Mercury

Where It Comes From in New Mexico

In New Mexico, mercury enters water from both natural geology and human activities ¹. Naturally occurring traces of mercury are found in the rocks of the Ladron and Magdalena Mountains, and weather over time can wash these minerals into local waters ¹. Human activities have also left a lasting impact; historic silver and gold mining used extraction processes that released inorganic mercury into the environment ¹. Today, emissions from coal-fired power plants can also release mercury into the air, which is eventually washed by rain into bodies of water like Elephant Butte Lake ¹,³.

Health Concerns

Mercury is a dangerous toxin. The Environmental Protection Agency (EPA) has set a strict legal safety limit for inorganic mercury in drinking water at 0.002 milligrams per liter, which is equivalent to 2 parts per billion ⁴. Drinking water with levels above this limit over a long period can cause kidney damage and impaired kidney function ¹,⁴. Another form of mercury, called methylmercury, is usually a concern when eating contaminated fish rather than drinking tap water, and it can severely harm the developing brains and nervous systems of fetuses and infants ¹,⁵.

How Climate Change Exacerbates Exposure Risk

Climate change is bringing more extreme weather to New Mexico, including prolonged droughts, larger and more frequent wildfires, and intense storms ⁹, ¹⁰. These changing weather patterns can directly increase the risk of mercury washing into our water systems ⁹. For example, when high-intensity wildfires destroy forest vegetation, the bare soil is left highly vulnerable to erosion ¹⁰. Subsequent heavy rains and floods can then cause extreme debris flows, washing massive amounts of sediment and ash into local rivers and streams ¹⁰. Because mercury has been left behind in the environment from New Mexico's long history of silver and gold mining, as well as at various contaminated Superfund sites, more intense and frequent storms can sweep these toxic metals out of the soil and into our waterways and groundwater ¹,⁹.

How to Mitigate Exposure Risk

The vast majority of New Mexico's public water systems successfully meet strict safety standards for mercury. In fact, the state's 2023 Annual Compliance Report confirmed zero verified mercury violations statewide for that year ⁶. However, if you get your water from a private well, the government does not test or regulate it, so you are responsible for ensuring it is safe ⁷.

• Look out for signs: Because you cannot see, taste, or smell mercury, you cannot rely on your senses to warn you of contamination ².

• Test your water: Having your well water tested by a certified laboratory is the only way to know if it contains mercury ⁷. The New Mexico Environment Department periodically hosts free local "Water Fairs" where private well owners can get their water tested and learn about common pollutants ¹.

• Filter your water: If testing shows high levels of mercury, you can install specialized water treatment systems in your home. Reverse Osmosis (RO) systems are considered one of the most effective options and can remove over 90% of inorganic mercury from drinking water ¹,⁷,⁸. Other helpful systems include distillation, which boils the water and collects the clean steam, and activated carbon filters ¹,⁸.