Acute symptoms during non-inhalation exposure to combinations of toluene, trichloroethylene, and n-hexane.

OBJECTIVE

To study the acute effect of exposure to a mixture of three commonly used solvents in humans using a route of exposure not involving the nose and lungs, in this case a gastrointestinal application.

METHODS

In a 2(3)-factorial experiment eight healthy male volunteers were exposed to the eight combinations of toluene (1. 5 and 4 mg. min(-1)) trichloroethylene (1.5 and 4 mg. min(-1)), and n-hexane (0.3 and 1.0 mg. min(-1)) for 60 min given into the stomach via a feeding tube. The body burden was measured by the exhaled solvent concentrations and the urinary excretion of metabolites during and after exposure. The subjective ratings of tiredness, sleepiness, headache, nausea, feeling of intoxication, and dizziness were estimated by continuous linear analogue rating scales before and 30, 90, and 240 min after the start of exposure.

RESULTS

Concentrations of the three solvents in the end exhaled air varied between 0 and 46 mg. min(-3). The ratings of symptoms were generally low and there was no difference between the high and low doses. Neither was there any correlation between the concentration of solvents in the exhaled air and the ratings.

CONCLUSIONS

The study show no effects at levels in end exhaled air of mixtures of solvents which in inhalation studies have given signs of a possible neurotoxic effect. The lack of symptoms using this alternative route supports the hypothesis that "neurotoxic" symptoms in relation to exposure to very low air concentrations of solvents are mainly indirect, mediated by irritation or smell.