IMPACT OF OIL-SANDS BASED WETLANDS ON THE GROWTH OF MALLARD (ANAS PLATYRHYNCHOS) DUCKLINGS

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1 Environmentl Toxicology nd Chemistry, Vol. 2, No. 2, pp. 7 3, SETAC Printed in the USA /0 $ IMPACT OF OIL-SANDS BASED WETLANDS ON THE GROWTH OF MALLARD (ANAS PLATYRHYNCHOS) DUCKLINGS KIRSTY E. GURNEY, TONY D. WILLIAMS, JUDIT E. SMITS, MARK WAYLAND, SUZANNE TRUDEAU, nd LEAH I. BENDELL-YOUNG* Deprtment of Biologicl Sciences, Simon Frser, University, Burnby, British Columbi VA 1S, Cnd Deprtment of Veterinry Pthology, Western College of Veterinry Medicine, University of Ssktchewn, 2 Cmpus Drive, Ssktoon, Ssktchewn S7N B, Cnd Pririe & Northern Wildlife Reserch Centre, Environment Cnd, 11 Perimeter Rod, Ssktoon, Ssktchewn S7N 0X, Cnd Ntionl Wildlife Reserch Center, Cndin Wildlife Service, 100 Gmelin Boulevrd, Hull, Quebec K1A 0H3, Cnd (Received 22 October 2003; Accepted 9 August 200) Abstrct Identifying the potentil effects of industrilly formed wetlnds on wterfowl popultions is importnt for ssessing the suitbility of such wetlnds in industril reclmtion strtegies. Mllrd ducklings were held in situ on two industrilly formed wetlnds nd one reference wetlnd in northern Albert, Cnd. Duckling mss nd skeletl size were mesured t regulr intervls over 33 d, nd blood ws collected to investigte the nlysis of plsm metbolites (triglyceride nd glycerol) s n indictor of physiologicl condition. In repeted-mesures nlysis of vrince (ANOVA), multivrite ANOVA, nd subsequent multiplecomprisons tests, body mss nd skeletl size were significntly lower in ducklings mintined on the industril wetlnd fter 2,, 9, nd 13 d of exposure. In this sitution, plsm metbolite nlysis did not provide dditionl informtion on mss-independent condition. We conclude tht if the observed differences in growth nd size trnslte into decresed survivl of juvenile wterfowl inhbiting these wetlnds, then popultions of these birds in the re could be negtively ffected. We emphsize the importnce of field-bsed ecologicl reserch in toxicologicl studies of wildlife. Keywords Ans pltyrhynchos Duckling Wetlnds Ecotoxicology INTRODUCTION Oil-snds mining nd extrction is the primry economy in the Fort McMurry re of northestern Albert, Cnd, ccounting for pproximtely 1% of Cnd s totl oil production. The current process for the recovery of oil from the snds involves the Clrk hot-wter extrction method, which simply seprtes the bitumen from the snd through flottion. The recovered bitumen is subsequently upgrded to sweet crude oil. The remining by-products form tilings slurry comprised of fine-prticulte or fine-tiled hydrocrbon solid, snd, wter, nd unrecovered bitumen of no economic vlue. Lrge volumes of this slurry re produced ech yer [1 3], with more expected s the mining industry continues to expnd. Currently, the tilings slurry is stored in retining ponds constructed from mssive dykes mde of leftover snd from the extrction process. This snd hs been ffected by the extrction procedures such tht the interstitil spces re chrged with both wstewter nd industril contminnts. As the dykes compress becuse of their gret mss, dewtering occurs. Consequently, wetlnds form peripherl to the dykes with wter composition of pproximtely 80% of the originl tilings slurry [1]. These wetlnds contin trces of unrecovered bitumen nd other by-products of the oil-snds mining processes (e.g., high sulftes, nphthenic cids, nd slinity) [1 3]. In ddition to wetlnds formed s consequence of the uncontrolled seepge from the erthen dykes, some wetlnds re intentionlly creted by the oil-snds industry s prt of * To whom correspondence my be ddressed (bendell@sfu.c). the mine closeout procedures. These wetlnds re to receive consolidted tilings effluent (CTE), nother by-product of the oil-snds extrction process. In this cse, the tilings slurry receives clcium sulfte to ccelerte floccultion of the fine tils nd other chemicl constituents. As the fine tils consolidte, they dewter, generting CTE tht contins high concentrtions of sulfte nd nphthenic cids. In previous pper [2], we reported on the ecologicl vibility of such wetlnds creted from oil-snds effluent. The conclusion from tht study ws tht the wetlnd ecosystems tht hd developed in response to oil-snds effluent were cpble of supporting low-diversity benthic communities dominted by the Chironomide nd semiqutic plnts, such s cttil. However, fish [2] nd mphibins [3] would be unble to survive. Importntly, the type of wetlnd community tht would become estblished in response to the oil-snds effluent would be hbitt highly suitble to migrtory wterfowl nd insectivorous birds. Hence, n importnt recommendtion generted from the study of Bendell-Young et l. [2], which serves s the objective of the present study, ws to evlute the potentil impcts of such wetlnds on the vin fun tht would use them for breeding. To meet this objective, we rered juvenile ducklings on wetlnds creted from oil-snds effluent, nd we compred their rtes of growth to those of ducklings held on reference wetlnd. Blood smples were tken from the ducklings, nd plsm metbolites (triglyceride nd glycerol) were ssyed to determine if such mesurement would provide useful dditionl informtion regrding mss-independent physiologicl condition [,]. This pper presents the findings regrding the differences in growth nd plsm metbolite profiles be- 7

2 8 Environ. Toxicol. Chem. 2, 200 K.E. Gurney et l. Tble 1. Relevnt wter chemistry for the three wetlnds (AB, Cnd) Prmeter NW HU SI ph Conductivity S/cm Sodium (N) Sulfte (SO ) Ammoni (NH 3 ) Nphthenic cids , /8. 7/7 /3 3/ / /0. For the wetlnd formed from dyke seepge effluent (NW) nd the western hummock zone formed from consolidted tilings effluent (HU), vlues re the men stndrd error of six mesurements during July (n 3) nd August. For the reference wetlnd (SI), vlues re replicte mesures tken once ech in July nd August. tween exposed nd reference birds. Growth ws mesured s the chnge in overll body mss, length nd depth of bill, nd length of trsus nd wing cord. Growth ws chosen s n endpoint for ssessing the suitbility of oil-snds bsed wetlnds s hbitt, both becuse it provides for low mesurement error [] nd becuse strong link hs been demonstrted between body morphology nd survivl nd reproductive success [7 10]. From such comprison, we hope to ssess whether oil-snds bsed wetlnds cn provide suitble hbitt for breeding of vin fun. MATERIALS AND METHODS Study Are The study re ws locted in the Athbscn oil-snds region (the lrgest of four oil-snds res in northestern Albert, Cnd), Suncor Oil-Snds Group, Lese 8. This lese lnd is pproximtely 2 km north of Fort McMurry, on the western bnk of the Athbsc River. The region is prt of Albert s tig forest zone nd is comprised of both undulting plins nd some uplnd res. The undulting plins re chrcterized by muskeg soil nd wetlnds contining blck spruce (Pice mrin), willow (Slix spp.), birch (Betul spp.), nd sphgnum moss (Sphgnum mgellnicum). The higher, welldrined res re primrily vegetted with white spruce (Pice gluc), spen (Populus spp.), nd jck pine (Pinus contort). The tig zone typiclly hs long, severe winters ( to 1 C) nd short summers ( 7 21 C) [11]. Three different experimentl wetlnds were used for the present study, including wetlnd formed from dyke seepge effluent (nturl wetlnd [NW]), the western hummock zone formed from CTE (HU), nd reference wetlnd locted off of the lese nd est of Highwy 3 (SI). Relevnt wter chemistry for the three sites is presented in Tble 1. The dyke seepge wetlnd, or NW, formed in the mid-1980s on the estern side of one of the tilings ponds s result of seepge from lrge dyke tht surrounded the tilings pond. Becuse it ws formed through dyke seepge rther thn constructed, this wetlnd is referred to s being nturl (i.e., NW). Admittedly, this designtion is confusing, in tht nturl would normlly refer to nonimpcted site. However, to mintin consistency mong the vrious studies conducted within this region of the oil snds (see, e.g., [2,3]), we hve retined this terminology to describe this site. In ddition to dyke seepge wter, the wetlnd lso receives surfce runoff wter nd groundwter [12]. In 1998, the surfce re of NW ws pproximtely 1.3 h, of which pproximtely 70% ws open wter. The NW is direct result of industril ctivity in the Athbsc region nd most likely will persist, remining n integrl prt of the finl reclimed lndscpe. Evluting the qulity of this hbitt is criticl in considering reclmtion strtegies. The western hummocks zone study site (i.e., HU), which is locted west of NW, ws creted specificlly by Suncor Oil-Snds Group to study the efficcy of tilings slurry detoxifiction technique. This grssy re hs been intentionlly flooded with CTW periodiclly since 199. After being dischrged, the CTE becme distributed long nturl grdients in the re nd, consequently, mixed with dyke dringe wter, surfce runoff, nd groundwter in the re. This hs led to the formtion of severl shllow pools throughout the grsslnd. Idelly, this lndscpe represents simultion of the finl reclimed ecosystem nd will provide insight regrding the cceptbility of wet-lndscpe reclmtion strtegy. The Highwy 3 reference wetlnd (i.e., SI) is locted pproximtely 2 km south of the ctive oil-snds Lese 8. In 193, the excvtion of grvel left n empty borrow pit t this site. The re slowly becme vegetted, nd shore mrsh type wetlnd formed t the edge of the lke tht filled in the pit. The lke is similr to NW in tht it is primrily open wter nd is surrounded by qutic vegettion nd shrubs. However, the wter in SI is deeper thn tht in NW. The SI wetlnd, s indicted by its wter chemistry (Tble 1), represents reltively undisturbed ecosystem tht is remote from industril ctivity. Growth One-dy-old mllrd ducklings (mixed gender) from Whistling Wings (Hnover, IL, USA) rrived in Fort McMurry on My 19, After 8 h of cclimtion, ech bird ws fitted with metl-web identifiction tg nd mesured (t 0d; My 21). Body mesurements obtined for ech bird included body mss ( SE throughout) (pesol 0.3%), length of the left wing cord ( 0. mm), length of the right trsus ( 0.02 mm), length of the bill ( 0.02 mm), nd depth of the bill (t thickest point, 0.02 mm). Subsequent mesures of growth were tken on My 23 (t 2 d), My 2 (t d), My 30 (t 9 d), June 3 (t 13 d), June 9 (t 19 d), June 1 (t 2 d), nd June 23 (t 33 d). Birds were held in situ on NW, HU, nd SI. Fifteen 3-d-old ducklings were plced into one of three stble, stinless-steel pens ( cm) on ech experimentl site. Pens were plced such tht t lest one-third of the enclosed re included shoreline nd open wter of the wetlnd. Pens were open t the bottom, llowing ducklings free ccess to nturl forge mteril (qutic plnts nd invertebrtes). Pens were modified such tht elevted pltforms (30 cm) nd shelter boxes lined with strw were vilble inside ech pen. For the first week of exposure, ll ducklings were confined to their shelter boxes t night. Por-

3 Duckling growth on industril wetlnds Environ. Toxicol. Chem. 2, tions of ech pen lso were provided with roof so tht ducklings hd ccess to cover. An importnt experimentl spect of the present study ws tht ducklings were provided Msterfeeds (London, ON, Cnd) duck nd goose strter (20% protein) d libitum. This ws to ensure tht ny detected differences in bird growth could be ttributed to overll hbitt effects rther thn simply to differences in food ccessibility (e.g., mong-pen vrition in invertebrte density) within the experimentl cges. A hnging feeder ws suspended from the roof of ech pen so tht the food ws protected from wter spoilge nd ws ccessible to ll ducklings. Additionlly, the pens were moved every d (within the experimentl sites). This limited the environmentl dmge tht could be done within one re, nd it lso llowed the ducklings to hve continully renewed ccess to nturl forge mteril. Plsm metbolite mesurements Blood smples (1 3 ml) were tken from ll ducklings t 13 nd 33 d of ge vi the jugulr vein using heprinized syringe nd 2-guge, 0.-in. needle. All blood ws collected between 000 nd 1100 h, nd hndling times were 1 to min. Whole blood ws centrifuged nd the plsm stored t 20 C until ssyed. Plsm smples were ssyed in duplicte for triglyceride nd glycerol using stndrd dignostic ssy (Kit 337-B; Sigm-Aldrich, Okville, ON, Cnd) following the mnufcturer s protocol, except tht ssys were modified for use with smll plsm volumes ( l). The interssy coefficient of vrition ws 11.% (n 7) nd 18.1% (n 7) for plsm triglyceride nd plsm glycerol, respectively. Assessment of toxicnt exposure At the termintion of the study (t 33 d), the ducklings were killed nd necropsied. A subsmple of 10 birds (n ech from NW nd SI) were rndomly selected for immedite necropsy (i.e., within 2 min of deth). Smples of bile were removed from the gllbldders of these birds using 1-ml tuberculin syringe (27-guge, 0.-in. needle). Smll (1- to 2- g) cross-sections of the left lobe of the livers of these birds lso were removed nd plced in Cryovc tubes (Est Sddle Brook, NJ, USA). These smples were immeditely frozen in liquid nitrogen ( 173 C). Both bile nd liver smples were sent to the Ntionl Wildlife Reserch Lbortory, Cndin Wildlife Service, in Hull, Quebec, for further nlyses. The bile smples were nlyzed for polyromtic hydrocrbon (PAH) metbolites ccording to the methods described by Krhn et l. [13]. Metbolites of interest included pyrene, benzo[]pyrene, nphthlene, nd phennthrene. Liver smples were nlyzed for ethoxyresorufin O-deethylse (EROD) ctivity ccording to the techniques described in the Cndin Wildlife Service Lbortory Services Section Report [1]: BMK-EROD Here, we use levels of EROD s mesure of induced cytochrome P0. The use nd cre of project nimls conformed to guidelines specified by the Nturl Sciences nd Engineering Reserch Council of Cnd nd the Cndin Council on Animl Cre. Dt nlyses All sttisticl nlyses were performed using SAS softwre (SAS Institute, Cry, NC, USA) [1]. All grphs were produced in SigmPlot (SPSS, Chicgo, IL, USA) [1]. In ll nlyses, only dt from birds tht survived the durtion of Tble 2. Totl number of mle nd femle ducklings tht survived the 33-d exposure Site (AB, Cnd) Highwy 3 b Pen 1 Pen 2 Pen 3 Hummocks Pen 1 Pen 2 Pen 3 Nturl wetlnd Pen 1 Pen 2 Pen 3 Surviving birds (n) Femles Mles Totl birds Ducklings re seprted by pen nd by gender. b Reference wetlnd the experiment were used (Tble 2). Exct cuses of duckling mortlity re unknown, but these deths most likely resulted from ggression by other ducklings within the enclosures. Growth. Dt were checked for normlity nd heteroscedsticity (procedure UNIVARIATE), nd multivrite nlysis of vrince (ANOVA) using the generl liner model (GLM) ws used to exmine the effect of gender on duckling size. The model found tht the effect ws significnt (F.98, p ) nd tht this difference becme more pronounced s the ducklings ged. Hence, dt for mle nd femle ducklings were nlyzed seprtely. The GLM procedure ws used on ech dtset to exmine intrsite vribility. In generl, pens within the sites were not found to hve significntly different mesurements for ny of the growth prmeters (p 0.0); therefore, ll pens within site were pooled for both the femle nd the mle ducklings. Smple sizes for the nlysis re presented in Tble 2. The mss of the birds ws compred by repeted-mesures nlysis (mixed), nd Ryn-Einot-Gbriel-Welsch multiplecomprisons procedure (corrected for the number of comprisons) ws used to group the dt by site. Wing cord, trsus, bill length, nd bill depth mesurements were nlyzed s indictors of generl body size. A multivrite ANOVA (GLM) ws used to exmine between-site differences of these dependent vribles t ech smpling time, nd Ryn-Einot- Gbriel-Welsch multiple-comprisons procedure (corrected for the number of comprisons) ws used to group the dt by site. Plsm metbolites. As with growth, ll plsm smples within site were pooled for nlysis. Glycerol ws normlly distributed (Shpiro-Wilks test, p 0.0); however, triglyceride levels were nonnorml (p 0.001) nd were log 10 trnsformed for nlysis. A multivrite ANOVA (GLM) ws used to determine if differences in plsm triglyceride nd glycerol levels were dependent on body mss t 13 nd 33 d of ge or on gender. We observed no effect of duckling mss (p 0.0) or sex on plsm triglyceride or glycerol levels t either ge (p 0.1 in ll cses). Plsm metbolite levels lso were independent of sex; hence, sexes were pooled for subsequent nlysis. A multivrite ANOVA (GLM) on pooled dt ws pplied to determine differences in plsm triglyceride levels between sites in ducklings t 13 or 33 d of ge.

4 0 Environ. Toxicol. Chem. 2, 200 K.E. Gurney et l. Fig. 1. Body mss s function of time in femle juvenile mllrds. A repeted-mesures nlysis found tht chnge in body mss ws dependent on site (F , p 0.0) nd time (F , p ). Vlues re presented s the men stndrd error. Significnt differences re denoted with n sterisk (*). Wetlnd sites re in Albert, Cnd. Assessment of toxicnt exposure. Both EROD nd PAH metbolite dt were exmined for gender differences using GLM procedure. The GLM lso ws used to determine site differences in ctivity of EROD in the liver nd in concentrtions of PAH metbolites in the bile. The PAH metbolites were nlyzed s both independent (ANOVA) nd dependent (multivrite ANOVA) vribles. RESULTS Growth We obtined dt regrding totl body morphology for 3 femle nd 3 mle ducklings. The mss of femle ducklings chnged significntly over time (F , p ) (Fig. 1). Site ws significnt in the model (F , p 0.0,), with no significnt interction between site nd time (F , p 0.0). The site effect ws driven by the significntly higher msses of the SI femles ( 0.0) between dys 2 nd 13. After 13 d, the msses of HU nd NW birds were no longer significntly lower thn the mss of SI birds. However, the generl trend of bird mss for wetlnd SI bird mss for wetlnd HU bird mss for NW ws observed until the termintion of the present study. Body size of the femles (wing cord length, trsus length, bill depth, nd bill length) lso showed significnt site effect t t 2d(F 8 3., p 0.002), t d(f 8 2., p 0.02), t 9d(F 8 3.7, p 0.001), nd t 13d(F 8 2.9, p 0.01) (Fig. 2). Single-vrible ANOVA vlues nd Ryn-Einot-Gbriel-Welsch results show tht this effect resulted primrily from differences in the trsus nd the bill length, with the wing cord nd bill depth mesurements being less sensitive (Fig. 2). The mle ducklings show the sme generl trend s the femles (Figs. 3 nd ). Site nd time were both significnt fctors in the repeted-mesures model (site: F 2 7., p 0.000; time: F 7 3.9, p ), wheres the interction of site nd time were not (F 1 0.9, p 0.0). Fig. 2. Dt regrding femle trsus (), length of bill (b), wing chord (c), nd depth of bill (d) re shown. Multivrite nlysis showed site effect for body size (s mesured by wing chord, trsus, bill length, nd bill depth) t t 2,, 9, nd 13 d. Significnt differences re denoted with n sterisk (*). See text for full detils. Wetlnd sites re in Albert, Cnd.

5 Duckling growth on industril wetlnds Environ. Toxicol. Chem. 2, , p 0.0). At 13 d of ge, plsm glycerol levels were significntly higher t NW compred with both HU (p 0.01) nd SI (p 0.0) (Tble ). Evidence for toxicnt exposure Ducklings on NW did not pper to be exposed to significnt levels of hlogented romtic hydrocrbons (HAHs), s indicted by EROD ctivity (Tble ). However, ducklings were exposed to higher levels of PAHs, s indicted by metbolites of these compounds in their bile (Tble ). Fig. 3. Body mss s function of time in mle juvenile mllrds. A repeted-mesures nlysis found tht chnge in body mss is both site nd time dependent (site: F 2 7., p 0.000; time: F 7 3.9, p ). Vlues nd sterisks (*) s described in Figure 2. Wetlnd sites re in Albert, Cnd. Plsm metbolites We found no difference in plsm triglyceride levels between sites in ducklings t 13 d (F , p 0.0) or 33 d(f , p 0.0) of ge (Tble 3). Plsm glycerol levels did differ significntly mong sites in ducklings t 13 dofge(f 2.7, p 0.02) but not t 33 d of ge (F 2 DISCUSSION Growth Mllrd ducklings held in situ on NW nd HU weighed less thn mllrd ducklings tht were held in situ on SI. Furthermore, length of trsus, bill length, nd bill depth were ll smller in ducklings held on NW nd HU compred to those held on SI. This effect (SI HU NW) occurred for both femles nd mles, lthough it ws most obvious in the femle ducklings. The vlues for body mss nd size t ll sites fll within the nturl rnge of vribility for gme-frm mllrds [17,18] but re slightly greter thn those vlues reported for wild mllrds [19]. Plsm metbolite nlysis Plsm triglycerides hve been used successfully to estimte fttening rtes in nimls undergoing extreme lipogen- Fig.. Dt regrding mle trsus (), length of bill (b), wing chord (c), nd depth of bill (d) re shown. Multivrite nlysis showed site effect for body size (s indexed by wing chord, trsus, bill length, nd bill depth) t t 2,, 9, 13, nd 19 d. Significnt differences re denoted with n sterisk (*). See text for full detils. Wetlnd sites re in Albert, Cnd.

6 2 Environ. Toxicol. Chem. 2, 200 K.E. Gurney et l. Tble 3. Vrition in plsm triglyceride nd glycerol levels in 13- nd 33-d-old ducklings (where ge is equivlent to dys of exposure) rered t different sites Site Metbolite Duckling ge (d) HU NW SI Triglyceride Glycerol See text for detils regrding sites. Vlues re the mens stndrd error (n 17 19). HU hummocks; NW dyke seepge wetlnd; SI Highwy 3 or the reference wetlnd (ll sites in AB, Cnd). esis, such s during migrtory fttening []. Here, we used plsm triglycerides s n indictor of mss-independent physiologicl condition. However, in contrst to duckling growth, plsm metbolite (triglyceride nd glycerol) nlysis either reveled no site differences (s in the cse of triglycerides compred to growth mesurements) or suggested site differences tht were inconsistent with the growth dt. Hence, differences in plsm triglyceride levels indictive of differences in rtes of lipogenesis (fttening) or low plsm glycerol levels indictive of fsting or strvtion were not detected. This suggests tht metbolite nlysis my be poor indictor of condition or nutritionl sttus in generl mong free-rnging nimls, most of which will be in neutrl or positive energy blnce (see, e.g., []). Extrinsic nturl fctors tht influence the body morphology of wterfowl include density of food nd dietry nutritionl content [20 22]. However, ll ducklings received supplementl feed d libitum in ddition to forge tht they cquired from the wetlnds, so ny potentil intersite differences in nturl food vilbility could be ccounted for in the present study. Alterntively, exposure to toxic substnces, such s crude oil, substnce present within oil-snds wetlnds, cn ffect morphologicl prmeters [23] nd could hve been responsible, in prt, for effects observed in the present study s discussed below. Evidence for toxicnt exposure King nd Bendell-Young [2] recently demonstrted tht grit ingestion by juvenile mllrds could be significnt route of contminnt exposure, specificlly for oil-snd relted compounds such s oil nd grese. Bsed on known concentrtions of oil nd grese contined in oil-snds wetlnds [12], King nd Bendell-Young [2] determined tht for 21-d, 1-h forging period, ducklings ingesting sediments from oil-snds bsed wetlnds consume pproximtely.1 mg of oil nd grese. To determine if ingestion of sediment by ducklings could result in exposure to oil-snds derived contminnts, we determined levels of EROD nd of PAH metbolites. A detoxifiction enzyme, EROD commonly is used in toxicity studies s biologicl mrker of exposure to HAHs, such s dioxins nd polychlorinted biphenyls [2,2,]. In the present study, the ctivity of EROD in livers of NW birds ws pproximtely equl to tht in reference birds. Furthermore, the rnge of EROD vlues for ll ducklings in the present study ws extremely low ( pmol/min/mg protein) reltive to those in other studies of mllrds [27,28,], which report EROD vlues rnging from 93. to 71.2 nd from 70 to 130 pmol/ min/mg protein, respectively. Hence, given the low vlues of EROD in the present study, HAH exposure on the study sites likely ws miniml. Exposure to PAHs, however, did occur. Two PAH metbolites, pyrene nd nphthlene, were found t significntly incresed concentrtions in the bile of NW ducklings reltive to tht in SI ducklings. This suggests tht these birds were exposed to higher levels of the prent PAHs, possibly through ingesting wetlnd sediment s grit, consequence of these wetlnds being bsed on oil-snds effluent contining high concentrtions of bitumen, oil, nd grese compounds tht contin PAHs. Hence, differences in growth observed between ducklings rered on oil-snds wetlnds versus reference wetlnds could be ttributed, in prt, to the differentil exposure to oil-snds bsed contminnts. Moreover, the most obvious nturl fctors tht could led to differences in growth rtes (e.g., climte, temperture, nd moisture) nd food vilbility were controlled for by conducting the experiment in situ nd by providing food d libitum. This further supports the conclusion tht the reduced growth in ducklings rered on oilsnds bsed wetlnds results, in prt, from incresed exposure to oil-snds derived contminnts. Implictions Rhymer [29] hs noted tht smller ducklings hve incresed thermoregultory chllenges nd tht hevy mllrd ducklings hve to expend less energy per grm of body weight to mintin homeothermy. Cox et l. [10] showed conclusive evidence tht survivl of mllrd ducklings is positively re- Tble. Summry of heptic ethoxyresorufin O-deethylse (EROD) ctivity nd polyromtic hydrocrbon (PAH) metbolite levels in the bile of juvenile mllrds held on the nturl wetlnd (NW) nd reference wetlnd (SI) PAH metbolites EROD Pyrene* BP Nphthlene* Phennthrene NW WI The EROD ctivity is mesured in nmol/min/mg protein nd metbolites re mesured s PAH equivlents (see Krhn et l. [13]). For ll mesurements, vlues re the men stndrd error. Vlues tht re significntly different by site (p 0.0) re mrked with n sterisk. BP benzo[]pyrene.

7 Duckling growth on industril wetlnds Environ. Toxicol. Chem. 2, lted to growth. Therefore, prefledging ducklings rered on oil-snds bsed wetlnds, given their smller size, my be less likely to survive compred to ducklings rered on wetlnds not receiving oil-snds effluent. Currently, prt of the mine closeout procedure incorportes the use of wetlnds bsed on CTE. Furthermore, becuse current mine closeout plns do not include removl of the huge snd dykes used to enclose the fine-tils slurry, dyke seepge will continue for mny yers (estimted s 100 yers or longer pst mine closeout) [1 3]. The findings of the present study suggest tht these oil-snds bsed wetlnds re poor-qulity hbitts, s indicted by the reduced growth in ducklings inhbiting the wetlnd. Reduced duckling growth hs been linked to poorer survivl nd, thereby, to reduced recruitment into the popultion s whole [7 10]. Hence, lrger-scle studies t the popultion level re needed to determine wht impct current mining ctivities could hve on bird popultions within the region. Once the impct is ssessed, pproprite reclmtion strtegies cn be put in plce to prevent further dverse effects on the vin communities within this region of northern Albert, Cnd. Acknowledgement Funding for the present study ws provided by the Environmentl Science nd Technology Allince of Cnd, with mtching funds from Ntionl Science of Engineering Reserch Council of Cnd in the form of n Industril Orientted Reserch Grnt to L. Bendell-Young. We thnk Kim St. Onge nd P. Sing for help with running the metbolite ssys. The support nd dvise of Don Sheern lso is grtefully cknowledged. REFERENCES 1. Bishy FS, Nix PG Constructed wetlnds for tretment of oil-snds wstewter. Technicl Report. Prepred for Suncor Oil-Snds Group. EVS Environmentl Consultnts, North Vncouver, BC, Cnd. 2. 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