Contaminants: biological (bacteria, viruses), nutrients, metals, synthetic organic chemicals

Carried downward by infiltrating water to water table.
Dissolved contaminants move with groundwater.

With time, some contaminants disappear from water. (reading on aquifer vulnerability from EPA site)

• filtration and absorption onto soils
• natural degradation
• bacterial decay

Aquifers are most vulnerable where:

water table is near surface
no overlying aquiclude

Contaminant Sources: (reading from EPA on contamination sources)

Agriculture:Insecticides, herbicides, fertilizers

Prevention:
reduce runoff
construct filtration marshes and plants

For new septic systems in Florida, a site inspection is required:
to estimate soil permeability
to determine how high the water table is during the wet- season

Prevention: new tanks, monitoring systems

Landfills: leachate can infiltrate into groundwater

Prevention: cap landfill, line landfill, and collect and treat leachate

Superfund program started in 1980 to clean up highest priority toxic waste sites.
Total cost: billions of dollars
 

Superfund process: (Groundwater Clean up at Superfund Sites)
Investigation: identify the extent of contamination
Remediation: cleaning up ( “pump and treat”, bioremediation)
or Containment