Effect of diluted bitumen on the survival, physiology, and behaviour of the zebra finch (Taeniopygia guttata)

Given ongoing and potential increases in shipment of diluted bitumen (dilbit) out of the port of Vancouver, there is a need for toxicity data to assess the impact of catastrophic dilbit spillage on wildlife. Peer reviewed literature on dilbit toxicity is limited to teleost fish, despite the importance of coastal waters as habitat for diverse bird fauna. We used the zebra finch (Taeniopygia guttata) as a tractable, avian model system for preliminary studies on Cold Lake blend dilbit. Objectives were to establish methodology appropriate for determining dilbit toxicity to birds, determine a range of lethal and sublethal doses, and obtain physiological and behavioural endpoints. We conducted three 14-day exposure trials with dosages from 0-12 ml dilbit/kg bw day. Mortality was associated with mass loss, external oiling, elevated OXY, and decreased pectoral muscle mass. In addition, evidence for sub-lethal effects included elevated EROD, increased wet gizzard mass, and behavioural changes.