Upload
buicong
View
215
Download
2
Embed Size (px)
Citation preview
1
The Slave River is a culturally important waterway for Northerners with development activity upstream. This report summarizes 35 years of water quality data from the Slave River. The assessment revealed some long term trends in water quality parameters such as phosphorus and sulphate, as well as some long term trends in flow. The ecological significance of these trends needs to be better understood. This assessment also highlighted the need for site-specific water quality objectives to be able to better assess future water quality conditions of the river. Overall, fewer organic compounds, and at lower levels, were found in the water and suspended sediment samples taken during the Follow-Up Study (2000-2010) than in the earlier Slave River Environmental Quality Monitoring Program (1990-1995).
To ensure the health of the river, monitoring will continue. All partners should work closely together to expand the knowledge and understanding of the Slave River aquatic ecosystem.
The Slave River at Fort Smith
Slave RiverWater and Suspended Sediment Quality in the Transboundary Reach of the Slave River, Northwest Territories
Report Summary:
2
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
Information contained in this publication or product may be reproduced, in part or in whole, and by any means, for personal or public non-commercial purposes, without charge or further permission, unless otherwise specified.
You are asked to:
Exercise due diligence in ensuring the accuracy of the materials reproduced;
Indicate both the complete title of the materials reproduced, as well as the author organization; and
Indicate that the reproduction is a copy of an official work that is published by the Government of Canada and that the reproduction has not been produced in affiliation with, or with the endorsement of the Government of Canada.
Commercial reproduction and distribution is prohibited except with written permission from the Government of Canada’s copyright administrator, Public Works and Government Services of Canada (PWGSC). For more information, please contact PWGSC at: 613-996-6886 or at: [email protected].
www.aandc-aadnc.gc.ca 1-800-567-9604 TTY only 1-866-553-0554
QS-Y376-000-EE-A1 Catalogue: R3-174/2012E ISBN: 978-1-100-21539-6
© Minister of Aboriginal Affairs and Northern Development, 2012
Cette publication est aussi disponible en français sous le titre : Qualité de l’eau et des sédiments en suspension dans le tronçon transfrontalier de la rivière des Esclaves, dans les Territoires du Nord Ouest
3
The Slave River…• isthelargesttransboundaryriverinthe
NorthwestTerritories;
• hasahugewatershedthatincludesthePeaceRiver,AthabascaRiver,LakeAthabascaandtheLowerSlaveRiversub-basins,whicharelocatedintheNorthwestTerritoriesandprovincesofAlberta,BritishColumbiaandSaskatchewan;
• isanimportantcomponentoftheMackenzieRiverBasin,contributingapproximately75%oftheinflowtoGreatSlaveLake;
• hasameanannualflowof3400m3/s,whichmeansthatonaverage3.4millionlitresofwaterpassbythecommunityofFortSmitheachsecond(asacomparison,theHayRiverhasameanannualflowof115m3/s);
• carriesanaverageof30milliontonnesofsuspendedsedimenttoGreatSlaveLakeeachyear,almostallofwhichisdepositedbetweenMayandOctober.Duringthesemonths,thisisequaltoabout4000largedumptruckloadseachday;and,
• supportsawidevarietyoffurbearers,fishandthemostnortherlycolonyofwhitepelicans.
The Slave River at Fort Smith
4
Overthelastseveraldecades,resourcedevelopmentintheupstreamportionoftheSlaveRiverwatershedhasincreased.Theseactivitiesmainlyincludeoilandgasdevelopments;oilsandsoperations;pulpandpapermills;coalanduraniummining;agriculture;andforestry(Figure1).Further,theW.A.CBennettDam,ahydroelectricdevelopmentonthePeaceRiverinnorthernBritishColumbia,existsupstreamintheSlaveRiverwatershed.NorthernershaveraisedconcernsthattheseupstreamdevelopmentshaveimpactedthewaterresourcesintheNWT.TheseconcernsareespeciallyrelevantintheNorth,asmanyresidentsmaintainatraditionallifestyleandhaveacloseconnectiontotheland.Inaddition,climatechangehasthepotentialtoinfluencetheSlaveRiver.
Figure 1: Current activities in the Slave River watershed (not including specific oil and gas and oil sands operations)
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
5
Purpose of the ReportAboriginalAffairsandNorthernDevelopmentCanada’s(AANDC)SlaveRiverreportdescribesthewaterandsuspendedsedimentconditionsintheriver.
UsinginformationfromAANDCandEnvironmentCanada,thereportaimsto:
• provideageneraloverviewofthecurrentstateofwaterquality,suspendedsedimentqualityandflowsinthetransboundaryreachoftheSlaveRiver;
• determineifwaterqualityandflowshavechangedovertime;
• helptoaddresscommunityconcernsaboutmetalsandorganiccompoundsintheriver;
• supportthedevelopmentofwaterqualityobjectivesforthetransboundarybilateralagreement;and,
• outlinepotentialareaswheretheexistingAANDCSlaveRivermonitoringprogramcanbeimproved.
Thereportisjustonepieceofthepuzzle.CombiningtheresultsfromthisstudywithinformationgeneratedfromotherSlaveRiverandSlaveRiverDeltamonitoringprogramsandresearchwillhelpnorthernersgainabetterunderstandingofthehealthoftheSlaveRiversystem.
The Slave River, near the Rapids of the Drowned
6
Understanding Water QualityWaterqualitynaturallyvariesfromplacetoplace,withchangingseasons,climatevariationsandthetypesofsoilandrockthroughwhichthewatermoves.Watercancarryplantdebris,sand,siltandclay,makingthewatermuddyorcloudy(i.e.,measuredassuspendedsediments).Wateralsocarriesdissolvedmineralsandmetalsfromrocks,anddissolvedsaltssuchascalciumandmagnesium.Nutrientsinwatersuchasphosphorousandnitrogenareimportantforaquaticplants.Ingeneral,thesesubstancesarenotconsideredharmfultohumanoraquaticlife.
Waterqualitydescribesthechemical(e.g.,metalconcentrations),physical(e.g.,temperature)andbiologicalcharacteristics(e.g.,bacterialevels)ofwaterusuallywithrespecttoitssuitabilityforaparticularpurpose.Althoughscientificmeasurementsareusedtodescribethequalityofwater,itisnotasimplethingtosaythat“thiswaterisgood,”or“thiswaterisbad.”Forexample,waterthatisperfectlygoodtodrinkmightnotbegoodenoughforaverysensitivespeciesoffish.Whenapersonasksaboutwaterquality,theylikelywanttoknowifthewaterisgoodenoughtodrinkandswimin,orifthequalityofthewaterissuitableforaquaticplantsandanimals.
Guidelinesareestablishedtoprotectwaterforaquaticlifeordesignatedusessuchasdrinkingandrecreation.ComparingsubstancesfoundinwatertoguidelinesisonewaytodetermineiftheSlaveRiverwaterqualityis“good”.Goodwaterqualitygenerallymeansthatthelevelsofsubstancesarebelowtheguidelinevalues.ThedatafromthisstudywerecomparedtotheHealthCanada’sHealth-BasedGuidelinesforCanadianDrinkingWaterQualityandRecreationalWaterQuality,aswellastotheCanadianCouncilofMinistersoftheEnvironmentGuidelinesfortheprotectionoffreshwateraquaticlife.
Anotherwaytounderstandwaterqualityistocheckwhetherwaterqualityconditionshavechangedovertime.Changescouldbeduetohumanactivitiesand/ornaturaloccurrences.Thisstudylookedatwhetherwaterqualityhaschangedsince1972,whenregularsamplingbeganontheSlaveRiver.
Juanetta Sanderson, Erv Allen and Wayne Starling sampling the Slave River, September 2010.
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
7
What were the Samples Tested for?Over200watersamplesand27suspendedsedimentsampleshavebeencollectedfromtheSlaveRiverandanalyzedforover500differentsubstances.
TounderstandthebasicchemistryofthewaterandsuspendedsedimentqualityoftheSlaveRiver,sampleswereregularlyanalyzedforroutineparameters(i.e.,pH,totaldissolvedsolids,totalsuspendedsolids,alkalinityandorganiccarbon),nutrients(i.e.,phosphorus)andmajorions(i.e.,calciumandmagnesium).
Tohelpaddressconcernsregardingupstreamactivities,waterandsuspendedsedimentsampleswerealsotestedformetalssuchasaluminum,arsenic,copper,lead,vanadiumandzinc,aswellascompoundssuchaschlorophenols,organochlorinepesticides,PCBs,dioxins,furansandhydrocarbons.Someofthesesubstancescanbenatural,butsomeareknowntobeassociatedwithupstreamdevelopment.
Why sample suspended sediments?
Due to the size and organic content of the suspended sediment in the Slave River, metals and organic compounds tend to attach to these particles and can be carried long distances from their source.
What are metals?
Metals, such as copper and lead, occur naturally, and most can be found in the rocks and soil in the NWT. Weathering of the rocks can release metals into rivers and lakes, therefore it is relatively common to find naturally occurring metals in surface waters. Some metals are required for all living things. However, some activities such as mining and other industrial developments, the burning of fossil fuels, land clearing and even forest fires can release higher than natural levels. These can be harmful to aquatic life.
What are chlorinated compounds?
Chlorinated compounds, more commonly known as persistent organic pollutants (POPs), are made by humans. Some are pesticides for killing insects or diseases that attack crops. Certain chlorinated compounds, such as chlorophenols, can be released from pulp and paper mills and municipal facilities. In the past, polychlorinated biphenyls or PCBs were used in electrical equipment. Dioxin and furans, another group of compounds, are released into the environment through combustion and wood pulp that is bleached with chlorine to produce paper products. POPs can cause harm to living things and last a long time in nature. Most POPs in the North arrive through air or water currents from other parts of Canada and the world.
What are hydrocarbons?
Hydrocarbons also referred to as polycyclic aromatic hydrocarbons (PAHs), are chemical compounds that are present in air, water and soil in small amounts virtually everywhere. Natural sources include forest fires, volcanic eruptions and natural petroleum and natural gas deposits. PAHs are also associated with industrial oil sands projects, other industries and urban runoff. These compounds can enter the river through effluent discharge, by air or runoff from the land. Hydrocarbons can cause harm to living things.
8
What Data were used in the Report? Waterandsuspendedsedimentqualitydataforthisreportwereobtainedfromthreelong-termsamplingsiteslocatedontheSlaveRiver.Theseinclude:
• TheSlaveRiveratFortSmith(mid-river)samplingsiteledbyAANDC.Thisprogramiscomprisedoftwoparts:theSlaveRiverEnvironmentalQualityMonitoringProgram(SREQMP;1990-1995),andtheFollow-UpStudy(2000-2010).
• TheSlaveRiveratFortSmith(shore)samplingsitewhichhasbeenledbyAANDCsince1982.
• TheSlaveRiveratFitzgeraldsamplingsitewhichhasbeenledbyEnvironmentCanadasince1960.
Flowdatawereobtainedfromthehydrometric(flow)monitoringstationlocatedontheSlaveRiveratFitzgeraldwhichhasbeenoperatedbyEnvironmentCanada(WaterSurveyofCanada)since1960.
ThesefederalgovernmentmonitoringsiteswereestablishedtocharacterizethewaterqualityandquantityconditionsinthesectionoftheSlaveRiverneartheprovincial/territorialboundary.
So how is the Water Quality in the Slave River?TheSlaveRiverhasanaveragepHof7.9whichistypicaloffreshwaters.Therivercontainsmoderateamountsofdissolvedsolidsandisconsidered‘moderatelyhard’.Calciumandmagnesiumdissolvedinwaterarethetwomostcommonmineralsthatmakewater“hard.”Harderwatermeansthatyoumightneedmoresoaptomakealatherwhenwashingdishes.
Phosphorus,anessentialnutrientforthegrowthofaquaticplantsandalgae,playsanimportantroleintheoverallproductivityoffreshwaterecosystems(i.e.,numberoffish,aquaticanimals,etc.).TotalphosphoruslevelsintheSlaveRiverrangefrom0.006to4.67milligramsperlitre(mg/L).Asthemedianvalueoftotalphosphorusis0.1mg/L,theSlaveRiverisconsideredeutrophic(i.e.,highlevelsofnutrientsandplantgrowth,lowwaterclarity).AnalysisofSlaveRiverwaterdatarevealedanincreasingtrendinphosphorussince1974.Continuedsamplingandobservationsareimportanttoassessphosphoruslevelsgiventhatlandusershaveobservedmorealgaeontherocksandinfishingnets,anddenserwillowsandotherplantsaregrowingalongtheshore.
SulphateandsodiumconcentrationshavealsoincreasedintheSlaveRiverovertime,whiletotaldissolvedsolidslevelshavedecreased.Furtherworkisrequiredtodeterminetheecologicalsignificanceofthesetrends.Itisimportanttonotethatguidelinesforallroutineparameterswerenotexceeded.
Slave River shoreline
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
9
TheSlaveRiverhashighlevelsofsuspendedsediment.Thisismainlyduetothefactthatitstwomajortributaries,theAthabascaandPeaceRivers,flowthroughtheInteriorPlains.Thisisanareathatisunderlainwithsedimentaryrocksandsoilsthatareeasilyerodedintolittlebitsthatgetcarriedbytheriver.SuspendedsedimentvaluesintheSlaveRiverrangefrom3to5600mg/L,withanaverageof240mg/L(Figure2).Inthisgraph,thesedimentloadsoftheSlaveRiverarecomparedtotwootherhighlysedimentladenriversintheNWT,thePeelandLiardRivers,aswellasone‘sediment-free’river,theYellowknifeRiver.TheYellowknifeRiverflowsprimarilythroughthebedrockofthePrecambrianShield;riversintheseregionsarerelativelyfreeofsediment.
Sedimentloadaffectsmetallevels.Riversthatcarrylargeamountsofsedimenttendtohavehigherlevelsofmetals.Thisisbecausemetalscanadsorb(i.e.,stick)tosedimentparticles(Figures3and4).ThehighlysedimentladenPeel,LiardandSlaveRivershavehigherlevelsofmetalsthantherelatively‘sediment-free’YellowknifeRiver.
Metalsinwaterexistinanumberofsoluble(i.e.,dissolved)andinsoluble(i.e.,attachedtoclaysororganicmatter)forms,withthedissolvedformbeingmoreavailableforuptakebyaquaticanimalsandfish.
ThedissolvedlevelsofmetalsintheSlaveRiverareconsiderablylowerthanthetotallevels(Figure5).
0
50
100
150
200
250
300
Slave River Peel River Liard River Yellowknife River
Conc
entr
ation
(mg/
L)
Slave River
Peel River
Liard River
Yellowknife River
Data Sources: Slave (n=210;); Liard(n=201); Peel(n=168) (1980-2010, Environment Canada); Yellowknife(n=228) (1987-2010, AANDC)
Figure 2: Comparing the Average Concentrations of Total Suspended Solids between the Slave, Peel, Liard and Yellowknife Rivers
Same water, one filtered, one not filtered.
Dissolved metal samples are filtered before analysis and include the metals in the water that you cannot see (similar to salt). Total metal samples are not filtered before analysis and include the dissolved metals as well as the metals that are attached to the suspended sediments.
10
0
1000
2000
3000
4000
5000
6000
7000
8000
Aluminum Iron
Conc
entr
ation
(ug/
L)
Slave River
Peel River
Liard River
Yellowknife River
Data Sources: Slave, Liard, Peel (1980-2010, Environment Canada); Yellowknife (1987-2010, AANDC).Note: number in parentheses represents the total number of samples collected between the dates indicated; red dotted line represents the Guideline for the Protection of Aquatic Life for Total Iron; Total Aluminium currently does not have a guideline.
(77)(74) (106) (176) (107) (212)(102) (101)
Figure 3: Comparing Average Concentrations of Total Aluminum and Total Iron between the Slave, Peel, Liard and Yellowknife Rivers
0
1
2
3
4
5
6
7
8
9
10
Arsenic Chromium Copper Lead Vanadium
Conc
entr
ation
(ug/
L)
Slave River
Peel River
Liard River
Yellowknife River
Data Sources: Slave, Liard, Peel (1980-2010, Environment Canada); Yellowknife (1987-2010, AANDC). The number in parentheses represents the total number of samples collected between the dates indicated; red dotted line represents the Guidelines for the Protection of Aquatic Life; note that the guidelines for copper and lead are corrected for water hardness (the guidelines were calculated based on average water hardness levels).
(102) (209)(211)(211)(25) (78) (147) (147) (136)(39) (186)(107) (186) (162)(176)(124) (186) (186) (220)(37)
Figure 4: Comparing Average Concentrations of Total Arsenic, Total Chromium, Total Copper, Total Lead and Total Vanadium between the Slave, Peel, Liard and Yellowknife Rivers
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
11
1 Long term trends in metals were assessed for total aluminum, chromium, copper, iron, lead, manganese, molybdenum, nickel, vanadium and zinc, as these had an adequate dataset.
0
500
1000
1500
2000
2500
3000
0
0.5
1
1.5
2
2.5
3
Arsenic Chromium Lead Aluminum Iron
Alu
min
um
an
d Ir
on
Co
nce
ntrati
ons
(ug/
L)
Ars
enic
, Ch
rom
ium
an
d L
ead
C
onc
entr
atio
ns
(ug/
L)
Dissolved Concentrations Total Concentrations
Figure 5: Average Concentrations of Total and Dissolved Arsenic, Chromium, Lead, Aluminum and Iron from the Slave River at Fitzgerald (2006-2010, n=24)
MostmetalsintheSlaveRiverareattachedtothesuspendedsedimentssuggestingthattheyarelessavailabletoaquaticlife.
MetallevelsintheSlaveRiverwerecomparedtoguidelinesfortheprotectionofaquaticlife.Totalmetalssuchascadmium,chromium,copper,ironandleadwerehigherthantheirrespectiveaquaticlifeguidelinesmorethan25%ofthetime.Othertotalmetals,suchasarsenic,barium,manganese,nickel,selenium,silver,vanadiumandzincexceededtheirrespectiveaquaticlifeguidelineslessfrequently(lessthan25%ofthetime).Todate,totalmetalsincludingantimony,beryllium,cobalt,molybdenum,thalliumanduraniumhavenotexceededtheaquaticlifeguidelines.
Whenaguidelineisexceededitdoesnotnecessarilymeanthatthelevelsofmetalsareaconcernorthatanoutsidefactorisaffectingthewater.TheavailableguidelinestoassesswaterqualityintheNWTaregenericguidelines.Theseguidelinesaredevelopedforawiderangeofwaterqualityconditionsbutarenotnecessarilyspecifictolocalwaterqualityconditions.Forexample,iftheriverisnaturallyhighinmetals,thefishhavelikelyadaptedtothoseconditions.If,however,themetalsarehigherthannaturallevels,fishandaquaticlifecouldbeatrisk.Todetermineifthelevelsofmetalshavechangedovertheyears,thisstudyexaminedlongtermtrendsinmetalsovertime.Ofthe10metals1forwhichtrendswereassessed,onlymolybdenumshowedasignificantdecreasingtrendandonlyinthespring.Furtherstudyisrequiredtounderstandthesignificance,ifany,ofthistrend.
Insomecases,whengenericguidelinesareusedtoassessSlaveRiverwaterquality,theguidelinesareexceededasaresultofhighsedimentloads(e.g.duetometalsattachingtosuspendedsediment).Thisisillustratedwithtotalironlevelswhichrangefrom59to128,000microgramsperlitre(ug/L);over90%ofthevaluesexceedtheaquaticlifeguidelineof300ug/L(Figure6).Asthereisnolongtermtrendintotaliron,itislikelythattheironlevelsare
12
normalandthatahigherwaterqualityobjectivemaybemoreappropriatetoassessironlevelsintheSlaveRiver.
However,metallevelsintheSlaveRiveraresometimesmuchlowerthanthegenericguideline.Thisscenarioisshownwithtotalarseniclevelswhichrangefrom0.3to15ug/L;withabout6%ofthevaluesexceedingtheaquaticlifeguidelineof5ug/L(Figure7).Insuchinstances,developmentofalowersite-specificwaterqualityobjectivemaybeappropriate.
Itisimportanttonotethatanalysisofthedataalsoidentifiedafewinstanceswherethedissolvedconcentrationofametalexceededthetotalmetalguideline(e.g.,cadmium,chromium,copperandiron).Itisimportanttokeepmonitoringandassessingthesemetalssinceitisthedissolvedformwhichisgenerallymoreavailabletofish.Toprovideadditionalinsightonthisobservation,trendanalysiswillbeconductedonceenoughdissolvedmetalsdatabecomesavailable.
When generic guidelines are used, they can sometimes be either over-protective or under-protective. This is the reason why site-specific water quality objectives are needed. These objectives would allow for a better assessment of the substances in the Slave River and provide a relevant set of benchmarks against which future data can be compared. Also, where generic guidelines do not currently exist for certain substances of concern (e.g., phosphorus), the development of site-specific water quality objectives would help to fill these gaps.
10
100
1000
10000
100000
1000000
1980 1984 1988 1992 1996 2000 2004 2008 2012
Slave River at Fitzgerald Slave River at Fort Smith
CCME Freshwater Aquatic Life Guideline (300 ug/L)
Figure 6: Total Iron Concentrations in the Slave River (1980-2010)
0
2
4
6
8
10
12
14
16
1980 1984 1988 1992 1996 2000 2004 2008
Slave River at Fitzgerald Slave River at Fort Smith
CCME Freshwater Aquatic Life Guideline (5 ug/L)
Figure 7: Total Arsenic Concentrations in the Slave River (1982-2010)
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
13
Are there Persistent Organic Pollutants (POPs) in the Water or Suspended Sediments of the Slave River? TheSlaveRivermonitoringprogramsatFitzgeraldandFortSmithincludetheanalysisofwaterandsuspendedsedimentsamplesforhuman-madecontaminantssuchaspesticides,chlorophenols,dioxins,furansandPCBs.
Wherepossible,resultswerecomparedtoCCMEguidelinesfortheprotectionofaquaticlife.Guidelinesdonotexistforsuspendedsediment;thereforecomparisonsweremadetobottomsedimentguidelines.SuspendedsedimentscollectedfromtheSlaveRiverarecomposedmainlyofclayandsilt(fineparticles).Asbottomsedimentsalsocontaincoarseparticles,therearelimitationswhencomparingsuspendedsedimentvaluestobottomsediment.
Ofthe11pesticideswhichweredetectedinwatersamplescollectedfromFitzgerald,nineweredetectedonlyonce,andnonehavebeendetectedsince1986.Allvalueswerebelowguidelines.PesticideswerenotdetectedinthewaterorsuspendedsedimentatFortSmith,however,lowdetectionlimitswerenotalwaysavailable;futuremonitoringwithlowdetectionlimitswillprovideadditionalinsightintosampleresults.
SomechlorophenolcompoundsweredetectedatlowlevelsinboththewaterandsuspendedsedimentsamplescollectedfromtheSlaveRiveratFortSmithduringtheSREQMP(1990-1995).Allchlorophenolvaluesinwaterwerebelowguidelines(Note:therearenosedimentguidelinesforchlorophenols).NoneofthesecompoundsweredetectedintheSlaveRiveratFortSmithduringtheFollow-UpStudy(2000-2010).Thisapparentdecreaseinchlorophenolscouldbeduetothestricterlimitsforthepulpandpaperindustry,whichwereimposedbytheCanadianGovernmentinthe1990s.However,insomecasestheverylowdetectionlimitsobtainedduringtheearlierstudyarenotavailabletoday,sofurthermonitoringisrequiredtoconfirmthesefindings.
Slave River water and suspended sediment samples have been analyzed for contaminants that are known to be associated with upstream development. Overall, fewer organic compounds, and at lower levels, were found in the water and suspended sediment samples during the Follow-Up Study (2000-2010) than in the SREQMP (1990-1995). Monitoring will continue. Setting appropriate detection limits is important for future studies.
Pelicans below Rapids of the Drowned
It should be noted that for some organic parameters, detection limits were higher in the Follow-Up Study than the SREQMP. According to the laboratory used to analyze the organics in the river samples, the rules that govern laboratory reporting have changed. Laboratories must now report values with a much higher level of certainty than what was needed in the past. As such, the very low detection limits achieved during the SREQMP are not available today. In some cases, this makes comparison of results difficult, however, further monitoring will allow for trend analyses to be conducted which will help determine if trends are being observed.
14
AfewdioxincompoundswerefoundinthesuspendedsedimentduringboththeSREQMPandFollow-UpStudyatlowlevelsandwellbelowanyavailableguidelines(Note:Dioxinsarenotmeasuredinwater).Levelsweresimilarduringbothstudyperiods.Thepresenceofthesecompoundscouldindicateatmosphericorpointsources.Onecompoundwhichhasbeenlinkedtopulpmilleffluent(2,3,7,8–TCDF)wasdetectedatlowerlevelsandlessfrequently(onlyonetime)duringtheFollow-UpStudy.Thisapparentdecreasecouldalsobelinkedtotheregulationchangesforpulpmills.Monitoringofthesecompoundswillcontinue.
PCBswerenotdetectedinanywatersamplesusingstandardtests.Ononeoccasion,whenverylowdetectionlimitswereused,PCBsweredetectedinthesuspendedsediment.Theobservedvalueswereextremelylow(800Xlessthantheguideline).
Hydrocarbons Hydrocarbonshavebothnaturalandhumanmadesources.PAHshavebeendetectedinboththewaterandsuspendedsedimentsamplescollectedfromtheSlaveRiver.
AllPAHcompoundsdetectedinwaterhavebeenatlevelswhicharelowerthantheaquaticlifeguidelines.SomePAHcompoundsinsuspendedsedimentexceededbottomsedimentguidelines.However,intheFollow-UpStudy,fewerPAHcompoundswereaboveguidelinesandtherangesofvaluesabovedetectionwerelower.Agoodexampleofthisisnaphthalene(Figure8),withconcentrationsrangingfrom10-580nanogramspergram(ng/g)duringtheSREQMPandfrom10-50ng/gduringtheFollow-UpStudy.
Aug
ust-
91
Sept
embe
r-91
June
-92 Se
ptem
ber-
92
Janu
ary-
93
June
-93
Aug
ust-
93
Janu
ary-
94
Mar
ch-9
4
June
-94
Sept
embe
r-94
Janu
ary-
95
Mar
ch-9
5
Sept
embe
r-00
Febr
uary
-01
June
-01
June
-03
June
-06
Aug
ust-
06
Mar
ch-0
7 May
-07
Sept
embe
r-10
1
10
100
1000
Conc
entr
ation
(ng/
g)
Comparing the Concentrations of Naphthalene in the Suspended Sediments of the Slave River between the SREQMP (1990-1995) and the Follow-Up Study (2000-2010)
CCME TEL Guideline(34.6 ng/g)
Figure 8: Comparing the Concentrations of Naphthalene in the Suspended Sediments of the Slave River between the SREQMP (1990-1995) and the Follow-Up (2000-2010)
A ng/g is one billionth of a gram or part per billion (ppb). To think of it in a different way, a ppb is like 1 second of about 32 years.
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
15
Naphthaleneisahydrocarbonmadefromcrudeoilorcoaltar.Itisalsoproducedwhenthingsburnandisfoundincigarettesmoke,carexhaust,andsmokefromforestfires.Itisusedasaninsecticideandcanbefoundinmothballs.Whileitisimportanttocontinuetomonitorforparameterssuchasnaphthalene,whichseemtobepresentintheriverallthetime,itisalsoimportanttoensurethatmonitoringeffortsarefocussedonemergingPAHcompounds,suchasalkylatedPAHs,thathavebeenspecificallyassociatedwithupstreamactivities.Thesecompoundswereaddedtothemonitoringprogramin2007;andhavebeendetectedatlowlevelsinthetwosamplescollected.AlthoughtherearecurrentlynoCanadianguidelinesforalkylatedPAHs,theresultsfromthesampleswerewellbelowtheUnitedStatesEnvironmentalProtectionAgency(USEPA)benchmarkestablishedfortheprotectionofbottom-dwellingorganisms(bugs,worms,etc.).
Startingin2001,suspendedsedimentsampleswereanalyzedforanexpandedlistofPAHcompounds,whichallowedforcomparisontototalPAHguidelines2forbottomsediment.TotalPAHlevelsinSlaveRiversuspendedsedimentswerefoundtobeatleasttentimeslowerthanthisguideline,whichwasestablishedfortheprotectionofbottom-dwellingorganisms(Figure9).
February-01
June-01
June-03 June-06
August-06
March-07
May-07
September-10
0
50
100
150
200
250
300
350
400
450
Tota
l PAH
(ng/
g)
Figure 9: Total PAHs Concentrations in the Slave River Suspended Sediment Samples (2001-2010)
As there is no national guideline available for PAH, a comparison to the Ontario guideline is illustrated here. The levels in the Slave River suspended sediment samples are much lower than the Ontario total PAH bottom sediment guideline of 4000 ng/g established for the protection of bottom-dwelling organisms.
2 In the absence of a national guideline for total PAHs in bottom sediments, the Ontario guideline was used.
16
Can I Drink the Water?InCanada,theresponsibilityformakingsuredrinkingwatersuppliesaresafeissharedbetweentheprovincial,territorial,federalandmunicipalgovernments.Theday-to-dayresponsibilityofprovidingsafedrinkingwatertothepublicgenerallyrestswiththeprovincesandterritories,whilemunicipalitiesusuallyoverseetheoperationsofthetreatmentfacilities.
Inconjunctionwiththeprovincesandterritories,HealthCanadadevelopedthe“Guidelines for Canadian Drinking Water Quality.”TheseguidelinesareusedbyeveryjurisdictioninCanadaandarethebasisforestablishingdrinkingwaterqualityrequirementsforallCanadians.
However,theseguidelinesareintendedtobeappliedtotreatedtapwater–notsourcewatersuchastheSlaveRiver.Since“CanIdrinkthewater?”isacommonandimportantquestion,theresultsoftheSlaveRiversurfacewatersamplingwerecomparedtoCanadiandrinkingwaterguidelinesasageneralassessmentofthiswaterfordrinking.Asexpected,duetothehighsedimentloadsoftheSlaveRiver,totalmetalsdidnotalwaysmeettheguidelines.However,whenthemetalconcentrationsinthefilteredwatersample(dissolvedmetals)werecompared,thedrinkingwaterqualityguidelineswerealwaysmet.
AlthoughwatersintheCanadianoutdoorsaregenerallyofexcellentquality,peopleshouldalwaysbepreparedtoboilordisinfectalldrinkingwater.
Itisveryimportanttonotethatnosurfacewatercanbeguaranteedtobesafefordrinkingwithouttreatment.HealthCanadaandtheGovernmentoftheNorthwestTerritoriesrecommendheatastheoldest,safestandmosteffectivemethodofpurifyingwater.Bringthewatertoarollingboilforatleastoneminutetoremovebacteria.Ifthewateriscloudy,likeitisintheSlaveRiversometimes,itshouldbefilteredbeforeboiling.Filtrationofsourcewaterpriortodisinfectionwillprovideadditionalprotection.
The surface water of the Slave River is safe for drinking* and swimming.
* After filtering and boiling the water for at least one complete minute. Additional information on drinking water in the Canadian outdoors and/or information on drinking water sources in the NWT can be found at: http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/outdoor-plein_air-eng.php and http://www.maca.gov.nt.ca/operations/water/homepage.asp.
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
17
Slave River Flows
FlowintheSlaveRiverisgreatlyinfluencedbythePeaceRiver,whichcontributesabout60%oftheSlaveRiverflowvolume.BeforetheW.A.C.BennettDamwasbuilt,flowsintheSlaveRiverbegantodecreaseinthefall,reachedaminimuminthewinterundericeandthenpeakedinthespringduringandjustafterbreakup(Figure10).Whilethispatternisstillobserved,followingconstructionofthedam,thehydrographhasbeendampened,inthatthewinterflowsarehigherandpeakflowsarelower(Figure10).Infact,sinceflowregulation,flowsinthewinterhavebeenincreasedby75%,andflowsinthespringhavebeenreducedby20%.ItisimportanttonotethatthetotalamountofwaterflowingintotheNorthwestTerritorieshasnotchanged,justthetimingofwhenthewaterarrives.
OtherchangesintheflowoftheSlaveRiverhavebeenobserved.Forexample,highfreshetpeaksweregenerallyexperiencedinJunebeforedamconstruction,butarenowofteninMay(Figure11).Atrendtowardmorefrequentpeaksontheannualhydrographshasalsobeenidentifiedandsecondarypeaksnowappearinsomeyearsduringwinter.Thesechangesmaybeduetoflowregulation,oranincreaseinclimaticvariabilityinthewatershed.
In2010,recordlowwaterlevelswereexperiencedontheSlaveRiver,onGreatSlaveLakeandintheupperMackenzieRiver.ManyofthetributariestotheWillistonLakeReservoirbehindtheW.A.C.BennettDamalsoexperiencedrecordlowsthatyear.ThissuggeststhatthelowwaterlevelsintheNWTthatyearwerelikelyduetolowsnowpackandrainfallintheupperportionoftheSlaveRiverwatershed.
Thisreportalsoexaminedlongtermtrendsinflow.Inadditiontolookingatannualtrendsovertime,eachseasonwasexaminedseparately.Nosignificanttrendswerefoundduringthespringorovertheentireyear(Figure12aandb).However,significantdecreasingtrendswere
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Flow
(m³/s
)
Pre-Dam, 1960-1967 Post-Dam, 1972-2010
Figure 10: Mean annual hydrographs of the Slave River at Fitzgerald for pre-dam (1960-1967) and post-dam (1972-2010) years (Water Survey of Canada – 07NB001). Adapted from MRBB, 2003.
18
foundinthesummerandfallflows,andasignificantincreasingtrendwasfoundinwinterflows(Figure12c,dande).Inotherwords,itseemsasthoughtheamountofwaterduringthesummerandfallflows,andasignificantincreasingtrendwasfoundinwinterflows(Figure12).Inotherwords,itseemsasthoughtheamountofwaterduringthesummerandfallaregettingprogressivelylowereachyear.Additionally,theamountofwaterinthewinterappearstobeincreasingeachyear.Thesetrendsmaybeduetoflowregulation,butmayalsobeduetoclimatechangeinthewatershed.Furtherstudyisrequiredtounderstandtheecologicalsignificanceofthesetrends.
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Flow
(m³/s
)
1967 (pre-dam) 2007 (post-dam)
Figure 11: Examples of annual hydrographs of the Slave River at Fitzgerald for a pre-dam (1967) and a post-dam (2007) year (Water Survey of Canada – 07NB001).
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1971 1981 1991 2001 2011
Med
ian
Flow
(m3 /s
)
Annual (a)
Figure 12a: Medians of 1972-2010 annual and seasonal Slave River daily flows at Fitzgerald (WSC Hydat, 2010). Solid lines indicate 95% confidence in the trend; dashed lines indicate trends with less than 95% confidence.
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
19
Figure 12b: Medians of 1972-2010 annual and seasonal Slave River daily flows at Fitzgerald (WSC Hydat, 2010). Solid lines indicate 95% confidence in the trend; dashed lines indicate trends with less than 95% confidence.
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1971 1981 1991 2001 2011
Med
ian
Flow
(m3 /s
)
Spring (b)
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1971 1981 1991 2001 2011
Med
ian
Flow
(m3 /s
)
Summer (c)
Figure 12c: Medians of 1972-2010 annual and seasonal Slave River daily flows at Fitzgerald (WSC Hydat, 2010). Solid lines indicate 95% confidence in the trend; dashed lines indicate trends with less than 95% confidence.
20
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1971 1981 1991 2001 2011
Med
ian
Flow
(m3 /s
)Fall (d)
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1971 1981 1991 2001 2011
Med
ian
Flow
(m3 /s
)
Winter (e)
Figure 12d: Medians of 1972-2010 annual and seasonal Slave River daily flows at Fitzgerald (WSC Hydat, 2010). Solid lines indicate 95% confidence in the trend; dashed lines indicate trends with less than 95% confidence.
Figure 12e: Medians of 1972-2010 annual and seasonal Slave River daily flows at Fitzgerald (WSC Hydat, 2010). Solid lines indicate 95% confidence in the trend; dashed lines indicate trends with less than 95% confidence.
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
21
Changes in Water Quality due to Changes in FlowWaterqualityandquantityareverycloselylinked.Innaturalunregulatedrivers,dissolvedsubstancesaretypicallyhigherduringthewinterbecausealargerpercentageofwatercomesfromgroundwaterinflows.IntheSlaveRiver,however,thispatternisnotobserved.Manyofthedissolvedsubstances(totaldissolvedsolids,potassium,sulphate,fluoride,dissolvedorganiccarbon,phosphorus)havehigherconcentrationsinthespringandsummer,thaninthewinter.AnexampleisshowninFigure13.Forotherdissolvedsubstances(specificconductance,alkalinity,calcium,magnesium,sodium,hardness,ammonia),concentrationsintheSlaveRiverweresimilaramongseasons.AnexampleisshowninFigure14.ThesechangesmaybelinkedtothealteredflowregimeoftheSlaveRiverduetoupstreamflowregulationofthePeaceRiver;higherobservedwinterflows,themixingeffectsofLakeAthabascaandWillistonLake;and/orthepotentialinfluenceofclimatechange.
Fortotaldissolvedsolids,alkalinityandhardness,thisseasonalpatternofhigherlevelsinthespringandsummerascomparedtothewinterappearstobeoccurringasfardownstreamasthemouthoftheSlaveRiver(i.e.justupstreamofGreatSlaveLake).
Furtherstudyisberequiredtodetermineiftheseseasonalchangesinwaterquality,whichcanbelinkedtochangesinquantity,arehavinganyecologicaleffectsontheSlaveRiveraquaticecosystem.
0
50
100
150
200
250
300
350
400
450
Low Flows High Flows Low Flows High Flows Low Flows High Flows
Slave River Peel River Liard River
Tota
l Dis
solv
ed S
olid
s (m
g/L)
Comparing the Levels of Dissolved Solids during Periods of High Flow and Low Flow between the Slave, Peel and Liard Rivers
For the purposes of this illustration, lows flows constitute the TDS values reported for the months of January and February, whereas high flows constitute the months of May and June (Data Source: 1993-2010; Environment Canada).
Box and Whisker Plot: upper /lower whisker = maximum/minimum values; coloured section of boxes represents 50% of the data; the median value is represented by the horizontal lline and the average is represented by the asterisk.
Figure 13: Comparing the Levels of Dissolving Solids during Periods of High Flow and Low Flow between the Slave, Peel and Liard Rivers
22
Slave River upstream of Fitzgerald
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
50
100
150
200
Low Flows High Flows Low Flows High Flows Low Flows High Flows
Slave River Peel River Liard River
Alk
alin
ity (m
g/L)
Comparing Alkalinity Levels during Periods of High Flow and Low Flow between the Slave, Peel and Liard Rivers
For the purposes of this illustration, lows flows constitute the alkalinity values reported for the months of January and February, w hereas high flows constitute the months of May and June (Data Source: 1980-2010; Environment Canada).
Box and Whisker Plot: upper /lower whisker = maximum/minimum values; coloured section of boxes represents 50% of the data; the median value is represented by the horizontal lline and the average is represented by the asterisk.
Figure 14: Comparing Alkalinity Levels during Periods of High Flow and Low Flow between the Slave, Peel and Liard Rivers
23
What happens next? InconjunctionwiththeEnvironmentCanadamonitoringprogramsatFitzgerald,theAANDCmonitoringprogramatFortSmithprovidesalargeamountofdatafromtheSlaveRiver.Theseprogramsarecriticaltobetterunderstandchangesintheaquaticenvironmentandformthebasisofmanydifferentresearchandmonitoringinitiatives.
AANDCiscontinuingtocarryouttheSlaveRivermonitoringprogramthroughthecollectionofwaterandsuspendedsedimentsamples.TheDepartmentwillworkwithEnvironmentCanadatoassessSlaveRiverwaterqualityandquantitydatawhennewdatabecomeavailable.
TheDepartmentwillalsocontinuetobeactivewithinotherregionalmonitoringinitiatives,suchastheSlaveRiverandDeltaPartnership.Thispartnership,consistingofmembersfromAboriginal,federalandterritorialgovernments,AuroraCollegeandcommunitiesalongtheSlaveRiver,hasresultedinseveralinitiatives.Theseincludecommunity-basedmonitoringworkshops,SlaveRiverDeltasedimentsamplingandtheSlaveRiverfishsamplingprogram.Underthisinitiative,passivesamplershavebeenrecentlydeployed
intheSlave,AthabascaandPeaceRivers.Thesesamplersremainintheriverforuptoonemonthandwillbeanalyzedforpersistentorganicpollutantsandmetals.Inadditiontotheseefforts,Environment
CanadahasimplementedanexpandedoilsandsmonitoringprogramthatincludestheSlaveRiverandSlaveRiverDelta.Collaboratively,theseresearchandmonitoringinitiativeswillsupporteachothertoexpandtheknowledgeandunderstandingoftheSlaveRiveraquaticecosystem.
Overall,theSlaveRiverreportprovidesanoverviewofthedatacollectedinpastyears.Monitoringwillcontinueand,wherepossible,improvementstothemonitoringprogramwillbemade.IncorporatingadditionaldataandinformationwillhelpassessanyenvironmentalchangeintheSlaveRiverovertime.Itisimportantthatallmonitoringprogramsattempttocollectdatainaconsistentmanner.Consistentdatacollectionandsharing,includingacrossjurisdictions,canbeextremelyusefulasitwillallowformorethoroughwaterqualityassessmentsandprovideabetterunderstandingofchangeinthewatershed.
Fort Smith Community Workshop, March 2011
24
Water and Suspended Sediment Quality in the Transboundary Reach of the Slave River
Formoreinformation,pleasecontactJuanettaSanderson(867-669-2653)orAndreaCzarnecki(867-669-2509)withtheWaterResourcesDivisionof
AboriginalAffairsandNorthernDevelopmentCanada.
http://www.aandc.gc.ca/eng/1100100022930/1100100022931
November2012
Continued monitoring by water partners is important to ensure the health of the Slave River
in the Northwest Territories.