HUMAN HEALTH EFFECTS ASSOCIATED WITH PCB EXPOSURE

Introduction | Health Effects of PCBs | Exposure to PCBs in Great Lakes | Health Effects in Great Lakes Areas of Concern

Health Effects in Great Lakes Areas of Concern

The GLHEP compiled statistics for health concerns in each of the 17 “areas of concern” in the Ontario part of the Great Lakes basin. These reports contained data on human health outcomes “selected on the basis that they may be linked to exposure to environmental contaminants.”¹³ The mortality data used in the reports were provided by Statistics Canada. The morbidity and birth weight data were compiled from hospital separations data. Cancer data were compiled from the Ontario Cancer Treatment and Research Foundation. Congenital anomalies data were gathered from the Canadian Congenital Anomaly Surveillance System. The data cover the period from 1986-1992. The reports were released to the public in October 1999.

The data for each area of concern were compared with data for the whole of Ontario to determine whether there were statistically significant differences for heath effects in each area of concern from Ontario as a whole. The significance of the ratios was determined using the Poisson Ratio Test using 95% and 99% confidence intervals.

Each report presents tables showing the health effects for which there were significant differences. The reports do not, however, make any conclusions on the causes of these differences. Appendix A in each report provides brief descriptions of “some possible causes for the selected health outcomes.” These causes include occupational exposures, heredity, lifestyle factors (smoking, drinking, diet and exercise), and specific environmental contaminants.

Health Canada discouraged people from making conclusions about causes based on its reports. The cover letter sent to each person that they sent the reports to said:

It is important to note that the data cannot show a causal relationship between the environment and specific health outcomes…. The extent to which environment can be a factor still remains largely unknown. Thus the purpose of this initiative was to provide ‘raw’ data for experts in the field to work with in furthering their understanding. Any explanation of these data requires further investigation.¹⁴

As a result, the reports do not really help us in making conclusions about the effects that PCBs in areas of concern are having on the health of people in those communities. Environment Canada has said that it is doing assessments in each area of concern to determine any possible connection between these health effects and environmental conditions in the areas of concern. Environment Canada has not given any time-line for the completion and release of this work.

The author reviewed the Health Canada reports to determine the extent to which the health effects that Health Canada says can be the result of PCB exposure show up in the reports. The author only used data when the Health Canada reports said that the data were at a significantly higher level than Ontario as a whole at a confidence level of 99%. The three most significant correlations were the following:

• Other Metabolic Disorders and Immunity Disorders: Significantly higher in 8 of 17 areas of concern (Collingwood, Cornwall, Detroit River, Jackfish Bay, Niagara River, St. Clair River, St. Mary’s River, and Spanish River).

• Disorders of Thyroid Gland: Significantly higher in 7 of 17 areas of concern (Collingwood, Cornwall, Detroit River, Jackfish Bay, St. Clair River, St. Mary’s River, and Toronto).

• Early or Threatened Labour: Significantly higher in 7 of 17 areas of concern (Bay of Quinte, Collingwood, Cornwall, Niagara River, St. Clair River, Severn Sound, and Spanish River).

¹³ Great Lakes Health Effects Program, Detroit River Area of Concern: Health Data and statistics for the Population of Windsor and Region (1986-1992), 1998, p. 1.

¹⁴ Steve Clarkson, A/Director, Bureau of Chemical Hazards, Health Protection Branch, Health Canada, Letter RE: Health Statistics Reports for Great Lakes Areas of Concern, October 13, 1999.