概况及进展作一综述。     

117 国外有机磷农药神经发育毒性研究

有机磷农药目前占我国农药使用量的80%以上,长期低水平暴露对婴幼儿神经系统发育的影响不容忽视.有机磷农药毒作用机制研究甚多,众多研究表明,乙酰胆碱酯酶除水解乙酰胆碱外,还可能作为一种可分泌到胞外调控细胞增殖与轴突生长的神经营养因子,在神经系统发育的关键时期影响神经细胞的生长、分化和脑的正常功能.本文就近年来国外有机磷农药神经发育毒性研究概况及进展作一综述.     

有机磷农药暴露对胎儿及儿童神经发育影响的研究进展

继有机氯农药在20世纪80年代初被全面禁止使用后,有机磷农药就成为国内目前农业生产上应用最广泛、使用量最大的农药。随着近年来农业生产有机磷农药使用量的增加,其在人体内残留水平、对健康的危害尤其是对胎儿和儿童神经发育的影响引起人们极大的关注。笔者就有机磷农药在胎儿及儿童体内的残留水平以及对胎儿及儿童神经发育的影响进行了综述。     

Impact of low-level exposure to organophosphates on human reproduction and survival

Despite their widespread and longstanding use for the public good, organophosphate (OP) pesticides have led to many adverse effects on human health. Environmental exposure to OPs and adverse reproductive outcomes in men and women working on or living near farms are increasingly reported worldwide. The aim of the current review is to determine whether exposure to OPs, at levels lower than that which results in clinical manifestations of acute OP poisoning, leads to an adverse impact on fertility, growth and development, and to highlight possible effects for further investigation. There is evidence of impaired fertility due to a reduction in semen quality and possibly lower testosterone levels in exposed males. There is also evidence of impairment of fetal growth and development brought about by prenatal exposure to OPs. Paraoxonase gene (PON1) activity in the fetus and during early childhood makes the fetus and child more vulnerable to OP poisoning, suggesting that OP exposure has a greater impact on fetal and infant growth and development than on adults when exposed to the same concentrations of pesticides. This review raises concerns that exposure to OP pesticides at levels currently regarded as safe adversely affect human reproductive function and survival.     

Use of biomarkers to indicate exposure of children to organophosphate pesticides: implications for a longitudinal study of children's environmental health

Because of their history of widespread use in the United States and unknown long-term health effects, organophosphate pesticides (OPs) are being considered as a chemical class of interest in planning for the National Children's Study, a longitudinal study of children's environmental health. The availability and appropriate use of biomarkers to determine absorbed doses of environmental chemicals such as OPs are critical issues. Biomarkers of OP exposure are typically measured in blood and urine; however, postpartum meconium has been shown to be a promising matrix for assessing cumulative in utero exposure to the fetus, and studies are currently in progress to determine the utility of using saliva and amniotic fluid as matrices. In this article, we discuss the advantages and disadvantages of the currently available OP exposure monitoring methods (cholinesterase inhibition in blood, pesticides in blood, metabolites in urine and alternative matrices); study design issues for a large, long-term study of children's environmental health; and current research and future research needs. Because OPs are rapidly metabolized and excreted, the utility of one-time spot measurements of OP biomarkers is questionable unless background exposure levels are relatively stable over time or a specific time frame of interest for the study is identified and samples are collected accordingly. Biomarkers of OP exposure can be a valuable tool in epidemiology of children's environmental health, as long as they are applied and interpreted appropriately.     

有机磷农药接触工人酯酶活力特征及基因多态对酶活力的影响

目的 研究接触有机磷农药对丁酰胆碱酯酶（BchE）、羧酸酯酶（CarbE）、对氧磷酶（PonE）和乙酰胆碱酯酶（AChE）活力的影响,并探讨酯酶基因多态性对长期接触有机磷农药工人酯酶活力的影响.方法 241名长期接触有机磷农药的生产工人为直接接触组,151名农药厂后勤人员为间接接触组,160名无有机磷农药接触的外厂工人为对照组.检测各组4种酯酶活力;用ABI 7900基因序列检测系统和基因芯片技术确定PON192、PON55和BchE基因型.结果对照组CarbE、BchE和PonE活力无年龄、性别差异.直接接触组、间接接触组的CarbE和BchE活力均明显低于对照组;直接接触组PonE活力明显低于对照组;直接接触组AChE活力明显低于间接接触组,差异均有统计学意义（P＜0.01）.直接接触组BchE基因型（UU、UK、KK）频率分别为74.3%、24.1%和1.6%;等位基因频率BCHE＊U=0.863、BCHE＊K=0.137.PON192基因型（AA,AB,BB）频率分别为15.0%、45.5%和39.5%;等位基因频率PON＊A=0.378、PON＊B=0.622.PON55基因型（MM、LM、LL）频率分别为96.2%、3.8%和0%;等位基因频率PON＊M=0.981、PON＊L=0.019.PON192和PON55不同基因型PonE活力差异有统计学意义（P＜0.01和P＜0.05）.结论 长期接触有机磷农药在不同程度上抑制4种酯酶的活力,PON192和PON55基因多态性影响有机磷接触工人PonE活力.     

Airborne concentrations of organophosphorus pesticides in Korean pesticide manufacturing/formulation workplaces

Pesticide manufacturing/formulation workers rather than farmers or applicators or people living with them are primarily exposed to organophosphorus pesticides (OPs). However, airborne concentrations in the workplace have rarely been determined. A total of 121 air samples (personal or area sampling) were collected at 4 factories where chlorpyrifos, EPN, parathion, and phorate, were manufactured/formulated from March through July, 2007-2008. Samples were collected by the National Institute for Occupational Safety and Health (NIOSH) method and were analyzed by GC-MS. The geometric mean (GM) level of airborne chlorpyrifos was 0.17 mg/m(3), 85% Korean Occupational Exposure Limit (KOEL) of 0.2 mg/m(3), and at 95% confidence, airborne concentrations exceeded the KOEL 58.8% of the time or less, indicating that this concentration level was unacceptable according to exposure assessment using a LogNorm2(?). However, compared with levels of TLV and/or PEL and/or WEL, the GM concentration levels of other OPs were remarkably low (range, 0.1-15.0%) and that these levels of concentrations to the other OPs were acceptable. The levels of airborne concentrations of OPs depended on isolation of the process; in other words, the levels depended on the extent to which the process was automated. The reason that the airborne concentration levels, except for those of chlorpyrifos, were very much lower than expected may be attributable to the fact that there was not exposed to 100% toxic active ingredients in pesticide formulation workplaces because of the use of supplemental agents or additives to produce complete pesticides. This study is limited since there were seldom or neither any data of previous studies to be compared with the study results nor dermal exposure data. The results were used to revise KOELs for OPs in 2010.     

Dialkyl phosphate metabolites of organophosphorus in applicators of agricultural pesticides in Majes – Arequipa (Peru)

Background  

Organophosphorus (OPs) pesticides are the most commonly used pesticides in Peruvian agriculture. The population at risk for OPs exposure includes formulators, applicators and farmers. Majes Valley is the most important agricultural center of the Southern region of Peru. The present study was aimed to determine the knowledge about using OPs, safety practice and urinary dialkylphosphate metabolites on OP applicators in the Majes Valley, Peru.     

Estimation of cumulative exposure to organophosphate sheep dips in a study of chronic neurological health effects among United Kingdom sheep dippers

OBJECTIVES—To derive a method for retrospectively estimating cumulative exposure to organophosphate (OP) pesticides among a cross section of United Kingdom sheep dippers, as part of a wider epidemiological study of neurological abnormality within this group of workers.
METHODS—A hygiene study of dipping sessions at 20 farms using diazinon based dips was carried out by two experienced occupational hygienists. Observations on the exposure of people to concentrate and dilute dip were recorded throughout each dipping session, together with the other relevant factors including the use and condition of protective clothing. Concentrations of urinary metabolites of diazinon were used to measure actual exposure to OPs. To estimate exposure in the subsequent epidemiological study, an occupational exposure history questionnaire was developed using results from the hygiene study and an empirical exposure model.
RESULTS—In the hygiene study, increased urinary metabolites were associated with the handling of concentrate dip and exposure to dilute dip wash through splashing. Very few dippers wore the recommended protective clothing. The handling of concentrate dip was the principal source of exposure to OPs. Dipping task was used as a surrogate for splashing of dilute dip in retrospective exposure estimation. In the epidemiological study, cumulative exposure to OP sheep dips was highly correlated with the total number of dipping days, but not with age.
CONCLUSIONS—Sheep dip concentrate is the most important source of OP exposure among sheep dippers and estimates of exposure to OPs during routine dipping should take due account of exposure to concentrate dip as well as to the dilute dip wash. The observed use of recommended protective clothing by most subjects was insufficient to allow a proper empirical assessment of its effectiveness.


Keywords: organophosphate pesticides; sheep dip; exposure model     

农药职业接触的生物监测指标

近年来,随着生产环境的改善,有效管理和防护措施的采取,农药职业接触中急性中毒病例已较前明显减少,而长期低剂量接触农药所致的健康危害则越来越引起重视.这些危害通常在临床症状出现前即已发生,因此对农药职业接触者进行生物监测不仅有助于对农药这一职业性有害因素进行全面评价,而且对控制和降低人体接触水平、预防职业危害有着重要意义.该文总结了可以用于农药职业接触者的生物监测指标,期望对实际工作有所帮助.     

Toxicity of Stormwater Runoff After Dormant Spray Application of Diazinon and Esfenvalerate (Asana®) in a French Prune Orchard,Glenn County,California, USA

Organophosphate pesticides (OPs), in particular diazinon and chlorpyrifos, have frequently been detected in toxic concentrations in waterways draining agricultural and urban areas in California’s Sacramento and San Joaquin River watersheds (US Geological Survey 1997, Werner et al. 2000). Toxicity has in part been linked to stormwater runoff of OP pesticides applied during the dormant season on stonefruit and almond orchards (Foe and Sheipline 1993; Kuivila and Foe 1995). State Water Quality Plans have now been implemented by regulatory agencies to prevent movement of OPs into surface water, and growers have reduced the application of OPs. Simultaneously, the use of so-called reduced-risk alternatives, such as pyrethroid insecticides and Bacillus thuringiensis bloom sprays, has increased dramatically (Epstein et al. 2000).

Best management practices (BMPs) are aimed at reducing off-site movement of pesticides into surface waters. Pyrethroid pesticides, among them the widely used esfenvalerate (Asana®) are considerably more hydrophobic (solubility in water: 0.4 μg/L) than the relatively soluble OP pesticide diazinon (solubility in water: 40,000 μg/L; Extoxnet 2001). Although runoff of pyrethroids is believed to be minimal thus reducing pesticide impact on surface waters, esfenvalerate has been shown to be toxic to fish at extremely low concentrations (≤ 1 ug/L; Haya 1989; Clark et al. 1989; Lozano et al. 1992), and potentially poses a significantly higher risk to these organisms than OP pesticides. In addition, its potential to bioaccumulate and bioconcentrate is high (Smith and Stratton 1986). A second recommended method for reducing toxic runoff from orchards is the use of different orchard floor cover crops. Cover crops are believed to enhance water infiltration (Hargrove 1991).

This study was performed to measure the effectiveness of these two BMPs in reducing the toxicity of Stormwater runoff. Experiments were carried out in a French prune orchard at the Talbot-Vereschagin Ranch, Glenn County, California.

     

Problems in monitoring overexposure among spray workers in fruit orchards chronically exposed to diluted organophosphate pesticides

Objectives: Farmworkers applying diluted pesticides are chronically exposed to low levels of toxic substances such as organophosphates (OPs). Monitoring of serum and red cell cholinesterase (ChE) levels are often used to determine whether these workers are overexposed to OPs. There are major problems with the interpretation of ChE levels: differing definitions of `overexposed'; measurement variation and biological variation over time; and confounding factors such as alcohol misuse and certain liver conditions. The purpose of this study was to conduct a survey under field conditions to determine the extent of possible overexposure and the problems with biological monitoring using ChE levels in a spray worker population chronically exposed to OPs. Methods: A survey of 134 spray workers from 44 deciduous fruit farms in the Western Cape, South Africa, was conducted three times during the production season. Both ChE levels were determined at the end of 6 months lay-off (no spraying); during peak spraying; and at the end of the spray season. A group of 51 packshed workers with no exposure to OPs was used for comparison. Results: Despite exhaustive statistical analyses, the proportions of lowered ChE levels could not be shown to differ between the exposed and unexposed groups. The variation in ChE levels observed could be explained statistically by the high levels of alcohol misuse among the participants (76% in the exposed group, 59% in the unexposed group). Unhealthy lifestyle habits were highly prevalent amongst these workers (e.g. 83% smoked), which have long-term implications for their health and, importantly, hamper the diagnosis of overexposure. Alcohol intake was statistically associated with lowered ChE levels. Conclusions: According to different definitions of `lowered', different conclusions could be reached, which hamper reliable application in the field. The interpretation of ChE levels as an indicator of overexposure to OPs is complex, and the risk of misinterpretation in such a worker population is considerable.