Tremor in workers with low exposure to metallic mercury

In a fluorescent lamp production factory, a newly developed lightweight balance-tremormeter was used to measure postural tremor of the finger in 21 workers (ages 28 to 61) exposed for 0.5-19 yr to metallic mercury. In addition, tremor was measured in an indirect way by means of a "hole-tremormeter." The excretion of mercury in urine was 9-53 (average 20) mumol/mol creatinine. With increasing mercury excretion, the following parameters increased: the acceleration of the tremor, the contribution of the neuromuscular component (8-12 Hz) to the power spectrum of the acceleration, the width of the power-spectrum and the score on the hole-tremormeter. The study indicates that exposure to metallic mercury below the current TLV (50 micrograms/m3) may increase the tremor of the finger.