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毒氟磷是我国自主创制的新型植物抗病毒剂,研究毒氟磷的环境行为和归趋对科学评价其环境风险具有重要意义。本试验采用14C同位素示踪技术,以[噻唑基-2-14C]-毒氟磷为示踪剂,研究了毒氟磷在A和B两种水-沉积物系统中的好氧降解动态以及残留转化规律。结果表明,毒氟磷母体在两种水-沉积物系统中的水相消散和降解均符合一级动力学模型,其水相消散半减期分别为7.23 d (A)和13.86 d (B),在水-沉积物整个系统中的母体降解半减期则分别为121.60 d (A)和65.39 d (B)。毒氟磷在供试水-沉积物系统中的残留转化规律存在显著差异,培养结束时(培养时间为100 d),可提态残留在A和B系统中分别占放射性引入量的77.41%和43.71%,矿化量分别占放射性引入量的1.11%和2.83%,结合态残留分别占放射性引入量的24.11%和49.25%;较高的降解率和阳离子交换量是毒氟磷及其代谢产物在B系统中更易形成结合残留的主要原因。本研究结果为科学评价毒氟磷在水-沉积物系统中的安全性提供了基础数据和科学依据。 相似文献
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为深入了解毒氟磷在植物体内的残留代谢规律,以大豆为研究对象,利用14C示踪法研究了[苄基-14C]-毒氟磷在大豆中的残留分布特征及代谢产物动态变化规律。结果表明,施药后毒氟磷主要残留在大豆受施叶上,在豆叶中毒氟磷母体的半衰期为15.32 d,施药后代谢产物的残留浓度均随时间推移而不断增加;至施药20 d时,叶片上毒氟磷母体的残留浓度为6.960 mg·kg-1, 占总放射性活度的53.443%;代谢产物M4、M3、M1+M2的残留浓度分别为3.838、2.431、1.464 mg·kg-1; 收获时,可食豆子中残留物含量小于总放射性残留的0.3%,其代谢产物组成与叶中相同;母体及M4的相对含量分别为51.932%和20.301%,且两者残留浓度均大于0.050 mg·kg-1。本试验为客观评价毒氟磷的安全性提供了重要的代谢数据。 相似文献
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为探究茶树不同叶位的传统稳定同位素分布及其随时间的变化特征,本研究以龙井43#品种茶树为研究对象,采用元素分析-同位素比值质谱仪(EA-IRMS)对不同叶位叶片的碳同位素(δ13C)、氮同位素(δ15N)、氢同位素(δ2H)和氧同位素(δ18O)进行分析。结果表明,随叶位自上向下递增,叶片中δ13C、 δ15N和δ2H显著贫化,而δ18O呈现相对较弱的贫化,且第2~第5叶位叶片的同位素比值最高(21.0‰~25.0‰),相邻叶位的同位素分馏系数差异不大。此外,随着采样时间的变化和环境气候影响,前三叶位叶片的δ13C和δ15N总体呈现富集特征,而δ2H和δ18O出现先贫化后富集的变化特征。本研究结果为探究茶树不同叶位茶叶传统稳定同位素的分布提供了数据支撑,也为研究茶叶分馏机制和数据库构建奠定了基础。 相似文献
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为探究稳定同位素在黑木耳产地溯源中的可行性,本研究从东北(黑龙江、吉林、辽宁)、浙江产地采集74份代表性黑木耳样品,从新疆采集11份代表性黑木耳样品作为外部验证,采用元素分析-稳定同位素比率质谱仪测定δ13C、δ15N、δ2H、δ18O值,结合化学计量学方法进行产地溯源判定。结果表明,东北黑木耳δ13C、δ15N、δ2H、δ18O值分别为-24.5‰~-22.7‰、-0.9‰~3.1‰、-62.2‰~-34.6‰、15.9‰~19.4‰;浙江黑木耳δ13C、δ15N、δ2H、δ18O值分别为-26.2‰~-24.5‰、-0.9‰~1.2‰、-24.9‰~-9.0‰、19.9‰~22.2‰,两产地黑木耳δ15N值差异不显著(P>0.05),δ13C、δ2H和... 相似文献
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为探究茶叶与茶园土壤、灌溉水源等产地环境中稳定同位素和矿物元素特征及其相关性,采用元素分析同位素质谱联用仪(EA-IRMS)和电感耦合等离子体质谱仪(ICP-MS)对山东日照和崂山的茶叶、栽培土壤及灌溉水源中4种稳定同位素比率(δ13C、δ15N、δD和δ18O)和23种矿物元素含量(Na、Mg、Al、K、Ca和Sr等)进行测定。结果显示,两地区中稳定同位素和矿物元素具有区域性特征,通过对茶叶中4种稳定同位素与栽培土壤(δ13C和δ15N)、灌溉水源(δD和δ18O)分别进行线性相关分析,结果表明,茶叶与栽培土壤中的δ15N相关性最大,R2为0.450 7,其次分别为栽培土壤中的δ13C(R2=0.289 5)、灌溉水源中的δ18O(R2=0.156 2)和δD(R2=0.021 4);同时,利用热图技术... 相似文献
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为阐明毒氟磷在动物体内的分布代谢特征,并深入认识毒氟磷的安全性和膳食风险,本研究选择白羽产蛋鸡为试验对象,[噻唑基-2-14C]-毒氟磷为同位素示踪剂,研究了毒氟磷在产蛋鸡体内的排泄分布特征。结果表明,毒氟磷在产蛋鸡体内排泄水平高,首次给药24 h后即排泄出当日给药量的82.04%,连续给药7 d后的累计排泄率为82.24%。毒氟磷在组织中的总残留仅占引入量的3.81%,其中胃中残留量占比相对最高,占引入量的2.14%,而肺、肾、脂肪、胰腺中的放射性残留量均不超过引入量的0.01%,膳食评估结果表明在上述内脏组织中的毒氟磷残留无膳食风险。蛋、肌肉、心、脑、脾、卵巢等组织中未检测到放射性残留。本研究为科学评价毒氟磷在家禽中的安全性提供了试验依据。 相似文献
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丝绸具有重要的经济与文化价值。为探究桑蚕品种对丝绸产地溯源模型准确率的影响,本研究通过桑蚕饲养试验,采用单因素方差分析(one-way ANOVA)和椭圆联合置信区间(EJCR)测试探讨桑蚕从幼虫至吐丝结茧的不同发育阶段蚕体、蚕沙样本中4种稳定同位素比值(δ13C、δ15N、δ2H、δ18O)的变化趋势,并比较不同品种对稳定同位素比值的影响。结果表明,不同龄期蚕体的δ13C、δ15N、δ2H和δ18O值变化趋势不同,且不同龄期蚕沙的稳定同位素比值变化趋势与蚕体相似。单因素方差分析结果表明,在相同饲喂条件下,除少数龄期外,不同品种之间蚕体和蚕沙样本稳定同位素组成总体不存在显著差异,且蚕体和蚕沙样本的δ13C、δ15N、δ2H相关性较强。桑蚕品种可能导致蚕茧中单个稳定同位素出现较大变化,对δ13C、δ18O影... 相似文献
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Zimmerman LR Schneider RJ Thurman EM 《Journal of agricultural and food chemistry》2002,50(5):1045-1052
Dimethenamid [2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide] and flufenacet [N-(4-fluorophenyl)-N-(1-methylethyl)-2-(5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)oxy] were isolated by C-18 solid-phase extraction and separated from their ethanesulfonic acid (ESA) and oxanilic acid (OXA) degradates during their elution using ethyl acetate for the parent compound, followed by methanol for the polar degradates. The parent compounds were detected using gas chromatography-mass spectrometry in selected-ion mode. The ESA and OXA degradates were detected using high-performance liquid chromatography--electrospray mass spectrometry (HPLC-ESPMS) in negative-ion mode. The method detection limits for a 123-mL sample ranged from 0.01 to 0.07 microg/L. These methods are compatible with existing methods and thus allow for analysis of 17 commonly used herbicides and 18 of their degradation compounds with one extraction. In a study of herbicide transport near the mouth of the Mississippi River during 1999 and 2000, dimethenamid and its ESA and OXA degradates were detected in surface water samples during the annual spring flushes. For flufenacet, the only detections at the study site were for the ESA degradates in samples collected at the peak of the herbicide spring flush in 2000. The low frequency of detections in surface water likely is due to dimethenamid and flufenacet being relatively new herbicides. In addition, detectable amounts of the stable degradates have not been detected in ground water. 相似文献
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The influence of four methods of land preparation on weed regeneration and the efficacy of imazaquin (2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1 H-imidasol-2yl]-3-quinolinecarboxylic acid) applied singly at 0.18 kg a.i. ha−1, and in tank mixture with either 2.0 kg a.i. ha−1 of metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamine) or 0.64 kg a.i. ha−1 of diuron (N′-(3,4-dichlorophenyl)-N, N-dimethylurea) in cowpea (Vigna unguiculata L. Walp.) was studied in the late season of 1989 at the University of Benin and in the early season of 1990 at the Nigerian Institute for Oil Palm Research (NIFOR), Benin City, Nigeria. The methods of land preparation were: no-tillage (NT-B with all the stubble mulch packed and burnt in situ); no-tillage (NT-Pa, the existing vegetation was killed with paraquat and the sod left in situ); ploughing (P); ploughing and harrowing (P+H). The number of regenerating weeds was significantly greater were the land was prepared by no-till and the stubble mulch left in situ compared with all other methods of land preparation. There were no significant differences in number of regenerating weeds and the weed biomass between NT-B, P and P+H. Herbicide treatments significantly reduced both the number of regenerating weeds and weed biomass irrespective of the method of land preparation. Herbicides generally performed better in NT-B, P, P+H than in NT-Pa plots. Cowpea pod or grain yield was not significantly influenced by the method of land preparation. However, it was significantly depressed where the plots were left unweeded for all methods of land preparation, especially so in the NT-Pa treatment. These observations suggest that where a good degree of burn or stubble mulch removal is achieved, further soil tillage may not necessarily enhance the efficacy of imazaquin and its tank-mixtures with diuron or metolachlor. 相似文献
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LC/MS analysis of cyclohexanedione oxime herbicides in water 总被引:1,自引:0,他引:1
A multiresidue method for the determination of alloxydim (methyl 2, 2-dimethyl-4, 6-dioxo-5-[1-[2-propenyloxy)amino]butylidene]cyclohexanec arb oxylate), clethodim (E, E)-(+/-)-2-[1-[[3-chloro-2-propenyl)oxy]imino]propyl]-5-[2-(ethylthio )propyl]-3-hydroxy-2-cyclohexen-1-one), sethoxydim ((+/-)-2-[1-(ethoxyimino)butyl]-5-[2-ethylthio)propyl]-3-hydroxy-2 -cy clohexen-1-one), and two metabolites, clethodim sulfoxide ((E, E)-(+/-)-2-[1-[[3-chloro-2-propenyl)oxy]imino]propyl]-5-[2-(ethylsulf inyl)propyl]-3-hydroxy-2-cyclohexen-1-one) and sethoxydim sulfoxide ((+/-)-2-[1-(ethoxyimino)butyl]-5-[2-ethylsulfinyl)propyl]-3 -hydroxy- 2-cyclohexen-1-one), in water by high-performance liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) is reported. River water and distilled water were spiked at 0.08 and 0.8 microgram L(-1) with all three herbicides, which were then extracted from the water by C(18)-SPE (SPE = solid-phase extraction). The herbicides and metabolites were quantified and confirmed using selected ion monitoring. The percent recoveries of the herbicides from water spiked at 0.8 microgram L(-1) were as follows: alloxydim, 117 +/- 11%; clethodim, 96 +/- 14%; sethoxydim, 89 +/- 13%. There was no evidence of oxidation of clethodim and sethoxydim during the extraction to their respective sulfoxides. The limit of quantitation was <0.1 microgram L(-1). We have shown that we can analyze and confirm three cyclohexanedione oxime herbicides and two metabolites in water by LC/ES/MS. This multiresidue method should also be appropriate for other cyclohexanedione oximes. 相似文献
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Samples of fresh Sphagnum peat from a raised bog were amended with 14 C-labelled glycine. The distribution of 14 C between particle size fractions obtained by wet sieving (sieve sizes 1, 0.5, 0.25, 0.15 and 0.05mm) was determined immediately on control (unincubated) samples and after 1, 6 and 12 months incubation at 10°C. The recovery of glycine in solution was almost 100%. During the incubation with 14 C-glycine, 14 CO2 was released within the first 20 weeks, equivalent to 51.5% of the added 14 C, but thereafter very little 14 CO2 was evolved. After 26 weeks a substantial amount of 14 C was distributed amongst all the fractions, but the greatest incorporation (4.47%) occurred in the finest fraction (0.005–0.05 mm). Labelling of the other particle size fractions was <2.3% of added 14 C. Carbohydrate accounted for 23% of 14 C in the finest fraction and the sugars, rhamnose, arabinose, xylose, mannose, galactose and glucose all became labelled. Rhamnose showed the greatest, and arabinose, galactose and xylose the least, increase in specific activity; glucose and mannose had intermediate values. It was concluded that the finest fraction in peat contains a significant proportion of the microbially-synthesized material. 相似文献
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A variety of [14C]labeled organic compounds and microbial products were incubated in soil alone or intimately associated with humic acid-type polymers achieved by freeze-drying mixed solutions of the polymers and [14C]labeled compounds at pH 6. The association of Chlorella protein with the polymers reduced mineralization over 12 weeks by 41%. Similarly decomposition of cysteine and Anabaena flos-aqua cytoplasm was reduced by 26% and glycine 16%. Tyrosine, lysine, aspartic acid, serine, cytosine, glucose, ferulic acid. also polysaccharides of Leuconostoc dextranicus, Azotobacter indicus, Hansenula holstii and Anabaena flos-aqua, as well as cells and cell walls of A. flos-aqua decomposed just or almost as readily when intimately associated with humic polymers as when added alone to the soils. The association with humic polymers did not influence the distribution of residual activity in humic acid, fulvic acid and extracted soil following incubation. 相似文献
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Short pulse-chase labeling experiments indicated that there was a considerable difference between soybean and rice in the distribution pattern of 14 C to major metabolites during a 300 s chase period. The distribution of 14 C to starch at the end of the chase period was largest in soybean but very small in rice. In rice, the distribution of 14 C to sucrose was the largest. Starch formation during the initial stages of photosynthesis implied the existence of a different mechanism of starch synthesis and utilization between soybean and rice. The relative intensity of the flow into starch increased by treatment with 2% O2 , suggesting that photorespiratory pathway may involve in the regulation of higher starch accumulation in soybean. 相似文献