Niagara Falls: from honeymoon to Love Canal and back by RR Roll

Wasteland to parkland: the Cherry Farm/River Road Remediation by JG Goeddertz, JH Kyles, MS Raybuck

Niagara River toxics 2000 by Niagara River Secretariate

Involving youth in water quality issues by J Spisiak

Remedial action plans in Lake Ontario Basin

Coarse monomedia filtration: a solution to wet weather flow by BT Smith and KM Miller

Water resources management history project by RD Hennigan

Managing Mercury in Erie County by MC Rossi

People and places

President's message by AJ Zabinski

Executive director's report by P Cerro-Reehil

WEF news

Fall 2000 — Vol. 30, No. 3


Niagara River toxics 2000

Excerpts adapted from "Niagara River Toxics Management Plan" by the Niagara River Secretariat, June 2000

Quick reference
- Summary
- Upstream-downstream monitoring
Web extra: Graphs of trends in chemical concentrations.
- Status and trends relative to objectives
- The biomonitoring program
- References


  • Concentrations of many of eighteen priority toxics in the Niagara River have decreased and the river is getting cleaner
  • Decreases in the concentrations/loads of many of these priority toxics have exceeded 50%.

The priority toxics were selected based on their exceeding water, fish, or sediment criteria in the Niagara River or Lake Ontario (Categorization Committee 1990). Comparing the current concentrations of these 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 Niagara-on-the-Lake. Decreasing concentrations over the last 11 yr, however, have resulted in the magnitude of the exceedences in 1996-97 being less than those 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 11 yr. These are positive indicators of progress.

Data from the NYSDOH show 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 USEPA and NYSDEC have taken steps to ensure appropriate follow-up action is taken. Details are below.

The Niagara River flows 37 mi from Lake Erie to Lake Ontario. It is a source for drinking water, fishing grounds, and vacation spots; it generates electricity and provides employment to millions of people. The River is also the recipient of toxic wastes that pollute its waters and prevent residents from fully enjoying its beneficial uses.

Lower Niagara River flowing northward through the Niagara Gorge (photo by Richard R. Roll)

Since 1987, the Niagara River has been the focus of attention for the four environmental agencies in Canada and the U.S. In February 1987, Environment Canada, the USEPA Region 2, the Ontario Ministry of the Environment, and the NYS Department of Environmental Conservation agreed to reduce the concentrations of toxic pollutants in the Niagara River.

Eighteen priority toxics were targeted for reduction, ten of which, because they were thought to have significant Niagara River sources, were designated for 50% reduction by 1996 (see Table 1). The Niagara River Toxics Management Plan (NRTMP) is the program designed to achieve these reductions. Efforts have been underway to reduce eighteen priority toxic chemicals 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. See Table 1.

Table 1.
  Designated for 50% reduction by 1996
chlordane PCBs
dieldrin mirex/photomirex
DDT and metabolsites hexachlorobenzene
toxaphene dioxin (2,3,7,8-TCDD)
arsenic Mercury
lead tetrachloroethylene
octachlorosstyrene benz(a)anthracene
chrysene/triphenylene benzo(a)pyrene

Results show that statistically significant reductions in the concentrations and loads for most of the eighteen priority toxics have occurred. 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 NYS Department of Health has made less restrictive some fish consumption advisories in the Niagara River and Lake Ontario. 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 USEPA and NYSDEC have taken steps to ensure that appropriate follow-up action is taken.

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 sport fish caught in the Niagara River continue because of 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.

Upstream-downstream monitoring

Since 1986, the Upstream/Downstream Program has estimated the annual mean concentrations and loads for several chemical. The Program collects both water and suspended sediment samples from the head and mouth of the Niagara River once every two weeks to measure the changes in the concentrations and loads of over ninety 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 (because of the 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).


Time-series plots (trends) were also generated to display the dissolved and suspended particulate phase concentrations at both Niagara-on-the-Lake and Fort Erie for each of the priority toxics. The plots for most of the chemicals showed a statistically significant decrease. The pattern of change, however, was not the same for all chemicals.

 Web extra: Graphs of trends in chemical concentrations.

Status and trends relative to objectives

The Niagara River is the largest tributary to Lake Ontario, providing over 80% of the Lake's 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. There is a critical link, therefore, 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 remediation projects, 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.

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).

Comparison of the ambient concentrations of priority toxics in water to the strictest agency criteria in use in 1996-97 clearly indicates progress.

Upper rapids of the Niagara River near Goat Island

Comparison with water quality criteria

Of the organochlorine compounds, only hexachlorobenzene still exceeds its criterion at Niagara-on-the-Lake over the 11 yr of sampling (1986-87 to 1996-97), and the magnitude by which the samples have exceeded criteria has declined. PCB concentrations have decreased since 1986-87 with concentrations in 1996-97 being below the criterion for the first time over the 11 yr. For the polyaromatic hydrocarbons, both benzo(b,k)fluoranthene and chrysene/triphenylene exceeded the most stringent agency criteria at both Fort Erie and Niagara-on-the-Lake. Benzo(a)pyrene has been above its criterion at Niagara-on-the-Lake for the past 3 yr and benz(a)anthracene has been slightly below its criterion for the past 6 yr.

The higher concentrations for some of these chemicals (for example HCB, chlordane) at Niagara-on-the-Lake infer the presence of inputs from Niagara River sources. The similar concentrations of others (for example dieldrin, PCBs) at both stations, and the higher concentrations of DDT and metabolites at Fort Erie suggest that Lake Erie-upstream is the major source. This is consistent with the conclusions reached in past.

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. 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 and protection of aquatic life.

These reductions notwithstanding 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/s) 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.

Second,    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, fluoranthene and benzo(ghi)peryiene have consistently exceeded their criteria since they were first measured. Anthracene also exceeded its criterion about half the time over the last 11 yr.

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. NYS Department of Health has a general advisory to eat no more than one meal per week of sport fish (0.5 lb) 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, NYSDEC monitors contaminant levels in fish and game. NYSDOH issues specific advisories when sport fish 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 sport fish 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. 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 sport fish 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 (for example chemical production bans, use restrictions, improvements in wastewater 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.

Temporal trends for PCB concentrations in the edible portion of lake trout and chinook salmon from western Lake Ontario declined substantially between the 1970s and mid-1980s. Reductions in PCBs after 1983 appear to be modest.

The biomonitoring program

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 has conducted both routine and specialized biomonitoring of contaminants in the Niagara River using caged mussels (Elliptio complanata). 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 analyzed 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 thirty-two 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 now and then 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 before 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. 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. 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. The 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 USEPA. It should be noted that follow up sediment sampling by USEPA in 1999 at the mouth of Bloody Run Creek also indicated possible continuing concerns because of dioxin contamination. USEPA 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. By removing contaminated sediment from the cove, an important nonpoint 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. 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-TCDD 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, because of the absence of volatile organic chemicals in the recently deposited sediment, it is hypothesized that the contamination is a historical remnant of past sewer cleaning operations in 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 yd3 sediment will be hydraulically dredged from 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.


Categorization Committee. 1990. Categorization of Toxic Substances in the Niagara River. A Joint Report of Environment -Canada, the United States Environmental Protection Agency, Ontario Ministry of the Environment and New York State Department of Environmental Conservation.

Durham, R.W., and B.G. Oliver. 1983. History of Lake Ontario contamination from the Niagara River by sediment radiodating and chlorinated hydrocarbon analysis. J. Great

El-Shaarawi, A.H., and Al-Ibrahim. 1996. Trend Analysis and Maximum Likelihood Estimation of Niagara River Data (1986 -1994). National Water Research Institute and McMaster University, Burlington, Ontario.

Mudroch, A., and D. Williams. 1989. Suspended sediments and the distribution of bottom sediments in the Niagara River. J. Great Lakes Res. 15(3):427-436.

Mudroch, A. 1983. Distribution of major elements and metals in sediment cores from the western basin of Lake Ontario. J. Great Lakes Res. 9(2):125-133.

Stewart, J., F. Estabrooks, and R. Bopp. 1996. Lake Ontario Sediment Survey: 1995 Sediment Coring Results. Bureau of Watershed Management and Research, New York State Department of Environmental Conservation (November 1996).


Home   |  Masthead |  Author's guide |  Advertisers |  Scholarship fund
Executive Director     Editor     Webmaster
To speak with a representative: 1-315-422-7811