The relation between dietary habits and urinary levels of 3-phenoxybenzoic acid, a pyrethroid metabolite.

Concerns about pesticide exposure through food consumption have increased during the past several years. Pyrethroids are applied as insecticides throughout the world. Human metabolism of pyrethroids results in urinary metabolites that are suitable for biological monitoring. The objective of our study was to investigate the relation between food consumption and urinary levels of 3-phenoxybenzoic acid (3-PBA), a general metabolite of pyrethroids, in a non-occupational exposed adult population from the IDI-IRCCS, Rome, Italy. Information on socio-demographic characteristics, smoking, diet and self-reported household pesticide exposure was collected. Urinary 3-PBA level of each subject was measured and adjusted by urinary creatinine. We found that people consuming both raw and cooked vegetables five times weekly or more had higher mean levels of 3-PBA in urine (1.03 µg/g creatinine versus 0.52 µg/g creatinine; p=0.009 and 0.99 µg/g creatinine versus 0.58 µg/g creatinine; p=0.01, respectively) than subjects consuming less than five times weekly. In a multivariate model, after adjusting for age, sex, BMI, smoking and household insecticide exposure, high intake of raw vegetables (OR: 5.31; 95%CI: 1.32-21.3) and high intake of cooked vegetables, in particular cruciferous (OR: 4.67; 95%CI: 1.07-20.5) and leafy vegetables (OR: 6.88; 95%CI: 1.50-31.7), were associated with high urine 3-PBA levels (≥0.70 µg/g creatinine). The results of this study suggest that part of the variation in pyrethrois intake is explained by vegetable intake.

Exposure to omethoate during stapling of ornamental plants in intensive cultivation tunnels: influence of environmental conditions on absorption of the pesticide.

This report describes a study of exposure to omethoate during manual operations with ornamental plants in two intensive cultivation tunnels (tunnel 8 and tunnel 5). Airborne concentrations of omethoate were in the range 1.48-5.36 nmol/m(3). Total skin contamination in the range 329.94-12,934.46 nmol/day averaged 98.1 +/- 1.1% and 99.3 +/- 0.6% of the total potential dose in tunnel 8 and tunnel 5, respectively. Estimated absorbed doses during work in tunnel 5 were much higher than the acceptable daily intake of omethoate, which is 1.41 nmol/kg b.w. This finding shows that organization of the work or the protective clothing worn in tunnel 5 did not protect the workers from exposure. Urinary excretion of alkylphosphates was significantly higher than in the general population, increasing with exposure and usually showing a peak in the urine sample collected after the work shift. Urinary alkylphosphates showed a good correlation with estimated potential doses during work in tunnel 8 and are confirmed as sensitive biological indicators of exposure to phosphoric esters. The linear regression analysis between the urinary excretion of alkylphosphate, expressed as total nmol excreted in 24 h, and total cutaneous dose allows for estimating that the fraction of omethoate absorbed through the skin during work in tunnel 8 is about 16.5%.

Evaluation of skin and respiratory doses and urinary excretion of alkylphosphates in workers exposed to dimethoate during treatment of olive trees.

This article describes a study of exposure to dimethoate during spraying of olive trees in Viterbo province in central Italy. Airborne concentrations of dimethoate were in the range 1.5 to 56.7 nmol/m(3). Total skin contamination was in the range 228.4 to 3200.7 nmol/d and averaged 96.0% +/- 3.6% of the total potential dose. Cotton garments afforded less skin protection than waterproof ones, which were in turn associated with higher skin contamination than disposable Tyvek overalls. Total potential doses and estimated absorbed doses, including their maxima, were below the acceptable daily intake of dimethoate, which is 43.6 nmol/kg body weight (b.w.). Urinary excretion of alkylphosphates was significantly higher than in the general population, increasing with exposure and usually showing a peak in the urine sample collected after treatment. Metabolite concentrations were influenced by the type of individual protection used: minimum levels were associated with the closed cabin and maximum levels with absence of any respiratory or hand protection. Urinary alkylphosphates showed a good correlation with estimated absorbed doses and are confirmed as sensitive biologic indicators of exposure to phosphoric esters.

Evaluation of respiratory and cutaneous doses and urinary excretion of alkylphosphates by workers in greenhouses treated with omethoate, fenitrothion, and tolclofos-methyl.

This research evaluated exposure pathways across work tasks for three organophosphate pesticides in a group of greenhouse workers. During reentry in ornamental plant greenhouses, five male workers were monitored for five consecutive days. Skin contamination (excluding hands) was evaluated with nine pads of filter paper placed on the skin. Hand contamination was assessed by washing with 95% ethanol. Respiratory exposure was evaluated by personal air sampling. The respiratory dose was based on a lung ventilation of 20 L/min. The doses absorbed were estimated assuming 10% skin penetration and 100% lung retention. Urinary alkylphosphates were assayed in the 24-hour urine samples of the days on which exposure was evaluated. Respiratory exposure was usually less than skin contamination, being 4.5 +/- 8.4%, 9.9 +/- 10.0%, and 49.5 +/- 26.6% (mean +/- standard deviation) of total exposure for omethoate, tolclofos-methyl, and fenitrothion, respectively. Multiple regression analysis showed that urinary alkylphosphate (nmol/24 hours) (y) was significantly correlated (r = 0.716, p < 0.001) with the respiratory doses of the three active ingredients absorbed the same day (x1) and with the cutaneous dose absorbed the previous day (x2). The relationship was expressed by the equation y = 0.592x2 + 0.117x, + 156.364. The doses of omethoate absorbed by one worker were more than 45 times the acceptable daily intake (ADI) of 1.41 nmol/kg body weight (b.w.) The ADI for fenitrothion and tolclofos-methyl (10.8 and 212.6 nmol/kg body weight, respectively) were never exceeded. High absorption by one worker underlines the importance of correct use of protective clothing. In this study the hands were always a source of contact with the pesticides. Greater precautions should be taken to reduce contamination (clean gloves, constant use of gloves).

[Biologic monitoring of occupational and non-occupational exposure to pesticides]. / Il monitoraggio biologico dell'esposizione professionale e non ad antiparassitari.

Occupationally or otherwise, much of the population is exposed to pesticides. To obtain information on exposure levels, biological monitoring is often the best choice because it provides data that reflects total exposure by all routes. Biological monitoring has been used to evaluate exposure in agricultural and industrial environments, in subjects poisoned by accidental or voluntary contact, in volunteers for pharmacokinetic studies and in the general population. This paper is based on 100 studies published on this topic and reviews exposure indices for the main classes of pesticides. Methods of sampling and conservation of samples are outlined, together with the analytical procedures used. For compounds such as organophosphate and pyrethroid insecticides, ethylenebisdithiocarbamate fungicides, and phenoxyacetic herbicides, the results of studies on the general population and groups of occupationally exposed workers are reported.

Biologic monitoring of exposure to organophosphorus pesticides in 195 Italian children.

One hundred ninety-five 6- to 7-year-old children who lived in the municipality of Siena (Tuscany, Italy), underwent biologic monitoring to evaluate urinary excretion of several alkylphosphates that are metabolites of organophosphorus pesticides. We evaluated dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP). We obtained urine samples taken in the children's schools, and each sample was accompanied by a questionnaire about lifestyle and dietary habits. We found DMP and DMTP in detectable concentrations in the greatest number of samples (96 and 94%, respectively). The DMP values were geometric mean (GM) 116.7, [geometric standard deviation (GSD) 2.5], and a range of 7.4-1,471.5 nmol/g creatinine. The corresponding DMTP values were GM 104.3 (GSD 2.8) and a range of 4.0-1,526.0 nmol/g creatinine. DMDTP, DEP, DETP, and DEDTP concentrations were GM 14.1, (GSD 3.0), and a range of 3.3-754.6 nmol/g creatinine in 34% of the children; GM 33.2, (GSD 2.4), and a range of 5.1-360.1 nmol/g creatinine in 75% of the children; GM 16.0, (GSD 2.9), and a range of 3.1-284.7 in 48% of the children; and GM 7.7, (GSD 2.1), and a range of 2.3-140.1 in 12% of the children, respectively. The significant variable for urinary excretion of these metabolites in children was pest control operations performed inside or outside the house in the preceding month; however, the presence of a vegetable garden near the house rarely emerged. The urinary excretion of alkylphosphates in children was significantly higher than in a group of the adult population resident in the same province.

Analytical method for the determination of urinary alkylphosphates in subjects occupationally exposed to organophosphorus pesticides and in the general population.

The determination of urinary alkylphosphates monitors occupational exposure to organophosphorus pesticides and insecticides. This paper describes a method for the quantitative determination of the following metabolites: O,O-dimethylphosphate (DMP), O,O-diethylphosphate (DEP), O,O-diethyldithiophosphate (DETP), O,O-dimethyldithiophosphate (DMDTP), O,O-diethyldithiophosphate (DEDTP), and O,O-dimethylthiophosphate (DMTP). The compounds are derivatized with pentafluorobenzylbromide into pentafluorobenzyl esters which are determined by gas chromatography with a capillary column of intermediate polarity and a flame photometric detector specific for phosphorus. Before the analytical gas chromatographic stage, the urinary extracts are purified on isolute SPE CN columns. The proposed method has a limit of detection of 2-3 micrograms/L at 62.5 micrograms/L and a mean recovery of the purification stage of 85.8-101.0% for all six compounds. The coefficient of variation of the analytical procedure was 7.9-11.9% for the six compounds. The low detection limits make this method suitable also for determining the six metabolites in the general population.