In order to evaluate the degree of manganese exposure and its health hazards effect on welders in manufacturing industry.

The author measured airborne, blood and urine concentrations of manganese and blood chemistry, and also observed clinical symptoms and signs on 60 welders for case an.d 60 non-welders for control working in manufacturing industry by age maching method.

The geometric means of blood and urine concentrations of manganese were 1.13 +/- 1.38 microgram /dI and 2.52 +/- 1.37 microgram /I for Welders group, 1.09 +/- 1.68 microgram /dl and 1.86 +/- 1.34 microgram / I for Non-welders group. Airborne concentration of manganese was 0. 15 +/- 1.66 mg/m3 for exposured group, and the urinary mean concentration of manganese was statistically significant difference between exposured and non-welders group (P < 0.05). Clinical signs in welders group were palmomentle reflex (23.3%), tremor (20.0%) and grabellar sign (5.0%). Symptoms in welders group were fatigue (66.7%), amnesia (66.7%), excessive sweating (51.7%), nervousness (51.7%), general weakness (48. 3%) and arthralgia (46.7%) and so on, and there was statistically significant difference compared to non-welders group (P<0.05). Manganese exposure effects on blood chemistry were not observed. There were statistically significant correlation between manganese concentration in blood and urine (r=0. 269), airborne and urine (r=0. 601) and airborne and blood (r=0. 268).

The author suggest that further studies are followed to evaluate the health status of welders whose blood and urine manganese concentrations were below normal reference level, and to establish the questionnaire and the diagnostic tools for early detecting the chronic manganese poisioning on welders.