Water is unsuitable even for industrial use, varsity study finds
Bangalore: The two lakes that remain in the fast developing suburb of Peenya — one of the largest industrial estates dedicated to small industries — are now so contaminated with industrial waste that they should be declared “hazard zones” with a ban on grazing, fishing and any activity that could affect human health, concludes a study by the Department of Environmental Science, Bangalore University.
In fact Karihobanahalli lake and Shivapura-Nalakadarenahalli lake are so polluted with magnesium, calcium, chlorides and other toxins that the water is “unsuitable even for industrial use”, says the research paper presented on Tuesday at a symposium on lakes organised by the Indian Institute of Science.
The study was conducted by Ph.D. scholar Aboud S. Jumbe and reader N. Nandini at the department between 2006 and 2007. Water was collected every month for a year from eight sampling points to arrive at an average figure for each pollutant. “Most of the 3,500 industries in Peenya, which produce everything from textile to electronics, discharge untreated toxic effluents without conforming to industrial norms. The natural drainage pattern takes the waste to the lakes,” Mr. Jumbe told The Hindu. The two wetlands form part of the Madhavara lake series in the Vrishabhavathi basin.
People continue to use the lakes for various purposes: to bathe, wash clothes, clean and water livestock, and irrigate the small farms that remain in Peenya. “This would increase the risk of skin and intestinal infections and also contaminate the meat and milk of animals fed here,” he said.
The ecological impact of the pollution is already visible, the study notes. The banks of the 15.5-hectare Shivapura lake are almost obliterated with industrial waste, and at the 34.8-hectare Karihobanahalli lake fish are dying; bird life in both lakes is poor. Moreover, the industrial activity has “caused a permanent destruction of replenishment channels that feed these wetlands,” the paper adds.
Chemical analysis revealed that Total Dissolved Solids (TDS) in Karihobanahalli lake and Shivapura lake were 1,838 mg/l and 1,779 mg/l respectively while the Indian Council of Medical Research (ICMR) has prescribed an upper limit of 1,500 mg/l. The magnesium level in the two lakes were 87 mg/l and 36 mg/l respectively (ICMR standards are 30 mg/l); and calcium figures were 170 mg/l and 105 mg/l respectively (ICMR standards are 75 mg/l).
The pollution has caused “irreversible environmental damage” to the lakes, which are now “extremely unsafe for any human consumption — either directly … or indirectly through animal husbandry and or crop irrigation,” the study says.