Semipermeable Membrane Devices (SPMDs) were deployed for 2 weeks in waters ofthe Athabasca and Lesser Slave Rivers and in four pulp mill effluents and wastewater from one oil sands mining and upgrading facility. Success of recovery of the SPMDs was 66 %, with loss caused by high water velocity and shifting channels and sediments. SPMD extracts accumulated chemicals that induced mixed function oxygenase (MFO) in a fish cell line. For expressing the potency of SPMD extracts as inducers in fish cells, MFO induction in cells exposed to SPMD extracts was compared to MFO induction in cells exposed to 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD). This does not imply that the SPMD extracts contained TCDD or any other dioxin or furan, only that the extracts contained chemicals that were equivalent in MFO-inducing potency to a certain amount of TCDD. MFO induction was expressed as "EROD potency equivalents in pg/g".
Extracts of SPMDs from pulp mills were two to five times as potent as extracts of SPMDs exposed to background river water. SPMD extracts from three of the four pulp mill effluents tested (Weldwood, Alberta Newsprint and Slave Lake Pulp) had 62.0, 53.5, and 29.7 pg EROD potency-EQ/g, respectively, significantly more than in Athabasca River water (12.6 pg EROD potency-EQ/g = "background"). SPMDs exposed to effluent from Millar Western (23.0 pg EROD potency-EQ/g) had potencies within the 95 % confidence interval o f background. The levels of MFO induction in SPMDs exposed to river water increased downstream of Fort McMurray. In this area, SPMDs accumulated inducers from the river at levels ranging from 58.5 to 728 pg EROD potency-EQ/g. SPMD accumulation was highly variable, which indicated an unknown source of inducers, possibly an effluent from the town or input from natural erosion of the oil sands.
SPMDs deployed in effluent from Suncor accumulated the most MFO-inducing chemicals (16,800 pg EROD potency-EQ/g), with induction potency over 20 x that of SPMDs from river water upstream of Suncor. Although this study was preliminary, the results indicated that SPMDs from the four pulp mill effluents contained small quantities of MFO inducers. Compared to MFO induction by extracts of SPMDs deployed in two Ontario bleached kraft mill effluents, the pulp mill effluents from the Athabasca River were one third to one twentieth as potent. By contrast, very high quantities of MFO inducers were accumulated from Suncor effluents. SPMDs deployed in Athabasca River waters downstream of Fort McMurray also contained inducers, indicating some unknown anthropogenic or natural source in this area.