A lecture on campus today will examine the work of an ecotoxicologist to have the use of perfluorooctane sulfonate (PFOS) banned and develop a commercially viable substitute for the chemical.

John Giesy, professor in the Department of Veterinary Biomedical Sciences and Toxicology Centre at the University of Saskatchewan, will deliver his free public talk, entitled “Toxicological Evaluation of Perflurooctan in the Environment: Anatomy of an Environmental Issue,” at 4:30 p.m. November 4 in Ambassador Auditorium, CAW Student Centre.

The event is part of the Royal Society of Canada’s Romanowski Lecture Series. Giesy is a fellow of the society as well as Canada Research Chair in Environmental Toxicology.

Perfluorinated chemicals have been widely detected in the environment and in organisms, including in such remote areas of the world as the Canadian Arctic. PFOS takes a very long time to break down in the environment and can “bioaccumulate,” or build up in the food chain. A number of related chemicals, referred to as “PFOS precursors” can transform or degrade into PFOS in the environment.

PFOS, its salts and its precursors were used as water, oil, soil and grease repellents for carpets, fabric and upholstery and food packaging, and as surfactants in specialized applications such as fire-fighting foams, aviation hydraulic fluids, and fume suppressants for metal plating.

PFOS was not historically thought to be particularly harmful to humans until Giesy developed more sensitive analytical methods to assess its environmental impact. His work eventually resulted in a Canadian ban on the use of 87 associated chemicals harmful to the environment. At the same time, he developed a suitable PFOS substitute that did not have the same negative impact but allowed the continued commercial availability of products which had previously used PFOS.