Radiolytic degradation of malathion and lindane in aqueous solutions

Degradation of malathion and lindane pesticides present in an aqueous solution was investigated on a laboratory scale upon gamma-irradiation from a ⁶⁰Co source. The effects of pesticide group, presence of various additives and absorbed dose on efficiency of pesticide degradation were investigated. Gamma-irradiation was carried out in distilled water solutions (malathion and lindane) and in combination with humic solution (HS), nitrous oxide (N₂O) and HS/N₂O (lindane) over the range 0.1–2 kGy (malathion) and 5–30 kGy (lindane). Malathion was easily degraded at low absorbed doses compared to lindane in distilled water solutions. Absorbed doses required to remove 50% and 90% of initial malathion and lindane concentrations in distilled water solutions were 0.53 and 1.77 kGy (malathion) and 17.97 and 28.79 kGy (lindane), respectively. The presence of HS, N₂O and HS/N₂O additives in aqueous solutions, significantly improved the effectiveness of radiolytic degradation of lindane. Chemical analysis of the pesticides and the by-products resulted from the radiolytic degradation were made using a gas chromatography associated with mass spectrometry (GC–MS). Additionally, the final degradation products of irradiation as detected by ion chromatography (IC) were acetic acid and traces of some anions (phosphate and chloride).     

Evaluation of a modified QuEChERS method for the extraction of pesticides from agricultural, ornamental and forestal soils

A modified version of the QuEChERS method has been developed for the determination of a group of ten organophosphorus pesticides (i.e. ethoprofos, dimethoate, diazinon, malaoxon, chlorpyrifos-methyl, fenitrothion, malathion, chlorpyrifos, fenamiphos and phosmet) and one thiadiazine pesticide (buprofezin) in three different types of soils (forestal, ornamental and agricultural). The method was validated through linearity, recovery, precision and accuracy studies, and also by carrying out a matrix-matched calibration for the three soils owing to the existence of a strong matrix effect. Acceptable recovery values were obtained (between 45 and 96%) for all the pesticides and soils, except for malathion and malaoxon in forestal and ornamental soils, from which they could not be quantitatively extracted. Limits of detection of the whole method ranged between 0.48 and 7.78 ng/g. The method was finally applied to the determination of chlorpyrifos concentration in a treated soil for cultivation of potatoes.     

Application of nanoperlite as a new natural sorbent in the preconcentration of three organophosphorus pesticides by microextraction in packed syringe coupled with gas chromatography and mass spectrometry

A rapid, low‐cost, and simple method is proposed based on a miniaturized solid‐phase extraction named microextraction in packed syringe coupled with gas chromatography and mass spectrometry for the preconcentration and determination of some organophosphorous pesticides including diazinon, ethion, and malathion. For the first time, natural nanoperlite is used as a safe sorbent. Based on this technique, the analytes are adsorbed on the solid phase and then eluted by a desorbing solvent. The influence of some important parameters such as the solution pH, type, and volume of the organic desorption solvent on the microextraction efficiency of the selected pesticide technique is investigated. The proposed method showed a good linearity in the range of 1.0–35.0 μg/L for ethion and 0.4–30.0 μg/L for both diazinon and malathion. The limits of detection in the range of 0.1–0.38 μg/L were obtained using the selected ion‐monitoring mode of the mass spectrometer. The reproducibility of the method was found to be in the range of 2.8–8.9% for the studied pesticides. To evaluate the matrix effect, the developed method is also applied to the preconcentration and determination of the selected pesticides in real water samples.     

De-contamination of pesticide residues in food by ionizing radiation

The role of gamma irradiation on removal of pesticides in aqueous solutions or in vegetables and fruits was investigated. Radiation - induced decontamination of pesticides is generally greater in aqueous solutions than in selected vegetables and fruits. Residues of malathion (0.5 ppm in potatoes, 8 ppm in onions and dates), pirimiphos-methyl (1 ppm in onions and grapes) and cypermethrin (0.05 ppm in potatoes and 0.1 ppm in onions) were not reduced to below maximum residue limits (MRLs) for irradiation doses up to 1 kGy. The same trend was observed when irradiation was performed for grapes fortified with malathion (8 ppm) and cypermethrin (2 ppm) for absorbed doses up to 2 kGy. Ionizing radiation reduced the residues of pirimiphos-methyl (0.05 ppm in potatoes at1 kGy, 1 ppm in grapes at 2 kGy and 0.1 ppm in dates at1 kGy), malathion (8 ppm in grapes at 7 kGy) and cypermethrin (2 ppm in grapes at 7 kGy) to below maximum residue limits (MRLs).     

Bioremediation of Single and Mixture of Pesticide-Contaminated Soils by Mixed Pesticide-Enriched Cultures

In the present study, degradation efficiencies for individual as well as mixed pesticide in different Indian soils, by mixed pesticide-enriched cultures, were evaluated under submerged and unsaturated conditions, Lindane (L), methyl parathion (MP), carbofuran (C), and a mixture of L, MP, and C were used in the study. For all the various conditions considered, methyl parathion degradation was the maximum and lindane degradation was the minimum. The degradation kinetics of the pesticides in sandy, clayey, compost, and red soils by various microbial isolates were studied. It was observed that adsorption was maximum and degradation of pesticides was minimum in compost soil. The degradation efficiencies of pesticides in liquid phase associated with soil sediment were less than those under the normal liquid phase conditions as leaching of pesticides from soil phase was continuous. Pesticide degradation was more in submerged soils compared to that in unsaturated soils. The degradation by-products of individual and mixed pesticides in liquid, unsaturated, and submerged soils were identified. Different metabolites were produced under submerged and unsaturated conditions.     

Investigation of norflurazon pesticide photodegradation using plasma desorption time-of-flight mass spectrometry analysis

We have previously demonstrated that PD-TOFMS (plasma desorption time-of-flight mass spectrometry) analysis is a powerful technique for the in situ analysis of pesticides deposited or adsorbed on solid materials. With the aim of producing reproducible data on the modification of a pesticide under controlled photodegradation conditions, we have now undertaken a study where both the substrate and the pesticide are well characterized. This is the case for norflurazon deposited onto an aluminium substrate, in particular regarding the reproducibility of preparation of the samples and the change with time of their chemical composition. Degradation parameters have been derived from the variation in yield of ions representative of the molecule and of its breakdown products and, particularly, from the time required for 50% dissipation of their initial concentration (DT50). DT50 values ranging between 1 and 10 h have been found. An interpretation of the degradation process is proposed from the decay of other ions. As expected, the degradation is faster when the UV sunlight is unfiltered (a factor of 3.8 for the molecule, and around 5 for the breakdown products).     

Gas‐phase copper and silver complexes with phosphorothioate and phosphorodithioate pesticides investigated using electrospray ionization mass spectrometry

Efforts to improve agricultural productivity have led to a growing dependency on organophosphorus pesticides. Phosphorothioate and phosphorodithioate pesticides are organophosphorus pesticide subclasses with widespread application for the control of insects feeding on vegetables and fruits. However, even low doses of these pesticides can cause neurological problems in humans; thus, their determination and monitoring in agricultural foodstuffs is important for human health. Phosphorothioate and phosphorodithioate pesticides may be poorly ionized during electrospray, adversely affecting limits of detection. These pesticides can form complexes with Cu²⁺ and Ag⁺, however, potentially improving ionization. In the present work, we used electrospray ionization/mass spectrometry (ESI/MS) to study fenitrothion, parathion, diazinon, and malathion coordination complexes with silver and copper ions. Stable 1 : 1 and 1 : 2 metal/pesticide complexes were detected. Mass spectra acquired from pesticide solutions containing Ag⁺ or Cu²⁺ showed a significant increase in signal‐to‐background ratio over those acquired from solutions containing only the pesticides, with Ag⁺ improving detection more effectively than Cu²⁺. Addition of Ag⁺ to a pesticide solution improved the limit of detection by ten times. The relative affinity of each pesticide for Ag⁺ was related to complex stability, following the order diazinon > malathion > fenitrothion > parathion. The formation of Ag⁺–pesticide complexes can significantly improve the detection of phosphorothioate and phosphorodithioate pesticides using ESI/MS. The technique could potentially be used in reactive desorption electrospray ionization/mass spectrometry to detect phosphorothioate and phosphorodithioate pesticides on fruit and vegetable skins. Copyright © 2015 John Wiley & Sons, Ltd.     

Identification of the nitrogen-based blister agents bis(2-chloroethyl)methylamine (HN-2) and tris(2-chloroethyl)amine (HN-3) and their hydrolysis products on soil using ion trap secondary ion mass spectrometry

The nitrogen blister agents HN-2 (bis(2-chloroethyl)methylamine) and HN-3 (tris(2-chloroethyl)amine) were directly analyzed on the surface of soil samples using ion trap secondary ion mass spectrometry (SIMS). In the presence of water, HN-1 (bis(2-choroethyl)ethylamine), HN-2 and HN-3 undergo hydrolysis to form N-ethyldiethanolamine, N-methyldiethanolamine and triethanolamine (TEA), respectively; these compounds can be readily detected as adsorbed species on soil particles. When soil samples spiked with HN-3 in alcohol were analyzed, 2-alkoxyethylamine derivatives were observed on the sample surfaces. This result shows that nitrogen blister agents will undergo condensation reactions with nucleophilic compounds and emphasizes the need for an analytical methodology capable of detecting a range of degradation and condensation products on environmental surfaces. The ability of ion trap SIMS to isolate and accumulate ions, and then perform tandem mass spectrometric analysis improves the detection of low-abundance surface contaminants and the selectivity of the technique. Utilizing these techniques, the limits of detection for HN-3 were studied as a function of surface coverage. It was found that HN-3 could be detected at a surface coverage of 0.01 monolayer, which corresponds to 20 ppm (mass/mass) for a soil having a surface area of 2.2 m(2) g(-1). TEA, the exhaustive hydrolysis product of HN-3, was detected at a surface coverage of 0.001 monolayer, which corresponds to 0.86 ppm.     

Study of the behaviour of azinphos-methyl in a clay mineral by batch and column leaching

Research efforts dealing with the processes affecting the transport of pesticides in soils are needed in order to prevent further damage of surface and groundwater reserves. Although organic matter has been recognised as the most important contributor to the adsorption of non-ionic organic pesticides in soils, in some cases clay minerals may have an important role in the retention of these compounds. The present study was designed to improve the knowledge of the behaviour of azinphos-methyl in soils. Coefficients from adsorption isotherms and HPLC analysis of soil column leachates were used in this work for predicting pesticide mobility in soils. The studied clay mineral was a Spanish bentonite with a predominant montmorillonite fraction. The results showed that azinphos-methyl was adsorbed on the clay mineral and demonstrated the catalytic effect of bentonite on the hydrolysis of the pesticide.     

Development of a procedure for the multiresidue analysis of pesticides in vineyard soils and its application to real samples

A procedure for multiresidue analysis was developed for the extraction and determination of 17 pesticides, including herbicides, fungicides, and insecticides, as well as certain degradation products, in vineyard soils from La Rioja region (Spain). Different solvents and mixtures were tested in spiked pesticide‐free soils, and pesticides were comparatively evaluated by gas chromatography with mass spectrometry and liquid chromatography with mass spectrometry. Recoveries >70%, with relative standard deviations <9%, were obtained when a mixture of methanol/acetone or a mixture of methanol/CaCl₂ 0.01 M for the most polar compounds was selected as the extraction solvent. Method validation was accomplished with acceptable linearity (r² ≥ 0.987) within the concentration range of 0.005–1 μg/mL corresponding to 1.667–333.4 μg/kg and 0.835–167.1 μg/kg for liquid chromatography with mass spectrometry and gas chromatography with mass spectrometry, respectively, and detection limits <0.4 μg/kg for the compounds were studied. The extraction method was applied to 17 real vineyard soil samples, and terbuthylazine and its metabolite desethylterbuthylazine were the most ubiquitous compounds, as they were detected in the 100% of the soils analyzed. The presence of fungicides was also high, and the presence of insecticides was lower than other pesticides. The results confirm the usefulness of the optimized procedure for monitoring residues in vineyard soils.     

Use of SPME extraction to determine organophosphorus pesticides adsorption phenomena in water and soil matrices

Solid-phase micro extraction (SPME) coupled with GC enables rapid and simple analysis of organophosphorus pesticides in a range of complex matrices. Investigations were made into the extraction efficiencies from water of six organophosphorus insecticides (methamidophos, omethoate, dimethoate, parathion methyl, malathion, and parathion ethyl) showing a wide range of polarities. Three SPME fibres coated with different stationary phases, polydimethylsiloxane, polyacrylate, and carbowax-divinylbenzene (CW-DVB), were investigated. Water was spiked with the pesticides at concentrations from 1 to 0.01 µg mL-1, and the solutions used for optimization of the procedure. The CW-DVB fibre, with a 65 µm coating, gave the best performance. The optimized experimental conditions were sample volume 10 mL at 20°C, equilibration time 16 min, pH 5, and presence of 10% w/v NaCl. SPME analyses were performed on solutions obtained by equilibrating aqueous pesticide solutions with six certified soils with various physico-chemical characteristics. SPME data were also assessed by comparison with analyses performed by using conventional solid-phase extraction. Results indicate the suitability of SPME for analysis of pesticides in environmental water samples.     

Multiresidue determination of pesticides in acid-clay soils from Thailand

Tropical and temperate soils differ with respect to their chemical conditions and mineral composition. Consequently, assessment of the contamination of tropical soils with pesticides requires methods that provide exhaustive extraction from the specific soil matrix and reliable quantification. Our objective was to optimize the simultaneous extraction and determination of 32 representative pesticides (organophosphates, organochlorines, synthetic pyrethroids, triazines, acetamides, carbamates, diphenyl ethers, acylalanines, oxadiazoles, thiadiazoles, and phenoxy compounds) frequently used in Thailand. The compounds were added to a clayey Ultisol-topsoil (45% clay) from the Yom Region in Northern Thailand. Ten different solvent mixtures were tested; the use of a shake extraction with acetone-ethyl acetate-water (3 + 1 + 1, v/v/v) was most effective in providing exhaustive and reproducible extraction of pesticides both from freshly fortified soil and from fortified soil after incubation for 14-28 days. The pesticides were separated and quantified by using gas chromatography with mass selective detection. Except for methamidophos, which was almost completely lost during sample workup, the recoveries of all pesticides from soil ranged from 68.6 to 104% (mean standard error, 2.8%) for freshly spiked samples and from 45.9 to 107% (mean standard error, 2.3%) for spiked samples incubated for 14 days. The use of internal standards compensated for the losses of most pesticides during workup and increased the mean recovery of the pesticides from freshly fortified soil to 96%. The method was successfully applied to the determination of environmental concentrations of pesticides in a range of Thai agricultural soils.     

Evaluation of multi-walled carbon nanotubes as solid-phase extraction adsorbents of pesticides from agricultural, ornamental and forestal soils

A new, simple and cost-effective method based on the use of multi-walled carbon nanotubes (MWCNTs) as solid-phase extraction stationary phases is proposed for the determination of a group of seven organophosphorus pesticides (i.e. ethoprophos, diazinon, chlorpyriphos-methyl, fenitrothion, malathion, chlorpyriphos and phosmet) and one thiadiazine (buprofezin) in different kinds of soil samples (forestal, ornamental and agricultural) using gas chromatography with nitrogen phosphorus detection. Soils were first ultrasound extracted with 10 mL 1:1 methanol/acetonitrile (v/v) and the evaporated extract redissolved in 20 mL water (pH 6.0) was passed through 100 mg of MWCNTs of 10-15 nm o.d., 2-6 nm i.d. and 0.1-10 μm length. Elution was carried out with 20 mL dichloromethane. The method was validated in terms of linearity, precision, recovery, accuracy and selectivity. Matrix-matched calibration was carried out for each type of soil since statistical differences between the calibration curves constructed in pure solvent and in the reconstituted soil extract were found for most of the pesticides under study. Recovery values of spiked samples ranged between 54 and 91% for the three types of soils (limits of detection (LODs) between 2.97 and 9.49 ng g⁻¹), except for chlorpyrifos, chlorpyrifos-methyl and buprofezin which ranged between 12 and 54% (LODs between 3.14 and 72.4 ng g⁻¹), which are the pesticides with the highest soil organic carbon sorption coefficient (K_OC) values. Using a one-sample test (Student's t-test) with fortified samples at two concentration levels in each type of soil, no significant differences were observed between the real and the experimental values (accuracy percentages ranged between 87 and 117%). It is the first time that the adsorptive potential of MWCNTs for the extraction of organophosphorus pesticides from soils is investigated.     

Soil Type and Herbicides Adsorption

Abstract

Herbicides behaviour in soils greatly depends on adsorption through its influence on degradation and movement. The adsorption intensity depends on both the chemical structure of pesticides, the nature of soil constituents and soil physico-chemical factors such as the pH. In this paper, the role played by these factors is analysed and used to evaluate the possible use of soil surveys for assessing adsorption behaviour of pesticides in soils. The analysis is based on adsorption measurements of three herbicides (atrazine, terbutryn and 2,4-D) by several soils differing in their mineralogical composition, organic matter content and pH. Using statistical analysis, it is shown that some relations can be defined between soil types and adsorption behaviour. These relations are strongly dependent on the electrical state of the herbicide molecule (cationic, anionic and neutral).     

Determination of pesticides in soil samples by supercritical fluid chromatography-atmospheric pressure chemical ionisation mass spectrometric detection

This paper presents an analytical technique for the determination of pesticides in soil by packed-column supercritical fluid chromatography interfaced with atmospheric pressure chemical ionisation mass spectrometry (pSFC-APCI-MS). The technique provides a versatile method for the detection and quantification of pesticides belonging to three different commonly used classes, triazines (ametryne, atrazine), carbamates (carbofuran) and sulfonylureas (chlorsulfuron, metsulfuron methyl and benzsulfuron methyl). The APCI mass spectra for all the pesticides studied consisted of protonated molecule ions as the most abundant ion at low cone voltages, except for metsulfuron methyl and benzsulfuron methyl, which gave a fragment ion as the most abundant ion with the protonated molecule ion at low intensity. Increasing the cone voltage provided informative fragmentation patterns for all species. The technique shows good linearity over the concentration range of 0.1-50 micrograms ml-1, with r2 values as follows: atrazine 0.997, ametryne 0.995, carbofuran 0.999, benzsulfuron methyl 0.999, chlorsulfuron 0.995 and metsulfuron methyl 0.997. The detection limits in the selected ion mode were atrazine 201, ametryne 144 and carbofuran 385 pg, which were calculated by using the standard solution, and benzsulfuron methyl 2.045, chlorsulfuron 1.435 and metsulfuron methyl 2.414 ng, which were determined by using spiked soil samples. The pSFC-MS system was shown to have a high degree of reproducibility. The technique was then applied to the determination of the above pesticides in soil samples. The results obtained show that there is no matrix effect from the soil and that the detection limits for all pesticides in soil were similar to those found for the standard solutions.     

Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry

A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid‐phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C₁₈ cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected‐ion monitoring mode. Good linear relationships were obtained in the range of 0.1–50 μg/L for chlorpyrifos, and 0.05–50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54–86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.     

Optimization of separation and detection conditions for the multiresidue analysis of pesticides in grapes by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

A comprehensive GCxGC-TOFMS method was optimized for multiresidue analysis of pesticides using a combination of a non-polar (RTX-5MS, 10 m x 0.18 mm x 0.2 microm) and a polar capillary column (TR-50MS, 1 m x 0.1 mm x 0.1 microm), connected in series through a dual stage thermal modulator. The method resolved the co-elution problems as observed in full scan one-dimensional GC-MS analysis and allowed chromatographic separation of 51 pesticides within 24 min run time with library-searchable mass spectrometric confirmation. Four pesticides, viz. chlorpyrifos-methyl, vinclozoline, parathion-methyl and heptachlor could be baseline separated on GCxGC, which were otherwise closely eluting and interfering each other's detection in 1D GC-MS run. Similarly, it could be possible to separate myclobutanil, buprofezin, flusilazole and oxyfluorfen on GCxGC. Although in 1D GC-MS, these closely eluting compounds could be identified through deconvolution algorithm and 'peak-find' option of the Chromatof software but the spectral purity significantly improved on GCxGC analysis. Thorough optimization was accomplished for the oven temperature programming, ion source temperature and GCxGC parameters like modulation period, duration of hot pulses, modulation-offset temperature, acquisition rate, etc. to achieve best possible separation of the test compounds. The limit of detection significantly improved by 2-12 times on GCxGC-TOFMS against GC-TOFMS because of sharper and narrower peak shapes. The method was tested for grape matrix after preparing the samples using previously described method and recoveries of the entire test pesticides were within 70-110% at 10 ng/g level of fortification. GCxGC-TOFMS was found to be an excellent technique for library-based screening of pesticides with high accuracy and sensitivity.     

Multi-residue method for the analysis of 101 pesticides and their degradates in food and water samples by liquid chromatography/time-of-flight mass spectrometry

A comprehensive multi-residue method for the chromatographic separation and accurate mass identification of 101 pesticides and their degradation products using liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) is reported here. Several classes of compounds belonging to different chemical families (triazines, organophosphorous, carbamates, phenylureas, neonicotinoids, etc.) were carefully chosen to cover a wide range of applications in the environmental field. Excellent chromatographic separation was achieved by the use of narrow accurate mass windows (0.05 Da) in a 30 min interval. Accurate mass measurements were always below 2 ppm error for all the pesticides studied. A table compiling the accurate masses for 101 compounds together with the accurate mass of several fragment ions is included. At least the accurate mass for one main fragment ion for each pesticide was obtained to achieve the minimum of identification points according to the 2002/657/EC European Decision, thus fulfilling the EU point system requirement for identification of contaminants in samples. The method was validated with vegetable samples. Calibration curves were linear and covered two orders of magnitude (from 5 to 500 microg/L) for most of the compounds studied. Instrument detection limits (LODs) ranged from 0.04 to 150 microg/kg in green-pepper samples. The methodology was successfully applied to the analysis of vegetable and water samples containing pesticides and their degradation products. This paper serves as a guide for those working in the analytical field of pesticides, as well as a powerful tool for finding non-targets and unknowns in environmental samples that have not been previously included in any of the routine target multi-residue methods.     

Analysis of Malathion pesticide residues in rice samples using ultrasound-assisted emulsification-microextraction coupled to UV photoionization source ion mobility spectrometry

The present paper describes the validation of ultrasound-assisted emulsification-microextraction method followed by ion mobility spectrometry (IMS) for determination malathion pesticides. Ultrasound radiation was applied for accelerating the emulsification of microliter organic solvent in aqueous solutions and enhancing the microextraction efficiency. This preconcentration step combined with IMS detection provided a precise and accurate method for determination of trace amounts of malathion pesticides. The effect of parameters influencing the extraction efficiency such as sonication time, type of extraction solvent, extraction solvent volume, and salt concentration were investigated and discussed. Under the optimum conditions, enrichment factors was 270 with corresponding LOD of 4 μg/L. Linearity with a coefficient of estimation (r²) were >0.99 in the concentration level range of 6–750 μg/L for extraction of Malathion in water samples. The applicability of the proposed method was evaluated by determination of the residues of the investigated pesticide in rice paddy water gathered from four stations during 60 days after spraying (June 2014), and in storage rice samples in Mazandaran province, Iran.     

Pollution Potential of Some Triazole Pesticides

Abstract

The widespread occurrence of pesticides, especially in the groundwater has stimulated research into the behavior of these agrochemicals in the environment. In this work a simple model to describe the fate of the two triazole fungicides Flutriafol and Flusilazol in a silt soil is presented. For this purpose we constructed mini-columns of soil, on which we applied the two fungicides, the percolation waters and the soils were collected at different times and the pesticides quantified in these samples. In the first part, these experiments were carried out outdoors during a period of 6 months on the silt soil and in a second part, we did similar indoor experiments with the same soil and with two others. To complete our work, we studied the adsorption of these two compounds on these three types of soil with batch equilibrium experiments. The results demonstrate that the fungicide Flusilazol is an immobile compound in soil, being strongly adsorbed whatever the nature of the soil. The Flutriafol is slightly to moderately mobile in the different soils, being less adsorbed.