Herbicide Residues In Soil Research Articles

Rapid residue analysis of four triazolopyrimidine herbicides in soil, water, and wheat by ultra-performance liquid chromatography coupled to tandem mass spectrometry

A sensitive and effective method for simultaneous determination of triazolopyrimidine sulfonamide herbicide residues in soil, water, and wheat was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The four herbicides (pyroxsulam, flumetsulam, metosulam, and diclosulam) were cleaned up with an off-line C18 SPE cartridge and detected by tandem mass spectrometry using an electrospray ionization source in positive mode (ESI+). The determination of the target compounds was achieved in <2.0 min. The limits of detection were below 1 μg kg(-1), while the limits of quantification did not exceed 3 μg kg(-1) in different matrices. Quantitation was determined from calibration curves of standards containing 0.05-100 μg L(-1) with r(2) > 0.997. Recovery studies were conducted at three spiked levels (0.2, 1, and 5 μg kg(-1) for water; 5, 10, and 100 μg kg(-1) for soil and wheat). The overall average recoveries for this method in water, soil, wheat plants, and seeds at three levels ranged from 75.4% to 106.0%, with relative standard deviations in the range of 2.1-12.5% (n = 5) for all analytes.

Changes in Application System - Influence on Herbicides Residue in Soil and Sugar Beet Roots

Changes in Application System - Influence on Herbicides Residue in Soil and Sugar Beet RootsThe aim of performed investigation was to evaluate the influence of changes in herbicide application system on herbicide residues in soil and sugar beet roots. Chemical weed control in sugar beet was carried out by herbicides that included substances such as phenmedipham, desmedipham, ethofumesate, metamitron, triflusulfuron and surfactant adjuvant applied in three different systems: two times application at bare soil (preemergence) and postemergence application (weeds in phase of 2-4 leaves) - system "A", 3 times split, postemergence application (full dose of herbicide mixture) - system "B" and 4 times application at 7 to 10 day intervals starting at the beginning of weed emergence - system "C". Samples of soil and roots of sugar beet were taken at the day of lifting. Herbicide residues were analysed using HPLC with UV-detection. At lifting time, in soil samples, where herbicides were applied in system "A", the residues of metamitron amounted from 0.0097 to 0.0132 mg/kg. Sum of all detected residues of applied substances amounted 0.0341-0.0458 mg/kg. In sugar beet root samples, the residues amounted to respectively, 0.0049-0.0064 and 0.0136-0.0247 mg/kg. The application of herbicides in "B" and "C" systems caused a significant decrease of residues by about 50% (system "B") and 65% (system "C") on average, in comparison with results obtained for herbicide application in "A" system. Residues of active substances determined in roots of sugar beet did not exceed acceptable limits (MRLs).

Sorption–desorption of flucarbazone and propoxycarbazone and their benzenesulfonamide and triazolinone metabolites in two soils

Sorption-desorption interactions of pesticides with soil determine the availability of pesticides in soil for transport, plant uptake and microbial degradation. These interactions are affected by the physical and chemical properties of the pesticide and soil and, for some pesticides, their residence time in the soil. While sorption-desorption of many herbicides has been characterised, very little work in this area has been done on herbicide metabolites. The objective of this study was to characterise sorption-desorption of two sulfonylaminocarbonyltriazolinone herbicides, flucarbazone and propoxycarbazone, and their benzenesulfonamide and triazolinone metabolites in two soils with different physical and chemical properties. K(f) values for all four chemicals were greater in clay loam soil, which had higher organic carbon and clay contents than loamy sand. K(f-oc) ranged from 29 to 119 for the herbicides and from 42 to 84 for the metabolites. Desorption was hysteretic in every case. Lower desorption in the more sorptive system might indicate that hysteresis can be attributed to irreversible binding of the molecules to soil surfaces. These data show the importance of characterisation of both sorption and desorption of herbicide residues in soil, particularly in the case of prediction of herbicide residue transport. In this case, potential transport of sulfonylaminocarbonyltriazolinone herbicide metabolites would be overpredicted if parent chemical soil sorption values were used to predict transport.

Fitorremediação do herbicida trifloxysulfuron sodium

Este trabalho teve como objetivo avaliar a eficiência de espécies vegetais na fitorremediação do herbicida trifloxysulfuron sodium em solos, utilizando o milho como planta indicadora. Os tratamentos foram compostos pela combinação de espécies (Calopogonium muconoides, Crotalaria juncea, Crotalaria spectabilis, Vicia sativa, Cajanus cajan, Canavalia ensiformis, Helianthus annus, Dolichus lablab, Pennisetum glaucum, Stylosantes guianensis, Mucuna deeringiana, Mucuna cinereum, Mucuna aterrima, Raphanus sativus e Lupinus albus), semeadas anteriormente à cultura do milho, mais um tratamento controle (sem cultivo prévio) e três doses do herbicida trifloxysulfuron sodium (0,00; 3,75; e 15,00 g ha-1). O delineamento experimental usado foi o de blocos ao acaso, em esquema fatorial, sendo utilizadas três repetições. A semeadura das espécies vegetais nos vasos foi feita no dia seguinte à aplicação do trifloxysulfuron sodium. Após 80 dias da semeadura, as espécies vegetais foram cortadas na altura do coleto, descartando-se a sua parte aérea. A seguir, foi realizada a semeadura do milho (cultivar AG-122). Aos 45 dias após a emergência das plantas de milho foram avaliadas a altura de plantas e a sua biomassa seca da parte aérea. Verificou-se que as espécies M. aterrima e C. ensiformis foram eficientes na descontaminação do herbicida trifloxysulfuron sodium em solo.

Sorption-desorption of "aged" sulfonylaminocarbonyltriazolinone herbicides in soil.

Sorption-desorption interactions of pesticides with soil determine the availability of pesticides in soil for transport, plant uptake, and microbial degradation. These interactions are affected by the physical and chemical properties of the pesticide and soil, and for some pesticides, their residence time in the soil. The objective of this study was to characterize sorption-desorption of two sulfonylaminocarbonyltriazolinone herbicides incubated in soils at different soil moisture potentials. The chemicals were incubated in clay loam and loamy sand soils for up to 12 wks at -33 kPa and at water contents equivalent to 50 and 75% of that at -33 kPa. Chemicals were extracted sequentially with 0.01 N CaCl(2) and aqueous acetonitrile, and sorption coefficients were calculated. Sufficient sulfonylaminocarbonyltriazolinone herbicides remained (>40% of that applied) during incubation to allow calculation of sorption coefficients. Aging significantly increased sorption as indicated by increased sorption coefficients. For instance, for sulfonylaminocarbonyltriazolinone remaining after a 12-wk incubation at -33 kPa, K(d) increased by a factor of 4.5 in the clay loam soils and by 6.6 in the loamy sand as compared to freshly treated soils. There was no effect of moisture potential on sorption K(d) values. These data show the importance of characterization of sorption-desorption in aged herbicide residues in soil, particularly in the case of prediction of herbicide transport in soil. In this case, potential transport of sulfonylaminocarbonyltriazolinone herbicides would be over-predicted if freshly treated soil K(d) values were used to predict transport.

Determination of Triazine and Chloroacetanilide Herbicides in Soils by Microwave-Assisted Extraction (MAE) Coupled to Gas Chromatographic Analysis with Either GC−NPD or GC−MS

A simple and rapid method based on microwave-assisted extraction (MAE) coupled to gas chromatographic analysis was developed for the analysis of triazine (atrazine, cyanazine, metribuzine, simazine and deethylatrazine, and deisopropylatrazine) and chloroacetanilide (acetochlor, alachlor, and metolachlor) herbicide residues in soils. Soil samples are processed by MAE for 5 min at 80 degrees C in the presence of acetonitrile (20 mL/sample). Mean recovery values of most solutes are >80% in the 10 to 500 microg/kg fortification range with respective RSDs (relative standard deviations) < 20%. The limits of quantification (LOQ) and limits of detection (LOD) are 10 and 1 to 5 microg/kg, respectively. The method was validated with two types of soils containing 1.5 and 3.0% organic matter content, respectively; no statistically significant differences were found between solute recovery values from the two types of soils. The solute mean recovery values from freshly spiked (24 h aging) and spiked samples stored refrigerated for one week before processed were also not statistically different. Residue levels determined in field weathered soils were higher when soils were processed by MAE than with a comparison method based on flask-shaking of soil suspensions overnight. Extracts were analyzed by a gas chromatographic system equipped either with a thermionic (GC-NPD) or a mass spectrometric detector (GC-MS).

Bioassay to Detect MON-37500 and Triasulfuron Residues in Soils1

Sulfonylurea herbicide residues in soil can affect rotational crops even at low concentrations. Although analytical methods are efficient enough to measure them, the lack of an efficient herbicide extraction technique makes bioassays useful for determining the presence of phytotoxic levels of sulfonylurea residues in soil. A growth chamber bioassay using sunflower was developed to detect MON-37500 and triasulfuron residues in two different soils. Root length was measured 15 d after the treatment. A sigmoid equation described plant root length response as a function of herbicide concentration. The nonlinear regression established a range of I50 values from 0.9 to 2.9 ppb ai for both sulfonylureas.Nomenclature: MON-37500 (proposed common name, sulfosulfuron), 1-(4,6-dimethoxypyrimidin-2-yl)-3-[(2-ethanesulfonyl-imidazo[1,2-a]pyridine)sulfonyl]urea; triasulfuron; sunflower, Helianthus annuus L. ‘Albani’.Additional index words: Dose–response curves, I50, phytotoxicity, rotational crops, sulfonylurea herbicides.Abbreviations: I20, dose required for 20% inhibition; I50, dose required for 50% inhibition; OM, organic matter.

ANALYSIS OF A NEW HERBICIDE (PYRIBENZOXIM) RESIDUES IN SOIL USING DIRECT-EXTRACT-INJECTION HPLC WITH COLUMN SWITCHING

A simple and efficient analysis method of the herbicide residues in soil has been developed and applied to residual analysis of a new herbicide, pyribenzoxim. Extraction and separation were performed in sequential mode by on-line column switching. On-line analysis shows better specificity than off-line analysis does. The analyte was well separated without interference and baseline distortion. Recovery yields for standard spiking were 97.9 ± 1 (S.D.) and 92.1 ± 4 (S.D.) % at the concentration of 0.04 and 0.1 ppm in soil, respectively (n=3). The correlation coefficient was greater than 0.999 over the range between 0.1 and 10/mL. The on-line solid phase extraction (SPE) analysis is described, as compared to off-line SPE analysis.

Use of a Particle Beam Interface Combined with Mass Spectrometry/Negative Chemical Ionization to Determine Polar Herbicide Residues in Soil by Liquid Chromatography

The use of mass spectrometry/negative chemical ionization (MS/NCI), in combination with selected-ion monitoring, allows sensitive and selective determination of polar and thermally unstable herbicide residues by liquid chromatography coupled to a particle beam interface. The method has been applied to the analysis of soil samples for herbicide residues, using various procedures for their extraction and employing matrix-standard calibration to avoid quantitative errors due to transfer of matter through the interface. Data for the fragment ions found in the MS/NCI procedure and chromatograms from analyses of real samples are also presented.

Multiresidue Herbicide Analysis in Soil: Subcritical Water Extraction with an On-Line Sorbent Trap

We evaluated the feasibility of extracting selectively and rapidly herbicide residues in soils by hot water and collecting analytes with a Carbograph 4 solid-phase extraction (SPE) cartridge set on-line with the extraction cell. Phenoxy acid herbicides and those nonacidic and acidic herbicides which are often used in combination with phenoxy acids were selected for this study. Five different soil samples were fortified with target compounds at levels of 100 and 10 ng/g (30 ng/g of clopyralid and picloram) by following a procedure able to mimic weathered soils. Herbicides were extracted with water at 90 °C and collected on-line by the SPE cartridge. After the cartridge was disconnected from the extraction apparatus, analytes were recovered by stepwise elution to separate nonacidic herbicides from acidic ones. The two final extracts were analyzed by liquid chromatography/mass spectrometry with an electrospray ion source. At the lowest spike level considered, analyte recoveries ranged between 81 and 93%, except those for 2,4-DB and MCPB, which were 63%. For 16 herbicides out of 18, the ANOVA test showed recoveries were not dependent on the type of soil. The method detection limit was in the 1.7-10 ng/g range. For the analytes considered, method comparison showed this extraction method was overall more efficient than Soxhlet and sonication extraction techniques.

Fate and behaviour of triasulfuron, metsulfuron-methyl, and chlorsulfuron in the Australian soil environment: a review

The sulfonylurea herbicides comprise a group of compounds designed to control broad-leaved weeds and some grasses in a variety of crops. The herbicides have become popular because of their low application rates (10-40 g/ha), low mammalian toxicity, and unprecedented herbicidal activity. We present a review of the fate and behaviour of these herbicides in soils with particular reference to alkaline soils of Australia. The review shows that the low application rates of sulfonylurea herbicides continue to present an analytical challenge, although in recent years a number of new methods capable of detecting them at very low concentrations have been developed. A range of analytical methods is available, including high performance liquid chromatography, gas chromatography, immunoassay, and bioassay. However, analytical sensitivity required to detect trace levels of these herbicides continues to pose problems in routine detection of herbicide residues in soils. The review reveals that there are no reports of studies of the behaviour of sulfonylureas in soils with pH &gt;8·2. This is of particular significance to Australian conditions because a number of Australian soils are even more alkaline, and the pH(water) in subsoils can be as high as 10· 2. Sorption of sulfonylureas is pH-dependent and has a strong negative correlation with pH. At pH &gt;8·0 sorption is very low. In acid soils, however, sorption of chlorsulfuron, metsulfuron-methyl, and triasulfuron is strongly influenced by the soil temperature, clay content, and, particularly, organic matter content. The principal modes of degradation of the herbicides are acid hydrolysis and microbial degradation with the latter being the only major pathway in alkaline soils. Hydrolysis of the sulfonylureas is more rapid under acidic conditions (pH 4{7), and the data suggest that hydrolysis is likely to be very slow in alkaline soils. Data from other countries suggest that the half-life of chlorsulfur on increases exponentially with pH, and that it is also influenced by variations in the temperature and water content of the soil. Being acidic in nature, the herbicide molecules become anionic at high pH and can move to a considerable depth in the soil profile by leaching. Movement of the sulfonylureas in soil is largely influenced by organic matter content and soil pH and the reviewed data show that sulfonylureas have substantial leaching potential in the sandy alkaline soils of Australia. This is likely to result in increased persistence in alkaline subsoils lacking in organic matter and biological activity. Computer models to predict the persistence and movement of the sulfonylureas are available; however, additional input parameters are required to predict accurately the behaviour of specific herbicides in alkaline soils under Australian conditions. Since new herbicides with chemistry similar to existing sulfonylureas are increasingly likely to be available for use, there is a need to develop comprehensive understanding of their fate, behaviour, and impact on Australian cropping and ecological systems.

A new radiorespirometric method for measuring herbicide residues in soil: 2,4-D as a test case

In this paper we describe the principles of an analytical procedure based on radiorespirometric measurements that could be applied to the determination of residual concentrations of 2,4-D in the soil. Basically, it consists of comparing, in two soil samples, mineralization of 2,4-D, labeled at two different specific activities. The validity of the procedure depends on the concentration of herbicide, the location of the radioactive carbon within the molecule and the possibility to distinguish several phases in the evolution of 14CO 2. The dosage has been proved more reliable at concentration levels that are consistent with agricultural practice than at lower concentrations. We also demonstrate that an appropriate mathematical treatment of the experimental data makes it possible to indentify the fraction of the mineralized radioactivity that specifically originates in the degradation of 2,4-D. This allows more realistic estimates of the amount of the parent molecule left unchanged in the soil by reducing interference by 14C-containing residuals resulting from microbial activity. We also demonstrate that carboxylic and methylenic carbon atoms of the side-chain are not assimilated with an equal efficiency. The absence of a true lag-phase indicates that the soil we have used contains a microbial population that degrades 2,4-D without requiring a preliminary period of adaptation.

Survey of herbicide residues in soil and wells in three citrus orchards in Valencia, Spain

Summary: Soil samples taken in summer 1989 and winter 1990 at different depths from three citrus orchards of the Valencia region (Spain) with a long history of residual herbicide treatments were analysed with bioassays and chromatographic procedures. The herbicides involved were atrazine, bromacil, diuron, simazine, terbuthylazine, terbumetone, terbutryn and trifluralin. Water samples from wells in the orchards were also analysed. The concentrations of the herbicides were very low, often below the limit of determination, and were always highest in the upper layers of soil. After a very unusual period of heavy rain, small quantities of some chemicals were found in the well water. The conclusion was that in these orchards the herbicides applied at currently used rates are unlikely to accumulate in any layers of the soil. Resume: Des echantillons de sol ont ete proves a differentes profondeurs dans 3 vergers d'agrumes de la region de Valence (Espagne), lors de l'ete 1989 et de l'hiver 1990. Ces sols avaient tous un lourd passe de traitements herbicides residuaires; ils furent analyses selon des procedures de chromatographie et d'essais biologiques. Les herbicides interesses ont ete: atrazine, bromacile, diuron, simazine, terbuthylazine, terbumetone, terbutryne et trifluraline. On a aussi analyse des echantillons d'eau provenant de puits situes dans les vergers. Les concentrations des herbicides ont ete tres basses et souvent inferieures a la limite de determination de la methode d'analyse. Elles ont ete systematiquement plus elevees dans les couches superieures du sol. Apres une periode de fortes pluies exceptionnelles, des petites quantites de certains herbicides ont ete trouvees dans l'eau des puits. En conclusion, les herbicides appliques dans ces vergers aux doses couramment utilisees ne sont vraisemblablement pas susceptibles de s'accumuler dans aucune des differentes couches de sol. Zusammenfassung: Bei der Analyse von im Sommer 1989 und Winter 1990 verschieden tief entnommenen Boden- und Brunnenwasserproben aus 3 Citrus-Plantagen um Valencia, die seit langerer Zeit mit persistenteren Herbiziden (Atrazin, Bromacil, Diuron, Simazin, Terbuthylazin, Terbumeton, Terbutryn und Trifluralin) behandelt worden waren, lag deren Konzentrationen sehr niedrig, oft unter der Nachweisgrenze (Biotests und Gaschromatographie); in den oberen Bodenschichten waren sie immer am hochsten. Nach einer Periode ungewohnlich heftiger Niederschlage wurden geringe Mengen einiger Chemikalien im Brunnenwasser gefunden. In diesen Obstanlagen fuhrt der normale Aufwand von Herbiziden offensichtlich zu keinen erhohten Ruckstanden im Boden.

Determination of herbicide residues in soil in the presence of persistent organochlorine insecticides

A rapid and reproducible gas-chromatographic method has been developed for determination of residues in soil of some widely used herbicides such as trifluralin, metribuzin, alachlor, acetochlor, metolachlor, pendimethalin, simazine, atrazine, prometryne, in the presence of persistent organochlorine insecticides (p,p-DDT, o,p-DDT, p,p-DDE, alpha-HCH, gamma-HCH, heptachlor). Determination of some herbicides by GC/ECD is difficult since their relative retention times on packed columns usually used for pesticide analysis are equal or close to those of some persistent organochlorine insecticides which can still be found almost everywhere, especially in cultivated soils. A 1.8 m column of 3% OV-225 + 5% SE-52 in a ratio of 1.4:0.9 gave good separation of all herbicides and insecticides mentioned. The influence of 6 solvents and solvent systems applied most frequently for soil extraction of pesticide residues on recovery of the compounds under study was examined. Acetonitrile was the most suitable extractant as it rendered highest residue recoveries and minimal amount of co-extractives. Residues of simazine, atrazine, and prometryne were determined in the same extracts by the use of NP-detector and a column of 5% Carbowax 20M. Recoveries of the compounds under study were in the interval of 86–103% without cleanup and 78–94% when cleanup was carriet out. The method can be used in pesticide monitoring of soil as it offers an opportunity for rapid determination of soil applied herbicides and persistent organochlorine insecticides which are some of the most common pollutants in cultivated soils.

High-performance liquid chromatographic method for determining triazine herbicide residues in soil

The extraction of eight triazines from soil and their isolation from the soil extract were simultaneously performed using two mini-columns connected in series, one containing the soil sample and the other filled with a strong acid exchanger. By allowing 3 ml of acetone to flow along the two cartridges in tandem, triazines were removed from the soil particles and then selectively readsorbed via salt formation on the exchanger surface. After disconnecting the two cartridges, the triazines were eluted from the exchanger trap by potassium chloride-saturated methanol. This procedure was also adopted to desorb from the soil surface residual amounts of chemically adsorbed triazines, which acetone is unable to remove. After removal of methanol from the two combined eluates, the triazines were fractionated and quantified by reversed-phase high-performance liquid chromatography with UV detection at 220 nm. Using this procedure, the recoveries of triazines were greater than 90% and independent of the triazine concentration, the type of soil samples and their ageing on storage. The mean limit of detection was about 1 ng/g in soil. The results obtained were compared with those obtained by two techniques of known efficiency (reflux extraction and Soxhlet extraction). Some effects on the adsorption of triazines of the type of soil and its ageing on storage are discussed.

Detoxification of Herbicide Residues in Soil

Much of the success of modern agriculture is due to pesticide technology. Because weeds pose the greatest threat to crop yields, the largest class of pesticides used today is herbicides. Herbicides include products whose active ingredients represent a wide range of chemical families; yet most constitute a minimal potential hazard to man and the environment. Criteria typically used to determine potential hazard are mammalian and piscine toxicity, persistence, and bioaccumulation. By evaluating these criteria and assigning numerical values it is possible to devise a ranking of pesticides such as that developed by Weber (51). This list identifies those pesticides most likely to have some undesirable activity, either before or after they are applied. All herbicides ranked well below organochlorine insecticides in hazard rating and most were less hazardous than the organophosphate and carbamate insecticides. However, any substance, when used improperly, has the potential to cause problems, and for this reason all chemicals should be handled with caution.

Determination of acid and hydroxybenzonitrile herbicide residues in soil by gas-liquid chromatography after ion-pair alkylation

The herbicides are extracted from soil with saturated calcium hydroxide solution. After clean-up the residues are ethylated using iodoethane and tetrabutylammonium hydrogen sulphate as counter ion. Liquid-liquid partition and the use of a macroreticular resin column were compared as clean-up steps and the reaction conditions for optimum yield of ethyl ester or ether were evaluated. Recoveries in excess of 80% were achieved for 2,4-D, dicamba, 3,6-dichloropicolinic acid, dichlorprop, picloram, 2,4,5-T, fenoprop, 2,3,6-TBA, bromoxynil and ioxynil.

Availability to plants of herbicide residues in soil. Part I: A rapid method for estimating potentially available residues of herbicides

Summary:A simple extraction method with water is described which allows the quantitative determination, within 1 day of the residues of soil‐applied herbicides which are potentially available to plants. The validity of this method has been examined with a growth test using Brassica rapa in soils containing residues of different ages.

Availability to plants of herbicide residues in soil. Part II: Data for use in vegetable crop rotations

Summary:The response of a variety of vegetable crops to fifteen herbicides was estimated in culture solution over concentration ranges chosen to correspond with those that might occur in soil solution. Examples are given to show how these results can be used, in conjunction with the method for estimating the available herbicide residues (in Part I), to decide which crops may safely be sown in soil containing a herbicide residue.

A Residue Technique for Urea Herbicides Using Catalytic Hydrolysis on Silica Gel Plates

Abstract Urea herbicides are catalytically hydrolyzed to the corresponding aniline. The reaction occurs in situ on silica gel TLC plates making use of the acidic silanol groups. The anilines are then further reacted in situ with dansyl chloride and the fluorescent derivatives separated on the same plate. The sensitivity and selectivity of this technique permit the analysis of urea herbicide residues in soil and water samples with good reproducibility and a minimum of sample clean-up.