A Study on the Lead Exposure of Workers in Secondary Smelting and Litharge Making Industries

Chae, Je Myung; Lee, Gap Soo; Lee, Sung Soo; Ahn, Kyu Dong; Lee, Byung Kook

Abstract

Two hundred and six male lead workers (86 lead workers from secondary smelting industries and 120 lead workers from litharge making industries) and 212 office workers who were not exposed to lead occupationally were studied to investigate the effect of lead on the health of lead workers in high risk operation to lead. Blood lead (PbB), zinc protoporphyrin in whole blood (ZPP), delta-aminolevulinic acid in urine (ALAU), Hematocrit (Hct) and hemoglobin (Hb) were selected as an index of lead exposure. Questionnaires of 15 lead related symptoms were provided to all study subject and filled up by themselves and reconfirmed the symptom answers by interviewing medical doctor. While the mean value of PbB, ZPP and ALAU of lead workers in secondary smelting industries were 62.7+/-14.6 microgram/dl, 103.1+/-60.5 microgram/dl and 7.4+/-10.3 mg/liter, those of lead workers in litharge making industries were 58.8+/-14.1 microgram/dl, 74.2+/-45.2 microgram/dl and 5.3+/- 7.9 mg/liter respectively, and there were statistically significant difference of mean values between two groups. Simple linear regression analysis of PBB on ZPP and ALAU shoved the steeper slope in secondary smelting industries than litharge making industries. Higher symptom prevalence rates of lead exposed group were observed in lead colic related symptom (S4) and neuromuscular symptoms compared with non-exposed workers. The prevalence of neuromuscular symptoms only showed dose-response relationship by the increase of PBB and ZPP. But more statistical significances were observed in neuromuscular symptoms by the increase of PBB than ZPP. On stepwise multiple regression using total symptom score as a dependent variable and PBB, ZPP, ALAU, Hct, Hb, age and work duration as a independent variables only ZPP and age contributed to the lead related symptoms.