Arsenic Levels in Maine Water


Is your well safe? ~ By Gina Philippon

Several news outlets have been reporting recently about the concern of elevated levels of arsenic in Maine water supplies.  While this is frightening, it can be treated relatively easily.

What is Arsenic?

Arsenic is a tasteless, odorless, colorless metalloid element with an atomic number of 33.   It is a naturally occurring element but some rocks and minerals have a higher concentration than others.  Due to the health issues that arsenic exposure can cause, in 2001 the U.S. Environmental Protection Agency reduced the acceptable levels of Arsenic in drinking water from 50 ppb to 10 ppb.  Some of the health issues from arsenic exposure include diabetes, vascular disease, skin, lung, bladder and kidney cancers and lower intelligence levels in children.


According to the United States Geological Survey, New England has some of the highest concentrations of Arsenic in the continental United States.  Here in Maine, the trouble areas are south-central Maine, the Midcoast and Downeast.  While the Maine State Drinking Water Program enforces maximum contaminant levels in public water supplies, there is no administrative authority having oversight for private wells.  In Maine, 40% of the population gets its drinking water from private wells and that number is much higher in rural areas.


Do you have Arsenic?

Owners of private wells should have their water tested every 3-5 years.  Tests should be performed at a State Certified Lab but a homeowner can draw the sample to submit for testing.  MCES has test kits available at no charge for A&L Laboratories in Auburn and Maine Coast Lab in Wiscasset.  A test for strictly Arsenic may be as low as $25.00 and a comprehensive analysis including bacteria, pH, alkalinity, nitrates, chlorides, hardness, iron, manganese and radon along with the arsenic could be in the $100.00 range, a small price to pay for this important knowledge of your water quality.


What to do about it:

There are several ways to remediate Arsenic from a private well.  These include point-of-use reverse osmosis systems. Though inexpensive, an RO system will only provide a small quantity of treated water at a single tap.  RO systems force water through a selective membrane with microscopic pores sized to allow only water molecules through, mechanically filtering the larger contaminant molecules.  RO units typically waste up to 2 gallons of water for every gallon of treated water produced.  These are not a good option for low production wells and water temperature will affect production.


Another method of treatment is the ion exchange method.  In plain terms, it is a brine regenerated water softener.  These systems move water through a resin bed which is charged with ions from dissolved salt.  The benefits are that it is a point-of-entry conditioner and also removes mineral hardness, iron, manganese and sediment from the water.  Disadvantages are if the system fails all of the arsenic trapped in the resin bed can be returned to the water supply and the other constituents in the water compete with the arsenic for resin space reducing effectiveness.


A relatively new and promising method to remove arsenic is an iron oxide filter.  Unlike the ion exchange conditioners, the iron oxide filter granules have a large amount of surface area and have an affinity for arsenic, so much so that they are effective at removing both AS3 and AS5.   These filters can be installed as a smaller inline cartridge for a single fixture or as a point-of-entry for whole house filtration.  The disadvantage is that the media must be replaced on a regular basis and the presence of other contaminants can reduce effectiveness.


Call the office at Mid-Coast Energy Systems today to discuss testing and remediation options for arsenic or any other nuisance issues that you have with your water.  Nothing is more important than pure, clean, safe water.