Using wood frog (Lithobates sylvaticus) tadpoles and semipermeable membrane devices to monitor polycyclic aromatic compounds in boreal wetlands in the oil sands region of northern Alberta, Canada

Abstract

Several recent studies have reported evidence that surface mining operations of bitumen in northern Alberta's oil sands (OS) region contribute significantly to the atmospheric deposition of metals and polycyclic aromatic compounds (PACs) within the vicinity of OS development. The present study examines the accumulation of PACs in boreal wetlands at varying distance from OS industrial activities with the use of semipermeable membrane devices (SPMDs) and wood frog (Lithobates sylvaticus) tadpoles. SPMDs were deployed in shallow lentic waterbodies adjacent to wood frog egg masses and were retrieved, along with tadpoles, approximately 35-45 days later. The highest concentrations of PACs were detected in SPMDs deployed within a 25 km radius of surface mining activity, consistent with snow deposition studies of PACs in the region. In wetlands located within the vicinity of surface mining activity, PAC profiles of SPMDs and wood frog tadpoles were dominated by C1-C4 alkylated PACs, including alkylated dibenzothiophenes, which are strongly indicative of petrogenic sources. Contrary to differences seen in the SPMD PAC concentrations, there were no obvious differences in the ∑PACs in wood frog tissue between wetland study sites, although alkylated fluorenes were found to be higher in tadpoles collected from a wetland located within 10 km of two bitumen upgrading facilities. The use of SPMDs in tandem with wood frog tadpoles can help assess the potential exposure of aquatic organisms to PACs in boreal wetlands.

Tree Swallow (Tachycineta bicolor) nest success and nestling growth near oil sands mining operations in northeastern Alberta, Canada

“…Each of the eight sites supported 15 to 30 nest boxes and was near a wetland or pond. Four sites (sites 1, 2, 3, and 4) were within 5 km of active mine operations and mine upgraders and were exposed to deposition from aerial emissions (Bari et al 2014;Mundy et al 2019), as well as potentially to contaminants in water originating from bitumen processing. Tree Swallow populations had been established at some of these sites prior to this study (Smits et al 2000;Gentes et al 2006Gentes et al , 2007aGentes et al , 2007bHarms et al 2010).…”

“…This site was an overburden dump from mine development and now supports an upland forest and wetland habitat. Amphibian tadpoles from the wetland at this site had high levels of polycyclic aromatic compounds in tissues (Mundy et al 2019). Site 4 was adjacent to a reservoir used to store water for mine operations.…”

“…Waste materials are released in tailings process water and in air emissions from the mine upgraders, potentially contaminating surface waters and the surrounding environment (Barton and Wallace 1979;Kelly et al 2010;Puttaswamy and Liber 2012). Passive air monitoring sampling devices placed at wetlands near surface mining activity accumulated greater amounts of polycyclic aromatic compounds compared with wetlands located south of Fort McMurray (Cruz-Martinez et al 2015;Mundy et al 2019). Organic and inorganic compounds measured in snow were attributed to oil sands emissions (Kelly et al 2009(Kelly et al , 2010.…”

Advances in science and applications of air pollution monitoring: A case study on oil sands monitoring targeting ecosystem protection

“…As the spring melt coincides with the wood frog breeding season, wood frog early life stages may be exposed to potentially high COC levels during early stages of development. In particular, amphibians may be exposed to detrimentally high levels of PACs during embryo development, which is a particularly sensitive point in their life cycle (Mundy et al 2018). Amphibians have shown to be sensitive indicators of wetland quality during previous studies on wetlands containing OS processed water (Hersikorn, Ciborowski, and Smits 2010;Pollet and Bendell-Young 2000).…”

“…(C) ∑PACs accumulated in SPMDs represented as C free (pg L −1 ) deployed in 2013 and 2014 as a negative exponential relationship with distance to upgraders (r 2 = 0.66). As noted above, Gateway wetland is not included in this analysis (Mundy et al 2018).…”