New Hampshire's groundwater contains a number of contaminants that are not good for our health. Some of these contaminants are man-made, such as MtBE, which was used as an additive in gasoline and may take many decades to clean up. Others, such as arsenic, are naturally occurring, and have health effects that are every bit as concerning as those associated with exposure to man-made substances.
Arsenic is the number one naturally occurring chemical of environmental health concern in the United States and worldwide according to the Dartmouth Toxic Metals Superfund Research Program. Even at low levels, arsenic is associated with an increased risk of a variety of illnesses including cancers, cardiovascular disease, diabetes and other non-cancer related diseases. As the New Hampshire Department of Environmental Services celebrates its 25th anniversary, we are confident that as a result of advances in toxicology, epidemiology, and oversight of public water systems, many New Hampshire residents are drinking water with much lower levels of arsenic as compared to 25 years ago.
Arsenic occurs naturally in many parts of the world, including New Hampshire. In fact, arsenic was mined commercially in New Hampshire during the 1800s. Most arsenic in New Hampshire well water is naturally occurring. Arsenic contamination has also occurred as a result of human activities such as apple orchard spraying and coal ash disposal. Arsenic no doubt has been consumed at varying levels by a large portion of the state's population ever since Granite Staters have drilled wells into bedrock for their water supply. Arsenic has no smell, taste or color when dissolved in water, even at high concentrations. It is an example of an environmental contaminant that can easily go unnoticed because its presence can only be detected by laboratory analysis.
From 1975 until 2001, the federal limit for arsenic in water supplied by public water systems was 50 parts per billion, because the health effects of exposure to lower concentrations was not recognized. Based on an exhaustive review of the new information about arsenic's health effects, in January 2001 EPA established a goal of zero arsenic in drinking water. At the same time, EPA adopted an enforceable limit of 10 parts per billion (ppb) based on balancing treatment costs and public health benefits.
DES, which oversees public water systems to ensure compliance with federal and state standards, performed extensive outreach to inform and assist public water systems in achieving the new 10 ppb standard. All "non-transient" public water systems were given five years to evaluate and implement compliance options. Neither private wells nor transient public water systems — such as restaurants and hotels that serve fewer than 25 of the same people each day — are required to comply with the arsenic standard.
About 200 of New Hampshire's 1,200 non-transient public water systems have had at least one detection of 10 ppb or greater of arsenic. Of those, 95 percent have implemented treatment or drilled new wells to comply with the standard, and DES is pursuing enforcement actions against the remaining systems. One cost-effective option, especially for private wells and very small systems such as schools and businesses, is point-of-use treatment, because the main concern with the arsenic levels found in New Hampshire is from drinking and cooking, rather than from bathing or washing hands. Ongoing technical assistance provided by DES since the adoption of the new standard has been key to achieving and maintaining water system compliance and protection against this contaminant. In fact, New Hampshire is recognized as a leader in drinking water arsenic compliance solutions by the EPA.
Research into the health effects of arsenic in drinking water is ongoing and DES actively collaborates with Dartmouth's toxic metals program, the U.S. Geological Survey, and other partners through the "Arsenic Consortium" to increase awareness and reduce arsenic exposure through untreated or inadequately treated drinking water from private wells.
DES also provides outreach through other groups such as local health officers and the medical community to inform and encourage New Hampshire residents who rely on private wells to test their well water. The U.S. Geological Survey estimates that one in five private wells in New Hampshire has water with 10 ppb or more of arsenic.
Regardless of whether it was 25 years ago, today, or 25 years from now, due to our state's geology, arsenic in drinking water has been and will always be a risk for New Hampshire's residents, but proven, cost-effective solutions, combined with the vigilance of regular monitoring, can protect us from the health hazards of this contaminant.
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Thomas S. Burack is the commissioner of the New Hampshire Department of Environmental Services. For information about DES's private well testing recommendations, please contact us at firstname.lastname@example.org or call 603-271-2513.