光催化降解表土层中DDT的影响因素研究

通过选用添加适量滴滴涕（DDT）的棕壤土,以紫外灯为光源进行光催化降解实验,研究土壤的水分含量、溶解性有机质（DOM）含量、pH值、不同的外源投加物质以及翻动土壤等各因素对于土壤中DDT光催化降解的影响,探讨光催化降解DDT的最优化条件。实验结果表明：随着水分含量的增加,DDT的降解率呈逐渐增大的趋势;当水分含量达50%时,DDT降解率达到最高,达67.5%;当水分含量超过50%后,DDT降解率呈缓慢下降趋势。在一定范围内,DDT的光催化降解率随溶解性有机质含量的增加而增加,但当溶解性有机质的含量超过1.0%时,降解率反而降低;和中性条件相比,DDT在酸性和碱性条件下都具有更高的光催化降解率;投加铁粉、Ti02对土壤中DDT的降解速率有明显的提高;溶解性有机质、Fe2O3、全元素肥料混合溶解性有机质对DDT的光催化降解效果略有提高,而单独加入全量元素肥料几乎对降解率没有影响;DDT的光催化降解率随着土层深度的增加而降低;定期翻动土壤可以有效提高DDT的光催化降解率。     

DDT对花生种子生活力和发芽的影响

利用TTC和水培方法研究了DDT对花生种子生活力和发芽的影响,结果显示,用浓度为4mg/kg-128mg/kg的DDT溶液培养5d的种子其生活力和活力指数皆显著增加,而对发芽率和发芽指数没有显著影响。关于DDT对花生种子的刺激作用及其机理,尚需深入研究。     

DSC and Raman study on the interaction of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane] with liposomal phospholipids

In this paper, a DSC and Raman study of hydrated multilamellar DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) and DMPE (1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine) liposomes in presence of increasing amounts of DDT is reported.The observed changes denote that DDT molecules interact with both phospholipids and that the interaction mainly involves the external part of the bilayer since the deep penetration into the hydrophobic core is prevented by the setting up of polar interactions between the three aliphatic C-Cl bonds of the trichloro group of DDT and the -N⁺(CH₃)₃ of DMPC or the -NH₃⁺ groups of DMPE molecules.This behaviour was particularly evidenced in presence of DMPE, as the insertion of DDT molecules into the central part of the bilayer seems to be completely excluded.Moreover, in DMPE liposomes the overall structure of the bilayer changes to a well defined and structured ‘phase II’ in presence of even small DDT amounts.     

Pyrethroids, knockdown resistance and sodium channels

Knockdown resistance to DDT and the pyrethrins was first described in 1951 in the housefly (Musca domestica L.). This trait, which confers reduced neuronal sensitivity to these insecticides, was subsequently shown to confer cross-resistance to all synthetic pyrethroid insecticides that have been examined to date. As a consequence, the worldwide commercial development of pyrethroids as a major insecticide class over the past three decades has required constant awareness that pyrethroid overuse has the potential to reselect this powerful resistance mechanism in populations that previously were resistant to DDT. Demonstration of tight genetic linkage between knockdown resistance and the housefly gene encoding voltage-sensitive sodium channels spurred efforts to identify gene mutations associated with knockdown resistance and understand how these mutations confer a reduction in the sensitivity of the pyrethroid target site. This paper summarizes progress in understanding pyrethroid resistance at the molecular level, with particular emphasis on studies in the housefly.     

长江宜昌江段铜鱼和中华鲟体内HCH DDT的残留水平

采用毛细管电子捕获气相色谱(GC-EcD)法检测了长江宜昌汀段捕获的野生园口铜鱼(Coreius guichenoti)和野生中华鲟(Acipenser sinensis)体内六六六(HCH)、滴滴涕(DDT)的残留量.结果表明,1-5龄园口铜鱼肌肉、脂肪和肝脏组织中,HCHs(HCHs=α-HCH+β-HCH+γ-HCH+δ-HCH)残留量分别为2.3～5.9 ng·g-1,4.2～15.1 ng·g-1和9.5～38.7 ng·g-1;DDTs(DDTs=p,p'DDE+o,p'-DDT+p,p'DDD+p,p'-DDT)分别为22.4～37.1 ng·g-1102.3～173.8 ng·g-1和181.1～410.0 ng·g-1.中华鲟肌肉组织和卵中,HCHs分别为5.2和15.8 ng·g-1,DDTs分别为70.3和521.7 ng·g-1.在HCHs中,γ-HCH为主要检出物,占HCHs的73.3%;p,p'-DDE是鱼体中DDT的主要存在形式,占DDTs的67.7%.中华鲟精液中未检出HCHs、DDTs.     

DDT降解菌DH-7的分离鉴定与降解特性研究

[目的]研究DDT降解菌的生物学、降解特性及其发酵条件的优化。[方法]从化工厂采集土样,分离、筛选到1株能够在好氧条件下DDT降蟹率较高的菌株DH-7,并对其进行研究。[结果]通过16SrDNA序列分析结合传统分类学方法初步确定菌株DH-7为铜绿假单胞菌。对菌体降解DDT特性的研究表明,该菌株对DDT降解10d的降解率为73．6％。在优化培养条件后,该菌株10d的降解率达81．4％。[结论]该研究结果为DDT污染土壤的生物修复提供依据。     

酶联免疫吸附方法分析海水和贝类中的滴滴涕及代谢物

采用间接竞争酶联免疫吸附分析(Ind irect Competitive Enzym e-linked Immunosorbent Assay,ELISA)方法测定海水样品和海洋贝类中的有机氯农药滴滴涕及其主要代谢产物的含量。采用碳二亚胺法,将半抗原DDA分别与载体蛋白牛血清白蛋白(Bovine serum album in,BSA)和卵清蛋白(Ovalbu-m in,OVA)偶联,得到包被抗原和免疫抗原。以DDA-OVA作为免疫抗原,免疫雌性BALB/c小鼠,免疫数次后,测定血清中抗体效价。以DDA-BSA为包被抗原,免疫多克隆抗血清为多克隆抗体,建立间接竞争酶联免疫吸附方法分析检测海水样品和海洋贝类中的有机氯农药二氯二苯三氯乙烷(DDT)及其代谢产物2,2-双(4-氯苯基)乙酸(DDA)、2,2-双(4-氯苯基)-1,1-二氯乙烷(DDD)、2,2-双(4-氯苯基)-1,1-二氯乙烯(DDE)的方法。最低检出限分别为DDT:25 ng/m l,DDA:1.56 ng/m l,DDD:25 ng/m l,DDE:25 ng/m l。贝类样品DDA回收率为96.37%~100.88%,批内变异系数为2.28%~5.13%;贝类样品DDT回收率为93.86%~100.08%,批内变异系数为4.71%~7.68%;海水样品DDT回收率88.23%,批内变异系数6.60%。     

广东沿海牡蛎体中BHC和DDT的变化趋势

本文根据１９８９－１９９３年广东沿海１０个地点牡蛎体ＢＨＣ和ＤＤＴ的测定数据，论述了广东沿海牡蛎体ＢＨＣ和ＤＤＴ的变化趋势。牡蛎体ＢＨＣ和ＤＤＴ含量的空间分布格局，１９８９年以前呈珠江口海区明显高于粤东和粤西海区的特点，１９８９年以后三个海区间已无显著差异。牡蛎体ＢＨＣ和ＤＤＴ含量的时间变化趋势相似，均表现出１９８３—１９８９年和１９８９—１９９１年两个明显下降时段。１９９２年以后，牡蛎体中二者的含量均已降至检测限水平     

近十年我国DDT文献研究分析及替代技术进展

通过CNKI数据库进行检索,并借助文献计量,以年度分布、主要作者、研究机构等为指标分析了我国自2009年禁止生产、流通、使用和进出口DDT开始在DDT禁止前后5年内的研究现状;在DDT的替代技术方面,国内含DDT防污漆的替代技术得到了GEF的资金支持,目前已研发出无毒无害的产品,并开始工业化生产.     

比较四种提取技术分析沉积物中滴滴涕同系物

Four techniques, Soxhlet extraction （SOX）, ultrasonic extraction （USE）, fluidized-bed extraction （FBE） and accelerated solvent extraction （ASE） with different solvents （methanol, hexane/acetone and acetonitrile） were used for the extraction of DDT analogues in sediments. Results revealed that the four extraction techniques had high recoveries （〉 86.0%） with low standard deviations （〈 12.0%） for most of DDT analogues, meaning that they could all successfully extract DDT analogues in sediments. Accelerated solvent extraction using methanol and hexane/acetone （1：1）, fluidized-bed extraction using hexane/acetone （1：1） and the ultrasonic extraction using hexane/acetone （1：1） were comparable or better than Soxhlet extraction using hexane/acetone （1：1）. Considering solvent- and time-consumption, level of automation, and environmental risk, accelerated solvent extraction with hexane/acetone （1：1） was better than the other extraction techniques.