PFAS chemicals have been detected in groundwater and surface water resources across the state of New Mexico, with urban areas being the most significant contributor, according to two recent studies by the U.S. Geological Survey done in cooperation with New Mexico Environment Department (NMED).
Frequently called ‘forever chemicals,’ PFAS are a group of synthetic chemicals used in a wide variety of common items, such as firefighting foams, non-stick cookware and fast-food packaging. PFAS may lead to adverse human health risks, according to the U.S. Environmental Protection Agency. These chemicals are found in many places across the nation and can stay in the environment for a long time, making them a unique water-quality concern.
The initial statewide study sampled 117 groundwater wells and 18 surface water sites across New Mexico between August 2020 and October 2021. PFAS were detected in all major rivers of New Mexico with highest concentrations from sites downstream of urban areas. Total PFAS concentrations from surface water samples ranged from 1.0 to 155.4 nanograms per liter. PFAS were detected at 27 groundwater sites, though no results exceeded the EPA's 2016 health advisory limit.
"The comprehensive survey of New Mexico's major rivers and evaluation of groundwater quality across the state is critical in helping NMED protect these valuable resources," said Andy Jochems, Source Water Protection Team Lead from the New Mexico Environment Department. "The science provided by the USGS helps us make informed decisions about our drinking water resources into the future.
Total PFAS concentrations from surface water samples ranged from 1.0 to 155.4 nanograms per liter. PFAS were detected at 27 groundwater sites, though no results exceeded the EPA's 2016 health advisory limit
After discovering that populated areas contribute the highest PFAS levels to surface water statewide, a follow-up USGS study was conducted to examine the water quality in the Rio Grande as it flows through Albuquerque, the largest city in New Mexico. In the second recently published article, scientists found that the urban area significantly contributes to the levels of PFAS in the Rio Grande.
USGS scientists collected water samples from upstream and downstream of the urban area of Albuquerque, as well as treated water released from the wastewater treatment plant. The results showed that PFAS levels were approximately 10 times higher in the river downstream of the urban area compared to upstream locations.
"Our study highlights the complex nature of chemicals associated with urban areas and their impact on river systems," said Kimberly Beisner, USGS hydrologist and lead author of the studies. "The data show that urban areas can be a major contributor of PFAS to rivers, with constantly changing concentrations due to wastewater discharge, stormwater runoff and other sources."
PFAS levels changed over the 24 hours the USGS team took samples from the Rio Grande. Some of the changes seemed to be from treated wastewater being released into the river. Other changes may have been from stormwater washing PFAS off streets and other surfaces in the urban area when it rained.
The researchers also utilized innovative sampling techniques, including passive samplers that provide time-averaged PFAS concentrations over several weeks. This approach helped identify PFAS that may have been missed by traditional collection methods.
