Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

Toxicities were assessed for a pyrethroid (cypermethrin) and an organophosphate insecticide (chlorpyrifos) individually and in combination. A series of tests were conducted on di erent responses (acute, chronic, behavioral) of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant e ect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.     

岩溶地下河系统中有机氯的分布特征与来源分析

选取重庆老龙洞、青木关岩溶地下河为研究对象,采用气相色谱仪-微池电子捕获检测器(GC-μECD)分析两条地下河水体中21种有机氯农药(OCPs)的浓度.结果表明,南山地下河中六六六(HCHs)和艾氏剂类化合物(ALDs)是主要检出物,青木关地下河中HCHs和甲氧滴滴涕是主要检出物.南山、青木关地下河中均未检出o,p'-DDE、p,p'-DDE、o,p'-DDD,同时,青木关地下河还未检出o,p'-DDT、狄氏剂,其余OCPs在两条地下河中检出率高达100%.青木关地下河中OCPs浓度范围为145~278 ng·L-1之间,平均值为213 ng·L-1;南山老龙洞地下河中OCPs浓度介于17.7~40.8 ng·L-1之间,平均值为32.7ng·L-1.两条地下河中各OCPs组分表现为地下河出口大于入口.通过对OCPs污染来源分析,发现两地下河流域滴滴涕(DDTs)主要来自于历史上工业DDTs输入,氯丹主要来自于大气沉降.六六六(HCHs)主要来源是林丹的输入,南山地下河属于历史污染,青木关地下河上游的甘家槽有新的HCHs输入.与国内外其他各水体相比,南山地下河水体中HCHs、DDTs浓度处于低水平;青木关下河处于中等偏高水平.结合中外用水卫生标准,发现南山地下河和青木关地下河未超过饮水安全标准.青木关应禁止农田施用有机氯农药,保护地下河生态环境.     

液液萃取-气相色谱法测定地表水中17种有机氯农药研究

建立了二氯甲烷液液萃取-气相色谱法同时测定地表水中17种有机氯农药的方法。标准曲线线性良好,17种化合物的相关系数R2均大于0.999。当取样量为200 mL时,方法检出限在0.015μg/L~0.062μg/L之间。以超纯水样品进行基质加标实验,重复测定6次的相对标准偏差为1.2%~6.2%,平均加标回收率为72.8%~93.5%。方法简单快捷,精密度良好,准确性高,适用于地表水中痕量有机氯农药的测定。     

毛细管气相色谱法测定烟草中有机氯农药残留

研究了烟草中六六六及滴滴涕异构体含量的气相色谱分析方法.样品以石油醚 丙酮在索氏提取器中提取,提取液以浓硫酸净化.采用DB-5弹性石英毛细管柱分离样品,GC-ECD检测农药六六六、滴滴涕的残留量.方法的线性范围为2.27×10-13～7.66×10-11g;最小检测量为1.3×10-8～3.0×10-7 μg,加标平均回收率为95.3%～103.3%,RSD为2.8%～4.5%.     

热脱附对有机氯农药污染土壤微生物响应效应

有机氯农药六六六会对土壤中敏感微生物菌群产生毒性效应,导致敏感微生物菌群种类与数量发生变化。该研究针对不同浓度水平下六六六污染土壤和对应异位热脱附修复后的土壤中微生物的响应及变化进行分析,筛选出了可以作为六六六污染土壤指示生物的微生物。以清洁土壤（CK）、不同六六六污染土壤（H1、H2和H3）和修复后土壤（AR）为供试土壤,基于细菌数量和多样性生物学指标,探究不同污染浓度土壤与修复前后土壤中微生物的差异性。结果表明：（1）与CK土壤相比,梯度污染土壤H1、H2和H3中的细菌数量比CK分别降低95.31%、94.17%、94.06%(P<0.05),AR中细菌数量有所恢复,但显著低于CK,低98.86%(P<0.05);(2)清洁土壤、污染土壤和修复后土壤的细菌多样性存在显著差异,在H3土壤中,特征菌门-变形菌门和特征菌属-假单胞菌属富集明显,占比分别达到99.43%和97.97%,其他物种占比不到1%,AR中微生物的物种组成相比H3有了一定的恢复,群落组成的多样性增加,但是短期内仍比清洁土壤群落多样性低;（3）清洁土壤中Methylomirabilota、硝化螺旋菌门和浮霉...     

玉米浸泡液制备苏云金杆菌生物杀虫剂的影响因素研究

以玉米淀粉生产过程中的浸泡液为培养基,摇瓶发酵培养苏云金杆菌生物杀虫剂,通过一系列单因子试验,考察了不同培养条件(种子液的种龄、接种量、浸泡液的含固率、初始pH值、摇床转速、发酵温度及发酵时间)对苏云金杆菌在玉米浸泡液中的生长(菌数增长与芽孢形成)以及发酵液的生物毒效的影响.研究表明,在最佳摇瓶培养条件(种子液种龄10 h,接种量2%,浸泡液含固量3%,初始pH值7.0～7.5,摇床转速200 r/min,发酵温度30℃)下发酵48 h,活菌数和活芽孢数分别可达到7.9×108 CFU/mL和5.5×108 CFU/mL,毒力效价为698.0 IU/μL.本试验可为生物农药的工业化生产提供实用参数.     

(汍)汊湖水体和表层沉积物中有机氯农药分布特征

用GC/ECD内标法定量测定了(汍)汉湖水体和表层沉积物中的有机氯农药(OCPs).(汍)汊湖水样和表层沉积物中20种OCPs均有检出.表层沉积物上层中(0～2 cm)的OCPs明显高于下层(2～10 cm),这是(汍)汉湖具有稳定的水动力条件所致.氯丹在表层沉积物中浓度最高,与该化合物在环境中的强稳定性以及在该地区的大量使用有关.表层沉积物样品DCHsO2上层OCPs中o,p'-DDT主要成分,表明近期可能有新的DDTs,特别是含大量o,p'-DDT的三氯杀螨醇的使用.DDD/DDE则显示表层沉积物上层DDTs的降解主要处在厌氧条件下,而下层处在好氧条件下.     

基质固相分散萃取—气相色谱法测定土壤中有机氯农药含量

建立了一种基质固相分散萃取—气相色谱法测定土壤中8种有机氯农药含量的方法,优选了固相分散剂及其用量、洗脱溶剂以及土壤样品与分散剂的质量比.实验结果表明,在弗罗里硅土作为分散剂、正己烷和丙酮(体积比为1:1)为洗脱溶剂、土壤样品与分散剂的质量比为1:3的优化条件下,8种有机氯农药在50～250μg/kg范围内表现出良好的...     

Isolation, characterization and phylogenetic analysis of a bacterial strain capable of degrading acetamiprid

An aerobic bacterium, capable of degrading the new chloronicotine pesticide acetamiprid, was isolated from the sludge of pesticide factory after successive enrichment cultures and named strain FH2 which is a Gram-negative, rod-shaped, obligate aerobic org     

Effects of cyclodextrins on hydrolysis of malathion

Cyclodextrins （CDs）, with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD （RAMEB） and hydroxypropyl β-CD （HP-β-CD）, were tested. It was found that RAMEB could inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35℃. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP- β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25℃, oH 9.0.