Objective   To investigate the alteration of trace elements, SOD, LPO-MDA, systemic iron metabolism, an occupational epidemiological survey was designed.

  Methods   To measure serum LPO-MDA, iron, manganese, copper, lead, zinc, ferritin, transferrin, transferrin receptors and blood SOD in both population exposed to manganese and controls.

  Results   (1) The activity of SOD decreased and the level of LPO-MDA increased.(2)The transferrin concentrations in serum were significantly higher(about 1.19 fold, P < 0.05)in welders than in controls.In contrast, transferrin receptors were significantly lower(about 1.34 fold)in welders than controls(P < 0.01).There was no difference in serum ferritin between the two groups (P > 0.05).(3)Mn and Fe concentrations in welders were higher than those in control subjects.However, the concentrations of serum Zn and Pb were lower than those of control subjects.

  Conclusion   There was the alteration of SOD and LPO-MDA in welders.There was increase of transferrin and decrease of transferrin receptors, indicating alterations in peripheral iron metabolism in manganese-exposed workers.The welding fume among career welders disturbed the serum homeostasis of trace elements.