Located in Texas’ Lower Rio Grande Valley, the Arroyo Colorado watershed is quickly urbanizing and growing in population.
Research conducted by the Texas Water Resources Institute (TWRI) and Texas A&M University scientists analyzed water samples collected in the Arroyo Colorado watershed and found levels of per- and polyfluoroalkyl substances, or PFAS. Published earlier this year in the Journal of Contemporary Water Research and Education, the study is the first analysis of its kind for the watershed.
PFAS are manufactured chemicals made up of carbon-fluorine bonded molecules. More than 15,000 different types of PFAS chemicals exist.
These chemicals have been used in products since the mid-20th century, including in fire-extinguishing foam, non-stick cookware, and other items, eventually contaminating water supplies and agricultural sources.
How prevalent are PFAS chemicals?
Yina Liu, Ph.D., an assistant professor in the Department of Oceanography at Texas A&M and a 2022 TWRI Faculty Fellow, led this study, along with coauthors Lucas Gregory, Ph.D., TWRI associate director, and Allen Berthold, Ph.D., TWRI associate director.
“We used 15 samples taken from the Arroyo Colorado, as well as 6 samples from irrigation canals, 7 from stormwater and wastewater retention ponds, and 2 from drinking water to test for levels of PFAS,” Liu said.
Liu conducted the testing at her lab at Texas A&M. After testing, 29 out of the 30 samples revealed various levels and types of PFAS, she said.
The single sample without measurable traces was likely influenced by specific factors. “We believe that tidal movements at that location may have diluted the chemical,” Liu said.
Notably, short-chain PFAS were observed in the two municipal water samples, but they were below the current U.S. EPA regulation limits or are not currently regulated.
Many surface water samples collected contained PFAS at various concentrations and types, she said These samples provided significant insight into understanding the impacts of PFAS on water resources.
Outcomes and future research
Liu said this study also sheds light on predicting, measuring and understanding the presence of PFAS in rapidly urbanizing areas.
This research not only gives insights into the Arroyo Colorado watershed, but also into PFAS-related impacts globally, she said.
TWRI is continuing to fund, collaborate on and support various research projects studying PFAS chemicals and their effects on agriculture, water and people.
