SOCORRO, N.M., September 3, 2002 -- The New Mexico Bureau of Geology and Mineral Resources (NMBGMR) recently published the summer issue of its free newsletter New Mexico EARTH MATTERS. The focus of this issue is arsenic in New Mexico's drinking water.

"Arsenic is a naturally occurring element found in many of the rocks and minerals that make up the Earth's crust," the article states. In New Mexico, one of the most common rocks containing arsenic is pyrite or "fool's gold." Also, silica-rich volcanic rocks in the Jemez Mountains and some sandstones and mudstones that underlie the Albuquerque area contain high amounts of arsenic. Rocks that contain arsenic can contribute the element to surface and ground water.

The arsenic content of the Rio Grande varies with geographic location. In the Rio Grande near the San Felipe Pueblo, the water contains about two parts per billion (ppb) arsenic, but by the time the river reaches the Isleta Pueblo, the arsenic concentration has reached four ppb.

Arsenic in ground water is a more common problem in New Mexico. Nationwide, 5.5 percent of municipalities would have to treat drinking water to meet new EPA arsenic-in-drinking water standard of 10 ppb. In New Mexico that number is closer to 20 percent, and 93 percent of these municipalities are small communities that cannot afford the cost associated with meeting these new standards. For the average New Mexican, meeting these standards could increase the cost of water by $50-$90 per month.

High levels of arsenic in drinking water (more than 400 ppb) can cause cancer as well as other health problems, but the long-term effects of low levels of arsenic in drinking water on human health are still uncertain. Given the uncertainties surrounding this issue, the article raises a final question for the reader to consider: Is it better for New Mexico to spend its money on meeting these new arsenic standards, or would we be better off spending the money on more critical health issues that face us today? While the article doesn't specifically answer this question, it does point out the importance of re-evaluating the issue of low levels of arsenic in drinking water, especially as new information becomes available.

Another article in this issue concerns the changes that have occurred in the NMBGMR as its 75th anniversary approaches. Originally the main focus of this organization was geologic mapping and the description of hard-rock mining prospects. Through the years, that has changed to additionally include issues ranging from coal and petroleum development to water supply. Education of the general public is another important goal for the NMBGMR. Non-technical publications like New Mexico EARTH MATTERS are published to provide a balanced and comprehensive look at geologic and hydrologic issues in New Mexico.

New Mexico EARTH MATTERS is distributed twice a year, free of charge, by NMBGMR, a service division of New Mexico Tech. For more information about this publication or any other NMBGMR publications, write to the Bureau Publication Office, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801, or call (505) 835-5410, or visit the Bureau's website at http://geoinfo.nmt.edu.