Northern Wood, Post-Remediation Bio-Monitoring - 2009

1. Post-remediation monitoring of the Northern
Wood Preservers Inc. Site in Thunder Bay
Harbour: 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. EXECUTIVE SUMMARY
In 2009, the Environmental Monitoring and Reporting Branch (EMRB) of the Ministry of the
Environment (MOE) undertook a biomonitoring investigation of Thunder Bay Harbour in the
vicinity of the Northern Wood Preservers Inc. (NWP) site. The survey included the collection of
water, sediment and benthos samples as well as caged mussel deployments. Sediment
toxicity bioassays and an assessment of the benthic community structure were also
conducted.
The Thunder Bay Harbour was identified as an Area of Concern in 1985 due, in part, to
sediment contamination from polycyclic aromatic hydrocarbons (PAHs; in the form of
creosote), chlorophenols, and dioxins and furans (impurities in pentachlorophenol) that were
used 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 and
incorporated into the sediment remediation plan (Northern Wood Preservers Alternative
Remediation Concept, NOWPARC). The goal of NOWPARC was to isolate the contaminant
sources, clean-up contaminated sediment and enhance fish habitat. The remediation, which
began in 1997 and was completed in 2005, included construction of a rockfill containment
perimeter berm to enclose the area of highest sediment contamination, followed by dredging or
capping 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 of
sediments outside of the berm, regular monitoring of sediments, water, and biota has been
conducted since 1999. The final survey for this site is planned for 2014, after which, a full
assessment 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 water
samples 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. PAH
concentrations in caged mussels were mainly elevated in sites in the northeast corner as well
as at NOR4, along the eastern side of the berm. Elevated PAHs at some of these sites likely
reflect elevated concentrations in the sediment. PAH compounds associated with creosote
were 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 the
Severe Effect Level (SEL), followed by NOR4. PAHs have decreased considerably in
sediment 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. Despite
these bioassay results, PAHs do not appear to be affecting the resident benthic fauna. Similar
to previous studies, benthic communities at both the non-reference and reference sites were
dominated by midges, aquatic worms, and fingernail and pea clams. Species richness has
improved 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
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3. maximum exposure, especially in this case as invertebrates in the harbour can likely avoid the
distinct lenses of contaminated sediment; benthic invertebrate community structure may be a
better measure of the overall conditions in the harbour.
At most monitoring sites near the NWP site, there has been a marked improvement in
sediment concentrations of total PAHs since 2004. Concentrations remain high (>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 as well as NOR3,
mainly due to increases in lower ring PAHs, likely a result of weathering of sediments at sites
in the northeast corner and mobilization of these compounds. As creosote contaminated
sediment continues to break down, similar changes in the contamination patterns may be
observed. Total PAHs have increased in caged mussels deployed at some sites in the
northeast 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 caged
mussels.
It is recommended that during the next monitoring survey (2014), additional sites be sampled
in 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 robust
assessment of the site. Dioxin compounds were initially identified as contaminants of concern
due to elevated levels found in the 1999 survey. Pentachlorophenol was also detected in 1999
at low levels. As the remediation was expected to improve sediment concentrations of these
compounds in addition to PAHs, it is recommended that these compounds be analyzed in
sediment from the 2014 survey.
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4. ACKNOWLEDGMENTS
Field 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 and
Roger 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 of
figures.
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5. Table of Contents
Executive Summary.................................................................................................................... ii
Acknowledgments ..................................................................................................................... iv
Background ............................................................................................................................... 1
Study Design ............................................................................................................................. 2
Collection Methods and Laboratory Analyses............................................................................ 2
Water ..................................................................................................................................... 2
Sediments .............................................................................................................................. 2
Sediment Toxicity Bioassays ................................................................................................. 3
Benthic Community Assessment ........................................................................................... 3
Mussels.................................................................................................................................. 3
Data Analysis............................................................................................................................. 4
Water ..................................................................................................................................... 4
Sediments .............................................................................................................................. 4
Mussels.................................................................................................................................. 5
Benthic Community Analyses ................................................................................................ 6
Ordinations............................................................................................................................. 6
Results 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 .......................................................................................................... 15
Summary and Conclusions...................................................................................................... 15
References .............................................................................................................................. 18
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6. Figures
Figure 1. Location of 2009 (a) sampling sites and (b) reference sites in 21
Thunder Bay Harbour, near the NWP site.
Figure 2. Concentrations of selected PAH compounds above detection 22
limits over time in water samples from Thunder Bay Harbour, near the
NWP site.
Figure 3. Total PAH measured in sediments from Thunder Bay Harbour, 23
near the NWP site.
Figure 4. Concentrations of creosote associated PAH compounds over 24
time in sediments from (a) NOR6 and (b) NOR8 from Thunder Bay
Harbour, near the NWP site.
Figure 5. Concentrations of individual PAH compounds over time in 25
sediments from (a) NOR6 and (b) NOR8 from Thunder Bay Harbour, near
the NWP site.
Figure 6. Concentrations of (a) total PAH at NOR3 and NOR4 and 26
individual PAH compounds at (b) NOR4 and (c) NOR3 in sediments from
Thunder Bay Harbour, near the NWP site.
Figure 7. Ratio of ≤ four ring PAH compounds to ≥ five ring PAH 26
compounds measured in sediments from the Thunder Bay Harbour, near
the NWP site.
Figure 8. PCA showing patterns in PAH compounds measured in 2009 27
sediments among sites from the Thunder Bay Harbour, near the NWP site.
Figure 9. Concentrations of metals measured in sediments sampled in the 28
2009 from the Thunder Bay Harbour, near the NWP site that were above
PSQGs.
Figure 10. Iron concentrations in sediment collected outside of the berm 29
from Thunder Bay Harbour, near the NWP site, 1995 to 2009.
Figure 11. Particle size of sediments sampled in 2009 from the Thunder 30
Bay Harbour, near the NWP site.
Figure 12. Total PAH concentration in caged mussels deployed in the 31
Thunder Bay Harbour, near the NWP site since 2003.
Figure 13. Average concentrations of individual PAH compounds in caged 32
mussels deployed in the Thunder Bay Harbour, near the NWP site.
Figure 14a. Median relative abundance of dominant families (based on 33
medians) found in benthic assemblages from sites sampled in 2009 from
the Thunder Bay Harbour, near the NWP site.
Figure 14b. Median relative abundance data of selected families in benthic 33
assemblages from sites sampled in the 2009 from the Thunder Bay
Harbour, near the NWP site.
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7. Figure 15. Median abundance (a) and richness (b) of benthic assemblages 34
from sites sampled in 2009 from the Thunder Bay Harbour, near the NWP
site.
Figure 16. Median diversity indices (DI) of benthic assemblages from sites 35
sampled in 2009 from the Thunder Bay Harbour, near the NWP site.
Figure 17. PCA showing relative benthic abundances amongst sites 36
sampled in 2009 from the Thunder Bay Harbour, near the NWP site.
Tables
Table 1. PAH compounds measured in water samples collected from 38
Thunder Bay Harbour, near the NWP site.
Table 2. Metals measured in water samples collected from Thunder Bay 39
Harbour, near the NWP site.
Table 3. Water chemistry of samples collected from Thunder Bay Harbour, 41
near the NWP site.
Table 4. Total organic carbon and PAH compounds measured in 42
sediments from Thunder Bay Harbour, near the NWP site.
Table 5. Total organic carbon, nutrients, metals, and particle size 44
measured in sediments from Thunder Bay Harbour, near the NWP site.
Table 6. Percent lipids and PAH compounds measured in caged mussels 46
deployed in Thunder Bay Harbour, near the NWP site.
Table 7. Summary of taxa found in benthic assemblages sampled in 50
Thunder Bay Harbour, near the NWP site.
Table 8. Summary of benthic metrics for sites sampled in Thunder Bay 52
Harbour, near the NWP site.
Appendices
I. Map showing 3 zones targeted for remediation 54
II. Photographs of 2009 sediment sample from NOR6 55
III. Benthic invertebrate community structure, raw data 56
IV. Summary of Laboratory Toxicity and Bioaccumulation Test Results 65
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8. BACKGROUND
In 2009, the Environmental Monitoring and Reporting Branch (EMRB) of the Ministry of the
Environment (MOE) undertook a biomonitoring investigation of Thunder Bay Harbour in the
vicinity of the Northern Wood Preservers Inc. (NWP) site. This work was done at the request
of the Northern Region MOE office as part of the long-term monitoring commitments
developed for the site.
EMRB has been involved in monitoring this site since the mid 1990s and has conducted
several 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)). The
first 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 of
Concern by the International Joint Commission in 1985. This designation was due, in part, to
sediment contamination from polycyclic aromatic hydrocarbons (PAHs; in the form of
creosote), chlorophenols, and dioxins and furans (impurities in pentachlorophenol). These
chemicals were used or produced during wood treatment processes for over 60 years at the
NWP 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 or
acute toxicity) related to PAHs in three areas within about 100 m of shore (Appendix I); these
areas were targeted for clean up in 1996. Other contaminants such as dioxins and furans and
pentachlorophenol followed a similar distribution pattern to total PAH, with highest levels
closest 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 Wood
Preservers Alternative Remediation Concept (NOWPARC), a partnership between government
agencies, 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 from
the footprint area prior to construction of a rockfill containment perimeter berm in 1997. The
berm was constructed to enclose the area of highest sediment contamination (Appendix I); the
pool 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 provide
fish habitat (Santiago et al., 2003). A small area in the northeast corner (Appendix I), where
approximately 80% of the sediments had relatively lower PAH levels (<50 µg/g), was left
outside 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 prior
to remediation also concluded that due to the presence of creosote-degrading bacteria in the
sediment, natural degradation should be sufficient to remediate this area within a reasonable
time frame (one to two decades) (Beak, 1996). To monitor the natural recovery of sediments
in this area, long-term monitoring was planned for sediments, water, and biota (mussels).
In addition to sediment remediation, other measures to prevent movement of contaminants
from the site into the harbour were implemented. These measures included construction of
contaminant isolation structures (i.e. clay barriers) around the pier (original NWP site) and
installation of the Waterloo Barrier (steel sheet pile wall) to compensate for possible
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9. permeability of the clay barrier (Santiago et al., 2003). Remediation of the site began in 1997
and 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 while
the 1999 survey documented post-remediation conditions. Sampling locations differed
between the 1999 and 2004 studies, due in part, to the movement or destruction of reference
markers during construction. Site locations were moved closer to the berm in 2004 to capture
potential sources. Another study is planned for 2014 to complete the ministry’s monitoring
commitment. Subsequently, all monitoring results will be reviewed to determine whether
further work is recommended. The following report outlines results from sediment and water
sampling, caged mussel deployments, sediment toxicity bioassays, and an assessment of the
benthic 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 DESIGN
Water, sediment and benthos samples were collected on October 5th to 6th, 2009 from the
same 13 sites which have been sampled since 2004. Eleven sites were located in close
proximity to the berm, while two reference sites (NORREF1, NORREF2) were located further
offshore near the Thunder Bay Harbour breakwall (Figure 1). Sites closest to the berm were
approximately 100 m apart. Additional samples were collected at the three transects near the
northeast corner of the berm (NOR5, NOR7, and NOR9), approximately 100 m from the
nearshore sites, (Figure 1a). Additional sampling in this corner was undertaken to monitor
natural recovery of sediments, which were left in place as per the remedial strategy developed
for the site. One site (NOR11) was located in the wetland area in the northwest corner, which
has undergone fish habitat enhancements.
COLLECTION METHODS AND LABORATORY ANALYSES
Water
A single water sample was collected one metre above the sediment at each site using a
Kemmerer sampler (2.2 L capacity). Temperature and dissolved oxygen were measured in the
surface 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 jar
from each site was preserved with nitric acid to a pH of 2 for metals analysis. Water samples
were analyzed at the MOE’s Laboratory Services Branch (LaSB) for PAHs (glass amber bottle;
LaSB method PAH3424), metals including arsenic and selenium (LaSB methods MET3474
and ASSE3089), nutrients (LaSB method TOTNUT3367), solids (LaSB method TSD3188),
cations (LaSB method CAT3171), pH, alkalinity and conductivity (LaSB method
PHALCO3218).
Sediments
One sediment sample was collected from each site using a ponar sampler capable of
collecting the top 10 to 15 cm of sediments. At each site, three sediment grabs were collected
and the surface sediments (~top 5 cm) were homogenized and transferred to sediment bottles
for submission to LaSB for analyses of PAH (LaSB method PAH3425), total organic carbon
2

10. (LaSB method ORGC3012), particle size (LaSB method PART3328), nutrients (LaSB method
TNP3116), and metals (LaSB method MET3470).
Sediment Toxicity Bioassays
The remaining sediment from NOR3, NOR4, NOR5, NOR6, NOR8, NOR10 and NORREF2
was retained for laboratory toxicity bioassays on organisms representing different trophic
levels in order to measure differences in sediment quality. The test sites were chosen based
on the results of previous studies, which indicated impairment in laboratory bioassays and/or
bioaccumulation in mussels or laboratory-reared fish. Samples were supplemented with
additional 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 for
toxicity testing at LaSB’s Aquatic Toxicology Unit. Toxicity was evaluated in the laboratory by
examining survival and growth in Hyalella azteca (amphipod), Chironomus dilutus (midge) and
Hexagenia spp. (mayfly) exposed to test sediment for 14, 10 and 21 days, respectively.
Additionally, sediment bioaccumulation was assessed using juvenile Fathead Minnows
exposed to test sediment for 21 days (Watson-Leung & Simmie, 2011). Sediments from the
Detroit River (Peche Island) and NORREF2 were used as a laboratory control and a field
reference, respectively, to compare with the biological responses of organisms in the test
sediments. The bioassay for sediment from NOR6 was conducted separately in a fumehood
waterbath due to its strong odour. Sediment samples were thoroughly homogenized prior to
use in toxicity tests and sub-samples were submitted for chemical and physical
characterization. Pooled whole non-depurated Fathead Minnows were submitted for chemical
analysis upon test termination.
Benthic Community Assessment
Three petite ponars were taken at each site for benthic community analyses. Sediment from
each grab was individually sieved through a 500 µm mesh and the benthic invertebrates
recovered were transferred to opaque plastic bottles. The organisms were initially preserved
with formalin (10% formaldehyde) and later transferred to 70% ethanol as it is a better
preservative for long-term storage (Environment Canada, 2010). Benthic invertebrates were
sorted, identified, and enumerated by a consultant taxonomist following Environment Canada’s
Canadian Aquatic Biomonitoring Network (CABIN) protocol (Environment Canada, 2010).
When possible, all organisms in a sample were identified. However, subsampling was used
when samples contained a prohibitively high number of organisms. Subsampling consisted of
placing the entire sample in a Marchant box (35 x 35 x10 cm; Marchant 1989) divided into 100
equal cells, diluting the sample with water, and shaking the box to evenly distribute the
organisms. Cells were then randomly selected and every organism within that cell was
enumerated and identified until a minimum of 300 organisms were completed. The
abundances of the identified species were then extrapolated to the full 100 cells.
Mussels
Mussels (Elliptio complanata) with a shell length between 65 and 72 mm were collected from
Balsam Lake, near Lindsay, Ontario, to be used as biomonitors. Mussels from this location
have been used by MOE for numerous biomonitoring studies as they have low contaminant
levels (Richman, 2003) and readily accumulate trace metals and organic contaminants
3

11. (Beckvar et al., 2000; Kauss & Hamdy, 1985). The mussels were stored in aerated room
temperature Balsam Lake water in 22 L buckets lined with food-grade plastic inserts. The
samples were transported to the MOE laboratory where they were filled with pure oxygen and
shipped to Thunder Bay. The following day the bags were opened and aerated until
deployment. 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 days
from September 15th to October 5th to 6th, 2009. Upon retrieval, the condition of the mussels
was determined; open shell and strong odour were used as an indication of a dead and
decomposing 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. The
soft tissue was drained, wrapped individually in foil, placed in a separate plastic bag for each
station, and stored in dry ice. Samples were shipped overnight to LaSB, and subsequently
frozen. Three mussels from each site were analyzed for PAHs (LaSB method PAH3351) and
lipids (LaSB method LIPID3136).
DATA ANALYSIS
Water
Water chemistry results were compared to reference sites and to Provincial Water Quality
Objectives (PWQO; MOE, 1994). PWQOs are protective of all forms of aquatic life through all
life stages during indefinite exposure to the water.
Results for aluminum should be interpreted with caution as samples in the current study were
unfiltered and the PWQO is based on filtered samples. Although LaSB measures total
chromium, the PWQOs are for chromium III and chromium VI. The PWQO for chromium VI
was 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 PWQO
when 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 MOEs
Standards Development Branch. The safety factors used in the federal guidelines provide a
more realistic interpretation of potential concerns to aquatic life compared to the PWQOs (Tim
Fletcher, 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 between
2003/2004 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).
Sediments
Sediment 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. LEL is the level of contamination that can be tolerated by the majority of sediment-dwelling
organisms, while the SEL is the level of contamination that is expected to be detrimental to the
majority of sediment-dwelling organisms. The PSQG for total PAH is based on the sum of the
16 compounds identified as priority pollutants by the Environmental Protection Agency. Total
and individual PAH SELs depend on site-specific total organic carbon (TOC). The SEL is
multiplied by the site-specific TOC value (to a maximum of 10%), and the PAH concentration is
then compared to this corrected SEL value, on a site-by-site basis. Total PAHs from the 2009
survey were calculated two ways: as the sum of the 16 priority pollutants (total PAH(16)) and as
the 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 more
accurate and precise estimates and decreases in method detection limits of 5 to 54 times
historical 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 whereas
the 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 were
included 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 50th
percentile (middle line of the box), 25th percentile (bottom of the box), 75th percentile (top of the
box), 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 was
used to determine statistically significant differences between years. A post hoc multiple
comparison test (Dunn’s test due to unequal sample sizes) was used to distinguish between
years (SigmaStat, 2004).
Quantal results (i.e. survival) from the sediment toxicity bioassays were compared to the
reference 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 field
replicates; however, general comparisons to the reference site were made (Watson-Leung &
Simmie, 2011). Biota sediment accumulation factors (BSAFs) in Fathead Minnow were
calculated 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, and
provide a measure of the bioavailability of sediment associated organic contaminants or
metals. Organic contaminants, such as PAHs, accumulate in the lipid fraction of the tissue and
the organic carbon fraction of the sediment and therefore, concentrations were corrected for
lipid and organic carbon.
Mussels
Total PAH levels in mussels were compared among sites in the 2009 survey and among years
at each site. For results below method detection limits, total PAH was calculated using half the
detection limit. Mussel concentrations were not lipid corrected as the relationship between
lipid content and total PAH concentration was not significant. Total PAHs were compared
among sites in the 2009 study and among years at each site. Mussels were deployed in
September in all years; in 2003, they were also deployed in August and these data were
included in the comparison. Comparisons were summarized with boxplots of the data for each
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13. site and year combination. There are no provincial or federal PAH guidelines against which
mussel concentrations can be compared. Since the data were not normally distributed, the
non-parametric Kruskal-Wallis test and a post hoc test (Tukey or Dunn’s test) were used to
distinguish between sites or years (SigmaStat, 2004). Statistical results should be interpreted
with caution as they are based on a maximum of 3 replicates.
Benthic Community Analyses
Benthic invertebrates were identified to the lowest taxonomic level possible, generally species
or genus. The benthic community at each site was then characterized using the following
traditional summary metrics: (i) richness, which was calculated as the number of species
collected (ii) total abundance of benthic invertebrates, (iii) number of EPT, which was
calculated as the total number of Ephemeroptera, Plecoptera and Trichoptera species
collected, (iv) % composition of dominant/indicator taxa, (v) community diversity, which was
calculated using Simpson’s Diversity Index and Shannon’s Diversity Index, (vii) community
evenness, which was calculated using Pielou’s Index, and (viii) tolerance, which was
calculated using Hilsenhoff’s Biotic Index Summary metrics were calculated for each of the
three replicates per site; medians are reported here. Reported values are per sample area of
the petite ponar, which was 2310 cm2 (volume of 2.4 L).
Benthic community summary metrics were compared among sites and between the 2004 and
2009 sampling period. One-way Analysis of Variance (ANOVA) and Kruskal-Wallis tests
followed by post hoc Tukey tests were used as appropriate based on normality and equal
variance tests (SigmaStat, 2004). Statistical results should be interpreted with caution as
results are based on only 3 replicates.
Ordinations
Spatial patterns in sediment PAH concentrations and benthic communities were examined
using principal components analysis (PCA). PCA is based on a linear response model and
was selected as the most appropriate ordination technique based on detrended
correspondence analysis maximum gradient lengths of <4 (Lepš and Šmilauer, 2003). Two
PCAs were performed, the first examined spatial patterns in the relative concentrations of
individual PAH compounds while the second examined spatial patterns in the relative
abundances of benthic families. Prior to running the benthic community PCA, replicate
samples were averaged and rare taxa (families accounting for ≤ 2% of total abundance) were
removed.
PCA results were summarized in ordination diagrams with sites displayed as points and PAH
compounds and benthic families displayed as arrows. Sites with similar PAH or benthic
communities plotted close together. The importance of certain variables to individual sites can
be assessed by examining the relative position of sites to the arrows; for example, sites which
plot closer to the tip of the arrow of a given PAH compound tended to have a higher relative
concentration 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 was
assessed using redundancy analysis (RDA), a linear multivariate ordination technique.
Colinearity amongst the sediment parameters was reduced using forward selection and
6

14. parameters significant at p≤0.05, as determined by Monte Carlo permutation tests, were
retained in the RDA (Lepš and Šmilauer, 2003).
All ordinations were run using CANOCO version 4.5 (Ter Braak, 2002).
RESULTS AND DISCUSSION
Observations
During sample collection, physical signs of creosote contamination were observed, for
example, oil on the water surface or dark oil patches in the sediment. At NOR6, oil was
present at the surface and oil-filled bubbles emerged during water sampling. During sediment
collection, 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 surface
as well as petroleum-based odour were also noted to a lesser extent at NOR3, NOR4 and
NOR8, and smaller patches of oil were present within the sediment samples at these sites. At
NOR2 and NOR10, oil was also observed in the sediments, but at much lower levels.
Water Chemistry
PAHs
PAH 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 sites
northeast 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 and
visible 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 at
NOR5. 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 at
higher concentrations. Most PAH compounds were highest at NOR2 in 2007 but by 2009 all
compounds were below detection at this site (Figure 2, Table 1). Total PAH at NORREF2
decreased from trace amounts in August 2003 to below detection in 2009. Total PAH
concentrations have decreased over time with concentrations in samples from 2000 (average
of samples taken from September to October from sites outside of the berm) ranging from 191
to 465 ng/L (Jaagumagi et al., 2001) compared to 12 to 141 ng/L in 2009.
Metals, Nutrients, and General Water Chemistry
Five metals exceeded their PWQOs: zinc, cadmium, aluminum, iron and chromium (Table 2).
Zinc and cadmium were elevated at NORREF2, although cadmium only exceeded the PWQO
when the uncertainty value was added. These metals were not elevated at the nearshore
sites, suggesting levels were impacted by offshore conditions in the harbour.
Aluminum exceeded the PWQO at six non-reference sites and was highest at NOR7 and
NOR8, in the northeast corner of the berm. As the aluminum results are based on unfiltered
7

15. samples, the values reflect both particulate and dissolved aluminum concentrations, and are
likely biased high.
Iron also exceeded the PWQO at NOR7 and NOR8 while chromium was at the PWQO at
NOR8 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 have
decreased at most sites and no longer exceed their PWQOs (Table 2).
General water chemistry was largely similar among sites (Table 3). Dissolved oxygen was
generally around 10 mg/L at the sites, with the exception of NOR6 (9.4 mg/L) and NOR9 (7.9
mg/L); all sites were above the 6 mg/L minimum that the PWQO requires. Total phosphorus
was slightly above the PWQO at NOR5 but was below it at all other sites (Table 3).
Sediment Chemistry
PAHs
Overall, concentrations of PAH compounds exceeded the LEL 45% of the time (118/260
possible exceedances) and the SEL 4% of the time (11/260). PAHs exceeded PSQGs at all
sites except NORREF1 (Table 4). Total PAH(16) levels in 2009 were highest at NOR6 (845,300
ng/g) and were above the SEL. Levels were much lower at the other sites, ranging from 2035
ng/g at NORREF1 to 194,040 ng/g at NOR4; however, levels still exceeded the LEL (4000
ng/g) with the exception of NORREF1 (Table 4, Figure 3).
Compared to sediment concentrations in 2004, PAH levels decreased by 76% at NOR6 and
97% 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 PAH
decreased by 63% between 2004 and 2007 and 34% between 2007 and 2009; however total
PAH remained above the SEL in 2009.
Reductions in total PAH at NOR6 and NOR8 were largely due to decreases in PAH
compounds associated with creosote, such as phenanthrene, pyrene, and fluoranthene (Figure
4). These PAHs were dominant in all sediment samples collected since 2004 (Figure 5) and
collectively accounted for 49 to 59% of total PAH at NOR6 and 32 to 58% of total PAH at
NOR8 from 2004 to 2009. The decrease in these creosote associated PAHs may be due to
their lower benzene ring number (≤ three) as these compounds are more susceptible to
weathering 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 compounds
exceeded their SELs over time (Figure 5). For example, nine PAH compounds, including the
creosote-associated compounds, exceeded their SELs at NOR8 in 2004 while all PAH
compounds were below their respective SELs in 2007 and 2009 (Figure 5b). At NOR6 there
has been a consistent decrease in the number of individual PAH compounds above the SEL
from 12 compounds in 2004, to 10 compounds in 2007, to eight compounds in 2009 (Figure
5a). These results suggest that PAH-associated impacts to the benthic community may have
decreased 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. due to those compounds with ≤ three benzene rings (i.e. phenanthrene, pyrene, and
fluoranthene, which are dominant in creosote; Figure 6b & c). The higher levels of lower ring
number PAH compounds may be related to mobilization away from areas where
concentrations 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 NOR4
supports this interpretation (Figure 7). Past studies have suggested that concentrations of
lighter, and hence more mobile, PAH compounds may increase away from source regions over
time (Murphy and Brown, 2005). Sediment concentrations of PAHs can vary, however, as
creosote was found to occur as distinct globules or lenses in the sediment (Jaagumagi et al.,
2001).
PCA of PAHs in Sediments
PCA explained 88.2% of the variation in PAH levels amongst the sites (Figure 8). Sites with
the highest levels of total PAHs are on the right-hand side of the ordination diagram. These
sites (NOR6, NOR4, NOR3) are characterized by relatively high levels of ≤ three ring number
PAHs, many of which are dominant in creosote. Sites plotted on the left-hand side of the
ordination diagram are characterized by higher relative levels of four to five ring number PAH
compounds. The close positioning of most sites on the left-hand side of the diagram to
NORREF1 and NORREF2 indicates similar PAH signatures at these sites. Only NOR11
appears to have a different PAH profile compared to the other sites as it had relatively high
levels of benzo(a)anthracene (BaA); this PAH accounted for 6.5% of total PAH at NOR11
compared to 3.8 to 4.9% of total PAH at other sites.
Metals
In total, eight out of 28 trace metals/metalloids exceeded PSQGs (Table 5, Figure 9). Of
these, only iron exceeded the SEL (40,000 µg/g). Iron was elevated above the SEL at most
sites, with the exception of the reference sites, NOR9 and NOR11. Previous studies have also
shown iron elevated above the SEL (Baker et al., 2006; Awad, 2009) likely due to regional
geology (Cannon et al., 2007). Iron levels appear to have increased somewhat since the
remediation; levels in samples collected outside of the berm were significantly higher in 2009
than in 1995 (p<0.05; Figure 10). This increase may be a result of dredging activities that
disturbed sediments containing naturally high iron or the locally quarried shale from the Great
West 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 of
the NWP site (Awad, 2009). In response, EMRB began monitoring arsenic in 2009 and found
that all sites were below the SEL. However, the highest arsenic concentration (23 µg/g) was
measured at NOR3 which is located just north of where Environment Canada reported high
levels (Table 5, Figure 9). The elevated arsenic near the NWP site is likely related to the
historical 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 the
reference 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 lower
at NOR11 compared to the other sites.
9

17. Similar levels of most metals between reference and non-reference sites have been reported
since 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 not
appear to be related to operations at the Northern Wood Preservers site.
Total Organic Carbon (TOC), Nutrient, and Particle Size
TOC exceeded the LEL (1%) but not the SEL (10%) at all sites, ranging from 1.1% at NOR11
to 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 remainder
consisting of clay (≤ 24%) and sand (≤ 15%) (Figure 11). Unlike the other sites, particle size at
NOR11 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 low
levels of metals were due to the greater proportion of sand at NOR11 as metals preferentially
sorb and concentrate in sediment with a finer grain than sand (Forstner and Wittman, 1983).
Mussels
Mussel mortalities of a single replicate occurred at NOR7, NOR8, and NOR9. Total PAH(16) in
mussels was elevated at four of the 13 sites (Table 6, Figure 12). Most of these sites were in
the 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 higher
levels 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 concentrations
were highest. The obvious contamination at this site (i.e. pungent odour, oil present on water
surface 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 NOR6
did not differ from that at other sites after the deployment (p>0.05), and no mortalities were
observed at NOR6, suggesting the three week exposure may have been too short to result in
an impact. Lack of uptake in mussels may also be due to water concentrations being below
detection limits at NOR6. However, mussel uptake was observed at NOR4, where sediment
concentrations were elevated and water concentration were also below detection limits.
Statistical differences among sites were not detected (p>0.05), possibly due to the small
sample sizes.
The detection of higher levels in the northeast corner is not unexpected, as this area is outside
of the berm and was left for natural recovery because PAH levels were relatively low and
considered 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) were
significantly (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. elevated in 2009 at NOR4 and NOR8 and the Kruskal-Wallis test showed a significant
difference among years (p<0.05), the difference was not great enough to be detected with the
post-hoc multiple comparison test. Similarly, although total PAH at NOR7 increased
considerably in 2009, the difference was not statistically significant (post-hoc multiple
comparison test, p>0.05). The lack of significance may be due to the small sample sizes and
high variation between mussels within a site. Large variability among replicates has been
previously 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 and
2009); 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 past
deployments; concentrations ranged from median levels below method detection (NOR2 and
NOR5) 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 2003
and 2004. Total PAH was below detection in all three mussels from each of the reference
sites, suggesting that PAH detections in the non-reference sites are related to historic
operations at the NWP site.
Elevated levels of total PAHs in mussels deployed in 2009 at NOR4 and in the northeast
corner were due to the same individual PAHs which were dominant in sediments:
phenanthrene, pyrene, and fluoranthene (Figure 13). These three PAHs, which are indicative
of creosote, accounted for 59 to 75% of total PAH at these sites. The natural weathering of
sediment since the remediation may be increasing the bioavailability of PAHs to mussels, and
resulting in elevated levels at sites in the northeast corner.
The variation in mussel uptake of PAHs between 2004 and 2009 makes it difficult to assess
temporal trends. Contaminant trends in mussels will be reassessed after the 2014 survey.
Sediment Toxicity Bioassays
A brief summary of the results of the toxicity bioassays is included here; see Appendix IV for
the complete summary (Watson-Leung & Simmie, 2011). Test validity, integrity of the test
system, organism health, and technician proficiency were confirmed for all four organisms
based on survival and growth in laboratory control sediments (Detroit River, Peche Island) and
reference toxicant testing (potassium chloride).
In the Hyalella azteca sediment toxicity test, mean survival was significantly lower than the
reference site at NOR6 (0%) and NOR4 (40±28%) (p<0.001). Mean survival was ≥94% at all
other sites. There were no apparent impacts on growth at any sites compared to the reference
site. In the Chironomus dilutus sediment toxicity test, significant impacts on mean survival
were observed at NOR6 (0%) and NOR4 (24%) (p<0.001). Mean survival was ≥74% at all
other sites. Growth of C. dilutus from NOR4 was 54% of reference growth, and was ≥81% of
reference growth at all other stations. In the Hexagenia sediment toxicity test, mean survival
was significantly lower than the reference site at NOR6 only (0%) (p<0.001). Mean survival
was ≥86% at all other sites. Hexagenia did not grow as well in the reference site as the
laboratory control, despite similar grain size and higher TOC in the reference sediment. Mayfly
growth was lower at NOR3, NOR4, and NOR8 compared to the reference site. For all three
tests, statistical significance of growth effects could not be assessed due to the lack of field
replicates (Environment Canada, 2005).
11

19. In the Fathead Minnow bioaccumulation test, mean survival was significantly lower than the
reference site at NOR6 (40±34%). Although statistical analysis showed a significant difference
between mean survival at NOR4 (88±13%) and the reference (100%), the high survival rate
indicates there was no biological impact. Surviving minnows from each treatment were
submitted for analysis of PAHs, lipids and, with the exception of NOR6 (due to insufficient
tissue), metals; BSAFs were calculated for PAHs only (Appendix IV, Table 5c). Uptake of
PAHs occurred at NOR3, NOR6 and NOR8, but the BSAFs at all sites were low (≤0.02). A
BSAF value less than one indicates that the contaminant has a greater affinity for sediment
over the organism, signifying that the contaminant is less bioavailable to the organism. A
BSAF greater than one indicates that the contaminant has a greater affinity for the organism
and that bioaccumulation has taken place.
PAH concentrations in exposed Fathead Minnows were highest at NOR6 and NOR8, and as in
past bioassays, phenanthrene, pyrene and fluoranthene, which are associated with creosote
contamination, were the major contributors. In some cases, PAHs in exposed fish from the
2009 sediment bioassays were lower than in the previous bioassay (2004), especially at NOR6
where lipid–corrected tissue concentrations of total PAHs decreased by 67%. At NOR4 and
NOR8, tissue concentrations were higher in 2009. At NOR3 and NOR10, exposed Fathead
Minnows accumulated PAH compounds that were not observed in tissue from the 2004
bioassay.
Metal concentrations were highest in the overlying water from the reference station in all tests
except for Hexagenia. Metals were also elevated in the overlying water from the laboratory
control 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 elevated
above the PWQO at NOR6 for the Fathead Minnow test only. In previous bioassays, metal
levels in overlying water did not correlate well with sediment concentrations or observed
toxicity (Trudy Watson-Leung, MOE, personal communication, 2011). PAHs were generally
highest in the overlying water from NOR4 and/or NOR6, where significant impacts on survival
of the exposed organisms was observed, indicating that PAH levels were the likely cause of
toxicity. PAHs were also higher in the overlying water from NOR4 and NOR6 as compared to
the 2004 bioassay.
Many metals exceeded the LEL in the sediment used in the toxicity bioassays, and in many
cases, levels were highest at the reference station (NORREF2), as was observed with the
overlying water. Arsenic was elevated above the SEL at NOR3 and iron was elevated above
the SEL at NOR3 and NOR5; no toxicity was observed at these sites. PAHs at all sites were
elevated above concentrations in the reference sediment, although some individual PAHs and
total PAH exceeded the LEL in the reference sediment. PAHs were highest in sediment from
NOR6 and NOR4, where impacts on survival and/or growth were observed. As analytical
results for the field sediment showed, total PAHs declined between 2004 and 2009 in the
laboratory sediment at NOR6 and NOR8 and increased at NOR3 and NOR4. Although
concentrations have declined at NOR6, they were considerably higher than at NOR4 which
was elevated compared to NOR8 and NOR3 (NOR6>>NOR4>>NOR8>NOR3), corresponding
to 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 sediment
and the laboratory sediment showed increases (13 to 67%) in the laboratory sediment from
12

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). In
addition, the sediment samples for the toxicity bioassays were collected to a depth of 10 to 15
cm in order to fulfill test volume requirements, whereas most benthic invertebrates typically
inhabit the top 5 cm of sediment (Jaagumagi and Persaud, 1993). Elevated levels due to
these factors likely result in an increase in the bioavailability of some contaminants that may
not be influencing organisms in the Thunder Bay Harbour. This is especially important at this
site, 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 the
most significantly impaired. Reduced survival was also observed in H. azteca and C. dilutus
exposed to NOR4 sediment in 2009, while survival was reduced for C. dilutus and Fathead
Minnow at NOR8 in 2004. This shift in impairment from NOR8 (2004) to NOR4 (2009) is likely
caused by the decrease in sediment concentrations at NOR8 and the increase in sediment
concentrations at NOR4 between 2004 and 2009.
The results of the 2009 sediment toxicity bioassays clearly indicate impaired survival for
organisms exposed to NOR6 sediment, as well as NOR4 sediment, in some cases.
Benthic Invertebrate Community Structure
Assemblage Composition and Benthic Metrics
In total, 114 species were identified across the 13 sites (Appendix III). Species belonged to 28
families and 15 orders. Most species belonged to three families: Chironomidae (midges; 38
species), 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; these
families were nearly ubiquitous and collectively accounted for 71 to 98% of total benthic
abundance (Table 8, Figure 14a). These families also dominated benthic communities in
previous studies (Jaagumagi et al., 2001; Baker et al., 2006).
Other families were present at fewer sites. Valvatidae (valve snails) were present at all but two
sites (NOR3, NOR11) while the remaining families were present at four to eight sites.
Asellidae (freshwater crustaceans) and Hydrobiidae (mud snails) were generally only present
at 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), only
Trichoptera was present. Baker et al. (2006) similarly found that Ephemeroptera and
Plecoptera 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 relative
abundance was low (≤ 2%) (Table 8, Figure 14b). The number of EPT species at each
individual 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 ± 170
individuals 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. sites (p>0.05), median abundance at NOR7 (71 individuals) was significantly less than
abundance at NOR10 (757.5 individuals) (p<0.05; Table 8, Figure 15a). High benthic
abundance at NOR10 may be related to its relatively shallow depth and aquatic vegetation
along the north side of the berm. The 1999 study also found that more abundant and diverse
communities near the berm were associated with the presence of aquatic vegetation near the
berm (Jaagumagi et al., 2001). Higher total benthic abundance may be related to increased
habitat types and food sources related to aquatic vegetation. Total benthic abundance
generally did not significantly differ between 2004 and 2009 except at NOR1 where abundance
decreased and NOR5 where abundance increased (p-values<0.05).
Median richness at the non-reference and reference sites averaged 24 ± 7 species and 29 ± 1
species, respectively. Although median richness ranged from 13 species at NOR6 to 33
species at NOR2 (Table 8, Figure 15b), differences between individual sites were not
significant (p-values>0.05). Between 2004 and 2009, richness significantly increased at
NOR2, NOR8, NOR9 and NOR10 (p-values<0.02). Median richness at these sites increased
by 10 to 18 species and richness in 2009 ranged from 29 to 33 species, similar to median
richness at the reference sites. Increases in median richness were largely due to increases in
the 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 would
have 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 at
NORREF2, 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 sites
north 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 sites
were dominated by midges, aquatic worms, and fingernail and pea clams. These organisms
are tolerant of organic pollutants and are common in areas with nutrient enrichment, poor
water 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 not
significantly differ among sites, nor did they differ between the non-reference and reference
sites. 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 exception
of low median richness at NOR6). These findings suggest background conditions in the
harbour 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), the
lack of statistical significance should be interpreted with caution.
14

22. Benthic Ordinations
PCA on the relative abundances of the eight common benthic families explained 96% of the
variation in benthic communities in 2009 (Figure 17).
Sites were primarily separated based on the relative abundances of aquatic worms (family
Naididae) and midges (Family Chironomidae). Sites to the right side of the ordination had
higher relative abundances of aquatic worms, whereas sites to the left side of the ordination
had higher relative abundances of chironomids (Figure 17). Sites were also separated based
on relative abundance of fingernail and pea clams (family Sphaeriidae) with sites to the top of
the ordination having higher relative abundances (Figure 17).
The benthic communities of the reference sites differed greatly with NORREF1 dominated by
midges (40% of total benthic abundance) and NORREF2 dominated by aquatic worms (79% of
total benthic abundance). NORREF1 also had much higher abundances of valve snails and
fingernail and pea clams.
Based on the relative positioning of sites, benthic communities in 2009 do not appear to be
distinguished based on PAH levels. For example, NOR6, which had the highest sediment
levels 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 significant
amount of the among-site variation in benthic communities, further suggesting the communities
are not significantly impacted by site-specific pollutant levels. Previous studies (Jaagumagi et
al., 2001; Baker et al., 2006) also found that differences among benthic communities could not
be attributed to the presence of PAH compounds. The lack of response of the benthic
community to PAH contamination may be the result of active organism avoidance as most of
the PAH is present as discrete blobs or drops of oil (Jaagumagi et al, 2001). Additional
sediment parameters examined in this survey (metals, ions, nutrients, total organic carbon,
and sediment particle size) did not significantly distinguish between the sites (as determined by
RDA).
SUMMARY AND CONCLUSIONS
PAHs were at low levels (below detection to trace) in all water samples collected from the
harbour. At NOR5, fluoranthene and pyrene, two compounds associated with creosote, were
elevated above CCME guidelines, but were still at trace levels. PAH concentrations in caged
mussels were mainly elevated in sites in the northeast corner (NOR7, NOR8, NOR10) as well
as at NOR4. Elevated PAHs at some of these sites likely reflect elevated concentration in the
sediment. Levels in mussels from NOR6 were low, even though the sediment concentrations
were highest at this site. PAH levels in mussels were significantly higher in 2009 than in 2004
at NOR9 and NOR10. Although a significant difference was not detected between years at
NOR4, NOR7, and NOR8, concentrations have increased considerably. PAH compounds
associated with creosote (phenanthrene, pyrene, and fluoranthene) were dominant in the
mussels from the sites with elevated sediment concentrations. Due to the variation in mussel
uptake of PAHs between 2004 and 2009, contaminant trends will be reassessed after the 2014
survey.
15

23. PAH concentrations continue to be elevated above provincial sediment quality guidelines at all
non-reference sites within the harbour. Concentrations were highest at NOR6, which
exceeded the SEL, followed by NOR4. PAHs have decreased considerably in sediment from
NOR6 and NOR8, mainly due to decreases in those compounds indicative of creosote
contamination (phenanthrene, pyrene, and fluoranthene), which are more susceptible to
weathering due to their lower ring number.
Sediment from NOR6 (highest total PAH concentration), caused 100% mortality of all test
invertebrates (Hyalella amphipods, Chironomus midges, and Hexagenia mayflies) as well as
significant mortality in the Fathead Minnows. Sediment from NOR4 (second highest total PAH
concentration), caused similar mortality levels to amphipods and chironomids. Similarly, in
2004, NOR6 sediments caused the most mortality. Exposure to NOR8 sediment did not cause
the impairments which were observed in 2004, likely due to decreases in sediment
concentrations at this site. Increases in sediment concentrations at NOR4, especially of those
compounds associated with creosote, may have resulted in the observed toxicity in 2009.
Despite elevated PAH concentrations in all non-reference sediments, especially NOR6, and
the reduced survival of benthic organisms exposed to some of those sediments during toxicity
bioassays (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 sites
were dominated by midges, aquatic worms, and fingernail and pea clams. Species richness
has 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 corner
was expected as this area is outside of the zone of remediation and was left for natural
recovery due to relatively low concentrations. Elevated PAHs as well as reduced survival of
laboratory organisms at NOR4 may be due to the mobilization of lower ring PAHs in creosote
from the northeast corner. As creosote contaminated sediment continues to break down,
similar changes in the contamination patterns may be observed. Laboratory bioassays reflect
maximum exposure, especially in this case as invertebrates in the harbour can likely avoid the
distinct lenses of contaminated sediment, so benthic invertebrate community structure may be
a better measure of the conditions in the harbour. Comparison of benthic invertebrate
community structure to reference stations suggests that background conditions in the harbour
have 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 marked
improvement in sediment concentrations of total PAHs since 2004. Concentrations remain
high (>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 as
well as NOR3, mainly due to increases in lower ring PAHs, likely a result of weathering of
sediments at sites in the northeast corner and mobilization of these compounds. Total PAHs
have increased in caged mussels deployed at some sites in the northeast 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 caged mussels.
The long-term monitoring plan, developed as part of the NOWPARC strategy, was intended to
assess the area outside the berm for impacts on aquatic life and to monitor natural recovery of
the sediment. As part of this monitoring plan, the final survey will be conducted in 2014, after
16

24. which, a full assessment of the recovery of the Northern Wood Preservers site will be made to
determine whether further work (monitoring and/or remediation) is recommended.
It is recommended that additional sites be sampled in the northeast corner and near NOR4
during the next monitoring survey (2014) to provide for enhanced spatial coverage. If possible,
replicate samples should be collected to enhance statistical analysis of differences (and
similarities) among sites. Dioxin compounds were initially identified as contaminants of concern
due to elevated levels found in the 1999 survey (Jaagumagi et al., 1996). Pentachlorophenol
was 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 these
compounds as they were elevated in the same areas as PAHs. It is recommended that these
compounds be analyzed in sediment from the 2014 survey to determine if remediation was
successful in decreasing the concentrations.
17

25. REFERENCES
Awad, E. 2009. Technical Memorandum: Northern Wood Preservers, 2007 Sample Summary. Sent
from Wolfgang Scheider to John Taylor. Ministry of the Environment.
Baker, S., R. Fletcher, and S.Petro. 2006. Northern Wood Preservers Alternative Remediation
Concept (NOWPARC) Bioassessment of Northern Wood Preservers Site Thunder Bay Harbour, Lake
Superior 2003 and 2004.
Beak, 1996. Preliminary assessment of long-term impacts associated with a NOWPARC remediation of
the 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 mercury
contamination in the Sudbury River, Massachusetts, using transplanted freshwater mussels (Elliptio
complanata). 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 the
Environment.
Bodnar, J. 2004. The determination of polynuclear aromatic hydrocarbons (PAH) in soil and sediments
by gas chromatography-mass spectrometry (GC-MS); method PSAPAH-E3350. Laboratory Services
Branch, Quality Management Section, Ministry of the Environment.
Canadian Council of Ministers of the Environment (CCME). 1999. Canadian water quality guidelines
for 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 sample
of the northern margin of the Penokean fold and thrust belt: U.S. Geological Survey Professional Paper
1730, 44 p.
Environment Canada. 2005. Guidance Document on Statistical Methods for Environmental Toxicity
Tests. EPS 1/RM/46. Ottawa, Ontario. 170 p.
Environment Canada. 2010. Laboratory Methods: Processing, taxonomy, and quality control of
benthic macroinvertebrate samples. Retrieved December 1, 2010, from Environment Canada Web
site: 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 and
Laboratory Analysis. Ministry of the Environment.
18

26. Jaagumagi, R., D. Bedard and S. Petro, 1996. Sediment and Biological Assessment of the Northern
Wood Preservers Inc. Site, Thunder Bay. July 1995 and September 1995. Ministry of the
Environment.
Jaagumagi, R., D. Bedard and R. Santiago, 2001. Northern Wood Inc. (NOWPARC) Post-Construction
Baseline 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. Cambridge
University Press, Cambridge, UK.
Marchant, R. 1989. A subsampler for samples of benthic macroinvertebrates. Bulletin of the Australian
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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 Ecotoxicological
Perspective (ed. P.E.T. Douben), John Wiley & Sons, Ltd, Chichester, UK.
MOE, 1994. Water Management Policies, Guidelines, Provincial Water Quality Objectives of the
Ministry 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 Treatment
with Creosote Compounds. Environmental Forensics 6: 151-159.
Persaud, D., R. Jaagumagi, and A. Hayton. 1993. Guidelines for the Protection and Management of
Aquatic 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 Sediment
Remediation Case Study. Presentation to the 2nd International Symposium on Contaminated
Sediments. Retrieved June 6, 2011, from: http://www.scs2003.ggl.ulaval.ca/Histories/Santiago2.pdf.
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Watson-Leung, T. and L. Simmie. 2011. Northern Wood Preservers, NOWPARC (Thunder Bay,
Ontario) Summary of Laboratory Toxicity and Bioaccumulation Test Results. Aquatic Toxicology
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Ter Braak, C.J.F. and P. Smilauer. 2002. CANOCO Reference manual and CanoDraw for Windows
User’s guide: Software for Canonical Community Ordination (version 4.5). Microcomputer Power
(Ithaca, NY, USA), 500pp.
19

27.
Figures

28. 21
a) 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. 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
N
Figure 2. Concentrations of select PAH compounds above detection limits over time in water samples from
Thunder Bay Harbour, near the NWP site. The two numbers following each site name indicate the year of
sample collection. Levels of pyrene and fluoranthene exceeded the CCME guidelines (25 ng/L for pyrene
and 40 ng/L for fluoranthene) at NOR5 in 2009.

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 N
Figure 3. Total PAH(16) measured in sediments from Thunder Bay Harbour, near the NWP site. Total PAH
above the site-specific SEL are marked with a red asterisk.

31. 24
a) NOR6 b) NOR8
Fluoranthene 2.0*105 Fluoranthene
8.0*105 Phenanthrene Phenanthrene
Pyrene Pyrene
PAH 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. 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.