All wells are not equally vulnerable to contamination
because of differences in three factors: the general aquifer chemistry,
groundwater age, and paths within aquifer systems that allow water and
contaminants to reach a well. More than 100 million people in the United States
receive their drinking
water from public groundwater systems, which can be
vulnerable to naturally occurring contaminants such as radon, uranium, arsenic,
and man made compounds, including fertilizers, septic tank leachate, solvents
and gasoline hydrocarbons.
An aquifer is an underground bed or
layer of permeable rock, sediment, or soil that yields water. Some aquifers are
potable (drinkable) and some are not based on their chemistry (What is
dissolved in the water).
Ground water age is a factor of how
fast does the water recharge in the aquifer. The recharge rate will affect the
aquifer water chemistry.
The path that the ground water
takes underground may bypass sources of contamination or it may go through