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Niagara River Toxics
Management Plan (NRTMP) Reports
Progress Report and Work Plan -
June 2000
TABLE OF CONTENTS
The Niagara River flows 60 kilometres or 37
miles from Lake Erie to Lake Ontario. It serves as a source for drinking
water, fishing grounds, and vacation spots. It generates electricity and
provides employment to millions of people. Unfortunately, the River is
also the recipient of toxic wastes that pollute its waters and prevent us
from fully enjoying its beneficial uses.
Since 1987, the Niagara River has been the
focus of attention for the four environmental agencies in Canada and the
U.S., referred to here as "The Four Parties". In February 1987,
Environment Canada, the U.S. Environmental Protection Agency Region II,
the Ontario Ministry of the Environment and the New York State Department
of Environmental Conservation (the "Four Parties") signed a
"Declaration of Intent" (DOI). The purpose of the DOI is to
reduce the concentrations of toxic pollutants in the Niagara River.
Eighteen "priority toxics" were
specifically targeted for reduction, ten of which, because they were
thought to have significant Niagara River sources, were designated for 50%
reduction by 1996. The Niagara River Toxics Management Plan (NRTMP) is the
program designed to achieve these reductions.
In December 1996, the Four Parties signed a
"Letter of Support", pledging their continued commitment to
reduce toxic chemical inputs to the Niagara River, to achieve ambient
water quality that will protect human health, aquatic life, and wildlife,
and while doing so, improve and protect water quality in Lake Ontario as
well.
This year's Progress Report, in addition to
presenting results from the Upstream/Downstream and Biomonitoring
Programs, also presents information on the comparison of ambient water
concentrations to water quality objectives, fish consumption advisories,
and trends of contaminants in fish.
The Work Plan, also included as part of
this Progress Report, outlines the activities to be undertaken by the Four
Parties to achieve the goals expressed in the Letter of Support, and to
monitor and report progress towards attainment of these goals.
NYSDEC/EPA and MOE have previously
presented point source daily load data showing greater than 50% reductions
in the "priority toxics. NYSDEC and EPA have also presented
information on progress in remediation of hazardous waste sites. This
Progress Report presents evidence of progress, to gauge the effectiveness
of these actions. The key sources of information used in assessing
progress are:
-
Changes/trends in the
eighteen "priority toxics", determined by using a
statistical model and data from the Upstream/Downstream Program;
-
Biomonitoring Program data
(juvenile fish and caged mussels), indicating contaminant
bioavailability, one of the tools which can help us gauge the
effectiveness of remedial programs in reducing chemical inputs to the
Niagara River at various sources;
-
Comparison with the most
stringent agency water quality criteria available in 1996/97;
and,
-
Fish consumption
advisories.
The primary method of assessment is the
Upstream/Downstream Program. The program collects water and suspended
sediment samples once every two weeks from the head and mouth of the river
to measure the changes in the concentrations and loads of more than 90
chemicals. An advanced statistical model was used to determine trends for
the eighteen "priority toxics" for the period 1986/87 to
1996/97, and to determine with more certainty, the effectiveness of
reductions of chemical loads to the river.
Results show that there have been
statistically significant reductions in the concentrations and loads for
most of the eighteen "priority toxics". In many cases the
reductions have been greater than 50%. For some chemicals, the reductions
observed are due, in part, to the effectiveness of remedial activities at
Niagara River sources in reducing chemical inputs to the river.
In 1996/97, concentrations of most of the
"priority toxics" were below their 1996/97 most stringent agency
criteria. The exceptions were hexachlorobenzene (HCB) and the polynuclear
aromatic hydrocarbons (PAHs). This is a positive indicator of progress.
Recently, the New York State Department of Health has made some fish
consumption advisories in the Niagara River and Lake Ontario less
restrictive. Biomonitoring Program results, using caged mussels, continue
to show that remedial activities at specific hazardous waste sites have
been successful in reducing inputs of chemicals to the Niagara River.
Where the data show there might be some residual contamination, both EPA
and DEC have taken steps to ensure that appropriate follow-up action is
taken.
Each of the above results supports the
conclusion that remedial activities have had an effect in reducing the
loads of chemicals to the river. This is the overall goal of the Niagara
River DOI and the NRTMP.
Despite the successes to date, more work
needs to be done. Some chemicals are still at levels that exceed the most
stringent agency water quality criteria in the River. Advisories to limit
consumption of sportfish caught in the Niagara River continue due to
contamination by toxic substances. There is evidence of continuing sources
of chemical contamination in the River. Inputs from Lake Erie are also
important for some chemicals. The activities in the 2000 Work Plan reflect
the commitment of the Four Parties to continue to reduce toxic chemical
inputs to the River and to monitor the progress. This commitment includes:
- Completing the actions described in
prior NRTMP Work Plans;
- Ensuring that these actions have been
effective;
- Implementing additional actions to protect and restore the
River; and
- Continuing and improving the public reporting of progress.
In
February, 1987, Environment Canada, the U.S. Environmental Protection
Agency Region II, the Ontario Ministry of the Environment and the New York
State Department of Environmental Conservation (the “Four Parties”)
signed a "Declaration of Intent” (DOI).
The purpose of this Declaration is to achieve significant
reductions of toxic contaminants in the Niagara River.
Eighteen “priority toxics” were specifically targeted for
reduction (Table 1), ten of which, because they were thought to have
significant Niagara River sources, were designated for 50% reduction from
Canadian and U.S. point and non-point sources by 1996.
The Niagara River Toxics Management Plan (NRTMP) is the program
designed to achieve these reductions.
The NRTMP Work Plan identifies activities taken by the Four Parties
to remediate sources and to monitor progress toward protecting
the River.
The
Four Parties have used a variety of information to assess progress.
For example, NYSDEC/EPA and MOE have presented point source daily
load data showing greater than 50% reductions in the “priority
toxics”. NYSDEC and EPA
have presented information on
progress in remediation of hazardous waste sites.
Reductions in inputs of certain priority toxic chemicals to the
river from Niagara River sources have also been shown by ambient river and
biomonitoring data.
In particular, past NRTMP Progress Reports have focused on the
corroborative evidence from the Upstream/Downstream and Biomonitoring
programs, along with sediment core data from the Niagara River
depositional zone in Lake Ontario.
The information has been useful for assessing progress in meeting the 50%
reduction goal and in documenting successes in “cleaning-up” the
Niagara River. These reports
have presented at least two consistent messages as follows:
-
Concentrations
of many of the 18 NRTMP “priority toxics” in the Niagara River
have decreased and the river is getting “cleaner”; and,
-
Decreases
in the concentrations/loads of many of these “priority toxics”
have exceeded 50%.
Past
reports have also stated that, notwithstanding the work and successes to
date, more work still needs to be done.
Several examples of current concerns were noted in last year’s
report. These included
exceedences of water quality criteria in the river; fish consumption
advisories for fish from the river; and biomonitoring program results
indicating the continuing presence of particular priority toxics in areas
where remediations have occurred. Current
trackdown efforts will determine if there are sources of priority toxics
to the Niagara River that may require attention.
The
Four Parties are committed to further reducing toxic chemical inputs to
the Niagara River, and to assessing the effectiveness of remedial
activities at Niagara River sources in reducing the concentrations of
these chemicals in water and biota. In
December, 1996, the Four Parties signed a Letter of Support to re-affirm
their commitment to the NRTMP. The
revised goal statement in that Letter reads as follows:
To
reduce toxic chemical concentrations in the Niagara River by reducing
inputs from sources along the River. The purpose is to achieve ambient
water quality that will protect human health, aquatic life, and wildlife,
and while doing so, improve and protect water quality in Lake Ontario as
well.
In
addition to presenting results from the Upstream/Downstream and
Biomonitoring Programs, this year’s Progress Report presents additional
information on the comparison of ambient water concentrations to water
quality objectives, fish consumption advisories, and trends of
contaminants in fish.
The
Work Plan, also included as part of this Progress Report, outlines the
activities to be undertaken by the Four Parties to achieve the above goal,
and to monitor and report progress.
Since
1986, the Upstream/Downstream Program has been used to estimate the annual
mean concentrations and loads with their 90% confidence limits for each of
the chemicals, in both phases, at both stations. Results have been
summarized and released in annual, Four Party Upstream/Downstream reports
(e.g., NRDIG 1999).
The
Program collects both water and suspended sediment samples from the head
(Fort Erie = FE), and mouth (Niagara-on-the-Lake = NOTL) of the Niagara
River, once every two weeks1, to
measure the changes in the concentrations and loads of over 90 chemicals
in the water entering and leaving the river. Using state-of-the-art
sampling and analytical methodologies, the program has been able to detect
chemicals at very low concentrations - much lower than those allowed by
the detection limits used in source monitoring programs.
Both
seasonal and large, week to week, fluctuations in the Niagara River
Upstream/Downstream data made discernment of trends in the concentrations
and loads difficult. Compounding this difficulty was the fact that
the concentrations of many chemicals, particularly organic chemicals, were
so diluted (due to the river’s high rate of flow) that they were often
below analytical detection limits. Furthermore detection limits
changed during the period of record. To determine reliable trends
over time with known confidence for measured chemicals, a statistical
procedure was developed that dealt with “censored” and missing data,
auto-correlation and seasonality, as well as changing analytical limits of
detection (El-Shaarawi and Al-Ibrahim 1996).
A
detailed analysis of the Upstream/Downstream Program data collected over
the eleven-year period 1986/87 to 1996/97 to determine trends was recently
completed by Williams et al (2000). The model was run on each of the
chemicals, in each phase individually [whole water for metals], at both
stations for the entire period
of record.The ratio of the
means (expressed as a percent) for the end year (1996/97) to the base year2
was used to calculate an index of change over the eleven-year period of
record. Table 2 shows the percent change in the annual3
mean concentrations/loads for the 18 NRTMP “priority toxics”, in both
phases, at both stations, between the base year and end year (1996/97) generated
by the model. A dashed line
in the Table indicates that the chemical either had too few data to run
the model (e.g., most values below detection), or insufficient data to
have confidence in the model output. A positive number indicates a
significant increase, and a negative number a significant decrease, in the
model estimates of annual mean concentrations/loads between the base year
and 1996/97. “NS” signifies no significant change in the model
estimates over the period of record.
Briefly,
the results for the 18 NRTMP “priority toxics” show the following.
Chlorobenzenes (CBs)
The reduction in both the dissolved
and particulate phase concentrations and loads of hexachlorobenzene at
NOTL exceeded 50%. At FE, the output from the model was discarded
because significance was based almost entirely on “trace” (i.e.,
below the detection limit) values. This clearly suggests that
reductions at NOTL are due to reductions in the inputs of
hexachlorobenzene to the Niagara River from Niagara River sources.
Organochlorines
(OCs) and PCBs
In
general, both the concentrations and loads of nearly all the NRMTP
“priority toxics” OCs decreased significantly in one or both phases at
both FE and NOTL. Decreases were often observed only in one
phase because there were insufficient data in the other phase to determine
change. This may be related to the partitioning of the chemical
between the dissolved and particulate phases. The decreases (in
concentrations or loads) ranged between 23% (p,p’-DDE) and 83% (PCB) and
were, generally, of similar magnitude at both stations. Exceptions to
these generalities were "-chlordane, for which the trend was not
significant, and mirex which was detected only at NOTL.
Polynuclear Aromatic Hydrocarbons (PAHs)
Of
all the chemicals analyzed in the Upstream/Downstream Program, the PAHs
exhibited the most varied results. For those chemicals having
sufficient data to run the model, the concentrations and/or loads between
the base year and 1996/97 decreased for some, increased for others, and
for yet others, exhibited no significant change. Depending on the PAH,
these changes occurred only in the dissolved phase, only in the
particulate phase, or in both. Furthermore, changes for some PAHs
were significant at only one of the stations. For example,
benzo(a)pyrene B(a)P exhibited a significant increase in both
concentration and load only at FE over the eleven-year period.
Benzo(b/k)fluoranthene showed no significant change in either phase at
either station.
Industrial By-Product Chemicals
Octachlorostyrene
(OCS) was detected only at NOTL. The concentrations and loads of OCS
decreased significantly (>80%) in the particulate phase. There
were insufficient data in the other phase to determine change. As
noted for the OCs, this may be related to the different partitioning of
these chemicals between the dissolved and particulate phases. The
results clearly suggest success in controlling inputs from Niagara River
sources.
Metals
The
concentrations and/or loads of the three NRTMP “priority toxics”
metals at both FE and NOTL decreased significantly ranging from 3.1%
(arsenic) to >86% (lead).
Trend
Graphs
In
generating the output for Table 2, the model also generated time series
plots (i.e., trends) of the dissolved and suspended particulate phase
concentrations at both NOTL and FE for each of the “priority toxics”
shown in the Table. The plots for most of the chemicals showed a
statistically significant decrease. The pattern of change, however, was
not the same for all chemicals. In contrast, the plot for B(a)P showed an
increasing trend, while that for "-chlordane showed no significant
change/trend. Figures 1, 2,
3 and 4 are examples of the results for
hexachlorobenzene, PCBs, dieldrin and octachlorostyrene, respectively,
which exhibited a statistically significant trend over the 1986/87 to
1996/97 time period.
________________________________________
1
Prior to April 1997, sampling
was done on a weekly basis.
2
The base year varies for
different chemicals; while the program was initiated in 1986
(identified base year in the NRTMP), additional chemicals were added
to the Niagara River protocol as analytical methods became available.
3
Note that “annual” refers to April 1 to March 31, rather than
calendar year.
The
Niagara River is the largest tributary to Lake Ontario, providing over 80%
of all the water that flows into the lake. Along with the
contribution of water, the Niagara River also transports contaminants from
the waters of the upper Great Lakes and from sources along the river from
Lake Erie to Lake Ontario. Therefore, there is a critical link between the
inputs to the Niagara River from the upper Great Lakes, inputs from
sources along the river, and the water quality of Lake Ontario.
Improvements in both the Niagara River and Lake Ontario are related to
completion of site specific remediations, control of point source
discharges and encouragement of the implementation of pollution prevention
techniques. These improvements are evidenced by the results of the
Upstream/Downstream program, analysis of contaminant levels in the tissues
of fish or mussels and collection and analysis of sediments.
Inputs
of chemicals to the Niagara River can impact both the river and Lake
Ontario including, for example, contributing to the exceedences of water
and sediment quality criteria, and issuance of fish consumption
advisories. Surficial sediment chemical distribution patterns in Lake
Ontario point to the Niagara as a major source of many chemicals to
the lake (Thomas et al 1988). Similarly, depth distributions of
chemicals in dated cores collected from Lake Ontario in the vicinity of
the Niagara River mirror the production history of the chemicals (Durham
and Oliver 1983) and the reduction of Niagara River inputs, either as a
result of better control of sources along the length of the river, or
reductions in inputs from Lake Erie/upstream (Mudroch 1983; Stewart et al
1996). The six critical pollutants for the Lake Ontario Lakewide
Management Plan (LaMP) are also NRTMP “priority toxics” (Table
3).
Critical pollutants for Lake Ontario are chemicals which are causing
beneficial use impairments on a lakewide basis. The threat to
aquatic life and the real or potential impairment of beneficial uses such
as restrictions on fish consumption can be assessed by comparing the
Niagara River Upstream/Downstream Program data to available water quality
criteria.
Comparison
with Water Quality Criteria
The 18 NRTMP
“priority toxics” were selected based on their exceedence of water,
fish or sediment criteria in the Niagara River or Lake Ontario
(Categorization Committee 1990). It is appropriate, therefore, to
compare the current concentrations of these “priority toxics” in the
river to their criteria as an indicator of progress. Since its
inception, the NRTMP has used the most stringent agency criteria4
of either Canada, the United States, Ontario, or New York State (see
below).
The approach
used by the Four Parties in their annual Niagara River Upstream/Downstream
Reports (e.g., see NRDIG 1999) has been to compare the upper 90th
percentile recombined whole water (RWW) concentrations (i.e., dissolved +
particulate phases) of a chemical to the most stringent agency criterion
for that chemical. Using the upper 90th percentile, rather than the
annual mean, provides a more protective estimate of criteria exceedences.
This approach has also been used in this report.
Figures 5 and 6
show the results for the organochlorine (OCs) and polynuclear aromatic
hydrocarbon (PAHs) “priority toxics” at Niagara-on-the-Lake (NOTL) and
Fort Erie (FE), respectively. The most stringent agency criterion
concentration is noted for each chemical and is plotted as a solid line on
the graph when its concentration is reasonably close to the observed
chemical concentrations. Plotting NOTL and FE data on the same graph
facilitates comparison of the results at the two stations simultaneously.
Because none of the metals exceeded their criteria at either station the
data were not plotted. Briefly, the results show the following.
Of the OCs (Figure
5), only hexachlorobenzene (HCB) still exceeds its criterion at
NOTL. over the eleven years of sampling (1986/87 to 1996/97), the
magnitude of the exceedences has declined. PCB concentrations have
decreased since 1986/87 with concentrations in 1996/97 being below the
criterion for the first time over the eleven-year period.
For the PAHs (Figure 6), both benzo(b,k)fluoranthene and chrysene/triphenylene exceeded
the most stringent agency criteria at both FE and NOTL.
Benzo(a)pyrene has been above its criterion at NOTL for the past three
years and benz(a)anthracene has been slightly below its criterion for the
past six years.
The higher
concentrations for some of these chemicals (e.g., HCB, chlordane) at NOTL
infer the presence of inputs from Niagara River sources. The similar
concentrations of others (e.g., dieldrin, PCBs) at both stations, and the
higher concentrations of DDT and metabolites at FE, suggest that Lake
Erie/upstream is the major source. This is consistent with the
conclusions reached in past NRTMP Progress Reports.
In 1998, New
York State completed the adoption of water quality standards under the
U.S. Great Lakes Initiative. For some chemicals, these new standards
are now the most stringent of the Four-Party water quality criteria. For
example, the most stringent criterion for dieldrin was 0.9 ng/L and is now
0.0006 ng/L. Similarly, the most stringent criterion for PCB was 1.0
ng/L and is now 0.001 ng/L. New York State Water Quality Standards
are shown in BOLD in Table 4. Future NRTMP Progress Reports will
compare the data collected beginning in 1998 to these new criteria.
It is also worth
noting that ambient “priority toxics” concentrations already are below
many of the most stringent agency criteria for other categories such as
the protection of drinking water, protection of aquatic life, etc. (Table
4).
Notwithstanding
the above, two additional points should be noted. First, despite the
low concentrations of contaminants in the Niagara River, the high flow of
the river (>5300 m3/sec) means that it may still be contributing
substantial loads of contaminants to Lake Ontario (Mudroch and Williams
1989). Given the persistence of many of these chemicals, this means that
there may still be the potential for problems in Lake Ontario related to
Niagara River inputs and other upstream sources for some time to come.
Lastly, it was
mentioned briefly in last year’s report that some chemicals
(particularly the PAHs), not currently considered “priority toxics”,
also exceeded their strictest agency criteria in the river. For
example, Figure 7 shows that fluoranthene and benzo(ghi)perylene have
consistently exceeded their criteria at both NOTL and FE since they were
first measured. Anthracene also exceeded its criterion about half
the time over the last eleven years. As noted above (Section 2.0),
the river data on PAHs is particularly complex. The NRS will be
reporting further on these chemicals in 2001.
Comparison of
the ambient concentrations of “priority toxics” in water to the
strictest agency criteria in use in 1996/97 clearly indicates progress.
As noted, however, the criteria for a number of chemicals were made even
more stringent in 1998. Continuing work will need to be done
to ensure that concentrations of these chemicals in the river are
eventually below these new agency criteria.
Fish
Consumption Advisories
New York State
and Ontario issue advice regarding consumption of sport fish caught in
their waters.
The
New York State Department of Health (NYSDOH) issues an annual booklet
titled
Health Advisories: Chemicals in Game and
Sportfish.
This booklet provides advisories on eating sportfish and game since some
of these foods contain chemicals at levels that may be harmful to human
health. The health advisories provide general advice on sportfish
taken from the waters in New York State and on game species. The
information is presented so that it is easy to understand the guidance for
a particular species from a specific waterbody. The advisories
explain how to minimize exposure to contaminants from sportfish and game
and reduce whatever health risks are associated with them.
NYSDOH
has a general advisory to eat no more than one (half-pound) meal per week
of sportfish from all New York State fresh waters (and some marine waters
at the mouth of the Hudson River). The United States federal
government sets standards for chemicals in food that is sold commercially,
including fish. In New York State, the Department of Environmental
Conservation (NYSDEC) monitors contaminant levels in fish and game.
NYSDOH issues specific advisories (i.e., “eat none” or “eat no more
than one meal per month”) when sportfish have contaminant levels greater
than federal standards. NYSDOH also advises women of
childbearing age, infants and children under the age of 15 to eat no fish
from waters that have specific advisories for any fish species.
For
the Niagara River and Lake Ontario system, specific sportfish advisories
have seen some important changes in the past several years. In 1999,
the previous advisory (all species, “eat none”) for Gill Creek from
the Hyde Park Dam downstream to its mouth on the Niagara River was removed
based on new data showing lower PCB levels in black crappie, largemouth
bass, white perch, brown bullhead and bluegill. Contaminated
sediment was removed from Gill Creek before the fish were sampled.
The current advisory for the upper Niagara River and tributaries of “eat
no more than one meal per month of carp” now also applies to Gill Creek
In 1998, NYSDOH made advisories for certain sizes of rainbow trout, lake
trout and coho salmon from Lake Ontario and the lower Niagara River less
restrictive because of lower concentrations of PCB and mirex in more
recent collections of these fish. The 1998/1999 New York State
advisories for the Niagara River are summarized in Table
5.
NYSDEC
staff will be analyzing data to evaluate temporal trends in contaminant
concentrations in fish from the Niagara River. It is known, however, that
between 1993 and 1996 most contaminant concentrations in sportfish from
Lake Ontario (central and eastern sections) have generally declined,
especially PCBs and mirex. Several factors are probably responsible for
these changes. First, management actions implemented in the late
1970s and the 1980s (e.g., chemical production bans, use restrictions,
improvements in waste water treatment, and the remediation of hazardous
waste sites) have reduced PCB and mirex inputs to the lake. Also,
the biotic community continues to undergo dramatic changes based, at least
in part, on the introduction of exotic species. These community
changes may be changing the dynamics of contaminant uptake by fish through
alterations in the food web.
Similarly,
the Ontario Ministry of the Environment issues advice contained in the
biennial
Guide to Eating Ontario Sport Fish. Consumption advice on a
total of 18 species of fish from two locations on the Niagara River is
included in the
Guide. The consumption advice is based on health
protection guidelines developed by Health Canada. Table 5 is taken
from the 1999-2000 Guide (MOE 1999). The consumption table shows less
restrictive consumption advice for chinook salmon, rainbow trout and lake
trout in the lower Niagara River than the 1997-1998
Guide. Elevated
concentrations of mercury, PCBs, and mirex/photomirex continue to be the
major contaminants causing Ontario consumption advisories for the sport
fish found in the Niagara River.
In
1999, northern pike and smallmouth bass were collected in the upper
Niagara and walleye and smallmouth bass in the lower Niagara River.
In 2000, a broad range of species will be collected from both the upper
and lower Niagara River. The results will be available for the 2001
NRTMP Progress Report and for the 2001/02 Guide to Eating Ontario Sport Fish.
Historical
data from the MOE Sport Fish Contaminant Monitoring Program are currently
being analyzed to evaluate temporal trends in contaminant concentrations
in sport fish from the upper and lower Niagara River and western
Lake Ontario. Sport fish from western Lake Ontario have
been included because their contaminant concentrations appear to reflect
the concentrations found in lower Niagara River sport fish.
Temporal
trends for PCB concentrations in the edible portion of lake trout and
chinook salmon from western Lake Ontario are shown in Figures 8 and
9, respectively. PCB concentrations in both species declined
substantially between the 1970s and mid-1980s. Reductions in PCBs
after 1983 appear to be modest.
Trends
of PCB in Lake Ontario Fish
The
statement above for trends of PCB in edible portion of lake trout can be
compared with the trends for whole fish shown in Figure 10 based on
several data sets and the estimated trend based on the LOTOX (Lake Ontario
Toxics) model. Despite the differences among the data sets, a
continuing trend of PCBs in fish is indicated. For example, Huestis
et al (1996) using a data set which is internally consistent, concluded
that from 1977 to 1993, most measured contaminants showed significant
decreasing trends. The LOTOX model simulation for PCB concentrations
in lake trout based on estimates of the PCB loads to the lake reinforces
this conclusion.
________________________________________
4 Although criteria have changed over the period of record of the
NRTMP,
in this report, all data were compared to the most stringent agency
criteria available in 1996/97.
Many chemicals can concentrate in the
tissues of aquatic organisms and reveal the presence of contaminants that
cannot otherwise be directly detected in water, because of dilution. Since
1980 the Ontario Ministry of Environment (MOE) has conducted both routine
and specialized biomonitoring of contaminants in the Niagara River using
caged mussels (Elliptio
complanata) as part of Ontario's
commitment to the NRTMP. The principle behind the mussel biomonitoring
program is to take mussels (biomonitors) from an uncontaminated site and
place them in an environment that is known or suspected of being
contaminated with persistent bioaccumulative substances. The biomonitors
are left for a specified time to accumulate contaminants and are then
analysed to determine tissue contaminant concentrations. The Biomonitoring
Program has provided information on suspected contaminant sources and
source areas in the river between Fort Erie and Niagara-on-the-Lake.
In 1997 mussels were deployed at 32
stations on the American as well as Canadian side of the river. In
general, results indicated spatial distributions of contaminant
concentrations in mussel tissue similar to those observed since 1980. On
the Canadian side of the river, mussels had no detectable concentrations
of chlorinated benzene compounds, PCBs or organochlorine pesticides, with
the exception of trace concentrations of p,p'-DDE (a metabolite of the
pesticide DDT).
On the U.S. side of the river,
organochlorine pesticides were detected sporadically at several stations
at concentrations similar to those in past surveys. Mirex was detected in
mussels deployed at sites associated with the Occidental Chemical
Corporation. PCBs and chlorinated benzene compounds were detected at
almost all stations. Hexachlorobenzene, pentachlorobenzene and
1,2,3,4-tetrachlorobenzene were the most frequently detected chlorinated
benzenes.
After completion of remedial activities at
the 102nd Street hazardous waste site in December, 1998, mussel
tissue concentrations of almost all parameters were below the detection
limit. This was in contrast to high tissue concentrations of these
compounds observed prior to site remediation. In particular, dioxin and
furan concentrations in mussels deployed at 102nd Street
Landfill were low and reflect the success of the site remediation and
removal of contaminated sediment. Figure 11 shows the dioxin data for the
period 1987-97. No dioxins and furans were detected in the sediment sample
collected from the site.
Concentrations of dioxins and furans in
exposed sediment at the Niagara River shoreline at the mouth of Bloody Run
Creek, which runs through the Hyde Park hazardous waste site, although
lower than pre-remediation concentrations, were still high relative to
sediment concentrations observed throughout the Great Lakes basin.
Characteristic of the congener/isomer patterns for Bloody Run Creek all
the tetra-dioxin was in the form of 2,3,7,8-tetrachlorodibenzo-p-dioxin
which is the most toxic form of dioxin (45,000 pg/g). The presence of
dioxins and furans in mussels at this site suggest that these compounds
were bioavailable to aquatic life at this location (Figure
12). The TEQ
(concentration of toxicity equivalents) for Bloody Run Creek sediment was
58,543 pg/g. Toxicity Equivalency Factors (TEQs) are used as a measure to
express the toxicity of different dioxins and furans on a common basis.
TEQs are assigned to individual dioxins and furans on the basis of how
toxic they are in comparison with the toxicity of
2,3,7,8-tetrachloro-dibenzodioxin, which is assigned the value of 1.0.
2,3,7,8-TCDF is one tenth as toxic and has a toxic equivalent of 0.1. This
site is under further investigation by EPA. It should be noted that follow
up sediment sampling by EPA in 1999 at the mouth of Bloody Run Creek also
indicated possible continuing concerns due to dioxin contamination. EPA
will assess the human health risk of the contamination. A more detailed
characterization of the area will be performed.
It is also important to note that the
monitoring at the base (mouth) of Bloody Run does not adequately reflect
the effectiveness of the Hyde Park Landfill remedial systems. The remedial
plan for the Niagara gorge face was based on human-health exposure
scenarios. The remedial systems in place to date have been successful in
drying up the gorge-face seeps and have substantially reduced chemical
loadings from the site into the river. However, the area of the Bloody Run
within the gorge was not remediated and residual contamination exists. The
Hyde Park settlement agreement recognized that there would be residual
contamination. To limit human exposure, access to the area is restricted.
Concentrations of chlorinated benzenes in
mussels deployed at the Pettit Flume inlet cove were low relative to
previous years of sampling before the remediation of the cove in 1994 (Figure
13). By removing contaminated sediment from the cove, an important
non point source of chlorinated benzenes and phenols to the Niagara River
was eliminated. However, high concentrations of dioxins and furans were
detected in mussels and sediment. Given the recent extensive remedial
activities at this site, the source of the dioxins and furans is unclear.
The congener patterns in the sediment and mussel sample were consistent
with samples from 1993 before remedial activities suggesting a common
source. Figure 14 shows the dioxin and furan isomer patterns in caged
mussels from the Pettit Flume for 1993 and 1997. NYSDEC is presently
investigating possible sources and the extent of contamination in the
cove. The high concentrations in mussel tissue showed that these compounds
were still bioavailable in this cove. Fish, other aquatic biota and
waterfowl move freely in and out of the cove to feed and sediment is
transported from the cove to the Little Niagara River. All these factors
suggest that dioxins and furans in this cove were bioavailable to the
Niagara River. Concentrations of 2,3,7,8 T4CDD in sediment from the Pettit
Flume site were 350 pg/g and the TEQ for the Pettit Flume cove sediment
was 20,073 pg/g.
Recent sampling of sediment in the Pettit
Cove has confirmed the presence of dioxin and furans indicative of
Occidental Chemical, Durez. However, due to the absence of volatile
organic chemicals (VOCs) within the recently deposited sediment, it is
hypothesized that the contamination is an historical remnant of past sewer
cleaning operations within the Pettit Flume and not a new source. In
response, Occidental Chemical has mobilized a remedial contractor to
conduct maintenance dredging of the Pettit Cove. Approximately, 200 cubic
yards of sediment will be hydraulically dredged out of the cove in spring
2000.
Dioxins and furans were not detected in
mussels deployed at Fort Erie on the Canadian side of the river. Sediment
concentrations of dioxins and furans at the Fort Erie site were low and
similar to concentrations measured in sediment in 1995 from Fort Erie. The
TEQ for Fort Erie was 11.3 pg/g.
The mussel monitoring program will be
repeated in July 2000.
The messages in this Progress Report
reiterate the consistent messages of the past few Progress Reports.
Specifically, these are that:
- Concentrations of many of the 18 NRTMP
"priority toxics" in the Niagara River have decreased and
the river is getting "cleaner"; and,
- Decreases in the concentrations/loads of
many of these "priority toxics" have exceeded 50%.
The "priority toxics" were
selected based on their exceedence of water, fish or sediment criteria in
the Niagara River or Lake Ontario (Categorization Committee 1990).
Comparing the current concentrations of these "priority toxics"
in the river to the 1996/97 most stringent agency criteria as an indicator
of progress shows that only hexachlorobenzene and some of the PAHs still
exceed their criteria at NOTL. Decreasing concentrations over the last
eleven years, however, has resulted in the magnitude of the exceedences in
1996/97 being less than what they were in 1986/87. Furthermore, decreasing
PCB concentrations since 1986/87 have resulted in concentrations in
1996/97 being below the criterion for the first time over the eleven-year
period. These are positive indicators of progress. Data from the New York
State Department of Health shows that some of the recent fish health
advisories in the Niagara River and Lake Ontario have become less
stringent. This is due, at least in part, to the beneficial remedial
efforts at Niagara River and Lake Ontario sources. Data from the
Biomonitoring Program, using caged mussels, continue to show that remedial
activities at specific hazardous waste sites have been successful in
reducing inputs of chemicals to the Niagara River. Where the data show
there might be residual contamination occurring, both EPA and DEC have
taken steps to ensure appropriate follow-up action is taken.
There have clearly been successes under the
Niagara River Toxics Management Plan and progress continues to be made.
This is the overall purpose of the NRTMP and the Letter of Support signed
by the Four Parties in December, 1996, to re-affirm their commitment to
the NRTMP.
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Environment Canada, the United States Environmental Protection Agency,
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Environmental Conservation.
DePinto, J.V., T.C. Young, and W.G. Booty.
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Burlington, Ontario.
Huestis, S.A., M.R. Servos, D.M. Whittle,
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Ontario. J. Great
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Niagara River. J.
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NYSDOH. 1998. Health Advisories, Chemicals
in Sportfish and Game, 1998-1999. New York State Department of Health.
Revised September 1998.
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