Post-remediation monitoring of the Northern  Wood Preservers Inc. Site in Thunder BayHarbour: Results from the 2009 Biomon...
EXECUTIVE SUMMARYIn 2009, the Environmental Monitoring and Reporting Branch (EMRB) of the Ministry of theEnvironment (MOE)...
maximum exposure, especially in this case as invertebrates in the harbour can likely avoid thedistinct lenses of contamina...
ACKNOWLEDGMENTSField collection of samples was conducted by Chris Mahon, Steve Petro and Emily Awad.Thank you to Jennifer ...
Table of ContentsExecutive Summary...........................................................................................
FiguresFigure 1. Location of 2009 (a) sampling sites and (b) reference sites in     21Thunder Bay Harbour, near the NWP si...
Figure 15. Median abundance (a) and richness (b) of benthic assemblages      34from sites sampled in 2009 from the Thunder...
BACKGROUNDIn 2009, the Environmental Monitoring and Reporting Branch (EMRB) of the Ministry of theEnvironment (MOE) undert...
permeability of the clay barrier (Santiago et al., 2003). Remediation of the site began in 1997and the habitat features we...
(LaSB method ORGC3012), particle size (LaSB method PART3328), nutrients (LaSB methodTNP3116), and metals (LaSB method MET3...
(Beckvar et al., 2000; Kauss & Hamdy, 1985). The mussels were stored in aerated roomtemperature Balsam Lake water in 22 L ...
LEL is the level of contamination that can be tolerated by the majority of sediment-dwellingorganisms, while the SEL is th...
site and year combination. There are no provincial or federal PAH guidelines against whichmussel concentrations can be com...
parameters significant at p≤0.05, as determined by Monte Carlo permutation tests, wereretained in the RDA (Lepš and Šmilau...
samples, the values reflect both particulate and dissolved aluminum concentrations, and arelikely biased high.Iron also ex...
due to those compounds with ≤ three benzene rings (i.e. phenanthrene, pyrene, andfluoranthene, which are dominant in creos...
Similar levels of most metals between reference and non-reference sites have been reportedsince the mid-1990s (Jaagumagi e...
elevated in 2009 at NOR4 and NOR8 and the Kruskal-Wallis test showed a significantdifference among years (p<0.05), the dif...
In the Fathead Minnow bioaccumulation test, mean survival was significantly lower than thereference site at NOR6 (40±34%)....
NOR4 and NOR6. At NOR8, which showed reduced survival in the 2004 toxicity bioassays,there were much greater increases in ...
sites (p>0.05), median abundance at NOR7 (71 individuals) was significantly less thanabundance at NOR10 (757.5 individuals...
Benthic OrdinationsPCA on the relative abundances of the eight common benthic families explained 96% of thevariation in be...
PAH concentrations continue to be elevated above provincial sediment quality guidelines at allnon-reference sites within t...
which, a full assessment of the recovery of the Northern Wood Preservers site will be made todetermine whether further wor...
REFERENCESAwad, E. 2009. Technical Memorandum: Northern Wood Preservers, 2007 Sample Summary. Sentfrom Wolfgang Scheider t...
Jaagumagi, R., D. Bedard and S. Petro, 1996. Sediment and Biological Assessment of the NorthernWood Preservers Inc. Site, ...
                                 Figures 
21a)                                                                 b)     Figure 1. Location of (a) sampling sites and (...
22                                                                                   Benzo(b)fluoranthene                 ...
23                    3.5*106                                                      *                    3.4*106           ...
24                            a)                      NOR6                                                       b)       ...
25                              a)                                        NOR 6                                           ...
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Northern Wood, Post-Remediation Bio-Monitoring - 2009

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2009 nwp final_report

  1. 1. Post-remediation monitoring of the Northern Wood Preservers Inc. Site in Thunder BayHarbour: Results from the 2009 Biomonitoring Investigation Prepared for: Northern Region Ministry of the Environment Prepared by: Saloni Clerk, Emily Awad, Michelle Palmer, and Steve Petro Biomonitoring Section Environmental Monitoring and Reporting Branch April 2012
  2. 2. EXECUTIVE SUMMARYIn 2009, the Environmental Monitoring and Reporting Branch (EMRB) of the Ministry of theEnvironment (MOE) undertook a biomonitoring investigation of Thunder Bay Harbour in thevicinity of the Northern Wood Preservers Inc. (NWP) site. The survey included the collection ofwater, sediment and benthos samples as well as caged mussel deployments. Sedimenttoxicity bioassays and an assessment of the benthic community structure were alsoconducted.The Thunder Bay Harbour was identified as an Area of Concern in 1985 due, in part, tosediment contamination from polycyclic aromatic hydrocarbons (PAHs; in the form ofcreosote), chlorophenols, and dioxins and furans (impurities in pentachlorophenol) that wereused or produced during wood treatment processes for over 60 years at the NWP site.Following an assessment study in 1995, site-specific clean up criteria were developed andincorporated into the sediment remediation plan (Northern Wood Preservers AlternativeRemediation Concept, NOWPARC). The goal of NOWPARC was to isolate the contaminantsources, clean-up contaminated sediment and enhance fish habitat. The remediation, whichbegan in 1997 and was completed in 2005, included construction of a rockfill containmentperimeter berm to enclose the area of highest sediment contamination, followed by dredging orcapping of sediments within the berm. In addition, clay barriers and a steel sheet pile wall(Waterloo Barrier) were constructed around the site. To monitor the natural recovery ofsediments outside of the berm, regular monitoring of sediments, water, and biota has beenconducted since 1999. The final survey for this site is planned for 2014, after which, a fullassessment of the recovery of the NWP site will be made to determine whether further work(monitoring and/or remediation) is recommended.In the 2009 survey, PAHs were found at very low levels (below detection to trace) in all watersamples collected from the harbour. At NOR5, in the northeast corner of the site, creosote-associated PAHs were elevated above federal guidelines, but were still at trace levels. PAHconcentrations in caged mussels were mainly elevated in sites in the northeast corner as wellas at NOR4, along the eastern side of the berm. Elevated PAHs at some of these sites likelyreflect elevated concentrations in the sediment. PAH compounds associated with creosotewere dominant in the mussels from the sites with elevated sediment concentrations.PAH concentrations in sediment continue to be elevated above provincial guidelines at all non-reference sites within the harbour. Concentrations were highest at NOR6, which exceeded theSevere Effect Level (SEL), followed by NOR4. PAHs have decreased considerably insediment from NOR6 and NOR8, mainly due to decreases in creosote-associated PAHs,which are more susceptible to weathering due to their lower ring number.In the toxicity bioassays, sediment from NOR6 caused 100% mortality of all test invertebrates(amphipods, midges, and mayflies) as well as significant mortality in Fathead Minnows.Sediment from NOR4 caused similar mortality levels in amphipods and chironomids. Despitethese bioassay results, PAHs do not appear to be affecting the resident benthic fauna. Similarto previous studies, benthic communities at both the non-reference and reference sites weredominated by midges, aquatic worms, and fingernail and pea clams. Species richness hasimproved since 2004 at NOR2, NOR8, NOR9, and NOR10, and richness at most non-reference sites was similar to richness at the reference sites. Laboratory bioassays reflect ii
  3. 3. maximum exposure, especially in this case as invertebrates in the harbour can likely avoid thedistinct lenses of contaminated sediment; benthic invertebrate community structure may be abetter measure of the overall conditions in the harbour.At most monitoring sites near the NWP site, there has been a marked improvement insediment concentrations of total PAHs since 2004. Concentrations remain high (>SEL) atNOR6, where physical signs of the creosote contamination are most obvious, as well as atNOR4. Since the 2004 survey, PAHs have increased in sediment at NOR4 as well as NOR3,mainly due to increases in lower ring PAHs, likely a result of weathering of sediments at sitesin the northeast corner and mobilization of these compounds. As creosote contaminatedsediment continues to break down, similar changes in the contamination patterns may beobserved. Total PAHs have increased in caged mussels deployed at some sites in thenortheast corner as well as NOR4. These increases may be due to weathering of sediment-bound PAHs, which could potentially be increasing the bioavailability of PAHs to the cagedmussels.It is recommended that during the next monitoring survey (2014), additional sites be sampledin the northeast corner and near NOR4, to provide for enhanced spatial coverage. In addition,replicate water and sediment samples should be collected to conduct a more robustassessment of the site. Dioxin compounds were initially identified as contaminants of concerndue to elevated levels found in the 1999 survey. Pentachlorophenol was also detected in 1999at low levels. As the remediation was expected to improve sediment concentrations of thesecompounds in addition to PAHs, it is recommended that these compounds be analyzed insediment from the 2014 survey. iii
  4. 4. ACKNOWLEDGMENTSField collection of samples was conducted by Chris Mahon, Steve Petro and Emily Awad.Thank you to Jennifer Winter, Rachael Fletcher, Pat Inch, Michelle McChristie, Tara George,and Trudy Watson-Leung from MOE and Danielle Milani, Matt Graham, Erin Hartman andRoger Santiago from Environment Canada who reviewed earlier versions of this report.Thanks also go to Kinnar Bhatt, Melanie Kipfer and Justin Wilson for preparation and editing offigures. iv
  5. 5. Table of ContentsExecutive Summary.................................................................................................................... iiAcknowledgments ..................................................................................................................... ivBackground ............................................................................................................................... 1Study Design ............................................................................................................................. 2Collection Methods and Laboratory Analyses............................................................................ 2 Water ..................................................................................................................................... 2 Sediments .............................................................................................................................. 2 Sediment Toxicity Bioassays ................................................................................................. 3 Benthic Community Assessment ........................................................................................... 3 Mussels.................................................................................................................................. 3Data Analysis............................................................................................................................. 4 Water ..................................................................................................................................... 4 Sediments .............................................................................................................................. 4 Mussels.................................................................................................................................. 5 Benthic Community Analyses ................................................................................................ 6 Ordinations............................................................................................................................. 6Results and Discussion ............................................................................................................. 7 Observations.......................................................................................................................... 7 Water Chemistry .................................................................................................................... 7 PAHs .................................................................................................................................. 7 Metals, Nutrients, and General Water Chemistry ............................................................... 7 Sediment Chemistry............................................................................................................... 8 PAHs .................................................................................................................................. 8 PCA of PAHs in Sediments ................................................................................................ 9 Metals................................................................................................................................. 9 Total Organic Carbon (TOC), Nutrient, and Particle Size ................................................. 10 Mussels................................................................................................................................ 10 Sediment Toxicity Bioassays ............................................................................................... 11 Benthic Invertebrate Community Structure .......................................................................... 13 Assemblage Composition and Benthic Metrics ................................................................ 13 Benthic Ordinations .......................................................................................................... 15Summary and Conclusions...................................................................................................... 15References .............................................................................................................................. 18 v
  6. 6. FiguresFigure 1. Location of 2009 (a) sampling sites and (b) reference sites in 21Thunder Bay Harbour, near the NWP site.Figure 2. Concentrations of selected PAH compounds above detection 22limits over time in water samples from Thunder Bay Harbour, near theNWP site.Figure 3. Total PAH measured in sediments from Thunder Bay Harbour, 23near the NWP site.Figure 4. Concentrations of creosote associated PAH compounds over 24time in sediments from (a) NOR6 and (b) NOR8 from Thunder BayHarbour, near the NWP site.Figure 5. Concentrations of individual PAH compounds over time in 25sediments from (a) NOR6 and (b) NOR8 from Thunder Bay Harbour, nearthe NWP site.Figure 6. Concentrations of (a) total PAH at NOR3 and NOR4 and 26individual PAH compounds at (b) NOR4 and (c) NOR3 in sediments fromThunder Bay Harbour, near the NWP site.Figure 7. Ratio of ≤ four ring PAH compounds to ≥ five ring PAH 26compounds measured in sediments from the Thunder Bay Harbour, nearthe NWP site.Figure 8. PCA showing patterns in PAH compounds measured in 2009 27sediments among sites from the Thunder Bay Harbour, near the NWP site.Figure 9. Concentrations of metals measured in sediments sampled in the 282009 from the Thunder Bay Harbour, near the NWP site that were abovePSQGs.Figure 10. Iron concentrations in sediment collected outside of the berm 29from Thunder Bay Harbour, near the NWP site, 1995 to 2009.Figure 11. Particle size of sediments sampled in 2009 from the Thunder 30Bay Harbour, near the NWP site.Figure 12. Total PAH concentration in caged mussels deployed in the 31Thunder Bay Harbour, near the NWP site since 2003.Figure 13. Average concentrations of individual PAH compounds in caged 32mussels deployed in the Thunder Bay Harbour, near the NWP site.Figure 14a. Median relative abundance of dominant families (based on 33medians) found in benthic assemblages from sites sampled in 2009 fromthe Thunder Bay Harbour, near the NWP site.Figure 14b. Median relative abundance data of selected families in benthic 33assemblages from sites sampled in the 2009 from the Thunder BayHarbour, near the NWP site. vi
  7. 7. Figure 15. Median abundance (a) and richness (b) of benthic assemblages 34from sites sampled in 2009 from the Thunder Bay Harbour, near the NWPsite.Figure 16. Median diversity indices (DI) of benthic assemblages from sites 35sampled in 2009 from the Thunder Bay Harbour, near the NWP site.Figure 17. PCA showing relative benthic abundances amongst sites 36sampled in 2009 from the Thunder Bay Harbour, near the NWP site.TablesTable 1. PAH compounds measured in water samples collected from 38Thunder Bay Harbour, near the NWP site.Table 2. Metals measured in water samples collected from Thunder Bay 39Harbour, near the NWP site.Table 3. Water chemistry of samples collected from Thunder Bay Harbour, 41near the NWP site.Table 4. Total organic carbon and PAH compounds measured in 42sediments from Thunder Bay Harbour, near the NWP site.Table 5. Total organic carbon, nutrients, metals, and particle size 44measured in sediments from Thunder Bay Harbour, near the NWP site.Table 6. Percent lipids and PAH compounds measured in caged mussels 46deployed in Thunder Bay Harbour, near the NWP site.Table 7. Summary of taxa found in benthic assemblages sampled in 50Thunder Bay Harbour, near the NWP site.Table 8. Summary of benthic metrics for sites sampled in Thunder Bay 52Harbour, near the NWP site.AppendicesI. Map showing 3 zones targeted for remediation 54II. Photographs of 2009 sediment sample from NOR6 55III. Benthic invertebrate community structure, raw data 56IV. Summary of Laboratory Toxicity and Bioaccumulation Test Results 65 vii
  8. 8. BACKGROUNDIn 2009, the Environmental Monitoring and Reporting Branch (EMRB) of the Ministry of theEnvironment (MOE) undertook a biomonitoring investigation of Thunder Bay Harbour in thevicinity of the Northern Wood Preservers Inc. (NWP) site. This work was done at the requestof the Northern Region MOE office as part of the long-term monitoring commitmentsdeveloped for the site.EMRB has been involved in monitoring this site since the mid 1990s and has conductedseveral biomonitoring surveys to date (1995 (Jaagumagi et al., 1996); 1999 (Jaagumagi et al.,2001); 2003/2004 (Baker et al., 2006); as well as a smaller study in 2007 (Awad, 2009)). Thefirst comprehensive survey was conducted in cooperation with Environment Canada in 1995(Jaagumagi et al., 1996) following identification of the Thunder Bay Harbour as an Area ofConcern by the International Joint Commission in 1985. This designation was due, in part, tosediment contamination from polycyclic aromatic hydrocarbons (PAHs; in the form ofcreosote), chlorophenols, and dioxins and furans (impurities in pentachlorophenol). Thesechemicals were used or produced during wood treatment processes for over 60 years at theNWP site.Site-specific clean up criteria were developed following the 1995 assessment study(Jaagumagi et al., 1996; Santiago et al., 2003) which found biological effects (i.e. chronic oracute toxicity) related to PAHs in three areas within about 100 m of shore (Appendix I); theseareas were targeted for clean up in 1996. Other contaminants such as dioxins and furans andpentachlorophenol followed a similar distribution pattern to total PAH, with highest levelsclosest to shore, thus, clean up of sediments for PAHs also addressed these contaminants.This assessment led to the development of the sediment remediation plan, Northern WoodPreservers Alternative Remediation Concept (NOWPARC), a partnership between governmentagencies, industry and the public with three main goals: to isolate the contaminant sources,clean-up contaminated sediment and enhance fish habitat (Santiago et al., 2003).A large amount of sediment (3,200 m3) containing over 150 µg/g total PAHs was removed fromthe footprint area prior to construction of a rockfill containment perimeter berm in 1997. Theberm was constructed to enclose the area of highest sediment contamination (Appendix I); thepool of creosote and the most highly contaminated sediments were subsequently dredged.The remaining sediments within the bermed area were covered with clean fill to form a dry cap.The berm was later redesigned to create embayments and zones of differing depth to providefish habitat (Santiago et al., 2003). A small area in the northeast corner (Appendix I), whereapproximately 80% of the sediments had relatively lower PAH levels (<50 µg/g), was leftoutside of the berm to recover naturally, as it was considered to be a low hazard to aquatic life(Jaagumagi et al., 2001). An assessment of long-term environmental impacts conducted priorto remediation also concluded that due to the presence of creosote-degrading bacteria in thesediment, natural degradation should be sufficient to remediate this area within a reasonabletime frame (one to two decades) (Beak, 1996). To monitor the natural recovery of sedimentsin this area, long-term monitoring was planned for sediments, water, and biota (mussels).In addition to sediment remediation, other measures to prevent movement of contaminantsfrom the site into the harbour were implemented. These measures included construction ofcontaminant isolation structures (i.e. clay barriers) around the pier (original NWP site) andinstallation of the Waterloo Barrier (steel sheet pile wall) to compensate for possible 1
  9. 9. permeability of the clay barrier (Santiago et al., 2003). Remediation of the site began in 1997and the habitat features were completed in 2005.The 2009 survey marks the fourth comprehensive biomonitoring study undertaken by EMRB(1995, 1999, 2004, and 2009). The 1995 survey documented pre-remediation conditions whilethe 1999 survey documented post-remediation conditions. Sampling locations differedbetween the 1999 and 2004 studies, due in part, to the movement or destruction of referencemarkers during construction. Site locations were moved closer to the berm in 2004 to capturepotential sources. Another study is planned for 2014 to complete the ministry’s monitoringcommitment. Subsequently, all monitoring results will be reviewed to determine whetherfurther work is recommended. The following report outlines results from sediment and watersampling, caged mussel deployments, sediment toxicity bioassays, and an assessment of thebenthic community near the NWP site. A comparison of data from 2009 to previous years(since 2004) is included to assess the success of the remediation efforts.STUDY DESIGNWater, sediment and benthos samples were collected on October 5th to 6th, 2009 from thesame 13 sites which have been sampled since 2004. Eleven sites were located in closeproximity to the berm, while two reference sites (NORREF1, NORREF2) were located furtheroffshore near the Thunder Bay Harbour breakwall (Figure 1). Sites closest to the berm wereapproximately 100 m apart. Additional samples were collected at the three transects near thenortheast corner of the berm (NOR5, NOR7, and NOR9), approximately 100 m from thenearshore sites, (Figure 1a). Additional sampling in this corner was undertaken to monitornatural recovery of sediments, which were left in place as per the remedial strategy developedfor the site. One site (NOR11) was located in the wetland area in the northwest corner, whichhas undergone fish habitat enhancements.COLLECTION METHODS AND LABORATORY ANALYSESWaterA single water sample was collected one metre above the sediment at each site using aKemmerer sampler (2.2 L capacity). Temperature and dissolved oxygen were measured in thesurface water at each site using a field meter (YSI 600QS, sonde: YSI 650). Two 500 mL poly-ethylene terephthalate (PET) jars and a 1 L amber bottle were filled at each site. One PET jarfrom each site was preserved with nitric acid to a pH of 2 for metals analysis. Water sampleswere analyzed at the MOE’s Laboratory Services Branch (LaSB) for PAHs (glass amber bottle;LaSB method PAH3424), metals including arsenic and selenium (LaSB methods MET3474and ASSE3089), nutrients (LaSB method TOTNUT3367), solids (LaSB method TSD3188),cations (LaSB method CAT3171), pH, alkalinity and conductivity (LaSB methodPHALCO3218).SedimentsOne sediment sample was collected from each site using a ponar sampler capable ofcollecting the top 10 to 15 cm of sediments. At each site, three sediment grabs were collectedand the surface sediments (~top 5 cm) were homogenized and transferred to sediment bottlesfor submission to LaSB for analyses of PAH (LaSB method PAH3425), total organic carbon 2
  10. 10. (LaSB method ORGC3012), particle size (LaSB method PART3328), nutrients (LaSB methodTNP3116), and metals (LaSB method MET3470).Sediment Toxicity BioassaysThe remaining sediment from NOR3, NOR4, NOR5, NOR6, NOR8, NOR10 and NORREF2was retained for laboratory toxicity bioassays on organisms representing different trophiclevels in order to measure differences in sediment quality. The test sites were chosen basedon the results of previous studies, which indicated impairment in laboratory bioassays and/orbioaccumulation in mussels or laboratory-reared fish. Samples were supplemented withadditional sediment grabs to meet minimum submission requirements (10 L sediment/site).Samples were stored in plastic lined toxicity buckets and transported to the MOE laboratory fortoxicity testing at LaSB’s Aquatic Toxicology Unit. Toxicity was evaluated in the laboratory byexamining survival and growth in Hyalella azteca (amphipod), Chironomus dilutus (midge) andHexagenia spp. (mayfly) exposed to test sediment for 14, 10 and 21 days, respectively.Additionally, sediment bioaccumulation was assessed using juvenile Fathead Minnowsexposed to test sediment for 21 days (Watson-Leung & Simmie, 2011).    Sediments from theDetroit River (Peche Island) and NORREF2 were used as a laboratory control and a fieldreference, respectively, to compare with the biological responses of organisms in the testsediments. The bioassay for sediment from NOR6 was conducted separately in a fumehoodwaterbath due to its strong odour. Sediment samples were thoroughly homogenized prior touse in toxicity tests and sub-samples were submitted for chemical and physicalcharacterization.  Pooled whole non-depurated Fathead Minnows were submitted for chemicalanalysis upon test termination.Benthic Community AssessmentThree petite ponars were taken at each site for benthic community analyses. Sediment fromeach grab was individually sieved through a 500 µm mesh and the benthic invertebratesrecovered were transferred to opaque plastic bottles. The organisms were initially preservedwith formalin (10% formaldehyde) and later transferred to 70% ethanol as it is a betterpreservative for long-term storage (Environment Canada, 2010). Benthic invertebrates weresorted, identified, and enumerated by a consultant taxonomist following Environment Canada’sCanadian Aquatic Biomonitoring Network (CABIN) protocol (Environment Canada, 2010).When possible, all organisms in a sample were identified. However, subsampling was usedwhen samples contained a prohibitively high number of organisms. Subsampling consisted ofplacing the entire sample in a Marchant box (35 x 35 x10 cm; Marchant 1989) divided into 100equal cells, diluting the sample with water, and shaking the box to evenly distribute theorganisms. Cells were then randomly selected and every organism within that cell wasenumerated and identified until a minimum of 300 organisms were completed. Theabundances of the identified species were then extrapolated to the full 100 cells.MusselsMussels (Elliptio complanata) with a shell length between 65 and 72 mm were collected fromBalsam Lake, near Lindsay, Ontario, to be used as biomonitors. Mussels from this locationhave been used by MOE for numerous biomonitoring studies as they have low contaminantlevels (Richman, 2003) and readily accumulate trace metals and organic contaminants 3
  11. 11. (Beckvar et al., 2000; Kauss & Hamdy, 1985). The mussels were stored in aerated roomtemperature Balsam Lake water in 22 L buckets lined with food-grade plastic inserts. Thesamples were transported to the MOE laboratory where they were filled with pure oxygen andshipped to Thunder Bay. The following day the bags were opened and aerated untildeployment. The mussels were then transferred into envelope-shaped cages (30 x 45cm)made of galvanized mesh poultry netting (1.25cm). Single cages, containing six mussels,were deployed at the 13 study sites and submerged 1 m above the sediment for 20 to 21 daysfrom September 15th to October 5th to 6th, 2009. Upon retrieval, the condition of the musselswas determined; open shell and strong odour were used as an indication of a dead anddecomposing mussel. The soft tissue of the living mussels were immediately removed(shucked) using a knife that was rinsed with hexane before and between each mussel. Thesoft tissue was drained, wrapped individually in foil, placed in a separate plastic bag for eachstation, and stored in dry ice. Samples were shipped overnight to LaSB, and subsequentlyfrozen.  Three mussels from each site were analyzed for PAHs (LaSB method PAH3351) andlipids (LaSB method LIPID3136).DATA ANALYSISWaterWater chemistry results were compared to reference sites and to Provincial Water QualityObjectives (PWQO; MOE, 1994). PWQOs are protective of all forms of aquatic life through alllife stages during indefinite exposure to the water.Results for aluminum should be interpreted with caution as samples in the current study wereunfiltered and the PWQO is based on filtered samples. Although LaSB measures totalchromium, the PWQOs are for chromium III and chromium VI. The PWQO for chromium VIwas used as it is the most toxic form and is the principle form found in surface waters (CCME,1999). For all metals, LaSB reported concentrations have an associated uncertainty value (i.e.concentrations reported +/- the uncertainty value). Concentrations that exceeded the PWQOwhen the uncertainty value was added were reported as exceeding the PWQO.Concentrations that were ≤0 when the uncertainty value was subtracted were reported as non-detects (ND).PAH concentrations were compared to federal guidelines (CCME, 1999) as advised by MOEsStandards Development Branch. The safety factors used in the federal guidelines provide amore realistic interpretation of potential concerns to aquatic life compared to the PWQOs (TimFletcher, MOE, personal communication, 2010).Water quality was also compared over time for those parameters that exceeded PWQOs (i.e.PAH compounds). Although the analytical method for PAHs in water changed between2003/2004 and 2009, there were no changes in detection limits for individual compounds.Detection limits for metals were lower in 2009 (MET3474) as compared to earlier studies(MET3386).SedimentsSediment chemistry results were compared to the Provincial Sediment Quality Guidelines(PSQG) Lowest Effect Level (LEL) and Severe Effect Level (SEL) (Persaud et al., 1993). The 4
  12. 12. LEL is the level of contamination that can be tolerated by the majority of sediment-dwellingorganisms, while the SEL is the level of contamination that is expected to be detrimental to themajority of sediment-dwelling organisms. The PSQG for total PAH is based on the sum of the16 compounds identified as priority pollutants by the Environmental Protection Agency. Totaland individual PAH SELs depend on site-specific total organic carbon (TOC). The SEL ismultiplied by the site-specific TOC value (to a maximum of 10%), and the PAH concentration isthen compared to this corrected SEL value, on a site-by-site basis. Total PAHs from the 2009survey were calculated two ways: as the sum of the 16 priority pollutants (total PAH(16)) and asthe sum of all PAH compounds measured by the MOE analytical method (total PAH(18)).PAH concentrations from 2009 were compared to 2007 and 2004 concentrations (Awad, 2009;Baker et al., 2006). The PAH analytical method was improved in 2009, resulting in moreaccurate and precise estimates and decreases in method detection limits of 5 to 54 timeshistorical detection limits (Eric Reiner, Ministry of the Environment, personal communication,2011). The 2009 method identified and quantified PAH compounds at 2 to 20 ng/g whereasthe historical method detected compounds at 20 to 40 ng/g (Boden et al., 2010; Bodnar, 2004).In addition, two new parameters were quantified, benzo(e)pyrene and perylene, and wereincluded in the total PAH(18).Comparisons of iron levels in sediment collected outside of the berm (data pooled across sites)between 1995 and 2009 were summarized with boxplots displaying the median or 50thpercentile (middle line of the box), 25th percentile (bottom of the box), 75th percentile (top of thebox), maximum (top whisker) and minimum (bottom whisker) of the data, as well as outliers(●). Since the data was not normally distributed, the non-parametric Kruskal-Wallis test wasused to determine statistically significant differences between years. A post hoc multiplecomparison test (Dunn’s test due to unequal sample sizes) was used to distinguish betweenyears (SigmaStat, 2004).Quantal results (i.e. survival) from the sediment toxicity bioassays were compared to thereference site using Fisher’s exact test (SYSTAT, 2004) (Watson-Leung & Simmie, 2011).Quantitative results (i.e. growth) could not be assessed statistically due to the lack of fieldreplicates; however, general comparisons to the reference site were made (Watson-Leung &Simmie, 2011). Biota sediment accumulation factors (BSAFs) in Fathead Minnow werecalculated for PAHs where sediment and tissue concentrations were above trace levels.BSAFs are the ratio of the concentration in biota to the concentration in the sediment, andprovide a measure of the bioavailability of sediment associated organic contaminants ormetals. Organic contaminants, such as PAHs, accumulate in the lipid fraction of the tissue andthe organic carbon fraction of the sediment and therefore, concentrations were corrected forlipid and organic carbon.MusselsTotal PAH levels in mussels were compared among sites in the 2009 survey and among yearsat each site. For results below method detection limits, total PAH was calculated using half thedetection limit. Mussel concentrations were not lipid corrected as the relationship betweenlipid content and total PAH concentration was not significant. Total PAHs were comparedamong sites in the 2009 study and among years at each site. Mussels were deployed inSeptember in all years; in 2003, they were also deployed in August and these data wereincluded in the comparison. Comparisons were summarized with boxplots of the data for each 5
  13. 13. site and year combination. There are no provincial or federal PAH guidelines against whichmussel concentrations can be compared.   Since the data were not normally distributed, thenon-parametric Kruskal-Wallis test and a post hoc test (Tukey or Dunn’s test) were used todistinguish between sites or years (SigmaStat, 2004). Statistical results should be interpretedwith caution as they are based on a maximum of 3 replicates.Benthic Community AnalysesBenthic invertebrates were identified to the lowest taxonomic level possible, generally speciesor genus. The benthic community at each site was then characterized using the followingtraditional summary metrics: (i) richness, which was calculated as the number of speciescollected (ii) total abundance of benthic invertebrates, (iii) number of EPT, which wascalculated as the total number of Ephemeroptera, Plecoptera and Trichoptera speciescollected, (iv) % composition of dominant/indicator taxa, (v) community diversity, which wascalculated using Simpson’s Diversity Index and Shannon’s Diversity Index, (vii) communityevenness, which was calculated using Pielou’s Index, and (viii) tolerance, which wascalculated using Hilsenhoff’s Biotic Index Summary metrics were calculated for each of thethree replicates per site; medians are reported here. Reported values are per sample area ofthe petite ponar, which was 2310 cm2 (volume of 2.4 L).Benthic community summary metrics were compared among sites and between the 2004 and2009 sampling period. One-way Analysis of Variance (ANOVA) and Kruskal-Wallis testsfollowed by post hoc Tukey tests were used as appropriate based on normality and equalvariance tests (SigmaStat, 2004). Statistical results should be interpreted with caution asresults are based on only 3 replicates.OrdinationsSpatial patterns in sediment PAH concentrations and benthic communities were examinedusing principal components analysis (PCA). PCA is based on a linear response model andwas selected as the most appropriate ordination technique based on detrendedcorrespondence analysis maximum gradient lengths of <4 (Lepš and Šmilauer, 2003). TwoPCAs were performed, the first examined spatial patterns in the relative concentrations ofindividual PAH compounds while the second examined spatial patterns in the relativeabundances of benthic families. Prior to running the benthic community PCA, replicatesamples were averaged and rare taxa (families accounting for ≤ 2% of total abundance) wereremoved.PCA results were summarized in ordination diagrams with sites displayed as points and PAHcompounds and benthic families displayed as arrows. Sites with similar PAH or benthiccommunities plotted close together. The importance of certain variables to individual sites canbe assessed by examining the relative position of sites to the arrows; for example, sites whichplot closer to the tip of the arrow of a given PAH compound tended to have a higher relativeconcentration of that compound as compared to sites farther away from the arrow.The significance of sediment parameters (PAHs, metals, ions, nutrients, total organic carbon,and sediment particle size) in explaining differences in benthic communities among sites wasassessed using redundancy analysis (RDA), a linear multivariate ordination technique.Colinearity amongst the sediment parameters was reduced using forward selection and 6
  14. 14. parameters significant at p≤0.05, as determined by Monte Carlo permutation tests, wereretained in the RDA (Lepš and Šmilauer, 2003).All ordinations were run using CANOCO version 4.5 (Ter Braak, 2002).RESULTS AND DISCUSSIONObservationsDuring sample collection, physical signs of creosote contamination were observed, forexample, oil on the water surface or dark oil patches in the sediment. At NOR6, oil waspresent at the surface and oil-filled bubbles emerged during water sampling. During sedimentcollection, there was a very strong petroleum-based odour at this site, and large patches of oil(in veins or layers) were observed within the sediment (Appendix II). Oil on the water surfaceas well as petroleum-based odour were also noted to a lesser extent at NOR3, NOR4 andNOR8, and smaller patches of oil were present within the sediment samples at these sites. AtNOR2 and NOR10, oil was also observed in the sediments, but at much lower levels.Water ChemistryPAHsPAH compounds were below detection at both reference sites and the four southernmost sites(NOR1, NOR2, NOR3, and NOR4) but were detected in trace amounts at five of the six sitesnortheast of the berm (NOR5, NOR7, NOR8, NOR9, NOR10) as well as at NOR11 (Table 1).All PAHs were below detection at NOR6, which is surprising due to the pungent odour andvisible oil on the water surface. A total of four compounds were detected in the water samples;fluoranthene and phenanthrene were present at most sites, pyrene was present at NOR5,NOR7 and NOR10, and chrysene was present at NOR5. PAH concentrations were highest atNOR5. Phenanthrene, fluoranthene and pyrene increased between 2004 and 2009 at NOR5(Figure 2) and the latter two exceeded the CCME guidelines in 2009 (Table 1).Trace amounts of PAH compounds were similarly detected in previous studies but generally athigher concentrations. Most PAH compounds were highest at NOR2 in 2007 but by 2009 allcompounds were below detection at this site (Figure 2, Table 1). Total PAH at NORREF2decreased from trace amounts in August 2003 to below detection in 2009. Total PAHconcentrations have decreased over time with concentrations in samples from 2000 (averageof samples taken from September to October from sites outside of the berm) ranging from 191to 465 ng/L (Jaagumagi et al., 2001) compared to 12 to 141 ng/L in 2009.Metals, Nutrients, and General Water ChemistryFive metals exceeded their PWQOs: zinc, cadmium, aluminum, iron and chromium (Table 2).Zinc and cadmium were elevated at NORREF2, although cadmium only exceeded the PWQOwhen the uncertainty value was added. These metals were not elevated at the nearshoresites, suggesting levels were impacted by offshore conditions in the harbour.Aluminum exceeded the PWQO at six non-reference sites and was highest at NOR7 andNOR8, in the northeast corner of the berm. As the aluminum results are based on unfiltered 7
  15. 15. samples, the values reflect both particulate and dissolved aluminum concentrations, and arelikely biased high.Iron also exceeded the PWQO at NOR7 and NOR8 while chromium was at the PWQO atNOR8 only when the uncertainty value was added (Table 2). In contrast to previous studies,zinc exceeded the PWQO at NORREF2 in 2009. Conversely, cobalt and cadmium havedecreased at most sites and no longer exceed their PWQOs (Table 2).General water chemistry was largely similar among sites (Table 3). Dissolved oxygen wasgenerally around 10 mg/L at the sites, with the exception of NOR6 (9.4 mg/L) and NOR9 (7.9mg/L); all sites were above the 6 mg/L minimum that the PWQO requires. Total phosphoruswas slightly above the PWQO at NOR5 but was below it at all other sites (Table 3).Sediment ChemistryPAHsOverall, concentrations of PAH compounds exceeded the LEL 45% of the time (118/260possible exceedances) and the SEL 4% of the time (11/260). PAHs exceeded PSQGs at allsites except NORREF1 (Table 4). Total PAH(16) levels in 2009 were highest at NOR6 (845,300ng/g) and were above the SEL. Levels were much lower at the other sites, ranging from 2035ng/g at NORREF1 to 194,040 ng/g at NOR4; however, levels still exceeded the LEL (4000ng/g) with the exception of NORREF1 (Table 4, Figure 3).Compared to sediment concentrations in 2004, PAH levels decreased by 76% at NOR6 and97% at NOR8 (Figure 3). Total PAH(16) decreased by 96% between 2004 and 2007 at NOR8,falling below the SEL and remaining low in 2009 (a 12% decrease). At NOR6, total PAHdecreased by 63% between 2004 and 2007 and 34% between 2007 and 2009; however totalPAH remained above the SEL in 2009.Reductions in total PAH at NOR6 and NOR8 were largely due to decreases in PAHcompounds associated with creosote, such as phenanthrene, pyrene, and fluoranthene (Figure4). These PAHs were dominant in all sediment samples collected since 2004 (Figure 5) andcollectively accounted for 49 to 59% of total PAH at NOR6 and 32 to 58% of total PAH atNOR8 from 2004 to 2009. The decrease in these creosote associated PAHs may be due totheir lower benzene ring number (≤ three) as these compounds are more susceptible toweathering than higher ring number PAHs (Murphy and Brown, 2005). Prior to the remediation,natural biodegradation was predicted for this area (Beak, 1996).With the decrease in total PAH levels at NOR6 and NOR8, fewer individual PAH compoundsexceeded their SELs over time (Figure 5). For example, nine PAH compounds, including thecreosote-associated compounds, exceeded their SELs at NOR8 in 2004 while all PAHcompounds were below their respective SELs in 2007 and 2009 (Figure 5b). At NOR6 therehas been a consistent decrease in the number of individual PAH compounds above the SELfrom 12 compounds in 2004, to 10 compounds in 2007, to eight compounds in 2009 (Figure5a). These results suggest that PAH-associated impacts to the benthic community may havedecreased over time at these sites.Between 2004 and 2009, PAH levels increased at NOR3 and NOR4 (Figures 3 and 6a).Although most PAH compounds increased at these sites, increases in total PAH were largely 8
  16. 16. due to those compounds with ≤ three benzene rings (i.e. phenanthrene, pyrene, andfluoranthene, which are dominant in creosote; Figure 6b & c). The higher levels of lower ringnumber PAH compounds may be related to mobilization away from areas whereconcentrations were historically elevated (i.e. NOR6 and NOR8). The increase in the ratio of ≤three ring compounds to ≥ four ring compounds between 2004 and 2009 at NOR3 and NOR4supports this interpretation (Figure 7). Past studies have suggested that concentrations oflighter, and hence more mobile, PAH compounds may increase away from source regions overtime (Murphy and Brown, 2005). Sediment concentrations of PAHs can vary, however, ascreosote was found to occur as distinct globules or lenses in the sediment (Jaagumagi et al.,2001).PCA of PAHs in SedimentsPCA explained 88.2% of the variation in PAH levels amongst the sites (Figure 8). Sites withthe highest levels of total PAHs are on the right-hand side of the ordination diagram. Thesesites (NOR6, NOR4, NOR3) are characterized by relatively high levels of ≤ three ring numberPAHs, many of which are dominant in creosote. Sites plotted on the left-hand side of theordination diagram are characterized by higher relative levels of four to five ring number PAHcompounds. The close positioning of most sites on the left-hand side of the diagram toNORREF1 and NORREF2 indicates similar PAH signatures at these sites. Only NOR11appears to have a different PAH profile compared to the other sites as it had relatively highlevels of benzo(a)anthracene (BaA); this PAH accounted for 6.5% of total PAH at NOR11compared to 3.8 to 4.9% of total PAH at other sites.MetalsIn total, eight out of 28 trace metals/metalloids exceeded PSQGs (Table 5, Figure 9). Ofthese, only iron exceeded the SEL (40,000 µg/g). Iron was elevated above the SEL at mostsites, with the exception of the reference sites, NOR9 and NOR11. Previous studies have alsoshown iron elevated above the SEL (Baker et al., 2006; Awad, 2009) likely due to regionalgeology (Cannon et al., 2007). Iron levels appear to have increased somewhat since theremediation; levels in samples collected outside of the berm were significantly higher in 2009than in 1995 (p<0.05; Figure 10). This increase may be a result of dredging activities thatdisturbed sediments containing naturally high iron or the locally quarried shale from the GreatWest Timber Pit (Gunflint) used to construct the berm may be a source of iron to the harbour(McIlveen, 1998).In 2007, Environment Canada detected arsenic above the SEL near the southeast corner ofthe NWP site (Awad, 2009). In response, EMRB began monitoring arsenic in 2009 and foundthat all sites were below the SEL. However, the highest arsenic concentration (23 µg/g) wasmeasured at NOR3 which is located just north of where Environment Canada reported highlevels (Table 5, Figure 9). The elevated arsenic near the NWP site is likely related to thehistorical use of chromated copper arsenate in wood treatment (Jaagumagi et al., 1996).Most metals that exceeded the LEL at non-reference sites also exceeded the LEL at thereference sites. Arsenic and manganese, however, were only elevated at non-reference sites,with the exception of NOR9 or NOR11 (Table 5, Figure 9). Metal levels were generally lowerat NOR11 compared to the other sites. 9
  17. 17. Similar levels of most metals between reference and non-reference sites have been reportedsince the mid-1990s (Jaagumagi et al., 1996; Jaagumagi et al., 2001; Baker et al., 2006;Awad, 2009). This finding suggests that background metal concentrations are elevated and,with the exception of iron, arsenic, and manganese, high metal levels in sediments do notappear to be related to operations at the Northern Wood Preservers site.Total Organic Carbon (TOC), Nutrient, and Particle SizeTOC exceeded the LEL (1%) but not the SEL (10%) at all sites, ranging from 1.1% at NOR11to 3.6% at NOR8 (Table 5). Total Kjeldahl nitrogen and total phosphorus exceeded the LEL,but not the SEL, at all sites except NOR11, where only total Kjeldahl nitrogen was elevated,and NORREF1, where only total phosphorus was elevated (Table 5).Particle size was generally similar among sites, consisting of 65 to 73% silt with the remainderconsisting of clay (≤ 24%) and sand (≤ 15%) (Figure 11). Unlike the other sites, particle size atNOR11 was 66% sand, 28% silt and 6% clay. When metals were normalized to particle size,the concentrations at NOR11 were comparable to the other sites. This suggests that the lowlevels of metals were due to the greater proportion of sand at NOR11 as metals preferentiallysorb and concentrate in sediment with a finer grain than sand (Forstner and Wittman, 1983).MusselsMussel mortalities of a single replicate occurred at NOR7, NOR8, and NOR9. Total PAH(16) inmussels was elevated at four of the 13 sites (Table 6, Figure 12). Most of these sites were inthe northeast corner (i.e. NOR7, NOR8, NOR10; median range: 927 to 4454 ng/g; Table 6,Figure 12). NOR4 was the only site outside of this area where high levels were detected(median total PAH: 1058 ng/g). PAHs may be more bioavailable in these areas due to higherlevels in sediments nearby. For example, sediment PAH was highest at NOR6 and NOR4(Figure 3). Levels in mussels from NOR6 were low, even though the sediment concentrationswere highest. The obvious contamination at this site (i.e. pungent odour, oil present on watersurface and in bubbles below the surface) may have led to valve closure (Meador, 2003),reducing filter-feeding and potentially limiting PAH uptake. However, mussel weight at NOR6did not differ from that at other sites after the deployment (p>0.05), and no mortalities wereobserved at NOR6, suggesting the three week exposure may have been too short to result inan impact. Lack of uptake in mussels may also be due to water concentrations being belowdetection limits at NOR6. However, mussel uptake was observed at NOR4, where sedimentconcentrations were elevated and water concentration were also below detection limits.Statistical differences among sites were not detected (p>0.05), possibly due to the smallsample sizes.The detection of higher levels in the northeast corner is not unexpected, as this area is outsideof the berm and was left for natural recovery because PAH levels were relatively low andconsidered to be a low hazard to aquatic life (Jaagumagi et al., 2001).PAH levels in 2009 at some of the sites in the northeast corner (NOR9 and NOR10) weresignificantly (p<0.05) higher than at least one of the historic mussel deployments (NOR9:2009>2004; NOR10: 2009>2003 (August) & 2004; Figure 12). Although concentrations were 10
  18. 18. elevated in 2009 at NOR4 and NOR8 and the Kruskal-Wallis test showed a significantdifference among years (p<0.05), the difference was not great enough to be detected with thepost-hoc multiple comparison test. Similarly, although total PAH at NOR7 increasedconsiderably in 2009, the difference was not statistically significant (post-hoc multiplecomparison test, p>0.05). The lack of significance may be due to the small sample sizes andhigh variation between mussels within a site. Large variability among replicates has beenpreviously found in this organism during caged exposures (Kauss & Hamdy, 1991). At NOR6,total PAH was significantly lower in 2004 (p<0.05) compared to all other years (2003, 2007 and2009); concentrations in 2009 were not significantly different than in 2003 or 2007.Total PAH in mussels deployed at the other sites were relatively low and similar to pastdeployments; concentrations ranged from median levels below method detection (NOR2 andNOR5) to 517 ng/g at NOR11. Although total PAH at NOR11 increased significantly in 2007(p<0.05) from 2004 levels, concentrations in 2009 decreased down to levels observed in 2003and 2004. Total PAH was below detection in all three mussels from each of the referencesites, suggesting that PAH detections in the non-reference sites are related to historicoperations at the NWP site.Elevated levels of total PAHs in mussels deployed in 2009 at NOR4 and in the northeastcorner were due to the same individual PAHs which were dominant in sediments:phenanthrene, pyrene, and fluoranthene (Figure 13). These three PAHs, which are indicativeof creosote, accounted for 59 to 75% of total PAH at these sites. The natural weathering ofsediment since the remediation may be increasing the bioavailability of PAHs to mussels, andresulting in elevated levels at sites in the northeast corner.The variation in mussel uptake of PAHs between 2004 and 2009 makes it difficult to assesstemporal trends. Contaminant trends in mussels will be reassessed after the 2014 survey.Sediment Toxicity BioassaysA brief summary of the results of the toxicity bioassays is included here; see Appendix IV forthe complete summary (Watson-Leung & Simmie, 2011). Test validity, integrity of the testsystem, organism health, and technician proficiency were confirmed for all four organismsbased on survival and growth in laboratory control sediments (Detroit River, Peche Island) andreference toxicant testing (potassium chloride).In the Hyalella azteca sediment toxicity test, mean survival was significantly lower than thereference site at NOR6 (0%) and NOR4 (40±28%) (p<0.001). Mean survival was ≥94% at allother sites. There were no apparent impacts on growth at any sites compared to the referencesite. In the Chironomus dilutus sediment toxicity test, significant impacts on mean survivalwere observed at NOR6 (0%) and NOR4 (24%) (p<0.001). Mean survival was ≥74% at allother sites. Growth of C. dilutus from NOR4 was 54% of reference growth, and was ≥81% ofreference growth at all other stations. In the Hexagenia sediment toxicity test, mean survivalwas significantly lower than the reference site at NOR6 only (0%) (p<0.001). Mean survivalwas ≥86% at all other sites. Hexagenia did not grow as well in the reference site as thelaboratory control, despite similar grain size and higher TOC in the reference sediment. Mayflygrowth was lower at NOR3, NOR4, and NOR8 compared to the reference site. For all threetests, statistical significance of growth effects could not be assessed due to the lack of fieldreplicates (Environment Canada, 2005).  11
  19. 19. In the Fathead Minnow bioaccumulation test, mean survival was significantly lower than thereference site at NOR6 (40±34%). Although statistical analysis showed a significant differencebetween mean survival at NOR4 (88±13%) and the reference (100%), the high survival rateindicates there was no biological impact. Surviving minnows from each treatment weresubmitted for analysis of PAHs, lipids and, with the exception of NOR6 (due to insufficienttissue), metals; BSAFs were calculated for PAHs only (Appendix IV, Table 5c). Uptake ofPAHs occurred at NOR3, NOR6 and NOR8, but the BSAFs at all sites were low (≤0.02). ABSAF value less than one indicates that the contaminant has a greater affinity for sedimentover the organism, signifying that the contaminant is less bioavailable to the organism. ABSAF greater than one indicates that the contaminant has a greater affinity for the organismand that bioaccumulation has taken place.PAH concentrations in exposed Fathead Minnows were highest at NOR6 and NOR8, and as inpast bioassays, phenanthrene, pyrene and fluoranthene, which are associated with creosotecontamination, were the major contributors. In some cases, PAHs in exposed fish from the2009 sediment bioassays were lower than in the previous bioassay (2004), especially at NOR6where lipid–corrected tissue concentrations of total PAHs decreased by 67%. At NOR4 andNOR8, tissue concentrations were higher in 2009. At NOR3 and NOR10, exposed FatheadMinnows accumulated PAH compounds that were not observed in tissue from the 2004bioassay.Metal concentrations were highest in the overlying water from the reference station in all testsexcept for Hexagenia. Metals were also elevated in the overlying water from the laboratorycontrol in the Hyalella and the Fathead Minnow tests. The reason for this is unknown;however, it suggests that metals did not cause the observed toxicity. Arsenic was elevatedabove the PWQO at NOR6 for the Fathead Minnow test only. In previous bioassays, metallevels in overlying water did not correlate well with sediment concentrations or observedtoxicity (Trudy Watson-Leung, MOE, personal communication, 2011). PAHs were generallyhighest in the overlying water from NOR4 and/or NOR6, where significant impacts on survivalof the exposed organisms was observed, indicating that PAH levels were the likely cause oftoxicity. PAHs were also higher in the overlying water from NOR4 and NOR6 as compared tothe 2004 bioassay.Many metals exceeded the LEL in the sediment used in the toxicity bioassays, and in manycases, levels were highest at the reference station (NORREF2), as was observed with theoverlying water. Arsenic was elevated above the SEL at NOR3 and iron was elevated abovethe SEL at NOR3 and NOR5; no toxicity was observed at these sites. PAHs at all sites wereelevated above concentrations in the reference sediment, although some individual PAHs andtotal PAH exceeded the LEL in the reference sediment. PAHs were highest in sediment fromNOR6 and NOR4, where impacts on survival and/or growth were observed. As analyticalresults for the field sediment showed, total PAHs declined between 2004 and 2009 in thelaboratory sediment at NOR6 and NOR8 and increased at NOR3 and NOR4. Althoughconcentrations have declined at NOR6, they were considerably higher than at NOR4 whichwas elevated compared to NOR8 and NOR3 (NOR6>>NOR4>>NOR8>NOR3), correspondingto the patterns of toxicity.Laboratory bioassays reflect maximum exposure due to the mixing of sediment prior to testing.For example, comparisons of sediment concentrations of PAHs between the field sedimentand the laboratory sediment showed increases (13 to 67%) in the laboratory sediment from 12
  20. 20. NOR4 and NOR6. At NOR8, which showed reduced survival in the 2004 toxicity bioassays,there were much greater increases in PAHs in the laboratory sediment (63 to 90%); however,the levels were still much lower than at NOR4 (1.3 to 4.0 fold) and NOR6 (3.7 to 12.5 fold). Inaddition, the sediment samples for the toxicity bioassays were collected to a depth of 10 to 15cm in order to fulfill test volume requirements, whereas most benthic invertebrates typicallyinhabit the top 5 cm of sediment (Jaagumagi and Persaud, 1993). Elevated levels due tothese factors likely result in an increase in the bioavailability of some contaminants that maynot be influencing organisms in the Thunder Bay Harbour. This is especially important at thissite, as the patchy nature of PAHs in the sediment has been previously established(Jaagumagi et al., 2001).As observed in the 2004 toxicity bioassay, organisms exposed to NOR6 sediment were themost significantly impaired. Reduced survival was also observed in H. azteca and C. dilutusexposed to NOR4 sediment in 2009, while survival was reduced for C. dilutus and FatheadMinnow at NOR8 in 2004. This shift in impairment from NOR8 (2004) to NOR4 (2009) is likelycaused by the decrease in sediment concentrations at NOR8 and the increase in sedimentconcentrations at NOR4 between 2004 and 2009.The results of the 2009 sediment toxicity bioassays clearly indicate impaired survival fororganisms exposed to NOR6 sediment, as well as NOR4 sediment, in some cases.Benthic Invertebrate Community StructureAssemblage Composition and Benthic MetricsIn total, 114 species were identified across the 13 sites (Appendix III). Species belonged to 28families and 15 orders. Most species belonged to three families: Chironomidae (midges; 38species), Naididae (aquatic worms; 32 species), or Sphaeriidae (fingernail and pea clams;eight species); each of the remaining 25 families was represented by < 4 species (Table 7).Benthic communities were dominated by Chironomidae, Naididae, and Sphaeriidae; thesefamilies were nearly ubiquitous and collectively accounted for 71 to 98% of total benthicabundance (Table 8, Figure 14a). These families also dominated benthic communities inprevious studies (Jaagumagi et al., 2001; Baker et al., 2006).Other families were present at fewer sites. Valvatidae (valve snails) were present at all but twosites (NOR3, NOR11) while the remaining families were present at four to eight sites.Asellidae (freshwater crustaceans) and Hydrobiidae (mud snails) were generally only presentat the reference sites and sites on the north side of the berm (i.e. NOR9, NOR10 and NOR11).Of the orders most sensitive to pollution (Ephemeroptera, Plecoptera and Trichoptera), onlyTrichoptera was present. Baker et al. (2006) similarly found that Ephemeroptera andPlecoptera were not present at the study sites in 2004. Trichoptera was present at NOR2,NOR5, NOR8, NOR9, NOR10, NOR11 and the reference sites, although its relativeabundance was low (≤ 2%) (Table 8, Figure 14b). The number of EPT species at eachindividual site did not differ between 2004 and 2009 (p-values>0.05).The median abundance of benthic animals at the non-reference sites averaged 316 ± 170individuals while the median abundance at the reference sites averaged 335 ± 139 individuals.Although abundance at the non-reference sites did not significantly differ from the reference 13
  21. 21. sites (p>0.05), median abundance at NOR7 (71 individuals) was significantly less thanabundance at NOR10 (757.5 individuals) (p<0.05; Table 8, Figure 15a). High benthicabundance at NOR10 may be related to its relatively shallow depth and aquatic vegetationalong the north side of the berm. The 1999 study also found that more abundant and diversecommunities near the berm were associated with the presence of aquatic vegetation near theberm (Jaagumagi et al., 2001). Higher total benthic abundance may be related to increasedhabitat types and food sources related to aquatic vegetation. Total benthic abundancegenerally did not significantly differ between 2004 and 2009 except at NOR1 where abundancedecreased and NOR5 where abundance increased (p-values<0.05).Median richness at the non-reference and reference sites averaged 24 ± 7 species and 29 ± 1species, respectively. Although median richness ranged from 13 species at NOR6 to 33species at NOR2 (Table 8, Figure 15b), differences between individual sites were notsignificant (p-values>0.05). Between 2004 and 2009, richness significantly increased atNOR2, NOR8, NOR9 and NOR10 (p-values<0.02). Median richness at these sites increasedby 10 to 18 species and richness in 2009 ranged from 29 to 33 species, similar to medianrichness at the reference sites. Increases in median richness were largely due to increases inthe number of species of oligochaete worms and chironomids. Similarly, median diversity(Shannon DI and Simpson DI) did not significantly differ between individual sites (p-values>0.05). However, diversity was relatively low at NORREF2 and two sites near the dock(NOR6 and NOR11; Table 8, Figure 16a&b). Shannon DI increased over time at NOR9(p<0.03).Median evenness at the non-reference and reference sites averaged 0.79 ± 0.06 and 0.70 ±0.16, respectively. A community with the exact same number of individuals per species wouldhave an evenness value of 1. Evenness differed among sites (p=0.01; Table 8, Figure 16c)with evenness at NOR7 significantly greater than at NORREF2 (p<0.05). Evenness atNORREF2, as well as at NOR8, decreased between 2004 and 2009 (p-values<0.03).Decreased evenness at NORREF2 was due to increasing dominance by oligochaete worms.In general, water quality, as inferred from the Hillsenhoff Index, was better (HBI < 6.86) at sitesnorth of NOR4 (except NOR11) compared to the southern sites (HBI > 7.20) (Figure 16d).Inferred water quality was also better at NORREF1 as compared to NORREF2. However,differences in HBI were only significant for NOR1 (median HBI of 7.68) and NORREF1(median HBI of 6.46) (p<0.05).Similar to previous studies, benthic communities at both the non-reference and reference siteswere dominated by midges, aquatic worms, and fingernail and pea clams. These organismsare tolerant of organic pollutants and are common in areas with nutrient enrichment, poorwater quality and soft lake sediments (Hynes, 1960; Jaagumagi et al., 2001; Baker et al.,2006). Also similar to previous studies, benthic community metrics generally did notsignificantly differ among sites, nor did they differ between the non-reference and referencesites. For example, NOR4 and NOR6, the only two sites with PAH compounds above site-specific SELs, generally had intermediate levels of the community metrics (with the exceptionof low median richness at NOR6). These findings suggest background conditions in theharbour have a greater impact on the benthic communities than site-specific pollutant levels.However, as reported results are based on a small number of replicates per site (three), thelack of statistical significance should be interpreted with caution. 14
  22. 22. Benthic OrdinationsPCA on the relative abundances of the eight common benthic families explained 96% of thevariation in benthic communities in 2009 (Figure 17).Sites were primarily separated based on the relative abundances of aquatic worms (familyNaididae) and midges (Family Chironomidae). Sites to the right side of the ordination hadhigher relative abundances of aquatic worms, whereas sites to the left side of the ordinationhad higher relative abundances of chironomids (Figure 17). Sites were also separated basedon relative abundance of fingernail and pea clams (family Sphaeriidae) with sites to the top ofthe ordination having higher relative abundances (Figure 17).The benthic communities of the reference sites differed greatly with NORREF1 dominated bymidges (40% of total benthic abundance) and NORREF2 dominated by aquatic worms (79% oftotal benthic abundance). NORREF1 also had much higher abundances of valve snails andfingernail and pea clams.Based on the relative positioning of sites, benthic communities in 2009 do not appear to bedistinguished based on PAH levels. For example, NOR6, which had the highest sedimentlevels of total PAH, plotted closest to NORREF1, which had the lowest total PAH concentration(Figure 17). Not surprisingly, the RDA found that PAH compounds did not explain a significantamount of the among-site variation in benthic communities, further suggesting the communitiesare not significantly impacted by site-specific pollutant levels. Previous studies (Jaagumagi etal., 2001; Baker et al., 2006) also found that differences among benthic communities could notbe attributed to the presence of PAH compounds. The lack of response of the benthiccommunity to PAH contamination may be the result of active organism avoidance as most ofthe PAH is present as discrete blobs or drops of oil (Jaagumagi et al, 2001). Additionalsediment parameters examined in this survey (metals, ions, nutrients, total organic carbon,and sediment particle size) did not significantly distinguish between the sites (as determined byRDA).SUMMARY AND CONCLUSIONSPAHs were at low levels (below detection to trace) in all water samples collected from theharbour. At NOR5, fluoranthene and pyrene, two compounds associated with creosote, wereelevated above CCME guidelines, but were still at trace levels. PAH concentrations in cagedmussels were mainly elevated in sites in the northeast corner (NOR7, NOR8, NOR10) as wellas at NOR4. Elevated PAHs at some of these sites likely reflect elevated concentration in thesediment. Levels in mussels from NOR6 were low, even though the sediment concentrationswere highest at this site. PAH levels in mussels were significantly higher in 2009 than in 2004at NOR9 and NOR10. Although a significant difference was not detected between years atNOR4, NOR7, and NOR8, concentrations have increased considerably. PAH compoundsassociated with creosote (phenanthrene, pyrene, and fluoranthene) were dominant in themussels from the sites with elevated sediment concentrations. Due to the variation in musseluptake of PAHs between 2004 and 2009, contaminant trends will be reassessed after the 2014survey. 15
  23. 23. PAH concentrations continue to be elevated above provincial sediment quality guidelines at allnon-reference sites within the harbour. Concentrations were highest at NOR6, whichexceeded the SEL, followed by NOR4. PAHs have decreased considerably in sediment fromNOR6 and NOR8, mainly due to decreases in those compounds indicative of creosotecontamination (phenanthrene, pyrene, and fluoranthene), which are more susceptible toweathering due to their lower ring number.Sediment from NOR6 (highest total PAH concentration), caused 100% mortality of all testinvertebrates (Hyalella amphipods, Chironomus midges, and Hexagenia mayflies) as well assignificant mortality in the Fathead Minnows. Sediment from NOR4 (second highest total PAHconcentration), caused similar mortality levels to amphipods and chironomids. Similarly, in2004, NOR6 sediments caused the most mortality. Exposure to NOR8 sediment did not causethe impairments which were observed in 2004, likely due to decreases in sedimentconcentrations at this site. Increases in sediment concentrations at NOR4, especially of thosecompounds associated with creosote, may have resulted in the observed toxicity in 2009.Despite elevated PAH concentrations in all non-reference sediments, especially NOR6, andthe reduced survival of benthic organisms exposed to some of those sediments during toxicitybioassays (NOR4 and NOR6), PAHs do not appear to be affecting the resident benthic fauna.Similar to previous studies, benthic communities at both the non-reference and reference siteswere dominated by midges, aquatic worms, and fingernail and pea clams. Species richnesshas improved since 2004 at NOR2, NOR8, NOR9, and NOR10, and richness at most non-reference sites was similar to richness at the reference sites.The detection of higher PAH levels in sediment and biota from sites in the northeast cornerwas expected as this area is outside of the zone of remediation and was left for naturalrecovery due to relatively low concentrations. Elevated PAHs as well as reduced survival oflaboratory organisms at NOR4 may be due to the mobilization of lower ring PAHs in creosotefrom the northeast corner. As creosote contaminated sediment continues to break down,similar changes in the contamination patterns may be observed. Laboratory bioassays reflectmaximum exposure, especially in this case as invertebrates in the harbour can likely avoid thedistinct lenses of contaminated sediment, so benthic invertebrate community structure may bea better measure of the conditions in the harbour. Comparison of benthic invertebratecommunity structure to reference stations suggests that background conditions in the harbourhave a greater impact on the benthic communities than site-specific pollutant levels.At most monitoring sites near the Northern Wood Preserver site, there has been a markedimprovement in sediment concentrations of total PAHs since 2004. Concentrations remainhigh (>SEL) at NOR6, where physical signs of the creosote contamination are most obvious,as well as at NOR4. Since the 2004 survey, PAHs have increased in sediment at NOR4 aswell as NOR3, mainly due to increases in lower ring PAHs, likely a result of weathering ofsediments at sites in the northeast corner and mobilization of these compounds. Total PAHshave increased in caged mussels deployed at some sites in the northeast corner as well asNOR4. These increases may be due to weathering of sediment-bound PAHs, which couldpotentially be increasing the bioavailability of PAHs to the caged mussels.The long-term monitoring plan, developed as part of the NOWPARC strategy, was intended toassess the area outside the berm for impacts on aquatic life and to monitor natural recovery ofthe sediment. As part of this monitoring plan, the final survey will be conducted in 2014, after 16
  24. 24. which, a full assessment of the recovery of the Northern Wood Preservers site will be made todetermine whether further work (monitoring and/or remediation) is recommended.It is recommended that additional sites be sampled in the northeast corner and near NOR4during the next monitoring survey (2014) to provide for enhanced spatial coverage. If possible,replicate samples should be collected to enhance statistical analysis of differences (andsimilarities) among sites. Dioxin compounds were initially identified as contaminants of concerndue to elevated levels found in the 1999 survey (Jaagumagi et al., 1996). Pentachlorophenolwas also detected but concentrations were generally at low levels (80 ng/g; Jaagumagi et al.,1996). Remediation actions were expected to also improve sediment concentrations of thesecompounds as they were elevated in the same areas as PAHs. It is recommended that thesecompounds be analyzed in sediment from the 2014 survey to determine if remediation wassuccessful in decreasing the concentrations. 17
  25. 25. REFERENCESAwad, E. 2009. Technical Memorandum: Northern Wood Preservers, 2007 Sample Summary. Sentfrom Wolfgang Scheider to John Taylor. Ministry of the Environment.Baker, S., R. Fletcher, and S.Petro. 2006. Northern Wood Preservers Alternative RemediationConcept (NOWPARC) Bioassessment of Northern Wood Preservers Site Thunder Bay Harbour, LakeSuperior 2003 and 2004.Beak, 1996. Preliminary assessment of long-term impacts associated with a NOWPARC remediation ofthe Northern Wood Preservers sediments. Beak Consultants Limited, Brampton, ON. Ref: 20425.1;Draft for discussion.Beckvar, N., S. Salazar, M. Salazar, K. Finkelstein. 2000. An in situ assessment of mercurycontamination in the Sudbury River, Massachusetts, using transplanted freshwater mussels (Elliptiocomplanata). Can. J. Fish. Aquat. Sci. 57: 1103-1112.Boden, A., D. Morse, and M. Cepeda. 2011. The determination of polycyclic aromatic hydrocarbons(PAHs) in soil and sediment by isotope-dilution gas chromatography- mass spectrometry (GCMS);method PSAPAH-E3425. Laboratory Services Branch, Quality Management Section, Ministry of theEnvironment.Bodnar, J. 2004. The determination of polynuclear aromatic hydrocarbons (PAH) in soil and sedimentsby gas chromatography-mass spectrometry (GC-MS); method PSAPAH-E3350. Laboratory ServicesBranch, Quality Management Section, Ministry of the Environment.Canadian Council of Ministers of the Environment (CCME). 1999. Canadian water quality guidelinesfor the protection of aquatic life: Chromium – Hexavalent chromium and trivalent chromium. In:Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment,Winnipeg.Cannon, W.F., G.L. LaBerge, J.S. Klasner, and K.J. Schulz, 2007. The Gogebic iron range—a sampleof the northern margin of the Penokean fold and thrust belt: U.S. Geological Survey Professional Paper1730, 44 p.Environment Canada. 2005. Guidance Document on Statistical Methods for Environmental ToxicityTests. EPS 1/RM/46. Ottawa, Ontario. 170 p.Environment Canada. 2010. Laboratory Methods: Processing, taxonomy, and quality control ofbenthic macroinvertebrate samples. Retrieved December 1, 2010, from Environment Canada Website: http://www.ec.gc.ca/Publications/default.asp?lang=En&xml=CDC2A655-A527-41F0-9E61-824BD4288B98.Forstner, U. and G.T.W. Wittmann. 1983. Metal Pollution in the Aquatic Environment. Springer-Verlag,New York, 486 pp.Hynes, H.B.N., 1960. The Biology of Polluted Waters. Liverpool University Press, Liverpool. 202pp.Jaagumagi, R. and D. Persaud. 1993. Sediment Assessment: A guide to Study Design, Sampling andLaboratory Analysis. Ministry of the Environment. 18
  26. 26. Jaagumagi, R., D. Bedard and S. Petro, 1996. Sediment and Biological Assessment of the NorthernWood Preservers Inc. Site, Thunder Bay. July 1995 and September 1995. Ministry of theEnvironment.Jaagumagi, R., D. Bedard and R. Santiago, 2001. Northern Wood Inc. (NOWPARC) Post-ConstructionBaseline Study 1999. Ministry of the Environment and Environment Canada.Kauss, P.B., and Y.S. Hamdy. 1985. Biological monitoring of organochlorine contaminants in the St.Clair and Detroit Rivers using introduced clams, Elliptio complanatus. J. Great Lakes Res. 11(3): 247-263.Lepš, J. and P. Šmilauer. 2003. Multivariate Analysis of Ecological Data using CANOCO. CambridgeUniversity Press, Cambridge, UK.Marchant, R. 1989. A subsampler for samples of benthic macroinvertebrates. Bulletin of the AustralianSociety for Limnology. 12: 49-52.McIlveen, W.D., 1998. Investigation into chemical composition of shales in Ontario, 1997. Report No.SDB-023-3511-1998. September 1998.Meador, J. P., 2003. Bioaccumulation of PAHs in Marine Invertebrates, in PAHs: An EcotoxicologicalPerspective (ed. P.E.T. Douben), John Wiley & Sons, Ltd, Chichester, UK.MOE, 1994. Water Management Policies, Guidelines, Provincial Water Quality Objectives of theMinistry of the Environment and Energy. Ministry of Environment and Energy, Toronto, Ontario.Murphy, B.L. and J. Brown. 2005. Environmental Forensics Aspects of PAHs from Wood Treatmentwith Creosote Compounds. Environmental Forensics 6: 151-159.Persaud, D., R. Jaagumagi, and A. Hayton. 1993. Guidelines for the Protection and Management ofAquatic Sediment Quality in Ontario. Ministry of Environment and Energy, Toronto, Ontario.Richman, L.A. 2003. Niagara River Mussel Biomonitoring Program 2000. Water Monitoring Section,Environmental Monitoring and Reporting Branch, Ontario Ministry of Environment.Santiago, R., P. Inch, R. Jaagumagi, and J-P. Pelletier. 2003. Northern Wood Preservers SedimentRemediation Case Study. Presentation to the 2nd International Symposium on ContaminatedSediments. Retrieved June 6, 2011, from: http://www.scs2003.ggl.ulaval.ca/Histories/Santiago2.pdf.SigmaStat, 2004. SigmaStat for Windows version 3.11, Systat Software, Inc.SYSTAT Statistics, Inc. 2004. SYSTAT® 11 Statistics I. Richmond, CA.Watson-Leung, T. and L. Simmie. 2011. Northern Wood Preservers, NOWPARC (Thunder Bay,Ontario) Summary of Laboratory Toxicity and Bioaccumulation Test Results. Aquatic ToxicologySection, Ministry of the Environment. August 2011.Ter Braak, C.J.F. and P. Smilauer. 2002. CANOCO Reference manual and CanoDraw for WindowsUser’s guide: Software for Canonical Community Ordination (version 4.5). Microcomputer Power(Ithaca, NY, USA), 500pp. 19
  27. 27.                  Figures 
  28. 28. 21a) b) Figure 1. Location of (a) sampling sites and (b) reference sites in Thunder Bay Harbour, near the NWP site. Transects located in the northeast corner of the berm are circled in red.
  29. 29. 22 Benzo(b)fluoranthene Benzo(e)pyrene 60 Fluoranthene 50 PAH (ng/L) Phenanthrene 40 Pyrene 30 20 10 0 0 7 _ 0 4 _ 0 9 _ 0 9 _ 0 9 _ 0 9 _ 0 4 _ 0 9 _ 0 4 _ 0 9 _03 2_ 5 5 7 8 9 2 R R R R R R R10 R10 R11 R11 EF O O O O O O O O O O RR N N N N N N N N N N O NFigure 2. Concentrations of select PAH compounds above detection limits over time in water samples fromThunder Bay Harbour, near the NWP site. The two numbers following each site name indicate the year ofsample collection. Levels of pyrene and fluoranthene exceeded the CCME guidelines (25 ng/L for pyreneand 40 ng/L for fluoranthene) at NOR5 in 2009.
  30. 30. 23 3.5*106 * 3.4*106 3.3*106 2004 3.2*106 2007 2009 1.3*106 * 1.2*106 1.1*106 1.0*106 Total PAH (ng/g) 9.0*105 * * 8.0*105 7.0*105 6.0*105 5.0*105 4.0*105 3.0*105 2.0*105 1.0*105 0.0 1 2 3 4 5 6 7 8 9 10 11 1 2 O R O R O R O R O R O R O R O R O R R R EF EF N N N N N N N N N O O R R N N R R O O N NFigure 3. Total PAH(16) measured in sediments from Thunder Bay Harbour, near the NWP site. Total PAHabove the site-specific SEL are marked with a red asterisk.
  31. 31. 24 a) NOR6 b) NOR8 Fluoranthene 2.0*105 Fluoranthene 8.0*105 Phenanthrene Phenanthrene Pyrene PyrenePAH Concentration ng/g PAH Concentration ng/g 1.5*105 6.0*105 4.0*105 1.0*105 2.0*105 5.0*104 0.0 0.0 2004 2007 2009 2004 2007 2009 Year Year Figure 4. Concentrations of creosote associated PAH compounds over time in sediments from (a) NOR6 and (b) NOR8 from Thunder Bay Harbour, near the NWP site. Note the difference in scale (y-axis) between (a) and (b).
  32. 32. 25 a) NOR 6 b) NOR 8 2009 2009 200000 8 PAHs >SEL(*) * 4000 0 PAHs >SEL (*) 100000 * * 2000 * * * * *PAH concentration (ng/g) PAH concentration (ng/g) 0 0 2007 2007 10 PAHs >SEL (*) * * 4000 0 PAHs >SEL (*) 200000 * 2000 100000 * * 0 2004 * * * * * 0 2004 800000 12 PAHs >SEL (*) * 200000 9 PAHs >SEL (*) * * * 400000 * 100000 * * * * * * * 0 * * * * 0 * * l l Ac e Ac A P F P F 0 A AN B a Ba B b Bg B k C D FL F0 ID 0 P0 PY e Ac A P F P AN B a B a B b B g B k F 0 A FL F0 ID 0 P0 PY N Ac C D N Figure 5. Concentrations of individual PAH compounds over time in sediments from (a) NOR6 and (b) NOR8 from Thunder Bay Harbour, near the NWP site. Levels of phenanthrene (PO), pyrene (PY) and fluoranthene (FL) are highlighted in yellow. Codes for other individual PAH compounds are provided in Table 4. PAHs above the site-specific SEL are marked with a red asterisk.

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