Biochemical aspects of lead exposure and toxicity in spray painters of Western Maharashtra (India)

The present study was undertaken to assess biochemical, hematological and antioxidant status of possible lead exposed spray painters of Western Maharashtra (India). Thirty spray painters (SP) and thirty five normal healthy subjects were taken (age 20-40 years) from the Western Maharashtra for this study. Venous blood samples and random urine samples were collected from both the groups. The blood Pb level of SP group (N = 30) was found to be in the range of 7.5 to 45.7 microgram/dL (Mean ± SD, 22.32 ± 8.87 microgram/dL) whereas that of the unexposed control group (n= 35) was in the range of 2.8-22.0 microgram/dL (Mean ± SD, 12.52 ± 4.08microgram/dL). The blood lead level (Pb-B) and urinary lead level (Pb-U) were significantly increased in SP group as compared to control group. Though activated and non-activated erythrocyte-ALAD activities in SP group did not show any significant change as compared to the control group, the ratio of activated/non-activated erythrocyte ALAD activities in SP group showed a significant increase (p<0.001). Erythrocyte zinc protoporphyrin (ZPP) level was not altered in SP group as compared to control group. A significant elevation of urinary d-aminolevulinic acid (ALA-U) and porphobilinogen (PBG-U) were observed in the SP group. A positive correlation (r = 0.45, p< 0.001) between Pb-B and ALA-U was found in the SP group, but no significant correlation was observed in the control group. Hematological parameters were not altered significantly in the SP group as compared to control group except a significant increase (p<0.05) in mean corpuscular hemoglobin concentration (MCHC). The serum malondialdehyde (MDA) content was significantly increased (p<0.001) and the activities of antioxidant enzymes such as erythrocyte superoxide dismutase (SOD) (p< 0.001) and erythrocyte catalase (p< 0.05) were significantly reduced in the SP group as compared to control group. Therefore the study clearly indicates an adverse effect of lead on heme biosynthesis and imbalance of prooxidant/antioxidant status in spray painters from Western Maharashtra (India) associated with increase lipid peroxidation in association with decreased erythrocyte SOD and catalase activities.