Assessment of Mancozeb Exposure, Absorbed Dose, and Oxidative Damage in Greenhouse Farmers.

Mancozeb (MNZ) is a fungicide commonly employed in many countries worldwide. This study assesses MNZ absorption dynamics in 19 greenhouse farmers, specifically following dermal exposure, aiming to verify the efficacy of both preventive actions and protective equipment. For data collection, a multi-assessment approach was used, which included a survey to record study population features. MNZ exposure was assessed through the indirect measurement of ethylene thiourea (ETU), widely employed as an MNZ biomarker. The ETU concentration was measured with the patch method, detecting environmental ETU trapped in filter paper pads, applied both on skin and working clothes, during the 8 h work shift. Urine and serum end-of-shift samples were also collected to measure ETU concentrations and well-known oxidative stress biomarkers, respectively, namely reactive oxygen metabolites (ROMs), advanced oxidation protein products (AOPPs), and biological antioxidant potential (BAP). It was observed that levels of ETU absorbed and ETU excreted were positively correlated. Additionally, working clothes effectively protected workers from MNZ exposure. Moreover, following stratification of the samples based on the specific working duty (i.e., preparation and spreading of MNZ and manipulation of MNZ-treated seedlings), it was found that the spreading group had higher ETU-related risk, despite lower chronic exposure levels. AOPP and ROM serum levels were higher in MNZ-exposed subjects compared with non-exposed controls, whereas BAP levels were significantly lower. Such results support an increase in the oxidative stress upon 8 h MNZ exposure at work. In particular, AOPP levels demonstrated a potential predictive role, as suggested by the contingency analysis results. Overall, this study, although conducted in a small group, confirms that ETU detection in pads, as well as in urine, might enable assessment of the risk associated with MNZ exposure in greenhouse workers. Additionally, the measurement of circulating oxidative stress biomarkers might help to stratify exposed workers based on their sensitivity to MNZ. Pivotally, the combination of both ETU measurement and biological monitoring might represent a novel valuable combined approach for risk assessment in farmhouse workers exposed to pesticides. In the future, these observations will help to implement effective preventive strategies in the workplace for workers at higher risk, including greenhouse farmers who are exposed to pesticides daily, as well as to clarify the occupational exposure levels to ETU.

Prenatal pesticide exposure and respiratory health outcomes in the first year of life: Results from the infants' Environmental Health (ISA) study.

BACKGROUND: Growing evidence suggests that pesticide exposure may influence respiratory health, but data in young children are very limited. We examined the association of prenatal pesticide exposure with lower respiratory tract infections (LRTIs) and wheeze at one year of age in children from the Infants' Environmental Health (ISA) study in Costa Rica. METHODS: We measured seven pesticide metabolites, including ethylenethiourea (ETU, metabolite of mancozeb), in maternal urine samples collected repeatedly during pregnancy. For each woman, we averaged pesticide concentrations during each half of pregnancy (≤20 and >20 weeks of gestation) and across repeated samples collected over the course of pregnancy. We collected information about LRTIs (n = 355) and wheezing (n = 272) during the first year of life from mothers when their children were 11-19 months old. We fit multivariable logistic regression models using high (quartile 4) vs. low (quartiles 1-3) urinary pesticide concentrations as exposures and adjusted models for maternal age, education, parity, gestational age at birth, and child sex. RESULTS: Ten percent of the children had at least one LRTI and 39% had at least one episode of wheezing during their first year of life. Median (25-75th percentile) specific gravity-corrected urinary ETU concentrations during the first half, second half, and over the course of pregnancy were 3.4 (2.1-5.0), 3.3 (2.2-4.7), and 3.4 (2.4-5.0) ng/mL, respectively. We observed that high urinary ETU concentrations during the first half of pregnancy were associated with increased odds of LRTI (OR = 2.45; 95% CI: 0.96, 6.26), whereas high urinary ETU concentrations during the second half of pregnancy were associated with decreased odds of wheezing (OR = 0.50; 95% CI: 0.26, 0.96). We found that the association between high urinary ETU concentrations during the first half of pregnancy and LRTIs persisted among mother-child pairs with either high or low ETU concentrations during the second half. In contrast, the association of high urinary ETU concentrations during the second half of pregnancy with wheezing was attenuated when we simultaneously adjusted for urinary ETU concentrations during the first half. We observed null associations between other pesticide metabolites measured during pregnancy and respiratory outcomes. CONCLUSIONS: Our data indicate that exposure to mancozeb/ETU during the first half of pregnancy may be associated with respiratory outcomes in the first year of life.

Exposure duration and absorbed dose assessment in pesticide-exposed agricultural workers: Implications for risk assessment and modeling.

INTRODUCTION: Absorbed dose assessment from dermal exposure involves multiplying skin contamination by the dermal absorption coefficient, which is usually defined for the standard workday of 8 h. This strategy may suffer from limitations when the duration of exposure is extremely variable, such as in agricultural exposure to pesticides. OBJECTIVES: The aim of this study was to estimate the dose of mancozeb absorbed by agricultural pesticide applicators in a typical working day considering the real duration of exposure, to compare these estimates with those coming from the use of the Fixed Fractional Approach, and to assess the suitability of the dose estimates in the interpretation of biological monitoring results. METHODS: In a series of real-life field studies on 29 workers applying mancozeb in vineyards for 38 work days, three sets of data were collected: information regarding work activities for each work day, potential (on clothes) and actual skin exposure using the "patch" methodology, and excretion of ethylenethiourea (ETU) in the 24-h pre-exposure and 24-h post-exposure urine samples. The statistical analyses were done using the R Language and Environment for Statistical Computing. RESULTS: Accounting for the duration of exposure led to a substantial reduction in the absorbed dose estimates, compared to the estimates coming from the Fixed Fractional Approach. In particular, absorbed dose by the body, hands' and total absorbed dose were reduced by 50%, 81%, and 80% respectively. The body dose estimated considering both approaches still correlated better with post-exposure 24-h urine ETU levels than the hands' dose, although more than 90% of the estimated total absorbed dose comes from the hands. CONCLUSIONS: An accurate estimate of the absorbed dose, carried out considering the real duration of exposure, can result in a higher correlation with a biomarker of occupational exposure, such as urine ETU, or at least yield more accurate results. This can facilitate the interpretation of biological monitoring data in pesticide-exposed agricultural workers despite the absence of biological exposure limits. ETU should be evaluated as a potentially relevant source of exposure due to ethylenebisdithiocarbamates' (EBDCs) degradation in the formulated product or spray mixture.

Design of anti-thyroid drugs: Binding studies and structure determination of the complex of lactoperoxidase with 2-mercaptoimidazole at 2.30 Å resolution.

Lactoperoxidase (LPO) belongs to mammalian heme peroxidase superfamily, which also includes myeloperoxidase (MPO), eosinophil peroxidase (EPO), and thyroid peroxidase (TPO). LPO catalyzes the oxidation of a number of substrates including thiocyanate while TPO catalyzes the biosynthesis of thyroid hormones. LPO is also been shown to catalyze the biosynthesis of thyroid hormones indicating similar functional and structural properties. The binding studies showed that 2-mercaptoimidazole (MZY) bound to LPO with a dissociation constant of 0.63 µM. The inhibition studies showed that the value of IC50 was 17 µM. The crystal structure of the complex of LPO with MZY showed that MZY bound to LPO in the substrate-binding site on the distal heme side. MZY was oriented in the substrate-binding site in such a way that the sulfur atom is at a distance of 2.58 Å from the heme iron. Previously, a similar compound, 3-amino-1,2,4-triazole (amitrole) was also shown to bind to LPO in the substrate-binding site on the distal heme side. The amino nitrogen atom of amitrole occupied the same position as that of sulfur atom in the present structure indicating a similar mode of binding. Recently, the structure of the complex of LPO with a potent antithyroid drug, 1-methylimidazole-2-thiol (methimazole, MMZ) was also determined. It showed that MMZ bound to LPO in the substrate-binding site on the distal heme side with 2 orientations. The position of methyl group was same in the 2 orientations while the positions of sulfur atom differed indicating a higher preference for a methyl group.

Effects of hydrochemistry variables on the half-life of mancozeb and on the hazard index associated to the sum of mancozeb and ethylenethiourea.

Mancozeb is a dithiocarbamate non-systemic agricultural fungicide with multi-site, protective action. It helps to control many fungal diseases in a wide range of field crops, fruits, nuts, vegetables, and ornamental plants. We have investigated the stability profiles of mancozeb in aqueous solutions to determine the effect of pH, temperature and light on the degradation process of mancozeb. In addition, the toxicological risk for humans associated with the joint intake of mancoze7b and its final degradation product, ethylenethiourea (ETU), was calculated and modelled as a function of the experimental conditions. Stability study results showed a very low stability profile of mancozeb in all the aqueous solutions with rapid degradation that varied with experimental conditions. The process followed first order kinetics. The study of the degradation kinetics showed a significant effect of pH*temperature interaction on the degradation process. The results also expressed that light has a greater impact on the stability of mancozeb and the formation of ETU. The current study concludes that mancozeb is unstable in aqueous solutions, particularly at an acid pH, in addition to presenting both severe light and lower temperature sensitivity. The toxicological risk associated with mancozeb degradation increases with time and temperature, being higher at basic pH and in absence of light.

Isolation and characterization of antagonistic Bacillus strains capable to degrade ethylenethiourea.

In this study, more than 150 bacteria showing antagonistic properties against bacterial and fungal pathogens of the tomato plant were isolated and characterized. The most efficient agents against these phytopathogenic microorganisms belong to the genus Bacillus: the best biocontrol isolates were representatives of Bacillus subtilis, B. mojavensis and B. amyloliquefaciens species. They intensively produced fengycin or/and surfactin depsipeptide antibiotics and also proved to be excellent protease secretors. It was proved, that the selected strains were able to use ethylenethiourea (ETU) as sole nitrogen source. These antagonistic and ETU-degrading Bacillus strains can be applied as biocontrol and also as bioremediation agents.

A rapid and environmental friendly determination of the dithiocarbamate metabolites ethylenethiourea and propylenethiourea in fruit and vegetables by ultra high performance liquid chromatography tandem mass spectrometry.

Previous published methods for the analysis of ETU and PTU are time-consuming and furthermore use dichloromethane (DCM) for extraction or clean-up. This study details the development and validation of a rapid method that combines a simple extraction step with UHPLC-ESI(+)-MS/MS. This is the first application of UHPLC-MS/MS to analyse these compounds. Besides that, we replaced DCM with a more environmental-friendly solvent. The analytical performance was evaluated with the analysis of spiked celery samples at 50 µg kg(-1) (LOQ) and 300 µg kg(-1). The recoveries were between 65% and 90% for ETU and between 71% and 127% for PTU with RSDs in repeatability and reproducibility conditions below 10% for ETU. This method is rapid (a chromatographic run time of 2 min) and can easily be performed (no laborious clean-up). The presented method is environmental friendly with significant reduction in solvent consumption.

Changes in serum markers indicative of health effects in vineyard workers following exposure to the fungicide mancozeb: an Italian study.

The aim of this study was to investigate the health effects induced by exposure to the fungicide mancozeb in Italian vineyard workers. Ninety-three Italian subjects entered the study - 48 vine-growers intermittently exposed to mancozeb and 45 healthy controls. The subjects were investigated three times: before the seasonal application of pesticides (T0), 30 days after the beginning of the application period (T30), and 45 days after T0 (T45). At T0 the comparison between agricultural workers and controls showed a higher prevalence of cold or flu symptoms, a statistically significant lower percentage of monocytes, higher absolute count of T lymphocytes, CD4 and natural killer cells, and lower plasma levels of IgA and IgM in workers. Such differences were not confirmed at T30 and T45. In fact at T30 in exposed workers, besides a significant increase of urinary ethylenethiourea, confirming mancozeb exposure, T lymphocytes, CD4 and natural killer cells, IgA and IgM returned to values comparable to those observed in controls. Moreover, no other differences in clinical signs, haematological, and immune parameters, such as the immune functional capability evaluated as a response to hepatitis B vaccination, was observed. Altogether the differences between exposed and controls were not consistently correlated to any clinical impairment and suggest that the seasonal application of mancozeb does not pose a significant health risk to exposed subjects.

Method for determination of acephate, methamidophos, omethoate, dimethoate, ethylenethiourea and propylenethiourea in human urine using high-performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry.

Because of increasing concern about widespread use of insecticides and fungicides, we have developed a highly sensitive analytical method to quantify urine-specific urinary biomarkers of the organophosphorus pesticides acephate, methamidophos, omethoate, dimethoate, and two metabolites from the fungicides alkylenebis-(dithiocarbamate) family: ethylenethiourea and propylenethiourea. The general sample preparation included lyophilization of the urine samples followed by extraction with dichloromethane. The analytical separation was performed by high-performance liquid chromatography (HPLC), and detection by a triple quadrupole mass spectrometer with and atmospheric pressure chemical ionization source in positive ion mode using multiple reaction monitoring and tandem mass spectrometry (MS/MS) analysis. Two different Thermo-Finnigan (San Jose, CA, USA) triple quadrupole mass spectrometers, a TSQ 7,000 and a TSQ Quantum Ultra, were used in these analyses; results are presented comparing the method specifications of these two instruments. Isotopically labeled internal standards were used for three of the analytes. The use of labeled internal standards in combination with HPLC-MS/MS provided a high degree of selectivity and precision. Repeated analysis of urine samples spiked with high, medium and low concentration of the analytes gave relative standard deviations of less than 18%. For all compounds the extraction efficiency ranged between 52% and 63%, relative recoveries were about 100%, and the limits of detection were in the range of 0.001-0.282 ng/ml.

Reference values for ethylenethiourea in urine in Northern Italy: results of a pilot study.

This study was carried out to define reference values for urinary ethylenethiourea (ETU) in the Northern Italy population and to identify the sources of exposure. Ninety-five healthy subjects were selected. A spot urine sample was collected in the morning, and analyzed using GC/MS in the EI/SIM mode. Thirty-nine subjects showed urinary ETU concentrations lower than the limit of detection (LOD, 0.4 microg/g creatinine), and the remainders ETU concentrations ranging from 0.5 to 11.6 microg/g creatinine. No correlation was shown between smoke or alcohol intake and urinary ETU concentrations. Based on data on ethylene-bis-dithiocarbamate (EBDC) concentrations in food, we estimated a total EBDCs intake of 31.7-50.1 microg/day. These values are largely below the ADIs, but explain the presence of small amounts of ETU in the urine samples we have analyzed. Finally, it was estimated that the mean ETU in urine in the Italian general population is 0.6-0.8 microg/g creatinine, with a 95th percentile of 4.5-5.0 microg/g creatinine. These values can be used as reference, to compare the results of biological monitoring activities carried out on EBDCs occupationally and environmentally exposed populations.

Immunomodulatory effects of the fungicide Mancozeb in agricultural workers.

Available data suggest that ethylenebisdithiocarbamates (EBDCs) may have immunomodulatory effects. This study aimed to investigate the immunological profile of farmers exposed to Mancozeb, an EBDC fungicide, through the determination of several serum, cellular, and functional immune parameters. Twenty-six healthy subjects entered the study, 13 vineyards exposed to Mancozeb and 13 unexposed controls. Exposure was assessed through the determination of ethylentiourea (ETU) in urine. Complete and differential blood count, serum immunoglobulins, complement fractions, autoantibodies, lymphocyte subpopulations, proliferative response to mitogens, natural killer (NK) activity, and cytokine production were measured. Post-exposure samples showed ETU urine concentration significantly higher than pre-exposure and control groups. A significant increase in CD19+ cells, both percentage and absolute number, and a significant decrease in the percentage of CD25+ cells were found in post-exposure samples compared to controls. A statistically significant increase in the proliferative response to phorbol myristate acetate plus ionomycin (PMA + ionomycin) was observed in the post-exposure group compared to controls and baseline, while a significant reduction in LPS-induced TNF-alpha release in post-exposure samples was observed. Overall, our results suggest that low-level exposure to Mancozeb has slight immunomodulatory effects, and point out a method adequate to reveal immune-modifications in workers occupationally exposed to potential immunotoxic compounds, based on a whole blood assay.

Comparative (13)C and (31)P NMR studies of the ligand exchange reactions of auranofin with ergothionine, imidazolidine-2-thione and diazinane-2-thione.

The interaction of auranofin (Et(3)PAuSATg) with ergothionine (ErS), imidazolidine-2-thione (Imt) and diazinane-2-thione (Diaz) has been studied using (13)C and (31)P NMR spectroscopy. It is observed that these thiones are able to replace both Et(3)P and SATg(-) ligands simultaneously from gold(I) in auranofin forming >C [double bond] S-Au-SATg and [Et(3)P-Au-S [double bond] C<](+) type complexes. The displaced SATg(-) is oxidized to its disulfide (SATg)(2). However, some of the displaced Et(3)P is oxidized to Et(3)PO while the remaining reacts with thiones to form Et(3)P-S [double bond] C< species characterized by delta (31)P NMR of 1.0-1.5 ppm. The Et(3)PO resonance appeared in the 31P NMR spectrum, after 10 days of the addition of ErS, after 19 days of the addition of Imt and after 6 days of the addition of Diaz, to auranofin solution showing that the thiones react with auranofin very slowly.

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.

Urinary excretion of ethylenethiourea in five volunteers on a controlled diet (multicentric study).

Urinary excretion of ethylenethiourea (ETU) was monitored for 8 days in a group of five male non-smoker volunteers on a diet, the items of which were assayed for ETU and carbon sulphide. Urinary excretion of ETU reflected the consumption of wine, fruit and vegetables. Urinary ETU concentrations ranged from 0.6 to 6.7 micrograms/g creatinine. ETU concentrations in the food eaten by the volunteers were generally below the detection limit whereas in wine 8.8 micrograms/l ETU was detected. Evolution of carbon sulphide by food samples ranged from 0.03 to 0.17 mg/kg. Mean (+/- S.D.) daily intake of ETU in wine was 3.5 +/- 0.2% of the acceptable daily intake (ADI): 0.070 +/- 0.004 micrograms/kg body wt. During the 8 days of the study, an average of 48.3% of the ETU ingested in wine was excreted unmodified by the kidneys. Twenty-four hour urinary excretion of ETU was significantly correlated with daily intake of ETU (r = 0.768) and CS2 evolved by the daily food items (r = 0.414).

Degradation of ethylenethiourea (ETU) in oxic and anoxic sandy aquifers.

Ethylenethiourea is an important degradation product of ethylenebisdithiocarbamate fungicides, which are widely used in different kinds of crops. The ethylenebisdithiocarbamate group includes maneb, zineb and mancozeb. The ethylenebisdithiocarbamates are not highly toxic and degrade rapidly in the presence of moisture and oxygen, forming different compounds. One of these is the polar ethylenethiourea, which is relatively stable. Thus, this compound appears to be a potential contaminant for groundwater. Batch experiments were carried out under biotic as well as abiotic conditions to study the degradation dependence of concentration, temperature and organic matter. The decomposition of ethylenethiourea under abiotic conditions was found to be less than 5% of the degradation under biotic conditions. Further, ethylenethiourea showed to be stable over a period of 150 days at 20 degrees C in tap water as well as in batch with soil sterilized with NaN3. The degradation of ethylenethiourea depends on the concentration in the water implying first order reaction kinetics. The microbial degradation of ethylenethiourea is highly temperature dependent with aerobic Q10 between 2.9 and 4.2, and an anaerobic between 2.1 and 2.5. A minor increase in degradation rates was observed by application of nitrate and manure to the batches. The experiments show extremely complete degradation of ethylenethiourea in the presence of microbial nitrate reduction with pyrite which occurs in deeper parts of the aquifers.

Reference values of urinary ethylenethiourea in four regions of Italy (multicentric study).

The results of a study in which urinary ethylenethiourea (ETU) was assayed in the general population (167 subjects) of four Regions of Italy (Veneto, Lombardy, Piedmont and Trentino Alto Adige) are reported. The results are compared with those in a population of 97 subjects from Rovescala, a hillside wine-producing town a few kilometers from Pavia, where ethylenebisdithiocarbamates are sprayed by helicopter. It was found that an average of 24% of the populations of the four regions, taken together, had urinary ETU levels above detection limits (1.0 microgram 1(-1)) as compared to 37% of the population of Rovescala. The ranges of concentration were 0.8-8.3 micrograms 1(-1) for the four regions and 0.9-61.4 micrograms 1(-1) for Rovescala. Statistically significant variables for urinary ETU levels were smoking and wine drinking.

Ethylenebisdithiocarbamates and ethylenethiourea: possible human health hazards.

Humans are exposed to ethylenebisdithiocarbamates (EBDCs) from environmental sources. Exposure to EBDCs is chronic for workers in a variety of industries, where EBDCs are used for their properties as slimicides, vulcanization accelerators, antioxidants, and scavengers in waste-water treatment. EBDCs, and particularly the EBDC metabolite ethylenethiourea, have clearly defined, important toxic effects in various animal species, and there is reason to suspect they are carcinogenic in humans. In the absence of definitive information regarding human risk, further studies need to be done. In the interim, regular surveillance of workers with high levels of exposure to EBDCs, with specific attention to markers of thyroid and hepatic pathology, should be considered.

Gas chromatography-mass spectrometry determination of ethylenethiourea hemoglobin adducts: a possible indicator of exposure to ethylene bis dithiocarbamate pesticides.

Ethylenebisdithiocarbamates (EBDC) are an important class of fungicides used to control crop diseases and prevent mold. Ethylenethiourea (ETU), reported to be their main degradation and metabolic product in animals and man, may have teratogenic and carcinogenic properties. The feasibility of monitoring exposure to ETU on the basis of the formation of adducts to hemoglobin (Hb) was investigated. Rats given a single oral dose of ETU (from 62.5 to 500 mg/kg body wt) formed stable covalent ETU-Hb adducts. Mild acid hydrolysis of the protein regenerated ETU, allowing its detection by isotope dilution gas chromatography-mass spectrometry (GC-MS). The amount of released ETU increased with the dose. The dose-response curve fitted a linear model only between 62.5 mg/kg and 250 mg/kg. Acid-releasable ETU was also positively identified in the hemoglobin of workers exposed to Mancozeb, an EBDC formulation. In the exposed group, 40% had ETU-Hb adducts levels ranging from 0.5 to 1.42 pmol ETU/mg Hb. Such adducts might be useful for measuring EBDC exposure in humans.

[Evaluation of urinary excretion of ethylenethiourea in subjects occupationally and non-occupationally exposed to ethylenebis(dithiocarbamates)]. / Valutazione dell'escrezione urinaria di etilentiourea in soggetti professionalmente e non professionalmente esposti ad etilenbisditiocarbammati.

Ethylenebisdithiorcabamate (EBDC) fungicides are broken down metabolically and in the environment to ethylenethiourea (ETU), a suspected carcinogen. Urinary ETU was assayed in control groups and subjects occupationaly exposed to EBDC and was found to be an excellent indicator of exposure both to ETU and EBDC. Correct use of protective clothing greatly reduced exposure and urinary excretion of ETU. ETU was excreted, albeit in low concentrations, in a high percentage (91% and 30%) of subjects in both control groups, demonstrating its utility as an indicator of widespread EBDC contamination.