The fourth post in our series highlighting some of the contaminants that can be found in water wells. Northeast Water Wells is available to collect samples and test your well water for contaminants anytime.
If you have a private well, regular water quality testing is very important. Northeast Water Wells recommends testing your well at least every two years. Many contaminants cannot be identified by taste or odor, making it difficult for homeowners to know if the water quality of their well has changed.
What are Iron & Manganese?
Iron and Manganese are common metallic elements found in nature. Both are essential in small amounts to all humans. Iron occurs naturally in soil, sediments, ground water and many types of rocks. Manganese is a mineral that naturally occurs in rocks and soil and may also be present due to underground pollution sources. Manganese is seldom found alone in a water supply. It is frequently found in iron-bearing water but it is more rare than iron in water supplies.
What are the current regulations for Iron & Manganese in Well Water?
Both Iron & Manganese fall into the category of Secondary Drinking Water Regulations. There are 15 Secondary Contaminants on this list, they are considered “nuisance chemicals”. The contaminants on the secondary list are not considered a risk to human health at the Secondary Maximum Contaminant Levels (SCMLs). These guidance were established by the EPA to assist well owners in managing their drinking water for taste, odor and color.
The SCML for Iron is 0.3mg/L (milligrams per liter of water) and the SCML for Manganese is 0.05mg/L
What forms are found in well water?
The four forms of iron and manganese commonly found in drinking water are ferrous, ferric, organic and iron bacteria. Normally, water appears clear when first drawn from the cold water faucet. If yours is not, it may contain ferric iron or organic iron. Both color the water. Ferric iron precipitates or settles out. Organic iron does not settle out. In well water, insoluble iron oxide is converted to a soluble form of ferrous (dissolved) iron. Ferrous iron is colorless, but when in contact with air, it oxidizes readily, creating reddish- brown, solid particles that then settle out as ferric oxide. Manganese is similar to iron but forms a brownish-black precipitate and stains. Manganese is less commonly found in groundwater than iron, rarely found alone in a water source, and generally found with dissolved iron.
Why are Iron & Manganese a problem in well water?
High levels of these contaminants can result in discolored water, stained plumbing fixtures, and an unpleasant metallic taste to the water. Iron deposits can build up in pressure tanks, storage tanks, water heaters, and pipelines. Iron-deposit buildup can decrease capacity, reduce pressure, and increase maintenance.
Water containing even a significant quantity of Iron may appear clear when drawn from the tap, but will rapidly turn red upon exposure to air. This process is called oxidation, and involves the conversion of ferrous (dissolved – clear water iron) iron, which is highly soluble, to ferric (precipitated – red water iron) iron, which is largely insoluble. The ferric iron then causes red/brown staining on clothes, fixtures, etc. Iron water also has an unpleasant metallic taste.
In deep wells, where oxygen content is low, the iron/managesebearing water is colorless. Water from the tap will start out clear, but when the water is exposed to air, iron and manganese are oxidized and change from colorless, dissolved forms to colored, solid forms.
Oxidization of dissolved iron particles in water changes the water to white, then yellow and finally to reddish brown solid particles (precipitates) that settle out of the water. Iron that does not form particles large enough to settle out and that remain suspended (colloidal iron) leave the water with a red tint. Manganese is usually dissolved in water, although some shallow wells contain colloidal manganese, leaving a black tint. These sediments are responsible for the staining properties of water containing high concentrations of iron and manganese. The sediments, or precipitates may be severe enough to clog water pipes.
Iron and Manganese can effect the color and flavor of food and water. They may react with the tannins in coffee, tea and some alcoholic beverages to produce a black sludge, effecting both taste and appearance,
Manganese can be a bigger problem in water even when present in smaller concentrations than iron. Iron will cause reddish-brown staining of laundry, porcelain, dishes, utensils and even glassware. Manganese acts in a similar way but causes a brownish-black stain. Soaps and detergents do not remove these stains and use of chlorine bleach may intensify the stains.
Another problem that frequently results from Iron or Manganese in water is Iron or Manganese Bacteria. These are non pathogenic bacteria (not a threat to health) and occur in soil and some surface waters. The bacteria feed on Iron and Manganese in water. Iron bacteria forms reddish brown slime and Manganese bacteria forms brownish black slime. This slime can be detected in toilet tanks and it will clog water systems.
What are the treatment options for Iron & Manganese?
There are several different treatments for Iron & Manganese depending on the cause. Water softeners, aeration, oxidation and filtration treat dissolved iron or manganese. Neutralizing filters are used to raise the pH and filter particles when iron particles are present from the corrosion of pipes and equipment. Particle filters are used to treat oxidized iron and manganese. Chlorination treatments are used to kill iron and manganese bacterias, followed by installation of a filter. Chemical oxidation with chlorine or potassium are used to treat colloidal or organic iron and manganese.
Northeast Water Wells offers a variety of testing packages to take care of all of your water needs. Call today to set up a time for us to collect a sample of your water. All of our testing is done through a state certified analytical lab.
If you live in Massachusetts you can view the guidelines for Well Water Testing here
If you live in New Hampshire you can view the guidelines for Well Water Testing here
Article written by Karen Provencher, Northeast Water Wells