Remediation: Techniques and Cost - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 403

Water table

LNAPL

Seep

DNAPL

FIGURE 11.30
Contaminated groundwater migrating toward surface water. (From United States Environmental Protection
Agency (USEPA), Proceedings of the Ground-Water Surface-Water Interactions Workshop , EPA/542/R-00-007, Office
of Solid Waste and Emergency Response, Washington, DC, 2000.)

• There is complete identification of the contaminants. Identifying potential con-
taminants will assist with where and how to monitor potential contaminant path-
ways (e.g., shallow groundwater, deep groundwater, air, or sediment).
• Urban factors, including stormwater discharge and modifications to the natural
geological setting are assessed and measured.
• Historical modifications to the urban environment such as redevelopment and
landfilling are accounted for.
• Pollution prevention programs and initiatives are created to minimize or elimi-
nate future impacts.
• There is adequate public awareness, and the changes required are convenient to
implement. A relevant example is the growth of recycling programs due to the
increased convenience of curbside recycling.

11.9 Air Remediation
As with surface water, the preferred approach to cleaning up polluted air is pollution pre-
vention. When accidental releases occur, they are addressed through emergency response
actions involving evacuation in the downwind direction, air monitoring, and source con-
trol (e.g., stopping the release).
Releases of air contaminants are regulated under the Clean Air Act administered by the
USEPA and enforced by state and local agencies. Many states have also enacted their own
stricter regulations. Air pollution is regulated two ways: (1) through a process requiring
numerous operations to obtain a permit or (2) through inspection, such as motor vehicle emis-
sion inspections and testing, which confirm emission standards are not exceeded. Emitters
of air pollution may be regulated by both methods. Industrial operations emitting atmo-
spheric pollutants must obtain a permit, and may be required to install air pollution control
devices to capture pollutants before they are released to the atmosphere (USEPA 2008b).