Pollutants discharged without being properly treated, have contaminated many rivers and groundwater making them unfit for consumption. This is a major constraint for development and management of drinking water and for producing food.

In this background a geology professor of Andhra University developed numerical index which quantifies an area into zones of relative groundwater pollution activity.

National Mineral Award winner Nandipati Subba Rao, who conducted the study in the river basin of Varaha in Visakhapatnam district, said the results of the study would not only pave the way to identify the intensity of groundwater pollution activities, but also to implement appropriate management strategies by civic authorities at a specific site to reduce pollution. The study was also applicable to assess the intensity of pollution caused by urban wastes and industrial effluents, among others, he said.

Prof. Subba Rao’s paper, “PIG-a numerical index for dissemination of groundwater contamination zones’ appeared in the November 2012 issue of ‘Hydrological Processes’ published by John Wiley & Sons.

He has developed a numerical index on the basis of weighting scheme, taking into consideration of quantities of chemical parameters with respect to their drinking water quality standards for quantification of pollution activity.

For example, if pH, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulphate, nitrate and fluoride exceed their drinking water quality standard limits of 7.5, 500 milligrams per litre (mg/L), they can cause health hazards such as gastrointestinal irritation, improper metabolism, hypertension, renal stones, respiratory problems, blue bay disease and flurosis, among others. “Thus, the study reflects a composite influence of individual chemical parameters on overall water quality of an area”, he said.   Taking the consideration of impact of higher concentration levels of chemical parameters on human health, Prof. Subba Rao said the present study, PIG-pollution index of groundwater, quantifies an area into zones of relative groundwater pollution activity.

“If it is less than 1.0, groundwater pollution activity is insignificant, between 1.0 and 1.5, indicates low groundwater pollution activity, from 1.5 to 2.0 expresses moderate pollution, from 2.0 to 2.5 denotes a high pollution activity.  If it is more than 2.5, it signifies a very high groundwater pollution activity.  Moreover, the study can also distinguish the specific source of contaminant at a particular site”, he said.

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