Iron in Drinking Water
Iron is a naturally occurring element that is common in PEI rocks and soils. Iron can occur in well water for two reasons; it may be present in fine sediment particles, or it may be present in dissolved form in the water. A reddish-brown colour to the water, or an accumulation or reddish-brown sediment usually indicates the presence of fine clay minerals are in the water, a situation particularly common with new wells. A very pale yellowish tint to water or the presence of rusty coloured staining of fixtures may suggest the presence of elevated levels of dissolved iron in the water. Dissolved iron is usually associated with groundwater with low oxygen levels such as may be the case in swampy areas, and is often found associated with high manganese levels as well.
What are the health concerns?
Iron is considered to be an essential element for humans and at the concentrations found in groundwater, it is not considered to be a threat to health. Elevated iron levels can be of concern for aesthetic reasons, because of up-pleasant tastes, staining of laundry or fixtures and encrustation in water pipes. To minimize these problems, The Guidelines for Canadian Drinking Water Quality include and aesthetic objective for iron of 0.3 mg/L.
What are the treatment options?
The method for dealing with elevated iron levels depends on the source of the iron. If iron is associated with fine sediment in the water, and the well is relatively new, continued pumping may clean loose sediment from the well and address the problem. In other cases, relocating the depth of the pump in the well, or reducing the pumping rate may help, or a sediment filter can be installed between the well and the household plumbing.
If iron is present in the water in dissolved form, water treatment may be required, and it is recommended that advice from a qualified groundwater professional be sought prior to deciding what solution best meets your particular situation. Because the undesirable effects of iron can effect a variety of domestic water uses, generally water for the whole household is treated (ie point of entry treatment systems). The most common water treatment devices for reducing iron are greensand filters although for iron levels that are only slightly elevated, the use of a water softener may also be effective.
The Department does not recommend specific brands of treatment devices; however, it is recommended that purchase devises bearing a label that indicates it has been certified to NSF/ANSI Standard 44 for Cation Exchange Water Softeners or NSF/ANSI Standard 61(for drinking water system components – health effects).
As with the use of any drinking water treatment device, the effectiveness of treatment should be verified by sampling after installation. In addition, it is important to ensure the device is used and maintained according the manufacturer’s directions and its performance periodically confirmed by sampling.