A wide variety of chemicals used in household goods ranging from furniture to fabrics might be effective at preventing fires, but new types of “replacement” flame retardants are being released into the environment and their long term consequences are still unknown, according to a scientist who will deliver a guest lecture here Thursday.

“It is a conundrum,” said Robert Letcher, a senior research scientist and adjunct professor at Carleton University. “It’s just a fact of living in a modern society. It’s not to say that all these chemicals are toxic, but at this point we just don’t know what they’re capable of doing if they get into the environment.”

A former assistant professor in the University of Windsor’s chemistry department who worked at the Great Lakes Institute for Environmental Research in the early 2000s, Dr. Letcher will deliver a keynote lecture called Emerging Flame Retardants in the Great Lakes Birds: Linking Source Pathways, Exposure, Fate and Effects Using an Adverse Outcome Framework, at GLIER’s annual research colloquium this Thursday.

A two-day year-end event, the colloquium is a showcase of GLIER's up-and-coming young scientists, many who study how aquatic ecosystems like the Great Lakes respond to such stressors as exotic invasive species, toxic chemicals, habitat alteration, climate change, and overexploitation, all which jeopardize clean water, healthy fisheries, and sustainable agriculture.

Letcher’s lecture will focus on environmentally “emerging” flame retardant chemicals that are mixed in with plastics and other materials used to make everyday items like telephones, televisions and furniture. Known in the industry as polybrominated diphenyl ethers, or PBDEs, these older brominated flame retardant formulations were proven to be toxic, persistent and bioaccumulative, and many were either carcinogenic or had endocrine disrupting properties, he said.

Although recent and limited, scientific evidence is beginning to show these “emerging” chemicals are entering the environment, either by being released in to the atmosphere, or leaching into the ground water when they’re disposed of landfills, Letcher said. Over the last 15 years, industry has developed new replacement flame retardant chemicals and formulations, which tend to be heavier molecules with more bromine atoms, and include PBDE-plus type chemicals. Of about 75 new known brominated flame retardants currently in use, a weight of evidence is showing that many are chemically and environmentally unstable despite industry claims to the contrary, he said.

“It’s these substances that are emerging in the environment, and we’re just beginning to understand if they’re present in the environment and whether they will pose any harm to exposed animals and humans,” he said.

Letcher will deliver his talk on April 3 at 9 a.m. in Room 250 at GLIER, located at 2990 Riverside West.

His lecture will kick off two days of student research presentations, and for the colloquium’s first time, students from visiting schools like the University of Guelph, McGill, and the University of Waterloo will also deliver talks on their work.