Environmental Engineering Reference
In-Depth Information
Asthenosphere:
upper portion of the mantle.
Asbestos:
a name applied to a group of six different fibrous minerals including amosite,
chrysotile, crocidolite, and the fibrous forms of tremolite, actinolite, and
anthophyllite.
Atomic mass:
the mass of an atom. Also referred to as atomic weight.
Atomic weight:
the mass of an atom. Also referred to as atomic mass.
Bacteria:
single-celled organisms.
Bar sediments:
fluvial deposits along a river or stream bank, especially along the inside
portions of a river or stream channel bend.
Bar-top sediments:
sediments deposited on top of bar sediments; typically formed in shal-
low water regions in channels and abandoned channels. Also termed channel-top
sediments.
Base:
any substance that when dissolved in water increases the concentration of the
hydroxide ion OH
−
and raises the pH of the solution.
Baseflow:
groundwater seepage into a stream channel.
Base-neutral-acid compounds:
a group of organic compounds much less volatile than
VOCs. Also referred to as semi-volatile organic compounds.
Basic:
a compound with a pH over 7.
Bedding:
the layering of sediments as they are formed and deposited—also referred to as
stratification.
Bedrock:
the continuous solid rock of the continental crust.
Bentonite seal:
material of low hydraulic conductivity placed above a well screen to min-
imize the potential for the vertical migration of substances into the well. Also
referred to as annular seal.
Benzene ring:
A hexagonal ring arrangement found in benzene and other aromatic com-
pounds, consisting of six carbon atoms with alternating single and double bonds
between them. In derivatives of benzene, each carbon atom is bonded to a hydro-
gen atom or to other atoms or groups of atoms.
Bioaccumulation:
contaminant accumulation in the body of an organism at a concentra-
tion greater than what is generally defined as background or naturally occurring.
Bioremediation:
involves the introduction of microorganisms to a contaminated medium
in an effort to allow natural processes to degrade the contaminants into harmless
substances.
Biotic degradation:
degradation of a substance by microorganisms or fungi.
Bioturbation:
disturbance of sedimentary strata by living organisms such as plants and
worms.
Biphenyl:
organic compound composed of two benzene rings.
Boring:
a hole in Earth drilled for collecting geological, chemical, physical, or other desired
information about the subsurface.
Boring log:
a written record of pertinent information concerning a boring.
Brownfield:
an abandoned, idled, or underutilized industrial or commercial facility.
Cancer:
when cells in the body become abnormal and grow or multiply out of control.
Capillary fringe:
subsurface layer where groundwater seeps up from the water table by
capillary action to fill pore spaces.
Capping:
a remedial method where a barrier is placed over a contaminated area.
Capture zone:
the areal extent where groundwater will be captured by a pumping well.
Carbon cycle:
exchanges of carbon from reservoir to reservoir (e.g., oceans to atmosphere)
by various chemical, physical, geological, and biological processes.
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