Elucidating hydrochemical properties of groundwater for drinking and agriculture in parts of Punjab, India

摘要

Groundwater over-exploitation leading to quality deterioration is an accepted fact, but limited work in this direction has been carried out in the Indian state of Punjab, where groundwater development is 172 %, the highest of any state in India. This paper makes an assessment of the groundwater quality in three administrative blocks of Rupnagar district in Punjab, in two of which groundwater exploitation has already reached about 200 %. Sixty groundwater samples were collected from shallow tubewells and hand pumps in premonsoon season (May, 2013) and were analyzed for major chemical parameters. Analytical results do not show any perceptible deterioration in groundwater quality; all the parameters are well within the permissible limits of the Indian standards, except for electrical conductivity (EC), total dissolved solids (TDS), Ca and Mg, which exceed the desirable limits in few groundwater samples. Abundance of ions in the water samples is in the order: HCO3- > Cl- > SO42- > NO3- and Mg2+ > Ca2+ > N a (+) > K+. Data plotted on the US Salinity Laboratory diagram show that most of the samples fall in the category of C2S1 and C3S1, which makes the groundwater suitable for irrigation in all types of soil. Other chemical indices such as % sodium (% Na), sodium absorption ratio (SAR), and residual sodium carbonate (RSC) also show that almost all samples are fit for irrigation purposes. This work thus concludes that groundwater quality deterioration due to irrigation has not yet been well perceived in the state of Punjab, even if much of its groundwater resources have been over-exploited. However, the paper warns against indiscriminate drilling and over-exploitation of the groundwater resources for their long-term usage and sustainability.