Blood Lead Levels in Children Living Near Lead Smelting Zone: A Pilot Field Study

Abstract

Introduction: Children are most susceptible to lead toxicity. Exposure to lead in the environment still exists in various pockets of urban cities due to continued practices of using lead in jewellery making, paints, battery smelting and in cosmetics. Aim: To evaluate Blood Lead Level (BLL) and its association with haemoglobin, Red Blood Corpuscle (RBC) indices and bone parameters (vitamin D, parathyroid hormone, calcium, phosphorus, and Alkaline Phosphatase (ALP) in children residing near lead battery smelting units of Kolkata. Materials and Methods: This was a cross-sectional field-based study carried out by Institute of Child Health, Kolkata. A camp was organised in the month of August 2015 at a known major cluster of secondary lead smelting area ward no. 66 in the Kolkata metropolitan district. A total of 45 camp attending children were enrolled. BLL was measured using graphite furnace atomic absorption spectrometry, and association with haematological and bone parameters were evaluated. Results: Mean age of the participants was 5.6±3.3 years, and mean BLL was 3.7±1.9 μg/dL (range:1.3-8.2). About 35 children were found to have Low BLL<5 μg/dL (LBLL, 2.88±1.08) while 10 had elevated BLL≥5 μg/dL (EBLL, 6.59±0.95) (p<0.0001). Red Cell Distribution Width (RDW) was high (p=0.03) and Mean Corpuscular Volume (MCV) was low (p=0.05) in EBLL group; but there was no significant difference in haemoglobin level, compared to LBLL group. The mean vitamin D level was 15.2±8.7 ng/mL, while 23 (51%) were severely deficient without concomitant rise in parathyroid hormone (mean, 37.9±0.7 pg/mL). Calcium, phosphorous and ALP were within normal reference range. None of the bone parameters showed any correlation with BLL. Conclusion: Overall, 22% children of the cohort had elevated BLL, beyond the permissible safety limit of 5 μg/dL but within 10 µg/dL. Mildly elevated BLL relate to iron deficient hematopoiesis (increased RDW and low MCV) without any apparent affection of bone metabolism.