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Jos I Prez‐Martínez Juan M Gins Esmeralda Morillo María L Gonzlez‐Rodríguez Jos R Moyano Mndez 《Pest management science》2000,56(5):425-430
Inclusion complex formation of 2,4‐dichlorophenoxyacetic acid (2,4‐D) with hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) has been proposed as a way of modifying the behaviour of the pesticide in the soil environment. The present study assesses the effect of complex formation on 2,4‐D physicochemical properties (aqueous solubility, crystallinity and dissolution rate) and its behaviour on soils. The solid complexes were prepared using different methods (spray drying, kneading and heating in a sealed container). To confirm the complex formation in the solid state differential scanning calorimetry, hot stage microscopy and x‐ray diffraction techniques were employed. Complex formation in solution was studied by phase solubility. The presence of HP‐β‐CD increased the 2,4‐D solubility nine times approximately. The apparent stability constant was determined as 98.6 M −1. The dissolution rates of the 2,4‐D/HP‐β‐CD complexes were examined and compared with that of the pure pesticide. The results indicated that the complex may have great utility as a rapid way of dissolving the pesticide. Batch experiments were performed to study the adsorption–desorption of 2,4‐D on soils and the influence of the HP‐β‐CD over these processes. The results showed that HP‐β‐CD could increase the desorption of 2,4‐D previously adsorbed on soils. © 2000 Society of Chemical Industry 相似文献
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A three-year field study was conducted using twelve 7.4×3.7 m plots and simulated rainfall to investigate pesticide run-off following application to a golf course fairway. The plots were sprigged with ‘Tifway 419’ bermudagrass (Cynodon dactylon×C transvaalensis). The dimethylamine salt of 2,4-D [(2,4-dichlorophenoxy)acetic acid] was applied as foliar sprays at a rate of 2.24 kg AI ha−1. Simulated rainfall was applied at an intensity of 29 mm h−1 one day before and 1, 2, 4, and 8 days after the pesticide applications for 0.92, 1.75. 1.75, 0.92, and 0.92 h, respectively. Water run-off was measured using a tipping-bucket apparatus and sub-samples were analyzed for pesticide residues. Data collected from the study were also compared with the GLEAMS and PRZM-2 model simulations for surface water and 2,4-D run-off. Mass and concentration of 2,4-D in run-off decreased rapidly, with 74.5% of the total run-off of 2,4-D occurring in the first run-off event after treatment. When calibrated to the site-specific characteristics, the GLEAMS and the PRZM-2 models adequately simulated the average of surface water run-off over all plots, with normalized root mean square error (NRMSE) and coefficient of determination for linear regression (R2) being 22.8% and 0.917 for GLEAMS, and 23.7% and 0.879 for PRZM-2, respectively. However, both GLEAMS (NRMSE=82.1%, R2=0.776) and PRZM-2 (NRMSE=125.8%, R2=0.513) less accurately simulated 2,4-D concentrations in run-off. © 1999 Society of Chemical Industry 相似文献
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BACKGROUND: Variations in soil properties with depth influence retention and degradation of pesticides. Understanding how soil properties within a profile affect pesticide retention and degradation will result in more accurate prediction by simulation models of pesticide fate and potential groundwater contamination. Metolachlor is more persistent than other acetanilide herbicides in the soil environment and has the potential to leach into groundwater. Reasonably, information is needed about the dissipation and eventual fate of metolachlor in subsoils. The objectives were to evaluate the adsorption and desorption characteristics and to determine the dissipation rates of metolachlor in both surface and subsurface soil samples. RESULTS: Adsorption of metolachlor was greater in the high‐organic‐matter surface soil than in subsoils. Lower adsorption distribution coefficient (Kads) values with increasing depth indicated less adsorption at lower depths and greater leaching potential of metolachlor after passage through the surface horizon. Desorption of metolachlor showed hysteresis, indicated by the higher adsorption slope (1/nads) compared with the desorption slope (1/ndes). Soils that adsorbed more metolachlor also desorbed less metolachlor. Metolachlor dissipation rates generally decreased with increasing soil depth. The first‐order dissipation rate was highest at the 0–50 cm depth (0.140 week?1) and lowest at the 350–425 cm depth (0.005 week?1). Degradation of the herbicide was significantly correlated with microbial activity in soils. CONCLUSION: Metolachlor that has escaped degradation or binding to organic matter at the soil surface might leach into the subsurface soil where it will dissipate slowly and be subject to transport to groundwater. Copyright © 2009 Society of Chemical Industry 相似文献
5.
Adsorption and desorption of pyrazone by some organic and mineral colloids The adsorption and desorption of pyrazone on organic and mineral colloids and on ion-exchanging resins saturated with H+, Na+, K+, Ca++ and Mg++ ions was studied. The following order of adsorption was found for H-adsorbants: H-Amberlite> Dowex-H > H-humus > Al,H-montmorillonite> Al,H-illite> Al,H-kaolinite. This adsorption, which seems to be due to physical links and not to protonation mechanisms, is greater than that found with the -K, -Na, -Ca, and -Mg systems. With Ca- systems the same order of adsorption was obtained: Dowex-Ca>Ca-montmorillonile>Ca-illite> Ca-kaolinite. In contrast to what we found with Dowex resin, with montmorillonlte and illite the saturating cation seemed to affect adsorption of pyrazone; indeed we obtained the following order: Ca++> Mg++> K+> Na+. For all the systems we examined desorption of the adsorbed pyrazone was complete. 相似文献
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Working with Malaysian agricultural soils, high Freundlich adsorption distribution coefficients (Kads(f)) were observed for paraquat (28·7 and 1419) and glyphosate (83·8 and 417) and lower values for 2,4-D (0·57 and 5·26) and lindane (2·65 and 14·1) in a sandy loam and a muck soil, respectively. Desorption of 2,4-D and lindane from the muck soil occurred. The adsorption of the pesticides was not affected by temperature (20°C/30°C), pH or addition of the pesticides as a mixture. Leaching of 2,4-D and lindane was evident under a high water influx (200 mm). Comparable results in the leaching of 2,4-D were observed between laboratory studies and a VARLEACH model prediction. © 1997 SCI. 相似文献
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The photocatalytic transformation of 2,4-D in aqueous solution containing a suspension of titanium dioxide or zinc oxide leads to the formation of intermediates which are totally mineralised to carbon dioxide and hydrogen chloride (2,4-dichlorophenol and chlorohydroquinone are the major intermediates). The products at the initial stage of the reaction were 2,4-dichlorophenol (2,4-DCP), chlorohydroquinone, 4-chloropyrocatechol, 2,4-dichloropyrocatechol and 1,4-chlorobenzoquinone. The initial rate of photodegradation was studied as a function of the initial concentration of reactants by the linearised form of the Langmuir–Hinshelwood equation, by which rate constants k and equilibrium adsorption constants K were evaluated. These constants were calculated at different temperatures between 25 and 60°C. The photodegradation rate increased with increase of pH. The photocatalytic transformation of 2,4-D over titanium dioxide or zinc oxide in solution containing hydrogen peroxide was studied. The latter accelerated the reaction rate of 2,4-D significantly. It was found that chloride or bicarbonate ions slowed down the photodegradation rate of 2,4-D by scavenging hydroxyl radicals. Partial inhibition by ethanol is attributed to scavenging of the OH radicals involved in the first step of the reaction. © 1998 Society of Chemical Industry 相似文献
8.
E Gonzlez‐Pradas M Villafranca‐Snchez F Del Rey‐Bueno M
D Urea‐Amate M Fernndez‐Prez 《Pest management science》2000,56(6):565-570
The adsorption of paraquat (1,1′‐dimethyl‐4,4′‐bipyridilium dichloride) and atrazine (6‐chloro‐N 2‐ethyl‐N 4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) from aqueous solution onto two montmorillonite‐(Ce or Zr) phosphate cross‐linked compounds at different temperatures (288 K and 308 K) has been studied using batch experiments. The adsorption isotherms obtained for paraquat on both adsorbents may be classified as H‐type of the Giles classification, which suggests that paraquat molecules are strongly adsorbed on the samples. For the adsorption of atrazine, L‐type isotherms were obtained for both montmorillonite‐(Ce or Zr) phosphate compounds, which suggests that these compounds have a medium affinity for this herbicide. The increase in temperature from 288 K to 308 K did not have any clear effect on the adsorption process of paraquat on either adsorbent whereas atrazine adsorption decreased slightly as temperature increased, possibly due to a mainly physical process. Fourier transform infrared (FTIR) spectroscopic studies revealed that at the pH generated by the adsorbents, the cationic herbicide interacted to a greater extent with the negatively charged surface of the adsorbents than did atrazine. For both herbicides, the Ce‐montmorillonite adsorbent showed a higher adsorption capacity than the Zr‐montmorillonite adsorbent. © 2000 Society of Chemical Industry 相似文献
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Studies of the absorption and translocation of 14C-2,4-D in Chenopodium album L., Galinsoga parviflora Cav., Datura stramonium L. and Galium aparine L. in relation to their susceptibility gave the following results: In G aparine (resistant) there was little transport of 2,4-D applied to the leaves, and a probable relationship between resistance and the immediate binding of the 2,4-D in the treated leaf. D. stramonium (relatively resistant) transported 2,4-D in considerable amounts alter uptake through the leaf, while C. album (very susceptible) and G. parviflora (susceptible) were intermediate in respect of 2,4-D translocation. No relationship between susceptibility of these four species and 2,4-D uptake and translocation from the leaves could be established. After application to the root systems of the four species, 2,4-D was taken up and translocated in the shoot to varying extents. In G. aparine much 2,4-D was taken up and translocated. In contrast to leaf application, the herbicide was not immediately converted into a strongly-held immobile form. In C. album, G. parviflora and D. stramonium, however, no 2,4-D was translocated in the shoot. There was thus no correlation between susceptibility and shoot transport of 2,4-D in the four species studied. Distribution du 2,4-D marqué au 14C dans des espèces de mauvaises herbes présentant des sensibilités diverses 相似文献
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Cells were isolated from the developing leaves of Ipomoea aquatica and Digitaria sanguinalis. The effects of phenoxy alkanoic acid herbicides on light-dependent 14CO2 fixation and oxygen evolution in these leaf cells were studied. (2,4-Dichlorophenoxy)acetic acid and (2,4,5-trichlorophenoxy) acetic acid (2,4,5-T and 2,4-D) caused a 20% stimulation of 14CO2 fixation at 0.8 × 10−5M and an inhibition at 1 × 10−4M in I. aquatica leaf cells. Temperature seemed to have a marked influence on such action. No effect or very little effect was observed in the leaf cells of D. sanguinalis. The nonactive (2,4,6-Trichlorophenoxy)acetic acid (2,4,6-T) caused a similar stimulation of CO2 fixation as 2,4-D and 2,4,5-T at low concentrations in I. aquatica leaf cells, but no inhibition was observed at high concentration. Increase of hight intensity increased the rate of CO2 fixation in both control and 2,4,6-T-treated cells; however, the percentage of stimulation remained the same. At stimulatory concentration, all three compounds did not cause any stimulation in either photosystem I and II or photosystem II-mediated oxygen evolution. At higher concentrations, the differential effects of 2,4-D and 2,4,5-T on the light-induced CO2 fixation and photosystem II-mediated oxygen evolution in the I. aquatica leaf cells and D. sanguinalis mesophyll (ms) cells may be attributed in part to their selective action against dicotyledonous plants. 相似文献
11.
Non-enzymic and peroxidase-catalysed oxidative decarboxylations of tryptophan (TPP) were studied. The in-vitro rate of enzymic reaction was affected by various herbicides at low concentrations (10?5?10?4M): dinoseb, 2,4-D, dichlobenil and benazolin acted as inhibitors; on the other hand, chlorpropham, bromacil, diphenamid and 4-ethylamino-6-isopropylamino-1,3,5-triazin-2-ol (hydroxyatrazine) were stimulatory. The results of in-vivo experiments showed that chlorpropham and 2,4-D changed the activity of peroxidase from Brassica germinated seeds in vivo, as they do in vttro. Determinations of consumed TPP were carried out either by spectro-photometry or by chromatography. 相似文献
12.
ALLAN E. SMITH 《Weed Research》1984,24(4):291-295
The persistence of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), [14C]dicamba (3,6-dichloro-2-methoxybenzoic-7-14C acid) and propanil [N-(3,4-dichlorophenyl)propionamide] at rates equivalent to 1 kg ha?1, were studied under laboratory conditions in a clay loam, a heavy clay and a sandy loam at 85% of field capacity and at 20±1°C, both singly and in the presence of herbicides normally applied with these chemicals as tank-mix or split-mix components. The degradation of bromoxynil was rapid with over 90% breakdown occurring within a week in the heavy clay and sandy-loam soils, while in the clay-loam approximately 80% of the bromoxynil had broken down after 7 days. In all three soils degradation was unaffected by the presence of asulam, diclofop-methyl, flamprop-methyl, MCPA, metribuzin or propanil. Propanil underwent rapid degradation in all soil treatments, with over 95% of the applied propanil being dissipated within 7 days. There were no noticeable effects on propanil degradation resulting from applications of asulam, barban, bromoxynil, dicamba, MCPA, MCPB, metribuzin or 2,4-D. The breakdown of [14C]dicamba in a particular soil was unaffected by being applied alone or in the presence of diclofop-methyl, flampropmethyl, MCPA, metribuzin, propanil or 2,4-D. The times for 50% of the applied dicamba to be degraded were approximately 16 days in both the clay loam and sandy loam, and about 50 days in the heavy clay. 相似文献
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Ring- and carboxyl-labelled [14C]2,4-D were incubated under laboratory conditions, at the 2 g/g level, in a heavy clay, sandy loam, and clay loam at 85% of field capacity and 20 1C. The soils were extracted at regular intervals for 35 days with aqaeous acidic acetonitrile, and analysed for [14C]2,4-D and possible radioactive degradation products. Following solvent extraction, a portion of the soil residues were combusted in oxygen to determine unextracted radioactivity as [14C]carbon dioxide. The remaining soil residues were then treated with aqueous sodium hydroxide, and the radioactivity associated with the fulvic and humic soil components determined. In all soils there was a rapid decrease in the amounts of extractable radioacitivity, with only 5% of that applied being recoverable after 35 days. All recoverable radioactivity was attributable to [14C]2,4-D, and no [14C]-containing degradation products were observed. This loss of extractable radioactivity was accompanied by an increase in non-extractable radioactivity. Approximately 15% of the applied radioactivity, derived from carboxyl-labelled [14C]2,4-D, and 30% from the ring-labelled [14C]2,4-D was associated with the soil in a non-extractable form, after 35 days of incubation. After 35 days, less than 5% of the radioactivity from the carboxyl-labelled herbicide, and less than 10% of the ringlabelled material, was associated with the fulvic components derived from the three soils. Less than 5% of the applied radioactivities were identifiable with any of the humic acid components. It was considered that during the incubation [14C]2,4-D did not become bound or conjugated to soil components, and that non-extractable radioactivity associated with the three soil types resulted from incorporation of radioactive degradation products, such as [14C]carbon dioxide, into soil organic matter. 相似文献
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A. J. SANAD 《Weed Research》1971,11(4):215-223
Studies of the uptake and translocation of 14C-labelled 2, 4-D, MCPA and aminotriazole in Agrostemma githago L. and Tussilago farfara L. clarified the behaviour of the herbicides in both species. In A. githago, MCPA was more freely mobile than 2,4-D after application to the leaf; it was distributed in the plant more rapidly and in greater quantity. Similarly, following root uptake MCPA was transported in the shoot in greater amounts than was 2,4-D. There is a clear relationship between the susceptibility of A. githago to MCPA and the mobility of the herbicide in the plant. In T. farfara, 2,4-D and aminotriazole applied to the leaves were equally well absorbed and relatively rapidly translocated. During the period up to 72 h the amounts of herbicide in the plant increased to similar levels; after that, 14C activity in plants treated with 2,4-D fell slightly whereas there was further accumulation of aminotriazole. Following uptake through the roots, translocation and accumulation in the leaves were considerably greater with aminotriazole than with 2,4-D. The lack of accumulation of 2,4-D could be a factor in the resistance of T. farfara to this herbicidie. Recherches sur l'absorption et la migration d'herbicides marqués au 14 C dans Agrostemma githago L. et Tussilago farfara L. 相似文献
15.
Influence of organic material and soil moisture content on the adsorption of aniline Adsorption of aniline is directly related to the organic content of the soil and appears to depend mainly on the humic acid content. The competitive effect of soil water in the adsorption of aniline was examined. The influence of colloidal suspensions on adsorption was such that in natural surroundings only trace quantities of aniline were found in soil liquid. In every case, desorption was accompanied by a pronounced hysteresis effect, but salt solutions (CaCl2) had the greatest ability to displace adsorbed aniline. 相似文献
16.
Experiments were conducted to examine the up take, translocation and metabolism by S. vulgaris of two distinctly different herbicides: 2,4-D, a phenoxyalkanoic acid with growth regulator activity to which this species exhibits complete tolerance, and chlorsulfuron, a sul-fonylurea to which S. vulgaris is highly sensitive. Despite their structural dissimilarities 2,4-D and chlorsulfuron was readily absorbed by S. vulgaris with 65 and 69%, respectively, of the applied dosage being absorbed within 72 hours after treatment. Approximately 35% of the 2,4-D and 10% of the chlorsulfuron label was translocated out of the treated leaf after 72 hours. Neither herbicide accumulated in the terminal bud. Seventy-two hours after treatment 63% of the recovered 14C remained as unaltered 2,4-D in S. vulgaris, while in tomato, a 2,4-D sensitive species, 65% of the recovered 14C remained as intact herbicide. In S. vulgaris approximately 86% of the radioactivity remained as intact chlorsulfuron 72 hours after treatment compared to 12% in the tolerant wheat. The tolerance of S. vulgaris to 2,4-D could not be accounted for by limited absorption, translocation nor metabolic degradation of the herbicide. The sensitivity of S. vulgaris to chlorsulfuron would appear to be related to the inability of this species to metabolize the herbicide molecule. 相似文献
17.
After feeding 2,4-D or atrazine in a diet to southern armyworm (Spodoptera eridania Cram.) larvae for three days, the effect on total content and activities of cytochrome P450 and on insecticide toxicity were determined. Both 2,4-D and atrazine induced cytochrome P450-catalyzed aldrin epoxidation (AE) and methoxyresorufin O-demethylatin (MROD). The 2,4-D was a more potent inducer for total cytochrome P450 content, whereas atrazine disproportionately increased AE. Both compounds increased MROD significantly. The apparent kinetic characteristics of AE indicates that 2,4-D and atrazine induced similar P450 isozymes (Km 8.78 and 7.80 μM, respectively), which may differ from the constitutive isozyme (Km 3.14 μM). The 2,4-D-induced cytochrome P450 contributed to decreased carbaryl and permethrin toxicity, whereas the atrazine-induced cytochrome P450 caused decreased parathion and permethrin toxicity. The carbaryl toxicity correlated directly with 2,4-D-induced total P450 content and activities but not with atrazine-induced changes. The 2,4-D and atrazine also induced nonspecific esterase activity which may contribute to permethrin detoxification. 相似文献
18.
首次以氯甲基化交联聚苯乙烯树脂(CMCPS)为载体和大分子引发剂、2,4-二氯苯氧乙酸(2,4-D)为模板、丙烯酰胺(AM)为单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂、溴化铜/2,2'-联吡啶(CuBr/Bpy)为催化剂,采用表面引发原子转移自由基聚合(SI-ATRP)技术,制备了2,4-二氯苯氧乙酸分子印迹聚合物(2,4-D MIPs),并研究了模板分子与功能单体比例对该印迹聚合物吸附量的影响。通过动态、静态及竞争试验考察了该印迹聚合物对2,4-D的吸附性能。结果表明:2,4-D MIPs对模板分子2,4-D具有良好的特异性识别作用;与2,4-二氯苯酚和2,4-二氯苯甲醛相比,2,4-D MIPs对2,4-D的选择性系数分别为2.84和3.75,相对选择性系数分别为2.31和2.29。采用Scatchard模型分析,可以得到两类结合位点,计算得到最大表观吸附量(Qmax)分别为76.92和142.91 mg/g,离解常数Kd分别为632.91和2 309.47 mg/L。将2,4-D MIPs作为固相萃取剂,对豆芽样品进行添加回收试验,回收率为86%~104%,相对标准偏差(RSD)为1.9%~10%,方法的检出限为20 ng/g。该印迹聚合物可以富集分离测定2,4-D,稳定性好,并且能重复使用。 相似文献
19.
Effects of droplet size and carrier volume on foliar uptake and translocation of gibberellic acid (GA3) and 2,4-D were investigated. Simulated spray droplets were applied to primary leaves of 10-day-old Phaseolus vulgaris (cv Nerina) in droplet sizes and carrier volumes ranging from 0.5 to 10 μl and 10 to 200 μl per leaf, respectively. Doses of GA3 (2 μg per leaf) and 2,4-D (100 μg per leaf) were held constant. Total uptake of GA3 approached a penetration equilibrium within 24 h after application, but uptake of 2,4-D continued to increase. Decreasing droplet size and/or increasing carrier volume increased GA3 and 2,4-D uptake. Translocation to stem and roots was positively related to total uptake. A positive linear relationship between the logarithm of the total droplet/leaf surface interface area and 2,4-D uptake or translocation was found, but for GA3 this relationship was quadratic. Potential mechanisms of the effects of spray application factors on foliar uptake are discussed. © 1999 Society of Chemical Industry 相似文献
20.
Annie Dufaud Jean-Franois Chollet Jr
me Rudelle Lone Miginiac Jean-Louis Bonnemain 《Pest management science》1994,41(4):297-304
The synthesis of several derivatives of a pesticide and an α-amino acid are described. The process involves three steps, the last one (deprotection of the α-amino acid group) being the most critical. The resulting products preserved their α-amino acid group and were globally neutral. They were tested for their effect on the transport of a neutral amino acid, threonine, and two sugars, sucrose and glucose. Two derivatives markedly and specifically inhibited threonine uptake by leaf tissues of Vicia faba L. and phloem loading. Preliminary experiments suggested that the lysine-2,4-D derivative is a competitive inhibitor of threonine uptake. The apparent Ki (0.5 mM) was much lower than the apparent Km (3 mm) of the natural substrate. 相似文献