When the persistent organochlorine & heavy metal contaminants (CO) accumulate to high enough levels in biological organisms, they cause reproductive failure, congenital abnormalities, & adverse physiological changes. This document reports on the analyzed levels of organochlorines & mercury & eggs & tissues of 24 species of marine birds collected from the Atlantic, Pacific, & Arctic coasts of Canada. Chapters: movements of CO; scientific evidence of health effects caused by CO; measuring contamination; the extent of contamination revealed by monitoring; health of seabirds & status of Canadian seabird pop's.; how organochlorines are measured.