Dilution is not a solution for any kind of pollution, says T Venkatesh , professor and head of department of biochemistry and biophysics at St John's Medical College, Bangalore. He talks to Nidhi Jamwal about the grave problem of lead poisoning, especially among children, in India
How serious is the problem of lead poisoning in India?
The problem of lead poisoning is quite grave in India with 53.5 per cent of our children below the age of 12 years having their blood lead levels above 10 microgramme per deci litre (g/dL), which is the who guideline value for blood lead level. High blood lead level means that such children can have lower iq . As per the estimates of the economists, there will be a national productivity loss of Rs 600 crore annually, once these children grow up and start working.
Why are the children more susceptible to lead poisoning?
During growth and development, a child's body requires various nutrients. If lead is present in the food/environment, their body systems will not differentiate between lead and other nutrients, and absorb lead along with minerals like zinc, calcium, magnesium and iron. In adults, there is not much demand for these micronutrients, thus absorption is also less.
What are the symptoms of lead poisoning in children?
Hyperactivity, attention diversion, lack of concentration and disturbed cognitive function are some of the symptoms of lead poisoning. Blood lead level should be tested to find out if a child is suffering from lead poisoning. Once this is done, the source of lead in the environment should be identified. But not everyone can change the environment and healthy food habits are an alternative. One should avoid eating food wrapped in newspaper, as lead is used during printing. Pencils painted in different colours contain lead and chewing of pencils leads to its ingestion.
How important is supplementation of micronutrients so as to prevent lead poisoning?
If nutrients like zinc, iron and calcium are provided to a child, it prevents the absorption of lead. But all these nutrients cannot be supplied in the form of tablets to the children, as they do not like consuming tablets. So such nutrients should be provided through their daily meals, like calcium rich drinking water and normal food enriched with nutrients.
What are the various sources through which lead enters our environment?
Petrol is a major source of lead. This can be controlled by using unleaded petrol. Paints are another source of lead. We keep repainting our houses and when the old paint is removed the dust containing lead is inhaled by the children. We need to have lead free paints in the coming years. Also, we celebrate Holi, Ganesha festival and Durga Puja with chemical colours. Our waterbodies get polluted with lead when the idols are immersed in them during these festivals. This lead enters cattle when they drink the contaminated water which in turn reaches human body when they drink the milk of such cattle. Lead also gets into human body when the polluted water is used directly for cooking as is done in most rural areas.
How long does lead stay in the environment?
Forever, unless it is removed. Replacing the topsoil is a technique of removing lead, but is very expensive. India's economy might not support such a thing. But we can make efforts to reduce lead pollution. Dilution is not a solution for any kind of pollution. Solution is preventing further pollution.
How can we phase out lead from our environment?
We have started working towards that goal. George Foundation has prepared a white paper on lead pollution which has been submitted to the governments of all developing countries. The first step in this direction is to introduce unleaded petrol, which the Indian government has already done. The second step is to see that the drinking water supply does not have high lead levels. Food items should also be screened for lead levels. All this can be achieved only if public is educated about the ill effects of lead.
Do we have an effective treatment for lead poisoning?
Yes, chelation therapy for treatment of lead poisoning exists in India. Chelating agents such as edta ( ethylenediamine tetraacetic acid), penicillamines are in use for several years, though there is a need for better chelating agents
What is the National Referral Centre for Lead Poisoning (NRCLP)?
nrclp is the first national centre for lead poisoning opened in St John's Medical College at Bangalore. The main aim of the centre is to develop a uniform procedure for determination of lead poisoning in the country. Different organisations are using different standards for determining lead poisoning. In order to have uniformity, we thought of having a referral centre with an element of quality control. People all across the country can send their blood samples to be checked for lead levels. We also plan to establish a website which will educate the people about different aspects of lead poisoning. nrclp is a joint effort between the George Foundation and the St John's Medical College.
Don't you think we need to develop our own blood lead standards keeping in mind the Indian environment and body makeup?
who standards and guidelines are well established. We are not very clear about the health effects below 10 g/dL lead level. Over a period of time, we need to study the average blood lead levels in an Indian and then work out our own guidelines.
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