The simplest groundwater pollution definition would be an introduction of certain pollutant(s) into the groundwater which reduces the quality of groundwater making its use very limited, or in some cases impossible. Many different chemicals, and various synthetic products we use today are usually the main causes of groundwater pollution.
Love Canal was one of the most famous examples of groundwater pollution. In 1978, residents of the Love Canal neighbourhood in upstate New York noticed high rates of cancer and an alarming number of birth defects. The reason for this? Organic solvents and dioxins from an industrial landfill, which had been infiltrated into the water supply and evaporated in basements to further contaminate the air. Eight hundred families were reimbursed for their homes and moved, after extensive legal battles and huge media coverage.
It is of vital importance to preserve groundwater because groundwater that is not polluted presents the clearest water on our planet that unlike other other open water sources like rivers and streams hasn't been contaminated but was in fact purified by the cleanest process of them all, namely the natural filtration.
In the future, freshwater resources will become extremely precious, and groundwater could play one of the most important roles in world's global water supply. Therefore we have to do our best not to release pollutants into the ground because they can work their way down into groundwater, and the end result could be the interaction of groundwater contamination with surface waters that often makes the water supplies unsafe for use.