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.     

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.     

Studies of Trace Contaminants,Nutrients, and Bacteria Levels in the Niagara River

Sediment and water quality of the Niagara River were investigated during 1979 and 1980 to determine spatial and temporal differences in the levels of trace contaminants (heavy metals, phenolics, PCBs, and organochlorine pesticides) as well as nutrients and bacteria. Data from these studies as well as recent biomonitoring studies indicate that the Niagara River continues to be a source of such contaminants as PCBs, BHCs, mirex, and heavy metals to Lake Ontario. The major source of the contaminants is the highly industrialized and urbanized Tonawanda Channel area in the upper section of the river. Although a substantial improvement in phenolics levels was noted in the river since earlier surveys in 1971, bacterial and phosphorus levels show no significant changes, particularly near the U.S. mainland shore of the Tonawanda Channel and near the Buffalo River mouth.     

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.     

Assessing impaired benthic communities using sediment toxicity and contaminant concentrations from reference sites inside the Niagara River Area of Concern

Anthropogenically degraded benthic-macroinvertebrate communities (benthos) are one of seven beneficial use impairments (BUIs) in the Niagara River Area of Concern (AOC). Over the last 50 years, upgrades to waste-water treatment, industry closures, and sediment remediations reduced contaminant levels throughout the system. Improvements in benthic communities and sediment toxicity, however, were difficult to assess because there are no comparable reference reaches outside the AOC. A multi-phase study was initiated in 2015 to determine if data from inside the AOC could identify reference conditions, if toxicity and benthic-community data from these sites differed from other AOC sites, and if further remediation efforts were warranted in parts of the AOC. Concentrations or quotients of PAHs, PCBs, dioxins and furans, pesticides, and most metals were below their New York Sediment Class A Guidance Values at 10 sites that were subsequently designated as reference sites. Survival and growth data from Chironomus dilutus and Hyalella azteca bioassays indicated that sediments from only a few individual AOC-impact sites were toxic or significantly different from reference sites, and that mean toxicity at pooled AOC-impact and reference sites did not differ significantly. Similarly, New York Biological Assessment Profile scores and chironomid mentum deformity scores at only a few individual sites differed significantly from corresponding indices at reference sites, but neither metric differed significantly in comparisons between pooled AOC-impact and reference sites. Most analyses indicated that benthic communities were unimpaired and that removal criteria for the benthos BUI were largely met in much of the upper Niagara River AOC.     

Trace Organic Contaminants in the Detroit River

Concentrations of polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PNAs), chlorobenzenes (CBs), chlorophenols (CPs), and a number of other organochlorine compounds (OCs) have been determined in the surface microlayer, subsurface water, suspended solids, sediments, and in sediment pore water at 20 sampling stations in the Detroit River. The data are discussed in terms of contaminant sources, pathways, and sinks. Spatial trends within the river and relationships of contaminant groups within and between compartments are described. The results indicate a continuing input of all contaminant groups to the river from a variety of sources, particularly from sewage treatment plant effluents and several tributaries. The contaminant distributions and intercorrelations also indicate that major sources of PCBs, PNAs, OCs, and CBs are concentrated on the westerly river shore, while CPs enter the river mainly from the easterly shore.     

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.     

Condition of resident fish communities in the Eighteenmile Creek Area of Concern,New York

The lower 3.5 km of Eighteenmile Creek, a tributary to Lake Ontario in New York, was designated as an Area of Concern (AOC) in 1985 under the Great Lakes Water Quality Agreement due to extensive contamination of bed sediments by polychlorinated biphenyls (PCBs) and other toxicants. Five beneficial use impairments (BUIs) have been identified in this AOC, including degraded fish and wildlife populations. We surveyed fish communities in the Eighteenmile Creek AOC and in a comparable section of a nearby reference stream (Oak Orchard Creek) during June 2019 to infer whether legacy contaminants are currently impairing fish communities in the AOC to an extent that they differ from the regional reference condition. Estimates of community abundance, biomass, diversity, and fish condition from each system were compared using a noninferiority testing framework. Biomass, diversity, and fish condition in the Eighteenmile Creek AOC were similar or superior to that in Oak Orchard Creek, while abundance was 20% lower in the AOC. These findings and those of a 2007 sampling effort suggest that fish communities in the Eighteenmile Creek AOC are not impaired despite recent studies indicating that PCBs are bioaccumulating in fish tissues at 1–2 orders of magnitude above background levels. Future assessments in the Eighteenmile Creek AOC might focus on the condition of benthic macroinvertebrate communities and potential toxicity of local contaminants to piscivorous wildlife in order to fully address the remaining aspects of the fish and wildlife populations beneficial use impairment.     

Organochlorine Contaminant Residues in Spottail Shiners (Notropis Hudsonius) from the Niagara River

Collections of young-of-the-year spottail shiners (Notropis hudsonius) were used to determine spatial distribution (1981) of organochlorine residues and their temporal trends in the Niagara River. PCB and mirex residues in spottail shiners ranged from 164 to 573 ng/g and ND-18 ng/g, respectively. PCB and mirex residues exceeded the aquatic life objectives (Great Lakes Water Quality Agreement of 1978) at all sites except Frenchman's Creek, where mirex was non-detectable. Residues for heptachlor, heptachlor epoxide, aldrin, endrin, chlordane, thiodan, dieldrin, BHC, and DDT were low or non-detectable in Niagara River spottail shiners. Chlorinated benzene and octachlorostyrene residues were also present in most Niagara River spottail shiner samples analyzed. Dioxin (2,3,7,8- TCDD) was present in all Niagara River spottail shiner collections and ranged from 4 to 60 pg/g. The highest dioxin residues were found at Cayuga Creek, N. Y. PCB residues have declined significantly since 1975 in Niagara-on-the-Lake spottail shiners; however, residues increased in 1980 and 1981, although they were below the 1975 concentrations. Mirex residues in spottail shiners from Niagara-on-the-Lake have also declined significantly since 1978, suggesting reduced mirex inputs to Lake Ontario.     

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.     

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.     

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.     

Biological monitoring and pollution assessment of the Mukuvisi River,Harare, Zimbabwe

The ecological health and biodiversity of the Mukuvisi River system were investigated during this brief study to assess the functioning of the natural river system, utilizing biological monitoring. The study covered a period of 5 weeks from 15 September to 12 October 2005, during which a weekly sampling routine was conducted, and the effects of pollution on the river were investigated. The pH, dissolved oxygen concentration, temperature and electrical conductivity, as well as the two major nutrients in the water (phosphorus; nitrogen) were measured at four sites along the Mukuvisi River. Macroinvertebrate species also were identified and enumerated at each site, using the South African Scoring System version 4 (SASS4) to assess the biological diversity and to evaluate pollution levels at each site. Site 2 was the most polluted, while site 4 was the cleanest site. It was concluded that, although the river receives pollutants along its course, it also has a self‐purification capacity that can be enhanced by remedial measures against pollution. Possible remedial actions are discussed as recommendations in this study.     

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.     

Sediment Lead Loads in the Niagara River, 1986–1992

The problem of estimating sediment lead loads from Lake Erie to the Niagara River and from the river to Lake Ontario is considered. Using weekly data for the period 8 May 1986 to 12 October 1992, autoregressive time series models containing terms for trend and seasonality were developed for the average daily load at the head (FE) and mouth (NOTL) of the river, as well as for the load ratio and difference between the two sites. The estimated average load at the Fort Erie station decreased dramatically from 230 kg/day in 1986 to a roughly constant level of approximately 87 kg/day thereafter, the lowest value of 74 kg/day being reached in 1992. At the Niagara-on-the-Lake station, daily load declined gradually throughout the measurement period, from 110 kg/day in 1986 to 65 kg/day in 1992. Thus, by 1992, there was little difference (9 kg/day) in the loads at the two sites, suggesting that the major contribution of sediment lead to the Niagara River was from Lake Erie.     

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.     

Tracking River Plumes with Volatile Halocarbon Contaminants: The Niagara River—Lake Ontario Example

The concentrations of six predominant volatile halocarbon contaminants CCl₄, total and industrial CHCl₃, CHBrCl₂, CH₂Cl₂, CFCl₃, and C₂Cl₄ in epi- and hypolimnetic lake waters are used to demonstrate tributary plumes and nearshore currents on the Lake Ontario/Niagara River example. The relative speed and sensitivity of the analysis for volatile halocarbons provides for a synoptic view of the major currents at the time of sampling. For example, the individual distributions of several contaminants indicate the existence of a Niagara River surface water plume in northerly direction for approximately 8 km into the lake. In contrast, the predominantly east-west isostats of the contaminant concentrations in the hypolimnetic water indicate little direct influence by the Niagara River and show the existence of other contaminant sources in these areas.     

Historical Monitoring of Biomarkers of PAH Exposure of Brown Bullhead in the Remediated Black River and the Cuyahoga River,Ohio

Biomarkers of exposure to chemical contamination, benzo[a]pyrene (BAP)- and naphthalene (NAPH)-type metabolites, were measured in brown bullhead from a heavily polycyclic aromatic hydrocarbons (PAHs) contaminated section of the Black River, Ohio, during and immediately after remedial sediment dredging in 1990–1991, and in follow-up revisits in 1993 and 1998. Biomarker levels of bullhead from the historically polluted Cuyahoga River and the protected Old Woman Creek National Estuarine Sanctuary in Ohio were also measured over the same time periods. PAH-bile metabolite concentrations of bullheads from the Black River were still elevated in the year following dredging, but were significantly lower in the later resampling years. Metabolite concentrations of Cuyahoga River bullhead decreased significantly between 1991 and 1993, possibly in response to the shutdown of coking operations on the river. Fish from Old Woman Creek showed some variation in metabolite concentrations among periods, but were consistently lower than the other two rivers at each time. Measurement of bile metabolites proved an effective tool for estimating changes in exposure over time and among sampling sites. Trends in biomarkers indicated lowered exposures in the Black and Cuyahoga Rivers. These findings are likely a result of remediation activities in the Black River and source reduction and incidental sediment displacement in the Cuyahoga River.     

Contaminant-associated health effects in fishes from the Ottawa and Ashtabula Rivers,Ohio

The health of resident fishes serves as a biologically relevant barometer of aquatic ecosystem integrity. Here, the health of the Ottawa River and Ashtabula River (both within the Lake Erie Basin) were assessed using morphological and immunological biomarkers in brown bullheads (Ameiurus nebulosus) and largemouth bass (Micropterus salmoides). Biomarker metrics were compared to fish collected from a reference site (Conneaut Creek). Data utilized for analyses were collected between 2003 and 2011. Fish collected from all three river systems had markedly different contaminant profiles. Total PCBs were the dominant contaminant class by mass. In bullhead, PCBs were highest in fish from the Ashtabula River and there were no differences in fish collected pre- or post-remediation of Ashtabula Harbor (median = 4.6 and 5.5 mg/kg respectively). Excluding PCBs, the Ottawa River was dominated by organochlorine pesticides. Liver tumor prevalence exceeded the 5% trigger level at both the Ashtabula (7.7%) and Ottawa Rivers (10.2%), but was not statistically different than that at the reference site. There was no statistically significant association between microscopic lesions, gross pathology and contaminant body burdens. Collectively, contaminant body burdens were generally negatively correlated with functional immune responses including bactericidal, cytotoxic-cell and respiratory burst activity in both species. Exceptions were positive correlations of HCB and heptachlor epoxide with respiratory burst activity in largemouth bass, and HCB with respiratory burst activity in bullhead and ΣBHC for all three functional assays in bullhead. Data here provide additional support that organochlorine contamination is associated with immunomodulation, and that species differences exist within sites.