CTgeo
GROUNDWATER POLLUTION
slides and text by Raymond L. Frigon, Jr., D.E.P. Bureau of Water Management

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#1 The hydrologic cycle. Precipitation infiltrates soil and recharges groundwater.   Groundwater flows in a down gradient direction through the soil matrix.  Groundwater eventually flows into a surface water body (wetland, lake, river, ocean). Water in the surface water body evaporates into the atmosphere and condenses to form precipitation.
 (Groundwater flow demonstration: glass container filled with sand and water.)
#2 Contaminant migration in groundwater. A contaminant released to soil will migrate down to the groundwater table. The contaminant will disperse in groundwater and migrate in the direction of groundwater flow.
 (Groundwater contamination demonstration: food coloring is added to the groundwater flow demonstration to simulate a released contaminant). The contaminant percolates into the soil until it reaches the groundwater table. The contaminant then disperses in the groundwater as is flows down gradient.
#3 Land uses that contribute to groundwater contamination. Agricultural;
 commercial; industrial; residential; waste management (i.e. landfills). The basic theme is that land use impacts groundwater quality.
#4 Contamination sources.
 Landfill: Precipitation that infiltrates the soil cover of an uncapped landfill will leach various contaminants from the fill material. The leachate that exits uncapped landfills typically contains solvents, petroleum constituents, and elevated metals. Landfill leachate typically has a reddish brown color.
 Groundwater impacted by landfill leachate typically has an abnormal color, a foul odor and high turbidity (dissolved solid content).
 Residential: Residential septic systems are designed to naturally breakdown sanitary wastes. If a septic system fails, harmful bacteria may percolate into groundwater. Also, many household products can adversely impact groundwater quality if they are disposed of down the drain.  Agriculture : Pesticide and fertilizer applications impact groundwater quality. The use of many pesticides have been banned because of their effect on groundwater. Livestock can also impact groundwater. The organic wastes created by livestock can increase the nitrogen content of groundwater.
#5 Containers of common household products that impact groundwater quality when released.
#6 Industrial waste lagoon. Drums containing various chemicals have been illegally disposed of.
#7 Earthmoving equipment exposing fill material at a landfill.
#8 An underground storage tank removed from a gasoline service station. Holes in the bottom of the tank are visible
#9 Drums containing chemicals are stored on a loading dock. The drums are leaking.
#10 Agricultural field. Application of fertilizers, pesticides, and improper storage of silage and manure can impact groundwater quality.
#11 View of a catchbasin. Groundwater may be contaminated if household products are disposed of in catchbasins.