Crops grown in and around Bengaluru using lake water have been found to have high levels of heavy metals, way above the permissible limits, according to a recent research. The scientists conducting the study have found that consumption of these food items may prove to be fatal in the long run. Some of the crops that were sampled were spinach, tomato, paddy and beetroot among others.
All the crop samples that were collected had a higher level of chromium, cadmium and nickel that is permissible under the Indian Standards (IS). Chromium levels which according to EU (European Union) standards should be less than 0.2 mg per KG of crop and Indian standards which is 20 mg per KG of crop were high especially in crops such as knol khol, spinach, tomato, amaranthus, paddy and beetroot.
“We have found high levels of cadmium, chromium and nickel in our assessment. The heavy metals make it to the food chain when farmers use the water from these lakes to irrigate their fields and also when they use the sediments of the lake to fertilize their soil.” NB Prakash, scientist at the Department of Soil Sciences and Agricultural Chemistry at GKVK in Bengaluru, who is one one of the authors of the study told TNM.
“The accumulation is especially high in leafy vegetables as the transpiration rate is higher in leafy vegetables that allows higher quantities of metals to travel from root to stem. Also, the other reason is due to the large surface area exposed to pollution. This has been caused by years and years of pollution,” he added.
The research paper has been published in leading scientific research journal Current Science. The researchers said that there is an accumulation of heavy metals in farmland irrigated with lakes around Bengaluru such as Margondanahalli, Yele Mallapa Shetty (YMS), Hoskote Doddakere, Varthur, Byramangala and Jigani Lakes.
According to several experts, when vegetables and other produce that is contaminated with these heavy metals are consumed, they have severe consequences in the long run and could lead to many fatal diseases.
“Chromium and nickel are necessary micronutrients necessary for the body but when they are consumed in higher quantities over an extended period of time it can lead to severe health consequences. Excess chromium causes respiratory disorder. It is known to cause gastrointestinal symptoms like diarrhea, vomiting often with blood. It leads to electrolyte imbalance and even acidosis (acidity of blood and body tissues). Nickel causes respiratory disorders like chronic bronchitis, nasal sinus or even cancer,” said Seema Mukund, Nutritionist and Dietitian and Consultant at GOQii Technologies in Bengaluru.
This is not the first time research has shown that toxic metals are finding their way into crops grown in Bengaluru. In 2017 too, an expert committee formed to rejuvenate Bellandur and Varthur lakes had found that soil around the lakebed which is used for small-scale cultivation was laced with toxic metal.
Researchers had then said that even milk from cattle which grazes on these areas may also be harmful for consumption.