sulabh swatchh bharat

Thursday, 22-November-2018


The lead concentration in the city’s food has shot through the roof: GSI Study

Snacks in Gariahat are mouth-watering; variety of fish in Ballygunj is indeed, awesome; the red lentil (mosur dal) in Tollygunj is too inviting to be ignored; chopped chicken in Garden Reach is jaw-dropping; eateries around the Sealdah station are dirt cheap....the food fest for the Bongs and wanderers in Kolkata is simply irresistible. So is the level of poison in them.
Believe it or not, the lead concentration in the city’s food has pierced through the roof. And, with each passing day, the situation is turning murkier; at least, that’s what the scientists at the Geological Survey of India(GSI) have found. A new survey recently conducted by the GSI  has found that the raw foods and vegetables sold in most of the markets that have sprung up on places and sidewalks in close proximity to the streets have lead concentrations way above the permissible limits. This might sound contrary to the popular belief that consumption of raw food, especially vegetables is good for one’s health. But the scientists at GSI feel otherwise; according to these group of scientists, raw foods and vegetables are actually harmful to  health and can permanently damage key human organs.
 The GSI scientists who had collected samples of raw food items like polished rice, red lentil (masoor dal), red spinach, chicken, fish (without scales), biscuits, spice ( (cumin seeds) and a common medicinal herb (Holy Basil or Tulsi) from 12 markets in the city found a mean Lead (Pb) concentration between 3.78 and 43.35 mg/kg  against a normal average of 23.56 mg/kg.
“The mean Lead concentration found in the raw food materials is very high compared to the threshold value of 2.5mg/kg specified by Food Safety & Standards Regulation (2011), India,” senior scientist of the GSI, Avijit Das, who headed the group conducting the two-year study, said.
As per the American and European standards, the current reference range for acceptable blood Lead-concentration in a healthy human being, without excessive exposure to environmental sources of Lead, is less than 0.05 mg/L for children while it is less than 0.25 mg/L for adults. Since lead is a highly toxic element, prolonged exposure to lead, to humans can cause permanent damage to the kidneys, liver and hematologic systems. And what is most important for parents to take note of is that children are more at risk because lead exposure can reverse their brain growth and cause irreversible damage to their overall well being.
The crucial point that the GSI study has highlighted (keeping in mind the Kolkatans’  reputed penchant for street foods)  is that about 75 per cent of the Lead contamination in the food items sold in Kolkata markets has been contributed by atmospheric Lead, mainly produced by the combustion of diesel. Apart from collecting soil and vegetable samples from Dhapa ground, alongside the EM Bypass, for the study of Lead contamination, the scientists had also collected street dust samples from major streets and roads of the northern and southern parts of the city.
“Coal samples were collected from Jharia and Ranigunj to assess the presence of atmospheric lead from the use of coal while Galena (ore of Lead) samples from Alwar (Rajasthan) were brought to calculate the Lead Isotopic Ratio (LIR) of Indian lead,” Das said. This apart, rainwater and diesel samples have been collected from city markets for the study. “All these samples have been collected to compare their LIR and lead concentration with that of the raw food items sold in Kolkata markets,” he added. To compare the level of contamination in sediments and vegetables found in Dhapa, soil and vegetable samples have been collected from a relatively less polluted Ichapur (Control Site) in North 24 Parganas district.
Elaborating on the findings, Mr Das said that the maximum Lead concentration in rice was 14.39mg/kg found in the samples collected from a market in Kidderpore in the western part of the city. “The Lead concentration in red lentil samples collected from markets in Tollygunge in south Kolkata was found to be between 1.82 and 7.44 mg/kg, which is quite alarming.”
As for vegetables sold in different markets, the study revealed a Lead concentration ranging from a low of 3.28 mg/kg to a very high value of 145.47 mg/kg while fish had a range of 1.33 to 17.80 mg/kg. Interestingly, there’s a shocking news for chicken lovers; samples of chicken collected from a market at Garden Reach in the city’s port area showed a Lead concentration of 9.58 mg/kg. “ This is simply unbelievable,” the GSI scientist stated. The entire cumin seeds samples collected from a market in Tollygunge area had a Lead-concentration value of 31.25 mg/kg. Among the herb (tulsi) samples, the range of lead concentration was from 8.92 to 33.27 mg/kg”. Samples of vegetables from the three different sites in Dhapa showed an average Lead concentration of 16.83 mg/kg with the Bainchtola sample bearing the minimum with 13.24 mg/kg.The less contaminated soil and vegetable samples collected from Ichapur had a total Lead concentration value of 137.75 mg/kg for soil sample and 5.17 mg/kg respectively. The average Lead concentration in soil samples collected from the three sites at Dhapa was 475.85 mg/kg with the minimum value of 197.09 mg/kg at Bainchtola and a maximum of 800.39 mg/kg at Arupota.
The GSI scientists who had already shared their findings with the senior health officials of the Kolkata Municipal Corporation and the West Bengal government felt that there is an urgent need for launching a sustained campaign to drive home the message how lead poisoning has reached an alarming level in the city and neighbouring areas. People’s fascination to have a go at the snacks on the street requires to be contained if they know that the Lead concentration in locally made snacks have been found to be high.