Hyderabad: One in every three children studying in schools located in and around industrial belts in the city silently suffer from lead poisoning and consequent anaemia.
The lead level in the blood of many schoolchildren exceeds the maximum permissible quantity by at least five micro grams. Students of schools in Cherlapalli, Hitech City, Katedan and Boduppal are the worst hit. Lead poisoning causes neurological abnormality including cognitive dysfunction.
The city-based National Institute of Nutrition collected blood samples from a number of schoolchildren and analysed them for lead poisoning. One-third of them had blood lead levels in excess of the maximum permissible levels. As against the permissible levels of 10 micro grams per decilitre, these children had reported 14.2 micro grams.
Dr B Dinesh Kumar, senior scientist attached to NIN's Food and Drug Toxicological Centre, told this correspondent that the schoolchildren showed "sub-clinical toxicity" which makes doctors difficult to diagnose the problem through clinical tests. "The students suffer silently from lead poisoning. Since lead inhibits the formation of haemoglobin, they are also diagnosed as anaemic with low iron levels in the blood," he said.
Though introduction of lead-free petrol has brought down the incidence of lead poisoning in schoolchildren living in high density traffic areas, unorganised battery sector and lead metal extraction units in and around the city continue to contribute to high blood levels in children studying in schools located in the vicinity.
"We observed high blood lead levels and reduced activity of an important enzyme called d-ALAD (Delta-aminolevulinic acid dehydratase) in children residing in heavy traffic and industrial areas. Blood lead levels but not d-ALAD activity correlated inversely with serum iron in heavy traffic and industrial children, respectively," Dr Dinesh said.