Researchers have found that popular vegetables like tomato, brinjal, Amaranthus (thotakura) and spinach (palak) are contaminated by heavy metals with the potential to accumulate in different body parts

Syed Akbar
Hyderabad: Researchers have found that popular vegetables like
tomato, brinjal, Amaranthus (thotakura) and spinach (palak) are
contaminated by heavy metals with the potential to accumulate in
different body parts.

Vegetables grown in rural areas are relatively less contaminated than
those cultivated in urban and industrial localities. The heavy metals
found in vegetables included zinc, copper, lead, nickel, chromium,
cobalt, iron and manganese.

“Heavy metal contamination of vegetables cannot be underestimated, as
these foodstuffs are important components of human diet. Intake of
vegetables contaminated with heavy metals may pose a risk to the human
health because of their non-biodegradable nature, long biological
half-lives and their potential to accumulate in different body parts.
Therefore, health risk assessment gives information about the threat
posed by heavy metals in vegetables,” said Mr Penmethsa Kiran Kumar
from the department of chemistry, Government College for Women,
Srikakulam.

Mr Kiran Kumar and his team collected tomatoes, Amaranthus, spinach
and brinjal from fields and markets and analysed them for heavy metal
contamination. The contamination for various metals ranged from 0.067
to 1.03 mg per kg in case of zinc, 0.030 to 0.70 copper, 0.012 to
0.048 lead, 0.008 to 0.03 (nickel), 0.16 to 0.45 chromium, 0.0003 to
0.0011 cobalt, 0.21 to 0.51 iron and 0.03 to 0.09 mg/kg for manganese.

“Our study highlights that both children and adults consuming
vegetables ingest significant amount of these metals. Though the
values of the metals were well below the recommended tolerable levels
proposed by the Joint FAO/WHO Expert Committee on food additives,
regular monitoring of levels of these metals in vegetables is
essential to prevent excessive build up in the food chain,” he pointed
out.

Heavy metals exhibit neurotoxic (damage to nervous system), mutagenic
(causing mutations), teratogenic (birth defects) and carcinogenic
(causing cancers) effects even at very low concentrations. Their
exposure may lead to several diseases like cardiovascular, tubular
dysfunction in kidneys, immunological disorders and nervous disorders
due to metal toxicity.

Mr Kiran Kumar said contamination of vegetables with heavy metal might
be due to irrigation with contaminated water, the addition of
fertilizers, metal-based pesticides, sewage sludge, organic manures
and composts, industrial emissions, vehicular emissions,
transportation, the harvesting process, storage and /or at point of
sale. As plants acquire the necessary nutrients such as nitrogen,
phosphorous and potassium, they also take in and accumulate metals
such as lead and cadmium. The heavy metals are taken up by the roots
or foliage of the plant.