Monoterpene and wood dust exposures: work-related symptoms among Finnish sawmill workers

Monoterpenes and wood dust are released into the work environment during sawing of fresh wood. Symptoms related to exposure to monoterpenes and wood dust include irritation of the eyes, mucous membrane, and skin.

We studied 22 sawhouse workers who process pine and spruce in 1997-99. Exposure to monoterpenes was assessed by determining monoterpenes in air and verbenols in urine by gas chromatography using flame ionization detection. Wood dust was determined gravimetrically. A questionnaire was used to evaluate work-related subjective symptoms.

Exposures to monoterpenes (geometric mean, GM) among sawhouse workers were 61-138 mg/m(3) and 2.0-13 mg/m(3) during processing of pine and spruce, respectively. Urinary verbenol correlated well with worker exposure to the alpha-pinene fraction of monoterpenes. The inhalable dust concentration in the breathing zone was 0.5- 2.2 mg/m(3) during pine processing and 0.4-1.9 mg/m(3) during spruce processing. The prevalence of symptoms, in the eyes or respiratory tract, was high during both seasons and in connection with either tree species.

The highest monoterpene concentration (GM), in the breathing zone, measured during processing of pine, was less than one-fourth of the Finnish occupational exposure limit (OEL, 570 mg/m(3)). Verbenol concentrations in postshift urine samples reflected accurately the exposure to monoterpenes. The concentrations of inhalable dust (GM) were less than one-half the Finnish OEL (5 mg/m(3)). No significant differences in dust exposure were observed among tree species processed. Work-related symptoms appeared to correlate with monoterpene exposure during processing of pine and with wood dust exposure during processing of spruce.