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GLOSSARY OF WATER QUALITY TERMS
Brought To You By Wilkes University Center for Environmental
Quality,
Geo-Environmental Sciences and Engineering Department
We depend upon water for our very existence. The impact of water quality
and quantity issues has never been greater. Yet the terminology used to
describe the water we drink, the water we provide to plants and animals,
the water stored underground, in lakes, rivers, and oceans, is not well
understood by many.
This listing of water-related terms is intended to reduce the potential
for misunderstanding presentations made by elected officials,
environmental agencies and news reporters. The definitions and
associated explanations provide working knowledge of water. Some
terminology could be defined differently to describe water supply issues
in other locations in the world.
A
B C D E
F G H I
J K L M
N O P Q
R S T U
V W X Y
Z
A
Adsorption: condensation of a gas on the surface of a solid.
Acceptable daily intake (ADI): the chemical ingestion level determined
by combining the maximum No-Observed-Adverse-Effect-Level (NOAEL) with
the addition of an uncertainty (safety) factor. Chemicals with ADI
levels usually are not considered or suspected to be carcinogens. This
classification results from toxicity data collected during prolonged
ingestion studies conducted on a number of animals.
Acidity: the base neutralizing capacity of a water is known as acidity.
Acids contribute to corrosiveness, influence chemical reactions, and
chemical/biological processes. Acidity is determined using a titrametric
or potentiometric method.
Acre-foot: the volume of water (325,851 gallons of water) required to
cover one acre of land with 12 inches of water.
Adsorption: the adherence of gas molecules, ions or solutions to the
surface of solids. For example, odors from freezers and refrigerators
are adsorbed to baking soda.
Advection: the process by which chemicals and heat are transported along
with the bulk motion of flowing gas or liquid. For example, nitrates
move through soils and aquifer formations due predominantly to the bulk
motion or movement of water.
Alkalinity: the acid neutralizing capacity of a water is known as
alkalinity. For surface waters alkalinity has been called "The Protector
of the Stream", since the alkalinity of the water rests sudden changes
in the pH of the stream associated with the influx of acid deposition,
water containing organic acids, groundwater discharges or industrial
wastes.
Most surface waters have alkalinity’s < 200 mg CaCO3/L, but in limestone
areas the alkalinity’s can be greater than 1000 mg CaCO3/L. In some
cases, pristine surface water have very low alkalinity’s and therefore
they would be adversely impacted by acid mine drainage and acid rain.
The alkalinity of precipitation can be from 1 to about 10 mg CaCO3/L.
Typically the best alkalinity for aquatic life is between 100 and 120 mg
CaCO3/L. Alkalinity is determined using a titrametric or potentiometric
method.
Aluminum(Al): there is no published Maximum Contaminant Level (MCL), but
0.2 mg/L is considered safe. Elevated aluminum is believed to be
associated with forms of dementia, such as: Alzheimer’s.
Ammonia (NH4): there is no MCL established for ammonia. Ammonia is very
toxic to fish and aquatic life. Ammonia concentrations of 0.06 mg/L can
cause gill damage in fish and 0.2 mg/L is lethal to trout.
Concentrations in excess of 0.1 mg/L suggest domestic or agricultural
sources of waste.
Anion: a negatively charged chemical. Nitrate and chloride (Cl-) are
examples of anions.
Anion exchange: the chemical process where negative ions of one chemical
are preferentially replaced by negative ions of another chemical. In
water treatment, the net effect is the removal of an unwanted ion from a
water supply. For example, some municipalities are installing anion
exchange systems to remove nitrate from their water supplies.
Antimony (Sb): the maximum contaminant level is 0.006 mg/L. Elevated
levels of antimony can increase blood cholesterol and decrease blood
glucose.
Aquifer: the saturated underground formation that will yield usable
amounts of water to a well or spring. The formation could be sand,
gravel, limestone or sandstone. The water in an aquifer is called
groundwater. A saturated formation that will not yield water in usable
quantities is called an aquiclude. Most Pennsylvania aquifers may be
categorized into confined and unconfined aquifers.
Confined aquifer (artesian aquifer) is the saturated formation between
low permeability layers that restrict movement of water vertically into
or out of the saturated formation. Water is confined under pressure
similar to water in a pipeline. Drilling a well into this type of
aquifer is analogous to puncturing a pressurized pipeline. In some areas
confined aquifers produce water without pumps (flowing artesian well).
When pumping from confined aquifers, water levels often change rapidly
over large areas. However, water levels will generally recover to normal
when pumping ceases.
Unconfined aquifer (water table aquifer) is the saturated formation in
which the upper surface fluctuates with addition or subtraction of
water. The upper surface of an unconfined aquifer is called the water
table. Water, contained in an unconfined aquifer, is free to move
laterally in response to differences in the water table elevations.
Arsenic (As): the MCL for arsenic is 0.05 mg/L. Arsenic is highly toxic
and its prevalence is due to the natural occurrence of this metal and
past use of arsenic in pesticides. Arsenic poisoning typically makes
people feel tired and depressed and this poisoning is also associated
with weight loss, nausea, hair loss, and marked by white lines across
your toenails and fingernails. For freshwater the concentration should
be less than 0.05 mg/L.
Artificial recharge: the unnatural addition of surface waters to
groundwater. Recharge could result from reservoirs, storage basins,
leaky canals, direct injection of water into an aquifer, or by spreading
water over a large land surface.
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B
Barium (Ba): the MCL is 2 mg/L. Barium can increase blood pressure.
Beryllium (Be): the MCL is 0.004 mg/L and it can cause intestinal
lesions.
Baseflow: that part of streamflow derived from groundwater flowing into
a stream.
Biological Oxygen Demand (BOD) : BOD is typically reported as 5 day BOD
and ultimate BOD at 20 C and reported as milligrams of oxygen consumed
per liter (mg O/L). BOD 5 is used by regulatory agencies for monitoring
wastewater treatment facilities and monitoring surface water quality.
BOD is the biochemical oxygen demand of the water and it is related to
the concentration of the bacterial facilitated decomposable organic
material in the water. A sample with a 5 day BOD between 1 and 2 mg O/L
indicates a very clean water, 3.0 to 5.0 mg O/L indicates a moderately
clean water and > 5 mg O/L indicates a nearby pollution source. BOD is a
laboratory test that requires a oxygen sensing meter, incubator,
nitrifying inhibitors, and a source of bacteria.
C
Cadmium (Cd): the MCL for cadmium is 0.01 mg/L. Cadmium poisoning
is associated with kidney disease and hypertension and possibly
mutations. For freshwater the concentration should be less than 0.0004
mg/L.
Calcium (Ca): no specific recommendation, but high calcium is associated
with hardness, total dissolved solids problems and can cause aesthetic
problems.
Capillary Fringe: a zone of partially saturated material just above the
water table. The depth of the fringe depends upon the size and
distribution of the pore spaces within the geologic formation.
Cation: a positively charged chemical. For example, calcium (Ca+2), and
Magnesium (Mg+2) are cations.
Cation Exchange: a process where positively charged ions of one chemical
are preferentially replaced by positive ions of another chemical. For
example, water softeners replace Ca+2, and Mg+2 ions with the sodium
(Na+2) ion.
Chloride (Cl): one of the major anions found in water and wastewater.
The recommended maximum contaminant level is 250 mg/L, since the
chloride ion imparts a salty taste to the water. If ions of Calcium and
Magnesium are present, the chloride ion may not impart a salty taste
until over 1000 mg/L. In addition to human and animal waste, sources of
chloride can include natural geological formations, road salt storage
and applications, oil / natural base drilling, and saltwater intrusions.
High levels of chloride can attack and weaken metallic piping and
fixtures and inhibit the growth of vegetation. Chloride ion is detected
using a titrametric or potentiometric method.
Chlorine: one of a number of forms is added to water to destroy or
deactivate disease-causing microorganisms and is the mostly widely used
disinfectant in the United States. Elevated chlorine levels can great
aesthetic problems (strong taste and odor) and if organic matter is
present it can result in the creation of trihalomethanes, which are
potentially carcinogenic with target organs including the liver and
kidney.
Chemical Oxygen Demand (COD): COD is used as a measure of the oxygen
equivalent of the organic matter content of the sample. Only the organic
matter that is susceptible to oxidation by strong chemical oxidant. COD
is typically used when there are industrial wastewater sources,
comparing biological to chemical oxidation in the selection of treatment
process and performances, or depending on the waste stream it can
provide insight into the concentration of reduced inorganic metal
inorganic, such as ferrous iron, sulfide, and manganese. Chromium (Cr):
The MCL is 0.05 mg/L. The impact of chromium is not clearly defined, but
it is known to adversely impact aquatic organisms.
Conductivity: the theoretical definition of conductivity is the
"reciprocal of the resistance of a cube of a substance 1 cm on a side at
a specified temperature". Typically the units of measure are microhms/cm
(uohms/cm) or microsiemens/cm (uS/cm). Conductivity or specific
conductance is a measure of the ability of a fluid to carry a charge
which is directly related to the concentration of dissolved substances.
As the total dissolved substances in the water increases, the
conductivity of the water also increases. For More information see Total
Dissolved Solids.
Cone of depression: a depression in groundwater levels around a well in
response to groundwater withdrawal or pumping water.
Contaminant: any unnatural biological, chemical, physical, or
radiological substance or matter contained in water. Tri-chloroethylene
(TCE) is a synthetic cleaning solvent sometimes found in groundwater
near manufacturing sites.
Copper (Cu): the MCL is 1 mg/L. At 1 mg/L, the water may taste bitter
and is highly toxic and may disrupt the metabolic processes, especially
for children. For freshwater the concentration should be less than 0.036
mg/L.
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D
Deep Percolation: the movement of water below the maximum effective
plant root zone.
Denitrifying Bacteria: in the process of nitrification of wastewater,
the two key bacteria of ecological importance are nitrosomonas and
nitrobacteria. These bacteria facilitate "catalyze" the reactions.
Nitrosomonas results in the removal of three pairs of electrons from
ammonia facilitating the formation of nitrite and nitrobacteria removes
to electrons from nitrite to form nitrate. The bacteria responsible for
denitrification are autotrophic and heterotrophic facultative anaerobes.
Monitoring for denitrifying bacteria is typically done to monitor the
performance of denitrification systems.
Diffusion: a process where heat or chemicals are transported in response
to differences in chemical concentration or temperature. Movement is
from high concentration (or temperature) to low concentration (or
temperature). This process could involve liquids, gases and solids.
Discharge Area: an area where groundwater moves toward or is delivered
to the soil surface. Groundwater can flow into springs, or seeps;
contribute baseflow to streams; or provide supplemental water for plant
use.
Dispersion: the process whereby a chemical, contained in water, deviates
from the path that would be expected due to bulk flow. In the process
the chemical is mixed with surrounding liquids, causing its
concentration to be reduced.
Distillation: a two-stage water treatment method: 1) the liquid is
boiled, producing water vapor; 2) the water vapor is condensed, leaving
most contaminants behind. Distillation can be used to remove inorganic
chemicals, some non-volatile organic chemicals, and bacteria.
Drawdown: a lowering of the groundwater surface caused by withdrawal or
pumping of water from a well. It is the difference between the static
water level and the pumping water level in a well pumped at a constant
flow rate.
Drainage: the process of transporting surface water over a land area to
a river, lake or ocean (surface drainage), or removal of water from a
soil using buried pipelines that are regularly spaced and perforated
(subsurface drainage).
E
Effluent: the discharge of a contaminant or contaminants with
water from animal production or industrial facilities or waste water treatment
plant.
Erosion: the process or series of processes that removes soils, crop residues,
and organic matter from the land surface in runoff waters, or by wind. Water
droplets begin the erosion process by detaching soil particles. Runoff waters
transport the detached particles to local and regional streams or lakes. Soil
erosion represents the single largest source of nonpoint pollution in the United
States.
Eutrophication: the process of surface water nutrient enrichment causing a water
body to fill with aquatic plants and algae. The increase in plant life reduces
the oxygen content of the water. Eutrophic lakes often are undesirable for
recreation and may not support normal fish populations.
Evapotranspiration (ET): the process of changing soil water into water vapor
through the combination of soil evaporation and plant water use, or
transpiration.
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F
Field Capacity: the amount of water a soil contains after
rapid drainage has ceased. It is the water content following a period of gravity
drainage without the addition of water.
Fecal Coliform: a portion of the coliform bacteria group originating in the
intestinal tract of warm-blooded animals that pass into the environment as
feces. Fecal coliform often is used as an indicator of the bacteriological
safety of a domestic water supply.
The fecal coliform bacterial densities will be determined using the membrane
filtration technique. The MF procedure uses an enriched lactose medium and an
incubation temperature of 44.5 + 0.2oC. Fecal coliform is bacteria typically
found in the feces of warm blooded mammals. Fecal coliform colonies produced by
the M-FC medium are blue, while non-coliform colonies are pale yellow, gray, or
cream color. Since fecal coliform is found in mammalian waste, it is recommended
that fecal coliform be absent from potable water.
Fecal Streptococcus: he fecal streptococcus group consists of a number of
species of the genus Streptococcus, such as: S. faecalis, S. faecium, S. avium,
S. bovis, S. equinus, and S. gallinarum. Fecal Streptococci are typically found
in the gastrointestinal tract of warm blooded animals. Due to the
variation in survival rates the ratio of FC/FS should not be used as a
means of differentiating human and animal sources of bacterial
contamination. Fecal streptococcus colonies produced by the KF-Streptococcus broth are red. For
potable water, the fecal streptococcus should be absent.
G
Gaining Stream (effluent stream): a stream or portion of a
stream where flow increases because of discharge from groundwater.
Grains Per Gallon: a unit of measurement often used to describe water hardness.
One grain per gallon is approximately equal to 17 ppm of various cations.
Groundwater (sometimes written as two words) is water that occupies voids,
cracks, or other spaces between particles of clay, silt, sand, gravel or rock
within the saturated formation.
Groundwater Mining: the removal of groundwater from an aquifer in excess of the
rate of natural or artificial recharge. Continued groundwater mining reduces the
groundwater supply until it is no longer an economical source of water.
Groundwater Recharge: the process where water enters the soil and eventually
reaches the saturated zone. Recharge varies from place to place due to the
amount of rainfall, infiltration, and surface vegetation.
H
Hardness: the hardness of a water is a measure of the
concentration of the multivalent cations (positively charged particles) in the
water, but primarily it is equivalent to the calcium and magnesium concentration
of the water. Hardness is typically reported as mg /L as CaCO3 (calcium
carbonate), but it may also be reported as grains per gallon (1 gpg (US) = 17.12
mg CaCO3/L ). Hardness Classification: Soft: 0 to 17 mg CaCO3/L; Slightly Hard:
17 to 60 mg/L; Moderately Hard 60 to 120 mg/L; Hard 120 to 180 mg/L; and Very
Hard > 180 mg/L.
Health Advisory Level (HAL): a non-regulatory health-based chemical
concentration in drinking water that results in no adverse health risks when a
given amount of water is ingested over exposure periods ranging from one day to
a lifetime.
Heterotrophic Bacteria Plate Count: a procedure for estimating the number of
live heterotrophic bacteria in the water. Colonies may form in pairs, colonies,
clusters or single cells, which can be termed as "colony-forming units". The
colonies are relatively small/compact and do not encroach on each other. This
procedure can accommodate volumes of sample or diluted < 1.0 ml. Test is
typically performed in high purity water, pilot treatment facility performance
evaluations, and pilot scale testing.
Hydraulic Conductivity: a term used to describe the ease with which water moves
through soil or a saturated geologic material. Hydraulic conductivity is
influenced by the type of material comprising the formation (sand, gravel, rock,
limestone, sandstone, clay), the slope of the water table, the type of fluid,
and the degree to which existing pores are interconnected.
Hydraulic Gradient: the slope of the water surface in an aquifer. The hydraulic
gradient indicates the direction groundwater will flow. Water always flows from
higher water table elevations to lower water table elevations. All other factors
being equal, flow is greater when the hydraulic gradient is steeper.
Hydrologic Cycle: describes the constant movement of water above, on, and below
the earth's surface. Processes such as precipitation, evaporation, condensation,
infiltration and runoff comprise the cycle. Within the cycle, water changes
forms in response to the Earth's climatic conditions.
I
Infiltration: the downward entry of water into the soil. The
infiltration rate is a function of surface wetness soil texture, surface residue
cover, irrigation application or precipitation rate, surface topography and
other factors.
Iron (Fe): the MCL is 0.3 mg/L. Iron is a secondary drinking water
standard and primarily regulated because of the aesthetic problems
associated with elevated iron concentrations.
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J
No Available Definitions
K
No Available Definitions
L
Leaching: the removal of dissolved chemicals from soil by the
movement of a liquid (like water).
Lead (Pb): the MCL is 0.05 mg/L. Symptoms of lead poisoning start as: abdominal
pains, constipation, fatigue, depressed appetite and decrease endurance, but
long-term exposure may led to nerve and kidney damage and anemia.
Losing Stream (influent stream): a stream or portion of a stream that discharges
water into the groundwater.
Low Permeability Layers: include soil, sediment or other geologic material that
inhibit water movement. These layers may serve as a base material, or confining
beds for an aquifer. This may be caused by a fragipan or silt clay horizon in
the soil.
M
Magnesium (Mg): no specific recommendation, but high calcium
is associated with hardness, total dissolved solids problems and can cause
aesthetic problems.
Manganese (Mn): the MCL is 0.05 mg/L. Manganese is primarily regulated because
of the aesthetic problems associated with elevated levels of manganese, i.e., a
secondary drinking water standard. Elevated manganese levels can disrupt the
nervous system and regeneration of hemoglobin. For freshwater the concentration
should be less than 1.5 mg/L.
Maximum Contaminant Levels (MCLs): legally enforceable drinking water standards
required by the Safe Drinking Water Act. Standards set by the Environmental
Protection Agency establish the maximum permissible concentration of selected
contaminants in public water supplies. Contaminants are included on the list if
they pose a public health risk. For example, 10 ppm is the MCL for
nitrate-nitrogen (NO³-N).
Maximum Contaminant Level Goals (MCLGs): public drinking water standards that
serve as nonenforceable goals for selected contaminants contained in drinking
water that pose no health risk to people over a lifetime of exposure. A MCLG is
a suggested level set by EPA as a guideline for water utilities.
Mecury (Hg): the MCL is 0.002 mg/L for organic mercury. Mercury has been
associated with kidney disease. For freshwater the concentration should be less
than 0.00005 mg/L.
Methemoglobinemia (blue baby syndrome): the condition that limits the
oxygen-carrying capacity of red blood cells. The condition occurs when bacteria
in the digestive tract convert nitrate to nitrite. Nitrite reacts with
hemoglobin in the blood, producing methemoglobin which cannot carry oxygen. The
resulting oxygen starvation causes a bluish discoloration of the body. The
condition is largely confined to infants less than 9 months old. Excessive
amounts of nitrates may be ingested with water or food. Often foods, such as
fresh vegetables, are a major source of nitrates.
N
Nickel (Ni): MCL has not been established, but for freshwater
the concentration should be less than 0.1 mg/L. Element detected using flame
atomic absorption, no specific standard for nickel. Nickel may cause dermatitis
and nasal irritation.
Non-Point Source (NPS) pollution: the source of surface or groundwater pollution
originating from diffuse areas without well-defined sources. The most common
examples of NPS are chemicals that enter surface water during runoff events from
crop land and turfgrass, and soil erosion from cultivated cropland and
construction sites.
O
No Available Definitions
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P
Part Per Million (ppm): a measure of concentration of a
dissolved material in terms of a mass ratio (milligrams per kilogram, mg/kg).
One part of a contaminant is present for each million parts of water. For water
analysis, parts per million often is presented as a mass per unit volume
(milligrams per liter, mg/l). There are one million milligrams of water in one
liter.
Perched Water Tables: occur when a low permeability material, located above the
water table, blocks or intercepts the downward flow of water from the land
surface. Water mounds up above the impermeable material, creating another
saturated zone with a water table.
Permeability: the property of porous materials indicating the ease with which
liquids or gases will be transmitted through a soil or other porous material.
Permeabilities are not affected by changing the type of liquid.
pH: a numerical measure of the acidity or alkalinity of water. The pH scale
ranges from 1 (acidic) to 14 (alkaline). A pH of 7 is neutral. The technical
definition of pH is that it is a measure of the activity of the hydrogen ion
(H+) and is reported as the reciprocal of the logarithm of the hydrogen ion
activity. Therefore, a water with a pH of 7 has 10-7 moles per liter of hydrogen
ions; whereas, a pH of 6 is 10-6 moles per liter. The pH scale ranges from 0 to
14.
Phosphate (PO4): There is no MCL for phosphate. In surface waters, phosphate is
typically a limiting plant nutrient. The recommend maximum concentration in
rivers and streams is a concentration of 0.1 mg/L of total phosphate.
Point of Entry (POE) Treatment: the treatment of all water entering a house,
farmstead or other facility, regardless of its intended use. Anion exchange is
an example of POE treatment to remove nitrates.
Point of Use (POU) Treatment: treatment of water at the point it is used. A
common example would be water treatment at the kitchen sink for drinking and
cooking uses. Reverse osmosis, distillation and ozone are examples of POU
treatment methods.
Point Source (PS) Pollution: the source of surface or groundwater pollution that
originates from a well-defined source. Examples include: industrial effluent;
large animal containment facilities; city waste water treatment discharges; or
chemical spills. Point sources commonly are associated with pipeline discharges
of some type.
Pollutant: any unwanted chemical or change in physical property that renders a
water supply unfit for its intended use.
Porosity: the ratio of the volume of open spaces or voids to the total volume of
a porous material. For example, a sand and gravel deposit may have 20 percent
porosity. Porosity determines the amount of water that can be stored in a
saturated formation. A saturated formation 100 feet thick with a porosity of 20
percent could store an equivalent water depth of approximately 20 feet.
Potable Water Supply: a source of water that can be used for human consumption.
Precipitation: the process where water vapor condenses in the atmosphere to form
water droplets that fall to the earth as rain, sleet, snow or hail. Nebraska's
long-term annual precipitation varies from 16 inches in the west to 34 inches in
the southeast. Annual deviations can be greater than 30 percent.
Pumping Water Level: the water level in a well when the pump is operating and
water is being removed.
Q
No Available Definitions
R
Recharge Area: the area where water predominantly flows
downward through the unsaturated formation (zone) to become groundwater.
Reference Dose (RfD): the maximum daily exposure to a chemical that is judged to
be without risk of adverse systemic health effects over a person's lifetime. It
formerly was called the Acceptable Daily Intake.
Reverse Osmosis (RO): a water treatment method used to remove dissolved
inorganic chemicals and suspended particulate matter from a water supply. Water,
under pressure, is forced through a semipermeable membrane that removes
molecules larger than the pores of the membrane. Large molecules are flushed
into waste waters. Smaller molecules are removed by an activated carbon filter.
Runoff: precipitation or irrigation water that does not infiltrate but flows
over the land surface toward a surface drain, eventually making its way to a
river, lake or an ocean.
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S
Saturated Formation (zone): the portion of a soil profile or
geologic formation where all voids, spaces or cracks are filled with water. No
air is present. There may be multiple water-bearing formations within a
saturated formation. These water-bearing formations often are separated by
layers of clay or other impermeable layers.
Saturated Thickness (zone): the total thickness of a saturated formation.
Seepage: the movement of water into or through a porous material. Seepage occurs
from canals, ditches, and other water storage facilities. It sometimes is used
to describe water escaping from municipal landfill sites.
Selenium (Se):The MCL is 0.05 mg/L. Selenium is associated with hair or
fingernail loss, numbness of fingers and toes, and circulatory problems. For
freshwater the concentration should be less than 1.5 mg/L.
Shock Chlorination: the addition of chlorine for disinfecting a water supply
system including the well, and all distribution pipelines. Shock chlorination is
recommended when coliform bacteria are detected, or after system repairs.
Treated water, with a concentration of at least 200 ppm, is pumped throughout
the distribution system and allowed to set for at least 24 hours before flushing
with untreated water.
Silver (Ag): the MCL is 0.10 mg/L. Silver is associated with causing
discoloration of the skin. For freshwater the concentration should be less than
0.0003 mg/L.
Sodium (Na): no MCL has been set. For individuals on low sodium diets a general
recommendation of 20 mg/L is used.
Specific Capacity: expresses the productivity of a well. Specific capacity is
obtained by dividing the well discharge rate by the well drawdown while pumping.
Specific Yield: the ratio of the volume of water that will drain from a unit
volume of aquifer by gravity flow.
Spring: the point of natural groundwater discharge to a soil surface, river, or
lake.
Static Water Level: the water level in a well located in an unconfined aquifer
when the pump is not operating. The static water level is the surface of the
water-bearing formation and typically is synonymous with the water table.
Strontium (Sr): no MCL has been set, but the element is analyzed using nitrous
oxide -acetylene flame. The primary concern is the presence of a radioactive
form, known as Strontium-90.
Sulfate (SO4): the drinking water limit is 250 mg/L. Sulfate (SO4-2) is widely
distributed in natural waters, but is typically less than a few mg/L. In
Northeastern Pennsylvania, the primary sources of sulfate in surface waters and
groundwater include: acid mine drainage, acid deposition, and mineral oxidation.
Standard set because of taste and aesthetic problems and sulfates laxative
effects.
Sulfite (SO3): may occur in boilers and boiler feedwaters treated with sulfite
to control dissolved oxygen levels, natural waters containing industrial waste
and in wastewater treatment plant effluents using sulfur dioxide to dechlorinate
the effluent.
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T
Thallium (TI): the MCL is 0.002 mg/L, but a MCL Goal is 0.0005. Thallium is
associated with hair loss, changes in the blood, and kidney, digestive, and
liver problems.
Tin (Sn): no MCL has been established for tin.
Total Kjeldahl Nitrogen (TKN): there is no MCl for total kjeldahl nitrogen. This
parameter is used to measure the total amount of organic nitrogen and is
typically used for surface water and groundwater investigations associated with
domestic or agricultural contamination.
Transmissivity: the capacity of an aquifer to transmit water. It is dependent on
the water-transmitting characteristics of the saturated formation (hydraulic
conductivity) and the saturated thickness. For example, sand and gravel
formations typically have greater hydraulic conductivities than sandstone
formations. The sand and gravel will have a greater transmissivity if both
formations are the same thickness.
Total dissolved solids (TDS): a water quality parameter defining the
concentration of dissolved organic and inorganic chemicals in water. After
suspended solids are filtered from water and water is evaporated, dissolved
solids are the remaining residue. Dissolved solids commonly found in Nebraska
water are calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride
and silica. Total dissolved solid concentrations depend on the geologic material
water passes through in the saturated and unsaturated zone, and the quality of
the infiltrating water. Total dissolved solid contents range from less that 100
ppm in the Small streams to greater than 1,000 ppm near the Susquehanna River in
northeast Pennsylvania.
Turbidity: a measure of the cloudiness or opaqueness of the water and is
measured in nephelometric turbidity units (ntu). The turbidity is influenced by
the amount and nature of suspended organic and inorganic material in water.
Typically, the higher the concentration of the suspended material the greater
the turbidity. The value of 1 ntu is recommend for drinking water, since higher
turbidities could cause aesthetic problems or inhibit the ability of a system to
disinfect the water. The source of turbidity could be fine sand, silt, and clay
(i.e., soil separates); organic material, particles of iron and manganese or
other metal oxides, rust from corroding piping, or carbonate precipitates.
Turbidity measurements are typically not made on surfacewater sources - see
Total suspended solids.
Total Solids: the total amount of solids in the sample, which includes:
dissolved, suspended, and volatile.
Total Suspended Solids: a fixed volume of sample is filtered through a
pre-weighed and washed glass fiber filter. The filter is then rinsed and dried
at 103 to 105 C. The change in the weight of the filter represents the weight of
suspended material. This test is typically done for surfacewater supplies and
wastewater treatment plants. For drinking water, turbidity is parameter that is
typically monitored.
Total Dissolved Solids: is determined by filtering a measured volume of sample
through a standard glass fiber filter. The filtrate (i.e., filtered liquid) is
then evaporated to dryness at a constant temperature of 180 C. High total
dissolved solids may effect the aesthetic quality of the water, interfere with
washing clothes and corroding plumbing fixtures. For aesthetic reasons, a limit
of 500 mg dissolved solids/L is typically recommended for potable water
supplies.
Total Volatile Solids: the residue for previous testing is then ignited at a
temperature of 500 C. The change in the weight represents the amount of
suspended or dissolved solids that are organic in nature or volatilized. The
parameter is typically used in wastewater treatment plants because it provides
an estimate of the organic matter content within the waste stream.
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U
Unsaturated Formation (vadose zone): the soil or other geologic material
usually located between the land surface and a saturated formation where the
voids, spaces or cracks are filled with a combination of air and water.
V
Vanadium (V): currently there is no specific MCL for vanadium. Vanadium may
cause respiratory problems and inhibition of Na and K in ATP production.
W
Watersheds: regional basins drained by or contributing water to a
particular point, stream, river, lake or ocean. Watersheds range in size from a
few acres to large areas of the country.
Water Table: the upper level of a saturated formation where the water is at
atmospheric pressure. The water table is the upper surface of an unconfined
aquifer.
X
No Available Definitions
Y
Yeast and Molds: yeast and molds are fungi. A fungus is a colorless (i.e.,
lacking chlorophyll) plant with practically no differentiation of cell
structure. Yeast are small single-celled forms that reproduce by budding or
spore formation. Molds produce spores for both asexual and sexual reproduction.
Yeast and mold analysis is typically done on air-borne samples and surface
wipes.
Z
Zinc (Zn): the MCL is 5 mg/L, because of problems with the aesthetic
quality due to the taste of zinc.
This is a copyright protected document. To obtain permission to produce,
distribute, or reprint this article, you must obtain permission from Wilkes
University, Center for Environmental Quality, P.O. Box 111, Dallas, PA 18612,
boram@wilkes.edu, copyright@1987.
For More information about the Environmental Quality Center, please contact:
Attn: Mr. Brian Oram,
Professional Geologist (PG)
Laboratory Manager
Wilkes University
GeoEnvironmental Sciences and Engineering Department
PO Box 111
Wilkes-Barre, PA 18766
1-800-572-4444 ext. 4619
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