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Cytogenetic effects on human lymphocytes of a mixture of fifteen pesticides commonly used in Italy.

Lymphocytes obtained from 5 healthy donors were incubated with a mixture of 15 pesticides commonly found in foods of central Italy (dithiocarbamates (20.7%), benomyl (19.6%), thiabendazole (14.9%), diphenylamine (14.4%), chlorthalonil (13.1%), procymidone (8.0%), methidathion (2.3%), chlorpyrifos-ethyl (2%), fenarimol (1.9%), parathion-methyl (1%), chlorpropham, parathion, vinchlozolin, chlorfenvinphos and pirimiphos-ethyl (< 1%)). The percent of each pesticide in the mixture was proportional to its average concentration in foods. Incubated with the lymphocytes at a concentration of 1-20 micrograms/ml the pesticide mixture did not induce significant variations in the number of hypodiploid, hyperdiploid and polyploid cells or in the number of chromosome and chromatid aberrations. On the contrary, we observed a dose-dependent increase in the number of nonsynchronous centromeric separations which reached the level of 37.9% at 20 micrograms/ml of pesticide mixture in the incubation medium. This effect was not observed when benomyl was excluded from the mixture. These data show that the removal of benomyl could decrease the toxicity of pesticide residues present in human food.

Adult↗

Automated determination of phenylcarbamate herbicides in environmental waters by on-line trace enrichment and reversed-phase liquid chromatography-diode array detection.

A fully automated liquid chromatographic method using on-line trace-enrichment, gradient elution and diode array detection is described for the trace-level determination of several phenylcarbamate herbicides, such as carbetamide, propham, desmedipham, phenmedipham, chlorbufam and chlorpropham, in environmental water samples. In this work, two different enrichment pre-columns have been assayed, a 5.8 x 4.6 mm I.D., 10 microns ODS Prelute cartridge and a 10 x 2 mm I.D. cartridge filled with 10 microns PRP-1 polymer, both coupled to a 150 x 4.6 mm I.D. analytical column filled with 5 microns ODS. Using the C18 pre-column, up to 50 ml of water sample could be percolated without peak broadening of any compound. However, a lack of reproducibility was observed in the case of carbetamide, the most polar analyte, after performing recovery experiments by percolating drinking and surface water samples spiked at several levels (0.5 and 4 micrograms l-1). On the other hand, the PRP-1 pre-column allowed the enrichment up to 100 ml of water sample with satisfactory results for every compound, including carbetamide. The procedure was validated by recovery experiments in environmental water samples spiked at 0.2 and 1 microgram l-1 yielding average recoveries between 84-108% with relative standard deviations in the range 2-12%. Detection limits as low as 0.04 microgram l-1 were achieved. It was observed that desmedipham and phenmedipham degraded rapidly in the environmental water samples as showed the degradation studies performed along 24 h in drinking and surface waters spiked at 4 micrograms l-1. Although the standard mixture, prepared in HPLC water, was stable for around one week, in the environmental water matrices more than 95% of each herbicide degraded after 6 h, and new chromatographic peaks corresponding to the degradation products were detected.

Autoanalysis↗

Binding capacity of various fibre to pesticide residues under simulated gastrointestinal conditions.

The purpose of this study was to compare the effect of the nature and quantity of various dietary fibre (cellulose, hemicellulose, pectin, lignin) in diets on the binding capacity to pesticides azinphos-methyl (AZM), chlorpropham (CLP), chlorothalonil (CKL), permethrin (PER) as estimated by solubility under conditions of pH and temperature simulating those in the gastrointestinal tract (incubated at pH 2 for 30 min at 37 degrees C, then at pH 7 for 60 min). The ratios of fibre to pesticides were determined in omnivorous diets. In this model, the binding capacity of lignin was equal to hemicellulose for PER, AZM and CLP, but it was significantly higher for CKL. Hemicellulose bound more CKL, AZM and CLP than did cellulose. Although pectin appreciably decreased all pesticides, its effect was lower than other fibres with one exception--cellulose-CKL. In the presence of equal amounts of fibre, lignin exerted the most significant effect on pesticide solubility. Hemicellulose and cellulose bind to the same extent PER and AZM. The effect of pectin was significant only on CKL and AZM when compared to the control.

Adult↗

Oxidative liver DNA damage in rats treated with pesticide mixtures.

Oxidative damage was quantified in the liver of rats by measuring the levels of 8-OH-2-deoxyguanosine (8-OH-2DG) relative to 2-deoxyguanosine in DNA after treating rats for 10 days at a total dose of 1 mg/kg/day with a mixture of the 15 pesticides most commonly found in Italian foods (comprised of dithiocarbamate, benomyl, procymidone, methidathion, chlorpyrifos-ethyl, parathion-methyl, chlorpropham, parathion, vinclozolin, chlorfenvinphos, pirimiphos ethyl, thiabendazole, fenarimol, diphenylamine and chlorothalonil). We fractionated this pesticide mixture into subgroups in order to determine which molecules, if any, induced DNA oxidative damage. The administration of diphenylamine (0.09-1.4 mg/kg/day) and chlorothalonil (0.13-1 mg/kg/day) induced a dose-dependent increase in 8-OH-2DG levels in liver DNA. The other 13 pesticides of the mixture on the contrary, did not produce oxidative liver DNA damage. These results indicate that the toxicity of low doses of pesticide mixtures present in food might be further reduced by eliminating diphenylamine and chlorothalonil.

Administration, Oral↗

The multidrug resistance-associated protein 1 transports methoxychlor and protects the seminiferous epithelium from injury.

We examined the ability of the multidrug resistance-associated protein 1 (MRP1/ABCC1) to transport pesticides, as this transporter mediates the cellular efflux of a variety of xenobiotics, typically as glucuronide, sulfate, or glutathione conjugates. NIH3T3 cells stably expressing MRP1 were 3.37-fold more resistant to the toxicity of fenitrothion, 3.12-fold more resistant to chlorpropham, and 2.5-fold more resistant to methoxychlor, a pesticide with estrogenic and anti-androgenic metabolites. The cells expressing MRP1 also eliminated methoxychlor two times more rapidly than their mock-transfected counterparts. We then examined whether mrp1 expression could alter the toxicity of methoxychlor in vivo using male FVB/mrp1 knockout mice (FVB/mrp1-/-). Both control and knockout mice were fed 25 mg/kg methoxychlor in honey for 39 days, and its effects on testicular morphology were examined. Methoxychlor treatment did not significantly affect testicular morphology in the FVB mice, but markedly reduced the number of developing spermatocytes in the FVB/mrp1-/- mice. These results suggest that MRPI may play a role in protecting the seminiferous tubules from methoxychlor-induced damage.

3T3 Cells↗

In-tube solid-phase microextraction coupled to capillary LC for carbamate analysis in water samples.

Recently, the on-line sample preparation technique, intube solid-phase microextraction (SPME), was successfully implemented with a Hewlett-Packard 1100 HPLC system for analysis of carbamates in water samples. This paper describes the coupling of in-tube SPME to capillary LC and explores its utility as a sample preparation method in that format, relative to conventional LC. The Hewlett-Packard HPLC system was upgraded to a capillary LC system using commercially available accessories from LC Packings. The combination of in-tube SPME with a capillary LC system was expected to build on the merits of both in-tube SPME and the capillary LC to generate a sensitive method with an easy, effective, and efficient sample preparation. Due to the relatively large effective injection volume of the in-tube SPME technique (30-45 microL), on-column focusing was employed in order to achieve good chromatographic efficiency. Excellent sensitivity was achieved with very good method precision. For all carbamates studied, the RSD of retention time was between 0.5 and 0.8% under 4 microL/min microgradient conditions. The RSD of peak area counts was between 1.5 and 4.6%. The detection limits for all carbamates studied were less than 0.3 microg/L and, for carbaryl, just 0.02 microg/L (20 ppt). Compared with the conventional in-tube SPME/LC method, the LODs were lowered for carbaryl, propham, methiocarb, promecarb, chlorpropham, and barban, by factors of 24, 45, 42, 81, 62, and 56, respectively. The optimized method was successfully applied to the analysis of carbamates in surface water samples.

Carbamates↗

Canadian Total Diet Study in 1998: pesticide levels in foods from Whitehorse, Yukon, Canada, and corresponding dietary intake estimates.

The Canadian Total Diet Study is a national survey to determine the level of chemical contaminants in the Canadian food supply. Food samples were collected from Whitehorse, Yukon, supermarkets as part of the study in 1998. Whitehorse was chosen as a sampling centre, despite its small population (n = 19,000), to determine if residue levels were different in foods available in northern communities relative to levels observed in previous studies in the more populated south. Foods were prepared as for consumption before pesticide residue analysis. Residue levels observed in most foods were similar to levels observed in samples from previous surveys from southern Canadian cities. Malathion and DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), a transformation product of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl(ethane), were the two most frequently detected compounds (26.4 and 25.8%, respectively). The majority of pesticides, however, had a detection frequency of < 5%. In general, pesticides in food composites were well below maximum residue limits established in the Canadian Food and Drug Regulations. Chlorpropham and captan had the highest dietary intakes (2.16 and 1.94 micrograms (kg body weight-day)-1, respectively), based on the results from Whitehorse. No dietary intakes above the acceptable daily intakes, however, were observed for any of the 39 pesticides investigated in any age-sex category, where an acceptable daily intake has been proposed.

Adolescent↗

Determination of commonly used herbicides in surface water using solid-phase extraction and dual-column HPLC-DAD.

The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C(18)) Empore extraction disks, octadecyl (C(18)), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C(18) and CN) to confirm identification. Analytical separation was performed simultaneously on C(18) and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C(18) disks, from 75.1% to 100.0% for C(18) cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025--0.4 microg L(-1). The limits of detection were 0.012--0.035 microg L(-1).

Chromatography, High Pressure Liquid↗

A sampling and analytical method for the simultaneous determination of multiple organonitrogen pesticides in air.

An air sampling and analytical method was developed for organonitrogen pesticides using a combined filter and XAD-2 sorbent sampler and high performance liquid chromatography-ultraviolet detection. The method was evaluated for 14 organonitrogen pesticides by National Institute for Occupational Safety and Health evaluation guidelines and procedures. Evaluation experiments addressed limits of detection and quantitation, analytical recovery, sampler capacity, sample stability, and precision and bias over a range of 12 to 240 micrograms per sample. Samples were stable when stored for up to 30 days under either ambient or refrigerated conditions. Based on the finding of this work, 10 of the 14 compounds studied (aldicarb, captan, carbaryl, carbofuran, chlorpropham, diuron, formetanate, methiocarb, oxamyl, propham) can be successfully determined simultaneously using one method with an accuracy of better than +/- 25% of the true value with 95% confidence. Two other compounds (carbendazim/benomyl, methomyl) can be measured with the same accuracy over a more limited concentration range. The remaining two compounds (propoxur, thiobencarb) may meet this criterion, but additional samples would need to be included in the data analysis. With the current data, these two compounds can be determined with an accuracy of better than +/- 27% of the true value with 95% confidence.

Agricultural Workers' Diseases↗

Biomonitoring of arylamines: hemoglobin adducts of urea and carbamate pesticides.

Hemoglobin adducts of aromatic amines released from pesticides were investigated. Female Wistar rats were dosed orally with pesticides up to 1 mmol/kg body weight. Blood was obtained after 24 h, hemoglobin isolated and hydrolyzed in 1 NaOH. The amines were extracted and quantified by gas chromatography with nitrogen-specific or mass-selective detection. The following binding indices [HBI, hemoglobin binding index = binding (mmol/mol Hb) per dose (mmol/kg)] were obtained: pesticide (arylamine): linuron, diuron (3,4-dichloroaniline) 0.8 and 4.5 respectively; monuron, monolinuron (4-chloroaniline) 39 and 55 respectively; chlorpropham (3-chloroaniline) 2.9; chlordimeform (4-chloro-o-toluidine) 2.4; propham (aniline) 2.4. With vinclozoline and iprodione (3,5-dichloroaniline) and quintozene (pentachloroaniline) no adducts could be found. The results demonstrate the possible use of arylamine-hemoglobin adducts for measuring the bioavailability of potentially hazardous components of pesticides and the extent to which they are formed and metabolically activated.

Animals↗

Assay of linuron and a pesticide mixture commonly found in the Italian diet, for promoting activity in rat liver carcinogenesis.

The herbicide linuron and a mixture of 15 pesticides commonly found in the Italian diet have been assayed for promoting activity in rat liver carcinogenesis. Composition of the pesticide mixture was: benomyl (19.55%); dithiocarbamates (20.67%); thiabendazole (14.94%); diphenylamine (14.25%); chlorthalonil (13.13%); procymidone (7.96%); fenarimol (1.95%); chlorpropham (0.70%); vinchlozolin (0.28%); methidathion (2.37%); chlorpyriphos-ethyl (2.09%); parathionmethyl (1.00%); chlorfenvinphos (0.27%); parathion (0.70%); pyrimiphos-ethyl (0.14%). To determine promoting activity we evaluated induction of preneoplastic foci in diethylnitrosamine-initiated hepatocytes, by positive gammaglutamyl-transpeptidase (GGTase) staining in liver slides, and peroxisome proliferation by peroxisomal-dependent catalase and palmitoyl-CoA-oxidase dosage. For the assay, groups of male Sprague-Dawley rats were initiated with 100 mg/kg diethylnitrosamine intraperitoneally and, one week later, given 150 mg/kg/day linuron or 10 mg/kg/day pesticide mixture, administered by gavage three days a week. All rats were 2/3 hepatectomized at the beginning of the 3rd week. All treatments were terminated at the end of the 8th week, and the rats were sacrificed one week later. No significant increases in number and area (mm2) per slide unit area (cm2) of GGTase-positive foci could be observed in linuron-treated rats (5.84 +/- 1.62/cm2; 0.139 +/- 0.041 mm2/cm2) with respect to controls only initiated with diethylnitrosamine (4.47 +/- 1.30/cm2; 0.182 +/- 0.078 mm2/cm2). After treatment with the pesticide mixture, the number of preneoplastic foci was instead significantly increased (6.91 +/- 2.05/cm2) although the area was not (0.188 +/- 0.128 mm2/cm2). Moreover, no increases in the peroxisome proliferation enzymatic markers were observed in either treated groups. The results imply a possible carcinogenic risk for the population stemming from promoting activities of pesticide mixtures.

Animals↗

Second-order model to predict microbial degradation of organic compounds in natural waters.

The reliability of second-order rate constants for assessing microbial degradation kinetics in natural waters was examined by using three compounds that undergo hydrolytic degradation. The butoxyethyl ester of 2,4-dichlorophenoxyacetic acid was studied in water samples from 31 sites, malathion was examined in water from 14 sites, and chlorpropham was studied in samples from 11 sites. The coefficient of variation for rate constants for each compound was less than 65% over all sites. Additional studies indicated that the rate conformed to second-order kinetics; that is, the rate was proportional to both bacterial and xenobiotic concentrations.

Journal Article↗

Selectivity lists of pesticides to beneficial arthropods for IPM programs in carrot--first results.

In order to improve IPM programs in carrot, 7 fungicides, 12 herbicides and 9 insecticides commonly used in Belgium were tested for their toxicity towards five beneficial arthropods representative of most important natural enemies encountered in carrot: parasitic wasps - Aphidius rhopalosiphi (De Stefani-Perez) (Hym., Aphidiidae), ladybirds - Adalia bipunctata (L.) (Col., Coccinellidae), hoverfly - Episyrphus balteatus (Dipt.. Syrphidae), rove beetle - Aleochara bilineata (Col., Staphylinidae) and carabid beetle - Bembidion lampros (Col., Carabidae). Initialy, all plant protection products were tested on inert substrate glass plates or sand according to the insect. Products with a corrected mortality (CM) or a parasitism reduction (PR) lower than 30% were kept for the constitution of positive list (green list). The other compounds were further tested on plant for A. rhopalosiphi, A. bipunctata, E. balteatus and soil for B. lampros and A. bilineata. With these extended laboratory tests results, products were listed in toxicity class: green category [CM or PR < or = 30%], yellow category [30% < CM or PR < or = 60%] and orange category [60% < CM or PR < or = 80%]. Products with toxicity higher than 80% on plants or that reduce parasitism more than 80% on soil were put in red category and are not recommended to Integrated Pest Management programs in carrot. Results showed that all fungicides tested were harmless to beneficials except Tebuconazole, which was slightly harmful for A. bipunctata. Herbicides were also harmless for soil beneficials, except Chlorpropham. This product was very toxic on sand towards A. bilineata and must be tested on soil. All soil insecticides tested were very toxic for ground beneficials and considered as non-selective. Their use in IPM is subject to questioning in view of negative impacts on beneficials. Among foliar insecticides, Dimethoate and Deltamethrin are not recommended for IPM because their high toxicity for all beneficials. The other foliar insecticides were more selective; any of them were harmless for all species tested.

Animals↗

Effect of inhibitors of plant cell division on mammalian tumor cells in vitro.

We studied the activity of 14 compounds, all of which have been shown to interfere in plant cell division, in two animal tumor cell cultures, EL-4 and L1210. Four compounds [propham, chlorpropham, bensulide S-(O,O-diisopropylphosphorodithioate) ester of N-(2-mercaptoethyl)benzenesulfonamide), and siduron] had a 50% inhibitory dose less than 10(-4) M; six [2,3,5-triiodobenzoic acid, (2,4-dichlorophenoxy)acetic acid, bromacil, (2,4,5-trichlorophenoxy)acetic acid, naptalam, and (4-chloro-2-methylphenoxy)acetic acid] had a 50% inhibitory dose between 10(-4) and 10(-3) M, and the remaining four 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, eptam, maleic hydrazide, and 4-(methylsulfonyl)-2,6-dinitro-N,N,-dipropylaniline] had a 50% inhibitory dose at higher than 10(-3) M. There was a significant correlation between the effect on the two cell lines as well as between the inhibition of cell proliferation and that of thymidine and leucine uptake. More detailed study of cell proliferation and leucine and thymidine uptake for bensulide and 2,3,5-triiodobenzoic acid revealed a dose-response pattern of inhibition starting shortly after exposure of the cells to the compounds. These results indicate that some inhibitors of plant cell division are capable of inhibiting the proliferation of animal tumor cells.

Animals↗

Effect of a mixture of 15 commonly used pesticides on DNA levels of 8-hydroxy-2-deoxyguanosine and xenobiotic metabolizing enzymes in rat liver.

The level of 8-OH-2-deoxyguanosine in rat liver DNA was measured as an index of oxidative damage after treating rats for 10 days at a dose ranging from 0.75 to 10 mg/kg with a mixture of 15 pesticides (dithiocarbamate, benomyl, thiabendazole, diphenylamine, chlorthalonil, procimidone, methidathion, chlorpyrifos-ethyl, fenarimol, parathion-methyl, chlorpropham, parathion, vinclozolin, chlorfenvinphos, pirimiphos-ethyl) commonly found in foods of central Italy. At the doses of 0.75 and 1 mg/kg DNA levels of 8-OH-2-deoxyguanosine were significantly increased relative to controls, whereas at higher doses (2.5, 5, 10 mg/kg) the levels returned to control values. The administration of the pesticide mixture dose dependently reduced benzo(a)pyrene hydroxylase, N-demethylase activities, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and thiol transferase activities in the liver. The results show that the pesticide mixture induced free radical DNA damage at low doses. However, at higher doses it produced a depression of cellular metabolism, inhibiting a further expression of oxidative damage.

8-Hydroxy-2'-Deoxyguanosine↗

Reference Raman spectra of eleven miscellaneous pesticides.

The Raman spectra of ICP (propham), CIPC (chlorpropham), carbaryl, EPTC (ethyl N,N-dipropyl (3-chlorophenyl) carbamate), pebulate, CDEC (2-chloroallyl diethyldithiocarbamate), thiram, maneb, zineb, ferbam, and nicotine have been recorded. These spectra are presented, along with tables giving values for the frequencies.

Insecticides↗

Experimental manipulation of gamma-tubulin distribution in Arabidopsis using anti-microtubule drugs.

gamma-Tubulin-specific antibodies stain the microtubule (Mt) arrays of Arabidopsis suspension cells in a punctate or patchy manner. During division, staining of kinetochore fibers and the phragmoplast is extensive, except in the vicinity of the plus ends at the metaphase plate and cell plate. gamma-Tubulin localization responds to low levels of colchicine, with staining receding farther toward the minus (pole) ends of kinetochore fibers. At higher drug concentrations, gamma-tubulin also associates with abnormal Mt foci as well as with the surface of the daughter nuclei facing the phragmoplast. During UV-induced recovery from colchicine, gamma-tubulin increases along the presumptive minus ends of mitotic Mts as well as the phragmoplast near the daughter nuclei. With CIPC, immunostaining is concentrated around the centers of focal Mt arrays in multipolar spindles. In the presence of taxol, Mts are more prominent but the mitotic apparatus and phragmoplast are abnormal. As with CIPC, gamma-tubulin is concentrated at focal arrays. Increased punctate staining is also present in interphase arrays, with fluorescent dots often located at the ends of Mts. These results support a preferential association between gamma-tubulin and Mt minus ends, but are also consistent with more general binding along the walls of Mts. Thus, minus ends (and Mt nucleation sites) may be present throughout plant Mt arrays, but gamma-tubulin may also serve another function, such as in structural stabilization.

Amino Acid Sequence↗

The role of actin filaments in the gravitropic response of snapdragon flowering shoots.

The involvement of the actin and the microtubule cytoskeleton networks in the gravitropic response of snapdragon ( Antirrhinum majus L.) flowering shoots was studied using various specific cytoskeleton modulators. The microtubule-depolymerizing drugs tested had no effect on gravitropic bending. In contrast, the actin-modulating drugs, cytochalasin D (CD), cytochalasin B (CB) and latrunculin B (Lat B) significantly inhibited the gravitropic response. CB completely inhibited shoot bending via inhibiting general growth, whereas CD completely inhibited bending via specific inhibition of the differential flank growth in the shoot bending zone. Surprisingly, Lat B had only a partial inhibitory effect on shoot bending as compared to CD. This probably resulted from the different effects of these two drugs on the actin cytoskeleton, as was seen in cortical cells. CD caused fragmentation of the actin cytoskeleton and delayed amyloplast displacement following gravistimulation. In contrast, Lat B caused a complete depolymerization of the actin filaments in the shoot bending zone, but only slightly reduced the amyloplast sedimentation rate following gravistimulation. Taken together, our results suggest that the actin cytoskeleton is involved in the gravitropic response of snapdragon shoots. The actin cytoskeleton within the shoot cells is necessary for normal amyloplast displacement upon gravistimulation, which leads to the gravitropic bending.

Actins↗