Studies by researchers at the Research Institute of the McGill University Health Centre confirm what many people have always suspected. Environmental contaminants can interfere with fetal and immune system development. These studies, part of a federal research initiative into toxic substances, show that exposure to certain toxicants during pregnancy has effects on the fetus that persist into adulthood to affect reproductive ability.
The MUHC researchers conducted two studies under the program. The first looked at the effect on fetal development of ingesting a mixture of organic pollutants found in industrial chemicals such as paints, cleaning solvents, and pesticides. The use of some of these products was banned in Canada in the 1980's, but they are still present in high concentrations in the environment and are evident in the diet of Baffin Island Inuit. "We chose to study the mixture of pollutants found in the diet of the Inuit because these people are exposed to higher than average concentrations of these chemicals, including organochlorines," says MUHC researcher and faculty member of Department of Pharmacology and Therapeutics at McGill University, Bernard Robaire. "We looked at the reproductive system because of the potential consequences on fertility and subsequent generations."
Robaire and his collaborators from McGill University, Health Canada and INRS-Armand Frappier, studied pregnant rats that were fed varying doses of organochlorines. The results showed that rat pups that were exposed to these chemicals in utero "had adverse effects on postnatal growth and on the development of the testes and ovaries," says Robaire.
The second study presented by MUHC researchers looked at the contamination of the Canadian food supply with a compound used in marine paint, tributyltin (TBT). "Remarkably little is known about how this chemical affects human health," says Professor Barbara Hales of the Department of Pharmacology and Therapeutics at McGill University, a co-investigator of this study.
Hales and colleagues from McGill University, Health Canada, and INRS-Armand Frappier initially demonstrated that several fresh and prepared seafoods were found to contain TBT. They then fed pregnant rats varying quantities of TBT and analyzed the immune and reproductive systems of their pups. Their results showed that the pups had over-active immune systems and abnormal development of their reproductive systems. "These results indicate that the adverse effects of exposure to TBT during gestation last well into adulthood and raise serious concerns about the safety of consuming foods that contain TBT," suggests Hales.
Both Hales and Robaire agree that further studies are needed to fully understand the long-term effects of these environmental pollutants. "In order to develop appropriate solutions we need to continue this type of research," says Robaire.
The Toxic Substances Research Initiative was established by the federal government in 1998 with the mandate to promote research into the links between toxic substances, environmental damage and human health; a major objective of this program was to encourage government and university scientists to enter into active collaborations. This program was a three-year initiative of the federal departments of Health Canada and Environment Canada.