养殖水体中敌百虫的残留检测和降解分析

对养殖水体和不同pH值条件下,采用HLB小柱固相萃取处理水样,进行敌百虫残留的检测和降解分析。检测简化了前处理方法,最低检出限为0.1μg/L,回收率达到80%～110%。配制的250 mg/L、500 mg/L两种浓度的敌百虫水溶液,在中性的条件下24 h降解了15%,碱性条件下24 h降解了100%,pH值越高降解越快。在养殖河蟹的水体中,高浓度的敌百虫溶液比低浓度敌百虫溶液降解。     

敌百虫对泥鳅、鲤鱼的急性毒性试验

以渔用双效速溶敌百虫为试验药物,对泥鳅、鲤鱼进行急性毒性试验。在不同的浓度组药物作用下,泥鳅1mg/L、2mg/L、4mg/L、8mg/L、16mg/L试验,半致死浓度3.4mg/L,安全浓度0.34mg/L;鲤鱼0.1mg/L、0.2mg/L、0.5mg/L、1mg/L、2mg/L、5mg/L试验,半致死浓度1.5mg/L,安全浓度0.15mg/L。每间隔2h观察、记录试验鱼的自然状况、死亡尾数、体色、呼吸状况及活动状况;同时,测定水体温度、气温、pH值及水体溶氧量。试验验证了敌百虫对泥鳅、鲤鱼的毒副作用较强,敌百虫对泥鳅的最低致死浓度为2mg/L,对鲤鱼的最低致死浓度为1mg/L,说明泥鳅比鲤鱼的抗药性强。中毒症状主要表现为焦躁不安、上下窜动、呼吸减弱、鱼体弯曲、翻肚且倒挂于水中的神经中毒现象;检查可见,鳃丝淤血、鳍部充血、眼球突出、嘴大张。     

敌百虫对鲫鱼的急性毒性研究

通过96h急性毒性实验敌百虫对鲫鱼的LC50为63.97mg/L,95%可信限为1.81±0.048 mg/L,95%可信区间为57.81～72.11 mg/L.分别选取1/2、1/4、1/8及1/16LC50为染毒浓度,于实验开始后24、48、72及96h采样分析,结果表明随着暴露时间的延长,各浓度组实验鱼血浆胆碱酯酶的活性均有一定的升高,但各浓度组间没有表现出明显的区别.实验剂量下的敌百虫对鲫鱼血浆CST活性有一定的影响,呈现出较为明显的先扬后抑的结果.1/2LC50实验组血浆CAT在实验进行至96h活性明显高于对照组,而其他剂量组在实验期间CAT活性没有明显的改变.本实验中敌百虫对鲫鱼的遗传性在微核率上未表现出差异,但高浓度核异常率在实验24、48h明显高于对照组.     

敌百虫在异育银鲫体内富集与消除规律

在(20±2)℃的水温条件下,将异育银鲫(Carassais auratus gibebio)分别浸浴于0.2 mg/L、0.5 mg/L浓度(理论浓度)的敌百虫水溶液进行7 d富集试验,第8天起隔天换清水进行消除试验,研究了敌百虫在异育银鲫体内的富集与消除规律。结果显示:鳃组织中敌百虫富集浓度最高,且给药后2 h时就接近水体中药物浓度,7 d内一直保持在相对较平稳的浓度水平;肝胰脏、肌肉组织中敌百虫浓度随时间延长逐渐增高,肝胰脏组织富集浓度略高于肌肉组织。消除试验1 d后鳃组织中敌百虫浓度迅速下降,消除了91.4%,以后消除速度趋缓,至第5~7天未检出敌百虫;肝胰脏、肌肉组织中敌百虫浓度随试验时间延长逐渐降低,且分别在消除试验的第5天、第7天未检出敌百虫,肝胰脏组织中敌百虫消除速度比肌肉组织中快。     

几种常用水产药物对虹鳟的毒性试验

本文研究了高锰酸钾、孔雀石绿、敌百虫、食盐等对虹鳟鱼种的毒性。它们的安全浓度依次为0.029pm、0.019ppm、0.05ppm。实验后24、48、96小时,虹鳟对各药物的半致死浓度TL_m分别为:高锰酸钾1.65ppm、1.56ppm、0.29ppm;孔雀石绿0.33ppm、0.33ppm、0.19ppm;敌百虫3.7ppm、1.6pm、0.5ppm。作者还对三种药物对虹鳟的毒性作用特点进行了讨论。     

敌百虫除鱼鲺效果好

<正> 1995年7月,丰润县任各庄镇孙家庄鱼种场购进鲤鱼夏花6万尾。放养20d后,发现鱼种急剧狂游和跳跃,经检查,大部分鱼种患有鲺病,有的寄生的鲺多达3～4只。经用0.5ppm90％晶体敌百虫全池     

毛腹虫对家鱼孵化危害的初步研究

首次报道了仙女虫科的毛腹虫对家鱼孵化的危害，并进行了防治初步试验，毛腹虫喜生于偏碱性水体，将孵化用水pH值变为弱酸性，可使虫体消失，5-20ppm的高锰酸钾、0.2-0.7ppm的硫酸铜、0.2-0.5ppm的90%敌百虫对毛腹虫无杀灭效果。     

敌百虫、食盐混用效果好

在鱼病防治中敌百虫、食盐单独使用已十分普及，两者若混用，又有其独特疗效。我场一口面积为九亩的池塘，八月中旬草鱼患严重的鳃蛆病和赤皮病，每天死亡10～20尾草鱼。我们试用敌百虫和食盐合剂治疗，三天后鱼即停止死亡。具体用法是敌百虫药物浓度为0．3～0．5ppm，食盐以敌百虫总量的5～29倍计算，两者分别用适量的池水溶化后再行混合，兑水全池泼洒．此法经本人多次试验证明是可行的，     

使用敌百虫的注意点

一、使用敌百虫前,应先准确计算好水体体积,以达到药到病除目的。使用时,要先将成块敌百虫打碎、充分溶解后,再在鱼池泼洒,以免鱼误食其颗粒而中毒死亡。施     

在轮虫培养中用敌百虫杀灭桡足类的试验

针对鱼、虾、蟹人工苗种生产中经常遇到的由于轮虫中混杂桡足类导致育苗失败的实际情况,探讨利用轮虫和桡足类对晶体敌百虫忍耐性的差异,在不影响轮虫生长、繁殖的情况下彻底清除桡足类的方法。结果表明:轮虫和桡足类对敌百虫的忍耐性有较大的差异,轮虫和桡足类的96h敌百虫安全浓度分别为2.0mg/L和0.2mg/L;致死浓度分别为3.0mg/L(96h)和0.4 mg/L(72h);在敌百虫添加浓度0.5~2.0mg/L条件下,敌百虫对轮虫繁殖率的影响随添加浓度加大而增加,但这一影响是可逆的,一般在2~3d后即可恢复正常。在苗种生产实际中,将敌百虫处理浓度定为1.0~1.5mg/L较为适宜。     

敌百虫对中华绒螯蟹幼体的毒性研究

采用实验室小型水族箱,每组设1个空白对照、2个平行组,研究敌百虫对中华绒螯蟹不同生长期幼体的急性毒性。结果表明:中华绒螯蟹Ⅱ期蚤状幼体(Z2)24 h和48 h LC50分别为0.0052和0.0045 mg/L,安全浓度为0.00101 mg/L;Ⅲ期蚤状幼体(Z3)24 h和48 h LC50分别为0.0061和0.0051 mg/L,安全浓度为0.00262 mg/L;Ⅳ期蚤状幼体(Z4)24 h和48 h LC50分别为0.0053和0.0039 mg/L,安全浓度为0.00063mg/L;大眼幼体(M)24 h和48 h LC50分别为0.0104和0.0087 mg/L,安全浓度为0.00202 mg/L。     

Degradation of trichlorfon to dichlorvos in seawater: A preliminary report

A HPLC method to measure the degradation of trichlorfon to dichlorvos in seawater at different temperatures is presented. Seawater containing the trichlorfon and dichlorvos was injected directly into the HPLC system without any pretreatment. Detection was by UV at 205 nm. The sensitivity for trichlorfon was 1 ppm, and for dichlorvos 0.02 ppm.     

Effect of trichlorfon on oxidative stress and hepatocyte apoptosis of Carassius auratus gibelio in vivo

To investigate the effect of trichlorfon on oxidative stress and hepatocyte apoptosis of Carassius auratus gibelio in vivo, the fish were exposed to 0, 0.5, 1.0, 2.0 and 4.0?mg?l(-1) trichlorfon concentrations for 30?days. At the end of the experiment, plasm antioxidant activities, hepatic total nitric oxide synthase (T-NOS) activity, xanthine oxidase (XOD) activity and hepatocyte apoptosis rate were analyzed. The results showed hepatic T-NOS activities, XOD activities and hepatocyte apoptosis rate were increased with trichlorfon concentration increase. The hepatic MDA content was increased significantly at 4.0?mg?l(-1) trichlorfon treatment. The disturbance of antioxidative balance was observed based on the monitoring of the plasm superoxide dismutase (SOD), catalase (CAT) activities and vitamin E levels. The current study revealed that trichlorfon influenced fish plasma antioxidative status, caused lipid peroxidation (LPO) then resulted in hepatocytes apoptosis.     

The extracts of Angelica sinensis restore the digestive and absorptive capacity through improving antioxidant status in digestive organs of fish treated with trichlorfon

Firstly, a linoleic acid emulsion and fish hepatopancreas homogenate were incubated with ethoxyquin and the extracts of Angelica sinensis. The results demonstrated that ethoxyquin showed the strongest protective effects against lipid oxidation of all of the examined compounds (p < 0.05). However, ethyl acetate extract of Angelica sinensis at high concentrations showed a stronger effect on lipid oxidation than that of ethoxyquin (p < 0.05). Next, seven experimental diets that contained 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 g/kg of ethyl acetate extract of Angelica sinensis were fed to seven groups of carp (Cyprinus carpio var. Jian) respectively. After 60 days, carp were exposed to 2.4 mg trichlorfon/L in water for 4 days. The results displayed that trichlorfon exposure increased the contents of malonaldehyde and protein carbonyl in digestive organs and the activities of glutamate‐oxaloacetate and glutamate‐pyruvate transaminase in plasma, and decreased feed intake, the level of reduced glutathione, and the activities of trypsin, chymotrypsin, lipase, alpha‐amylase, Na⁺,K⁺‐ATPase, alkaline phosphatase, antisuperoxide anion, antihydroxyl radical, superoxide dismutase, glutathione reductase, and glutathione S‐transferase in digestive organs of carp (p < 0.05). Moreover, the dietary ethyl acetate extract of Angelica sinensis prevented the decrease in the above parameters in carp treated with trichlorfon (p < 0.05). These results revealed that the dietary ethyl acetate extract of Angelica sinensis could quench the trichlorfon‐induced structural and functional damage by improving the antioxidative capacity of the digestive organs of fish. Therefore, the extract of Angelica sinensis could be used as an inhibitor of trichlorfon stress in fish.     

Effects of trichlorfon, fenthion, and diflubenzuron on the zooplankton community and on production of reciprocal-cross hybrid striped bass fry in culture ponds

The application of trichlorfon, diflubenzuron, or fenthion to fertilized culture ponds stocked with 5-day-old, reciprocal-cross, hybrid striped bass fry resulted in an initial reduction in the concentration of rotifers and longer-term alteration of zooplankton successional stages, including changes in concentrations of rotifers, cladocerans, and copepods. Culture ponds without applied chemicals had the highest concentrations of small rotifers when fry were stocked, followed by high concentrations of cladocerans, copepod nauplii, and adult copepods. Fry survival in untreated ponds was higher than in chemically-treated ponds. Initial high concentrations of copepods in some ponds corresponded with low fry survival. Untreated ponds that were filled at the time of broodfish spawning, and stocked with fry 5 days later, had the highest fry survival rates, corresponding with peak rotifer concentrations, followed by a typical zooplankton succession.     

Effects of an organophosphorus insecticide,trichlorfon, on hematological parameters of the giant freshwater prawn,Macrobrachium rosenbergii (de Man)

Hemolymph osmolality, ion concentration, acid–base balance, and immune parameters in Macrobrachium rosenbergii (15–20 g) were measured after 8 days of exposure to 0–0.3 mg l⁻¹ trichlorfon. A significant depression in hemolymph osmolality and Cl⁻¹ contents were observed with exposure to 0.3 mg l⁻¹ trichlorfon. Similarly, hemolymph pH, HCO₃⁻, and TCO₂ decreased significantly when prawns were exposed to concentration of greater than 0.2, 0.1, and 0.1 mg l⁻¹ trichlorfon, respectively. A notable increase in the hemolymph pCO₂ was observed with 0.3 mg l⁻¹ trichlorfon. However, no significant differences in hemolymph oxyhemocyanin or protein levels were observed among prawns with 0–0.3 mg l⁻¹ trichlorfon. These findings may have resulted from histological changes in the respiratory epithelium and/or the inhibitory action of the nervous system of respiration. Phenoloxidase activity in the hemocytes of prawns decreased significantly with exposure to greater than 0.2 mg l⁻¹ trichlorfon. This indicates that trichlorfon reduces the immune ability of M. rosenbergii.