~(14)C-丁草胺、~(14)C-毒死蜱和~(14)C-DDT在日本林蛙中的生物学行为(英文)

用同位素示踪技术研究了14 C 丁草胺、14 C 毒死蜱和14 C DDT在日本林蛙 (RanajaponicajaponicaGuenther)中的生物学行为。结果发现 ,14 C 丁草胺、14 C 毒死蜱和14 C DDT在 2 4h后分布到青蛙的各个器官组织 ,并分别以胆囊、小肠、小肠为它们的特异性浓集器官。与胆囊或小肠的14 C放射性活度比较 ,其它器官组织中的要小得多。14C DDT在日本林蛙中较难降解 ,2 4h后DDT母体在肝和脂肪组织中占DDT代谢物的54 6%和 88 4%。青蛙中的14 C 丁草胺、14 C 毒死蜱和14 C DDT可被丙酮提取 ,但三者之间以及在青蛙的器官之间有差异     

肯尼亚水稻土和甘蔗地土壤中~(14)C-六氯苯和~(14)C-滴滴涕的自然消解

氯代持久性有机污染物的农田土壤污染呈现污染浓度低、面积大、新源污染不断输入的特点。农田土壤本身微生物种类丰富,对氯代有机污染物具有较大的降解潜力和未知性。本试验以典型高氯代和低氯代持久性有机污染物——六氯苯(HCB)和滴滴涕(DDT)为研究对象,结合~(14)C同位素示踪技术,研究HCB和DDT在热带水稻土和甘蔗地土壤的矿化现象,同时监测HCB和DDT在两种土壤中的挥发、降解产物以及结合残留。结果表明,经84 d好氧培养,HCB和DDT在两种土壤中的矿化量分别仅为0.14%和3%,低氯代有机污染物DDT的矿化速率显著高于高氯代有机污染物HCB。然而,两种土壤对HCB或DDT的矿化没有显著性差异。HCB或DDT在水稻土中的挥发量略微高于甘蔗地土壤,两种土壤中HCB和DDT的挥发量在0.1%~0.6%之间,表明挥发不是其主要的环境过程。在DDT污染水稻土和甘蔗地土壤中添加1.25%的堆肥增加了DDT在土壤中的矿化与结合残留,减少了DDT的挥发。本研究结果表明土壤在好氧条件下对氯代持久性有机污染物的自然消解能力非常弱,而有机肥的使用有助于土壤中持久性氯代有机污染物的矿化消除。     

DDT引发的争论及启示

本文沿着DDT从1874年合成到将在2020年淘汰的轨迹和趋势,第一次依据历史重大事件并结合SCI文献数量将DDT的发展分为4个历史阶段,着重探讨了这种“万能杀虫剂”带来的3个争论:DDT对人类的健康影响、禁用还是使用DDT、以及如何评价DDT.本文从DDT由人类的“宠儿”变成“弃儿”的历史演变中分析得出了一些启示,并...     

日粮淀粉来源对断奶仔猪内脏器官蛋白质合成率的影响

应用稳定同位素L2-H5苯丙氨酸一次性大剂量(1.5mmol/kg)腹腔注射法,研究了日粮淀粉来源对断奶仔猪内脏器官蛋白质合成率的影响。结果表明,玉米淀粉促进了仔猪内脏器官蛋白质的合成,其蛋白质合成率高于糙米淀粉(P>0.05)和糯米淀粉(P<0.05)。其中十二指肠、空肠、回肠、结肠、胰脏和肝脏的蛋白质合成率分别比糯米的高85.87%、47.47%、37.29%、56.29%、43.55%和17.63%。     

杂交苏丹草(Sorghum bicolor×S.sudanense)修复DDT污染土壤效果研究

采用盆栽试验,研究了杂交苏丹草吸收和富集DDT的规律及其对DDT污染土壤的修复效果。结果表明:①土壤中添加高浓度的DDT,对杂交苏丹草的生物量没有显著影响,说明杂交苏丹草对DDT有耐受能力;②杂交苏丹草对DDT及其主要降解产物都有吸收,在旺盛生长期,植株中DDT的累积速率也较快;③杂交苏丹草根系中DDT及其主要降解产物的浓度是茎叶中相应组分浓度的4.81~10.32倍,质量比在0.57~1.55倍之间;④杂交苏丹草从土壤中吸收DDT占添加量的11.3%,而在其生长期间,土壤中DDT消失量为56.0%。     

堆肥对有机氯农药挥发和降解的效果

选用鸡粪和玉米秸秆为堆肥原料,进行高温好氧堆肥试验,研究了堆肥处理对六六六（HCH）和滴滴涕（DDT）挥发和降解的影响。研究表明,30 d内,堆肥过程的高温和通气条件导致HCH和DDT的挥发比例分别为20.6%、13.8%;扣除堆肥过程中高温和通气等因素对有机氯挥发的影响后,未添加菌剂处理HCH和DDT的降解率分别为37.2%和14.9%,添加菌剂处理HCH和DDT的降解率分别为42.1%和24.2%,与未添加菌剂处理差异显著;α-HCH、δ-HCH的降解率高于β-HCH、γ-HCH,pp'-DDT、op'-DDT的降解率高于pp'-DDD、pp'-DDE。试验结果说明,堆肥过程中高温和通气促使了HCH和DDT向气相中挥发,而该过程的生化反应有助于HCH和DDT等有机氯农药的降解。     

正丙醇与羟丙基-β-环糊精复配对高浓度DDT污染土壤的增效洗脱修复研究

以武汉某高浓度滴滴涕(DDT)污染场地土壤为研究对象,采用正丙醇和羟丙基-β-环糊精(HPCD)为洗脱剂进行相关的洗脱试验,并嵌合升温措施,研究了其对DDT污染场地土壤的洗脱修复效果。试验结果表明,20%正丙醇和50 g L-1HPCD复配、50℃水浴连续洗脱5次,可以使土壤中DDT总量的平均去除率达到96.41%。研究为DDT污染场地土壤的异位增效洗脱技术研发提供了一种有效手段。     

用水生生物摇蚊幼虫监测11种农药

用摇蚊幼虫对4类11种农药进行试验。11种农药为,DDT、环氧七氯、毒死蜱、马拉硫磷、双硫磷、西维因、灭多虫、残杀威、苄氯菊酯、除虫菊酯、灭虫菊。其纯度为93～100%。选用未受污染地区的二龄期摇蚊幼虫作为试验对象,使用容积为50毫升的玻璃缸。每缸放入10只摇蚊幼虫和适量的     

基于稳定同位素和矿质元素的决明子产地特征与溯源判别研究

为了更加精确高效地对中药决明子产区进行判别,本研究采用稳定同位素比质谱(IR-MS)和电感耦合等离子体质谱(ICP-MS)技术分别检测不同产地决明子稳定同位素比值和多种矿质元素含量特征,并结合化学计量学模型主成分分析(PCA)和人工神经网络(ANN)对决明子产地进行判别。方差统计结果表明,在优质产区(浙江新昌)决明子区别于普通产区决明子方面,19种矿质元素含量存在显著差异(P<0.05);PCA分析(同位素+矿物元素)显示,前2个主成分累计方差贡献率为45.23%,且该模型可显著区分道地产区决明子;ANN模型分析对浙江新昌产区的决明子判别正确率高达100%,且产地判别总体正确率高于90%。以上结果表明,稳定同位素比值和矿质元素含量结合化学计量学模型分析可有效判别决明子不同产区。本研究结果为决明子产地溯源提供了一种新的方法。     

稳定同位素和元素指纹分析在白术产地溯源中的应用

为解决道地药材白术的产地溯源问题,本研究采用稳定同位素比质谱仪(EA-IRMS)和电感耦合等离子质谱仪(ICP-MS)测定了6个产地168种白术中δ¹³C、δ¹⁵N、δ²H、δ¹⁸O和δ³⁴S值及41种矿质元素含量,并结合化学计量学对不同产地白术进行鉴别。结果表明,线性判别分析(LDA)可以区分6个产地的白术。基于不同变量共建立7种不同判别模型,其平均交叉验证率分别为:稳定同位与素(88.17%)、矿质元素(98.67%)、常量矿物元素(41.83%)、 痕量矿质元素(99.33%)、稳定同位素与矿物质元素(100%)、稳定同位素与常量矿质元素(91.83%)以及稳定同位素与痕量矿物质(98.83%)。其中,δ¹⁸O、 δ³⁴S值以及Li、Dy、Sm、Er等稀土元素是影响判别的主要因素,主要由产地地理位置、气候条件和土壤类型决定。综上,基于稳定同位素、矿质元素和化学计量学的方法可对不同产地白术进行产地溯源。     

Simplified method for estimation of DDT and hexachlorocyclohexane residues in milk

A procedure that combines acetone-hexane extraction and cleanup by treatment with concentrated sulfuric acid is described for determining DDT and 1,2,3,4,5,6-hexachlorocyclohexane (HCH) residues in milk. Recoveries from samples fortified with 0.004-0.008 ppm of different HCH isomers and 0.01-0.02 ppm DDT and its metabolites ranged from 83.4 to 99.8%. The proposed method is simple and rapid, and does not require the use of costly adsorbents.     

Uptake and phytotransformation of o,p'-DDT and p,p'-DDT by axenically cultivated aquatic plants

The uptake and phytotransformation of o,p'-DDT and p,p'-DDT were investigated in vitro using three axenically cultivated aquatic plants: parrot feather (Myriophyllum aquaticum), duckweed (Spirodela oligorrhiza), and elodea (Elodea canadensis). The decay profile of DDT from the aqueous culture medium followed first-order kinetics for all three plants. During the 6-day incubation period, almost all of the DDT was removed from the medium, and most of it accumulated in or was transformed by these plants. Duckweed demonstrated the greatest potential to transform both DDT isomers; 50-66% was degraded or bound in a nonextractable manner with the plant material after the 6-day incubation. Therefore, duckweed also incorporated less extractable DDT (32-49%) after 6 days than did the other plants. The capacity for phytotransformation/binding by elodea is between that of duckweed and parrot feather; approximately 31-48% of the spiked DDT was degraded or bound to the elodea plant material. o,p'-DDD and p,p'-DDD are the major metabolites in these plants; small amounts of p,p'-DDE were also found in duckweed (7.9%) and elodea (4.6%) after 6 days. Apparently, reduction of the aliphatic chlorine atoms of DDT is the major pathway for this transformation. This study, which provides new information on plant biochemistry as related to pollutant accumulation and phytotransformation, should advance the development of phytoremediation processes.     

利用~(14)C-BHC验证检测六六六农药的方法

利用~(14)C-六六六,验证浓硫酸净化法与国际公认的美国化学家协会方法检测稻米中六六六农药残留量的结果表明,前者平均回收率达90.0％,平均相对标准偏差为8.0％(n=9);后者的回收率88.9％、平均相对标准偏差为3.0％。两种方法统计学上无显著差异,即两种方法有可比性,证实我国沿用已久的浓酸净化法是可行的。     

蔬菜不同部位对DDTs的富集与分配作用

在可控条件下研究了人为污染土壤中DDT类污染物在蔬菜（菠菜和胡萝卜）不同部位的富集与分配规律。结果表明,DDT类污染物在菠菜和胡萝卜叶部和根部均有一定富集,其中菠菜叶面富集量占富集总量的68.6%～92.2%之间;而胡萝卜叶部富集占富集总量的34.9%～41.6%之间。不同DDTs在菠菜和胡萝卜体内的生物富集量呈：p,p＇-DDE〉p,p＇-DDT〉p,p＇-DDD〉o,p＇-DDE〉o,p＇-DDT的规律。DDTs通过不同途径在菠菜和胡萝卜内的生物富集系数表现如下规律：BCF大气－菠菜〉BCF大气－胡萝卜〉BCF土壤－胡萝卜〉BCF土壤－菠菜。不同DDTs在蔬菜体内的生物富集系数表现为：BCFp,p＇-DDE〉BCFo,p＇-DDE〉BCFp,p＇-DDD〉BCFp,p＇-DDT〉BCFo,p＇-DDT。由于DDTs在蔬菜体内富集后,可沿食物链传递和放大,对农产品质量和人体健康构成直接威胁。     

Rapid quantification of proanthocyanidins (condensed tannins) with a continuous flow analyzer

Proanthocyanidins (condensed tannins) frequently need to be quantified in large numbers of samples in food, plant, and environmental studies. An automated colorimetric method to quantify proanthocyanidins with sulfuric acid (H(2)SO(4)) was therefore developed for use in a continuous flow analyzer. Assay conditions were optimized using 50% methanol extracts of paper birch, sugar maple, and quaking aspen leaves. Short extraction times and centrifugation of samples prevented proanthocyanidin degradation that otherwise occurred in 50% methanol extracts of aspen leaves. Extraction of birch and maple proanthocyanidins with 50% methanol was comparable to or better than that with 70% acetone. Proanthocyanidin levels in aspen were lower when extracted with aqueous methanol, but relative differences among samples were consistent with those found in aqueous acetone extracts. Results from the automated sulfuric acid assay were highly correlated with those of the conventional BuOH-HCl method for proanthocyanidins and, except for birch, with the Folin--Denis assay for total phenolics. This new technique significantly improves assay processing rate and repeatability compared to conventional colorimetric proanthocyanidin assays.     

DDT and HCH Residues in Basmati Rice (Oryza sativa) Cultivated in Dehradun (India)

Organochlorine pesticides were used earlier for agricultureproduction. Their residues may still be present in soil and mayaccumulate in food crops, posing potential health problems to consumers. DDT, HCH, their isomers and metabolites were analyzedin samples of soil and rice plants collected from ten differentvillages of a well-known Basmati rice growing area in Dehradun.Residues of both pesticides were found in all samples ofsoil and different parts of rice plants except for a few grainsamples. Maximum residue was observed in husk and minimum ingrains. The average concentration of DDT in soil ranged from0.013 to 0.238 ppm. p,p′-DDE was the major metabolite (>63%). Theaverage concentration of DDT in rice grain varied from 0.002 to 0.040 ppm. o,p′-DDT was the main isomer (>93%). Theaverage concentration of HCH in soil ranged from 0.122 to 0.638 ppm. β-HCH was the predominant (43%) isomerfollowed by α-HCH (21%). The average HCH concentrationin rice grain ranged between 0.013 and 0.113 ppm. All four isomers were present in grains. The levels of DDT and CHCin grains were similar in magnitude as those from differentIndian states, but well below the maximum residue limit of 0.1 ppm for DDT and 0.05 ppm for HCH prescribed by the Government ofIndia and WHO/FAO. As such, the pesticide residue levels in thisexport commodity are not of hazardous nature.     

AQDS加速红壤性水稻土中DDT厌氧脱氯效应研究

电子供体基质和电子穿梭体对电子转移过程有重要影响,进而可能影响厌氧反应体系中2,2-双(4-氯苯基)-1,1,1-三氯乙烷(DDT)还原脱氯降解。为了阐明电子供体基质正丁酸与电子穿梭体蒽醌-2,6-二磺酸盐(AQDS)对红壤性水稻土中DDT还原脱氯效果的影响,本研究采用厌氧土壤培养试验并设定以下5个处理:1灭菌对照,2对照,3正丁酸,4AQDS,5正丁酸+AQDS。结果表明,厌氧培养20 d后,土壤中DDT可提取态残留量减少了85.2%~96.3%。DDT厌氧脱氯降解的主要产物为2,2-双(4-氯苯基)-1,1-二氯乙烷DDD。添加正丁酸在培养前8d显著提高产CH4速率,而对DDT脱氯降解无显著促进作用,第8天之后,随着产CH4速率降低,添加正丁酸处理的DDT脱氯速率逐渐升高。添加AQDS显著增强土壤还原性并加速三价铁氧化物还原生成电子供体二价铁,进而显著促进DDT还原脱氯降解。同时添加正丁酸和AQDS对促进DDT还原脱氯的效果最佳,但是正丁酸和AQDS对加速DDT还原脱氯无显著交互作用。本研究结果对于制定DDT污染土壤的高效原位修复技术方案具有指导意义。     

Improved detection of sugar addition to maple syrup using malic acid as internal standard and in 13C isotope ratio mass spectrometry (IRMS)

Stable carbon isotope ratio mass spectrometry (delta13C IRMS) was used to detect maple syrup adulteration by exogenous sugar addition (beet and cane sugar). Malic acid present in maple syrup is proposed as an isotopic internal standard to improve actual adulteration detection levels. A lead precipitation method has been modified to isolate quantitatively malic acid from maple syrup using preparative reversed-phase liquid chromatography. The stable carbon isotopic ratio of malic acid isolated from this procedure shows an excellent accuracy and repeatability of 0.01 and 0.1 per thousand respectively, confirming that the modified lead precipitation method is an isotopic fractionation-free process. A new approach is proposed to detect adulteration based on the correlation existing between the delta13Cmalic acid and the delta13Csugars-delta13Cmalic acid (r = 0.704). This technique has been tested on a set of 56 authentic maple syrup samples. Additionally, authentic samples were spiked with exogeneous sugars. The mean theoretical detection level was statistically lowered using this technique in comparison with the usual two-standard deviation approach, especially when maple syrup is adulterated with beet sugar : 24 +/- 12% of adulteration detection versus 48 +/- 20% (t-test, p = 7.3 x 10-15). The method was also applied to published data for pineapple juices and honey with the same improvement.     

Organochloride insecticide residues in air in Delhi,India

Regular monitoring of air at three different sites, namely, Netaji Nagar, Moti Nagar and Town Hall in the metropolitan city of Delhi, India from June, 1980 to May, 1982 revealed varying levels of residues of DDT and HCH. The concentration of total DDT residues varied from 4 to 232 ng m^?3 with an average of 60 ng m^?3. Total HCH ranged from 0 to 21797 ng m^?3 with an average of 438 ng m^?3. Comparatively higher levels of total DDT (73 ng M^?3) were detected at Moti Nagar, the site near a DDT factory. The total HCH was highest at Town Hall (931 ng m^?3). Normally, higher quantities of the residues of DDT and HCH were detected during October to December. The insecticide residues consisted mainly of p, p′-DDT, p, p′-DDE, o, p′-DDT and p, p′-DDD, α- and γ-HCH. Only p, p′-DDT and p, p′-DDE were detected in all the samples and accounted for the bulk of total DDT. The HCH residues were mainly due to the α-isomer. Generally the concentration of HCH was higher than DDT in the air samples collected during the survey.     

A new LC/MS-method for the quantitation of acrylamide based on a stable isotope dilution assay and derivatization with 2-mercaptobenzoic acid. Comparison with two GC/MS methods

Acrylamide (AA) was found to form a stable thioether in reasonable yields (45-50%) when reacted with 2-mercaptobenzoic acid at 20 degrees C for 3 h. On the basis of this finding and using [(13)C(3)]-acrylamide as the internal standard, a sensitive and selective new stable isotope dilution analysis for AA quantitation in food samples was developed based on single stage LC/MS. Comparison of the quantitative results obtained by applying the new method to potato chips, crispbread or butter cookies with data obtained by two stable isotope dilution analysis, using direct measurement of AA by GC/MS, but differing in the workup procedure, revealed detection limits in the same order of magnitude (6.6 microg/kg). Quantitative data obtained by application of the three methods on the same samples of potato chips or cookies, respectively, were also in very good agreement. Quantitation of AA in crispbreads treated with an amylase/protease mixture did not show increased AA levels, thereby indicating that inclusion of AA in starch/protein gels is not very probable during breadmaking.