Study of Arsenic in Well Water Answers Important Questions about Bathing and Treatment

Showering and taking a bath in well water high in arsenic are not significant arsenic exposure sources for children and adults, according to a new study by the Maine CDC and US CDC.

This is good news for the tens of thousands of Maine residents who likely have too much arsenic in their well water. Bathing in contaminated well water is one of the top concerns voiced by the more than 700 Mainers who seek well water advice from Maine CDC experts each year.

The study also shows that switching to bottled water or installing an arsenic treatment system at the kitchen sink—real-world solutions used by many Maine residents—effectively reduce arsenic exposure when arsenic levels are below 40 micrograms per liter. This is more good news because these strategies may be less expensive than systems that treat all of the water used in the house.

Reducing exposure is more complicated for people when their well has an arsenic level above 40 micrograms per liter, especially if there are young children in the home. For these residents, the study confirms the importance of using bottled or treated water not only for drinking, but for all beverage and food preparation as well.

Less than 2 percent of Maine wells have arsenic levels above 40 micrograms per liter.

The study examined the amount of arsenic in individuals’ urine in relation to their untreated water arsenic concentration, daily water and food consumption and time spent bathing. Participants were children and adult volunteers from 167 Maine households with well water arsenic levels greater than 10 micrograms per liter, and where residents drank bottled water or water treated at the kitchen sink.

Authored by Maine’s State Toxicologist, Andrew Smith, and colleagues, the study appears in the February 15 edition of Science of the Total Environment.

The Maine CDC thanks all of the study volunteers for their participation and contribution to public health.

Learn More

• Explore data about arsenic in private well water in Maine in the data portal
• Get private well water resources for Maine communities and well owners

Arsenic

There has been publicity recently over the amount of arsenic in the apple juice that many children drink. The Food and Drug Administration (FDA) has issued a statement that there is no evidence of any public health risk from drinking these juices and that FDA has been testing them for years.

Arsenic is a naturally occurring element found in water, air, food, and soil in organic and inorganic forms. Inorganic arsenic compounds can be harmful at high and long-term levels of exposure. Organic arsenic compounds are essentially harmless. Because both forms of arsenic have been found in soil and ground water, small amounts may be found in certain food and beverage products, including fruit juices and juice concentrates.

FDA has been tracking total arsenic contamination in apple and other juices for about six years, since foreign producers started gaining an increasing share of the juice market.

Most people ingest small amounts of arsenic each day from various foods, including rice products and shellfish. One of the big sources of arsenic exposure to be on the lookout for in Maine is arsenic in private well water. Half of Maine families get their drinking water from private wells, and 10% of these wells have arsenic levels above the current drinking water standard of 10 micrograms per liter. Only about 45% of families with wells have tested their well water for arsenic -- if you have a well, make sure you have tested it for arsenic.

For more information about arsenic, see this US CDC fact sheet.