WHAT IS ARSENIC?
Arsenic is a naturally occurring contaminant in some groundwater in Massachusetts, most frequently in the central part of the state. It can also be a by-product of some agricultural and industrial activities. Drinking water from bedrock wells, also called drilled or artesian wells, gravel-developed wells, and less frequently, from shallow or dug wells may contain arsenic. Arsenic has no smell, taste, or color when dissolved in water, even in high concentrations, so only laboratory analysis can detect its presence and concentration.
DOES ARSENIC IN DRINKING WATER AFFECT MY HEALTH?
Arsenic ingestion can result in both acute (short-term) and chronic (long-term) health effects. Acute effects can include nausea, vomiting and cardiovascular effects, while chronic effects can include changes in skin coloration, skin thickening, and an increased risk of certain types of cancer. Arsenic is not easily absorbed through the skin and does not evaporate into the air, so activities like hand washing, bathing, and showering in water that contains arsenic at levels up to 500 parts per billion (ppb), which is 50 times higher than the drinking water standard, does not pose a known risk to human health.
WHAT IS BEING DONE TO ELIMINATE ARSENIC FROM OUR DRINKING WATER?
In 2001, the Environmental Protection Agency (EPA) reduced the Maximum Contaminant Level (MCL) for arsenic from 50 ppb down to 10 ppb. When present in the raw groundwater, arsenic is removed via filtration at our water treatment plants to levels below the MCL. The most recent results for treated water entering our distribution system are listed in the table below.
| Date | Source | Concentration (mg/L) |
| 04/24/2024 | Central Acton WTP | ND |
| 06/10/2024 | North Acton WTP | ND |
| 04/26/2023 | South Acton WTP | ND |
