Health of Domestic Mallards (Anas platyrhynchos domestica) Following Exposure to Oil Sands Process-Affected Water Elizabeth M. Beck, † Judit E. G. Smits, ‡ and Colleen Cassady St. Clair* ,† † Department of Biological Sciences, University of Alberta, Z-708, 11455 Saskatchewan Drive, Edmonton, Alberta Canada T6G 2E9 ‡ Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, TRW 2D20, 3280 Hospital Drive NW, Calgary, Alberta Canada T2N 4Z6 * S Supporting Information ABSTRACT: Bitumen extraction from the oil sands of northern Alberta produces large volumes of process-affected water that contains substances toxic to wildlife. Recent monitoring has shown that tens of thousands of birds land on ponds containing this water annually, creating an urgent need to understand its effects on bird health. We emulated the repeated, short-term exposures that migrating water birds are thought to experience by exposing pekin ducks (Anas platyrhynchos domestica) to recycled oil sands process-affected water (OSPW). As indicators of health, we measured a series of physiological (electrolytes, metabolites, enzymes, hormones, and blood cells) and toxicological (metals and minerals) variables. Relative to controls, juvenile birds exposed to OSPW had higher potassium following the final exposure, and males had a higher thyroid hormone ratio (T3/T4). In adults, exposed birds had higher vanadium, and, following the final exposure, higher bicarbonate. Exposed females had higher bile acid, globulin, and molybdenum levels, and males, higher corticosterone. However, with the exception of the metals, none of these measures varied from available reference ranges for ducks, suggesting OSPW is not toxic to juvenile or adult birds after three and six weekly, 1 h exposures, but more studies are needed to know the generality of this result. ■ INTRODUCTION The Alberta oil sands underlie an area of 140 000 km 2 with bitumen deposits that comprise one of the largest crude oil reserves in the world. 1 Bitumen is a mixture of organic compounds and trace metals that can be upgraded into more valuable forms of fuel such as crude oil. 1 Approximately 20% of this resource can be extracted via surface mining; bitumen is recovered from oil-impregnated sand using Clark’s hot water separation process which requires large amounts of water (the typical ratio is 3:1). 2 Some of this water is reused in the mining process, but the remainder has accumulated over the past four decades; 64 of these oil sands process-affected water (OSPW) ponds currently exist, ranging in size from less than 0.01 to over 10 km 2 and with a total surface area of 182 km 2 . 3,4 These ponds may contain residual bitumen, fine clay particulate, and several other mining byproducts including polycyclic aromatic hydro- carbons, naphthenic acids, salts, ammonia, and trace metals. 2 Although the specific constituents of OSPW ponds vary with age and operator-specific mining procedures, many are toxic to wildlife, including invertebrates, 5 amphibians, 6 fish, 7 mammals, 8 and birds. 9 The oil sands industry is therefore obliged by federal and provincial laws to mitigate the risks that process-affected water ponds pose to wildlife, particularly birds. 10,11 In addition to resident birds, over one million migratory water birds pass through the oil sands region each spring and fall traveling to and from the Peace-Athabasca Delta, a globally significant staging area that hosts waterfowl from across North America. 9 OSPW ponds are attractive to waterfowl as they migrate because they afford short-term opportunities to rest and refuel, with a very small proportion using them as long-term opportunities to nest. This issue of bird landings and protection attracted minimal public attention until mass mortalities of migrating flocks occurred in 2008 and 2010, 12 prompting provincial regulators to implement a standardized regional program to monitor bird contacts with OSPW ponds. 3 In 2012, over 20 000 such contacts were reported, highlighting the incomplete solution afforded by the legally imposed bird deterrent systems put in place by industry. 3 This situation creates an urgent need to understand the biological effects of OSPW pond contaminants on waterfowl. That petroleum products are toxic to birds is well documented, but research primarily addresses exposure to compounds associated with conventional oil. 13 Mortality is likely for birds that come into contact with crude oil or residual bitumen (as occurs in the oil sands), because both adhere to Received: March 13, 2014 Revised: July 7, 2014 Accepted: July 8, 2014 Article pubs.acs.org/est © XXXX American Chemical Society A dx.doi.org/10.1021/es501259x | Environ. Sci. Technol. XXXX, XXX, XXX-XXX