Lake Ontario Sediments as Indicators of the Niagara River as a Primary Source of Contaminants

Past studies on the distribution of mercury, PCB, and mirex in the surficial bottom sediments of Lake Ontario have clearly indicated the significance of the Niagara River as a major source of contaminants to the lake. The distributions have further indicated the net transport of sediment-bound materials in the lake which has assisted in the general understanding of the occurrence of contaminants at many trophic levels in the Lake Ontario ecosystem. Mean concentrations of a number of elements in suspended solids centrifuged from the Niagara River in 1974 further indicated that the river is also a major source for chromium, cadmium, vanadium, and arsenic, and a lesser though significant source of lead, copper, and nickel.     

Distribution of Mercury,Trace Organics,and Other Heavy Metals in Detroit River Sediments

In 1980 the Ontario Ministry of the Environment carried out a surficial bottom sediment survey of the Detroit River. The survey was designed to update changes in sediment mercury levels from a 1970 study, and to determine the spatial distribution of trace organics and other heavy metals as a baseline for future investigations. The contamination of sediments along the Ontario shoreline of the river was localized near known inputs such as Little River, the West Windsor sewage treatment plant, Turkey Creek, and Riviere aux Canards. Almost the entire U.S. shoreline sediments exhibited elevated levels (above provincial dredging guidelines) of contaminants such as heavy metals and PCBs. Levels of one order of magnitude higher than those on the Canadian shore were prevalent along the U.S. shore. Mercury levels exhibited a substantial decline during the period 1970–1980. Increases in chromium, copper, lead, and zinc in the vicinity of the mouth of the Rouge River along the U.S. shoreline during the same period suggest both recent and continuing inputs from industrial and municipal sources.     

The Niagara River mussel biomonitoring program (Elliptio complanata): 1983-2009

The Ontario Ministry of the Environment has monitored the concentrations of contaminants in mussel (Elliptio complanata) tissue and bottom sediments at sites in the Niagara River since 1983 to describe the general contamination of the river and identify contaminant sources. More recently, the data have been used to document the effectiveness of remedial actions implemented at identified sources along the river. Results from Canadian sites and five U.S. sites at which remedial actions have been implemented [Bloody Run Creek (Hyde Park Hazardous Waste Site); Gill Creek; Occidental Chemical Company (Buffalo Avenue Plant); 102nd Street Hazardous Waste Site; and Pettit Flume Cove] are discussed. p,p′-DDE, PCBs and dioxins were the only contaminants detected at Canadian sites at concentrations probably representative of background. Results from the five sites showed the effectiveness of implemented remedial actions in reducing the flow of contaminants to the river ranged between very effective (Gill Creek: PCBs; and 102nd Street, CBs) to no effect (Bloody Run Creek: PCBs, CBs, and dioxins). Remedial actions at the Pettit Flume Cove (for dioxins/furans) initially appeared to be effective, but were subsequently shown to have missed a source to the cove. The effectiveness of the actions taken at these sites in improving contaminant conditions in the Niagara River since the 1980s as demonstrated by our mussel and sediment results is corroborated by the data from other fish and water quality monitoring programs. Additional remedial efforts are still required at these sites and other known sources of contaminants to the river.     

Compartmental Distribution of Organochlorine Contaminants in the Niagara River and the Western Basin of Lake Ontario

Ten chlorobenzenes, hexachlorobutadiene, and PCBs were measured in Niagara River water and suspended solids, and in western Lake Ontario sediments and benthic fauna. High levels of these contaminants were found on all fractions of the river suspended solids, but the larger particles contained much higher concentrations than the smaller particles. A portion of the CBs, HCBD, and PCBs present in the lake sediments was available to benthic organisms. A trend toward greater bioaccumulation for compounds having higher octanol-water partition coefficients was observed at all trophic levels.     

Organic Contaminants in the Suspended Sediments of the Niagara River

Suspended sediment samples were collected approximately every 2 weeks from the Niagara River at Niagara-on-the-Lake between April, 1979 and April, 1980. Three other samples were collected from the Fort Erie end of the river during July, 1979. All samples were analyzed for organochloride pesticide residues.Of the residues tested, PCB was the most prevalent, followed by DDT, mirex, chlordane, methoxychlor, and endosulfan. The Niagara River is apparently the largest single source of PCBs to Lake Ontario. Comparison with other work indicates that the loadings of total PCBs from this source have more than doubled since 1968.Evidence suggests that much of the suspended sediment contaminated with PCB, mirex, and p,p′-DDT emanates from sources which enter the Niagara River between Grand Island and Niagara-on-the-Lake.     

Monitoring metal and persistent organic contaminant trends through time using quagga mussels (Dreissena bugensis) collected from the Niagara River

Historically, the Niagara River received the discharge of persistent bioaccumulative and toxic chemicals from municipal and industrial outfalls and hazardous waste landfills. American and Canadian governments have coordinated investigations of chemicals entering the river and initiated remedial measures and monitoring programs with a goal to reduce loadings of toxic chemicals to the river. This study, a component of the Ontario Ministry of Environment Mussel Biomonitoring Program, compares contaminant concentrations in quagga mussels (Dreissena bugensis) collected from nine locations in the Niagara River in 1995 and 2003 to assess anticipated changes in tissue concentrations of contaminants in response to ongoing remedial efforts by government agencies and local industries. The concentrations of persistent organic compounds (e.g., PCBs, hexachlorobenzene, hexachlorobutadiene, octachlorostyrene) in quagga mussels in 2003 were lower than concentrations measured in 1995, consistent with a decrease in reported mean annual concentrations of these compounds in water. Significant differences in total PCB concentrations in mussels between stations (F = 4.6; P < 0.001) suggested sources of PCBs on the American side of the upper Niagara River. In general, highest concentrations of persistent organic compounds were found downstream of the Occidental Chemical Corporation Buffalo Avenue facility suggesting local sources of these contaminants notwithstanding remedial efforts. In contrast, metal concentrations in quagga mussels in 2003 were similar to concentrations found in 1995 and to values reported in the literature for mussels collected from industrialized areas in the Great Lakes. Overall, our results suggest that remedial efforts to improve water quality in the Niagara River have been successful.     

The Influence of the Niagara River on Contaminant Burdens of Lake Ontario Biota

Top predator and forage fish species, netplankton (> 153 μm), zooplankton, and benthic macroinvertebrates from Lake Erie and Lake Ontario were analyzed for whole body levels of trace metals and organic contaminants. Comparison of contaminant concentrations in similar aquatic food chains from both lakes indicated that levels of PCB, DDT, mirex, and mercury are significantly greater (P <0.05) in the biota of Lake Ontario. The Niagara River, the single largest tributary to Lake Ontario, was confirmed as a major source of organic contaminants and trace metals. Organic contaminants are adsorbed to the particulate load of the river and dispersed throughout Lake Ontario by the circulating currents. There was no significant regional difference (P<0.05) in the degree of contaminant accumulation by the pelagic food chain of Lake Ontario. Conversely, both inorganic and organic contaminant levels in the demersal amphipod, Pontoporeia affinis, were significantly different (P<0.05) between the eastern and western basins of Lake Ontario. The uptake and concentration of contaminants at the sediment-water interface is suggested as a possible mechanism to explain this observed difference.     

Biological Monitoring of Organochlorine Contaminants in the St. Clair and Detroit Rivers Using Introduced Clams, Elliptio Complanatus

Introduced clams (in cages) were effective biomonitors in determining the distribution, biological availability, and source areas of a number of chlorinated organic contaminants in the St. Clair River-Detroit River corridor during 1982 and 1983. In the St. Clair River, hexachlorobenzene (HCB), octachlorostyrene (OCS), pentachlorobenzene (QCB), hexachlorobutadiene (HCBD), 2,3,6-trichlorotoluene (TCT), and alpha-BHC were most frequently identified in tissues after 3 weeks’ exposure. When compared to other locations in the St. Clair and Detroit rivers, significantly (p<0.05) higher levels of QCB, HCB, OCS, and HCBD were found in clams exposed along the Sarnia to Corunna, Ontario, shoreline. Elevated concentrations of HCB and OCS were also detected in water samples from this section of the river. TCT was found in clams from most locations, at low levels, with no obvious source area. Low levels of polychlorinated biphenyls (PCBs) were restricted to clams from the Sarnia area. In the Detroit River, PCBs, HCB, and OCS were most frequently detected in clams. PCB levels were significantly (p<0.05) higher along the Michigan shore and the highest concentrations were found in the Rouge River area. PCBs were also detected in some water samples from urbanized areas of the river. HCB and OCS were found at near-detection levels in clams from most stations. Contaminant levels in clams from around Fighting Island were low or non-detectable, indicating an absence of biologically available organochlorine contaminants in this area of the river. In the St. Clair River, p,p-DDE was only detected in the Sarnia area, whereas it was found in clams from both sides of the Detroit River, also at low levels. Aldrin, chlordane, and DDT were only sporadically detected in both rivers.     

Preliminary Assessment of Contaminants in Soft Sediments of the Detroit River

Soft sediments from the Detroit River were analyzed for the USEPA priority pollutants to generally characterize contaminant distribution. Forty-three were detected. Highest heavy metal concentrations were found in the Trenton Channel and immediately downstream of Grosse Ile. They ranged from an area mean (N = 2) of 0.19 mg/kg mercury to 338.7 mg/kg zinc (dry weight). Polynuclear aromatic hydrocarbons ranged from 0.1 mg/kg to 38.8 mg/kg (mean, N = 2) with the highest levels near Grosse Ile. PCBs ranged from 0.015 mg/kg to 1.7 mg/kg (mean, N = 2). Organochlorine pesticides were not detected except for a trace of heptachlor in one sample. Sediment contamination in the Detroit River is widespread with higher concentrations on the U.S. side downstream of the Rouge River and in the Trenton Channel. The significance of these in-place pollutants to biota and as a source to Lake Erie is still unknown.     

A River-wide Survey of Polychlorinated Biphenyls (PCBs), Polycylic Aromatic Hydrocarbons (PAHs), and Selected Organochlorine Pesticide Residues in Sediments of the Detroit River—1999

The spatial distribution of hydrophobic organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and octachlorostyrene (OCS) in sediments of the Detroit River was established using data from a 1999 river-wide survey. The survey employed a stratified random sampling design that divided the river into six geostatistical zones consisting of upper, middle, and lower U.S. and equivalent Canadian river reaches. Organic carbon normalized OCS sediment concentrations demonstrated no significant differences between U.S. or Canadian sediments or upstream/downstream gradients suggesting that OCS is derived primarily from sources upstream of the Detroit River. In contrast, sum PCBs and sum PAHs were significantly elevated at U.S. as compared to Canadian stations and demonstrated significant increasing upstream/downstream gradients in organic carbon normalized sediment contamination. The upper and middle U.S. river reaches contained a number of near-shore stations with high localized PCB and PAH sediment concentrations suggesting multiple inputs along the upper U.S. portion of the river. Consistent with past surveys, wide-spread sediment contamination of PCBs and PAHs continues to be observed in the highly industrialized Trenton Channel and downstream of Grosse Isle. Threshold effect level (TEL) sediment quality guidelines for PAHs and PCBs were exceeded in 92.6 and 77.8%, respectively, of stations in Trenton Channel and downstream of Grosse Isle. This large reservoir of degraded sediments in the lower U.S. river reach has the potential to enter Lake Erie during sediment disturbance events and likely contributes to gentoxic stress and increased bioaccumulation of PCBs in resident benthos, fish, and wildlife.     

The Impact of Sediment-Associated Contaminants from the Niagara River Mouth on Various Size Assemblages of Phytoplankton

The impact of elutriated sediment-associated contaminants from the Niagara River mouth and from a midlake station in Lake Ontario on various size assemblages of natural phytoplankton was determined. The C¹⁴ fractionation bioassays indicated that the addition of Chelex-treated elutriate (without dissolved metals) from the Niagara River mouth enhanced the C¹⁴ uptake when compared to the standard elutriate. Conversely, at the midlake station, the addition of standard elutriate (with dissolved metals) induced higher C¹⁴ uptake than the Chelex-treated elutriate. It is apparent that the synergistic effects of nutrients/metals and metals/organic compounds determine the bioavailability and toxicity of contaminants to natural phytoplankton. Our technique is sensitive and useful in detecting the differential response of algal size fractions to contaminants.     

Chlorinated Organic Contaminants in Water and Suspended Sediments of the Lower Niagara River

Suspended sediment and raw water samples have been collected and analyzed for organochlorines and PCBs from a fixed location in the lower Niagara River at Niagara-on-the-Lake approximately weekly since 1979. Eight of the 19 organochlorine compounds measured were detected in more than 50% of the water samples analyzed, while 11 of the 19 compounds were detected in more than 50% of the suspended sediments collected at Niagara-on-the-Lake. Of the 10 chlorobenzene isomers measured, the one with the greatest usage (1, 4-dichloro) occurs in largest concentrations in the suspended sediments at Niagara-on-the-Lake. Other chlorobenzene isomers commonly occurring in suspended sediments are 1, 2 and 1, 3 dichloro, 1, 2, 4-trichloro, 1,2, 3, 4-tetrachloro, pentachloro, and hexachloro. All isomers of chlorobenzene occurred in more than 70% of the suspended sediment samples collected. Total loadings to Lake Ontario calculated from these data indicate that PCB loadings are about twice as high as previously reported, while mirex and total DDT hate decreased slightly. Although concentrations of contaminants in suspended sediments are usually higher than those measured in water samples, they are responsible for only about 40% of the total loadings for PCBs, DDT, and HCB, and significantly less for other organochlorine contaminants. Therefore, the data indicate that, to estimate total contaminant loadings, the water fraction must be sampled. Lake Erie is not the major source of such organic contaminants as PCBs and chlorobenzenes because contaminant levels in Lake Erie bottom sediments are 10 times lower for PCBs and 20 times lower for chlorobenzenes than in Niagara-on-the-Lake suspended sediments.     

Biomonitoring of Bioavailable PAH and PCB Water Concentrations in the Detroit River Using the Freshwater Mussel,Elliptio complanata

Bioavailable PAH and PCB water concentrations were evaluated along the Detroit River using the freshwater mussel, Elliptio complanata. Bioavailable concentrations ranged from 64.2 to 620.7 ng/L for ΣPAHs and 0.1 to 3.0 ng/L for ΣPCBs. A principal component analysis grouped contaminants primarily on the basis of hydrophobicity, indicating that physical-chemical properties regulate the relative concentrations and distributions of PAHs and PCBs among sites. Concentrations of the more hydrophobic PAHs and more water soluble PCBs were present at elevated concentrations at the Detroit Edison Generating Station, in the Trenton Channel. Elevated PAH levels were also detected at three other sites: West Windsor Sewage Treatment Plant, Grassy Island, and Ambassador Bridge, along the Detroit River. This study supports the conclusion that E. complanata is an effective biomonitor of water PAH and PCB concentrations in aquatic systems. In addition, the results indicate that areas of high contamination in the Detroit River are a result of continued loading of these chemicals into the Great Lakes system.     

Organic Priority Pollutants in Nearshore Fish from 14 Lake Michigan Tributaries and Embayments, 1983

Composite, nearshore, whole fish samples of selected species, collected in fall 1983 from 13 Lake Michigan tributaries and Grand Traverse Bay, were analyzed for a wide range of pesticides and priority pollutants using gas chromatography-mass spectrometry. This study was carried out to identify existing source areas for known and previously unrecognized toxic substances. Our strategy was to analyze those resident fish with the highest likely levels of contaminants. All fish analyzed (eight species from southern Michigan to the upper peninsula) exceeded the 2 mg/kg FDA action levels for PCBs, while 50% of the samples exceeded the DDTr IJC objective of 1 mg/kg. St. Joseph River common carp (Cyprinus carpio) carried the heaviest contaminant burden of all fish examined for PCBs (27.6 mg/kg), DDTr (10.2 kg/mg), and toxaphene (3.3 mg/kg); chlordane levels (0.85 mg/kg) were second highest to those in Kalamazoo River common carp (0.87 mg/kg). Concentrations of PCBs, toxaphene, DDT, DDE, and other pesticides were higher in bottom-feeding fish, such as common carp, than in top predators, e.g., northern pike (Esox lucius). Bottom feeders are relatively fatty fish, and live and feed near contaminated sediments, which increases their potential to bioaccumulate fat-soluble contaminants. Pesticides were also present in elevated concentrations in fish from sites with higher industrial and agricultural development.     

History of Lake Ontario Contamination from the Niagara River by Sediment Radiodating and Chlorinated Hydrocarbon Analysis

Contamination of Lake Ontario by persistent organic compounds began with the development of the chemical industry along the Niagara River. These compounds are discharged to the river where they are scavenged from the water column by sedimenting particulates which in turn settle out in depositional areas of Lake Ontario. We have determined ²¹⁰Pb, ¹³⁷Cs, and chlorinated hydrocarbon profiles of sediment cores taken about 3 km from the mouth of the Niagara River. Age profiles of the sediments were constructed from the radionuclide measurements and used to determine historic trends of chlorinated hydrocarbon input to Lake Ontario. The historical record found in the sediments for chlorobenzenes, chlorotoluenes, hexachlorobutadiene, octachlorostyrene, mirex, and PCBs is in good agreement with known production and usage patterns of the chemicals. Pollution of Lake Ontario with chlorinated hydrocarbons from the Niagara River is still occurring, but the worst contamination of the lake occurred in the 1960s.     

Partition of metals in the Vistula River and in effluents from sewage treatment plants in the region of Cracow (Poland)

The Vistula River suffers from heavy pollution with multiple origins. In the upper reaches, metallic and chlorine pollution originates from the mining and industrial region of Upper Silesia. Downstream from Upper Silesia, urban and industrial sewage adds more metallic and organic contaminants from the large urban agglomeration of Cracow. Although the river status is monitored routinely, little is known about the partition of metals between particulate and dissolved forms. This study focuses on metal partitioning and on the impact of the two main wastewater treatment plants at Cracow on metal concentrations in the Vistula River. The Cd, Co, Cu, Mn, Pb and Zn content was measured in both dissolved and particulate fractions. High metal concentrations in the Vistula River persist, although current levels seem to be lower than those in the past. Metal concentrations in the Vistula River and effluents from the sewage treatment plants at Cracow are similar, indicating a relatively minor contribution from the treated sewage. However, untreated sewage may be a significant source of contaminants. Despite high anthropogenic metal concentrations, the metal partitioning coefficients (K_d) in the Vistula are similar to these found in unpolluted rivers. Within a narrow pH range, K_d values depend on the metal affinity to particles, but there is no evidence of dependence on particle or chloride concentrations. An important fraction of the toxic metals Pb and Cd is associated with particles, which may decrease their immediate availability to the biota of the river.     

It goes with the flow: Size mediated plankton attenuation through the Niagara River connecting channel

The Niagara River connecting channel provides a unique system in which to examine the impact of a rapid lentic-lotic-lentic transition on a freshwater ecosystem, particularly on plankton community composition. From June to October 2014, six monitoring sites (three in the upper river and three in the lower river) were sampled monthly for water chemistry, phytoplankton and/or zooplankton composition. Zooplankton biomass decreased exponentially with distance downstream, as expected within a high flow lotic environment. The rapid attenuation of zooplankton occurring within 10?km of the river mouth was likely due to predation by large populations of planktivorous fishes in the river. Densities of phytoplankton, rotifers and bacteria also declined but were less strongly impacted by the lentic-lotic transition. Plankton communities were dominated by species common to Lake Erie, the source waterbody, and also by taxa more resilient to the highly turbulent conditions of the river. These species included siliceous diatoms, filamentous algae, small zooplankters, dreissenid veligers and loricated rotifers. Furthermore, the seasonality of species composition in the Niagara River is the same as its source water body, suggesting no impact from the river on plankton succession. Niagara Falls and the two hydroelectric facilities were not found to be a significant cause of plankton mortality down river. There is some evidence however that entrainment time in the hydroelectric reservoirs may slightly enhance phytoplankton and zooplankton densities, thus contributing to plankton populations downstream of the turbine discharges.     

Environmental Impact of Two,Adjacent, Hazardous Waste Disposal Sites in the Niagara River Watershed

Sediment core samples were taken from the Niagara River at locations adjacent to the Love Canal and the 102nd Street dumps, two hazardous waste disposal sites in the City of Niagara Falls, New York. The samples were analyzed by capillary gas chromatographic mass spectrometry, and a variety of halogenated organic compounds (including chlorobenzene, -toluene, -naphthalene, -benzyl, and -norbornane derivatives) were identified and quantified. Based on the qualitative and quantitative data obtained, the sources of these pollutants were identified, and the relative migration of chemicals from the two dumps to the Niagara River was established. The impact on the river is localized to the immediate vicinity of the outfall of the sewer draining the Love Canal neighborhood. Remedial action could be as easy as removing 20 truckloads of contaminated sediment from the river.     

Factors Affecting Metal Partitioning During Resuspension of Sediments from the Detroit River

The release of previously deposited substances from sediments may represent a significant source of contaminants to the overlying water. Of special concern is the partitioning between aqueous- and sediment-phase heavy metals in response to resuspension events induced by hydrodynamic forces. In this paper results from a set of field experiments are reported in which sediment cores from three stations in the Trenton Channel of the Detroit River were artificially resuspended. Statistical analysis of the data indicated that the concentrations of the dissolved metals Cd, Co, Cu, Ni, Pb, and Zn in the overlying water varied inversely with pH (p<.05) and directly with time when the pH was below 7.5. In addition, dissolved metals were consistently lower at the higher frequency of mixing. Only Zn showed a direct correlation between total and dissolved concentrations although all other metals revealed an increased positive correlation at the higher mixing rate. These results are interpreted in terms of surface sorption reactions, particle size distributions, and mass transfer controls on metal-sediment reaction rates.     

Evidence of successful river spawning by lake trout (Salvelinus namaycush) in the Lower Niagara River,Lake Ontario

Restoration of a wild-produced lake trout Salvelinus namaycush population in Lake Ontario has not been successful despite the adult population often meeting or exceeding restoration targets. Lack of high-quality spawning habitat in Lake Ontario is suggested as one impediment to recruitment of wild lake trout, although the quantity and location of spawning habitat is poorly understood. If high-quality spawning habitat is limited in Lake Ontario, lake trout may be using uncommon spawning locations such as rivers. Anecdotal angler accounts point to the Niagara River as a lake trout spawning location. To better understand the potential of the Niagara River as a spawning location, egg and juvenile fish collections were conducted 12–14 river kilometers from the mouth of the Niagara River from 2010 to 2012; and mature female lake trout with surgically implanted acoustic tags were monitored from 2015 to 2019. Genetic analyses confirmed 60% of collected eggs and 93% of collected post-hatch juvenile fish in the Niagara River were lake trout. Tagged female lake trout returned to the Niagara River over consecutive years during the spawning season. The short duration of lake trout presence in the river (mean = 56 days/year) suggests female lake trout use the Niagara River primarily for spawning. Diversity in spawning locations may provide lake trout population’s resilience against environmental variability through a portfolio effect. Improved identification of riverine spawning locations, including their overall contribution to wild recruitment, may be a useful tool for managers to restore a wild-produced population of lake trout in Lake Ontario.