ABSTRACT
Lead toxicity causes hemotological, gastrointestinal, and neurological dysfunction in adults and children. Dust, water, paints and paint chips are still major sources of lead toxicity. Lead has been known as a highly toxic enviromental factor for a long time. In recent years several epidemiological, experimental and-clinical studies have indicated that even relatively low blood lead levels may affect the cognitive ability in young children. The following were the groups of subjects, who gave their informed consent in the study: 1-Healthy controls, fifty-four haematologically and clinically [including physical examination] male normal subjects with mean age of 45 and from different jubs served as controls, 2-Occupationally exposed subjects, fifty male painter building workers exposed to lead [mean duration of working 13 years] with a mean age of 40, were included. Subjects with any indication of coexisting iron deficiency or any abnormal findings on physical examination were excluded from the study. The standard haematological, erythrocyte delta-aminoleavulinic acid dehydratase and blood lead determinations were performed in two groups. The enzyme acitivity was significantly decreased in the occupationally exposed subjects [1304+/-146 [micro]mole L / h versus 1535+/-181, p<0.001, t=9.56] as compared to control. In occupationally exposed subjects blood lead concentrations were significantly higher than controls [1.34+/-0.6 [micro]mole/L versus 0.57+/-0.21, p<0.001, F=13.6]. In the control group there was no significant correlation between blood lead levels and logarithm of ALA-D [r=-0.21, p=0.067]]. In contrast, in exposed group a statistically significant negative correlation was noticed [r=-0.48, p<0.05]. In exposed group ferritin was significantly higher and TIBC significantly lower than in the control [76+/-23 [micro]g/L versus 58.5+/-16, p<0.01 and 47+/-15 [micro]mole/L versus 65+/-17, p<0.01 respectively]. It is generally accepted that erythrocyte ALA-D activity is the most sensitive and specific biochemical index of acute and chronic lead poisoning. Since low blood lead leveles have been associated with decline in intelligence quotient, screening programs in urban centers and occupationally exposed workers are now identifying asymptomatic individuals with elevated blood lead levels