The Jaffna Peninsula is underlain by Miocene limestone that is considered to have appropriate aquifer properties for groundwater storage and discharge. The absence of perennial rivers or major water supply schemes to the Peninsula highlights the importance of groundwater as the predominant water resource for domestic, industrial and agricultural use. The Jaffna Peninsula has four main aquifer systems, namely Chunnakam (Valikamam area), Thenmaratchi, Vadamaratchi and Kayts, of which the Valikamam area is intensively cultivated in the Jaffna Peninsula. Groundwater can become contaminated, by many of the same pollutants that contaminate surface water. Pollution of groundwater occurs when contaminants are discharged or, deposited on, or leached from the land surface above the groundwater. Environmental contamination by petroleum hydrocarbons is the most common site contamination issue encountered by environmental professionals. Contamination of ground water can result in poor drinking water quality, loss of water supply, degraded surface water systems, high cleanup costs, and high costs for alternative water supplies, and/or potential health problems. Used oil and waste fuel have historically been released to the environment through burning, land filling and indiscriminant dumping, accidental spills and through use as a dust control agent on roads. Heavy metals such as chromium, copper, lead, manganese, nickel and zinc are commonly found in used lubricating oil from friction wear on engine parts and can influence the effect the waste has on human health. Sampling was done along the eight directions at the intersections of five concentric rings of 200 meter distance between with the center being close to the Chunnakam power plants. Hexane gravimetric method used to determine the Fat Oil and Grease (FOG) in this study. FOG was recorded in 40 wells. In each well water sample collected in the top as well in the bottom layer. From the results it was identified that only thirty two samples shows FOG is greater than 2 mg/L and forty eight samples shows FOG less than 2 mg/L. Water quality or suitability for use is judged on the potential severity of problems that can be expected to develop during long-term use. It is, therefore, essential to establish baseline information on water quality and availability to assist in long-term planning whilst ensuring the integrity of supply for the Jaffna Peninsula.
