Chemical analysis of samples collected as a part of groundwater monitoring, carried out by the Central Ground Water Board (CGWB), has only validated the worst fears of residents of Mandur in Bengaluru South taluk, which was the destination for the city’s garbage for years.
According to the analysis, the nitrate value in the samples collected in Mandur is as high as 244 mg/l against the permissible levels of 45 mg/l. This apart, samples collected from this village also displayed a total hardness value of 764 mg/l against the permissible limit of 600 mg/l.
K.M. Najeeb, former regional director of the CGWB, Karnataka, attributed this to indiscriminate dumping of un-segregated waste and leaking sewer lines. “Nitrate contamination has been usually found near industries, areas surrounding corroded sewer lines, polluted lakes, and market areas where garbage decays and percolates into the ground,” he told The Hindu .
Fluoride and radon tooIn 2013, the CGWB had found fluoride and radon gas above permissible levels in the city’s groundwater. “While radon contamination was found in Bengaluru North and Bengaluru South taluks and parts of Anekal taluk, fluoride content was as high as 5.54 mg/l in parts of Bellandur. The permissible limit for human consumption is 1.5 mg/l,” he said.
Although radon contamination will not have any health impact unless it is inhaled, he warned that there are chances of the vapours being inhaled if a person is having a shower.
Another CGWB official pointed out that groundwater in industrial areas, such as Peenya, K.R. Puram and Bommanahalli, has always shown alarming quantities of heavy metals, including carcinogenic chromium. “The groundwater in old Bengaluru areas has been found to be contaminated with sewage and chemicals such as nitrate,” the official said.
