ORGANIC CONTAMINANTS IN THE NORTHWEST ATLANTIC ATMOSPHERE AT SABLE ISLAND, NOVA-SCOTIA, 1988-89

Air samples were collected at Sable Island in January 1988 and 1989 for organochlorine (OC) compounds, and July-August 1989 for OCs and polycyclic aromatic hydrocarbons (PAHs). Mean concentrations of OCs (pg/m3) were: hexachlorocyclohexanes (alpha-HCH + gamma-HCH) = 250, polychlorinated biphenyls (PCBs, sum of 38 congeners) = 52, polychlorocamphenes (PCCs) = 35, , chlordanes + nonachlors = 15, heptachlor epoxide = 5.2, p,p'-DDT + p,p'-DDE = 4.5. Endosulfan (sum of two isomers) and dieldrin concentrations were 24-159 and 9-12 pg/m3 in summer samples. The sum of 3-5 ring PAHs ranged from 553 - 842 pg/m3, and was dominated by 3-ring (92%) followed by 4-ring (6%) and 5-ring (2%) compounds. HCHs in rain (3.6-7.3 ng/L) and seawater (1.2-2.1 ng/L) were similar to other values reported for the North Atlantic and eastern Canada. Results show the importance of atmospheric transport in delivering contaminants to the Scotian Shelf and the advantages of Sable Island as a monitoring site.