Thursday, April 27, 2006

Lake Water Used For Growing Crops High In Metals

Vegetables can land you in soup!
Lake Water Used For Growing Crops High In Metals
The Times of India

Bangalore: Want to relish that lipsmacking brinjal curry? Or savour tomato soup? Think twice. You may be eating ‘poison’. For, around 70% of toxic metals dumped into the city’s sewerage are making way into your system, through the veggies.

The latest study by the Lake Development Authority (LDA) on the metal content in three water bodies — Byramangala, Bellandur Lake and Varthur tank — that serve agricultural land around the city is shocking. In Bellandur Lake, the lead content is 1,590 times more than the permissible limits and mercury 200 times. In Varthur tank, the nitrate level is almost six times the normal levels.

The metal-loaded content of these water bodies, into which 1,000 million litres of city sewage is emptied every day, has been declared “not suitable for continuous application to land” by the LDA. Yet, water from these lakes is being used liberally by the farmers along this belt.

“Since the sewage water is rich in nitrates and phosphates, farmers use it for agriculture, horticulture and vegetable crops. These are distributed all around the local and the urban market,’’ said a scientist from the Soil Sciences and Agricultural Chemistry department at Gandhi Krishi Vigyan Kendra (GKVK).

A GKVK study confirms the presence of toxic metals in beans, ladies finger, brinjal, tomatoes, sugarcane and maize. The landuse analysis, using multidate satellite images and preliminary probe, reveals that land on either side of Byramangla Lake uses contaminated water to cultivate crops.

Digest this: Water, soil, air carry toxin

Bangalore: You reap as you sow — this idiom has proved true in the case of vegetables grown on land irrigated by three main lakes in the city, Byramangala, Bellandur Lake and Varthur Tank. With the crop being fed with metal-heavy water — they have been rendered unhealthy for consumption.

Plants require 16 nutrients (elements) to grow. Thirteen of these are drawn by plants when they dissolve in soil — Nitrogen, phosphate, potassium, calcium, magnesium, sulphur, zinc, iron, copper, manganese, boron, molybdenum, chlorine. Carbon, hydrogen and oxygen are taken from the atmosphere and water, explained a scientist from GKVK.

Nutrients like zinc, copper, manganese and boron, termed as ‘micro nutrients’, are required by the soil only in “alarmingly low levels, that too depending on the soil type’’. Since heavy metals like zinc, mercury and lead among others are also soluble in water, they too get absorbed by plants, leading to high levels of metal in the vegetables.

In January, The Times of India has reported that the increase in pollution level in Bellandur lake had led to skin and respiratory allergies among residents living in the vicinity. But the Lake Development Authority has not yet taken any remedial measures.

The report had revealed that an ill-conceived cleaning up project at a cost of Rs 1.82 cr started in 2003 had gone waste. The LDA realised it only in 2005. Admitting that they had given up hopes of improving the condition of the three water bodies, an LDA official said, “We cannot do much in the issue as the lakes are almost 100 per cent polluted.’’

It’s slow poisoning

“Excess amount of lead is known to act as a ‘slow poison’ in the body, as it causes neuro-toxicity. It causes degeneration of nerves in the brain and kidneys. Presence of nickel causes allergy, and the presence of any metal in excess is certainly harmful,’’ said director of Manipal Institute of Neurological Disorders Dr N K Venkataramana.

Here are some statistics on the use of land for vegetable cultivation
Total land: 37578 hectares Urban area: 8744 hectares Forest area: 1551 hectares Cultivated area irrigated with polluted water: 1347 hectares Cultivated area irrigated with nonpolluted water: 645 hectares


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