Environmental Engineering Reference
In-Depth Information
Electronegativity:
The tendency for atoms that do not have a complete octet
of electrons in their outer shell to become negatively charged.
Emergent plants:
Erect, rooted, herbaceous plants that may be temporarily
or permanently flooded at the base but do not tolerate prolonged
inundation of the entire plant.
Enhanced Surface Water Treatment Rule (ESWTR):
A revision of the origi-
nal Surface Water Treatment Rule that includes new technology and
requirements to deal with newly identified problems.
Environment:
The sum of all conditions and influences affecting the life of
organisms.
Environmental sample:
A water sample collected from an aquifer or stream
for the purpose of chemical, physical, or biological characterization
of the sampled resource.
Environmental setting:
Land area characterized by a unique combination
of natural and human-related factors, such as row-crop cultivation
or glacial-till soils.
Ephemeral stream:
A stream or part of a stream that flows only in direct
response to precipitation; it receives little or no water from springs,
melting snow, or other sources, and its channel is at all times above
the water table.
EPT richness index:
Index based on the sum of the number of taxa in three
insect orders—Ephemeroptera (mayflies), Plecoptera (stoneflies), and
Trichoptera (caddisflies)—which are composed primarily of species
considered to be relatively intolerant to environmental alterations.
Erosion:
Process where materials of the Earth's crust are loosened, dissolved,
or worn away and simultaneously moved from one place to another.
Eutrophication:
The process by which water becomes enriched with plant
nutrients, most commonly phosphorus and nitrogen.
Evaporite minerals (deposits):
Minerals or deposits of minerals formed by
evaporation of water containing salts. These deposits are common in
arid climates.
Evaporites:
A class of sedimentary rocks composed primarily of minerals
precipitated from a saline solution as a result of extensive or total
evaporation of water.
Evapotranspiration:
The process by which water is discharged to the atmo-
sphere as a result of evaporation from the soil and surface water
bodies and transpiration by plants.
F
Facultative bacteria:
A type of anaerobic bacteria that can metabolize its
food either aerobically or anaerobically.
Fall line:
Imaginary line marking the boundary between the ancient, resis-
tant crystalline rocks of the Piedmont province of the Appalachian
Mountains and the younger, softer sediments of the Atlantic Coastal
