Contaminant Fate and Transport - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 275

• Accidents or collisions involving automobiles where gasoline and oil may be
released, railroad derailments, etc.
• Septic systems
• Sewer leaks
• Landfills and dumps
• Automobile exhaust
• Sumps and dry wells
• Former disposal lagoons
• Animal feed lots
• Injection wells
• Fertilizer application
• Application of pesticides and herbicides
• Application of deicing compounds (i.e., road salts)

Exploring and evaluating fate and transport of contaminants in the environment must
consider the complex interplay between the environment and the contaminant. And, as
Figure 8.1 shows, fate and transport is also influenced by the method and location of con-
taminant release and the volume, mass, and duration of the release. We will break down
and describe these factors influencing the migration of contaminants, degradation of con-
taminants, and then describe how the fate and transport of each group of substances is
influenced by the group's specific chemistry.

Smog
Industrial plant Contaminated

surface water
Spills from
rail accidents

One of numerous
stormwater retention
ponds of urban runoff
Auto exhaust

Fertilizer, pesticide and
herbicide runoff

City/urban runoff

Livestock
feed lot

Seepage of con-
taminated water
from stormwater
retention ponds

Seepage lagoon

Landfill or dump

UST

Buried
drums

Pumping
well

Saltwater

Freshwater

Unconfined
aquifer

Saltwater
intrusion

LNAPL
plume

Ruptured pipeline

Water table

Drywell

Confining unit

Septic tank
and field

Injection well

DNAPL
plume

Confined aquifer

Injected contaminants

Confining unit

Bedrock

FIGURE 8.1
(See color insert.) Sources and locations of contaminant release.