Acute effects of an organic solvent mixture on the human central nervous system.
OBJECTIVE
At workplaces, organic solvents are often used as mixtures. Nevertheless, there is limited knowledge of their acute effects on human central nervous system. Here we report the effects of a toluene-acetone mixture.


METHODS
In a parallel design, subgroups of 12 healthy men each were exposed to a mixture containing 25 ppm acetone and 250 ppm toluene or to air (control) in an exposure chamber for 4.5 hours. Concentrations corresponded to the German TLV (TRGS 403). Concentrations of toluene and acetone in venous blood were measured by headspace gas chromatography. Subjects were sedentary. The following tests were performed before and at the end of exposure: Questionnaires, simple reaction time, vigilance, quantitative analysis of EEG with open and closed eyes and during the Color Word Stress test, and visual evoked potentials (VEP).


RESULTS
Blood levels were 0.14 (+/- 0.04 SD) mg toluene/l and 5.43 (+/- 1.37 SD) mg acetone/l at the end of solvent exposure. Scores of neurotoxic and irritating symptoms were not elevated during solvent exposure. Exposed subjects performed as well as control subjects on the simple reaction time test and on the vigilance test, neither reaction time nor number of hits differed significantly. A general linear model on log transformed spectral power values showed insignificant changes in EEG. In the alpha subset2-band an average reduction to 86 % was observed in exposed as compared to non exposed subjects with closed eyes, a reduction to 88 % in the theta-band with open eyes, and a reduction to 92 % in the theta-band during the Color Word Stress test. VEP P 100 latencies and amplitudes did not change.


CONCLUSIONS
The mixture consisting of toluene and acetone did not cause any adverse acute effect. With respect to EEG data, possible subclinical effects on central nervous system cannot be excluded.
Muttray
Axel
A
Institute of Occupational, Social and Environmental Medicine, University of Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany. amuttray@uni-mainz.de
Martus
P
P
Schachtrup
S
S
Müller
E
E
Mayer-Popken
O
O
Konietzko
J
J
D000096:Acetone / Q000633:toxicity*; D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000503:physiopathology; D004338:Drug Combinations; D004569:Electroencephalography / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D008297:Male; D019055:No-Observed-Adverse-Effect Level; D011930:Reaction Time / Q000187:drug effects; D012997:Solvents / Q000633:toxicity*; D020711:Threshold Limit Values; D014050:Toluene / Q000633:toxicity*
D004338:Drug Combinations; D012997:Solvents; D000096:Acetone; D014050:Toluene