Abstract

This study intended to obtain an useful information on the prevalence of subjective symptoms, and to clarify the interrelationships between blood lead and lead related symptoms in low level lead exposure. The 93 male workers exposed to lead and 56 male nonexposed workers were examined for their blood lead (PBB), Zinc-protoporphy (ZPP), hemoglobin (HB) and personal history, and completed 15 questionnaires related to symptoms of lead absorption; also measured lead concentration in air (PBA) in the workplace. The results obtained were as follow; 1. The means of blood lead (PBB), blood ZPP and hemoglobin (HB) among workers exposed to lead were 26.1+/-8.8 microgram/dl, 28.3+/-26.0 microgram/dl and 16.2+/-1.2g/dl; whereas those of nonexposed workers were 18.7+/-5.1 microgram/dl, 20.6+/-8.7 microgram/dl and 17.3+/-1.1g/dl. The means of above three indicies between two groups showed significant difference statistically (p<0.05). 2. The means of blood lead (PBB), blood ZPP and hemoglobin of workers exposed to different lead concentration in air were as follows; When it was below 25 microgram/m3 , the indices were 24.7+/-79, 26.1+/-26.8 microgram/dl and 16.4+/-1.1 g/dl respectively; These indices were 27.1+/-8.5, 23.9+/-10.92 /dl and 16.2+/-1.3 g/dl when the lead concentration in air was 25~50 microgram/m3; and they were 3.4+/-9.3, 42.3+/-31.3 microgram/dl and 15.5+/-1.2 g/dl when the concentration of lead was above 50 microgram/m3. Although there were statistical difference in blood lead and hemoglobin among three different lead concentration in air, there was no statistical difference of blood ZPP among the three groups with different exposure levels (p>0.05). 3. The most frequently by complained symptom was "Generalized weakness and fatigue", and fewest symptom was "Intermittent pains in abdomen". 4. Only two symptoms out of fifteen symptoms checked by themselves revealed significant difference between exposed and nonexposed groups. These were "Intermittent pains of abdomen" and "Joint pain or arthralgia" (p<0.05). No positive correlation was found between the levels of blood lead and symptom groups categorized as gastrointestinal, neuromuscular and constitutional symptoms. 5. Blood lead (r=0.3995) and ZPP (r=0.2837) showed statistically significant correlation with mean lead concentration in air, whereas correlations were not demonstrated between blood lead and lead related symptoms or blood ZPP and lead related symptoms. 6. Blood lead (PBB) and ZPP showed association (r=0.2466) and the equation PBB=23.75+0.0842 ZPP was derived. 7. On stepwise multiple regression, using blood lead level as a dependent variable and ZPP, hemoglobin (HB), age, work duration (WD) and symptom prevalence as a independent variables, only ZPP significantly contributed a lot to blood lead level. 8. While the ZPP measurement was found to be a good indicator in evaluating health effect of lead absorption in low level lead exposure, lead related symptoms were not sensitive enough to evaluate of lead absorption in low level exposure.

• Keywords: blood leadZPPlead related symptomslow level lead exposure