by Megan Schiffres
Residents of Kilmarnock received a message with their water bills last month which caused some alarm, especially among those who have recently moved to the region.
Water utility customers in town were informed the municipal drinking water supply has a concentration of fluoride which is higher than the recommended level set by the Environmental Protection Agency (EPA).
Fluoride is a naturally occurring mineral which, in small quantities, can help strengthen teeth and prevent cavities. Many communities across the U.S. add fluoride to their drinking water systems in order to provide their citizens with these dental benefits, but in the Northern Neck, fluoride enters the drinking water naturally through the aquifers supplying the area’s water, which flows through rocks and sediments rich in fluoride.
The optimal level for fluoride in drinking water, as defined by the U.S. Department of Health and Human Services, is 0.7 mg/L (milligrams per liter). At this level, adding fluoride helps prevent dental decay and strengthens teeth for people of all ages.
However, excessive consumption of fluoride can lead to cosmetic dental problems, especially for children younger than age 10, and can increase the likelihood of developing bone diseases in severe cases.
The maximum concentration of fluoride allowed in public water systems is 4.0 mg/L and is enforced by the EPA in order to prevent the development of skeletal fluorosis, a condition which causes painful damage to bones and joints. The EPA also has a non-enforceable secondary standard for fluoride of 2.0 mg/L, which is the concentration at which children begin to develop tooth discoloration, or fluorosis, as a result of excess exposure to fluoride.
While the EPA does not force systems to comply with the secondary standard, it requires them to notify their customers when the average water levels exceed the secondary standard. This is the message that residents of Kilmarnock received.
The drinking water supplied by the town of Kilmarnock has a fluoride concentration of 2.76 mg/L and is drawn from the Potomac and Aquai aquifers. The Potomac aquifer is the largest and deepest aquifer in eastern Virginia and is the primary source of groundwater in the area, supplying towns across the region with water rich in fluoride. The issue of high fluoride concentrations is a regional one in the Northern Neck, and last year nine out of the 10 water supply systems operated by Aqua Virginia in Lancaster and Northumberland counties also reported higher than recommended levels of fluoride.
“This has been around ever since people tapped those aquifers that basically serve that area. And those aquifers have always had fluoride, probably before we could even measure it,” said Dr. Christopher Crockett, chief environmental officer for Aqua America. “It’s just there in the ground, it’s dissolving into the aquifer, it’s been there forever.”
Due to the expense involved in removing fluoride from water, Kilmarnock town manager Tom Saunders says the town does not have plans to enhance the town’s water supply system in order to lower fluoride levels.
“From a practical standpoint it makes no sense to remove these minerals when they have absolutely no negative effects on 99% of the water that is used: washing clothes, showers and baths, flushing toilets, and car washes. The only water for which treatment might be desirable is the water that we drink or ingest: coffee, tea, baby formula, soup, and that amounts to just a couple gallons per day per connection. Removing minerals from 100% of the water pumped from the ground makes little sense when only 1% benefits,” Saunders said.
Adult teeth are not typically affected by the levels of fluoride observed in the Northern Neck, but younger children are at an increased risk of developing fluorosis. Fluorosis usually presents itself as white chalky spots on the teeth but can turn into brown spots and even create a pitting, or series of holes, in the teeth in severe cases.
“It can be problematic in the fact that the enamel’s very hard, but if there’s any penetration through a little pit or a fissure, the dentin, which is the softer, sensitive part of the tooth underneath the enamel, will get decayed very quickly,” said Dr. David Newsome, a Kilmarnock dentist. “We see what we would call Northern Neck cavities, where it’s just a little pin hole through the enamel, but when you get down through, it just blows out and creates a lot of decay.”
Fluorosis is a life-long condition once it’s contracted and, according to Dr. Newsome, treating it can present an expensive challenge.
“The teeth aren’t attractive and they’re not receptive to bonding because they’re very hard and malformed and all of our bonding systems, tooth color restorations or verniers that are bonded to the teeth all depend on a good enamel surface and sometimes that will make the restorations not work very well because of the fluoride,” said Dr. Newsome.
Affected teeth can be bleached or topped with crowns, but these are both costly options for fixing a largely cosmetic condition.
People concerned about their children ingesting high levels of fluoride can purchase a reverse-osmosis water purifier which attaches to their faucets at home and can remove fluoride and other harmful minerals from the water. Common activated carbon filters like Britta or PUR, which improve the taste and smell of water, do not remove fluoride. Another option is to use bottled water for drinking and cooking.