Sources of Groundwater Contamination

Designed dischargesOn-site wastewater disposalInjection wellsLand application

Storage, treatment and disposal**LandfillOpen dumpsResidential disposalSurface impoundmentsWaste tailingsWaste pilesMaterial stockpilesGraveyardsAnimal burialAboveground storage tanks*Underground storage tanksContainersOpen burning and detonationRadioactive disposal

Transport and transmissionPipelinesMaterials transport

Activities with incidental releasesIrrigationPesticide applicationFertilizer applicationAnimal feeding operationsDe-icing salt applicationUrban runoffAtmospheric deposition*Mining and mine drainage

Activities altering flow patternsOil and gas production wellsOther wellsExcavation

Natural sourcesSurface-water interaction**Natural leachingSalt-water intrusion

Mine Tailings/AMD

Vineland Chemical

Leaking Underground Storage Tanks

Source: U.S. Environmental Protection Agency, August 7, 2002. Office of Underground Storage Tanks (OUST). U.S. Environmental Protection Agency. Washington D.C. www.epa.gov/swerust1/graphics/ miscpix1.htm. Accessed January 28, 2003.

Oxidation and Reduction Capacities

From Christensen et al, Applied Geochemistry 16(2001).

Vertical Figures

2 Regions at Winthrop Landfill

Dissolved Species mean, mg L-1

DOC Cl - Sulfide Fe2+ Iron BOD COD Arsenic

Central Region 26

14

29

6

53

49

24

15

37

9

8

3

35

23

0.3

0.1

Peripheral Region 16

4

10 2

5

2

2

4

2

4

6

0

1

0

0.01

0.005

2 Regions at Winthrop Landfill

The animated maps that follow show the probability of arsenic exceeding various concentration thresholds in wells of any depth. The maps automatically progress through thresholds of 10, 50, 200 and 400 ppb.

Exceedance of Arsenic Concentration Thresholds

Click to continuehttp://www.es.ucl.ac.uk/research/lag/as/index.htm

As in Bangladesh

Profiles in a Bangladesh Well

From Harvey et al, Science 298 pp. 1602-1606.