The Hindu 10.06.2010
Quality of groundwater deteriorates?
Sumit Bhattacharjee
| Traces of heavy metals in certain areas a cause for concern |
Women fetching drinking water from a pipeline located close to a leaking sewer line in the Old Town area in Visakhapatnam on Wednesday.
VISAKHAPATNAM: Some 96 per cent of total water available on the globe is salt water. About 1 per cent to 1.5 per cent is covered by ice caps. While 0.5 per cent caters to the salt lakes, the remaining portion is surface water and sub-surface or ground water. It is estimated that only 1 per cent of water is readily available for human consumption at the moment.
Given the scenario, this city finds itself in a precarious situation, with the sea on one side and hills on the other three sides. Nestled in a natural bowl, and thanks to the industrial development, the groundwater scenario is alarming.
According to P.V.V. Prasada Rao, a professor in the Department of Environment Sciences, Andhra University, the groundwater in certain areas like Mindhi and Madhurawada is contaminated with traces of heavy metals like lead, cadmium, zinc and mercury.
“It is quite natural that the groundwater in Mindhi will contain traces of heavy metals, as it is almost adjacent to the industrial belt. But it is surprising to find traces of mercury beyond the permissible limits in the groundwater at Madhurawada. The permissible limit is 0.01 ppm and the recorded level is 0.10 ppm. It is likely that the contamination is being carried by the natural flow of the aquifers below the surface. Though metallurgical industries and chemical industries have now established effluent treatment plants, the contamination is the effect of the earlier negligence and the minimal traces have accumulated to form bio-concentration over the years,” says Dr. Prasada Rao.
Heavy metals can act on the enzyme system and cause damage to vital organs like kidney. Mercury can even affect the nervous system.
Many in the department opine that the process of open cast bauxite mining will permanently affect the perennial water sources in the hills that feed the reservoirs in the plains.
“Apart from causing disturbances to the hydrology, the water will be contaminated with galena and aluminium oxide, which will affect the vital organs. One of the major water sources to the city is the Goshtani, and it flows adjacent to the proposed bauxite mining at Raktakonda and Galikonda in Ananthagiri mandal,” says Dr. Prasada Rao.
Industrial pollution
A matter of concern is the finding of traces of poly-cyclic aromatic hydrocarbons in the groundwater in certain areas. This is a cancer or tumour-causing agent. Though it's still in the assessing stage and not fully confirmed, many in the department feel that it is again due to industrial pollution and open stacking of material like coal, coke and sulphur. “There is a possibility of seepage into the groundwater through rainwater, as the provision for storm water drainage is inadequate.
The water at the Town Servicing Reservoir of the GVMC is said to be of good quality. But, as it flows through the numerous labyrinthine lines, it contaminates with the sewer water as they flow adjacent to each other.
“A small leakage can contaminate the water and at some areas the traces of microbes have been found to be in the scale of 15-25 per ml – compared to the permissible limit of 0-5,” says Dr. Prasada Rao.
