Per-and Polyfluorinated Substances – PFAS

Per-and Polyfluoroalkyl Substances (PFAS) – “forever chemicals”


PFAS are widely used, long lasting chemicals, components of which break down very slowly over time. They can contaminate water bodies through direct discharge, runoff, or air deposition. Because of their widespread use and persistence in the environment, PFAS are found in water, air, soil, and living organisms at low levels everywhere in the world. There are thousands of PFAS chemicals that are found in many different consumer and industrial products. This makes it challenging to study and assess the potential human health and environmental risks.

In 2021, ORSANCO completed a baseline study of ambient levels of PFAS in the Ohio River surface water. The study analyzed for 28 PFAS at 20 sampling locations at higher and lower  flow conditions. Results of the study were based on “point in time” or instantaneous sampling events to help inform state and federal agencies, water utilities, and other interested parties on the status of PFAS in the river, and provide a basic understanding to evaluate potential need for future PFAS monitoring of the Ohio River. Results from both rounds of sampling indicated the presence of select PFAS analytes at, or above trace levels. Twelve of 28 PFAS were detected in the Ohio River, six of which had quantifiable concentrations at one or more sites, with PFOA, PFOS, GenX, and PFBA being most notable. More detailed results can be viewed in the report online.

In 2023, ORSANCO completed a broad scan survey that tested for 97 pollution control standards- priority pollutants and 40 PFAS as emerging contaminants of concern in each of two rounds at three locations along the Ohio River (Parkersburg river mile (ORM 193), Louisville (ORM 633), and Paducah (ORM 912)). PFAS concentrations were generally lower in the broad scan survey than the more extensive 2021 ambient study.  A report of the broad scan survey will be available on ORSANCO’s website later this year.

Additionally, ORSANCO monitors for a suite of 35 PFAS in fish tissue annually. Based on the Great Lakes Consortium recommended criteria for PFOS, only 5 of the 35 fish tissue composites ORSANCO has collected to date would result in a more restrictive consumption advisory than currently listed for Polycholrinated biphenyls (PCBs) and Mercury contamination. The concentrations in those 5 composites would be associated with the lowest restriction level of “One Meal per Week.”

ORSANCO will continue to monitor the Ohio River for the presence of PFAS and keep federal agencies, water utilities, and the public informed of their findings. For more information on PFAS, see up to date resources listed on the Environmental Protection Agency’s (EPA) website.

Read more about our member state-specific PFAS updates: