Experimental exposure to methylformate and its neurobehavioral effects

Objectives: The aim of the study was to investigate the acute effects of ex perimental methylformate exposure on the nervous system. Methods: In an exp osure chamber, 20 subjects were exposed to methylformate at 100 ppm [Swiss maximum allowable concentration (MAC)] for 8 h. The same number of subjects with the same ages (between 20 and 30 years), gender and education level ( university) were examined by the same procedure as a control group. The sub jects did not know if they were exposed or not. Three times (morning, noon, evening) during these 8 h, mood [Profile of Mood States (POMS)]. neurobeha vioral performance (reaction, Stroop, nonverbal learning, determination, tr acking: Wiener Test System), vision (visual acuity, contrast sensitivity, c olor sensitivity) and postural sway were tested. During an undemanding test (POMS) and a demanding performance task (determination test), pulse, elect romyography (EMG) of the forehead and of the neck were recorded. In the mor ning and evening spirometry [forced vital capacity (FVC), forced one-second expiration volume (FEV), medium expiration flow (MEF) and peak expiration flow (PEF)] and the odor perception threshold were measured. Results: In th e evening, in the exposed group, fatigue was significantly increased and th e EMG of the forehead during a demanding task showed a different developmen t during exposure. The other tests showed no significant solvent effect, bu t 16 of 43 test parameters showed a significant effect of time. Conclusions : The results of this study indicate a possible effect of methylformate exp osure on the subjective feeling of fatigue after 8h exposure at 100 ppm in young and healthy subjects, without measurable impairment of neurobehaviora l performance. We assume that a similar effect in normal work, combined wit h a heavy workload and shift work, can lead to an impairment of productivit y, and increase the risk of accidents.