Groundwater quality deteriorates in Chittur region of Palakkad

Kochi: The quality of groundwater in some areas in Chittur region of Palakkad, the rice bowl of Kerala, has deteriorated, a recent study has found. Elevated levels of sodium, potassium and fluoride were seen in collected samples. The region is notable for its position within the ‘Palghat Gap' — a significant break in the Western Ghats mountain range —which climatically receives a relatively low annual rainfall of around 700 mm.The research aimed to identify water quality for drinking and agricultural harvest in the crystalline aquifer, located in eastern Palakkad.A groundwater compatibility study was conducted by analysing major cations, anions, macronutrients, and fluorine in groundwater. Groundwater is the essential source for domestic, agricultural and industrial purposes in eastern Palakkad. When analysis was done, it showed a considerable difference in the groundwater chemistry of phreatic and deeper aquifers. Excess fluoride was noted in a few samples."We regularly studied this area, which is often marked as a semi-critical or critical area by the Central Groundwater Board. Contamination is seen in the aquifer, which calls for better management and the need for recharging it. Often, we find that this aspect of recharging the aquifers is not properly advised or implemented," said E Shaji, Department of Geology, Kerala University, who tracked this region for some years.Shallow groundwater is tapped via excavated wells (3-20 metres below ground level (BGL)) and bore wells (30-60 m BGL) while deeper semi-confined to confined aquifers are accessed through bore wells reaching depths of 100-300 m BGL.An evaluation of groundwater quality based on the WHO drinking standards was carried out, with 48 samples from excavated wells and borewells throughout the study area."This used to be a highly agrarian land, but now people are doing mixed farming in the wake of the water crisis. Rainwater harvesting and better groundwater management will need to be implemented to correct this contamination in the aquifer," Shaji said.It called for regular assessments of agricultural run-off affecting shallow aquifers, along with the implementation of salt-tolerant crops and drainage systems in high-electrical conductivity zones for irrigation operations.