Kolkata, Oct 22 (PTI) Raw food items sold in most citymarkets have Lead concentration far above the permissiblelimit and can permanently damage key human organs, a surveyconducted by the Geological Survey of India (GSI) has found.
Samples of raw food items like polished rice, redlentil (masoor dal), red spinach, chicken, fish (withoutscales), biscuits, spice (cumin seeds) and a common medicinalherb (Holy Basil or Tulsi), collected from 12 markets in thecity showed a mean Lead (Pb) concentration between 3.78 and43.35 mg/kg (average 23.56 mg/kg).
"The mean Lead concentration found in the raw foodmaterials is very high compared to the threshold value of2.5mg/kg specified by Food Safety & Standards Regulation(2011), India," senior scientist of the GSI, Avijit Das, whoheaded the group conducting the two-year study, said today.
As per the American and European standards, thecurrent reference range for acceptable bloodLead-concentration in a healthy human being, without excessiveexposure to environmental sources of Lead, is less than 0.05mg/L for children whereas it is less than 0.25 mg/L foradults.
Prolonged exposure of lead, which is a highly toxicelement, to humans can cause permanent damage to the kidneys,liver and hematologic systems.
Children are more at risk because lead exposure canreverse their brain growth and cause irreversible damage totheir overall well being.
The study, conducted by leading scientists of the GSI,also found that about 75 per cent of the Lead contamination inthe food items sold in Kolkata markets, were contributed byatmospheric Lead, mainly produced by the combustion of diesel.
Apart from collecting soil and vegetable samples fromDhapa ground, alongside the EM Bypass, for the study of Leadcontamination, the scientists had also collected street dustsamples from major roads of the northern and southern parts ofthe city for the study.
"Coal samples were collected from Jharia and Ranigunjto assess the presence of atmospheric lead from the use ofcoal while Galena (ore of Lead) samples from Alwar (Rajasthan)were brought to calculate the Lead Isotopic Ratio (LIR) ofIndian lead," Das said adding, rain water and diesel sampleswere collected from city markets for the study.
"All these samples were collected to compare their LIRand lead concentration with that of the raw food items sold inKolkata markets," he added.
To compare the level of contamination in sediments andvegetables found in Dhapa, soil and vegetable samples werecollected from a relatively less polluted Ichapur (ControlSite) in North 24 Parganas district.
The maximum Lead concentration in rice was 14.39mg/kgfound in the samples collected from a market in Kidderpore inthe western part of the city, the study said.
"The Lead concentration in red lentil samplescollected from markets in Tollygunge in south Kolkata wasfound to be between 1.82 and 7.44 mg/kg," Das said.
Samples of vegetables sold in different markets alsorevealed a Lead concentration ranging from a low of 3.28 mg/kgto a very high value of 145.47 mg/kg while fish had a range of1.33 to 17.80 mg/kg, he said.
Chicken collected from a market at Garden Reach in thecity's port area showed a Lead concentration of 9.58 mg/kg.
"The whole cumin seeds samples collected from a marketin Tollygunge area had a Lead-concentration value of 31.25mg/kg. Among the herb (tulsi) samples, the range of leadconcentration was from 8.92 to 33.27 mg/kg," Das said.
Vegetable samples from the three different sites inDhapa showed an average Lead concentration of 16.83 mg/kg withthe Bainchtola sample bearing the minimum with 13.24 mg/kg.
"The less contaminated soil and vegetable samplescollected from Ichapur had a total Lead concentration valueof 137.75 mg/kg for soil sample and 5.17 mg/kg respectively,"it revealed.
The average Lead concentration in soil samplescollected from the three sites at Dhapa was 475.85 mg/kg withthe minimum value of 197.09 mg/kg at Bainchtola and a maximumof 800.39 mg/kg at Arupota.
The Lead concentration in locally made snacks werefound to be in the range of 4.82 to 10.71 mg/kg with themaximum found in the sample collected from Gariahat in southKolkata.
Das said the survey also found that the Leadconcentration in street dust of the city was worrisome.
"The mean concentration of Lead found in the 29 sitesof the city was 383.2 mg/kg with a range from 23.82 mg/kg to avery high value of 2,697.24 mg/kg at Amherst Street in northKolkata," he said.
On ways to tackle the Lead contamination, Das said itcould be done by minimising the use of diesel and by urgingpeople to use green energy in vehicles.
"We must encourage the mass traffic movements bygreener energy sources like LPG/CNG operated vehicles, batteryoperated electric cars, solar cars, increasing metro railnetwork," Das said.
The study was published in the peer reviewedInternational journals of "Environmental Science andTechnology (2017) (online publication)" and "EnvironmentalScience and Pollution Research (2016)". PTI SCHJM.
This is unedited, unformatted feed from the Press Trust of India wire.