⇓ Free Chlorine* ⇓
Free Chlorine*: is defined as the concentration of residual chlorine in water present as dissolved gas (Cl2), hypochlorous acid (HOCl), and/or hypochlorite ion (OCl-). The three forms of free chlorine exist together in equilibrium. Cl2 + H2O.; HOCl + H+ + Cl-.; HOCl H+ + OCl-
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⇓ Combined Chlorine* ⇓
Combined Chlorine*: is defined as the residual chlorine existing in water in chemical combination with ammonia or organic amines which can be found in natural or polluted waters. Ammonia is sometimes deliberately added to chlorinate public water supplies to provide inorganic chloramines.
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⇓ Total Chlorine* ⇓
Total Chlorine*: is the sum of free and combined chlorine. When chlorinating most potable water supplies, total chlorine is essentially equal to free chlorine since the concentration of ammonia or organic nitrogen compounds (needed to form combined chlorine) will be very low. When chloramines are present in the municipal water supply, then total chlorine will be higher than free chlorine.
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⇓ pH* ⇓
pH*: is a measure of the acidity or basicity of a solution. It is defined as the cologarithm of the activity of dissolved hydrogen ions (H+). Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations. The pH scale is not an absolute scale; it is relative to a set of standard solutions whose pH is established by international agreement.
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⇓ Turbidity* ⇓
Turbidity*: is a measure of the degree to which the water looses its transparency due to the presence of suspended particulates. The more total suspended solids in the water, the murkier it seems and the higher the turbidity. Turbidity is considered as a good measure of the quality of water.
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⇓ Color* ⇓
Color*: Apparent color is the color of the whole water sample, and consists of color from both dissolved and suspended components. True color is measured after filtering the water sample to remove all suspended material. Testing for color can be a quick and easy test which often reflects the amount of organic material in the water, although certain inorganic components like iron or manganese can also impart color.
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⇓ Hardness* ⇓
Hardness*: Hard water is water that has high mineral content (mainly calcium and magnesium ions) (in contrast with soft water). Hard water minerals primarily consist of calcium (Ca2+), and magnesium (Mg2+) metal cations, and sometimes other dissolved compounds such as bicarbonates and sulfates. Calcium usually enters the water as either calcium carbonate (CaCO3), in the form of limestone and chalk, or calcium sulfate (CaSO4), in the form of other mineral deposits. The predominant source of magnesium is dolomite (CaMg(CO3)2). Hard water is generally not harmful to one's health.
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⇓ Copper & Lead* ⇓
Copper & Lead*: The "lead and copper rule", or LCR, was introduced by the United States Environmental Protection Agency in 1991 to limit the concentration of lead and copper allowed in public drinking water at the consumer's tap, as well limiting the permissible amount of pipe corrosion occurring due to the water itself. It was created following studies that concluded that copper and lead have an adverse effect on individuals. The LCR sought to therefore limit the levels of these metals in water through improving water treatment centers, determining copper and lead levels for customers who use lead plumbing parts, and eliminating the water source as a source of lead and copper. If the lead and copper levels exceed the "action levels", water suppliers are required to educate their consumers on how to reduce exposure to lead. A 2004-2005 study of the LCR by the EPA noted that the system had been effective in 96% of systems.
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⇓ Iron* ⇓
Iron*: Iron is one of the most troublesome elements in water supplies. Making up at least 5 percent of the earth’s crust, iron is one of the earth’s most plentiful resources. Rainwater as it infiltrates the soil and underlying geologic formations dissolves iron, causing it to seep into aquifers that serve as sources of groundwater for wells. Although present in drinking water, iron is seldom found at concentrations greater than 10 milligrams per liter (mg/l) or 10 parts per million. However, as little as 0.3 mg/l can cause water to turn a reddish brown color. Iron is mainly present in water in two forms: either the soluble ferrous iron or the insoluble ferric iron. Water containing ferrous iron is clear and colorless because the iron is completely dissolved. When exposed to air in the pressure tank or atmosphere, the water turns cloudy and a reddish brown substance begins to form. This sediment is the oxidized or ferric form of iron that will not dissolve in water. Iron is not hazardous to health, but it is considered a secondary or aesthetic contaminant. Essential for good health, iron helps transport oxygen in the blood. Most tap water in the United States supplies approximately 5 percent of the dietary requirement for iron. When iron exists along with certain kinds of bacteria, problems can become even worse. To survive, the bacteria utilize the iron, leaving behind a reddish brown or yellow slime that can clog plumbing and cause an offensive odor. This slime or sludge is noticeable in the toilet tank when the lid is removed.
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⇓ Nitrate/Nitrite* ⇓
Nitrate/Nitrite*: Nitrate in water is undetectable without testing because it is colorless, odorless, and tasteless. A water test for nitrate is highly recommended for households with infants, pregnant women, nursing mothers, or elderly people. These groups are the most susceptible to nitrate or nitrite contamination. Nitrate-nitrogen occurs naturally in groundwater, usually at concentrations far below a level of concern for drinking water safety. An initial test of a new water supply is needed to determine the baseline nitrate concentration. Therefore, if the water supply has never been tested for nitrate, it should be tested. The primary health hazard from drinking water with nitrate-nitrogen occurs when nitrate is transformed to nitrite in the digestive system. The nitrite oxidizes iron in the hemoglobin of the red blood cells to form methemoglobin, which lacks the oxygen-carrying ability of hemoglobin. This creates the condition known as methemoglobinemia (sometimes referred to as "blue baby syndrome"), in which blood lacks the ability to carry sufficient oxygen to the individual body cells causing the veins and skin to appear blue. The laboratory will report the nitrate concentration as milligrams per liter (mg/L) or as parts per million (ppm), which are equivalent for the concentrations occurring in dilute aqueous systems, such as: drinking water (1 mg/L = 1 ppm).
Most laboratories report nitrate as nitrate-nitrogen (NO3-N), which is the amount of nitrogen in the nitrate form. Some labs may report total nitrate (NO3-). Be sure to check your test report for which quantity, NO3-N or NO3-, is reported. Use the following to compare the two reporting systems:
10 mg/L nitrate-nitrogen (NO3-N) =44.3 mg/L nitrate (NO3-)
The U.S. Public Health Service recommended limit of 10 mg/L NO3-N in drinking water is used by the EPA as the maximum contaminant level for public water systems. Public water systems are legally defined as those that have 15 or more connections or regularly serve more than 25 persons. These systems must comply with the 10 mg/L NO3-N standard in order to be an approved water supply. EPA requires regular testing of public water systems for nitrate-nitrogen and nitrite-nitrogen and these test results are available from the supplier. If a test indicates that the nitrate-nitrogen concentration of the delivered water exceeds the standard, the public must be notified and treatment must be performed. Often, the treatment may be as simple as blending the water that exceeds the standard with water that has a nitrate-nitrogen concentration less than 10 mg/L such that the average concentration of the delivered water is below the EPA standard.
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⇓ Alkalinity* ⇓
Alkalinity*: Alkalinity refers to the capability of water to neutralize acid. This is really an expression of buffering capacity. A buffer is a solution to which an acid can be added without changing the concentration of available H+ ions (without changing the pH) appreciably. It essentially absorbs the excess H+ ions and protects the water body from fluctuations in pH. In most natural water bodies in Kentucky the buffering system is carbonate-bicarbonate (CO2HCO3 CO32-). The presence of calcium carbonate or other compounds such as magnesium carbonate contribute carbonate ions to the buffering system. Alkalinity is often related to hardness because the main source of alkalinity is usually from carbonate rocks (limestone) which are mostly CaCO3. If CaCO3 actually accounts for most of the alkalinity, hardness in CaCO3 is equal to alkalinity. Since hard water contains metal carbonates (mostly CaCO3) it is high in alkalinity. Conversely, unless carbonate is associated with sodium or potassium which don't contribute to hardness, soft water usually has low alkalinity and little buffering capacity. So, generally, soft water is much more susceptible to fluctuations in pH from acid rains or acid contamination.
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⇓ Pesticides* ⇓
Pesticides*: The term "pesticide" is a composite term that includes all chemicals that are used to kill or control pests. In agriculture, this includes herbicides (weeds), insecticides (insects), fungicides (fungi), nematocides (nematodes), and rodenticides (vertebrate poisons).
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⇓ Coliform & E.coli* ⇓
Coliform & E.coli*: Coliform bacteria are organisms that are present in the environment and in the feces of all warm-blooded animals and humans. Coliform bacteria will not likely cause illness. However, their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system. Most pathogens that can contaminate water supplies come from the feces of humans or animals. Testing drinking water for all possible pathogens is complex, time-consuming, and expensive. It is relatively easy and inexpensive to test for coliform bacteria. If coliform bacteria are found in a water sample, water system operators work to find the source of contamination and restore safe drinking water. There are three different groups of coliform bacteria; each has a different level of risk. Total coliform, fecal coliform, and E. coli are all indicators of drinking water quality. The total coliform group is a large collection of different kinds of bacteria. Fecal coliforms are types of total coliform that mostly exist in feces. E. coli is a sub-group of fecal coliform. When a water sample is sent to a lab, it is tested for total coliform. If total coliform is present, the sample will also be tested for either fecal coliform or E. coli, depending on the lab testing method. Fecal coliform bacteria are a sub-group of total coliform bacteria. They appear in great quantities in the intestines and feces of people and animals. The presence of fecal coliform in a drinking water sample often indicates recent fecal contamination » meaning that there is a greater risk that pathogens are present than if only total coliform bacteria is detected. E. coli is a sub-group of the fecal coliform group. Most E. coli bacteria are harmless and are found in great quantities in the intestines of people and warm-blooded animals. Some strains, however, can cause illness. The presence of E. coli in a drinking water sample almost always indicates recent fecal contamination » meaning there is a greater risk that pathogens are present. A note about E. coli: E. coli outbreaks receive much media coverage. Most outbreaks have been caused by a specific strain of E. coli bacteria known as E. coli O157:H7. When a drinking water sample is reported as "E. coli present" it does not mean that this dangerous strain is present and in fact, it is probably not present. However, it does indicate recent fecal contamination. Boiling or treating contaminated drinking water with a disinfectant destroys all forms of E. coli, including O157:H7.
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⇓ Legionella* ⇓
Legionella sp.*: The presence of large numbers of Legionellae in water distribution systems and in industrial waters, including cooling tower environments, presents a potentially serious health risk to both workers and the general public.
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⇓ BOD5* ⇓
BOD5*: The amount of dissolved oxygen consumed in five days by biological processes breaking down organic matter.
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⇓ Chloride* ⇓
Chloride*: is a salt compound resulting from the combination of the gas chlorine and a metal. Some common chlorides include sodium chloride (NaCl) and magnesium chloride (MgCl2). Chlorine alone as Cl2 is highly toxic, and it is often used as a disinfectant. In combination with a metal such as sodium it becomes essential for life. Small amounts of chlorides are required for normal cell functions in plant and animal life. Chlorides are not usually harmful to people; however, the sodium part of table salt has been linked to heart and kidney disease. Sodium chloride may impart a salty taste at 250 mg/l; however, calcium or magnesium chloride are not usually detected by taste until levels of 1000 mg/l are reached. Public drinking water standards require chloride levels not to exceed 250 mg/l.
Chlorides may get into surface water from several sources including:
rocks containing chlorides,
agricultural runoff,
wastewater from industries,
oil well wastes, and
effluent wastewater from wastewater treatment plants.
Chlorides can corrode metals and affect the taste of food products. Therefore, water that is used in industry or processed for any use has a recommended maximum chloride level. Chlorides can contaminate freshwater streams and lakes. Fish and aquatic communities cannot survive in high levels of chlorides.
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⇓ COD* ⇓
COD*: In environmental chemistry, the chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water (e.g. lakes and rivers), making COD a useful measure of water quality. It is expressed in milligrams per liter (mg/L), which indicates the mass of oxygen consumed per liter of solution. Older references may express the units as parts per million (ppm).
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⇓ Conductance* ⇓
Conductance*: Electrical conductance is a measure of how easily electricity flows along a certain path through an electrical element. The SI derived unit of conductance is the siemens (also called the mho, because it is the reciprocal of electrical resistance, measured in ohms). Oliver Heaviside coined the term in September 1885[citation needed].
Electrical conductance is related to but should not be confused with conduction, which is the mechanism by which charge flows, or with conductivity, which is a property of a material.
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⇓ Oil & Grease* ⇓
Oil & Grease*: The presence of oil and grease in domestic and industrial waste water is of concern to the public because of its deleterious aesthetic effect and its impact on aquatic life. Regulations and standards have been established that require monitoring of oil and grease in water and waste water. This test method provides an analytical procedure to measure oil and grease in water and waste water.
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⇓ Phosphorous* ⇓
Phosphorous*: Phosphorus in the environment and the reasons why this nutrient needs to be treated by wastewater treatment plants. The different forms of phosphorus and how one needs to convert organic and condensed forms of phosphorus to orthophosphate, an easily measurable form for analysis.
As with all chemical analyses, accurate results start with the cleanliness of the sampling equipment and with proper sample protocol. These are especially important when a low level of detection must be achieved, a level at which many wastewater treatment plants that remove phosphorus must meet.
Samples for phosphorus analyses can be collected in either glass or plastic containers. Prior to sample collection, wash containers with a non-phosphate detergent, rinse with hot dilute hydrochloric acid, then follow with several rinses of reagent water.
For total phosphorus analysis, the sample must be immediately acidified to a pH below 2 using sulfuric acid and then cooled to 4 degrees C. Samples preserved this way can be stored up to 28 days. However, if only the simpler form of phosphorus (orthophosphate) needs to be determined, filter the sample through a 0.45-micron pore diameter membrane filter (this is the same type of filter you would use for coliform analyses), then cool to 4 C. Analyze orthophosphate within 48 hours.
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⇓ Salinity* ⇓
Salinity*: When we measure the salinity of water, we look at how much dissolved salt is in the water, or the concentration of salt in the water. Concentration is the amount (by weight) of salt in water and can be expressed in parts per million (ppm). Here are the classes of water:
Fresh water - less than 1,000 ppm
Slightly saline water - From 1,000 ppm to 3,000 ppm
Moderately saline water - From 3,000 ppm to 10,000 ppm
Highly saline water - From 10,000 ppm to 35,000 ppm
Ocean water has a salinity that is approximately 35,000 ppm. That's the same as saying ocean water is about 3.5% salt. Sometimes, salinity is measured in different units. Another common unit is the psu (practical salinity units). Ocean water has a salinity of approximately 35 psu. Scientists measure salinity using a CTD instrument (CTD = conductivity, temperature, depth).
Ocean water is about 3.5% salt. That means that if the oceans dried up completely, enough salt would be left behind to build a 180-mile-tall, one- mile-thick wall around the equator. About 90 percent of that salt would be sodium chloride, or ordinary table salt. Chlorine, sodium and the other major dissolved salts.
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⇓ Solids* ⇓
Solids*: Water is a good solvent and picks up impurities easily. Pure water -- tasteless, colorless, and odorless -- is often called the universal solvent. Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. Total dissolved solids (TDS) comprise inorganic salts (principally calcium, magnesium, potassium, sodium, bicarbonates, chlorides and sulfates) and some small amounts of organic matter that are dissolved in water.
TDS in drinking-water originate from natural sources, sewage, urban run-off, industrial wastewater, and chemicals used in the water treatment process, and the nature of the piping or hardware used to convey the water, i.e., the plumbing.. In the United States, elevated TDS has been due to natural environmental features such as: mineral springs, carbonate deposits, salt deposits, and sea water intrusion, but other sources may include: salts used for road de-icing, anti-skid materials, drinking water treatment chemicals, stormwater and agricultural runoff, and point/non-point wastewater discharges.
In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water. Therefore, the total dissolved solids test provides an qualitative measure of the amount of dissolved ions, but does not tell us the nature or ion relationships. In addition, the test does not provide us insight into the specific water quality issues, such as: Elevated Hardness, Salty Taste, or Corrosiveness. Therefore, the total dissolved solids test is used as an indicator test to determine the general quality of the water. The sources of total dissolved solids can include all of the dissolved cations and anions, but the following table can be used as a generalization of the relationship of TDS to water quality problems. Total Suspended Solids (TSS) is comprised of organic and mineral particles that are transported in the water column. TSS is closely linked to land erosion and to erosion of river channels. TSS can be extremely variable, ranging from less than 5 mg L-1 to extremes of 30,000 mg L-1 in some rivers. TSS is not only an important measure of erosion in river basins, it is also closely linked to the transport through river systems of nutrients (especially phosphorus), metals, and a wide range of industrial and agricultural chemicals.
In most rivers TSS is primarily composed of small mineral particles. TSS is often referred to as 'turbidity' and is frequently poorly measured. Higher TSS (>1000 mg L-1 may greatly affect water use by limiting light penetration and can limit reservoir life through sedimentation of suspended matter. TSS-levels and fluctuations influence aquatic life, from phytoplankton to fish. TSS, especially when the individual particles are small (< 63µm), carry many substances that are harmful or toxic. As a result, suspended particles are often the primary carrier of these pollutants to lakes and to coastal zones of oceans where they settle. In rivers, lakes and coastal zones these fine particles are a food source for filter feeders which are part of the food chain, leading to biomagnification of chemical pollutants in fish and, ultimately, in man. In deep lakes, however, deposition of fine particles effectively removes pollutants from the overlying water by burying them in the bottom sediments of the lake. In river basins where erosion is a serious problem, suspended solids can blanket the river bed, thereby destroying fish habitat.
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⇓ Sulfate* ⇓
Sulfate*: is a substance that occurs naturally in drinking water. Health concerns regarding sulfate in drinking water have been raised because of reports that diarrhea may be associated with the ingestion of water containing high levels of sulfate. Of particular concern are groups within the general population that may be at greater risk from the laxative effects of sulfate when they experience an abrupt change from drinking water with low sulfate concentrations to drinking water with high sulfate concentrations.
Sulfate in drinking water currently has a secondary maximum contaminant level (SMCL) of 250 milligrams per liter (mg/L), based on aesthetic effects (i.e., taste and odor). This regulation is not a Federally enforceable standard, but is provided as a guideline for States and public water systems. EPA estimates that about 3% of the public drinking water systems in the country may have sulfate levels of 250 mg/L or greater.
The Safe Drinking Water Act (SDWA), as amended in 1996, directs the U.S. Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) to jointly conduct a study to establish a reliable dose-response relationship for the adverse human health effects from exposure to sulfate in drinking water, including the health effects that may be experienced by sensitive subpopulations (infants and travelers). SDWA specifies that the study be based on the best available peer-reviewed science and supporting studies, conducted in consultation with interested States, and completed in February 1999.
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⇓ Giardia Lamblia* ⇓
Giardia Lamblia*: is a protozoan which can exist as a trophozoite, usually 9 to 21 mm long, or as an ovoid cyst, approximately 10 mm long and 6 mm wide. Protozoans are unicellular and colorless organisms that lack a cell wall and are generally invisible to the human eye. Giardia Lamblia is found in drinking water frequented by hikers and campers, as well as places where many residents rely on untreated surface water. When Giardia is ingested by human’s drinking water, Giardia Lamblia symptoms include diarrhea, fatigue, and cramps. The US EPA has a treatment technique in effect for Giardia in water.
Giardia Lamblia Water Treatment -Slow sand filtration or a diatomaceous earth filter can remove up to 99 % of the cysts when proper pretreatment is utilized. Chemical oxidation - disinfection, Ultrafiltration, and reverse osmosis all effectively remove Giardia cysts. Ozone appears to be very effective against the cysts when utilized in the chemical oxidation - disinfection process instead of chlorine. The most economical and widely used method of removing Giardia is mechanical filtration with a filter that has a nominal 1-micrometer pore size. Because of the size of the parasite, it can easily be removed from drinking water with precoat, solid block carbon filter, ceramic, pleated membrane, and string wound sediment filters.
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⇓ Heterotrophic Bacteria* ⇓
Heterotrophic Bacteria*: Heterotrophic plate count (HPC) constitutes a common indicator for monitoring of microbiological water quality in distribution systems (DS). This paper aims to identify factors explaining the spatiotemporal distribution of heterotrophic bacteria and model their occurrence in the distribution system. The case under study is the DS of Quebec City, Canada. The study is based on a robust database resulting from a sampling campaign carried out in about 50 DS locations, monitored bi-weekly over a three-year period. Models for explaining and predicting HPC levels were based on both one-level and multi-level Poisson regression techniques. The latter take into account the nested structure of data, the possible spatiotemporal correlation among HPC observations and the fact that sampling points, months and/or distribution sub-systems may represent clusters. Models show that the best predictors for spatiotemporal occurrence of HPC in the DS are: free residual chlorine that has an inverse relation with the HPC levels, water temperature and water ultraviolet absorbance, both having a positive impact on HPC levels. A sensitivity analysis based on the best performing model (two-level model) allowed for the identification of seasonal-based strategies to reduce HPC levels.
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⇓ Sample Collection* ⇓
Sample Collection*: The success of every analysis begins with the quality and completeness of the Chain of Custody (COC)/ Analytical Services Agreement form. The COC is a written document that refers to the authenticity of the collected samples and is crucial to provide valid, credible and legally sound laboratory test reports. The accuracy of laboratory findings is directly related to the accuracy of the sample collection. The COC is needed to ensure that the sample was collected utilizing proper protocol. Transportation, storage and handling of the sample sometimes influence lab results. Observation of the condition of the sample is important to consider before proceeding with the actual analysis. The lab bears the burden of proving that the sample was received, handled and analyzed by authorized laboratory personnel. For this reason, the lab makes note of any unusual characteristics of the sample.
More information about Sampling
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