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E Papadopoulou-Mourkidou

Publications and source records attributed to E Papadopoulou-Mourkidou.

16 recordsLinked to original sources
PubMed2004

The potential of pesticides to contaminate the groundwater resources of the Axios river basin in Macedonia, Northern Greece. Part I. Monitoring study in the north part of the basin.

The Axios river basin is an area of high agricultural importance for Macedonia, Northern Greece. High priced crops such as cotton, corn, sugarbeets, vegetables and rice are rotated with cereals and alfalfa and thus a great variety of pesticides are used annually for the control of pests and diseases. Moreover, the groundwater resources of the specific area constitute the main source of potable water for the surrounding cities and villages. Therefore, a study was initiated to investigate the probable risks of groundwater contamination with pesticides. The leaching of pesticides from agricultural soils was monitored in the phreatic horizon as well as in soil water samples collected with suction lysimeters. In parallel studies, the presence of pesticides in the irrigation water and the water of Axios river was also monitored. Pesticides like carbofuran, atrazine, alachlor and prometryne, which were regularly applied in the northern part of the basin during 1992-1994 were detected at concentrations occasionally exceeding 1 microg/l in soil water from the deeper soil layers and in the phreatic horizon. Residues of pesticides others than the ones applied in the studied area like propanil, terbufos and paraoxon-methyl were also detected at the deeper soil layers and in the phreatic horizon. The latter pesticides were also detected at significant concentrations in the irrigation water which mainly consisted of riverine water. The lack of an independent soil draining system and the use of riverine water for irrigation purposes resulted in the redistribution of residual amounts of these pesticides in the phreatic horizon beneath the agricultural area.

Agriculture↗
PubMed2004

The potential of pesticides to contaminate the groundwater resources of the Axios river basin. Part II. Monitoring study in the south part of the basin.

A monitoring study was conducted during 1992-1994 in the south part of the Axios river basin, which constitutes one of the main rice-cultivated basins of Greece. The potential of pesticides to contaminate groundwater resources was assessed under realistic agricultural conditions using suction lysimeters. Pesticide residues were also measured in local drainage canals, the phreatic horizon and Axios river. Carbofuran, atrazine, alachlor, prometryne and propanil were regularly detected at concentrations exceeding 1 microg/l in the soil water of deeper soil layers and in the phreatic horizon of the fields. Residues of those pesticides were measured in the soil water and the phreatic horizon of all the studied fields even though they had only been applied in certain fields. This almost uniform distribution of pesticide residues across the whole of the studied area was attributed to rice cultivation. Soil water and its pesticidal content was horizontally transported from saturated soil conditions beneath rice paddies to adjacent corn or cotton-cultivated fields with lower soil moisture contents. The presence of high pesticide concentrations in the water of the Axios river, which was used for the irrigation of the studied area, had probably contributed to the generalized pesticide contamination of the soil water in the studied area. These results suggest that there is a high risk for groundwater contamination in the basin.

Agriculture↗
PubMed2002

Analysis of phenoxyalkanoic acid herbicides and their phenolic conversion products in soil by microwave assisted solvent extraction and subsequent analysis of extracts by on-line solid-phase extraction-liquid chromatography.

A multiresidue method for the determination of phenoxyalkanoic acid herbicides and their phenolic conversion products in soil was developed. The method was based on microwave-assisted solvent extraction (MASE) of soil samples by an aqueous methanolic mixture and subsequent analysis of extracts by automated solid-phase extraction followed by on-line high-performance liquid chromatography and diode array detection. MASE parameters (extraction temperature and time, composition of the extraction mixture and extraction volume) were optimized with respect to analyte recoveries. The method was validated with two types of soils containing 1.5 and 3.5% organic matter, respectively, both types containing fresh and aged residues of sought analytes. Under the selected analytical conditions when soils with fresh residues were analyzed all target analytes were recovered above 80% from the soil containing 1.5% organic matter, while limits of identification at the level of 20-40 ng/g were achieved. From the soil containing 3.5% organic matter the least polar phenolic analytes exhibited slightly reduced recoveries, while identification limits of 30-50 ng/g were achieved. Samples with aged residues exhibited reduced recoveries for some analytes, the reduction amounting up to 6-12% within 1 month of aging period depending on soil organic matter.

Chromatography, High Pressure Liquid↗
PubMed2001

Automated trace level determination of glyphosate and aminomethyl phosphonic acid in water by on-line anion-exchange solid-phase extraction followed by cation-exchange liquid chromatography and post-column derivatization.

An automated method based on the on-line coupling of anion-exchange solid-phase extraction (SPE) and cation-exchange liquid chromatography followed by post-column derivatization and fluorescence detection has been developed for the trace level determination of glyphosate and its primary conversion product aminomethyl phosphonic acid (AMPA) in water. PRP-X100 poly(styrene-divinylbenzene)-trimethylammonium anion-exchange cartridges (20 x 2 mm, 10 microm) were selected for the SPE of glyphosate and AMPA. The ionic compounds present in the samples strongly influenced the extraction of both analytes; however, when an on-line ion-exchange clean-up step was introduced before sample SPE, the problem was largely solved. By processing 100-ml samples detection limits better than 0.02 microg/l for glyphosate and 0.1 microg/l for AMPA were achieved in river water. Both analytes were unstable in solution and the approach of storing samples on the PRP-X100 SPE cartridges was evaluated for a period of 1 month under three different storage conditions (deep freeze, refrigeration and 20 degrees C).

Cation Exchange Resins↗
PubMed2001

Glutathione S-transferase in the defence against pyrethroids in insects.

The correlation between the natural levels of GST and the tolerance to the insecticide decamethrin (dMT), as well as the interaction between the molecules of affinity purified enzyme and the insecticide were investigated in order to collect further information on the obscure role of the Glutathione S-transferase system (GST) as a mechanism of defence against pyrethroids. The studies were carried out, comparatively, on the larvae and pupae developmental stages of the coleopteran Tenebrio molitor, which exhibit varying natural levels of GST activity. No stage dependent susceptibility of the insect against pyrethroid insecticides was found during the first 24 h, however 48 h after treatment, the KD50 dose increased significantly due to the recovery of some individuals from the larvae stage. Simultaneous injection of decamethrin with compounds which inhibit GST activity in vitro, resulted in an increased tolerance, which was more pronounced in the pupae stage. Inhibition studies combined with competitive fluorescence spectroscopy and high pressure liquid chromatography (HPLC) showed that the insecticide binds probably to the active site of the enzyme inhibiting its activity towards CDNB in a competitive manner, but is not conjugated with GSH. According to this, GST offers a passive protection towards pyrethroid insecticides by binding to their molecule in a sequestering mechanism.

Anilino Naphthalenesulfonates↗
PubMed2001

Occurrence and spatial and temporal distribution of pesticide residues in groundwater of major corn-growing areas of Greece (1996-1997).

During 1996-1997, residues of selected pesticides were monitored, at 3-month intervals, in 80 wells, including both irrigation and drinking water wells, distributed among the main corn-growing areas (Pieria, Thessaloniki, Serres, Kavala, and Evros) of Greece. Pesticide residues were found in 48% of the wells; however, in most cases residues were very low ranging from LOQs (quantification limits of the analytical methods) to <0.1 microg/L, while in 11% (nine wells) pesticide residues higher than 0.1 microg/L were present. Most of the latter wells were found in Evros and specificallythe Ardas Valley. The frequency of occurrence, in descending order, was atrazine > DEA > alachlor = metolachlor; however, the order of descending concentrations was atrazine > metolachlor > DEA > alachlor. The occurrence and the spatial and temporal distribution patterns of pesticide residues indicate that at the present the situation of groundwater quality is favorable throughout the corn-growing areas of Greece with the exception of the Ardas Valley.

Acetamides↗
PubMed2001

The role of glutathione S-transferases in the detoxification of some organophosphorus insecticides in larvae and pupae of the yellow mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae).

The correlation between the natural levels of glutathione S-transferase (GST) and the tolerance to the organophosphorus insecticides parathion-methyl and paraoxon-methyl, as well as the interaction of affinity-purified enzyme and the insecticides were investigated in order to collect further information on the role of the glutathione S-transferase system as a mechanism of defence against insecticides in insects. The studies were carried out on the larvae and pupae of the coleopteran Tenebrio molitor L, which exhibit varying natural levels of GST activity. Stage-dependent susceptibility of the insect against insecticides was observed during the first 24 h. However, 48 h after treatment, the KD50 value increased significantly due to the recovery of some individuals. Simultaneous injection of insecticide with compounds which inhibit GST activity in vitro caused an alteration in susceptibility of insects 24 or 48 h post-treatment, depending on stage and insecticide used. Inhibition studies combined with competitive fluorescence spectroscopy revealed that the insecticides probably bind to the active site of the enzyme, thus inhibiting its activity towards 1-chloro-2,4-dinitrobenzene in a competitive manner. High-performance liquid chromatography and gas chromatography revealed that T molitor GST catalyses the conjugation of the insecticides studied to a reduced form of glutathione (GSH). From the above experimental results, it is considered that GST offers a protection against the organophosphorus insecticides studied by active site binding and subsequent conjugation with GSH.

Animals↗
PubMed2001

Use of an automated on-line SPE-HPLC method to monitor caffeine and selected aniline and phenol compounds in aquatic systems of Macedonia-Thrace, Greece.

Caffeine and selected aniline and phenol compounds have been monitored in the river, lake, and ground water of Northern Greece (Macedonia-Thrace) from September 1999 to December 2000 by means of a fully automated on-line SPE-HPLC method. Among the target aniline and phenol compounds the most abundant was 2,6-di-tert-butyl-4-methylphenol, which was found to be present in both surface and ground water samples. Caffeine was also very frequently present in river and ground water, although its presence in lake water was rare. Caffeine and 2,6-di-tert-butyl-4-methylphenol were also monitored by off-line SPE of water samples and GC-ion-trap MS analysis of extracts.

Aniline Compounds↗
PubMed2000

Development of an automated on-line solid-phase extraction-high-performance liquid chromatographic method for the analysis of aniline, phenol, caffeine and various selected substituted aniline and phenol compounds in aqueous matrices.

A fully automated solid-phase extraction (SPE)-high-performance liquid chromatographic method has been developed for the simultaneous analysis of substituted anilines and phenols in aqueous matrices at the low- to sub-microg/l level. Diode array and electrochemical detection operated in tandem mode were used for analyte detection. Two new polymeric sorbent materials (Hysphere-GP and Hysphere-SH) were evaluated for the on-line SPE of substituted anilines and phenols from aqueous matrices and their performance was compared with the PRP-1 and PLRP-S sorbents. Hysphere-GP sorbent packed in 10 x 2 mm cartridges was found to give better results in terms of sensitivity and selectivity of the overall analytical method. The proposed analytical method was validated for the analysis of these compounds in Axios river water that receives industrial, communal and agricultural wastes. The detection limits for all the compounds range between 0.05 and 0.2 microg/l, except for aniline and phenol which have detection limits of 0.5 and 1 microg/l, respectively (aniline detected by electrochemical detection). The recoveries for all the compounds are higher than 75% except for aniline (6%), phenol (50%) and 3-chlorophenol (67%). Finally, in order to evaluate the efficiency of the Hysphere-GP (10 x 2 mm) cartridges for sample stabilization and storage, the stability of the compounds of interest at the sorbed state onto these cartridges has been evaluated under three different temperature regimes (deep freeze, refrigeration, 20 degrees C).

Aniline Compounds↗
PubMed1997

Neurotoxic action of six pyrethroid insecticides on the isolated sciatic nerve of a frog (Rana ridibunda).

The neurotoxic action of six pyrethroid insecticides, four type II, (flucythrinate, deltamethrin, fenvalerate, fluvalinate) and two type I (cis- and trans-permethrin) was compared on the isolated sciatic nerve of frog. The nerve was exposed to pyrethroids for 30 min and action potentials were recorded for more than 45 hr after exposure. From the plots of the amplitude of the compound action potential vs time, it was possible to estimate, for each compound, the minimum effective concentration, the concentration which is required to reduce the amplitude of the compound action potential to 50% of its control value (mEC50). Flucythrinate was the most toxic compound, while toxicity decreased in the value: deltamethrin > fenvalerate > fluvalinate >> cis-permethrin > trans-permethrin. Low neurotoxicity of cis-permethrin and trans-permethrin (type I pyrethroids) was expected. The neurotoxicity of type I pyrethroids is mainly due to an action at the synapse, which are not present in the frog sciatic nerve preparation. The relative potencies of the four type II compounds agree with their acute toxicity estimated using the LD50.

Acetone↗
PubMed1989

Temperature-dependent solute retention time variations, base-line drifts, and solute peak splits during the analysis of fenvalerate by a high-performance liquid chromatography/diode array system.

The optical isomers of fenvalerate, (RS)-alpha-cyano(3-phenoxyphenyl)methyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate, were analyzed by high-performance liquid chromatography (HPLC) on chiral columns eluted with mixtures of 2-propanol in hexane. The HPLC eluates were monitored by a photodiode-array ultraviolet absorbance detector. When the HPLC columns were maintained at ambient temperature, chromatograms with drifting base lines of four to eight peaks, instead of four, and isograms, three-dimensional chromatograms, with "negative" peak artifacts coeluted with fenvalerate isomers were usually obtained during a continuous run of the HPLC system for many days and by injecting onto the system only fenvalerate analytical standard solutions. Chromatograms and isograms without artifacts and straight base lines were obtained only when the HPLC column was thermostated and well equilibrated for at least 8-10 h.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

A fully automated system for analysis of pesticides in water: on-line extraction followed by liquid chromatography-tandem photodiode array/postcolumn derivatization/fluorescence detection.

A fully automated system for on-line solid phase extraction (SPE) followed by high-performance liquid chromatography (HPLC) with tandem detection with a photodiode array detector and a fluorescence detector (after postcolumn derivatization) was developed for analysis of many chemical classes of pesticides and their major conversion products in aquatic systems. An automated on-line-SPE system (Prospekt) operated with reversed-phase cartridges (PRP-1) extracts analytes from 100 mL acidified (pH = 3) filtered water sample. On-line HPLC analysis is performed with a 15 cm C18 analytical column eluted with a mobile phase of phosphate (pH = 3)-acetonitrile in 25 min linear gradient mode. Solutes are detected by tandem diode array/derivatization/fluorescence detection. The system is controlled and monitored by a single computer operated with Millenium software. Recoveries of most analytes in samples fortified at 1 microgram/L are > 90%, with relative standard deviation values of < 5%. For a few very polar analytes, mostly N-methylcarbamoyloximes (i.e., aldicarb sulfone, methomyl, and oxamyl), recoveries are < 20%. However, for these compounds, as well as for the rest of the N-methylcarbamates except for aldicarb sulfoxide and butoxycarboxim, the limits of detection (LODs) are 0.005-0.05 microgram/L. LODs for aldicarb sulfoxide and butoxycarboxim are 0.2 and 0.1 microgram, respectively. LODs for the rest of the analytes except 4-nitrophenol, bentazone, captan, decamethrin, and MCPA are 0.05-0.1 microgram/L. LODs for the latter compounds are 0.2-1.0 microgram/L. The system can be operated unattended.

Autoanalysis↗
PubMedDate not supplied

Postharvest-applied agrochemicals and their residues in fresh fruits and vegetables.

Many agrochemicals are applied postharvest on fruits and vegetables to extend their lives and preserve quality during storage, transport, and marketing. Persistence and distribution of residues on the edible portions of produce have been reported for citrus fruits, pome fruits, stone fruits, mangos, strawberries, bananas, kiwi fruits, avocados, some minor fruit commodities, and bell peppers and tomatoes. Data on the persistance and residues of the fungicides benomyl, biphenyl, sec-butylamine, captan, carbendazim, dicloran, fosetyl-aluminum, guazatine, imazalli, iprodione, metalaxyl, o-phenylphenol, prochloraz, thiabendazole, thiophanate-methyl, triadimeton, and vinclozolin, the fumigants ethylene dibromide, methyl bromide, and sulfur dioxide, the insecticides dimethoate and fenthion, the antiscald compounds diphenylamine and ethoxyquin, and the growth regulators 2,4-D and daminozide are presented and discussed.

Agrochemicals↗