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.