[Studies on semen quality in workers exposed to manganese and electric welding]

Three hundred and ten workers were selected to study the effects of manganese and electric welding on male reproductive function, with 211 occupationally exposed to manganess and electric welding fume and 99 controls. Concentrations of manganese and welding fume in the air of the workplace were 0.14-5.5 mg/m3 and 6.5-82.3 mg/m3, respectively. Semen concentrations of manganese, copper, chromium, nickel, and iron in workers employed in electric welding were significantly higher than those in controls. Time from ejaculation to liquefaction of semen in exposed workers was longer than that in controls, and volume of semen, sperm count, viable sperm count and percentage were significantly lower in the exposed workers than in the controls. Stepwise regression analysis suggests a direct toxic effect of manganese on sperm production.