LAA— Lead Agency Attorney
LADD— Lifetime Average Daily Dose; Lowest
Acceptable Daily Dose
LAER— Lowest Achievable Emission Rate
LAI— Laboratory Audit Inspection
LAMP— Lake Acidification Mitigation
LC— Lethal Concentration. Liquid Chromatography
LCA— Life Cycle Assessment
LCD— Local Climatological Data
LCL— Lower Control Limit
LCM— Life Cycle Management
LCRS— Leachate Collection and Removal
LD— Land Disposal. Light Duty
LD L0— The lowest dosage of a toxic
substance that kills test organisms.
LDC— London Dumping Convention
LDCRS— Leachate Detection, Collection,
and Removal System
LDD— Light-Duty Diesel
LDDT— Light-Duty Diesel Truck
LDDV— Light-Duty Diesel Vehicle
LDGT— Light-Duty Gasoline Truck
LDIP— Laboratory Data Integrity Program
LDR— Land Disposal Restrictions
LDRTF— Land Disposal Restrictions Task
LDS— Leak Detection System
LDT— Lowest Dose Tested. Light-Duty
LDV— Light-Duty Vehicle
LEL— Lowest Effect Level. Lower Explosive
LEP— Laboratory Evaluation Program
LEPC— Local Emergency Planning Committee
LERC— Local Emergency Response Committee
LEV— Low Emissions Vehicle
LFG— Landfill Gas
LFL— Lower Flammability Limit
LGR— Local Governments Reimbursement
LHDDV— Light Heavy-Duty Diesel Vehicle
LI— Langelier Index
LIDAR— Light Detection and Ranging
LIMB— Limestone-Injection Multi-Stage
LLRW— Low Level Radioactive Waste
LMFBR— Liquid Metal Fast Breeder Reactor
LMOP— Landfill Methane Outreach Program
LNAPL— Light Non-Aqueous Phase Liquid
LOD— Limit of Detection
LQER— Lesser Quantity Emission Rates
LQG— Large Quantity Generator
LRTAP— Long Range Transboundary Air
LUIS— Label Use Information System
Laboratory Animal Studies—
Investigations using animals as surrogates
Lagoon— 1. A shallow pond
where sunlight, bacterial action, and oxygen
work to purify wastewater; also used for storage
of wastewater or spent nuclear fuel rods.
2. Shallow body of water, often separated
from the sea by coral reefs or sandbars.
Land Application— Discharge
of wastewater onto the ground for treatment
Land Ban— Phasing out
of land disposal of most untreated hazardous
wastes, as mandated by the 1984 RCRA amendments.
Land Disposal Restrictions—
Rules that require hazardous wastes to be
treated before disposal on land to destroy
or immobilize hazardous constituents that
might migrate into soil and ground water.
Land Farming (of Waste)—
A disposal process in which hazardous waste
deposited on or in the soil is degraded naturally
Landfills— 1. Sanitary
landfills are disposal sites for non-hazardous
solid wastes spread in layers, compacted to
the smallest practical volume, and covered
by material applied at the end of each operating
day. 2. Secure chemical landfills are disposal
sites for hazardous waste, selected and designed
to minimize the chance of release of hazardous
substances into the environment.
Landscape— The traits,
patterns, and structure of a specific geographic
area, including its biological composition,
its physical environment, and its anthropogenic
or social patterns. An area where interacting
ecosystems are grouped and repeated in similar
Documentation of the traits and patterns of
the essential elements of the landscape.
Landscape Ecology— The
study of the distribution patterns of communities
and ecosystems, the ecological processes that
affect those patterns, and changes in pattern
and process over time.
Landscape Indicator— A
measurement of the landscape, calculated from
mapped or remotely sensed data, used to describe
spatial patterns of land use and land cover
across a geographic area. Landscape indicators
may be useful as measures of certain kinds
of environmental degradation such as forest
Langelier Index (LI)—
An index reflecting the equilibrium pH of
a water with respect to calcium and alkalinity;
used in stabilizing water to control both
corrosion and scale deposition.
Large Quantity Generator—
Person or facility generating more than 2200
pounds of hazardous waste per month. Such
generators produce about 90 percent of the
nation’s hazardous waste, and are subject
to all RCRA requirements.
Large Water System— A
water system that services more than 50,000
Laser Induced Fluorescence—
A method for measuring the relative amount
of soil and/or groundwater with an in-situ
Latency— Time from the
first exposure of a chemical until the appearance
of a toxic effect.
Lateral Sewers— Pipes
that run under city streets and receive the
sewage from homes and businesses, as opposed
to domestic feeders and main trunk lines.
Laundering Weir— Sedimention
basin overflow weir.
LC 50/Lethal Concentration—
Median level concentration, a standard measure
of toxicity. It tells how much of a substance
is needed to kill half of a group of experimental
organisms in a given time.
LD 50/ Lethal Dose— The
dose of a toxicant or microbe that will kill
50 percent of the test organisms within a
designated period. The lower the LD 50, the
more toxic the compound.
Ldlo— Lethal dose low;
the lowest dose in an animal study at which
Leachate— Water that collects
contaminants as it trickles through wastes,
pesticides or fertilizers. Leaching may occur
in farming areas, feedlots, and landfills,
and may result in hazardous substances entering
surface water, ground water, or soil.
Leachate Collection System—
A system that gathers leachate and pumps it
to the surface for treatment.
Leaching— The process
by which soluble constituents are dissolved
and filtered through the soil by a percolating
Lead (Pb)— A heavy metal
that is hazardous to health if breathed or
swallowed. Its use in gasoline, paints, and
plumbing compounds has been sharply restricted
or eliminated by federal laws and regulations.
Lead Service Line— A
service line made of lead which connects the
water to the building inlet and any lead fitting
connected to it.
Legionella— A genus of
bacteria, some species of which have caused
a type of pneumonia called Legionaires Disease.
Level of Concern (LOC)—
The concentration in air of an extremely hazardous
substance above which there may be serious
immediate health effects to anyone exposed
to it for short periods.
Life Cycle of a Product—
All stages of a product’s development,
from extraction of fuel for power to production,
marketing, use, and disposal.
Lifetime Average Daily Dose—
Figure for estimating excess lifetime cancer
Lifetime Exposure— Total
amount of exposure to a substance that a human
would receive in a lifetime (usually assumed
to be 70 years).
Lift— In a sanitary landfill,
a compacted layer of solid waste and the top
layer of cover material.
Light Non-Aqueous Phase Liquid
(LNAPL)— A non-aqueous phase liquid
with a specific gravity less than 1.0. Because
the specific gravity of water is 1.0, most
LNAPLs float on top of the water table. Most
common petroleum hydrocarbon fuels and lubricating
oils are LNAPLs.
A long-lasting illumination technology used
for exit signs which requires very little
Limestone Scrubbing— Use
of a limestone and water solution to remove
gaseous stack-pipe sulfur before it reaches
Limit of Detection (LOD)—
The minimum concentration of a substance being
analyzed test that has a 99 percent probability
of being identified.
An environmental policy permitting some degradation
of natural systems but terminating at a level
well beneath an established health standard.
Limiting Factor— A condition
whose absence or excessive concentration,
is incompatible with the needs or tolerance
of a species or population and which may have
a negative influence on their ability to thrive.
Limnology— The study of
the physical, chemical, hydrological, and
biological aspects of fresh water bodies.
Lindane— A pesticide that
causes adverse health effects in domestic
water supplies and is toxic to freshwater
fish and aquatic life.
Liner— 1. A relatively
impermeable barrier designed to keep leachate
inside a landfill. Liner materials include
plastic and dense clay. 2. An insert or sleeve
for sewer pipes to prevent leakage or infiltration.
Lipid Solubility— The
maximum concentration of a chemical that will
dissolve in fatty substances. Lipid soluble
substances are insoluble in water. They will
very selectively disperse through the environment
via uptake in living tissue.
a solid into a liquid.
Liquid Injection Incinerator—
Commonly used system that relies on high pressure
to prepare liquid wastes for incineration
by breaking them up into tiny droplets to
allow easier combustion.
List— Shorthand term for
EPA list of violating facilities or firms
debarred from obtaining government contracts
because they violated certain sections of
the Clean Air or Clean Water Acts. The list
is maintained by The Office of Enforcement
and Compliance Monitoring.
Listed Waste— Wastes listed
as hazardous under RCRA but which have not
been subjected to the Toxic Characteristics
Listing Process because the dangers they present
are considered self-evident.
grain size, texture, and other physical properties
of granular soil, sediment, or rock.
Litter— 1. The highly
visible portion of solid waste carelessly
discarded outside the regular garbage and
trash collection and disposal system. 2. leaves
and twigs fallen from forest trees.
Littoral Zone— 1. That
portion of a body of fresh water extending
from the shoreline lakeward to the limit of
occupancy of rooted plants. 2. A strip of
land along the shoreline between the high
and low water levels.
Local Education Agency (LEA)—
In the asbestos program, an educational agency
at the local level that exists primarily to
operate schools or to contract for educational
services, including primary and secondary
public and private schools. A single, unaffiliated
school can be considered an LEA for AHERA
Local Emergency Planning Committee
(LEPC)— A committee appointed by the
state emergency response commission, as required
by SARA Title III, to formulate a comprehensive
emergency plan for its jurisdiction.
Low Density Polyethylene (LOPE)—
Plastic material used for both rigid containers
and plastic film applications.
Low Emissivity (low-E) Windows—
New window technology that lowers the amount
of energy loss through windows by inhibiting
the transmission of radiant heat while still
allowing sufficient light to pass through.
Low NOx Burners— One
of several combustion technologies used to
reduce emissions of Nitrogen Oxides (NOx.)
Low-Level Radioactive Waste
(LLRW)— Wastes less hazardous than most
of those associated with a nuclear reactor;
generated by hospitals, research laboratories,
and certain industries. The Department of
Energy, Nuclear Regulatory Commission, and
EPA share responsibilities for managing them.
Lower Detection Limit—
The smallest signal above background noise
an instrument can reliably detect.
Lower Explosive Limit (LEL)—
The concentration of a compound in air below
which the mixture will not catch on fire.
Lowest Acceptable Daily Dose—
The largest quantity of a chemical that will
not cause a toxic effect, as determined by
Lowest Achievable Emission Rate—
Under the Clean Air Act, the rate of emissions
that reflects (1) the most stringent emission
limitation in the implementation plan of any
state for such source unless the owner or
operator demonstrates such limitations are
not achievable; or (2) the most stringent
emissions limitation achieved in practice,
whichever is more stringent. A proposed new
or modified source may not emit pollutants
in excess of existing new source standards.
Lowest Observed Adverse Effect
Level (LOAEL)— The lowest level of a
stressor that causes statistically and biologically
significant differences in test samples as
compared to other samples subjected to no