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66J / AN IN-PLACE POLLUTANTS STUDY OF THE OTONABEE RIVER AND RICE LAKE AUGUST 1992 Environment Environnement iM''^ Ontario ISBN 0-7729-8010-1 AN IN-PLACE POLLUTANTS STUDY OF THE OTONABEE RIVER AND RICE LAKE Report prepared by: R. Jaagumagi and S. Petro Watershed Management Section Water Resources Branch Ontario Ministry ofthe Environment AUGUST 1992 © Cette publication technique n'est disponible qu'en anglais. Copyright: Queen's Printer for Ontario, 1992 This pubhcation may be reproduced for non-commercial purposes with appropriate attribution. PIBS 1663 Log 91-2309-052 ACKNOWLEDGEMENTS ThisstudywascoordinatedbythestaffofMOECentralRegion.Theauthorsalsogratefullyacknowledge theinputofW.Scheider.D.Persaud,A.Hayton andS.Maudewhoreviewedthe draftreport, D.Persaudwho coordinatedthestudy,andG.Hitchin(OMOEWaterResourcesBranch)whocoordinatedthefieldwork.The staffofthe MOE LaboratoryServices Branch (OMOE) providedchemical analysis ofthe sediment and water samples. Barringer Magenta Ltd. provided geochemical fractionation data and OceanChem Group provided additional analysis ofbiota tissue levels. The authors also wish to thank Tim Fletcher, Lisa Smith and Anna Toskaswhopreparedthe tables, andTim Fletcherwhopreparedthe figures and assisted inthe analysis ofthe data. SUMMARY A 1987 sediment and benthic survey of the Otonabee River and Rice Lake has identified potential concerns associated with point source discharges of contaminants in Peterborough. The major findings are summarized below. 1. Bottomwateranalysesshowednodiscernibleconcentrationsofcontaminantsotherthanthoseassociated with the Peterborough Sewage Treatment Plant discharge. The study also indicated that release of sediment-bound contaminantsto thewater columnwasnot a major concern. 2. Concentrationsofmetalsinthesedimentswerehighthroughoutthesystem.Concentrationsofcopper, lead andzinc increased above upstream levels at Peterborough, and again inRice Lake.A number of sourcesare likelycontributingtotheseelevatedlevels.Depositionofsuspendedmaterialin Rice Lake fromupstreamsourcesisthemajorcontributingfactortohighersedimentcontcuninantconcentrations inthelake. 3. Concentrations of PCBs in river sediments were very high at Peterborough and decreased further downstream.ConcentrationswerehighinRiceLake, suggestingthatmaterialfrom upstreamhasbeen carrieddownstreamanddepositedinthedeeperpartsofthelake. Concentrationsinbenthicorganisms weregenerallylowandcouldnotbespecificallyrelatedtosedimentsources,thoughotherstudies,e.g., clams,haveshownthattissueresiduesreflectthesedimentdistributionofPCBs.Thehydrophobicnature ofPCBssuggests that availabilityfrom the sedimentswould be lowand that thewatercolumn aswell as ingestion ofcontaminated foodsourcesmaybe the most significant routes ofuptake for PCBs. 4. SedimentPAHconcentrationswereveryhighinPeterboroughanddecreasedrapidlydownstream.While sourcescannotbedeterminedanoldcoalgasificationcomplexinPeterboroughaswellasurbanrunoff are amongpossiblesourcesthatwouldwarrant investigation. 5. Tissue residues ofcontaminants in benthic invertebrates and fish were low for metals and generally belowdetectionlimitsfororganiccompounds(PAHswerenotanalyzed)otherthanPCBsandindicate that most compoundswerepresentinthesediment inunavailableforms. Littleor nobioaccumulation could be attributed directlyto sediment sources. 6. Sediment bioassays indicated that therewas noacutetoxicityfrom sediment associated contaminants, though mortalityand uptake ofsome contaminants (mainlymetals) was higher at certain stations. 7. Benthiccommunityresponsesuggeststhatthedepositionoforganicmatteristhesinglemostimportant factor affectingbenthic invertebrate distribution. No clear impact ofcontaminants could be detected on the benthic community. TABLEOFCONTENTS Summary ii 1. Introduction 1 2. Methods 1 3. Results 2 3.1 Bottom Water 2 3.2 Sediments 2 3.3 Biota Contamm;mt Residues 5 3.3.1 Benthic Invertebrates 5 3.3.2 Fish 8 3.4 Sediment Bioassays 9 3.5 BenthicInvertebrateSurvey 10 4. Discussion 12 5. Conclusions 14 6. Recommendations 15 7. Literature Cited 15 8. Figures Appendix 1 9. Tables Appendix2 LISTOFFIGURES Figure No. 1 Location ofSamplingStations 2 Sediment MetalConcentrations in the Otonabee River- RiceLake system 3 Geochemicalfractionation ofsediment metals 4. Sediment PAH concentrations. 5. Sediment PCB concentrations. 6. Sediment - biota metal concentrations 7. Benthic invertebrate - fish tissue residues 8. Sediment BioassayTissue Residues - Metals 9. Distribution ofmajor benthic invertebrategroups