林丹的作用机制

本文根据动物染毒后的生理生化效应.离体培养和模型试验的结果,重点介绍了林丹作用机制研究的进展情况.     

林丹的致敏、致畸和致突变作用

本文通过涂抹、口服、灌胃、注射、离体培养等方法的研究结果,全面的评价了林丹的致敏、致畸和致突变作用,尽管阳性与阴性结果均有报道,但基本结论是林丹对哺乳动物不存在致敏、致畸和致突变作用.     

林丹对鸟类和其它动物的影响

本文通过一些典型动物试验和离体培养试验,介绍了林丹对鸟类和哺乳类动物的毒性、中毒特征和某些作用机制.     

林丹环境安全性评价研究

为了评价林丹在环境介质中的持久性,对林丹的土壤降解、水解、光解与快速生物降解性进行了试验研究。结果表明,林丹的土壤降解半衰期为36．9～68．6d,水解半衰期为8．94～2310d,对光反应稳定,难以快速生物降解。林丹对斑马鱼的96h—LC50为4．22μg·L^-1,对环境生物具有极高的毒性;林丹在金鱼体内的生物富集系数BCF〉1000,具有较高的生物富集性。根据试验结果推断,林丹在环境介质中具有极强的稳定性,很容易在食物链中发生生物积累。     

林丹对环境的污染及其致癌作用

本文较详细地介绍了林丹在环境要素中的残留状况,消解趋势,代谢途径和主要降解产物。同时还引用了一些研究结果说明林丹不是致癌物,不可能在环境中无限期累积对人体健康构成威胁。     

世界林丹的生产与销售

林丹是一种比较安全的有机氯杀虫剂,在国外广泛用于农业、林业害虫防治。由于林丹是从六六六原粉中提取出来的丙体——六六六,在我国停止生产和使用六六六的过程中,也影响到林丹的推广使用。林丹虽来自六六六,但又不同于六六六,它是六六六中唯一的有效成分。因此,把林丹视为禁用品种是一种事出有因,缺乏科学依据的误解。本文从林丹的生产工艺和对无效体的综合利用,林丹在国外的生产与销售形势、应用范围和研究近况等方面为澄清这种误解提供了一些证据。     

不同培养条件对堆肥中降解纤维素林丹复合菌系分解能力的影响

该论文作者对一组高效降解纤维素林丹的复合微生物菌系在不同培养条件下的降解能力进行了研究,结果表明,该复合菌系对滤纸、脱脂棉、稻秸粉和锯末等不同纤维素材料均有较强的降解能力,但相比之下对天然纤维素含量高的碳源(如滤纸、脱脂棉)降解效果更好.最佳的碳源浓度为0.5%和1%.有机复合氮源对降解效果的影响明显优于无机氮源,氮源浓度以0.25%和0.5%为宜.它能在较大的pH值范围内均保持高的纤维素降解活性,但在中性及偏碱环境中活性最强.在纤维素降解最佳的pH值7～9范围内,也同样有利于林丹的降解,而在纤维素降解较少的pH值为10的条件下,林丹的降解率仍高达49.6%.培养复合菌系的溶解氧范围以0.07～0.13 mg/L,为宜,最适生长和降解纤维素林丹的温度为50～60℃.     

林丹在土壤中的残留动态研究

采用气相色谱法测定林丹在土壤中的残留动态。在自然状况下,林丹在土壤中的降解很快,２０ｄ后,灌淤土和灰漠土中降解率分别为３９９１％与４１２２％,两个月后降解分别达９９５９％和９９６９％。棉花种子及油菜种子经林丹拌种后,在土壤中的残留量很低,与不拌种的土壤残留相近。用干种子重量的０１５％林丹拌种,拌种棉田土壤中林丹的平均残留量为０００４２ｍｇ／ｋｇ,不拌种土壤中为０００２７ｍｇ／ｋｇ;油菜种子拌种土壤中平均残留量为０００３８ｍｇ／ｋｇ,不拌种的土壤中为０００１０ｍｇ／ｋｇ。棉花、油菜采用林丹拌种对土壤的污染是微不足道的。试验结果还表明,林丹在土壤中的残留量随用药浓度的提高而增加。     

林丹对微生物及水生生物的毒性

本文介绍了林丹对微生物和水生生物的毒性、中毒症状及潜在危险.     

赭曲霉毒素A引起HepG2细胞损伤及DNA甲基化水平降低

赭曲霉毒素A (ochratoxinA,OTA)是一种污染食品的真菌毒素,对许多动物具有肾毒性,肝毒性,免疫毒性,致畸和致癌作用.本研究以人肝癌细胞HepG2为体外模型,研究OTA引起的细胞损伤及对DNA稳定性的影响.MTT结果显示,OTA能抑制HepG2细胞的生长,存在时间剂量——效应关系.OTA引起细胞上清中酸脱氢酶(LDH),谷草转氨酶(GOT)和谷丙转氨酶(GPT)活性的升高,诱导细胞内活性氧(ROS)生成,降低超氧化物歧化酶(SOD)活力.彗星实验结果显示OTA引起DNA链断裂,形成拖尾现象.同时,本研究还首次研究了OTA对DNA甲基化的影响.HPLC/MS/MS结果显示,经OTA处理后的细胞,其DNA中5-甲基脱氧胞苷(5mdC)百分数显著低于对照组.这些结果表明OTA会抑制HepG2细胞生长,引起氧化损伤,破坏DNA的稳定性和完整性.本研究表明OTA引起的肝毒性可能与氧化损伤和DNA损伤有关.     

林丹对鼠的毒性

本文介绍了林丹的不同剂型、染毒量和给药方式对鼠类的毒性、中毒症状及其影响因素.     

Lindane Biodegradation by Defined Consortia of Indigenous Streptomyces Strains

The current study aimed to compare lindane degradation by pure and mixed cultures of Streptomyces sp. Cell-free extracts were assayed for potentiating dechlorinase activity and, based on these results, consortia of two to six microorganisms were assayed for their growth on and degradation of lindane. Furthermore, the role of bacterial consortia of lindane-degrading strains was examined in lindane decontamination soil assays. Four actinobacteria, previously isolated from a pesticide-contaminated area, were selected because of their tolerance to lindane and their ability to use the pesticide as sole carbon source. These strains as well as Streptomyces sp. M7 and Streptomyces coelicolor A3 were used to study specific dechlorinase activity (SDA) and lindane removal in mixed cultures. Pure cultures presented SDA in the presence of 1.66 mg L^-1 lindane as carbon source. SDA was improved by certain mixed cultures until 12 times compared with pure cultures. Mixed cultures with two, three, and four strains showed maximum lindane removal of 46% to 68%, whereas combinations of five and six strains did not efficiently remove the pesticide from the culture medium. The Streptomyces sp. A2, A5, M7, and A11 consortium presented the lowest ratio between residual lindane concentration and SDA and could be a promising tool for lindane biodegradation.     

<Emphasis Type="Italic">Withania somnifera</Emphasis> Dunal-mediated dissipation of lindane from simulated soil: implications for rhizoremediation of contaminated soil

Background, aim, and scope  

Lindane is an organochlorine chemical that has been used both as an agricultural insecticide and as a treatment for head lice and scabies. It is a neurotoxin that interferes with GABA neurotransmitter function. In humans, lindane primarily affects the nervous system, liver, and kidneys and may be a carcinogen and/or endocrine disruptor. Currently, India is the largest consumer and producer of lindane in the world. Due to its continuous use and indiscriminate industrial production, lindane-contaminated soils are widespread in the country. Apart from India, historical lindane production sites were found in Austria, France, Spain, Bulgaria and in China, Turkey, and the former USSR. Before 1984, lindane was also manufactured in the German Democratic Republic, Poland, Yugoslavia, Romania, and Hungary; since then, all production has been stopped in Germany, Japan, The Netherlands, the UK, and the USA. Because of its worldwide use for more than 50 years, lindane-contaminated soils can be found in most countries of the world. Although many countries have restricted or eliminated its usage, obsolete stock piles continue to pose a threat to various ecosystems and human health. Physical, chemical, and biological methods can all be used for the remediation of contaminated sites, but phytoremediation is now recognized as a cost-effective method for the decontamination of soil sites. The present study examines the potential of Withania somnifera Dunal (previously shown to accumulate lindane from contaminated industrial area; Abhilash et al., Chemosphere 72:79–86, 2008) to take up lindane (γ-HCH) and the subsequent plant-mediated dissipation of lindane from an artificially contaminated soil.     

Gas chromatographic determination of lindane (gamma isomer of BHC) in maneb-lindane liquid pesticide formulations

Lindane from liquid insecticide-fungicide formulations containing lindane with maneb can be determined by gas chromatography using 3% OV-1 or 5% SE-30 columns. Lindane is extracted with acetone, and an aliquot is diluted to volume with anhydrous methanol and injected on-column. The internal standard, diethyl phthalate, has a retention time of 6 min and lindane has a retention time of 12 min, allowing injection every 15 min. Within-laboratory analysis of 3 typical formulations indicates good precision with coefficients of variation ranging from 0.45 to 1.58%. The method can be easily adapted to other liquid or dust formulations of lindane.     

林丹对人的毒性作用

本文根据自愿受试者、职业中毒、意外中毒和企图自杀接触林丹后的临床表现,结合理化检验,较全面地概括了林丹的中毒特征为呼吸加快,痉挛,惊厥,运动失常,口腔出血,昏迷,脑电图紊乱,谷丙及谷草转氨酶、乳酸脱氢酶等活性升高,肝脏出现脂肪性病变或损坏.但一般经过治疗均可恢复.     

Gas chromatographic methods for determination of gamma-BHC in technical emulsifiable concentrates and water-dispersible powder formulations and in lindane shampoo and lotion: collaborative study

Although the gas chromatographic separation of the isomers of BHC was demonstrated two decades ago, the present AOAC method of analysis of BHC for gamma-isomer (lindane) content is based on a separation carried out on a liquid chromatographic partition column. A method of analysis has been developed that uses an OV-210 column for separation of the gamma-isomer from the other isomers and impurities in technical BHC. Di-n-propyl phthalate was chosen as an internal standard. The same system allows quantitation of lindane in lotion and shampoo after these products are extracted with ethyl acetate-isooctane (1 + 4). The analytical methods were subjected to a collaborative trial with 10 laboratories. The coefficient of variation for technical BHC was 2.83%. For the water-dispersible powder and emulsifiable concentrate, the coefficients of variation were 2.89% and 4.62%, respectively. Coefficients of variation for 1% lindane lotion and shampoo were 4.36% and 11.92%, respectively. The method has been adopted official first action.     

Effect of lindane and DDT on populations of protozoa in a garden soil

Applications of lindane and p,p'-DDT to a garden soil at rates of 5 and 50 parts/10⁶ inhibited soil protozoa. The inhibitory effect of DDT was still apparent 3 months after application but that of lindane, although noted at the time of application and after 1 month, was not detectable after 2 months' incubation of the treated soil.