| Glossary of water tests, recommended limits and health Issues
AB C E to H N to O P R and S T to Z References
Aerobic Bacteria - Bacteria which use oxygen to live, no regulated levels for drinking water. Swimming pools should have no more than 200 colonies/mL
Aggressive Index - This is a value calculated from measured pH, total alkalinity and calcium hardness. This is an indication of how water may affect copper piping. The best values are between 10 and 12. A value below 10.00 indicates the water may be corrosive to pipes. A value above 12 indicates minerals may build up and restrict water flow in the pipes. Similar to Corrosive Index and Saturation Index.
Alkalinity – A measure of carbonate as calcium (CaCO3) in water. Carbonate may be a contributor or detractor of corrosion depending on the pH of the water.
Arsenic - Used as a compound (Lead arsenate) before 1955 in a pesticide in apple orchards and as a wood preservative in pressure treated wood until 2004, but is a naturally occurring metal. Considered a poison and a carcinogen with an allowable level in Drinking water of 10 parts per billion.
Bromine - A disinfectant used in swimming pools, whirl pools and hot tubs. Best range for swimming pools should be 2 to 5 mg/L. Best range for Whirlpools and hot tubs should 4 to 5 mg/L
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Calcium - An essential mineral for the human body and one of the components of hardness. The recommended daily intake of calcium varies by age, from 500 mg/day for 1 to 3 year olds to 1200 mg/day for persons over 51.
Calcium Hardness – A portion of hardness attributed only to calcium. It is usually in the carbonate or sulfate form. The value from this test is used to calculate the aggressive index.
Carbon dioxide – The form of carbonate which forms “sparkling” water and is a corrosive element in water. There are wells in Stamford with some natural carbonation.
Chlorine- A disinfectant used in drinking water, swimming pools, whirl pools and hot tubs. Used to clear any bacterial contamination after work has been performed on a well. Used as an initial treatment to remove Iron bacteria. Chlorine should not be above 4 mg/L in drinking water and 1.0 mg/L at the tap is the standard amount for public drinking water. Best range for swimming pools is between 1 to 3 mg/L and should not exceed 5 mg/L. Best range for whirlpools and hot tubs is between 3 to 5 mg/L and should not exceed 10 mg/L.
Coliform bacteria - A group of bacteria that are common in soil, but should not be present in a well.
Color – The measured amount of color in water. Reported as platinum cobalt units (PCUs) and the limit in drinking water is15 PCUs.
Copper - An essential metal for the human body, but excesses may cause reversible health problems. Most drinking water pipes are made of copper and subject to corrosion from aggressive water, electrolysis and dielectric metals. Copper can stain white porcelain sinks blue, blue-green or yellow even at very low concentrations in the water. Copper is also used as an algaecide in swimming pools and lakes and is a component in some pesticides and pressure treated wood. The recommended daily intake is 1 mg/day, but the Environmental Protection Agency limits concentrations in water to less than 1.3 mg/L, but recommends concentration be less than 1.0 mg/L. Copper will impart a bitter taste and blue-green color to the water at this level. Health issues include gastro-intestinal problems and elevated liver enzymes for long-term exposure. Significant corrosion of copper pipes is indicated if levels in the water are greater than 0.5 mg/L.
Cryptosporidium - A parasite that may be found in drinking water and recreational water in every region of the United States and throughout the world. Cryptosporidiosis is a diarrheal disease caused by microscopic parasites of the genus Cryptosporidium. Crypto has become recognized as one of the most common causes of waterborne disease within humans in the United States. Because Crypto forms a protective outer shell to survive outside warm blooded hosts for long periods of time, it very resistant to chlorine-based and UV disinfectant methods. It is killed by boiling or removed using a 1.0 micron filtration.
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Escherichia coli - Bacteria found in the fecal material of warm-blooded animals, found naturally in the environment, usually not the kind of bacteria that will cause illness. Escherichia coli are the indicator organism for fresh water recreational water and levels should be less than 235 colony-forming units per 100 mL.
Enterococcus - Bacteria used as the indicator organism for marine and estuary water. Includes bacteria that are known to cause human illness. Levels in recreational water should be less than 104 colony-forming units.
Fecal coliform - Bacteria of the coliform group whose usual source is from the waste products of warm blooded animals. This is the indicator organism used for testing water where shellfish are harvested and should be 14 or less.
Fluoride - Is added to public water supplies so that the tap water contains about 1 mg/L to promote dental health. Although fluoride is a common element, it is not present in significant amounts in the Stamford area. The US EPA limits fluoride concentrations to less than 4.0 mg/L in drinking water.
Giardia - A parasite that may be found in drinking water and recreational water in every region of the United States and throughout the world. Giardiasis is a diarrheal disease caused by microscopic single cell parasite, Giardia intestinalis. Giardiasis is also one of the most common causes of waterborne disease within humans in the United States. Giardia also forms a protective outer shell to survive outside warm-blooded hosts for long periods of time, but it is killed or removed by boiling, 1.0 micron filtration, chemical and UV disinfectant methods.
Hardness – The total amount of calcium and magnesium salts in the water. Hard water is considered to be over 200 mg/L, soft water under 80 mg/L. Reported by laboratories as mg/L, although treatment people use grains per gallon, the conversion is found by multiplying mg/L by 0.0584.
Hydrogen sulfide - Known as the “rotten-egg” smell, it is the primary by product of iron and sulfate reducing bacteria when they are growing without oxygen present. It is very noticeable at low levels, but overwhelms the olfactory organs at dangerous levels. Dangerous levels in air are 100 ppm.
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Iron - Although an essential metal for the human body, the iron found in well water is not the kind that the body can use, so it has no effects on health either positive or negative. Iron will cause an orange or brown staining. Limits in drinking water are 0.3 mg/l though staining maybe found in levels as low as 0.1 mg/L. Iron is many times accompanied with bacteria known as Iron bacteria and manganese.
Iron Bacteria - There are many strains of these bacteria, but none are harmful to humans. They feed on iron, manganese and sulfate and make iron and manganese problem appear worse by creating long visual filaments of the metals. They growth with or without oxygen, without oxygen they create the very obnoxious gas, hydrogen sulfide.
Langier index – Similar to the aggressive index, in that it is a calculated value which describes the corrosive potential of the water, but uses the concentration of total dissolved solids instead of calcium harness. Values below –2.0 are considered aggressive, those above 0.0 may cause scale.
Lead - A metal harmful to neurological development in children under the age of 6. Eliminated from the solder used in water pipes and in paint in 1977 and eliminated as a gasoline additive in 1995. It is recommended that all homes built before 1977 have a “first draw” sample of water taken to test for lead. The US EPA recommends that lead levels be less than 15 parts per billion.
Magnesium - Another component of hardness and an essential nutrient for human health. Recommended levels should be as much as 300 mg/day. The form of hardness Magnesium sulfate creates the hardest scale.
Manganese - A metal whose primary concern is a dark brown to black-brown discoloration, but has been linked to mercury-like brain damage at extremely high levels. There are significant taste and odor problem associated with manganese at high levels. Manganese my cause staining at concentrations of 0.05 mg/L, particularly if iron or iron bacteria is also present. There is a maximum contaminant limit of 0.5 mg/L and levels above 5.0 mg/L may cause health problems.
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Nitrite Nitrogen - Nitrite is usually found as a breakdown product of organic material and fertilizer because of bacterial activity. Nitrite has been indicated in a serious anemia for infants under the age of 6 months called Methemoglobinemia. At 0.005 mg/L it is an indicator of bacterial activity and is commonly found in new wells where surface soils with organic matter have been introduced by the drilling process. It may show recent bacterial activity in existing wells, even if a bacteria test shows no organisms. Besides bacteria activity, sources may come from swamps, fertilizer, compost, septic systems, lakes and ponds. There is a maximum contaminant limit of 1.0 mg/L in drinking water.
Nitrate Nitrogen - Nitrate sources include fertilizer, compost, septic systems, lakes and ponds. It is also indicated as the cause of Methemoglobinemia in infants less than 6 months. While there is a maximum contaminant level of 10.0 mg/L, concentrations greater than 5.0 mg/L may indicate contamination from fertilizer and further testing for pesticides is suggested.
Odor – There can be smells associated with well water, some have to do with serious contamination problems, and others are simply annoying. Many petrochemicals can have a very low odor threshold and significant contamination can be detected. Even algae and mosses growing on the ground near the well can impart an odor. Odor is reported in the following way: 0-not detected, 1-very faint, 2-faint, 3-distinct, 4-decided, 5-objectionable and NA-Interferences. Odors levels 2 and above are described to the best of the analyst’s ability.
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Pesticides – Generally, current pesticides break down in ineffective forms and harmless by products with 3 weeks. Pesticides that are no longer in use tended not to break down or had a significant impact on human health in small doses. Current and past practices of pesticide use in the Stamford area have not had an impact on well water. Surveys performed by the State of Connecticut have not found any significant levels of pesticides in this area.
pH – The direct measure of how acid or basic water is. pH actually measures the concentration of hydrogen ion in the water. Neutral is 7.0; the lower acid level for well water is 6.4. While there are some concerns for waters with a pH above 8.5, the upper recommendation is 10.0.
Phosphate - Enters waterways and wells in excessive amount from fertilizer and detergents. In fresh water, it is viewed as the main cause of excessive algae growth. There are no published limits to the amount of phosphate allowed in drinking water.
Potability – Bacteriological potability is the absence of coliform bacteria in drinking water and this is what is generally referred to when calling water “potable”.
Potassium - Is an essential mineral not found in high concentration in soils in Stamford. Potassium salt (KCl) is an alternative to using sodium salt in water softener regeneration. There are no levels where adverse health affects have been documented. The recommended daily intake of potassium is 2000 mg/day.
Pseudomonas – A bacteria implicated in ear infections and commonly found in poorly maintained spas. It should not be present in drinking water, pool water or any spa water.
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Radon – A natural odorless, tasteless gas formed from the radioactive decay of radium. Although a chemically inert gas, it has a half-life of 3.8 days, releasing alpha particles as decays. Radon in the air has been linked to lung cancer and for air there is a defined limit of 4.0 picocurries (pCi/L). With the debate concerning radon in drinking water going on almost twenty years, there are still no Federal or State regulations for radon in drinking water. All homes should test for radon in the air. The issue of radon in water was given to the National Science Foundation who came up with the conclusion that the main issue is radon in air. For homes with wells, if the radon in air was elevated, the radon in water should be checked because there is a general relationship between the two: every 10,000 pCi/L in the water contributes to 1.0 pCi/L in the air. The State of Connecticut has recommended testing for all well water and suggested that the combined limit of radon in air and water should be under 5,000 pCi/L. The average radon level in water in Connecticut is 7,000 pCi/L.
Saturation index – Takes into account each mineral and metal tested for and includes the temperature of the water to determine the corrosive nature of the water. The water has a corrosive nature if the value is less than –2.0 and tends to build scale if the value is greater than 1.0.
Sulfate – A mineral that is part of hardness and usually forms the most difficult scale to remove. Limits in drinking water are 250 mg/L because sulfate imparts a bitter taste and may have laxative effects for persons not accustom to high levels. Levels in Stamford well water are low.
Sodium – An essential metal with a recommended daily intake of 2400 mg/day. Because excess sodium has been linked to heart problems, the recommended limit for persons on physician prescribed sodium restrict diets is 28 mg/L. It is not generally considered a problem for persons who have no restrictions. It is good to reference the amount of sodium to a single large tomato, which has 50 mg of sodium or a McDonalds hamburger, which has 580 mg of sodium.
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Turbidity – A measure of particles in the water, turbidity has no direct links to health problems. High levels may indicate iron or manganese in the water, a problem where sand is kicked up by the pump, a collapse of the well or a bacteria problem.
VOCs – An acronym for volatile organic compounds, which are one portion of hydrocarbon fuels. They should not be present in wells, although on gasoline additive, MTBE is extremely water soluble and present in trace amounts in ground water since its introduction in gasoline.
Zinc – An essential metal with a recommended daily intake of 11 mg/day for adults. The recommended limit in drinking water is 5.0 mg/L because it imparts an undesirable taste.
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References –
USDA website - http://www.cnpp.usda.gov/ Last Modified: 12/06/2007
US EPA website - http://www.epa.gov/safewater/contaminants/index.html#inorganic last updated September 10th, 2007.
CDC website - http://www.cdc.gov/Ncidod/dpd/parasites/cryptosporidiosis/factsht_cryptosporidiosis.htm#1 last reviewed August 19, 2005.
CDC website - http://www.cdc.gov/ncidod/dpd/parasites/giardiasis/factsht_giardia.htm#what last review September 17, 2004
US EPA website - http://www.epa.gov/radon/ last updated October 31st, 2007.
Stateof Connecticut - http://www.epa.gov/radon/index.html last updated 9/20/2007
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