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 organ ophosphate pesticides in a group of greenhouse workers. During reentry in o rnamental plant greenhouses, five male workers were monitored far five cons ecutive 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 a ir sampling. The respiratory dose was based on a lung ventilation of 20 L/m in. 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 om ethoate, tolclofos-methyl, and fenitrothion, respectively. Multiple regress ion analysis showed that urinary alkylphosphate (nmol/24 hours) (y) was sig nificantly correlated (r = 0.716, p < 0.001) with the respiratory doses of the three active ingredients absorbed the same day (x(1)) and with the cuta neous dose absorbed the previous day (x(2)). The relationship was expressed by the equation y = 0.592x(2) + 0.117x(1) + 156.364. The doses of omethoat e absorbed by one worker were more than 45 times the acceptable daily intak e (ADI) of 1.41 nmol/kg body weight (b.w.) The ADI for fenitrothion and tol clofos-methyl (10.8 and 212.6 nmol/kg body weight, respectively) were never exceeded. High absorption by one worker underlines the importance of corre ct use of protective clothing. In this study the hands were always a source of contact with the pesticides. Greater precautions should be taken to red uce contamination (clean gloves, constant use of gloves).