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Absolute - 

100% efficiency at the stated rating of water filtration.
 

Absorb - 

To take in. Many things absorb water.
 

Acid - 

A chemical compound which dissolves in water. Acids have sour taste and turn a vegetable dye called litmus, red. An acid separates into two or more electrically charged parts when it is dissolved in water.
 

Acid Rain - 

The acidic rainfall which results when rain combines with sulfur oxides emissions from combustion of fossil fuels (coal).

Activated carbon - 

Very porous carbon from wood, coal, or lignite heated to very high temperatures to promote active sites where contaminants can be adsorbed from water.
 

Activated carbon adsorption - 

The process of pollutants moving out of water and attaching on to activated carbon.
 

Active ingredient - 

The chemical in a pesticide formulation designed to kill a pest.
 

Adsorption (adsorb) - 

Adhesion of chemicals out of water on to a surface.
 

Aeration - 

The mixing or turbulent exposure of water to air and oxygen to dissipate volatile contaminants and other pollutants into the air.
 

Aggressive water - 

Water which is soft and acidic and can corrode plumbing, piping, and appliances.
 

Alkalinity - 

The measurement of constituents in a water supply which determine alkaline (opposite of acidic) conditions.
 

Aquifer - 

An underground waterway.
 

Artesian well - 

A well drilled into a confined aquifer where enough pressure exists for the water to flow to the surface unaided.

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Backsiphonage - 

Reverse seepage of water in a distribution system.
 

Backwashing - 

Reversing the flow of water through a home treatment device filter or membrane to clean and remove deposits.
 

Bioaccumulation - 

The process by which certain metals and chemical levels in the tissue of organisms increase with higher standing in the food chain.
 

Bioavailable - 

Chemicals or metals that are easily absorbed into the food chain are easily taken up by the intestines in the human body.
 

Biodegrade - 

To decompose by natural means.
 

Biosphere - 

The earth and all its ecosystems.
 

Blinds - 

Water samples containing a chemical of known concentration given a fictitious company name and slipped into the sample flow of the lab to test the impartiality of the lab staff.
 

Brine - 

Highly salty and heavily mineralized water containing heavy metal and organic contaminants. Brine usually accompanies oil and gas deposits which exist far below drinkable groundwater supplies.

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CFCs (chlorofluorocarbons) - 

A class of compounds, used as refrigerants and in other chemical processes, which deplete the ozone layer in the stratosphere.
 

CWSS - 

The national Community Water Supply Survey.
 

Calcium Carbonate - 

A white precipitate that forms in water lines, water heaters, and boilers, etc. in hard water areas; also called scale.
 

Capillary zone - 

Soil area above the water table where water can rise up slightly through the cohesive force of capillary action.
 

Carbonates - 

The collective term for the natural inorganic chemical compounds related to carbon dioxide that exist in natural waterways.
 

Carcinogen - 

A substance that causes cancer.
 

Cistern - 

A tank used to collect rainwater runoff from the roof of a house or building.
 

Coagulation - 

In water treatment, the use of chemicals to make suspended solids gather or group together into small flocs.
 

Cold vapor - 

Special method to test water for mercury.
 

Coliform bacteria - 

Non-pathogenic microorganisms used in testing water to indicate the presence of pathogenic bacteria.
 

Cone of depression - 

Natural depression in the water table around a well during pumping.
 

Confined aquifer - 

An aquifer that lies between two impermeable rock layers.
 

Confluent growth - 

In coliform testing, abundant or overflowing bacterial growth which makes accurate measurement difficult or impossible.
 

Cryptosporidium - 

A protozoan one-half as large as a red blood cell, cryptosporidium is so small and tough that it is very hard to detect, much less kill. It causes acute health problems in healthy individuals and may be fatal to individuals whose immune systems are compromised by illness, old age, or medical treatments. See Protozoan.

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DNA (Deoxyribonucleic acid) - 

basic genetic building block material in chromosomes of a cell nucleus.
 

Daughter - 

The product formed by the decay of a radionuclide; usually a new element.
 

Deionized water - 

Water free of inorganic chemicals.
 

Dental fluorosis - 

Disorder caused by excessive absorption of fluorine and characterized by brown staining of teeth.
 

Detection limit - 

The lowest level that can be determined by a specific analytical procedure or test method. The detection limit of a test is determined by the test method itself or the analytical instrument used in the test. The detection limit for TOX, for example, is generally considered to be around 5 ppb. Therefore, if no organics are detected the result will be expressed as < (less than) 5 ppb.
 

Dispersion - 

The movement and spreading of contaminants out and down in an aquifer.
 

Distillation - 

Water treatment method where water is boiled to steam and condensed in a separate reservoir. Contaminants with lower boiling points than water do not vaporize and remain in the boiling flask.
 

Disinfection byproducts - 

Halogenated organic chemicals formed when water is disinfected.
 

Distilled water - 

Water that has been treated by boiling and condensation to remove solids, inorganics, and some organic chemicals.
 

Duplicates - 

Two separate samples with separate containers taken at the same time from the same place. This is a quality control method. The two results should be very close.

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Ecosphere - 

A plant, like the earth, which is capable of supporting life.
 

Electrons - 

Negatively charged particles orbiting the nucleus of a molecule.
 

Enteric viruses - 

A category of viruses related to human excreta found in waterways.
 

Epidemiology - 

The science which investigates the origin of diseases or abnormalities affecting human populations.

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Fetotoxic - 

Toxic to the fetus.
 

Flocculation - 

Large scale treatment process whereby small particles in flocs are collected into larger particles so their weight causes them to settle to the bottom of the treatment tank. This is accomplished by gentle stirring.
 

Fungicide - 

A pesticide specifically designed to kill fungus.

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GAC (Granular Activated Carbon) - 

pure carbon heated to promote "active" sites which can adsorb pollutants. GAC is used in some home water treatment devices to remove certain organic chemicals and radon.
 

Gamma radiation - 

Electromagnetic ionizing radiation which easily penetrates test biological tissue.
 

Greenhouse effect - 

Natural phenomenon whereby increased C02 and other gases in the atmosphere cause radiation from the sun to be trapped, leading to increases in global temperature and potential large-scale climate changes.
 

Ground water - 

Water from a well or underground aquifer.

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Half-life - 

The time it takes for one-half of a radioactive element or pesticide to decay. Halides or halogens - Chlorine, bromine, or fluorine.
 

Halogenated organic chemical - 

Organic chemical containing chlorine, bromine, or fluorine.
 

Hard water - 

Water containing a high level of calcium, magnesium, and other minerals. Hard water reduces the cleansing power of soap and produces scale in hot water lines and appliances.
 

Heat of vaporization - 

The amount of heat necessary to convert a liquid (water) into vapor.
 

Herbicide - 

A pesticide specifically designed to kill unwanted plants.
 

Hydrologic cycle - 

Natural pathway water follows as it changes between liquid, solid, and gaseous states.

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Impermeable - 

Not permeable; does not permit fluids to pass through.
 

Indicator organisms - 

Microorganisms whose presence is indicative of pollution or of more harmful microorganisms. Coliforms are indicator organisms.
 

Indicator tests - 

Test for a specific contaminant, group of contaminants, or constituent which signals the presence of something else (i.e., coliforms indicate the presence of pathogenic bacteria, high turbidity indicates the possible presence of organics and microbiological contamination, and a positive TOX result indicates the presence of manmade organic chemicals).
 

Inert ingredient - 

Nonreactive components in a pesticide formulation or product used to "carry" the active ingredient.
 

Inorganic chemicals - 

Those chemicals which do not contain carbon; these include nitrates, fluoride, and metals.
 

Insecticide - 

A class of pesticides used to kill undesirable insects.
 

Isotopes - 

Atoms of the same element which have the same number of protons but a different number of neutrons in the nuclei.

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J
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K
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Leachate - 

Water containing contaminants which leaks from a disposal site such as a landfill or dump.
 

Lead - 

A metal known to be toxic since Roman times, lead is still used in faucets today. As an additive to tin, brass, or antimony, lead makes the metal softer and easier to work with. The EPA has set no maximum contaminant (MCL) for lead. The expense of replacing U.S. plumbing systems that contain lead is so astronomical that it can only be done slowly and gradually.

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MCL (Maximum Contaminant Level) - 

the maximum level of a contaminant to allowed in water by federal law. This level is based on health effects as well as currently available treatment methods.
 

Mg/L - 

Milligrams of a contaminant per liter of water; same as parts per million (ppm).
 

Manifest (hazardous waste manifest) - 

Written documentation of a hazardous waste shipment that must accompany the waste from generator, to transporter, to in disposal facility, and be signed by representatives of each company.
 

Method blank - 

Laboratory grade water taken through the entire analytical procedure to determine if the samples are being accidentally contaminated by chemicals in the lab.
 

Mutagen - 

A chemical which causes a change in the genetic makeup of an organism which affects future generations.
 

Mutagenic activity - 

The relative potential for a specific substance, material, or water sample to alter genetic structure and influence subsequent generations.

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NIPDWR - 

National Interim Primary Drinking Water Regulations.
 

NPDES (permits) - 

Issued under the National Pollutant Discharge Elimination System for those companies discharging pollutants directly into waterways in the United States.
 

Neutrons - 

Uncharged particles found in the nucleus of an atom which contribute to the total weight of the atom.
 

Nitrate N0₃ - 

A form of nitrogen most often found in water.
 

Nonpoint source of pollution - 

These are wastes that come from so many sources over such a wide area that they are impossible to pinpoint or regulate. In the spring planting season, wastes from agricultural fields and livestock are a significant source of cryptosporidium, triazines, and nitrates. But suburban lawn chemicals also qualify as nonpoint wastes. Well-meaning attempts to control nonpoint pollution have failed, at least so far, because of an independent mindset in farmers and anti-environmental sentiments in Congress.

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Organic chemicals - 

Defined as chemicals containing carbon. These include: 1.) natural - those from animal and plant life, including coal and oil; and 2.) those synthesized by man - industrial solvents, pesticides, etc.
 

Organic fanning - 

Farming technique which utilizes only natural means to fertilize soil and control pests.
 

Organophosphates - 

A class of organic pesticides containing phosphorus, which interrupts nerve impulses along the central nervous system leading to convulsions, paralysis, and death.
 

Ozone - 

1.) In the lower atmosphere, a colorless toxic gas formed by the reaction of nitrogen oxides and hydrocarbons with sunlight, particularly in urban areas. It contributes to chronic human respiratory disease. 2.) In the stratosphere, absorbs ultraviolet radiation and protects life from excessive ultraviolet doses. 3.) Used as an alternate form of water disinfection.

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PAHs (Polyaromatic hydrocarbons) - 

A class of chemical pollutants formed through the breakdown of other chemicals or substances. For example, the combustion of coal, wood, oil, and certain SOCs results in the formation of PAHs.
 

PH - 

A measure of the acidity or alkalinity of water; the pH scale is from 0 to 14 - seven is neutral, 0 is very acidic, 14 is very alkaline.
 

POE (Point of entry) - 

Water treatment device situated at the point where the water enters the house; treats all water entering the house.
 

POU (Point of use) - 

Home water treatment devices located at the point where the water is used, at or near the faucet.
 

Ppb - 

Parts per billion.
 

Ppm - 

Parts per million.
 

Parameter - 

Test or analytical procedure which: 1.) measures specific chemicals such as pesticides, PCBs or fluoride; or 2.) measures a group of chemicals or a characteristic such as pH, TOX, or hardness.
 

Parent - 

In the process of radioactive decay of one element, a new one is formed. The original elemental is called the parent.
 

Pathogen - 

Microorganism which can cause disease.
 

Phenols - 

A group of SOCs used in the synthesis of a wide variety of chemicals and a ubiquitous class of pollutants.
 

Phthalates - 

A group of SOC chemicals used in plastics manufacturing to make them flexible and pliable. One of the most widespread classes of pollutants due to their usage.
 

Plug - 

Concentrated amount of a contaminant or contaminants existing in soil or groundwater.
 

Plume - 

The area taken up by contaminant(s) in an aquifer.
 

Precipitate - 

A, solid which has come out of an aqueous solution. For example, iron from groundwater precipitates to a rust colored solid when exposed to air.
 
 

Preservative - 

A chemical added to a water sample to keep it stable and prevent compounds in it from changing to other forms or microorganism densities from changing prior to analysis. Protons - Positively charged particles found in the nucleus of an atom.
 

Protozoan - 

Protozoans are organisms, such as cryptosporidium, that have a life-cycle with several stages, some of which allow them to pass through a chlorine disinfection process unharmed.
 

Purge - 

To force a gas through the water sample to liberate volatile chemicals or other gases from the water so their level can be measured.
 

Purgeable organics - 

Volatile organic chemicals which can be forced out of the water sample with relative ease through purging.

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Quadruplicate testing - 

Testing the same sample four times; this is often done as a quality control measure in screening tests like TOC and TOX.
 

Quality assurance - 

Efforts by a laboratory to ensure their test results can be substantiated by other laboratories.
 

Quality control - 

Actions taken by a lab to ensure all variables and factors are considered in the measurement of a sample and the interpretation of data to give a result. quantify - To measure the amount of a chemical or substance in a sample.

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RCRA - 

Resource Conservation and Recovery Act - federal legislation requiring that hazardous waste be tracked from "cradle" (generation) to "grave" (disposal).
 

RO (Reverse osmosis) - 

A water treatment method whereby water is forced through a semipermeable membrane which filters out impurities.
 

Radionuclides - 

Radioactive elements or atoms.
 

Recharge zone - 

The area over which an aquifer is replenished; for a confined aquifer the area would be small, but for an unconfined aquifer the recharge zone would likely be the entire length of the aquifer.
 

Replicate (sample analysis) - 

Analyzing the same sample twice; should yield very similar results.
 

Residual chlorine - 

The level of chlorine existing in the distribution system after chlorination at the drinking water treatment plant. The residual chlorine level will be a function of the level of microorganisms and the potential for additional THM formation in the distribution system.
 

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SOCs (Synthetic Organic Chemicals) - 

Manmade chemicals containing carbon, many are associated with chronic health effects.
 

SPC (Standard Plate Count) or HPC (Heterotrophic Plate Count) - 

A test which directly measures the level of certain bacteria in a water sample.
 

Screening test - 

A test that encompasses a wide range of possible contaminants. Examples are: TOX, TOC, and VOA. See also indicator tests.
 

Sedimentation - 

A large scale water treatment process where heavy solids settle out to the bottom of the treatment tank after flocculation.
 

Skeletal fluorosis - 

A health effect of excess fluoride leading to rheumatic effects, pain, and stiffness.
 

Spikes - 

A quality control measure where a known amount of chemical is added to the sample to determine how well the chemical is recovered from the sample when analyzed.
 

Spring water - 

According to the U.S. Food and Drug Administration, spring water is water that comes out of the ground on its own or is bottled near water that comes out of the ground on its own.
 

Surface impoundment - 

An indented area in the land's surface - pit, pond, US( lagoon - usually unlined and confined by natural means and holds liquid waste.
 

Surface water - 

Water from rivers and lakes. Roughly half of all Americans get drinking water from surface water sources.

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TDS (Total dissolved solids) - 

The sum of all inorganic and organic particulate; TDS is an indicator test usually reserved for wastewater analysis, but is also a measure of the mineral content of bottled water and groundwater.
 

THMs (Trihalomethanes)- 

a class of volatile organic chemicals created as a result of water chlorination.
 

TIC (Tentatively Identified Compounds) - 

In GC/MS analysis, chemicals identified by computer match that are not covered in the specific test method. The accuracy of TIC levels is questionable.
 

TNTC (Too numerous to count) - 

a total coliform test result; too many coliforms to count indicates heavy contamination.
 

TOC (Total Organic Carbon) - 

screening test which measures the amount of organic carbon in the water sample.
 

TOX (Total Organic Halide) - 

screening test which measures the level of level organic chemicals containing chlorine and bromine.
 

Teratogen - 

A chemical or substance which causes abnormal formation of a fetus.
 

Turbidity (Turbid) - 

The interference of light passage by insoluble particulates in water. To water engineers, turbidity means cloudiness. Turbidity in water can be harmless, or it may indicate to water that extra filtration, flocculation, and sedimentation is needed.

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UV (Ultraviolet) - 

Water disinfection treatment method using ultraviolet light.
 

Unconfined aquifer - 

An aquifer that is not confined by impermeable rock above it so water recharge occurs across its entire length.

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VOA (Volatile Organic Analysis) - 

Testing procedure for volatile organic chemicals; also called volatiles scan, volatiles screen, or referred to by specific EPA method number, EPA 601 or EPA 602.
 

VOC (Volatile organic chemical) - 

An organic chemical which can easily dissipate or evaporate into the air.

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Water filter - 

Broad term used to describe different types of water filters.
 

Water table - 

The surface of an unconfined aquifer which fluctuates due to seasonal precipitation.
 

Wet methods - 

A group of water tests usually for determining the presence of inorganic chemicals, like nitrates, fluoride, and dissolved solids. They are called wet methods presumably due to the fact that they generally do not require the use of solvent extraction methods that SOC testing does.