A scientist at the University of Massachusetts Amherst recently received a grant to study the health effects of two perflourinated chemicals — PFOS and its recent replacement chemical. Given drinking water contamination issues in places like Newburgh and Rensselaer County, WAMC’s Hudson Valley Bureau Chief Allison Dunne spoke with the grantee about what she and her colleagues hope to accomplish.
Environmental health scientist Alicia Timme-Laragy received the $1.9 million grant from the National Institute of Environmental Health Sciences to study the health effects of the two environmental pollutants. She and her colleagues will assess the effects of the toxicity of PFOS (Perfluorooctane Sulfonate) and its replacement chemical PFBS (Perfluorobutane Sulfonate) on three species of embryos. The idea is to look at pre-conception exposure.
“The mother is exposed to all of these contaminants in the environment and, during the meantime, she’s, her body’s doing the normal things that a woman’s body would do in terms of getting an egg ready to ovulate and these chemicals can affect that process,” says Timme-Laragy. “And so that’s what we’re trying to look at is how these perflourinated chemicals are interacting with the nutrients that are being put into that egg, before conception even occurs.”
There are a number of emerging contaminants but Timme-Laragy says she chose to study PFOS and PFBS because of previous research on PFOS.
“We have done some work actually doing some developmental studies so, along the same vein, looking at this concept of developmental origins of disease and we were really startled to find in a paper that we published earlier this year that exposure to PFOS pretty dramatically affected the way that the pancreas is formed. So we were really intrigued by this. And there are other reports out there about PFOS being transferred from the mother into the egg,” Timme-Laragy says. “And so part of what we’re trying to figure out is are these effects on the developing pancreas, which is your major nutrient-sensing organ, and is related to metabolic syndrome and diabetes and all of these health effects, is that disruption coming from exposure to PFOS itself or is it more of a nutrient alteration. So are the building blocks for a developing organism, are those being kind of hijacked by these perflourinated compounds that are then being deposited into the egg.”
She and her colleagues will assess effects on nutrient deposition in the embryos of three different organisms, with exposure before conception, as well as consequences for later-life metabolic dysfuntion. Timme-Laragy says if the same thing occurs in the fish, the fly and the worm, it gives scientists some confidence that there is relevance for human health.
“So the problem with trying to address these sorts of questions in humans is that we are exposed to a soup of chemicals every day and it’s very difficult to pinpoint a causal agent when you’re being exposed to so many things at once. In the laboratory, we can really narrow down and look very specifically, do we see these sorts of effects resulting from this specific chemical exposure, and when did that exposure occur, at what point during development is that most important,” says Timme-Laragy. “So we’re using the zebrafish which, it might sound strange to be using a fish to study human health, but we can do this because there’s so much in common between those early life stages between humans and fish. And by adding in these parallel studies that my colleagues are conducting using the roundworm and fruit fly, we’re really able to create a really powerful model taking advantage of what we know about evolution. And if we see these conserved effects happening from three different organisms, that makes a really strong case that, if we identify certain genes that are being changed in our model system, we can make a pretty good case that this would also be happening in humans as well.”
The study will last for five years.
“What we try to do is we look at what the concentrations are out in the environment. So we read the literature and look at what people are reporting that they’re finding in drinking water systems. We look at the NHANES [National Health and Nutrition Examination Survey] database and we look at what concentrations are being reported to be found in people,” says Timme-Laragy. “We try to make sure that the concentrations of chemical that we’re using in the laboratory are going to be meaningful for what people would be exposed to.”
Timme-Laragy says the stain-repellent chemical PFOS used in making non-stick coatings, for example, is toxic and very stable in the environment. In the case of Newburgh, officials say PFOS came from the historic use of firefighting foam, a type of foam no longer used. The half-life of PFOS in the human body is more than five years and it may persist in the environment for decades. Timme-Laragy also says exposure is associated with higher cancer rates, diabetes and other diseases. In recent years, PFOS has been replaced by PFBS, which is believed to persist for less time in the body and the environment.
“Part of what we’re trying to figure out is whether or not this replacement perflourinated compound, PFBS, is going to be more or less toxic compared to what we know about PFOS,” Timme-Laragy says.
Zebrafish embryos are transparent, so scientists can see the embryo developing in real time under a microscope and, says Timme-Laragy, watch it progress, which is relevant to looking at the interaction between nutrients and the chemical. Timme-Laragy says one of their hypotheses is that the toxic substance is directly affecting the embryos’ ability to use food.