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Determination of herbicides residues in soil by small scale extraction
Abstract
Herbicides such as trifluralin, simazine, atrazine, metribuzin and metolachlor are used in Brazilian agriculture. The efficiency of a small scale method for determination of these herbicides and two degradation products (deisopropylatrazine and deethylatrazine) in soil samples was evaluated. The compounds were extracted from soil samples (5 g) with 20 ml of ethyl acetate in a mechanical shaker for 50 min. Following the extraction, the supernatant was dried through anhydrous sodium sulphate, concentrated and analysed by high resolution gas chromatography (HRGC) with thermionic specific detection (TSD). Mean recoveries obtained from soil samples fortified at three different levels ranged from 81 to 115% with relative standard deviation (RSD) values varying from 1.2 to 12.7%. The method detection limits ranged from 0.01 to 0.06 mg kg-1. The methodology was applied using soil samples from farms located near the town of Araraquara, in the State of São Paulo, Brazil.
... Currently, two methods are predominantly used for the determination of the present pesticide content in environmental samples, namely high-pressure liquid chromatography (HPLC) and gas chromatography (GC), which use specific detectors for certain groups of chemical compounds. Regarding the analytical methods for the determination of herbicide content in various materials (water, soil, plants, animal tissue etc.) [16][17][18][19], the investigation procedure can be reduced to the isolation of the herbicide by means of solvent extraction. This is followed by purification of the obtained solution and its standardization and final determination. ...
The decomposition of seven herbicides (atrazine, linuron, lenacil, chloridazon, dinoseb acetate, prometryn, and diuron) was carried out by detonative combustion. The investigated blasting material was produced on the basis of porous ammonium nitrate, which served as an oxidizer, while the pesticides played the role of the fuel. Detonative decomposition of the mixtures was carried out in blast-holes in soil. The efficiency of the decomposition process was assessed using the techniques of gas chromatography, high-efficiency liquid chromatography, and additionally by biological tests according to the grading of the European Weed Research Council. The results demonstrate an efficient decomposition of the tested herbicides. In the tested soil samples taken after the detonation decomposition of the herbicide, no symptoms of phytotoxic effects on the plants were found. This was confirmed by the lack (or at most negligible amounts) of residual herbicides in the soil samples. Only for the samples of chloradizine and diuron were large amounts of residual biologically active substance found.
... Experimental design A = 50g of untreated soil sample only (negative control) B = 50g of untreared sterilized soil sample with to which is seeded 10ml broth culture of mixed culture of Pichia kudriavzevii, Hanseniaspora opuntiae and Pichia cecembensis MT566876 (natural attenuation-positive control) C = 10ml broth culture of Pichia kudriavzevii MT366877was seeded into 50g of sterilized soil sample containing 50ml of 50mg/l paraeforce D =10ml broth culture of Hanseniaspora opuntiae MT366875was seeded into 50g of sterilized soil sample containing 50ml of 50mg/l paraeforce E = 10ml broth culture of Pichia cecembensis MT566876 sp seeded into 50g of sterilized soil sample containing 50ml of 50mg/l paraeforce F = 10ml broth culture of mixed culture of Pichia kudriavzevii, Hanseniaspora opuntiae and Pichia cecembensis MT566876 seeded into 50g of sterilized soil sample containing 50ml of 50mg/l paraeforce. Soil extraction on the treated soil was done using the method of Polese (2002). oxalate was determined using the methods described by Munir,et al (2001) and Vishal et al. (2014) while formate was determined using the method of (Denning et al, 2015) . ...
... Soil samples were collected at the same locations as water samples in March and July of 2017 and 2018. The samples were collected to a depth of 50 cm at intervals of 0-10, 10-20, 20-30, 30-40 and 40-50 cm following [43] using a soil auger. Soil samples were mixed at each depth to form one composite sample. ...
This study investigated the impacts of cultivation on water and soil quality in the lower uMfolozi floodplain system in KwaZulu-Natal province, South Africa. We did this by assessing seasonal variations in purposefully selected water and soil properties in these two land-use systems. The observed values were statistically analysed by performing Student’s paired t-tests to determine seasonal trends in these variables. Results revealed significant seasonal differences in chloride and sodium concentrations and electrical conductivity (EC) and the sodium adsorption ratio (SAR) with cultivated sites exhibiting higher values. Most of the analyzed chemical parameters were within acceptable limits specified by the South African agricultural-water-quality (SAWQ) water quality guidelines for irrigation except for sodium adsorption ratio (SAR), chloride, sodium and EC. EC, pH and nitrate content which were higher than the specified SAWQ limits in cultivated sites. Quantities of glyphosate, ametryn and imidacloprid could not be measured because they were below detectable limits. The study concludes that most water quality parameters met SAWQ’s standards. These results argue for concerted efforts to systematically monitor water and soil quality characteristics in this environment to enhance sustainability by providing timely information for management purposes.
... Soil extraction on the treated soil was done using the method of Polese (2002) and the rate of paraeforce degradation determined using the method described by Okpokwasili and Nwosu (1990). ...
Onianwah, F. I¹.; Eze, V. C¹.; Ifeanyi¹, V. O.; Stanley, H.O². The aim of the research is explore the biodegradation potential of yeast on paraeforce impacted soil and the analysis of the associated enzymes and metabolites. Soil sample was collected from an agrarian soil previously exposed to paraeforce herbicide. Physicochemical analysis was done on the soil sample. Fungal isolation was done using traditional plate culture and molecular techniques. The biodegradation potential of the isolates was determined using titrimetric method. The physicochemical analysis of the treated soil sample recorded a pH of 6.96, temperature (33 0 C), moisture content (71.8%), nitrate (25.6mg/kg), total organic carbon (42mg/kg), biochemical oxygen demand (5.68mg/kg), and conductivity (4.236µscm-1). Yeasts isolated from the soil sample were Pichia kudriavzevii MT366877, Hanseniaspora opuntiae MT366875, Candida. These yeasts were able to degrade the paraeforce. There was a synergy in the degradative activity of the mixed culture. At the end of 90 days, paraeforce degradation was significant in Pichia kudriavzevii MT366877 (27.5mg/kg), Hanseniaspora opuntiae MT366875 (22.4mg/kg) and Pichia cecembensis MT366876 (23.1mg/kg). Natural attenuation recorded a degradation rate of 41.37mg/kg in 90 days. When the sample was optimized using poultry wastes, the degradation rate improved. The mixed culture achieved 100% (50mg/kg) degradation of paraeforce in 56 days. Natural attenuation achieved 100% degradation in 70 days. Pichia kudriavzevii MT366877, Hanseniaspora opuntiae MT366875 and Pichia cecembensis MT366876 recorded 36.7mg/kg, 29.5mg/kg and 26.08mg/kg respectively at the end of 90 days. The growth of fungi was influenced by pH, temperature, nitrate, total organic carbon and the biochemical oxygen demand of the growth medium. The research showed that living cells of the yeasts have great potential for the degradation of paraeforce in an impacted soil and may be used bioremediation of impacted soil.
... Extraction of atrazine from soil samples: Extraction of Atrazine from soil was carried out using the method described by Polese et al., [27]. Extraction took place by adding 150 ml ethyl acetate (to give the high percentage recovery) to 50 g soil sample in a conical flask with 20 g sodium sulfate anhydrous. ...
Abstract
In a previous study by the authors, toxicity screening of Atrazine-resistant soil bacteria from different contaminated soils resulted in 23-soil isolate best grown in the presence of herbicide Atrazine. They were identified according to their 16S rDNA sequencing into Enterobacter (E. cloacae), Bacillus (B. cereus and B. anthracis),
Pseudomonas (P. aeruginosa, P. balearica, P. indica and P. otitidis), Ochrobactrum (O. intermedium) and
Providencia (P. vermicola). The 23 resistant isolates were enriched in nutrient broth medium amended with 2 folds the recommended dose (RD) of Atrazine. The enrichment technique resulted in the selection of seven bacterial species belong to 4 genera (Enterobacter, Pseudomonas, Bacillus and Providencia) that were superior in their resistance to Atrazine and exhibited remarkable growth stimulation (70.7-88.7%). These four acclimatized and highly Atrazine-resistant strains have been selected and efficiently used for the degradation of Atrazine-contaminated soil. They were employed in different proposed bioremediation technologies including biostimulation (addition of nutrients to enhance the growth and activity of the indigenous microorganisms), bioaugmentation (seeding the most promising indigenous and exogenous Atrazine degraders to accelerate and help the indigenous bacterial population to achieve high and fast remediation of the contaminated soil) and finally a combination of biostimulation and bioaugmentation technologies to investigate the synergistic or suppressive effects of the two techniques. Results proved that bioaugmentation coupled with biostimulation is the most promising bioremediation technology since it is powerful, economical and environmentally friendly technique for decontamination of Atrazine-contaminated soils.
A sensitive, rapid, cheap and ecologically safe analytical method has been developed for simultaneous quantification of nine dinitroaniline herbicides (ethalfluralin, trifluralin, benfluralin, profluralin, fluchloralin, isopropalin, pendimethalin, nitralin, prodiamine) in environmental samples, namely surface water, soil and food (tomato) matrices. Vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) sample preparation and gas chromatography coupled with tandem mass spectrometry (GC–MS/MS) enabled simultaneous quantification of the nine dinitroaniline herbicides in as little as 20 min. The effects of different variables on the DLLME procedure were evaluated, including the type and volume of disperser solvent, the volume of chloroform as the extractant solvent, and extraction time. An optimal analyte protectant mixture (0.5, 1, and 1 mg/mL D-sorbitol, shikimic acid, and δ-gluconolactone, respectively) was identified and employed to improve the detection sensitivity for the tested analytes; this mixture was added to the standards in solvent and used instead of matrix-matched calibration curves during quantification. The selectivity, linearity, precision and accuracy of the proposed methodology were validated: the correlation coefficients were > 0.99 and the limits of detection ranged from 0.3 to 3.3 µg/L for the tested analytes. The limits of quantification (LOQ) ranged from 0.4 to 2 µg/kg in surface water and 2 to 10 µg/kg in soil and tomato samples. Percentage recovery at the LOQ ranged from 64.1 to 87.9%, with inter-day repeatability of ≤ 15.1%. The proposed method was also used to monitor the target analytes in real samples.
The extensive use of pesticides leads to soil contamination and is harmful to environmental health. Brazil is considered the world's largest consumer of pesticides; however, there is no published review of the distribution and concentration of pesticides in the Brazilian soils. Thus, the objective of this study was to analyze the occurrence of pesticide residues in Brazilian soils through a systematic review of the data obtained from the official records of government agencies and scientific literature. Further, this review aims to estimate the risk quotient using the data extracted from these studies and compare it with the values from current legislation. The studies on pesticides were selected and screened, out of which 21 scientific articles were included in this review. The studies highlighted that 55 pesticides were detected in the soils in Brazil. Of these, 58% belonged to the chemical class of organochlorines and their concentration ranged from 0.0002–1243.68 mg/kg. DDT (0.00002–1243.68 mg/kg), HCH (0.00007–962.00 mg/kg) and Diuron (0.0031–4.16 mg/kg) contributed to highest pesticide concentrations in soil. Residential soils had higher pesticide concentrations and greater risk factors than the agricultural soils. Moreover, 20% of the studies detected mixtures containing more than 10 types of pesticides. This study concluded that the specific scenarios evaluated by the reviewed studies do not reflect the current pesticide use and contamination in Brazil and there is a need for more information related to pesticide contamination in soils.
Modern agriculture depends to a large degree on the use of herbicides in order to cotrol weeds that compete with the crops. Herbicides are widely used in agricultural crops to control weeds they may produce important yield reductions. The introduction of these pesticides in the food chain via the environment can be considered a risk for human health due to the toxicity of the most of these compounds. In the last years, new extraction procedures have been developed to overcome the drawbacks caused by using high amounts of glassware and toxic solvents in the classical liquid extraction methods. The newest results in the use of various extraction techniques and chromatographic methods such as high-performance liquid chromatography and gas-chromatography mass spectrometry used for the assessment of herbicide residue in various matrices have been compiled an critically evaluated.The objectives of these review are the concise enumeration of the chromatographic separation methods used for the determination of herbicide residue in various organic and anorganic matrices, and the compilation and critical evaluation of the most meaningful results. The contamination of soil, surface and ground water with pesticides from agriculture applications is a major problem. Herbicides represents about 50% of the demand for agricultural chemicals and are applied directly or indirectly to increase crop yields. Herbicides protect crops from undue competition from weeds and enhance the nutrion quality of food. Their prolonged use involves the risk of their retention and accumulation not only in soil and crops, but also in ground and agricultural waters, so the analysis of these compounds has become an important part of water and soil monitoring programmes. The main chemical classes of herbicides include triazine derivates containing three heterocycle nitrogen atoms in the ring structure (atrazine, prometryn, metribuzyn etc.), clorophenoxy acid derivates (2,4 – D etc.), substituted chloroacetanilides (alachlor, propachlor etc.), urea derivates, substituted sulphonylureas (amidosulfuron, nicosulfuron, etc.). Because of the wide variety of molecular structures of herbicides, the development of a considerable number of chromatographic separation methods was necessitated for their successful analysis.
Pesticide use is an important component of agricultural and non-agricultural pest control in tropical areas. However, the fate of pesticides in tropical soils is not as well understood as that for soils from temperate regions. Tropical soils defy easy generalizations, but they are typically very old soils characterized by year-round uniformity of temperature regime. Although only a few studies have directly compared pesticide fate in tropical and temperate soils, there is no evidence that pesticides degrade more slowly under tropical conditions. Laboratory studies in which soils have been held under standardized conditions reveal that pesticide degradation rate and pathway are comparable between tropical and temperate soils. However. field investigations of tropical pesticide soil fate indicate that dissipation occurs more rapidly, in some cases much more rapidly, than for pesticides used under similar temperate conditions. The most prominent mechanisms for this acceleration in pesticide dissipation appear to be related to the effect of tropical climates, and would include increased volatility and enhanced chemical and microbial degradation rates on an annualized basis.
Atrazine was extracted from two weathered soil samples with the proposed micro extraction method using ethyl acetate as the extracting agent. The results were compared with other extraction methods tested. The proposed micro method was equally effective as the micro on-line method using acetone for the extraction and more effective than the Soxhlet extraction using acetone and methanol. Therefore, the proposed micro ethyl acetate method can be used for routine analysis.
Pesticide use is an important component of agricultural and non-agricultural pest control in tropical areas. However, the fate of pesticides in tropical soils is not as well understood as that for soils from temperate regions. Tropical soils defy easy generalizations, but they are typically very old soils characterized by year-round uniformity of temperature regime. Although only a few studies have directly compared pesticide fate in tropical and temperate soils, there is no evidence that pesticides degrade more slowly under tropical conditions. Laboratory studies in which soils have been held under standardized conditions reveal that pesticide degradation rate and pathway are comparable between tropical and temperate soils. However, field investigations of tropical pesticide soil fate indicate that dissipation occurs more rapidly, in some cases much more rapidly, than for pesticides used under similar temperate conditions. The most prominent mechanisms for this acceleration in pesticide dissipation appear to be related to the effect of tropical climates, and would include increased volatility and enhanced chemical and microbial degradation rates on an annualized basis.
A method for the quantitative estimation of atrazine and its principal degradation products in agricultural soils and associated surface and ground water is described. Bonded-phase extraction through eyclohexyl cartridges is used to isolate two principal degradates of atrazine from both surface and ground water samples. Soil is first extracted with organic-free water followed by dilute hydrochloric acid under heated conditions in a microwave extraction system. Reversed-phase HPLC employing an acetonitrile-water gradient is used for separation of analytes on a stabilized Gig analytical column. Analytes are detected by monitoring multiple wavelengths using a photodiode array detector. Identification is by retention time and molecular absorption spectra matching against reference standards. Terbuthylazine serves as a surrogate analyte. Method validation involved determination of percentage recovery for all analytes from fortified soil material and from spiked water. Amendment levels ranged from 0.10 to 10.0 μg/L for water and from 100 to 10 000 μg/kg for soils. Nominal limit of detection is 0.4 μg/kL for water and 40 μg/kg for soils.
Simultaneous determination of several dinitroaniline herbicides in environmental samples (soil, plant and air) was performed by gas chromatography with ion trap and nitrogen-phosphorus detection.Soil was extracted with ethyl acetate on an orbit shaker and plants were extracted with methanol in a Sorvall homogenizer. The plant extract was purified on a Florisil column before gas chromatographic analysis. The dinitroaniline herbicides volatilized from soil were trapped on a Florisil column, eluted with acetone and then analyzed by gas chromatography.The concentrations of these compounds were determined by gas chromatography with nitrogen-phosphorus detection on a HP-1 capillary column and with ion trap detection on a BP-1 capillary column. Helium was used as carrier gas.In all cases, the average recoveries were higher than 75%. The limit of detection for these herbicides was, at least, 0.01 μg/g in soil, 0.05 μg/g in plant and 1 ng/l in air with both gas chromatographic methods.
An analytical method which, permits the determination of the chlorotriazine herbicides Atrazine, Cyanazine and Simazine, their dealkylated degradation products Deethylatrazine and Deisopropylatrazine and the organophosphorus pesticides Fenitrothion and Tetrachlorvinphos in soil samples in the ppb range (0.5–100 ng/g) is described. Two clean up procedures involving Florisil column chromatography and gel permeation chromatography with Bio-Beads SX-3 packing material have been compared for reducing the interferences from the soil matrix. The recoveries varied from 75 to 10316% depending on the compound, and clean up method. Analysis have been carried out by gas chromatography with nitrogen/phosphorus detection and liquid chromatography with diode array detection. Advantages and limitations of both techniques are discussed. Gas chromatography-mass spectrometry in the electron impact mode and thermospray liquid chromatography-mass spectrometry in the positive ion mode have been employed as confirmatory characterization techniques. The methodology has been validated by analyzing residue levels of Atrazine, Deethylatrazine and Fenitrothion in real soil samples which varied from 0.02ng/g up to 10g/g, depending on the period of application and pesticide use.
Our multimethod enables the determination of pesticides adsorbed on soil particles up to 0.5 g/kg soil with recovery rates greater than 80%.
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.
Analytical techniques are essential for identifying and quantifying the chemicals present in environmental samples. A method for extracting pesticides from soil leachates was developed. The proposed method is based on solid-phase extraction and uses 47-mm disks of octyl-bonded silica. Analysis was carried out by gas chromatography with nitrogen-phosphorus and electron-capture detectors. Several factors that can provide better pesticide recoveries with this extraction method are discussed. These factors are: the kind and percentage of organic solvent used in the extraction procedure, the volume and the ionic strength (adding 15% of NaCl) of the aqueous phase which passes through the octyl-bonded silica sorbent, Finally, the proposed method was used to determine the pesticide concentration of leachates from soil samples taken from different plots of an important intensive agricultural area. (C) 1997 Elsevier Science B.V.
The effects of various parameters on supercritical fluid extraction (SFE) of triazines from soil were studied with an experimental design, based on multiple linear regression. The SFE was performed using a multi-extraction unit with simultaneous extraction of eight samples. Different types of soil samples were spiked with a series of five triazines with different polarities.The developed design was a compromise of various objectives like the relative importance of the different parameters, the total amount of experiments and instrumental limitations. Eleven series of experiments using different conditions were performed, resulting in a data set of over 200 data. Regression analysis was applied to evaluate the data set of each individual triazine component. Furthermore, the influence of the different parameters was tested, resulting in a limitation of the original parameter set as well as a combination of some parameters to avoid interactions. The influence of the pressure on the recovery appeared to be very important, recoveries increased with increasing pressures. The influence of the modifier was also essential, only when it was added directly to the extraction cell, and the effect is increasing with component polarity. The effects of the temperature and extraction time were slightly negative and not significant, whereas a small effect of the type of soil was observed. Two other models, combining the whole data set for all triazines, were applied resulting in a more pronounced effect of the individual parameters.Multiple linear regression appeared to be a useful tool to study the effects of the many parameters in SFE, in order to reduce the number of experiments, to facilitate the evaluation of data and to distinguish possible interactions between several parameters.
Pesticide fate in tropical soils
- RACKE K.D.