CINCINNATI -- A potentially dangerous chemical no longer used in manufacturing is still showing up in above-average amounts in Tri-State residents' bodies, likely because of the water we drink.
Residents of the Mid-Ohio River Valley, which stretches from Huntington, West Virginia, to Evansville, Indiana, had higher than normal levels of perfluorooctanoic acid (PFOA) based on blood samples collected over a 22-year span, according to new research from the University of Cincinnati .
PFOA can be found as a residual impurity in some paper coatings used on containers for processed food.
"Because the elimination time could be several years, it is hard to determine what impact these environmental exposures may have on our health and children’s health,” said Susan Pinney, professor in the Department of Environmental Health at the UC College of Medicine. "These data from the 1990s demonstrate that that the contaminants have been in our water a long time, at unchecked levels, before anyone was paying attention to it.”
Pinney points out that the primary concern with PFOA is that it takes a very long time to leave the human body, and studies indicate that exposure to PFOA over certain levels may result in adverse health effects, including developmental effects, liver and tissue damage and immune and thyroid impacts.
The study, appearing in the latest publication of Environmental Pollution , looked at levels of PFOA and 10 other per- and polyfluoroalkyl substances (PFAS) in 931 Mid-Ohio River Valley residents, testing blood serum samples collected between 1991 and 2013, to determine whether the Ohio River and Ohio River Aquifer were sources of exposure.
Ohio River PFOA concentrations downstream were elevated, suggesting Mid-Ohio River Valley residents were exposed through drinking water, primarily contaminated by industrial discharges as far as 413 miles upstream. Industrial discharges of PFOA to the Ohio River, contaminating water systems near Parkersburg, West Virginia, were previously associated with nearby residents’ serum PFOA concentrations above U.S. general population medians.
An earlier study looking at samples from girls and young women from Northern Kentucky showed that about half of the samples from the girls were much higher than the national average for U.S. children (the 95th percentile) concentration.
The Northern Kentucky Water department has since then implemented the use of granular activated carbon filtration at their plants to meet new federal regulations, and Cincinnati Water Works used the study’s findings to check their treatment regulations and filtration usage.
"Where GAC has been used, the blood level concentration of PFOA was decreased significantly (by as much as 60 percent),” said co-author Robert Herrick, a UC doctoral student in the Department of Environmental Health.
Nearly all of the samples tested positive for some level of PFOA (99.9 percent), but 47 percent of the samples had PFOA levels higher than the 95th national percentile.
The study additionally looked at information about municipal water distribution systems and the zones that were serviced by each of the water treatment plants.
"We conducted statistical analyses to determine if factors such as location and years of residence, drinking water source and breastfeeding were predictors of the person’s serum PFC concentration,” Herrick said.
PFCs have had wide consumer use and industrial applications. They are surfactants used in fire-fighting foams and in the manufacture of stain and water resistant coatings, on cookware, furniture and carpeting. As a byproduct of commercial production, PFCs/PFOA are released into the environment and, although no longer used in manufacturing in the U.S., are considered persistent in the environment.
Pinney cites projects like this one as having the translational potential to make improvements in public health.
"Studies like these provide evidence to support changes in water treatment practices,” she said.