Use of Environmental Isotopic Proxies for Evaluating Geo-Hydrologic and Pollution Aspects of Groundwater on Bangalore City, India

Deljo Davis Somashekar Rk

doi:10.4172/2157-7587.s12-004

Abstract

Water quality data from 81 samples sites (groundwater, surface water and sewage) before and after the monsoonal cycles, aquifer characteristics of Bangalore city were compared to assess the risk of urban development in hydrological environment. Isotopic and physicochemical investigations were carried out to characterize isotopic nature of sewerage and their influence on groundwater in the crystalline aquifer. The similarity of water quality data was assessed using PCA analysis and samples were differentiated as strong to moderate sewerage or geogenic influences. They were compared with the isotopic signature and discriminated as under the control of different sources. From the tritium measurement, it is inferred that groundwater is recharged within 50 years. 14C values is 56 pmC (∼4407 years), indicative of a complex aquifer system in this urban area. Study evaluated the possibilities of isotopic signature for the study of geo-hydrologic and pollution aspects of groundwater in an urban set up.

Highlights

Urbanization changes drastically the hydrologic cycle of natural areas
The geochemical composition of groundwater in the present study indicated a direct relationship between the external influences and the relative abundance of cations
In general most of the lakes except Kalkere and Hebbal lakes are strongly influenced by the precipitation and rest actively receive discharged groundwater

Summary

Introduction

Urbanization changes drastically the hydrologic cycle of natural areas. Buildings, roads, sidewalks, and parking lots make the land surface impermeable to the infiltration of precipitation, diminishing the natural recharge of the aquifer. Artificial recharge from inadvertent leaks and discharges from water sources, such as water supply distribution and sewer systems, septic systems and cesspools, and irrigation of parks, augments aquifer recharge. In urban areas sources and their pathways are very complex and existence of secondary sources like storm water, potable water supplies, waste water or sewages are prominent with the other sources [1,2,3]. Among these sources sewage can affect people’s immediate environments and leads to water related illnesses such as diarrhoea that kills 3-4 million children each year [4]. The impact of urbanisation on the hydrological cycle is complex and it affects almost all hydrological processes [5,6]

Methods

Results

Conclusion