Mid-Ohio Valley teenagers who were exposed to DuPont Co.’s C8 pollution experienced a four- to six-month delay in puberty, according to a new study that adds to the growing concerns about potential health effects of chemicals that have been widely used in nonstick and stain-resistant products.
Members of the C8 Science Panel based their latest report on data comparing blood levels of C8 and a related chemical called PFOS in 6,000 boys and girls with information about their hormone levels and when girls began menstrual cycles.
The three-scientist team found boys with the higher levels of PFOS and girls with a higher level of both chemicals hit puberty later.
During a news conference in Parkersburg, Science Panel member Tony Fletcher described the findings as “a clear statistical association,” but cautioned it was not yet proof that the chemicals caused the puberty delays.
Fletcher offered the Science Panel’s first real public criticism of DuPont, saying he disagreed with the company’s repeated statement that scientific studies show C8 “does not harm human health and the environment.”
“That is to me too negative a statement,” said Fletcher, a researcher from the London School of Hygiene and Tropical Medicine.
“There are a number of suggested possible associations in epidemiological studies between a number of outcomes and C8,” Fletcher said. “We can’t be sure that it’s definitely caused by C8, but that is not the same thing as saying there is no evidence of effects.”
Fletcher and two other experts are conducting one of two C8 reviews as part of a $107.6 million settlement of a lawsuit filed by residents who alleged DuPont’s Washington Works plant south of Parkersburg poisoned their water with C8.
In one effort, the C8 Health Project, residents gave blood and detailed medical histories to try to give researchers a huge database from which to consider C8’s possible impacts. In the other, the C8 Science Panel — a team agreed to by DuPont and the residents’ lawyers — is trying to determine if C8 is linked to adverse health effects.
C8 is another name for perfluorooctanoate acid, or PFOA. In West Virginia, DuPont has used C8 since the 1950s at Washington Works. C8 is a processing agent used to make Teflon and other nonstick products, oil-resistant paper packaging and stain-resistant textiles.
DuPont and other companies have reduced their emissions and agreed with the Bush administration on a voluntary phase-out of the chemical. But researchers remained concerned about a growing list of possible health effects and about the chemical’s presence in consumer products, as well as continued pollution from waste disposal practices. The Obama administration has said it is considering setting the first regulatory limits on C8.
Studies released by the Science Panel over the last two years have found C8 exposure associated with high cholesterol, high levels of body chemicals linked to hypertension and cardiovascular disease, birth defects and high blood pressure.
In releasing its report on delayed puberty, the Science panel cautioned that other factors could be at work.
For one thing, growth changes associated with puberty could lead to changes in C8 blood levels, rather than the chemical itself having any effect on age at puberty. Or, other factors could be leading to both changes in the age of puberty and chemical uptake by the body. Other possible influences, including smoking, alcohol intake, obesity and family income — which impacts a variety of health measures — were examined and ruled out as the cause.
The Science Panel findings are somewhat similar to those of another study published last week in the peer-reviewed journal Environment International. While that study found no statistically significant puberty delays, it involved a sample of only 400 girls and the authors said a larger study — like that of the Science Panel — might find a link.
Another study presented last year at a scientific conference found a link between C8 and early puberty among girls, based on breast growth measurements.
Fletcher said experts on the issue tell him it’s entirely possible that C8 could cause early changes in some signs of puberty and delayed changes in others.
Scientists worry that changes in puberty timing can have implications for disease later in life, affecting things like cancer risk and skeletal maturation. Puberty timing also has implications for teen behavior issues, social difficulties and even sexual abuse risks.