广州部分区域表层土壤中有机氯农药分布特征

通过在冬、夏两季对广州市部分市区和远郊区的表层土壤样品中OCPs(有机氯农药)的采样和气相色谱-电子捕获检测法分析,对OCPs残留现状进行了研究.结果表明,土壤中w(HCHs)为0.29～14.90 ng/g,未超过GB 15618—1995《土壤环境质量标准》的一级自然背景值.w(DDTs)为nd～697.70 ng/g.海珠区和黄埔区部分地点w(DDTs)超过一级自然背景值.DDTs为主要残留有机氯农药,平均占w(OCPs)的85.1%.所观察到的较低的w(α-HCH)/w(γ-HCH)(小于1)和w(γ-HCH)>w(β-HCH)的结果,有可能是林丹输入所致.一些地点可能有新的DDT输入.按土地利用类型划分,表层土壤中w(OCPs)为工业区>农田>果园>未利用地>居民区绿地>森林公园.      

Tenax萃取技术用于养殖底泥中有机氯农药的生物有效性研究

本研究以经济底栖生物菲律宾蛤仔和河蚬为受试生物,分别对不同浓度梯度的海洋和淡水底泥中9种代表性有机氯农药(OCPs)进行累积实验;同时采用Tenax连续萃取法研究2类底泥中OCPs的脱附动力学,提供简单、快速评价养殖底泥中OCPs生物有效性的方法,并将Tenax萃取结果与2种底栖生物的累积结果进行比较。结果表明,菲律宾蛤仔和河蚬对OCPs的生物-底泥富集因子(BSAF)分别为0.31~1.89和0.12~2.12,且底泥中有机碳标化的OCPs浓度与生物体内脂肪标化的OCPs浓度之间的相关性较差。Tenax脱附动力学的结果表明,2类底泥中OCPs的快速脱附比例(F_(rap))均在50%左右,其快速、慢速和极慢速脱附速率常数数量级分别为10~(~(-1))、10~(-2)和10~(-4)。Tenax快速脱附组分与2种底栖生物累积结果之间具有良好的相关性(r~2=0.75,P0.0001),表明Tenax萃取技术可以预测OCPs在底栖生物体内的累积量,并且该方法克服了大型底栖生物累积实验结果重复性较差等缺点。另外通过与基于热力学平衡的方法对比发现,Tenax萃取技术更适用于滤食性或可消化底泥的底栖生物对底泥污染物的富集;同时Tenax 6 h和24 h单点萃取技术可以作为简单快速评价底泥疏水性有机污染物(HOCs)生物有效性的替代方法,进一步为养殖领域的底泥污染状况以及相关水产品的质量安全和食用风险提供生物有效性评价依据。     

3种典型有机氯农药对锦鲤幼鱼的雌激素效应及其体内富集

为研究3种典型有机氯农药(%-六六六、p,p'-DDT和七氯)低浓度暴露对锦鲤幼鱼的雌激素效应及其体内富集效应,将锦鲤幼鱼暴露于有机氯农药的6个浓度组中进行20 d慢性毒性试验,测量血清中游离钙和蛋白结合磷含量及体内各组织有机氯农药残留。结果表明,在低浓度暴露20 d后,锦鲤幼鱼血清中游离钙和蛋白结合磷含量均随暴露浓度增加而呈先增后减之势,产生了明显的雌激素效应。p,p'-DDT在鱼体各组织中的富集能力远高于%-六六六和七氯;p,p'-DDT主要在鱼油中富集,其次为鱼肝、鱼鳃和鱼皮;%-六六六和七氯主要在鱼肝中富集,其次为鱼皮、鱼鳃和鱼油;3种有机氯农药在鱼肉中的富集相对较少。     

树皮在大气有机氯农药监测中应用的研究进展

有机氯农药（Organochlorine pesticides, OCPs）曾在全世界被大量使用,即使禁用多年,仍能在各种环境介质中被广泛检出,对生态环境和人体健康存在着潜在的威胁。因此OCPs的环境迁移和归趋一直是该领域的研究热点。树皮是一种天然的被动采样器,能够很好的反映出大气有机物长期的污染程度。本文简要论述了树皮作为被动采样器在大气污染物监测研究中应用的优势,并对OCPs在树皮中的残留浓度、特征及影响其富集的因素进行了探讨,最后特别针对具有手性的OCPs在树皮中的对映体选择性特征进行了评述。     

农药内分泌干扰效应研究进展

农药作为农业生产过程中的一类重要生产资料,主要用作杀虫剂、杀菌剂和除草剂等。由于农药的大量使用,目前在各类农产品及各种环境介质中都能被检测到,对饮食安全和环境健康带来潜在危害。研究发现,许多农药为内分泌干扰物,其能够干扰人类和其它生物体的内分泌系统正常功能。本文在总结国内外相关研究的基础上,对农药内分泌干扰效应的作用机理及筛选模型进行总结,对有机氯、有机磷和拟除虫菊酯等各类农药的内分泌干扰效应研究进展进行综述,并提出深入探究农药致毒作用机制和低剂量下多种农药联合毒性是本领域的重要研究方向。     

有机氯农药在东方白鹳组织里的浓度

对越冬迁徙期间中途停留在天津北大港的野生鸟类-东方白鹳（Ciconia boyciana）体内肌肉、肝脏、心脏、胃和脾中∑OCPs浓度进行了检测.各组织中检出的∑OCPs平均浓度（浓度范围,以脂重计）在心脏中最高,为955.30ng/g（88.65～4102.577ng/g）,次之为肝脏,平均浓度为465.55ng/g（37.96～1476.17ng/g）,再次之为胃、脾和肌肉,浓度分别为251.64ng/g（102.88～354.61ng/g）、176.5ng/g（158.72～194.50ng/g）和143.96ng/g（10.90～800.51ng/g）.在肝脏和心脏中∑DDTs和浓度高于∑HCHs,在其它组织中则相反.与其它研究相比,本研究所检测鸟体内有机氯浓度较低,表明这批东方白鹳并尚未受到环境中OCPs的严重污染.     

Application of QSARS to predict potential aquatic toxicities of organochlorine pesticides∗

On the basis of physico‐chemical data, such as water solubility and vapour pressure as well as acute toxicity tests we developed an ecotoxicological model for preliminary hazard assessment. By use of the reciprocal product from log H and LC₅₀ we developed a suitable ranking system that allows us to predict potential damage to aquatic organisms through pesticides.     

Nerve conduction studies in sprayers occupationally exposed to mixture of pesticides in a mango plantation at Lucknow,North India

In this study, nerve conduction, organochlorine (OC) pesticide residues in blood and cholinesterase activity levels of pesticide sprayers employed in mango plantations at Lucknow, North India, were determined. Fifty-two sprayers from mango plantations who regularly spray mixture of pesticides like organophosphates (OP), OCs, and carbamates were considered as exposed group. Eighteen subjects with similar socio-economic status of exposed group, who do not handle pesticides, were selected as controls. Questionnaire-based interviews related to personal and occupational histories of the study subjects were carried out. Sprayers did not use any personal protective equipment during pesticide handling. The blood-pesticide analyses of sprayers show higher mean values of hexachlorohexane (HCH), γ-HCH, δ-HCH, total HCH, op-DDT compared with the controls. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activites were significantly reduced among sprayers. Risk of motor nerve conduction deficits was observed in sprayers with low AChE activity. Negative correlation of motor and sensory nerve conduction deficits was observed with the duration of exposure and age among sprayers. The study demonstrated that the prolonged exposure to mixture of pesticides, ergonomic factors, decline in cholinesterase activity may lead to nerve conduction dysfunction. The findings suggest the need for controlled use of pesticides in the plantation and indicated the need for training and implementation of hygiene practices like proper usage of personal protective equipments.     

Study of Fishes in the Chung-Kung Stream: Species Distribution and Organochlorine Pesticide Residues

Abstract

In this study, we investigated the potential for reductive dechlorination of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) by municipal sewage sludge adapted to 2,4-DCP at different concentrations. 2,4-DCP was completely dechlorinated within 4 weeks. After 18 weeks' incubation, 2,4,6-TCP was also completely dechlorinated and the residue of PCP was 0, 44.46, 51.96% at 0.5, 5, and 50 μg ml¹ respectively. the 2,4-DCP adapted communities initially removed the ortho-chlorine from PCP of 5.0, 50 μg ml¹, following an ortho < para < meta order of chlorine removal. Intermediate products were 3,4,5-TCP, 3,5-DCP, 3-CP (3-chlorophenol), phenol, benzoate and hexanoic acids, whereas PCP (0.5 μg ml¹) indicated a preference for meta-chlorine removal. the intermediate product of 2,4,6-TCP at three concentrations were 2,4-DCP, phenol, benzoate and hexanoic acid. These products were identified by GC-MASS spectrometry. the effects of supplements, including sodium citrate (0.08 mM), sodium pyruvate (0.18 mM), sodium sulphate (0.14 mM) had a direct stimulatory effect on the dechlorination of 2,4,6-TCP and PCP after treatment for 4 weeks, but dechlorination was inhibited after 8 weeks.     

Organic pollutants in snow of urban and rural Russia and Finland

To check the effect of possible deposition of organic contaminants in northern regions of the Earth due to atmospheric transport snow samples were collected in early March in 6 places in Russia and 4 in Finland including arctic territories. GC‐MS was used as an analytical tool to identify and quantify individual organic compounds belonging to the various classes. As a result more than 250 compounds were detected. The possible presence of more than 100 other priority pollutants from the US EPA list was also screened.