Groundwater pollution occurs when pollutants make their way into groundwater and contaminate it. A pollutant plume spreads through an aquifer, intersecting with groundwater wells or daylighting into surface water. Pollution can come from septic systems, landfills, wastewater treatment plants, petrol stations, agriculture, and naturally occurring contaminants. Protecting groundwater requires preventing pollution through monitoring aquifers and landfills, replacing old fuel tanks, and strictly regulating toxic waste disposal.

1. WATER CYCLE

2. How are groundwater and surface water
connected?
Percolation and Seepage

3. Groundwater pollution (also called groundwater contamination)
occurs when pollutants are released to the ground and make
their way down into groundwater.
It can also occur naturally due to the presence of a minor and
unwanted constituent, contaminant or impurity in the
groundwater, in which case it is more likely referred to
as contamination rather than pollution.
The pollutant creates a contaminant plume within an aquifer.
Movement of water and dispersion within the aquifer spreads the
pollutant over a wider area.
Its advancing boundary, often called a plume edge, can intersect
with groundwater wells or daylight into surface water such as
seeps and spring, making the water supplies unsafe for humans
and wildlife.

4. The movement of the plume, called a plume front, may be
analyzed through a hydrological transport model or groundwater
model.
Analysis of groundwater pollution may focus on soil
characteristics and site geology, hydrogeology, hydrology, and the
nature of the contaminants.
Pollution can occur from on-site sanitation systems, landfills,
effluent from wastewater treatment plants, leaking sewers, petrol
stations or from over application of fertilizers in agriculture.
Pollution (or contamination) can also occur from naturally
occurring contaminants, such as arsenic or fluoride.
Using polluted groundwater causes hazards to public health
through poisoning or the spread of disease.

7. Earth = the natural filter

15. Groundwater pollution
• Very cold, no bacterial breakdown
• Very slow water movement: recharge
can take 100’s or 1000’s of years
• Pollutants can stick to rocks in aquifer
and pollute new water

16. What Pollutes Groundwater?

17. Natural Sources
Some substances found naturally in rocks or soils, such as iron,
manganese, arsenic, chlorides, fluorides, sulfates, or radio nuclides, can
become dissolved in ground water.
•Septic Systems – faulty privies , drainage systems,
•Improper Disposal of Hazardous Waste
•Landfills - lechates
•Releases and Spills from Stored tanks
•Chemicals and Petroleum Products
•Injection Wells/Floor Drains
•Surface Impoundments
•Sewers and Other Pipelines
•Pesticide and Fertilizer Use
•Improperly Constructed Wells
•Improperly Abandoned Wells
•Mining Activities
•hazardous waste - deep well injection
•leaky underground storage tanks

18. How can we protect groundwater?
• Prevention is the key…
– Monitor aquifers & landfills
– Requirements for old fuel tanks
• Leak detection system
– Stricter regulations on toxic waste disposal
• Above-ground storage of toxic waste