共查询到20条相似文献,搜索用时 15 毫秒
1.
Dailey OD 《Journal of agricultural and food chemistry》2004,52(22):6742-6746
Pesticides may be dispersed throughout the environment by several means, including groundwater contamination, surface water contamination, and volatilization with subsequent atmospheric transport and deposition. In earlier research primarily directed at reducing the potential for groundwater contamination, a number of herbicides were microencapsulated within several different polymers. These polymeric formulations were evaluated for efficacy in the greenhouse. In the studies described in this paper, three polymeric alachlor formulations that were the most effective in the greenhouse were evaluated in laboratory volatility studies using pure alachlor and a commercial formulation (Lasso 4EC) for comparison purposes. In a given experiment, technical alachlor, Lasso 4EC, and two polymeric formulations were applied to soil and evaluated in a contained system under 53% humidity with a fixed flow rate. Evolved alachlor was collected in ethylene glycol, recovered with C18 solid phase extraction cartridges, and analyzed by reverse-phase high-performance thin-layer chromatography with densitometry. Duration of the studies ranged from 32 to 39 days. In studies in which all formulations were uniformly incorporated in the soil, total alachlor volatilization from the polymeric microcapsules was consistently lower than that from the alachlor and Lasso 4EC formulations. In studies in which the polymeric formulations were sprinkled on the surface of the soil, microcapsules prepared with the polymer cellulose acetate butyrate released the smallest quantity of volatilized alachlor. 相似文献
2.
R G Nash 《Journal of the Association of Official Analytical Chemists》1990,73(3):438-442
Extraction of several nitrogen-containing pesticides from water on solid-phase C18 cartridges was rapid and accurate. One analyst can extract greater than 48 samples/day. Recovery efficiencies were 77, 95, 92, 90, and 99% with detection limits of 0.20, 0.05, 0.05, 0.20, and 0.10 micrograms/L for carbofuran, atrazine, simazine, alachlor, and, cyanazine, respectively. Extraction of the atrazine and simazine dealkylation products (deethylatrazine and deethylsimazine) was less efficient, e.g., 26 and 9%, respectively. Comparisons with 10 U.S. Geological Survey samples gave similar results. 相似文献
3.
Abstract. The influence of conventional and soil-specific management on leaching and runoff losses of soil-applied alachlor (2-chloro-2',6'-diethyl- N -(methoxymethyl) acetanilide) was studied across a soil catena (landscape) with varied slope and drainage characteristics. The catena consisted of: a well-drained Ves (fine-loamy, mixed, mesic Udic Haplustoll) soil on the backslope (1–4%), a Ves soil on the sideslope (6–12%), and a poorly drained Webster (fine-loamy, mixed, mesic Typic Haplaquoll) soil on the toeslope (0–3%). In general, the concentration of alachlor in runoff water was greater in the Ves soil than in the Webster. In 1992 alachlor concentrations in runoff (water, sediment + water) were less for soil-specific rates (2.20 or 2.80 kg/ha) than for a uniform rate (3.36 kg/ha) in both Ves soils. There was no significant difference in alachlor concentration related to application rates (soil-specific rate 3.66 kg/ha) in the runoff from the Webster soil. Averaged across soils and events, the concentrations of alachlor in runoff (water, sediments + water) were less for soil-specific rates than for the uniform rate. Alachlor was not detected in soil samples obtained from depths greater than 15 cm in any soil or treatment after the first sampling. At the first sampling in 1992 (7 days after application) alachlor was detected down to 45 and 90 cm in the Ves and Webster soils, respectively. Detectable amounts (≥0.1 μg/1) of alachlor were observed in soil water samples extracted from all three soils during some sampling dates. No particular trends were observed with soils or application rates. 相似文献
4.
Anastasia E.M. Chirnside William F. Ritter Mark Radosevich 《Soil biology & biochemistry》2009,41(12):2484-2492
A selected microbial consortium (SMC) capable of degrading two specific herbicides, alachlor (2-chloro-2′,6′-diethyl-N-[methoxymethyl]-acetanilide; AL) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-S-triazine; AT) was isolated from a pesticide-contaminated mix-load site soil. Evaluation of bioaugmentation as a feasible bioremediation strategy for this mix-load site soil (Site 5A) was initiated in standard laboratory biometer flasks utilizing the isolated SMC. The biometer flasks were monitored for CO2 evolution and pesticide degradation. The total amount of CO2 evolved from the treated biometer flasks was significantly different from the control flasks. The rate of CO2 evolution was 2.6 times faster in the treated soil (0.0123 mM CO2 d−1 vs. 0.0048 mM CO2 d−1). The total net CO2 produced in the treated biometer flasks was 0.9481 mM, representing mineralization of approximately 10% of the AT and AL initially present. Forty-eight percent of AT and 70% of AL was degraded in the inoculated biometer flasks. The first-order rate constants were 0.0064 d−1 and 0.1331 d−1 for AT and AL, respectively. The calculated half-life of AT was 108 d while a 50% decrease in AL occurred by Day 5. In just 2 d, 20% of the AT was degraded while only 10% of the AL disappeared. The initial fast degradation rate of AT was followed by a much slower, more gradual degradation rate period that lasted about 35 d. Alternatively, the rate of AL degradation increased after the second day resulting in 60% of the AL being transformed by the end of the first week. Alachlor degradation appeared to be dependent upon AT degradation especially during the first several days of the incubation period. Complete disappearance of the herbicides over the study time was not achieved. 相似文献
5.
Fernández-Pérez M Flores-Céspedes F González-Pradas E Villafranca-Sánchez M Pérez-García S Garrido-Herrera FJ 《Journal of agricultural and food chemistry》2004,52(12):3888-3893
The herbicide atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) was incorporated in alginate-based granules to obtain controlled-release (CR) properties. The basic formulation [sodium alginate (1.40%)-atrazine (0.60%)-water] was modified by the addition of sorbents. The effect on atrazine release rate caused by the incorporation of acid-treated bentonite (0.5 and 2.5 M H2SO4) in alginate formulation was studied by immersion of the granules in water under static conditions. The water uptake, sorption capacity of the sorbent, permeability, and time taken for 50% of the active ingredient to be released into water, t50, were calculated for the comparison of the preparations. t50 values were longer for those formulations containing acid-treated bentonite (36.78 and 29.01 days for 0.5 and 2.5 M H2SO4 treatments, respectively) than for the preparation without bentonite (9.69 days). On the basis of a parameter of an empirical equation used to fit the herbicide release data, it appears that the release of atrazine from the various formulations into water is controlled by diffusion mechanism. The sorption capacity of the sorbents and the permeability of the formulations (ranging from 4.99 to 20.83 mg day(-1) mm(-1)) were the most important factors affecting herbicide release. 相似文献
6.
L Q Huang 《Journal of the Association of Official Analytical Chemists》1989,72(2):349-354
A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of 15N,13C-alachlor and 2H5-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples. 相似文献
7.
The release of alachlor from controlled-release formulations (CRFs) based on alginate-montmorillonite matrices into aqueous polyethylene glycol (PEG) solutions of different concentrations and into a soil at different moisture contents was studied. In distilled water and in PEG-containing solutions displaying -0.1 MPa potential and up, the beads imbibe water and swell. The ensuing increase in weight is about 5%, and the increase in the bead's diameter is about 10%. At water potentials of -0.5 MPa and lower, loss of weight and shrinkage of the beads were observed. The changes in weight and diameter of the alginate-clay beads incubated in a Hamra loamy sand soil at 26.5% moisture content (w/w; -0.18 MPa) were similar to those observed in PEG solutions of >-0.5 MPa moisture potential. The weight and diameter losses observed in the drier soils (12.0 and 7.1% water content; -0.49 and -1.11 MPa) were similar to those in the more concentrated PEG solutions. A decrease in the rate of release of the active ingredient from the beads into soil was observed as the water potential decreased (drier soils). The release of the active ingredient from the investigated CRFs displayed a linear relationship to the square root of time, suggesting a diffusion-controlled-release rate. Data extracted from this relationship enabled the formulation of a mathematical model that correlates rate of release to water content. 相似文献
8.
Ethylcellulose formulations for controlled release of the herbicide alachlor in a sandy soil 总被引:1,自引:0,他引:1
Sopeña F Cabrera A Maqueda C Morillo E 《Journal of agricultural and food chemistry》2007,55(20):8200-8205
The development of controlled-release formulations of alachlor to diminish its leaching in sandy soils, avoiding groundwater contamination and maintaining its efficacy, was studied. For this purpose, ethylcellulose (EC) microencapsulated formulations (MEFs) of alachlor were prepared under different conditions and applied to soil columns to study their mobility. The results show that in all cases the release into water of alachlor from MEFs was retarded when compared with commercial formulation. Total leaching losses in soil columns were reduced to 59% from 98%. The mobility of alachlor from EC microspheres into soil columns has been greatly diminished in comparison with its current commercial formulation (CF), above all with increasing EC/herbicide ratios. Distribution of alachlor applied as MEFs at different depths in the soil was higher in the soil surface (66.3-81.3% of herbicide applied at the first 12 cm). In contrast, the residues from CF along the complete soil column were only 20.4%. From the results of bioassays, MEFs showed a higher efficacy than CF at 30 days after the treatment. The use of ME formulations could provide an advantage in minimizing the risk of groundwater contamination by alachlor and reducing the application rates, as a result of maintaining the desired concentration of the herbicide in the top soil layer, obtaining longer periods of weed control. 相似文献
9.
Bhawana Basniwal RK Buttar HS Jain VK Jain N 《Journal of agricultural and food chemistry》2011,59(5):2056-2061
Curcumin is a highly potent, nontoxic, bioactive agent found in turmeric and has been known for centuries as a household remedy to many ailments. The only disadvantage that it suffers is of low aqueous solubility and poor bioavailability. The aim of the present study was to develop a method for the preparation of nanoparticles of curcumin with a view to improve its aqueous-phase solubility and examine the effect on its antimicrobial properties. Nanoparticles of curcumin (nanocurcumin) were prepared by a process based on a wet-milling technique and were found to have a narrow particle size distribution in the range of 2-40 nm. Unlike curcumin, nanocurcumin was found to be freely dispersible in water in the absence of any surfactants. The chemical structure of nanocurcumin was the same as that of curcumin, and there was no modification during nanoparticle preparation. A minimum inhibitory concentration of nanocurcumin was determined for a variety of bacterial and fungal strains and was compared to that of curcumin. It was found that the aqueous dispersion of nanocurcumin was much more effective than curcumin against Staphylococcus aureus , Bacillus subtilis , Escherichia coli , Pseudomonas aeruginosa , Penicillium notatum , and Aspergillus niger . The results demonstrated that the water solubility and antimicrobial activity of curcumin markedly improved by particle size reduction up to the nano range. For the selected microorganisms, the activity of nanocurcumin was more pronounced against Gram-positive bacteria than Gram-negative bacteria. Furthermore, its antibacterial activity was much better than antifungal activity. The mechanism of antibacterial action of curcumin nanoparticles was investigated by transmission electron micrograph (TEM) analysis, which revealed that these particles entered inside the bacterial cell by completely breaking the cell wall, leading to cell death. 相似文献
10.
Background, aim, and scope
Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) is one of the most widely used herbicides for broadleaf weed and certain annual grass controls and is popular because of its effectiveness and low cost. Losses of atrazine from agricultural lands into adjacent surface water and underlying groundwater have raised public concerns. Several computer models have been developed for atrazine runoff in watersheds. One limitation for most of these models, however, is that vast amounts of input parameters are required for simulations. These input parameters are sometimes difficult to obtain through the experimental measurements for model calibrations, validations, and applications. Therefore, a need exists to develop a simple and yet a realistic modeling tool that can be used for effectively investigating atrazine dynamics in agricultural soils. This study was designed to meet this need. 相似文献11.
Herbicide sorption, degradation, and leaching in three Swedish soils under long-term conventional and reduced tillage 总被引:2,自引:0,他引:2
Mats Larsbo John Stenstrm Ararso Etana Elisabet Brjesson Nicholas J. Jarvis 《Soil & Tillage Research》2009,105(2):200-208
Soil tillage has the potential to influence water flow and solute transport through the soil by cutting continuous macropores which connect the soil surface to the subsoil. Tillage also affects soil organic carbon sequestration which may lead to different sorption and degradation properties depending on the long-term tillage practices. The objective of this study was to quantify the differences in sorption, degradation and leaching of the herbicides bentazone and isoproturon between conventional tillage (CT) and reduced tillage (RT) under Swedish conditions. Three sites, Ultuna (silty clay), Säby (loam), and Lönnstorp (sandy loam moraine till), where replicate plots had been under either CT or RT for at least 9 years, were included in the study. A higher organic carbon content had developed in the top 5 cm of RT plots compared to the 10–20 cm depth and CT plots since the establishment of the experimental treatments. Adsorption and degradation were studied in laboratory experiments and solute transport was studied in undisturbed column experiments using non-reactive tracers and herbicides. The results from the column experiments were not significantly different between tillage treatments for Säby and Lönnstorp. For Ultuna, RT resulted in a more pronounced preferential tracer transport pattern and isoproturon leaching was twelve times larger compared to CT columns. This indicates that the tillage treatment had affected the macropore connectivity only at Ultuna. Freundlich adsorption coefficients for both bentazone and isoproturon were larger (though not always significantly) in the top 5 cm of RT soil compared to the 10–20 cm depth and to CT, reflecting the higher organic carbon content. The degradation rate was also generally larger (though not always significantly) in the top 5 cm of RT soil. These results show that RT has the potential to reduce pesticide leaching. However, any such reduction may be counter-balanced by enhanced preferential flow for soils where RT results in improved macropore connectivity. 相似文献
12.
Tillage, mineralization and leaching: phosphate 总被引:2,自引:0,他引:2
Phosphate is usually the limiting nutrient for the formation of algal blooms in freshwater bodies, so tillage practices must minimize phosphate losses by leaching and surface run-off from cultivated land. Mineral soils usually contain 30–70% of their phosphate in organic forms, and both organic and inorganic phosphate are found in the soil solution. Some organic phosphates, notably the inositol phosphates, are as strongly sorbed by soil as inorganic phosphates, and this decreases their susceptibility to mineralization. The strength with which both categories are sorbed lessens the risk of their being leached as solutes but makes it more likely that they will be carried from the soil on colloidal or particulate matter, and the greatest losses of phosphate from the soil usually occur by surface run-off and erosion. Recent studies at Rothamsted have, however, shown substantial concentrations of phosphate in drainage from plots that have long received more phosphate as fertilizer than is removed in crops. These losses probably occurred because preferential water flow carried the phosphate rapidly from the surface soil to the field drains. For lessening losses of phosphate by leaching and run-off, the prime requirement of tillage is that it should encourage flows of water through the soil that help it to retain phosphate. Primary and secondary tillage should ensure that the surface roughness and porosity of the top-soil encourage the flow of water into the soil matrix where it will move relatively slowly and allow phosphate to be sorbed, thereby avoiding problems from run-off and preferential flow. Inversion tillage can be useful for lessening the loss of phosphate by run-off and erosion. Secondary tillage could be used to decrease the size of the aggregates and increase the surface area for sorption. Although tillage will increase the mineralization of organic phosphate, pulses of mineralization are unlikely to be so rapid or to lead to such large losses as with nitrate. The strength with which phosphate is sorbed also lessens the problem. As with nitrate, the key to managing phosphate is basically good husbandry. 相似文献
13.
Solvent extraction characterization of bioavailability of atrazine residues in soils 总被引:4,自引:0,他引:4
Barriuso E Koskinen WC Sadowsky MJ 《Journal of agricultural and food chemistry》2004,52(21):6552-6556
Characterization of pesticide bioavailability, particularly in aged soils, is of continued interest because this information is necessary for environmental risk assessment. The objective of this study was to correlate atrazine residue bioavailability in aged soils, as determined by solvent extraction methods, to atrazine mineralization by an atrazine-degrading bacterium. Webster clay loam and Zimmerman fine sand soils were treated with UL-ring-labeled [14C]atrazine and incubated for up to 8 weeks. At the end of each incubation period, soils were either not extracted, extracted with 0.01 M CaCl2, or extracted with 0.01 M CaCl2/aqueous methanol. Soils were then inoculated with the bacterium Pseudomonas sp. strain ADP, which is capable of rapidly mineralizing the atrazine ring. This allowed for the evaluation of the bioavailability of aged atrazine residues without the contribution of atrazine desorption from soil. Results of these studies indicated that the amounts of atrazine residues in aged soils extracted by 0.01 M CaCl2 and aqueous methanol were correlated to amounts of atrazine mineralized by Pseudomonas sp. strain ADP. Consequently, 0.01 M CaCl2/methanol extractable atrazine in aged soils may be used to estimate bioavailable residues, and this technique may be useful to determine the bioavailability of other compounds in soils, especially other triazine herbicides. 相似文献
14.
Abstract. Uniform application rates of fertilizers and herbicides may result in over-treating some soils and under-treating others; costs may be unnecessarily large and soil, ground water and surface waters may be contaminated. An alternative is site specific treatment, tailored to individual soil types present in agricultural fields of any size. To study the pollution hazards of the herbicide alachlor, leaching and adsorption experiments used disturbed samples and undisturbed soil columns. Adjoining Ves, Normania and Webster soil series (Udic Haplustoll; Aquic Haplustoll; Typic Haplaquoll) were sampled and analysed for various properties. Ring uniformly 14 C-labelled alachlor was used to study adsorption and leaching characteristics in these soils. Results show different alachlor behaviour in topsoil and subsoil layers. 相似文献
15.
Nanoparticles were synthesized from soy protein, one of the most abundant and widely utilized plant proteins, for nutraceutical and drug encapsulation. The preparation process consisted of dispersion, desolvation, drug incorporation, cross-linking, and evaporation. The role of each procedure in the formation of nanoparticles was systematically investigated by means of particle size, size distribution, and zeta potential as well as morphology observation. Curcumin as a model drug was encapsulated successfully into the nanoparticles, evidenced by Fourier transform infrared spectroscopy and X-ray diffraction patterns. The average size of the curcumin-loaded nanoparticles was 220.1 to 286.7 nm, and their zeta potential was around -36 mV. The highest encapsulation efficiency and loading efficiency achieved were 97.2% and 2.7%, respectively. The release of curcumin in phosphate buffer saline followed a biphasic pattern. Possible mechanisms of the formation of soy protein nanoparticles as well as the incorporation of curcumin were discussed based on the data obtained from this study. 相似文献
16.
Jablonowski ND Koeppchen S Hofmann D Schaeffer A Burauel P 《Journal of agricultural and food chemistry》2008,56(20):9548-9554
The long-term behavior of the herbicide atrazine and its metabolites in the environment is of continued interest in terms of risk assessment and soil quality monitoring. Aqueous desorption, detection, and quantification of atrazine and its metabolites from an agriculturally used soil were performed 22 years after the last atrazine application. A lysimeter soil containing long-term aged atrazine for >20 years was subdivided into 10 and 5 cm layers (at the lysimeter bottom: soil 0-50 and 50-55 cm; fine gravel 55-60 cm depth, implemented for drainage purposes) to identify the qualitative and quantitative differences of aged (14)C-labeled atrazine residues depending on the soil profile and chemico-physical conditions of the individual soil layers. Deionized water was used for nonexhaustive cold water shaking extraction of the soil. With increasing soil depth, the amount of previously applied (14)C activity decreased significantly from 8.8% to 0.7% at 55-60 cm depth whereas the percentage of desorbed (14)C residues in each soil layer increased from 2% to 6% of the total (14)C activity in the sample. The only metabolite detectable by means of LC-MS/MS was 2-hydroxyatrazine while most of the residual (14)C activity was bound to the soil and was not desorbed. The amount of desorbed 2-hydroxyatrazine decreased with increasing soil depth from 21% to 10% of the total desorbed (14)C residue fraction. The amount of (14)C residues in the soil layers correlated well with the carbon content in the soil and in the aqueous soil extracts ( p value = 0.99 and 0.97, respectively), which may provide evidence of the binding behavior of the aged atrazine residues on soil carbon. The lowest coarse layer (55-60 cm) showed increased residual (14)C activity leading to the assumption that most (14)C residues were leached from the soil column over time. 相似文献
17.
18.
Bioremediation of atrazine: recent advances and promises 总被引:1,自引:0,他引:1
Purpose
Atrazine is one of the most widely used herbicides to control broadleaf and grassy weeds for many crops in the world. Its contamination has become a growing public concern because atrazine is the most commonly detected pesticide in soil and groundwater. Studies have indicated that atrazine may cause damages to the central nervous system, endocrine system, and immune system. The aim of this review was to update our understanding of recent development of atrazine bioremediation for its improved application.Materials and methods
Bioremediation, an economical and eco-friendly approach, has emerged as the most advantageous technique for cleaning up atrazine contamination in soil and water. A large number of atrazine-degrading bacteria and fungi have been isolated. The genetic pathways for atrazine remediation/detoxification have been well characterized in bacteria, fungi, and plants.Results and discussion
To enhance bioremediation, transgenic microbes and plants expressing atrazine-degrading enzymes have been developed. Co-application of transgenic microbes and transgenic plants has been proposed to get synergistic effect for bioremediation of atrazine.Conclusions
In summary, although effective bioremediation methods of atrazine removal have been successfully employed, it should be noted that there has been a series of disappointing failures, along with tremendous successes in the laboratory. Overall, future research should be geared toward narrowing the gaps between bioremediation in laboratory and environmental applications. 相似文献19.
Farias Christyan Paiva Alves Gabriel Sousa Oliveira Denis Coelho de Melo Edmar Isaías Azevedo Lucas Carvalho Basilio 《Journal of Soils and Sediments》2020,20(1):260-271
Journal of Soils and Sediments - A consortium of fungal isolates may improve phytoremediation by stimulating root growth whereas biochar reduces metal leaching in contaminated soils. We combined... 相似文献
20.
Munoz A Koskinen WC Cox L Sadowsky MJ 《Journal of agricultural and food chemistry》2011,59(2):619-627
Metolachlor (2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)aceto-o-toluidide) is a pre-emergent chloroacetanilide herbicide used to control broadleaf and annual grassy weeds in a variety of crops. The S enantiomer, S-metolachlor, is the most effective form for weed control. Although the degradation of metolachlor in soils is thought to occur primarily by microbial activity, little is known about the microorganisms that carry out this process and the mechanisms by which this occurs. This study examined a silty-clay soil (a Luvisol) from Spain, with 10 and 2 year histories of metolachlor and S-metolachlor applications, respectively, for microorganisms that had the ability to degrade this herbicide. Tis paper reports the isolation and characterization of pure cultures of Candida xestobii and Bacillus simplex that have the ability to use metolachlor as a sole source of carbon for growth. Species assignment was confirmed by morphological and biochemical criteria and by sequence analysis of 18S and 16S rRNA, respectively. High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses indicated that C. xestobii degraded 60% of the added metolachlor after 4 days of growth and converted up to 25% of the compound into CO(2) after 10 days. In contrast, B. simplex biodegraded 30% of metolachlor following 5 days of growth in minimal medium. In contrast, moreover, the yeast degraded other acetanilide compounds and 80% of acetochlor (2-chloro-N-ethoxymethyl-6'-ethylaceto-o-toluidide) and alachlor (2-chloro-2',6'-diethyl-N-methoxymethylacetanilide) were degraded after 15 and 41 h of growth, respectively. The results of these studies indicate that microorganisms comprising two main branches of the tree of life have acquired the ability to degrade the same novel chlorinated herbicide that has been recently added to the biosphere. 相似文献