What are the contaminant levels in Harbour Seals?
• Harbour seals are good indicators of the contaminant level in coastal food chains because they are at the top of the food chain and spend most of their time in the same place. • Harbour seals in the Strait of Georgia showed higher levels of dioxins and furans than those in Puget Sound. PCB levels, however, were more than seven times higher in Puget Sound seals. • The PCB levels found in Puget sound seals are similar to levels that have been found to suppress the immune systems of seals and other marine mammals, leaving them more susceptible to disease. • Although certain chemicals are banned from use in Canada they are still used in other countries. These chemicals can evaporate easily in hot climates and get carried by wind currents (atmospheric transport) to colder regions, such as mountains in British Columbia and the Canadian Arctic, where they condense. For detailed information, including graph data, see In-Depth report [pdf].
