Contaminant Fate and Transport - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 297

Sources Transport/Transformation Removal

Photochemistry
Chemical transformations

Prevailing
winds

Cloud processes

Lightning Dispersion

Vertical
mixing

Industry

Agriculture

Fire

Dry
deposition

Transportation

Wet deposition

Visibility

Sewage
plants

Runoff

Forest
productivity

Estuaries

Drinking water Cultural

resources

Effects

Soils

Soils

Aquatic
ecosystem

Ground water

Agricultural
products

Human
health

FIGURE 8.15
(See color insert.) Sources, transport methods, and removal of air pollution. (From United States
Environmental Protection Agency (USEPA), Latest Findings on National Air Quality: Status and Trends through
2006 , EPA454/R-07-007, Research Triangle Park, NC, 2008a.)

FIGURE 8.16
Dust storm that demonstrates transport and dry depo-
sition of particulates. (From National Oceanic and
Atmospheric Administration (NOAA), The May 29th
dust storm, http://www.crh.noaa.gov/ddc/?n=dust
(accessed June 26, 2010), 2010.)

8.4 Fate and Transport of Contaminants
A brief discussion of the fate and transport behavior of each contaminant group presented
in Chapter 7 follows.

8.4.1 VOCs

VOCs are organic compounds that generally volatilize or evaporate readily under nor-
mal atmospheric pressure and temperatures. They usually have a high vapor pressure,