Toxicity of carbaryl,diquat dibromide,and fluoranthene,individually and in mixture,to larval grass shrimp,Palaemonetes pugio

This study examined the toxicity of two pesticides (carbaryl and diquat dibromide) and one polycyclic aromatic hydrocarbon (fluoranthene), both singly and in mixture, to grass shrimp larvae (Palaemonetes pugio). These three chemicals are all present in coastal environments and can easily enter estuarine ecosystems. Fluoranthene was the most toxic chemical with a 96-h LC₅₀ value of 32.45 μ g/L, followed by carbaryl (43.02 μ g/L) and diquat dibromide (1624 μ g/L). In the chemical mixture tests, the binary carbaryl/diquat dibromide mixture and the ternary carbaryl/diquat dibromide/fluoranthene mixture had additive results.     

碳源对工业污染场地土壤中HCHs和DDTs降解的促进作用

我国对有机氯农药的大量需求使得在农药生产、加工和分装等过程中造成了许多城镇中存在有机氯农药污染场地,限制了土地的后续开发利用.本研究选取3种类型的碳源组成有机修复剂A、B、C,添加到受有机氯工业污染场地土壤中进行微生物降解试验,并对比了3种修复剂的效果.试验过程中,反应体系水分含量为50％,添加零价金属调节氧化还原电位,采用好氧/厌氧交替循环方式进行生物降解.实验结果表明:3种修复剂对HCHs和DDTs的降解都有显著促进作用.与DDTs相比,HCHs较易降解.90 d内,添加修复剂(A、B、C)的处理中∑HCH的浓度分别从73.37~85.71 mg·kg^-1降解到了15.88~38.21 mg·kg^-1.与未添加修复剂的对照相比较,∑HCH的降解率提高了19%~52%,90 d内,ΣHCH的降解率最高可达81%.添加修复剂(A、B、C)的处理中ΣDDT的浓度分别从91.68~119.79 mg·kg^-1降解到了45.1~60.7 mg·kg^-1,相对未添加修复剂的对照试验,∑DDT的降解率提高了39%~45%,30 d内∑DDT的降解率最高可达到51%,但30 d后降解效率无明显增加.就不同类型碳源的促进作用来看,C/N最高,而含水率最低的修复剂B的效果最好,而C/N比最低而含水率最高的修复剂A效果最差.     

有机氯农药污染土壤的Fenton氧化修复研究

研究了Fenton氧化对某实际有机氯农药污染场地土壤的修复效果。结果显示:Fenton氧化能够快速有效地降解污染土壤中的六氯和DDTs。当Fe2+浓度为80 mmol/L,Fe2+与H2O2的摩尔浓度比为1∶5,水土比10∶1时,反应6 h,土壤中六氯和总DDT的去除率分别为:96.7%和78.2%。每方土的修复成本估算为951元。     

青海省西宁市和天峻县大气颗粒物中有机氯农药和类二噁英多氯联苯的水平与分布

本研究测定了青海省西宁市与海西蒙古族藏族自治州天峻县夏、冬两季大气颗粒物中有机氯农药(OCPs)和类二噁英多氯联苯(DL-PCBs)的浓度水平.结果表明,青海省大气颗粒物中OCPs主要为DDTs、HCHs.西宁市DDTs和HCHs的平均水平分别为:35 pg·m-3、5.9 pg·m-3(夏季)和93 pg·m-3、11 pg·m-3(冬季),天峻县DDTs和HCHs的平均水平分别为:83pg·m-3、6.4 pg·m-3(夏季)和28 pg·m-3、6.7 pg·m-3(冬季).与亚洲其它地区相比,青海省大气颗粒物中OCPs处于较低水平.西宁市大气颗粒物中DL-PCBs的平均水平分别为:0.52 pg·m-3(夏季),0.99 pg·m-3(冬季),天峻县为:0.58 pg·m-3(夏季)、0.52 pg·m-3(冬季).西宁市夏、冬两季OCPs的平均水平均大于天峻县,而两地DL-PCBs的平均水平相当.本研究中高原地区DL-PCBs的分布特点及变化规律与极地地区的研究相比存在一定的相似性,而DDTs和HCHs则存在差异性.     

Air pollution and young children's inhalation exposure to organophosphorus pesticide in an agricultural community in Japan

Assessment of airborne organophosphorus pesticides in houses of young children (1-6 years old) and childcare facilities was conducted following pesticide applications in an agricultural community in Japan. Trichlorfon and fenitrothion, applied in two separate periods, were frequently detected from outdoor and indoor air. Dichlorvos, the primary degradation product of trichlorfon, was also detected after the application of trichlorfon. Both the outdoors and indoor concentration of applied pesticide were shown to increase with decreasing distance from the pesticide-applied farm. Indoor concentration of these pesticides significantly correlated with outdoor concentration (p=0.001 for trichlorfon and p=0.001 for fenitrothion), indicating infiltration of applied pesticide inside. Ratio of indoor to outdoor concentration (I/O ratio) of fenitrothion was higher for houses with windows open during the application than those with closed windows (median value: 0.74 vs. 0.16, p=0.003). However, a similar trend was not observed for trichlorfon as well as dichlorvos in the first period. Dichlorvos was found to have a higher I/O ratio than trichlorfon during the period, and clear correlation between indoor concentrations of dichlorvos and those of trichlorfon suggested increased decomposition of trichlorfon in the indoor environment. Daily inhalation exposure estimated by using the fixed measurement data and time-activity questionnaire ranged from 0 to 35 ng/kg/day for trichlorfon, from 0 to 26 ng/kg/day for dichlorvos, and from 0 to 44 ng/kg/day for fenitrothion. Median inhalation exposure from indoor air accounted for 74%, 86.3%, and 45% of the daily inhalation exposure, respectively. For kindergarteners or nursery school children, inhalation exposure at childcare facilities was comparable with or more than that at home, indicating that pollution level at childcare facilities had potential of high impact on children's exposure. Estimated daily inhalation exposures were inversely correlated to the proximity of their activity location to the pesticide-applied farm.     

有机磷农药对蛋白核小球藻的毒性相互作用研究

水体中农药复合污染产生的毒性效应具有潜在风险。为系统考察有机磷农药(OPs)混合物对淡水生态系统中绿藻的联合毒性效应,以马拉硫磷(MIT)、敌敌畏(DDVP)、敌百虫(TRC)、乐果(DIT)和氧乐果(OMT)等5种OPs作为混合物组分,运用直接均分射线法设计9组二元混合物体系共45条混合物射线。利用96孔微板测定5种OPs及其二元混合物对蛋白核小球藻(C. pyrenoidosa)的生长抑制毒性,通过基于置信区间的组合指数法分析混合物的联合毒性及毒性相互作用。结果表明,以p EC50为毒性指标,5种OPs对C. pyrenoidosa的毒性大小顺序为:TRCMITDDVPOMTDIT,OPs对C. pyrenoidosa的毒性大小受其中心磷原子的电正性影响;因混合组分的不同,部分OPs混合物对C. pyrenoidosa的联合毒性依赖于组分浓度比; OPs混合物对C. pyrenoidosa的毒性相互作用以加和为主,部分发生拮抗作用,发生拮抗作用的混合体系具有低效应区域呈加和作用,高效应区域呈拮抗作用的规律;与MIT混合的体系均有发生拮抗作用,且依赖于MIT浓度,MIT浓度比例越高,拮抗作用越强,OPs混合物的毒性相互作用与组分浓度比相关; OPs混合物的毒性相互作用组分浓度比依赖性与其联合毒性的组分浓度比依赖性规律不相关。     

Toxicity of pesticides toward human immune cells U-937 and HL-60

Abstract

The industrialization of the agricultural sector has significantly increased the use of chemicals such as pesticides. Therefore, exposure to them is unavoidable, which makes it necessary to assess their safety for humans at actual exposure doses. This paper aims to determine toxicity of three types of pesticides toward human immune cells (HL-60 and U-937): glyphosate (GLY), deltamethrin (DEL), and chlorothalonil (CHL). Cell viability, membrane integrity, inflammation induction, and antioxidant activity were evaluated to determine differences in cellular response to the tested plant protection agents. In experimental models, all tested substances caused increased mortality of cells after only 24?h. Cell membrane damage was recorded under DEL and CHL influences. The largest disintegration of the cell membrane was due to the action of 100?μg/mL DEL for U-937 and CHL at 1?μg/mL for HL-60. GLY at a concentration of 3,600?μg/mL caused significant peroxidation of U-937 cells’ lipids. CHL-induced inflammation in both types of cells tested. DEL and GLY also induced antioxidant activity in cells. These results lead to the conclusion that the tested pesticides act cytotoxically to the cells of the human immune system in doses to which both farmers and consumers are exposed.     

前驱物结晶体升华成膜法制备TiO2薄膜及其光催化性研究

采用“前驱物结晶体升华成膜法”工艺，使含钛前驱物结晶体草酸氧钛酸以升华的方式，均匀地在玻璃表面形成前驱物薄膜；经过热处理，制备出外观平整透明的玻璃基TiO2薄膜，其薄膜厚度为80-100nm，粒度≤50nm。初步研究了制备条件、薄膜性能和本工艺制备的玻璃基TiO2纳米薄膜对甲基对硫磷的光催化降解性能。     

农药在环境中的水解机理及其影响因子研究进展

农药的水降解与其在环境中的持久性是密切相关的,它是影响农药在环境中的归宿机制的重要依据之一,也是评价农药在水体中残留特性的重要指标。近些年来,国内外不少学者对农药尤其是有机磷、氨基甲酸酯、拟除虫菊酯和磺酰脲类等的水解进行了大量研究,其内容涉及到农药水化学降解机理及其各种因子如pH值、温度和黏土矿物等对农药水解的影响等,并取得了很多新的进展。但是所有这些研究主要集中于实验室内,而对其自然环境中各因子的贡献及其水解机制的了解则相对较少。今后应加强农药在自然条件下的水解动力学与机理以及黏土矿物和腐殖酸对农药在水体中的催化水解研究,以更好地评价农药在环境中的行为与归宿,为农药的合理使用提高科学依据。     

气相色谱法测定蔬菜中多种有机磷农药

探讨同时测定蔬菜中多种有机磷农药残留量的方法.蔬菜样品经前处理后用气相色谱仪测定甲胺磷、敌敌畏、乙酸甲胺磷、氧化乐果、甲拌磷、乐果、马拉硫磷和对硫磷等8 种有机磷农药残留量,测定了方法的回收率和精密度,分析了干扰情况.上述8 种农药的平均回收率分别为99.0%,96.0%,130.4%,101.3%,95.9%,99.4%,92.4%,91.0%,变异系数分别为6.91%,6.09%,9.23%,9.63%,9.18%,7.01%,6.82%,7.50%.该方法操作简便,回收率和精密度较好,干扰少.