{"id":754,"date":"2023-10-17T14:07:00","date_gmt":"2023-10-17T14:07:00","guid":{"rendered":"https:\/\/new.www.purdue.edu\/newsroom\/?p=754"},"modified":"2024-06-28T13:02:43","modified_gmt":"2024-06-28T13:02:43","slug":"purdue-team-examines-bio-impact-of-toxic-chemical-cocktails-in-the-environment","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/newsroom\/2023\/Q4\/purdue-team-examines-bio-impact-of-toxic-chemical-cocktails-in-the-environment","title":{"rendered":"Purdue team examines bio-impact of toxic chemical cocktails in the environment"},"content":{"rendered":"

WEST LAFAYETTE, Ind. —<\/p> \n

Purdue University scientists are unraveling the complicated toxicity of a mixture of what are often called \u201cforever chemicals\u201d found in many consumer products. <\/p>\n<\/div>\n\n\n

In outdoor experiments under controlled conditions, the team found that tadpoles exposed to a common mixture of these compounds, called perfluoroalkyl and poly-fluoroalkyl substances (PFAS), suffered reduced growth as they transformed into juvenile frogs. Size at this life stage is related to the survival and reproductive success of amphibians generally, said Purdue research faculty member Tyler Hoskins. <\/p>\n\n\n\n

\u201cThere are over 5,000 of these chemicals out there that we know of, and that list continues to grow as our analytical capabilities grow,\u201d Hoskins said. A common source of these chemicals is the fire-retardant aqueous film-forming foams (AFFF) that have been used for more than 50 years to douse fuel fires at airports and military sites. But PFAS are widespread environmental contaminants that are also found in fast-food packages, nonstick coatings on cookware, cosmetics, biosolid-derived fertilizers and a broad range of manufacturing processes.<\/p>\n\n\n\n

\"A
Purdue University\u2019s Maria Sep\u00falveda currently focuses her research on the impact of \u201cforever chemicals\u201d in frogs. During her career, she has also studied ecological toxicity in marine mammals, birds, fish, alligators and turtles. (Purdue Agricultural Communications photo\/Tom Campbell)<\/figcaption><\/figure>\n\n\n\n

\u201cWe were trying to mimic what aquatic organisms would experience if they were near a site where AFFF had been historically used. Water bodies at airports and defense sites are the areas where you would expect surface water to end up with AFFF,\u201d he said. <\/p>\n\n\n\n

Hoskins and nine co-authors published their results<\/a> in a paper highlighted on the cover<\/a> of the journal Environmental Science & Technology. <\/p>\n\n\n\n

\u201cPFAS are perhaps the most persistent class of chemicals we have created since we started producing chemicals,\u201d said co-author Maria Sep\u00falveda<\/a>, professor in the Department of Forestry and Natural Resources<\/a>. \u201cStudies that look at PFAS mixtures are very critical right now, and there aren\u2019t very many because they are hard to do.\u201d <\/p>\n\n\n\n

Existing studies tend to examine PFAS at the cellular level in the laboratory rather than in whole animals. \u201cThere are very few because they\u2019re hard to do,\u201d said Sep\u00falveda, who is co-lead of the PFAS Strategic Research Team<\/a> at Purdue\u2019s Institute for a Sustainable Future<\/a>. <\/p>\n\n\n\n

A big challenge for scientists is how to sort the toxicity of various PFAS mixtures. In the field, Hoskins noted, animals become exposed to dozens of these chemicals at the same time. But when scientists run laboratory tests or outdoor studies under controlled conditions that simulate real-world environments, they often focus on exposures to three or fewer compounds. <\/p>\n\n\n\n

\u201cIt\u2019s rare to look at what\u2019s actually in the environment,\u201d Hoskins said. The team designed the study to examine the relative role of one PFAS in particular \u2014 perfluorooctane sulfonate (PFOS) \u2014 as part of a mixture with four other PFAS. <\/p>\n\n\n\n

The company that manufactured PFOS voluntarily phased it out in 2002. \u201cBut it\u2019s still the most commonly detected PFAS in the environment and in animals. It\u2019s a really important one to study,\u201d Hoskins said. <\/p>\n\n\n\n

PFOS accumulates in biological tissue more than most PFAS chemicals and also ranks among the most toxic. The researchers had hoped to resolve whether PFOS would stand out as the most toxic chemical of the mixture. Their results suggested, however, that PFOS was no more toxic than the other four PFAS in the mixture.<\/p>\n\n\n\n

The U.S. banned another class of long-lasting toxic chemicals, polychlorinated biphenyls (PCBs), in 1979. There are close to 250 types of PCBs, compared to thousands for PFAS. Scientists discovered long ago that all PCBs act in the same way.<\/p>\n\n\n\n

\"A
A new study shows that a toxic mixture of \u201cforever chemicals\u201d affects the growth of Northern Leopard frogs. (Photo provided by Matt T. Hamilton)<\/figcaption><\/figure>\n\n\n\n

\u201cWith PFAS, that\u2019s not the case,\u201d Sep\u00falveda said. \u201cThere\u2019s nothing unique that you can say, \u2018Oh, that\u2019s PFAS exposure.\u2019 There are so many different mechanisms going on that it\u2019s hard to study them because you don\u2019t know how they act.\u201d <\/p>\n\n\n\n

In studies conducted over the last five years at the whole-animal level, Sep\u00falveda\u2019s team has seen that each chemical in the tested mixtures usually has additive effects. The pervasive nature of PFAS complicates the studies. <\/p>\n\n\n\n

\u201cIf I took a blood sample from you, you\u2019re going to have a PFAS profile in your blood,\u201d Sep\u00falveda said. \u201cIt\u2019s composed of several chemicals, and not all of them have the same toxicity. You need to know how those might interact when they\u2019re together to impact toxicity.\u201d <\/p>\n\n\n\n

The chemicals are commonly found in laboratory equipment, too. This includes glassware, plasticware and even the rabbit chow they feed the frogs. <\/p>\n\n\n\n

\u201cWe found it in the tanks that leached. And worst of all, it\u2019s in the rainwater,\u201d Sep\u00falveda said. \u201cHow do you control for that? We can\u2019t keep the tanks sealed. It\u2019s a problem right now.\u201d <\/p>\n\n\n\n

The research team has follow-up studies in progress to further study mixture toxicity in insects and in aquatic community dynamics. <\/p>\n\n\n\n

\u201cAquatic organisms exist in a community, and they interact with one another,\u201d Hoskins said. \u201cWhen one member of the community gets perturbed, that can have ripple effects for other members of the community. The community-level effects of PFAS have not received much research attention.\u201d <\/p>\n\n\n\n

The team chose amphibians for this study because they have an aquatic life stage and can breed near sites affected by AFFF. <\/p>\n\n\n\n

\u201cJust like every other animal, they serve important roles in the ecosystem,\u201d Hoskins noted. They eat a lot of insects, including mosquitoes. And they serve as prey, in turn, for other animals such as herons, turtles and snakes. <\/p>\n\n\n\n

\u201cChemicals serve a lot of important purposes for us. But if we\u2019re going to put large amounts of chemicals into the environment, it\u2019s our responsibility to understand what they\u2019re doing to our health and wildlife health,\u201d Hoskins said. \u201cThat\u2019s what we\u2019re trying to do here.\u201d<\/p>\n\n\n\n

The contributors to this study include Purdue\u2019s Linda Lee<\/a>, Distinguished Professor of Environmental Chemistry in the Department of Agronomy<\/a>; Jason Hoverman<\/a>, professor in the Department of Forestry and Natural Resources; Ann Catlin, senior research scientist, Purdue Information Technology; and Youn Jeong Choi, senor analytical chemist, Department of Agronomy. They also include Wesley Flynn, now at the U.S. Geological Survey; Grace Coogan, former Purdue lab manager; Chlo\u00e9 de Perre, now at Corteva Agriscience; and Masha Modiri Gharehveran (PhD environmental engineering \u201919), now at EA Engineering, Science and Technology Inc. <\/p>\n\n\n\n

This work was funded by the U.S. Department of Defense\u2019s Strategic Environmental Research and Development Program, ER-2626.<\/p>\n","protected":false},"excerpt":{"rendered":"

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