It's been a little over two months since the notices started hitting East Providence mailboxes regarding a violation in our water supply. The notice, couched in a bunch of required legalese, notified residents of elevated levels of Trihalomethanes (TTHMs) which is a disinfectant byproduct (DBP). TTHMs are formed when disinfectants such as chlorine react to organic matter, like grass, that enters the water supply from the source (Scituate Reservoir).
City officials assured residents that the water was safe to drink, citing that exposure over a period of years is required to cause health effects and citing that only one out of four testing points were over the limit. Many residents were confused by the initial notice, the lack of immediate information on the city's website and social media pages and the actions of school officials to cover water fountains and issue bottled water. The matter was reviewed in detail at the February 20th Council meeting.
Recently, residents have been complaining of rashes, itching and skin irritation after showering. We reached out to Water Superintendent Jim Marvel with questions on the dermatological effects of TTHMs, Marvel responded "The water is safe... If the water were considered unsafe for contact, the health department would have required a much different notice."
Marvel's position is supported by research, including a study into TTHMs by the World Health Organization (WHO). Which cited only bodily absorption as an effect of showering or bathing in water with elevated TTHMs and even then in higher levels than East Providence. Even increased risk of cancer in humans, over an extended period of exposure is not completely clear as it is often difficult to attribute causation in test groups.
In addition to Mr. Marvel, we reached out to officials at the Rhode Island Department of Health (RIDOH) and the Environmental Protection Agency (EPA). The EPA's press office is still working on a response to our inquiry, however an official from RIDOH did respond as follows. "No alternative source of water is necessary. TTHM is considered a chronic contaminant. Some people who regularly drink water containing TTHM at very high concentrations over many years may experience problems with their liver, kidneys, or central nervous system. But these are concentrations that are much higher than what was measured in East Providence."
At the February 20th meeting, Marvel did cite the potential for one more quarterly violation before a remedy takes hold in August. TTHMs are generally higher in warmer weather but the city has taken steps as outlined by Marvel including a new treatment tank and, by August, an aeration system on that treatment tank. The source of the issue, as Marvel explained is the antiquated treatment process that the Providence Water Supply Board uses for treatment in which chlorine is added as the first step prior to the removal of organic materials. More modern systems introduce chlorine at the end of source treatment.
So what could be the source of reported rashes and itching? Winter is notorious for dry skin it is also possible for benign 'hard water' conditions to also cause itching. Further study beyond incidental reports would be needed to tell more.
If you are still concerned about TTHM levels, many consumer water filters can remove them. See the Environmental Working Group's water filter guide to see which filters will remove TTHMs from drinking water.