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REPORT

PHASE II MOIRA RIVER STUDY
IMPACTS OF THE FORMER DELORO MINE SITE
ON THE MOIRA RIVER SYSTEM

January 2001

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INTRODUCTION

1.1 Background

The Moira River is located in southern Ontario and flows from the Canadian Shield south across the St. Lawrence lowlands to Belleville and the Bay of Quinte on Lake Ontario. The Deloro Mine Site is located on this river about 45 kilometres north of Belleville, Ontario (Figure 1.1-1). Gold mining started in the late 1860s. By the early 1900s, the gold mines had closed and the Deloro Mine Site was used to process silver and cobalt ores from other mines in northern Ontario. From the 1930s to the 1950s, smelted ore was brought from Eldorado Nuclear Limited in Port Hope for further refinement to extract cobalt. The Deloro Mine Site was the first plant in the world to produce cobalt commercially and was also a leading producer of stellite, a cobaltchromium-tungsten alloy highly valued during the war years. Ores from all over the world were processed in Deloro's smelters. Pesticides were produced from the arsenic by-products of the smelting operations and manufactured as a major activity at the Deloro Mine Site until those products were replaced by organic pesticides in the late 1950s.

By the time all operations ceased, a wide variety of waste materials containing arsenic and a variety of other metals had accumulated and affected the quality of water and soils on the Deloro Mine Site, as well as quality of water and sediment in the Moira River system. When the last owners abandoned the property in 1979, the Ministry of the Environment (MOE) assumed responsibility for the environmental management of the Deloro Mine Site as 'remediator of last resort'.

Since then, the ministry has made significant reductions in the contribution of metals to the Moira River system through a number of remedial actions. Eight hectares of tailings were covered, unsafe buildings demolished and mine shafts were located and sealed. The ministry also built and continues to pay for the operation of a treatment plant that removes arsenic and other heavy metals from the groundwater on the Deloro Mine Site. As a result of these actions, the ministry has reported that loadings of arsenic to the Moira River have been reduced by more than 80 per cent. The ministry's consultants are currently working on a plan for the final cleanup of the Deloro Mine Site, to control and securely contain all types of contamination at the Deloro Mine Site - from arsenic to radioactivity. The proposed interim Provincial Water Quality Objective (PWQO) for arsenic of 5 µg/L (micrograms per litre) will be one of the cleanup objectives. The ministry proposes to meet this interim PWQO on average, at the Highway 7 site boundary. This is significantly more stringent than the current PWQO of 100 µg/L for arsenic.

THE MORA RIVER WATERSHED

REFERENCE
PROVINCE INSET MAP TAKEN FROM ESRI CDS FROM THE ARCVIEW SOFTWARE BASE MAP PROVIDED BY GIS GOLDER MISSISSAUGA

SCHEMATIC ONLY NOT TO SCALE

The ministry also conducted a comprehensive Environmental Health Risk Study in the Village of Deloro. This study, released in July 1999, showed that the levels of arsenic and other metals present in the Village of Deloro are safe.

The Moira River Study was commissioned by the Ministry of the Environment (MOE) in 1999 to determine the extent of effects from the Deloro Mine Site on the Moira River and to predict the environmental response to the final cleanup of the site. The MOE established a Steering Committee to direct and oversee this Study. This committee included technical staff from the MOE and representation from the Ministry of Natural Resources, Quinte Conservation Association and the Hastings and Prince Edward Counties Health Unit. Phase I of the Moira River Study, carried out by Water Systems Analysts (W B. Kilgour), C. Portt and Associates and Dr. D.G. Dixon (University of Waterloo), was completed in February 1999. Phase I involved the review of existing studies of the Moira River watershed. Information gaps were identified and a detailed study design was developed for Phase II: a comprehensive assessment of the aquatic environmental effects on the Moira River below the Deloro Mine Site downstream to Belleville. The Steering Committee and the Moira Lake Property Owners' Association provided input to the study design.

Golder Associates Ltd. (Golder), in association with GlobalTox International Consultants Inc. (GlobalTox) was retained in April 1999 to implement Phase II of The Moira River Study.Phase II included a comprehensive assessment by Golder of the aquatic effects in the Moira River system attributable to the mining, mineral processing and refining activities conducted at the Deloro Mine Site. Aquatic life in the Moira River system has been exposed for more than 100 years to a variety of effluents from the Deloro Mine Site. This study presented a unique opportunity to examine the long-term aquatic effects associated with metal mining, processingand refining activities.

Phase II of The Moira River Study also included a preliminary quantitative risk assessment (PQRA) to determine if the observed metal concentrations could pose a potential health risk to the residents and recreational users of the watershed. GlobalTox conducted this component of the study.

The third component of Phase II of the Moira River Study was predictive water and sediment quality modelling conducted by Golder to assess the effects of the final cleanup of the Deloro Mine Site. The final cleanup plan for the Deloro Mine Site is currently being developed by the ministry.

The Moira River Study Steering Committee reviewed the draft Phase II report of this study. The draft has also been "peer reviewed" by a panel of international experts in the fields of biology, chemistry, toxicology, radioactivity, environmental modelling and risk assessment. The report was finalized to address comments from the Steering Committee, the peer reviewers and comments received from the public during the public consultation period that ended on September 26, 2000.

This introductory section addresses the context of this study, the site setting, the study objectives, the study program, discussion of applicable guidelines and reference site selection.

1.2 Study Context

One hundred years of mining, mineral processing and refining operations at the Deloro Mine Site have generated a wide variety and significant quantity of waste materials abandoned around the site. A detailed discussion of the history of the Deloro Mine Site and the extensive investigations and mitigative measures implemented are beyond the scope of this report.

A number of studies have been conducted downstream of the Deloro Mine Site to assess the presence of mine-derived metals. The findings from these studies have been considered where appropriate. These studies have included:

• Surface water quality survey that included nutrients and metals analyses (OWRC1960);
• Biological survey (Owen and Galloway 1969); and
• Aquatic sediments (Mudroch and Capobianco 1980; Cornett and Chant 1986; Cornett et al 1987; Azcue and Nriagu 1993).

These studies have focussed on arsenic, metals and radionuclides in water and sediment, and to a lesser extent, in biota. These studies have shown elevated concentrations, principally arsenic, are present in the water and sediment. The ecological significance of these occurrences has not been addressed in detail since an initial study conducted in 1969 (Owen and Galloway 1969).

Beginning in 1964, an extensive water quality database has been compiled by the MOE from monthly water quality sampling conducted at as many as 23 stations within the Moira River system. This program was conducted as part of the Provincial Water Quality Monitoring Network under the direction of the MOE's Environmental Monitoring and Reporting Branch. Since 1993, this database has been augmented with the results of weekly water quality sampling conducted at 8 stations on and in the vicinity of the Deloro Mine Site. This sampling was conducted by the Ontario Clean Water Agency (OCWA), the operators of the onsite treatment plant.

A number of monitoring programs are being conducted in the watershed. While not necessarily specific to the Deloro Mine Site, these programs have also provided useful data that have been incorporated into this study where appropriate. These are:

• MOE Provincial Water Quality Monitoring Network Program; and
• MOE/MNR Sport Fish Contaminant Monitoring Program.

1.3 Study Setting

The Moira River Watershed

The Moira River watershed lies north of the Bay of Quinte. It is irregular in shape and is approximately 56 miles (90 kilometres) long by a maximum of 32 miles (51.5 kilometres) wide. It occupies an area of approximately 1,056 square miles (2,735 square kilometres) and is bounded by the Trent River, Mississippi River and Salmon River watersheds (Barrens 1960). Both Moira and Stoco lakes lie on the main channel of the Moira River. The principal tributaries, the Black and Skootamatta rivers, join the Moira River from the north between these two lakes (Figure 1.1-1). The headwaters of the Moira River, as well as the entire Black and Skootamatta River watersheds, are located on the Precambrian rock of the Canadian Shield. As the Moira River flows southward through the lakes and beyond, it passes over the mostly thin glacial clay and till deposits and limestone outcrops of the Napanee Plain before emptying into the Bay of Quinte at Belleville (Ostray and Singer, 1981). Average monthly flows in the Moira River at Highway 7 vary from 14.3 m³/sec to a low of 0.3 m³/sec with a mean annual flow of 3.8 m³/sec. Average monthly water flows in the Moira River and its two main tributaries, the Black and Skootamatta rivers, are shown in Figure 1.3-1.

Figure 1.3-1
Average Monthly Flows in the Moira, Black and Skootamatta Rivers (1965 to 1999)

The headwaters of the Moira River and the entire flow of the Black and Skootamatta rivers are "tea-stained" by natural decomposition of vegetation. This is typical of watercourses on the Canadian shield.

The river's form and substrate composition are affected considerably by the local geology. On the Canadian Shield, these rivers flow through occasional sluggish beaver ponds and tumble over bare rock outcrops and through bedrock chutes. Substrates range from fine organic material in slack water areas such as beaver ponds, to bare bedrock chutes with varying amounts of sand to boulder-sized particles weathered out of the outcrops. Habitats in these sections of the rivers are relatively unproductive. Fish and invertebrate populations are small and form communities of relatively low species diversity.

Beginning north of the Deloro Mine Site near Malone and continuing downstream towards Bend Bay, the Moira River encounters patchy till deposits overlying the bedrock. Here the river flows over occasional shallow rocky riffles characterized by relatively abundant and diverse fish and invertebrate communities. Substrates are rocky and sandy, with bare bedrock outcrops and limited areas of deposition of fine grained sediments consisting of silt and organic material.

Above Bend Bay, the river leaves the shield and begins to flow over glacial till deposits. Here the river is wider and flow is sluggish. Moira and Stoco lakes lie on this section of the river. These lakes are small relatively narrow and deep and have acted as traps for the accumulation of sediment. Both Moira and Stoco lakes have highly productive plankton and aquatic plant-based food webs that support diverse fish communities.

Downstream of Stoco Lake, the Moira River continues south across the Napanee Plain through small mill communities like Roslin and Latta and through Belleville. Substrates are generally rocky, owing to the thinly covered limestone of the Napanee Plain. Depositional areas are limited, usually occurring in the small headponds located above the mill dams. The Moira River is wide and shallow with rocky substrates as it discharges into the Bay of Quinte.

Land Use

Land use within the Moira River watershed is primarily mixed agriculture with recreational activities focussed around Moira and Stoco lakes and downstream on the Moira River. Historically, small-scale mining activities were conducted in the area beginning in about 1866. By 1871, seven mines were being worked in the Moira River watershed (CHRML 1987). Operations at these mines ceased early in the 1900s.

In the north end of the watershed, small communities such as Malone and Deloro are located among the farms and scattered cottages. There are few residents located along this section of the Moira River and opportunities for recreation are limited by the rocky nature of the river substrate.

Agricultural practices on the mostly thin soils and rocky outcrops of the watershed comprise primarily forage crops and mixed livestock, with extensive areas of unimproved lands.

Highway 7 traverses the area in an east west direction and is located generally in the vicinity of the southern limit of the Canadian Shield. Highway 7 crosses the Moira River immediately south of the Deloro Mine Site and just above the junction of Young's Creek with the Moira River.

Farther down the river are the larger towns of Madoc and Tweed located along the route of Highway 7 and associated with Moira and Stoco lakes, respectively. Cottages, campgrounds and parks encircle each of Moira and Stoco lakes and provide access to a variety of recreational activities for local residents and visitors; including swimming, fishing, boating and watersports in the summer and ice fishing, cross country skiing and snowmobiling in the winter. It is estimated that there are about 624 residences between the Deloro Mine Site and the outlet of Stoco Lake, of which about half are cottages. Highways 37 and 62 traverse this area connecting Highway 7 to Highway 401 that crosses the Moira River near Belleville to the south.

Downstream of Stoco Lake small communities like Roslin and Latta are located at mill sites and existing dams on the Moira River. The City of Belleville is located south of Highway 401 at the mouth of the Moira River. Industry is limited within the watershed and most of it is concentrated within and around Belleville and the major transportation route of Highway 401.

1.4 Study Objectives

The objective of the aquatic environmental effects study (AEES) of Moira River was to characterize the extent and significance of aquatic environmental effects downstream from the former Deloro Mine Site. The study design was developed to clearly determine the extent and 'ecological significance' of metal concentrations in the Moira River system by addressing the following questions:

1. Are metals entering the Moira River system?
2. Is there a measurable biological response in aquatic invertebrates and fish?
3. Are the metals in the system causing the biological response observed in invertebrates and fish?
4. Do the metal concentrations present in water and sediment of the Moira River system pose a risk to human health?
5. What amount of cleanup would be necessary at the Deloro Mine Site to meet Provincial Water Quality Objectives in the Moira River and to reduce sediment concentrations to below concentrations associated with biological effects?

The following task-specific objectives addressed the three sections of the Moira River Study:
(1) AEES; (2) human health risk assessment; and, (3) predictive water quality model.

I. AEES Objectives

The objectives specific to the AEES were as follows:

• Obtain water and sediment quality data from representative stations in the Moira River system and appropriate reference locations and evaluate for temporal and spatial trends including historical water quality trends;
• Obtain benthic invertebrate community data from the Moira River system and reference locations and evaluate for relationships with metal concentrations; and
• Obtain data for two sentinel fish species and evaluate the population-level and whole organism responses for possible relationships with metal concentrations.

II. Human Health Risk Assessment

This consisted of a Preliminary Quantitative Risk Assessment (PQRA), the objective of which was to determine if the metals released to the Moira River system pose a potential health risk to people in the Moira River watershed.

III. Predictive Water Quality Model

The objective of the modelling component was to develop and implement a decision support model to predict sediment and water quality in Moira and Stoco lakes for selected metals. The model predicted the water and sediment quality resulting from various levels of future cleanup activities to be conducted at the Deloro Mine Site, and the time period that would be required to achieve sediment and water quality guidelines or objectives at downstream locations.

1.5 Study Program

A study program had previously been developed by WSA (1999) as Phase I of the MOE's Moira River Study. Some minor modifications were made to this study design on the basis of a detailed review conducted by Golder and experience gained during an initial site reconnaissance. These refinements were as follows:

1. Sediment toxicity testing was conducted at the same stations where benthic invertebrates are collected (including reference locations). The toxicity data would then coincide more closely with the benthic invertebrate community data, completing the Sediment Quality Triad. A subset of stations representing a broad range of metal concentrations were selected for toxicity testing and a broad range of metal concentrations was tested.
2. Sediments were tested within six weeks of collection.
3. Seasonal cycles were examined for water quality.
4. Metals in longnose dace were measured instead of benthic invertebrates because of insufficient invertebrate abundance.
5. For benthic invertebrates, a series of locations along a reference river were examined to assess changes with increasing distance downstream.
6. For fish studies, longnose dace were sampled in the fall rather than the spring.

In summary, the following activities were completed for the Phase II component of the Moira River Study:

• Selection of reference and exposed sites;
• Spring survey for longnose dace;
• Spring collection of sediments for chemistry (66 grab sample sites), laboratory toxicity testing (at 27 of the 66 grab sample sites) and benthic invertebrate sampling (at 36 of the 66 grab sample sites);
• Summer survey of lake water temperatures and dissolved oxygen profiles in Round, Consecon, Moira and Stoco lakes;
• Mail/hand out water use questionnaire;
• August sediment core sampling (11 sample sites);
• Fall sampling program for sentinel fish species (119 of 257 longnose dace and 123 of 207 white sucker processed for effects parameters);
• Preliminary quantitative risk assessment;
• Predictive water quality modelling;
• Data compilation, interpretation and analysis; and
• Reporting.

The study area consisted of almost the entire Moira River system from upstream of the Deloro Mine Site to Belleville at the Bay of Quinte. Reference sites located within the watershed included the Moira River upstream of Malone, and the Black and Skootamatta rivers. Reference sites located outside of the watershed include the Salmon River, and Round and Consecon lakes.

The environmental components of the study included water quality, sediment quality, benthic invertebrate communities and fish communities. Each component is detailed in subsequent chapters of this report.

This project is limited to the spring, summer and fall of 1999 and the winter of 1999/2000, with the majority of the field work occurring in the spring and fall of 1999.

1.6 Discussion of Applicable Guidelines

Water quality data used in the AEES have been compared to the Provincial Water Quality Objectives (PWQO) (MOE 1999a). The PWQOs were developed to be protective of aquatic life, but are not direct measurements of aquatic ecosystem health. The PWQOs include objectives for uranium and radium-226, two of the radionuclides measured in this study. Where objective values are not being met, all practical measures are to be taken to improve water quality (MOE 1999a). As is discussed in Section 2.1, water quality data were screened for metals that exceeded PWQOs to identify the metals of concern for the aquatic environmental study. If a PWQO was not available for a particular metal or radionuclide, concentrations were compared to reference concentrations at reference sites.

The ministry has stated that the interim PWQO for arsenic is to be adopted as one of the objectives of the final cleanup plan to be developed for the Deloro Mine Site. The interim PWQO for arsenic is 5 µg/L, which is much more stringent than the current PWQO of 100 µg/L. The interim PWQO for arsenic was considered only in the section of this report addressing the predicted response to the aquatic system to future cleanup actions (Section 4). Elsewhere, current PWQOs have been used to examine the water quality data.

Sediment quality data used in the AEES were compared to the Provincial Sediment Quality Guidelines (PSQGs) (MOE 1993). The PSQGs were developed for the protection of aquatic life and contain a set of guideline concentrations in sediment, expressed as lowest and severe effects levels (LELs and SELs). These concentrations, or effects levels, are not a direct measure of the health of an aquatic system. Exceedances of LELs or SELs typically indicate the need to conduct biological testing of aquatic organisms (MOE 1993). Consistent with this requirement, the Moira River Study included the assessment of the aquatic environment including benthic invertebrates and fish species. Sediment guideline values have not been developed for some parameters (e.g., cobalt), in which case, the MOE have detailed the methodology by which site specific screening level concentrations (SLCs) are to be developed. SLCs were developed for two of the metals under consideration, as discussed in Section 2.2

Water quality data used in the PQRA were compared to Ontario Drinking Water Objectives (ODWO) (MOE 1999a) to identify metals of concern for human health. If an ODWO was not available for a particular metal, criteria from Table A (potable groundwater) of the MOE Cleanup Guideline were used (MOE 1999b). Both the ODWOs and Table A criteria represent safe concentrations for human health.

1.7 Reference Site Selection

The Moira River Study required the selection of reference rivers and lakes to compare with the Moira River and Moira and Stoco lakes. Information on lakes and rivers in the Moira River watershed and adjacent watersheds was obtained from the Kingston Ministry of the Environment (MOE), the Quinte, Cataraqui Region, Crowe Valley, Napanee Region, Lower Trent Region, and Mississippi Valley Conservation Authorities, as well as the Peterborough, Bancroft and Kingston offices of the Ministry of Natural Resources (MNR). Water Survey of Canada data records were reviewed for substrate, water quality and quantity information.

All reference river and lake sites were selected based on a review of background information and two site reconnaissance surveys undertaken on April 20 - 23, and 29 - 30, 1999. Information was obtained regarding water quality and quantity; however, limited data were available on the type and quality of aquatic habitat and on the fishery of the rivers that were being evaluated as potential reference sites. Information on lakes was more readily available and numerous lakes were considered as potential reference locations in discussions with MOE, MNR and Conservation Authority staff.

Based on a review of existing information, primary and secondary screening factors/criteria were established for reference site selection. Chemical and physical data of candidate lakes and rivers were compared to those of Moira Lake, Stoco Lake and Moira River. Primary screening factors established for lake reference site selection included basin and watershed geology, retention time, thermal stratification, oxygen depletion/profile, trophic status, maximum and mean depth, hardness, alkalinity and pH, shoreline development, fish community composition and potential metal sources. Secondary factors included the presence of alga blooms and aquatic vegetation, lake size and volume, drainage basin area, study area proximity and access.

River reference site selection incorporated the following primary screening factors: geology, gradient, habitat complexity/dominance, flow, velocity, hardness, alkalinity, pH, potential metal sources, average wetted stream width and depth. The secondary screening factors included drainage area, water colour, substrate, study area proximity and access and elevation.

Based on an evaluation of primary and secondary screening factors, Round Lake and Consecon Lake were considered most similar to Moira and Stoco lakes in terms of physical and chemical characteristics and were selected as the reference lakes. Benthic invertebrate, sediment toxicity and sediment chemistry samples were collected at the inlet, outlet and deep basin in each of the four lakes plus one additional mid-basin sample from Consecon Lake, to ensure that an oxygendepleted condition was represented.

The selection of river reference sites took into consideration that Moira River is physically different upstream and downstream of Bend Bay. A total of four (4) reference sites were selected to compare with the upstream section of Moira River (between the Deloro Mine Site and Bend Bay). One reference station was selected on each of the Black and Skootamatta rivers and two were selected on the Moira River upstream of the Deloro Mine Site near Malone. A total of three (3) reference sites were selected on the Salmon River to correspond with the downstream reach of Moira River (Figure 1.1-1). Benthic invertebrates, sediment toxicity and sediment chemistry were sampled at 7 reference river sites and at 8 exposed river sites.

1.8 Report Organization

The report is separated into chapters that cover the different components of the study. Chapter 2 details the aquatic environmental effects of the mine on the Moira River system, and has subsections discussing water quality (Section 2.1), sediment quality (Section 2.2), benthic invertebrate communities (Section 2.3), metals concentrations in fish tissue (Section 2.4), and fish sentinel species (Section 2.5). Chapter 3 discusses the preliminary quantitative risk assessment for human health. Chapter 4 details the predictive modelling of metal concentrations in the river system. Chapter 5 provides conclusions and recommendations. Most chapters have relevant appendices containing data and other backup information.

1.9 Acknowledgements

The assistance of the Ministry of the Environment and the Ministry of Labour in completing this study is gratefully acknowledged. This includes staff of the:

• Environmental Monitoring and Reporting Branch who most ably completed the collection of sport fish, benthic invertebrates and sediments, and assisted with sentinel fish;
• Laboratory Services Branch who conducted the analyses of metals;
• Ministry of Labour Radiation Protection Monitoring service staff who conducted the analyses of radionuclides; and
• Quinte Conservation Association who contributed in collecting the water quality monitoring program samples.

This study could not have been completed without the willing cooperation of these staff.

This report has benefited from the thorough review conducted by internationally recognized experts selected by the MOE as the peer reviewers for this Study. These experts were:

• Dr. Charles Abernathy, U.S. Environmental Protection Agency
• Dr. Gerald Ankley, U.S. Environmental Protection Agency
• Dr. Henry Caplan, University of Saskatchewan
• Dr. William Cullen, University of British Columbia
• Dr. Peter Hodson, Queen's University
• Dr. Alex McCorquodale, University of New Orleans
• Dr. Kelly Munkittrick, University of New Brunswick
• Dr. Chris X-Le, University of Alberta

1.10 References

Azcue, J.M. and J.O. Nriagu. 1993. Arsenic forms in mine polluted sediments of Moira Lake, Ontario. Environment International, 19:405-415.

Barrens, R. 1960. Report on Water Pollution Survey of the Moira River System. Ontario Water Resources Commission. 25 p.

Commonwealth Historic Resource Management Limited, 1987. A historical analysis of the Deloro Site. Draft report prepared for J.L. Richards & Associates, November 1987.

Cornett, J., L. Chant and B. Risto. 1992. Arsenic transport between water and sediments. Hydrobiologia, 235/236:533-544.

Mudroch, A. and J.A. Capobianco. 1980. Impact of past mining activities on aquatic sediments in the Moira River basin, Ontario. International Association for Great Lakes Research, 6:121-128.

Ontario Department of Planning and Development (ODPD). 1955. Moira Valley Conservation Report, Summary. Toronto.

Ontario Ministry of the Environment (MOE) 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Queens Printer for Ontario

Ontario Ministry of the Environment and Energy (MOE) 1999a. Water management policies: guidelines, provincial water quality objectives. Queens Printer for Ontario. Toronto, ON.

Ontario Ministry of the Environment and Energy (MOE) 1999b. Guidelines for use at contaminated sites in Ontario. Queens Printer for Ontario. Toronto, ON.

Ostray, R.C. and S.N. Singer. 1981. The Hydrogeology of the IFYGL Moira River, Wilton Creek and Thousand Islands Study Areas. Ontario Ministry of the Environment Water Resources Report 5e. 40 p.

Owen, G.E. and D.L. Galloway. 1969. Biological survey of the Moira River. Ontario Ministry of the Environment.

WSA. 1999. Moira River impact study: Detailed study design to determine the impact of the former Deloro Mine Site on the Moira River system. Final Report to Ontario Ministry of Environment.