This story is from October 23, 2017

Kolkata's raw food is loaded with toxic lead: GSI study

From Tollygunge to Kidderpore and Gariahat to Amherst Street, every time you buy vegetables, fish, chicken or grocery from roadside markets, you are taking home dollops of heavy metal poison in the form of lead.
Kolkata's raw food is loaded with toxic lead: GSI study
A file photo of the Gariahat fish market.
KOLKATA: From Tollygunge to Kidderpore and Gariahat to Amherst Street, every time you buy vegetables, fish, chicken or grocery from roadside markets, you are taking home dollops of heavy metal poison in the form of lead. A study — released by the Geological Survey of India on Sunday — highlights the life-threatening conditions Kolkatans face from lead concentration in food, far higher than permitted limits.

Raw food items sold on the streets contain a mean lead concentration between 3.78 and 43.35 mg/kg (average 23.56 mg/kg), way higher than the threshold value of 2.5mg/kg specified by Food Safety & Standards Regulation (2011), India, the report says. About 75% of this lead contamination is contributed by atmospheric lead produced by incomplete diesel combustion, it adds.
The amount of lead concentration acceptable in the blood of children is .05 mg per litre as against .25 mg per litre in case of adults, but in both cases it is accepted that these children or adults are not exposed to excessive environmental sources of lead.
Random samples of raw food items like polished rice, red lentil (masoor dal), red spinach, chicken, fish, biscuits, spice (cumin seeds) and medicinal herb (Tulsi) were collected from 12 roadside markets covering north, south, east and west Kolkata.
Soil and vegetable samples were also collected from Dhapa, along the EM Bypass, for the study.
Street dust samples were collected from major roads in north and south Kolkata and coal samples were collected from Jharia and Ranigunj to assess the presence of atmospheric lead from the use of coal. Galena (ore of lead) samples were taken from Alwar (Rajasthan) to calculate the lead isotopic ratio of Indian lead, while rain water and diesel samples were collected from the city.

All these samples were collected to compare their lead isotopic ratios and lead concentration with that of food items sold on the city’s streets. To assess contamination in sediments and vegetables found in Dhapa, soil and vegetable samples were collected from a relatively less polluted place like Ichapur, about 30km north of Kolkata.
The maximum lead concentration was found in rice from the markets of Kidderpore, at 14.39 mg/kg. For red lentil samples, the content varied between 1.82 and 7.44 mg/kg, with the maximum found in the markets of Tollygunge. Locally-made snacks had a lead concentration range from 4.82 to 10.71 mg/kg, with the maximum found in samples from Gariahat.
The vegetable samples had a range of lead content from a low 3.28 mg/kg to a very high 145.47 mg/kg, in fish samples it ranged from 1.33 to 17.80 mg/kg, while chicken samples from a market at Garden Reach had a concentration of 9.58 mg/kg. Even spices are not free from lead and some samples of cumin (jeera) seeds collected from markets at Tollygunge had a concentration of 31.25 mg/kg.
The most alarming finding came from soil samples at Dhapa, where a maximum lead content of 800.39 mg/kg was found at Arupota. Similarly, vegetable samples collected from three Dhapa sites had an average concentration of 16.83 mg/kg. Though Ichapur is believed to be less contaminated, the soil sample had 137.75 mg/kg lead.
The GSI study also rings alarm on lead concentration in street dust. The mean concentration of lead found in 29 spots was 383.2 mg/kg with a range from 23.82 mg/kg to a very high value of 2,697.24 mg/kg at Amherst Street.
The study harps on the point that combustion of diesel significantly contributes to Kolkata’s environmental lead pollution. It was also evident from the lead isotopic signatures of coal samples from Ranigunj and Jharia that their combustion did not contribute much to Kolkata’s environmental lead pollution.
The study concludes that accumulated atmospheric lead from diesel exhausts had dominant lead isotopic fingerprints. This can be arrested by minimizing the use of diesel and by encouraging greener energy sources like LPG/CNG operated vehicles, battery operated electric cars, solar cars and increasing Metro rail network.
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