Blood and hair manganese concentrations in pregnant women from the infants' environmental health study (ISA) in Costa Rica.

Manganese (Mn), an essential nutrient, is a neurotoxicant at high concentrations. We measured Mn concentrations in repeated blood and hair samples collected from 449 pregnant women living near banana plantations with extensive aerial spraying of Mn-containing fungicide mancozeb in Costa Rica, and examined environmental and lifestyle factors associated with these biomarkers. Mean blood Mn and geometric mean hair Mn concentrations were 24.4 µg/L (8.9-56.3) and 1.8 µg/g (0.05-53.3), respectively. Blood Mn concentrations were positively associated with gestational age at sampling (ß = 0.2; 95% CI: 0.1 to 0.2), number of household members (ß = 0.4; 95% CI: 0.1 to 0.6), and living in a house made of permeable and difficult-to-clean materials (ß = 2.6; 95% CI: 1.3 to 4.0); and inversely related to smoking (ß = -3.1; 95% CI: -5.8 to -0.3). Hair Mn concentrations were inversely associated with gestational age at sampling (% change = 0.8; 95% CI: -1.6 to 0.0); and positively associated with living within 50 m of a plantation (% change = 42.1; 95% CI: 14.2 to 76.9) and Mn concentrations in drinking water (% change = 17.5; 95% CI: 12.2 to 22.8). Our findings suggest that pregnant women living near banana plantations aerially sprayed with mancozeb may be environmentally exposed to Mn.

Dissipation of residues of mancozeb and metalaxyl in tomato (Solanum lycopersicum L.).

Dissipation of mancozeb and metalaxyl in tomato was estimated following four applications of a combination formulation Ridomil MZ (mancozeb 64% + metalaxyl 8%) at 0.25 and 0.50% at 10 days interval by carbon disulphide evolution method and gas liquid chromatography with nitrogen phosphorous detector, respectively. Half-life periods for mancozeb were 3.76 and 4.14 days, whereas for metalaxyl these values were 1.29 and 0.41 days at single and double the application rates, respectively. Residues of mancozeb dissipated below limit of quantification (LOQ) of 0.25 mg kg(-1) after 10 and 15 days at single and double the application dosage, respectively. Similarly, residues of metalaxyl took 3 and 5 days to reach LOQ of 0.02 mg kg(-1), at single and double dosages, respectively.

Identification and quantitation by high-performance liquid chromatography of mancozeb following derivatization by 1,2-benzenedithiol.

Ethylenebisdithiocarbamate (EBDC) fungicides are the most important class of organic fungicides and exhibit a high degree of carcinogenicity, mutagenicity, and neurotoxicity. For that reason, the safe application of these fungicides in practice requires a convenient method for their determination, applicable to biological fluids. We describe a high-performance liquid chromatography (HPLC) assay. After elimination of the metal which defines the product (maneb, mancozeb, zineb.) with EDTA, the resulting EBDC is derivatized with 1,2-benzenedithiol to yield a cyclocondensation product, 1,3-benzodithiole-2-thione, which can then be quantitated by reversed-phase HPLC at 365 nm using a microBondapak C18 column. The mobile phase was methanol/H2O (70:30, v/v). The assay was linear from 0.25 to 100 microg/mL. Within- and between-day precision and accuracy for this assay were better than 9% and 6%, respectively. The lower limits of detection and quantitation were estimated to be 0.1 and 0.25 microg/mL, respectively. This simple new method has been applied to determine mancozeb concentration in rat urine samples from urinary excretion studies.

Ethylenethiourea in urine as an indicator of exposure to mancozeb in vineyard workers.

In the present study, the personal exposure to mancozeb and/or ethilenethiourea (ETU) in 13 Italian vineyard workers and in 13 subjects without occupational exposure to pesticides was investigated. With this aim, the level of ETU in urine and the dermal exposure to mancozeb were determined. Baseline urinary ETU results were lower than the analytical limit of detection for all controls (<0.5 microg/g creatinine) and for ten workers (median <0.5, range <0.5-3.4 microg/g creatinine). In workers, urinary ETU was significantly increased at the end of shift (2.5, <0.5-95.2 microg/g creatinine) compared with baseline levels. End-shift urinary ETU was higher in operators using open tractors (n=7) than in those using closed tractors (n=5) (16.2 vs. 2.4 microg/g creatinine), but the difference was not significant (P=0.073). End-shift urinary ETU was positively correlated with dermal exposure to mancozeb determined both over the clothes and on the skin (Spearman's rho=0.770 and 0.702, P=0.009 and 0.024, respectively). Wine consumption positively influenced the excretion of ETU.

Evaluation of genotoxicity of captan, maneb and zineb in the wing spot test of Drosophila melanogaster: role of nitrosation.

The wing spot test in Drosophila melanogaster is a suitable system for the analysis of genotoxic activity of compounds that need metabolic transformation to render them active. We have analysed the genotoxicity of three fungicides for which it was reported that the metabolic processes taking place in vivo may determine their activity. The compounds analysed are captan, maneb, zineb and ethylenethiourea (ETU) (a metabolic derivative of ethylenebisdithiocarbamates like maneb and zineb). We have also evaluated the ability of ETU to form genotoxic derivatives in vivo analysing this compound in combined treatments with sodium nitrite. Both standard and high bioactivation NORR strains have been used. Captan, usually considered a mutagen in vitro but a non-mutagen in vivo, gave negative results in the wing spot test with both crosses. Positive results were obtained for maneb in the standard cross and for ETU in both the standard and the high bioactivation cross. The genotoxicities of maneb and ETU were higher when treatments were made on media in which nitrosation is favoured. A low absorption of the fungicide and an inefficient availability of the compound in the target may explain negative results obtained with zineb in both crosses. The results obtained in this study with the wing spot test demonstrate once again the suitability of this in vivo assay, in which absorption, distribution and metabolism processes take place, for the evaluation of genotoxicity of compounds to which humans are exposed.

Toxicity of the dithiocarbamate fungicide mancozeb to the nontarget soil nematode, Caenorhabditis elegans.

We have previously shown that the dithiocarbamate fungicide, Mancozeb, strongly induces lacZ reporter expression from an endogenous heat-shock promoter (hsp16) in the PC72 transgenic strain of the nematode Caenorhabditis elegans. Such evidence of organismal stress, in a nontarget species at subapplication concentrations, was much less apparent for the related fungicide, Maneb, which only weakly induced reporter expression. We now show that reporter induction by Mancozeb is marginal (<60%) after a few hours' exposure, but increases substantially (to almost 10-fold) after overnight exposure. In conjunction with our previous results using intermediate exposure periods, this suggests that the factor limiting reporter responses is likely to be a slow rate of uptake and/or metabolism of the fungicide. We confirm that a potentially toxic metabolite of dithiocarbamate fungicides, namely ethylenethiourea (ETU), has minimal toxicity toward C. elegans, even after prolonged exposure at high concentrations. We demonstrate that exposure to Mancozeb (but not ETU) significantly inhibits larval growth in C. elegans, although this parameter is not markedly more sensitive than reporter induction as a toxicological endpoint. Finally, we have used two-dimensional electrophoresis to show that high concentrations of both Maneb and Mancozeb drastically simplify the protein spot profile compared with controls. However, only in the latter case is there evidence of novel proteins being induced. Both fungicides appear toxic to C. elegans, but only Mancozeb induces a strong heat-shock response.

The fate and persistence of zineb, maneb, and ethylenethiourea on fresh and processed tomatoes.

Tomatoes grown under greenhouse conditions were sprayed with radiolabelled maneb and zineb to determine the extent of degradation of these fungicides to ethylenethiourea (ETU) and to study the persistence of ETU on the fruits. The total (14C) residues decreased from 0.082 mg/kg and 0.11 mg/kg at day 0 to 0.023 mg/kg and 0.05 mg/kg at day 20, on zineb- and maneb-treated fruits, respectively. This reduction was mainly due to the rapid growth of the fruits. ETU residues on tomato fruits were found to decline with time. A sharp reduction in ETU content was observed during the first 24 h after treatment, followed by a slow decline in the following 5 days. ETU content was reduced by about 80% by day 20 after the fungicide application, and the concentration of EU, the major degradation product of ETU, doubled during the same period. Studies with tomatoes fortified with (14C) ETU (0.006 mg/kg) prior to processing into tomato paste showed that 70% of the radioactivity was lost during washing of the tomatoes in water. Further losses of ETU occurred during boiling of the juice (6%) and during storage of the tomato paste for a period of 3 weeks (3%).

The accumulation and histological effects of organometallic fungicides propineb and maneb in the livers of pregnant rats and their offspring.

Dithiocarbamate propineb and maneb are organometal fungicides, which are widely used for the control of diseases in plants. Female Wistar rats were exposed orally to 200 and 400 ppm propineb (Zn-containing dithiocarbamate) and 250 ppm maneb (Mn-containing dithiocarbamate), from the 6th day of gestation up to birth. We found that the body weights of both newborn litters and their fungicide-treated mothers were lower than those of controls. Histological examination of the livers of fungicide-treated pregnant females and the offspring showed a variety of histopathological effects. Moreover, the analysis of Zn and Mn concentrations in the livers of pregnant females exposed to organometallic fungicides during pregnancy demonstrated that the metal concentrations in the liver were higher than those of controls. Similarly, the hepatic metal concentrations were significantly increased in the litters, indicating the transplacental passage of the organometallic fungicides.

The accumulation and histological effects of organometallic fungicides Propineb and Maneb in the kidneys of fetus and female rats during pregnancy.

Dithiocarbamate propineb and maneb are organometal fungicides, which are widely used for the control of diseases in plants. Female Wistar rats were exposed orally to 200 and 400 ppm propineb and 250 ppm maneb, from the sixth day of gestation up to birth. We found that the body weights of both one-day old litters and their fungicide-treated mothers were lower than those of controls. Histological examination of the kidneys of fetus and fungicide-treated pregnant females showed a variety of histopathological effects. Moreover, the analysis of zinc (Zn) and manganese (Mn) concentrations (using inductively coupled plasma-atomic emission spectrometry) in the kidneys of pregnant females exposed to organometallic fungicides during pregnancy demonstrated that the metal concentrations in the kidney were higher than those of controls. However, the renal metal concentrations were significantly increased in the litters subjected to the fungicides during gestation, indicating that high levels of the trace metals in the organ of fetus may well be due to the fungicides easily passing the placental barrier.

Environmental and biological monitoring of exposure to mancozeb, ethylenethiourea, and dimethoate during industrial formulation.

The results of environmental (11 subjects) and biological (57 subjects) monitoring of exposure to mancozeb, ethylenethiourea (ETU), and dimethoate are reported for employees of a firm producing commercial formulations containing these active ingredients. Urinary excretion [GM(GSD)] of ETU (microg/g creatinine) and alkylphosphates [dimethylphosphate (DMP) + dimethylthiophosphate (DMTP) + dimethyldithiophosphate (DMDTP)] (nmol/g creatinine) was 65.3(4.8) and 419.2(2.1), respectively, for employees engaged in the formulation of a product containing 80% mancozeb (n = 9), 36.6(1.9) and 296.4(2.4) for those formulating a product containing 35% mancozeb (n = 9), 9.5(6.1) and 1022.4(3.0) for those engaged in plant maintenance and internal transport of materials (n = 6), 10.3(4.2) and 322.8(3.3) for those engaged in packaging the mancozeb formulations (n = 16), 4.4(3.3) and 2545.4(3.9) for those formulating a product containing 40% dimethoate (n = 11), and 3.0(2.7) and 871.7(3.3) for those bottling the same dimethoate formulation (n = 10). Air concentrations (microg/m3) ranged from 25.3 to 194.4 for dimethoate, from 0.2 to 1.3 for ETU, and from 139.9 to 949.0 for mancozeb. Urinary excretion of ETU and alkylphosphates showed a significant correlation with mancozeb (r2 = .971), and ETU (r2 = .858), and dimethoate (r2 = .955) contamination of the hands. Potential dose estimates showed that the potential respiratory doses of mancozeb and dimethoate accounted, on the average, for 38% of the total potential dose. The potential respiratory dose of ETU was 7% of the total potential dose. Total estimated absorption did not exceed the accepted daily dose (ADI) for ETU and mancozeb, but the ADI for dimethoate was exceeded. Serum and erythrocyte cholinesterase activities in workers formulating dimethoate products were not significantly different before and after exposure.

Radiotracer study on mancozeb residues in tomato plants.

A study on the persistence, residues and residue distribution of mancozeb in tomato plant-soil system, as well as effects of cooking on transformation of residual mancozeb were carried out with radiotracer technique. Half-life values for total mancozeb residues on tomato leaves and in soil were observed to be 9.5 and 7.6 days, respectively. The results also suggested that mancozeb residues in soil were readily uptaken by plants and leach to soil layer as deep as 28cm within two weeks, although over 90% of the residues remained in the upper layer (0-6cm) of the soil. Translocation of the residues of mancozeb, especially the water soluble metabolites including ETU, throughout the plants could be one of the factors responsible for the contamination of tomato fruits. Deposit of sprayed mancozeb on the fruit skin was another important factor leading to the contamination of fruits. Fruit skin contained higher levels of residues than the pulp. Washing with water could remove more than 50% of the residues on the skin. It was also found that 20-30% of the residual mancozeb degraded to ETU during cooking process. The tomatoes should be washed to reduce the residues of the fungicide and ETU in food.