NIAGARA RIVER TOXICS MANAGEMENT PLAN
PROGRESS REPORT: PART II
REPORT ON NIAGARA RIVER CONDITIONS IN RELATION TO ACTIONS REPORTED IN PART I
A. POlNT SOURCES
CANADIAN POlNT SOURCE DISCHARGES
Under an enhanced monitoring program, focused on the NRTMP, the Ontario Ministry of Environment and Energy (MOEE) conducted monitoring with varying frequencies, from yearly to monthly, between 1986 and 1995. Consistent results were found, even when sampling was done monthly in 1991, showing that there were no seasonal variations.
In 1995, the point source program sampled six municipal sources and nine industrial sources. The sampling results from the 15 Ontario point sources indicate significant reductions in the daily loadings of the 18 priority toxics since 1986. In the past few years of monitoring, effluent quality has met Provincial Water Quality objectives. That means that end-of-pipe concentrations are acceptable against the objectives Ontario has set for all surface waters in the province. The total daily loading for the 18 priority toxic chemicals for 1995 was 0.0008 kg per day (0.002 lb/d), a reduction of 99% from 1986 to 1995 as shown in Figure 1. There were no detections of the 18 priority toxics at four facilities at the detection limits used for point source monitoring. Two of the 18 priority toxics were detected in 1995: arsenic and lead.
Lead remained the major component of the priority toxics loadings. The concentrations at which lead was detected imply that this compound was being discharged at background concentrations. Arsenic was detected at trace concentrations in effluent. While trace results confirm the presence of a contaminant, these results are approaching such low concentrations that they cannot be reliably quantified. There were no detections of the 10 chemicals targeted for a 50% reduction from any of the fifteen facilities sampled in 1995.
U.S. POlNT SOURCE DISCHARGES
In 1981-82, NYSDEC measured a total daily loading of 1240 kg/day (2740 lb/day) of organic and inorganic USEPA priority pollutants from the most significant industrial and municipal point sources. By 1985-86 this had dropped to 240 kg/day (540 lb/day). The most recent sampling conducted during 1993-94 indicated that the total was 190 kg/day (410 lb/day). NYSDEC requires point sources to sample and analyze their own effluent and report the results each month. During 1993-94, the self-monitoring results compared favorably to the NYSDEC data. During 1993-94 monthly permit parameter limits were exceeded less than one-half of one percent of the time. While most exceedances were minor, temporary deviations from requirements, the few that were important in magnitude or time triggered follow-up actions by NYSDEC and the facility.
Factors that contributed to the reductions from the early 1980s and the maintenance of the reduction are several including:
In summary, State Pollutant Discharge Elimination System (SPDES) permit requirements have required dischargers to construct wastewater treatment facilities, modify and improve industrial processes to increase treatment efficiencies, and develop pretreatment programs to reduce contaminant loadings to municipal wastewater treatment plants. All of these actions have resulted in reductions in the input of toxics.
FALLS STREET TUNNEL
Over the last 10 years, the U.S. has taken various measures to reduce the pollutant flow from the Falls street Tunnel:
Figure 2 shows dry weather flows from the Falls street Tunnel for 3 years between May 1988 and May 1991, as sampled once a month by the city of Niagara Falls. The flows were consistently above 13 million gallons a day in 1988. These were generally reduced to below 3 million gallons a day in 1991, with some exceptions. The flows were used to estimate loadings of organic chemicals and metals shown in Figure 3. Figure 3 shows that the actions taken to reduce dry weather flows from the Tunnel to the River were reducing the loads of toxic chemicals going into the River.
Since October 1993, the city of Niagara Falls has reported all overflows as recorded by automatic flow meters at the Falls street Tunnel and has certified that no dry weather flows directly to the Niagara River are occurring. Therefore, dry weather loadings of toxic chemicals from the Falls street Tunnel to the River have been reduced to zero.
Wet Weather Flow . Because combined sewer overflows (CSOs) continue to flow into the Falls Street Tunnel at 10 locations, the Tunnel continues to discharge to the Niagara River during wet weather events. The water from the CSOS combines with the groundwater that has seeped into the tunnel. This flow is pumped to the treatment plant until the plant's capacity is reached, at which time it overflows. A record was kept of all the overflows that occurred for a year from October 1993 to September 1994. There were 52 days of overflows, averaging 2.9 million gallons each.
There are pollutant data available for one overflow day in May 1994. Although one data set is not sufficient to draw conclusions, a high load might sound an alarm. However, the calculated loadings were low: 3 kg/day (6.5 lb/day) for total organic pollutants and 7 kg/ day (15.5 lb/day) for metals. Of the 13 out of 18 priority toxic chemicals that the city is required to sample for, none was detectable except for mercury and tetrachloroethylene.
B. NON-POINT SOURCES
In the Niagara River Toxics Study (1981-84), five municipal landfills were identified as having the potential to contribute contaminants to the River. Studies conducted by MOEE in 1991 and 1993 showed that the landfills had minimal impact on the River.
U.S. HAZARDOUS WASTE SITES
Given the limited information available about non-point sources, the U.S. has proceeded with its actions based on the assumptions that hazardous waste sites and contaminated sediments are the most significant non-point sources of toxic chemicals to the River. NYSDEC and USEPA identified 26 waste sites believed to have the greatest potential for toxic pollutant loadings into the Niagara River, and put them on accelerated remediation schedules. They have been tracking the progress of remedial activities in semi-annual reports [83-89]. The U.S. agencies have made the assumption that when the remediation systems are in place, the groundwater flows carrying contaminated loads from those sites to the River cease. At some sites, a partial reduction was estimated based on partial remediation cutting off a fraction of groundwater movement from the site. Based on these assumptions, USEPA has estimated a 25% reduction in loads to date, and predict an 80% reduction by the end of 1997, with a 99% reduction by the year 2000. NYSDEC estimates that reductions to date are probably higher. Work by USEPA and NYSDEC is underway to improve reduction estimates. As remediation systems come on line, the assumptions need to be substantiated by monitoring results.
Monitoring at U.S. waste sites is conducted by NYSDEC, USEPA, or the owner industries under the Superfund or Resource Conservation and Recovery Act (RCRA) laws. since most of the remedial actions at these waste sites are containment remedies, the agencies rely on measurements of groundwater movement at monitoring wells to determine whether contaminated groundwater is still traveling off the site or whether it is being drawn onto the site where it will be treated and discharged to waste water treatment plants. The groundwater is routinely analyzed for its chemical constituents.
Reduction in the off-site flow of groundwater contaminants has been achieved for the following sites, and is either confirmed in the listed monitoring reports, or is expected to be confirmed as noted:
Occidental Hyde Park. Most remediation is in place for both the soil and underlying bedrock, and is expected to be completely operational by March 1997. Retention of contaminants onsite has been documented by data from monitoring wells, most of which have operated successfully. The data are presented in quarterly bedrock monitoring reports and quarterly overburden monitoring reports, which are available at the USEPA Niagara Falls Public Information Office along with special reports on recent activities. The monitoring system has been redesigned to provide more certainty on the success of the remediation.
DuPont Necco Park. Physical barrier walls and on-site pumping wells have reduced contaminated flow from the southern boundary of the site, and load reductions have been estimated to be between 27% and 55%. The monitoring results are presented in the following reports available at the USEPA Public Information office in Niagara Falls, New York:
Interpretive Report for Necco Park
Occidental, S-Area. A barrier wall has been built along the River's edge to contain contaminants in the soil, and pumping systems came on line in August 1996 to contain and treat contaminated water from bedrock and overburden on the site. Hydraulic monitoring will now be implemented to test the systems' effectiveness. As yet, there are not enough data to confirm whether the loadings to the River have been completely contained. Fact sheets on all recent activities may be obtained at USEPA's Public Information office. An annual report providing more documentation is due to USEPA in March 1997.
Occidental Chemical-Buffalo Avenue. At this time, a majority of on-site corrective measures are in place and operational. Additional corrective measures are in design or construction. Corrective measures include the construction of an overburden barrier wall in 1994 that restricts the direct discharge of contaminated groundwater from the southern boundary of the plant to the Niagara River. An overburden groundwater collection system is currently under construction upgradient of the barrier wall. An 800 gpm bedrock groundwater pump and treat program was installed in 1996. The system recovers approximately 100 lbs/day of organic contaminants from the groundwater. Preliminary effectiveness monitoring data shows that a hydraulic barrier has been established throughout most of the northwestern and north central property boundary. The system is still undergoing optimization and additional enhancements will be made to improve hydraulic containment. Contaminated soils have been removed and capped, including the physical separation and removal of 36 tons of liquid mercury from site soils and capping of dioxin-contaminated soils at several areas.
CECOS International. At this site a groundwater recovery system has been pumping contaminated groundwater since 1990. Currently, 20 recovery wells collect contaminated groundwater which is treated on site and discharged to the city of Niagara Falls Wastewater Treatment Plant. From 1991 through 1995 over 37 million gallons of groundwater have been treated resulting in the removal of nearly 900 kg (2,000 lbs) of organic compounds. In addition, approximately 18,000 m3 (24,000 yd3) of soils contaminated with PCBs, organic compounds and metals have been removed for off-site disposal. A low permeability ground cover has been constructed over this area to minimize infiltration of precipitation
The interim groundwater pump and treat has been successful in containing and remediating the groundwater contamination at the facility. This has been confirmed by wells monitoring the hydraulic gradient and contaminant levels. Future plans include expansion of the groundwater capture zone by optimizing pumping rates, operation of a groundwater collection drain, and installation of additional recovery wells in order to facilitate a more rapid clean-up of the site.
DuPont - Buffalo Avenue. As of January 1992, all remedial systems at this site were completed and operating. Remedial measures consist of groundwater pump and treatment of both bedrock and overburden groundwater. From 1992 through 1995 over 11,000 kg (24,000 lbs) of organic contaminants have been removed from the on-site pumping well and an additional 5,700 kg (12,500 lbs) of organic contaminants from the off-site well capturing groundwater from the site.
In addition to well monitoring, biomonitoring can be used to make sure that contaminated groundwater is not flowing from the sites to the River after remediation (see section "D. Biomonitoring" below).
Occidental-Durez, Niagara Falls. A bedrock groundwater recovery system has been operating since 1989, removing groundwater contaminated with phenols and other organics. From 1989 through July 1996, over 6,800 kg (15,000 lbs) of phenol have been removed from the three onsite pumping wells. An overburden groundwater collection drain has been operating since 1993 and has recovered approximately 160 kg (360 lbs) of phenol. Performance monitoring reported by occidental includes the operating status of the recovery systems, hydraulic monitoring, and groundwater quality monitoring.
Bell Aerospace. Five groundwater extraction wells have been operating since April 1993 as part of the off-site groundwater remedial program. Historical groundwater monitoring data from the facility indicate that the extent of the off-site plume of groundwater contamination has been shrinking as a direct result of the groundwater remedial program that Bell has implemented.
C. UPSTREAM/DOWNSTREAM PROGRAM
Since 1986, Environment Canada has operated water quality sampling stations at the head [Fort Erie (FE)] and mouth [Niagara-on-the-Lake (NOTL)] of the Niagara River under what has become known as the Upstream/Downstream Program. This program has measured, on a weekly basis, the changes in the concentrations of over 70 chemicals in the water entering and leaving the Niagara 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. The resultant data base is one of the best in the Great Lakes.
The Four Parties have adopted three priorities for considering which chemicals to measure and report on: (1) exceedences of standards, objectives, criteria; (2) chemicals which do not necessarily exceed these, but nonetheless are useful for demonstrating progress; and (3) chemical "markers" that identify pollution from a specific source. Furthermore, the Four Parties are interpreting the monitoring data to link the results of control measures or remedial activities to the data collected in ambient and source monitoring programs.
Looking at the Upstream/Downstream program data in this way provides important information on the nature of the inputs and the progress made in controlling them over the last 10 years. Several examples drawn from previous work by Environment Canada [1995 (SOLEC poster) and 1996 (IAGL poster) updates to reference 91] are useful in demonstrating progress. The toxic chemicals shown in these examples tend to cling preferentially to particles in the water, so the suspended sediment data provide a good picture of what is happening in the River,
The data in the figures show clearly whether the inputs of toxic chemicals are continuous or whether they occur randomly. "Spikes" in the data probably represent fairly large short-term inputs of chemicals from sources along the River. Decreases in overall concentrations and decreases in both the occurrence and magnitude of the "spikes" are important indicators of the progress in controlling sources. In addition, by comparing upstream data from FE with downstream data from NOTL, it is possible to see whether the chemicals come predominantly from Lake Erie or from sources along the River (e.g., see Figures 6a and 6b, described below). After taking into consideration the many "natural" factors that might be involved, such as weather or the amount of suspended sediment in the water, some conclusions can be drawn about the impact and effectiveness of remedial measures taken at Niagara River sources.
Figures 4 and 5 show the suspended sediment concentrations of octachlorostyrene (OCS) and hexachlorobutadiene (HCBD), respectively, at NOTL. Neither of these chemicals is detected at FE, suggesting the major sources are from places along the Niagara River rather than Lake Erie. Furthermore, although HCBD is not one of the 18 priority chemicals, it is a good indicator of progress. Both chemicals show a reduction in concentrations. OCS is detected less frequently after 1993. Similarly, both chemicals show a reduction in both the number and magnitude of the "spikes". These observations suggest a reduction of inputs to the River and better control of sources. Starting in 1993, however, the concentration of the HCBD "spikes" start to increase, although the levels are still less than those observed over the period 1986-1990. Similar recent increases in inputs have been seen for other chemicals as described below. The reasons for these increases are being investigated.
Figures 6a and 6b show the suspended sediment data for hexachlorobenzene (HCB) at FE and NOTL. The much higher concentrations observed at NOTL indicate that there are significant sources of HCB along the Niagara River. The NOTL data show much the same pattern as discussed above for HCBD. Between 1986 and 1992, there is a reduction in overall concentrations as well as the number and magnitude of the "spikes". This again suggests better control of sources. In 1993, however, the "spike" concentrations increase, similar to the observations for HCBD.
Figure 7 shows the suspended sediment concentration data for mirex at NOTL. Mirex is only found at NOTL, suggesting the sources are along the Niagara River. In contrast to OCS, HCBD and HCB, the mirex data suggest intermittent inputs, caused by episodes. The data show that, with the exception of 1991, the concentrations and frequency of detection of mirex appear to have decreased suggesting better control of sources. However, starting in 1994, mirex is again detected more frequently, the inputs having changed from being episodic to being continuous, similar to the patterns observed in 1986 and 1987. This appears to coincide with the increases in "spike" concentrations noted above for some of the other chemicals. The reasons for this are being investigated.
Figures 8a and 8b show the upstream and downstream concentrations of dieldrin dissolved in water rather than attached to suspended solids. These data show that Lake Erie is the major contributor of dieldrin to the River and that, if there are inputs along the River, they are small in comparison. Success in controlling inputs of this pesticide to Lake Ontario from the Niagara River will be dependent on the success in dealing with sources upstream of the Niagara Riverbed The data also suggest that concentrations in Lake Erie have been decreasing since 1986 and this is also reflected in the NOTL data.
Preliminary statistical analysis has been carried out by EC on the 18 priority toxic chemicals by comparing 1994 data with those for 1986. The initial results show that, with the exception of a few chemicals in the suspended sediment phase, most of the chemicals have undergone a considerable reduction in concentration since 1986.
Aquatic organisms can concentrate many chemicals in their tissues and reveal the presence of contaminants that cannot be directly detected in water, because of dilution.
Since 1981, MOEE has monitored, every other year, contaminants in caged mussels at sites along the Niagara River. The cooperative assistance of the NYSDEC has enabled MOEE to deploy mussels on the U.S. and Canadian sides of the River. The mussel biomonitoring program has been successful at identifying contaminant sources by providing information on the presence or absence of contaminants in the tissue of deployed mussels.
Both the MOEE and NYSDEC have collected and analyzed indigenous, young-of-the-year fish from locations along the shoreline of the Niagara River. The MOEE has collected fish from both Canadian and U.S. locations at least every other year since 1975. NYSDEC has collected fish from locations on the U.S. side of the River annually between 1984 and 1987, and again in 1992.
The following examples, extracted from preliminary MOEE data, are useful in demonstrating progress of remedial measures.
Bloody Run Creek and the nearby seeps which run down the face of the Niagara Gorge were historically contaminated from the Hyde Park hazardous waste site. Prior to remediation, the drainage from this site was a major source of dioxin contamination to the Niagara River. Remediation construction at this hazardous waste site is nearly complete. Figures 9a and 9b show the dioxin and furan concentrations, respectively, for the period 1993 to 1995. Concentrations for the last two years were considerably lower than those reported in 1993. Preliminary examination of these data suggest that recent sediment removal actions along Bloody Run Creek and action to cover and contain contaminated sediment and soil at the mouth of Bloody Run Creek and on the shoreline of the Niagara River in the vicinity of the creek may have reduced the bioavailability of these contaminants to aquatic life in this area. This site will continue to be monitored in future surveys to ensure that contaminants no longer enter the River.
Figure 10 shows the concentrations of some chlorobenzenes in mussels placed adjacent to Pettit Flume at the Durez waste site in Tonawanda. The preliminary data suggest that, although still present, the concentrations of chlorobenzenes typically found in mussels at the Pettit Flume were considerably lower in 1995 than concentrations found in previous years suggesting the positive effects of remedial actions.
Young-of-the-year fish, principally spottail shiners, have limited home ranges near shore and are of known age, making them useful indicators of local, recent chemical inputs to the aquatic ecosystem. These examples are taken from MOEE reports.
Figure 11 shows the concentrations of PCBs in spottail shiners near the head of the Niagara River (Fort Erie [FE]) and at the mouth (Niagara-on-the-Lake[NOTL]). For those years in which there are data for both sites, the concentrations at the mouth of the Niagara River are higher than those coming from Lake Erie, indicating sources along the River. This is consistent with the Upstream/Downstream data. The NOTL data indicate that PCB concentrations in spottail shiners have decreased substantially since the 1970s; however, they appear to have remained at about the same level since the latter half of the 1980s.
Figures 12 and 13 show PCB concentrations in spottail shiners collected in the vicinity of specific hazardous waste sites. These sites include the Durez site at Pettit Flume (Figure 12), the Love Canal site near Cayuga Creek and Occidental Chemical 102nd street site (Figure 13). A comparison of Figures 12 and 13 with Figure 11 shows that PCB concentrations in fish collected near waste sites are higher than those in fish not near a direct source. All these examples underscore the value of using biomonitors to track inputs from individual sources.
A significant reduction in PCBs over time has occurred at the Cayuga Creek location, suggesting the effectiveness of soil and sediment removal in 1989 at its two tributaries: Bergholz and Black Creeks. These creeks had been contaminated from storm drain discharges from the Love Canal waste site. NYSDEC and MOEE have also analyzed for the presence of dioxin in Cayuga Creek fish over time and have found post-remediation decreases, although concentrations are not yet at levels below criteria.
E. SEDIMENT CORING
In the fall of 1995, NYSDEC and USEPA joined forces with Environment Canada to collect sediment core samples from the depositional area at the mouth of the Niagara River. Cores from this depositional area tell the history of toxic chemical loadings to Lake Ontario from the River, because many toxic pollutants (e.g., pesticides, PCBs) are principally conveyed through waterways attached to suspended sediments. Every few centimeters along the length of the core were analyzed separately to determine the concentrations of toxic chemicals on deposits from the particular time frame represented by that the segment. The results presented below are taken from a NYSDEC report to be published in winter 1996.
The preliminary results for PCBs, Mirex, octachlorostyrene, Dioxin (2,3,7,8-TCDD), and Hexachloro-benzene are shown in Figures 14 through 17. The depth from the surface is shown on the left of the graph and the approximate time frame, as determined by radioisotope dating, is shown on the right. These data indicate that the burden of toxic chemicals associated with suspended sediment coming from the River have declined, most dramatically between 1960 and 1980. The results were similar for all priority toxic chemicals.
The graphs also show a line entitled "Persaud's LEL (Lowest Effect Level)", formally known as the MOEE Provincial Sediment Quality Guideline LEL . This is the level at which a contaminant can be expected to begin to affect aquatic organisms, as determined through field studies by MOEE. This set of guidelines is the most complete, and in most cases the most rigorous, for toxic chemicals in sediment. The surface concentrations of all priority chemicals in these core samples of Niagara River delta sediment are now less than these levels.
In summary, several sets of data appear to show that actions taken under the Niagara River Declaration of Intent have resulted in substantial reductions of toxic chemical pollutants in the Niagara River. Significant actions are listed in Part I of this progress report and include: