Groundwater is located in soil pore spaces and in the fractures of lithologic formations under subsurface. Pollutants leached to the ground make their way down into groundwater and contaminate an aquifer. The study focuses on the physicochemical and biological quality of groundwater spatially in Kerala to assess its suitability for drinking and understand the type of hydrochemicals and spatial distribution of major ions. Groundwater samples from 98 locations covering all districts in Kerala state, India were collected and analyzed, as per standard protocol. The results revealed that fecal coliform bacteria and pH were exceeding in many places. Nitrates exceeded permissible limits in two samples which contained 45.3 mg/L and 50 mg/L at Kayamkulam (Alappuzha) and Old Munnar (Idukki). Fluorides exceeded the desirable limit (1 mg/L) at Mullackal (1.4 mg/L) and Kalikulam Junction (1.2 mg/L) in Alappuzha district and Kollengode (1.6 mg/L) in Palakkad district. Hydrochemical types, relationship among the physicochemical parameters, characterization of sampling sites according to the physicochemical and biological characters and the spatial distribution of major ions are also discussed.

Fresh water quality has gained substantial attention in recent years throughout the world (Chang, 2004). Groundwater (0.06% of Earth’s available water) is a key source of drinking water among freshwater resources. This relatively small volume is critically important as it represents 98% of the freshwater readily available to humans (Zaporozec and Miller, 2000). India, diverse in terms of population (70% rural and 30% urban) depends on groundwater for drinking and domestic purposes (Reddy et al., 1996 and Jaiswal et al., 2003). Groundwater meets the drinking water requirement of over 50% of Kerala’s population (Kerala Water Authority, 1991; Pillai and Ouseph, 2000; and Roy, 2004).

The physicochemical and biological characteristics of groundwater in a given area are determined by the natural-geological formations (Subramani et al., 2005), weathering, dissolution, precipitation, ion exchange and biological processes (Jeevanandam et al., 2007) as well as anthropogenic activities. Often groundwater is contaminated by non-point sources (agricultural, urban runoff) and point sources (sewage, industrial effluents disposal) in many developing countries including India (Jeevanandam, 2007; and Jain et al., 2010). In the recent years, the unplanned urbanization has influenced the quality as well as quantity of the water, evident from declining groundwater table, higher levels of contamination (Ramachandra and Uttam Kumar, 2008). These factors have necessitated the understanding of groundwater quality in the recent years (Yanggen and Born, 1990).

In Kerala, prevalence of water-borne diseases like diseases of gastrointestinal system (Panikar and Soman, 1984), diarrhea, dysentery, typhoid, worm infestations and infectious hepatitis (Aravindan, 1989; and Kunhikannan and Aravindan, 2000) are attributed to groundwater contamination, especially fecal coliform contamination (Kerala Water Authority, 1991; Radhakrishnan et al., 1996; Calvert and Andersson, 2000; Panicker et al., 2000; Rahiman et al., 2003; Laluraj et al., 2005; Laluraj et al., 2006; Babu et al., 2007; Harikumar and Kokkal, 2009; Rejith et al., 2009; and Varghese and Jaya, 2009). Low pH was reported from many places (Gopinath and Seralathan, 2006; Laluraj and Gopinath, 2006; Vijith and Satheesh, 2007; Harikumar and Kokkal, 2009; and Rejith et al., 2009). Harikumar and Kokkal (2009) have also reported high amount of alkalinity, magnesium, hardness, chloride, calcium and TDS. The contamination of groundwater by chloride, TDS and fluoride were reported by Harikumar et al. (2000); Laluraj et al. (2005); George and Prakasam (2008); and Shaji et al. (2007 and 2009).

Soil And Water Sciences Journal, Soil Health Management, Tree Plantations, Soil Organic Carbon, Rainfed Ecosystem, Biological Productivity, Soil Salinity Development, Low Productivity System, Traditional Farming System, Water Management, Agroforestry System, Agriculture Diversification, Decision Support System, Pest Management.