Bangalore lakes are toxic

Bangalore lakes are toxic


Navya P K
First Published : 31 Jan 2009 11:00:00 AM IST
Last Updated : 31 Jan 2009 12:38:58 PM IST

BANGALORE: It’s a fact known for a long time, that lakes in Garden City are dumping yards for waste. Of the 15 lakes in the city, water samples of which were analysed by KSPCB in July- November 2008, 10 were found to belong to class D on a rating scale of A-E, with A representing good quality water and E representing waste water.

Being classified under D category meant that the total coliform and faecal coliform levels in these lakes are extremely high. “Most of the lakes here have high levels of coliform as sewage gets mixed with lake water.

Coliform and other bacteria can cause diseases such as diarrhoea, typhoid and cholera,” says Dr Aruna Rudrappa, joint director, Public Health Institute.

Even if residents in the area do not use the water directly, the water bodies nearby get contaminated.

Of the 15 lakes, two are found to exceed the permissible levels (PL) of heavy metals. The PL for lead is 0.05 milligram/litre. Arakere and Kempambudi Lakes are found to have a lead content of 0.75 mg/l and 0.132 mg/l respectively. Arakere Lake also has 2.05 mg/l of copper while the PL is 1.5 mg/l. Kempambudi Lake had 1.228 mg/l of iron while the PL is 1 mg/l as per standards.

The high lead content can cause liver, kidney and gastro-intestinal damages and affect fertility, while high copper levels can cause hypertension and sporadic fever.

“In addition to groundwater contamination, aquaculture and farming get affected. Farm produce and products from animals that consume lake water may contain toxic materials. In many areas, residents use lake water for washing clothes and bathing animals.

Cases of infections, allergies and diarrhoea are common,” Heblikar explained.

Nayandahalli Lake, Kempambudi Lake, Madiwala Lake, Arakere Lake, Kalena Agrahara Lake, Puttenahalli Lake, Parappana Agrahara Lake, Iblur Lake, Haralakunte Lake and Singasandra Lake are the ones classified under D.

However, reduced levels of Dissolved Oxygen (DO) can make lakes deathbeds for aquatic species. In Nayandahalli Lake and Madiwala Lake, the DO is 0 and 2 mg/l respectively, while the minimum required level of DO is 4 mg/l.

The Lalbagh and Yediyur Lakes are categorised under class A. Hulimavu, Begur and Gottigere Lakes fall under Class B.