Lower Trent Region Conservation Authority Lower Trent River: Preliminary Quantitative Human Health Risk Assessment Submitted by Dillon Consulting Limited File #: 06 -5735 Date: July, 2006 Executive Summary In 1985, the Bay of Quinte was identified as a Great Lakes Area of Concern (AOC) by Bi­ national Great Lakes Water Quality Agreement between Canada and the United States. The movement of contaminated sediments into the Bay of Quinte from the Trent River has been identified as a potential concern. In preparation for delisting the AOC, the Bay of Quinte RAP Restoration Council had decided (circa 2000) to verify that natural recovery was occurring. As part of this process there is a need to identify the environmental fate of contaminants, possible transport pathways and toxic effects to determine the potential for these contaminants to have adverse effect on human health for recreational users of the Lower Trent River. As part of the ongoing monitoring work to assess sediment quality and to provide the information necessary to develop an appropriate RAP, the Ontario Ministry of the Environment (MOE) and Environment Canada (E.C.) undertook extensive sediment sampling in 2000 and 2001. This work identified the presence of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) at concentrations that exceeded background sites in the Bay of Quinte. An additional six (6) sediment samples were collected by E.C. in 2004. The PCDD/PCDF levels in these latter samples were among the highest for depositional basin sediments in Lake Ontario and are above the Canadian Council of Ministers of the Environment (CCME) human health-based screening criterion of 4 pg TEQ/g of soil. In order to complete the actions required under the Canada-Ontario Agreement (COA), a Preliminary Quantitative Risk Assessment (PQRA) was used to identify potential human health concerns related to exposures to contaminants in the sediments and surface water in the Lower Trent River and at the mouth of the Trent River. The objective of the PQRA evaluated potential human exposures to PCDD/PCDF and other contaminants in the sediments in the Lower Trent River and in the Bay of Quinte at the mouth of the Trent River that could occur as a result of recreational uses (boating and swimming or wading) of the river and Bay of Quinte in the vicinity of the river mouth. The PQRA also established a Site-Specific Intervention Level (SSIL) for sediments. This SSIL represents the maximum PCDD/PCDF concentration (expressed as pg TEQ/g sediment) that could be present in sediments to ensure that exposures would not exceed acceptable levels. The PQRA compared the concentrations of metals, PCB, polycyclic aromatic hydrocarbons (PAH), organochlorine poesticides and other organochlorine compounds, as well as PCDD/PCDFs, to MOE residential standards to identify contaminants that are present at sufficient concentrations to be considered of potential concern to human health. Based on the screening process, PCDD/PCDF were the only contaminants identified as contaminants of concern. The PQRA focused on recreational exposures to sediments for children, teens and adults. The potential routes of exposure for these receptors included incidental ingestion of sediment and dermal contact with sediments. Exposure and hazards were evaluated for these pathways for each of the relevant receptors. Infants and preschool-aged children are not expected to come into Lower Trent Region Conservation Authority Page i Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited contact with sediments in the Lower Trent River or at the river mouth and, therefore, have not been included in the assessment. The results of the PQRA indicate that exposures to PCDD/PCDF experienced by children, teens and adults do not pose a risk to human health. Based on the results of the risk assessment, a SSIL of 4,300 pg TEQ/g sediment was calculated for the study area. Based upon currently available data, PCDD/PCDF concentrations in sediment in the Lower Trent River and the Bay of Quinte at the mouth of the Trent River do not exceed the SSILs calculated for the receptors considered in the assessment. From the results of the PQRA it can be concluded that: ¾ Investigations of contaminant concentrations in sediments in the Lower Trent River and in the Bay of Quinte, at the mouth of the Trent River, shows that the maximum concentration of most contaminants are below the levels that would be allowable in residential soil. Therefore, these contaminants do not pose risks for people using the Lower Trent River or the river mouth area for recreational purposes. ¾ The maximum concentrations of benzo[a]pyrene, lead and mercury exceed the limits that would be considered acceptable in residential soil. In all three cases, concentrations that exceed the residential standards are limited to single samples. For all three contaminants, the maximum reported concentrations are marginally above the residential standards. In all other samples, the concentrations of these three contaminants are below the residential standards. Therefore, exposures to these three contaminants across the study area do not represent human health concerns. ¾ The risk assessment focused on PCDD/PCDF concentrations in the top 20 cm sediment horizon. PCDD/PCDF concentrations exceeded interim residential standards in 34 of 73 samples taken from the top 20 cm horizon. The risk assessment showed that PCDD/PCDF in sediments (in the top 20 cm horizon) in the Lower Trent River and the Bay of Quinte, at the mouth of the Trent River, do not pose a risk to human health for people who use the area for recreational activities such as boating, swimming or wading. ¾ The maximum PCDD/PCDF concentration reported in the top 20 cm horizon (1,297 pg TEQ/g) is below the SSIL of 4,300 pg TEQ/g calculated for the sediments. The SSIL represents the maximum concentration that could be present in the sediments before exposures for the child receptor could exceed the Hazard Acceptability Benchmark of 0.2 ¾ Review of the PCDD/PCDF concentrations in sediment from below the 20 cm horizon were all below the SSIL calculated in the risk assessment. Based on the results of the PQRA, the following recommendations can be made: ¾ Measures to limit human exposures to the sediments in the Lower Trent River and the Bay of Quinte at the mouth of the Trent River are not necessary; ¾ The results of the PQRA shows that exposures to PCDD/PCDF and other contaminants do not pose a potential risk to human health. Given that the PQRA, which is designed to over estimate potential exposures and the associated risks, indicates that human health Lower Trent Region Conservation Authority Page ii Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited concerns are not present for the study area, the completion of a detailed human health risk assessment to reduce the level of conservatism in the risk assessment is not necessary. ¾ The presence of single samples, where the concentrations of benzo[a]pyrene, lead and mercury exceed residential standards, do not represent hot-spots. Additional investigation to delineate these areas is not required to address potential human health concerns. Lower Trent Region Conservation Authority Page iii Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited TABLE OF CONTENTS Executive Summary......................................................................................................................... i 1.0 Introduction.............................................................................................................................1 1.1 Background................................................................................................................... 1 1.2 Scope and Objectives.................................................................................................... 2 1.3 Organization of Report ................................................................................................. 2 1.4 Limitation...................................................................................................................... 2 2.0 Site Characterization...............................................................................................................4 2.1 Site Description............................................................................................................. 4 2.1.1 Site Location and Land Use........................................................................... 4 2.1.2 Hydrogeology ................................................................................................ 4 2.2 Summary of Available Data.......................................................................................... 4 2.2.1 Sediment Quality Data................................................................................... 4 2.2.1.1 Metals Levels in Sediments ............................................................ 5 2.2.1.2 PCB Levels in Sediments............................................................... 6 2.2.1.3 PAH Levels in Sediments .............................................................. 6 2.2.1.4 Organochlorine Compound Levels in Sediments .......................... 6 2.2.1.5 Chlorophenol Levels in Sediments ................................................. 7 2.2.1.6 PCDD/PCDF Levels in Sediments ................................................ 8 2.2.2 Surface Water Data...................................................................................... 10 3.0 Problem Formulation ............................................................................................................11 3.1 Identification of Contaminants of Concern................................................................. 11 3.1.1 Identification of Contaminants of Concern in Sediments............................ 11 3.1.1.1 Screening for COCs in Sediments: Metals ...................................... 12 3.1.1.2 Screening for COCs in Sediments: PCB.......................................... 14 3.1.1.3 Screening for COCs in Sediments: PAH ......................................... 15 3.1.1.4 Screening for COCs in Sediments: Organochlorine Compounds.... 16 3.1.1.5 Screening for COCs in Sediments: Phenols & Chlorophenols........ 18 3.1.1.6 Screening for COCs in Sediments: PCDD/PCDF ........................... 19 3.1.2 Identification of Contaminants of Concern in Surface Water ..................... 19 3.2 Identification of Potential Receptors .......................................................................... 21 3.3 Site Conceptual Model............................................................................................... 22 4.0 Exposure Assessment............................................................................................................23 4.1 Receptor Characteristics ............................................................................................. 23 4.1.1 Physical and Physiological Factors.............................................................. 23 4.1.2 Receptor Activity Patterns ........................................................................... 24 4.1.3 Exposure Averaging Factors........................................................................ 25 4.1.3.1 Event-Driven Exposure Averaging Factors................................. 25 4.1.3.2 Calculating Exposure Averaging Factors .................................... 26 4.2 Estimating Exposure to PCDD/PCDF Within the Study Area ................................... 26 Lower Trent Region Conservation Authority Page iv Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited 4.2.1 Incidental Ingestion of Sediment ................................................................. 26 4.2.2 Dermal Contact with Sediment................................................................... 28 4.2.3 Quantifying Total Daily Exposures ............................................................. 30 5.0 Toxicity Assessment .............................................................................................................31 5.1 General Information.................................................................................................... 31 5.2 Regulatory Exposure Limits ...................................................................................... 31 5.3 Animal Toxicology ..................................................................................................... 32 5.4 Human Health Effects................................................................................................. 32 5.5 Opinions of Various Regulatory Agencies ................................................................. 33 6.0 Risk Characterization and Calculation of Site-Specific Intervention Levels .......................34 7.0 Discussion of Uncertainties ..................................................................................................36 7.1 Site-Occupancy Assumptions ..................................................................................... 36 7.2 PCDD/PCDF Concentrations in Sediments................................................................ 36 7.3 Consideration of Non-Site-Related Exposure Pathways ............................................ 36 7.4 Consideration of Sport Fish Consumption.................................................................. 37 8.0 Conclusion and Recommendations.......................................................................................38 8.1 Conclusions................................................................................................................. 38 8.2 Recommendations...................................................................................................... 39 9.0 Glossary ................................................................................................................................40 10.0 References.............................................................................................................................44 Lower Trent Region Conservation Authority Page v Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited LIST OF TABLES Table 2-1: Maximum Reported Metals Concentrations in Sediments............................................ 5 Table 2-2: Maximum Reported PCB Concentration in Sediments............................................ 6 total Table 2-3: Maximum Reported PAH Concentrations in Sediments............................................... 6 Table 2-4: Maximum Reported Organochlorine Compound Concentrations in Sediments........... 7 Table 2-5: Maximum Reported Chlorophenol Concentrations in Sediments................................. 8 Table 2-6: Toxic Equivalency Factors for PCDD/PCDF & DLPCB ............................................. 9 Table 2-7: Maximum Reported PCDD/PCDF Concentration in Sediment (0 – 20 cm) ................ 10 Table 2-8: Maximum Reported Metal Concentrations in Surface Water..................................... 10 Table 3-1: Sediment Screening: Metals........................................................................................ 12 Table 3-2: Sediment Screening: PCB ........................................................................................... 15 Table 3-3: Sediment Screening: PAH........................................................................................... 15 Table 3-4: Sediment Screening: Organochlorine Compounds ..................................................... 17 Table 3-5: Sediment Screening: Phenols & Chlorophenols ......................................................... 18 Table 3-6: Sediment Screening: PCDD/PCDF............................................................................. 19 Table 3-7: Surface Water Screening: Metals................................................................................ 20 Table 3-8: Potentially Complete Exposure Pathways Lower Trent River Study Area................. 22 Table 4-1: Physical, Physiological and Behavioural Parameters.................................................. 23 Table 4-2: Activity Pattern Assumptions for Swimmers & Waders in Lower Trent River ......... 24 Table 4-3: Exposure Averaging Factors for Recreational Receptors ........................................... 26 Table 4-4: Incidental Ingestion Exposures to PCDD/PCDF in Sediments................................... 28 Table 4-5: Dermal Contact Exposures to PCDD/PCDF in Sediments ........................................ 30 Table 4-6: Estimating Total Daily Exposure to PCDD/PCDF in Sediments................................ 30 Table 6-1: Hazard Quotients and Site-Specific Intervention Levels for Sediments..................... 35 LIST OF FIGURES Figure 1: Site Location Figure 2: Ontario Ministry of the Environment 2005 Sampling Locations; Figure 3: Environment Canada 2005 & 2005 Sampling Locations Figure 4: Conceptual Site Model LIST OF APPENDICES Appendix A: Environmental Quality Data for Sediments (0 - 20 cm) and Surface Water Appendix B: Environmental Quality Data for Sediments (> 20 cm) Lower Trent Region Conservation Authority Page vi Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited 1.0 Introduction 1.1 Background In 1985, the Bay of Quinte was identified as a Great Lakes Area of Concern (AOC) by the International Joint Commission. The movement of contaminated sediments into the Bay of Quinte from the Trent River has been identified as a potential concern. Management of sediments has been identified as part of the remediation effort. Prior to the management of sediments, there is a need to identify the environmental fate of contaminants, possible transport pathways and toxic effects to determine the potential for these contaminants to contribute to the impairment of the Bay of Quinte AOC. Canada and Ontario, under the Canada-Ontario Agreement (COA), are working to understand, restore and protect environmental quality in the Bay of Quinte AOC. As part of this agreement, contaminated sediments in the Lower Trent River must be dealt with in a manner that is deemed appropriate under the COA and the Remedial Action Plan (RAP) that has been developed for the Bay of Quinte AOC. As part of the ongoing monitoring work to assess sediment quality and to provide the information necessary to develop an appropriate RAP, the Ontario Ministry of the Environment (MOE) and Environment Canada (E.C.) undertook extensive sediment sampling in 2000 and 2001. In 2000, sediment cores were collected as part of a comprehensive investigation of sediment quality in the Bay of Quinte. Cores were needed to confirm the quality of sediment at depth in order to update the status of the restrictions on dredging impairment. This work identified the presence of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) at concentrations that exceeded background sites in the Bay of Quinte. An additional six (6) sediment samples were collected by E.C. in 2004. The PCDD/PCDF levels in these latter samples were above the Canadian Council of Ministers of the Environment (CCME) human health-based screening criterion of 4 pg TEQ/g of soil (4.0 pg Toxicity Equivalents/g soil). The CCME soil screening criterion is used to assess sediment quality when evaluating potential human exposures to sediments. In order to complete the actions required under the COA for the Bay of Quinte Remedial Action Plan (RAP), contaminated sediment issues at the mouth of the Trent River must be dealt with to a level deemed appropriate by the RAP. This Preliminary Quantitative Risk Assessment (PQRA) will be used to identify potential human health concerns related to direct exposures to contaminants in the sediments and surface water in the Lower Trent River and at the mouth of the Trent River. Indirect exposures to contaminants through such pathways as the consumption of sport fish have not been incorporated into the PQRA. The results of the PQRA will be used in conjunction with other on-going studies to determine the measures necessary to provide adequate protection of human health and the environment. Lower Trent Region Conservation Authority Page 1 Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited 1.2 Scope and Objectives The objective of the PQRA is to evaluate potential human exposures to PCDD/PCDF and other contaminants in the sediments in the Lower Trent River and the Bay of Quinte, at the mouth of the Trent River. For the purposes of this assessment, the term PCDD/PCDF is intended to include dioxin-like PCB (DLPCB). The PQRA will also be used to establish a Site-Specific Intervention Level (SSIL) for sediments. This SSIL represents the maximum PCDD/PCDF concentration (expressed as pg TEQ/g sediment) that could be present in sediments to ensure that exposures would not exceed acceptable levels. The concept of toxicity equivalents (TEQ) is discussed in Section 2.2.1.5. The PQRA focuses only on recreational activities that could result in people coming into direct contact with sediments in the Lower Trent River or at the mouth of the Trent River. The PQRA was conducted in accordance with the regulatory guidance provided in Ontario Regulation 153/04 and the associated supporting documentation. Guidance from other regulatory agencies such as Health Canada (Health Canada, 2004) and the U.S. EPA superfund program (USEPA,1989) were used when deemed appropriate. 1.3 Organization of Report This report is organized into 10 sections and 2 appendices, of which this introduction is the first. Section 2 provides a summary of the environmental and biological monitoring data available for the Lower Trent River area. Section 3 presents the Problem Formulation that identifies the contaminants of concern, the potential receptors and the active or complete exposure pathways. Section 4 presents the results of the Exposure Assessment. Section 5, the Toxicity Assessment, provides a listing of the toxicological reference values used to assess the potential hazards/risks associated with exposure to the contaminants of concern. Section 6 characterizes the risks associated with exposure to contaminants in the sediments for the identified receptors. Section 7 provides a discussion of the uncertainties associated with the hazard estimates from the PQRA. Section 8 provides a summary of the recommendations and conclusions stemming from the PRQA. Section 9 provides a glossary of terms used in this report. Section 10 lists the citations for the reference materials used in the development of the PQRA. Appendix A provides a listing of the soil, sediment and surface water monitoring data that have been used to identify the maximum contaminant concentrations in sediment in the Lower Trent River. Appendix B provides a listing of the sediment quality data for sediment horizons below 20 cm. It should be noted that these data have been provided for completeness and have not been used in the present report. 1.4 Limitation Risk assessments, by their nature, have inherent limitations and uncertainties. It is believed that these uncertainties have been addressed through the conservative interpretation of site-specific data and parameter selection, and in the conservatism inherent in existing toxicity information. The quantitative estimates of risk provided by this process are valid only for the assumptions and Lower Trent Region Conservation Authority Page 2 Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited exposure scenarios outlined in this report. However, should knowledge of the site conditions or toxicity information change, the risk posed by the site may differ from that presented in this report. This report was prepared exclusively for the purposes, project, and site location outlined in the report. The report is based on information provided to, or obtained by Dillon, as indicated in the report, and applies solely to site conditions existing at the time of the site investigation. Where the risk assessment has relied on information provided to Dillon by the other parties, Dillon has, within the scope and expectations of the risk assessment process, reviewed this data but Dillon does not warrant the accuracy, completeness and representativeness of this information. Dillon’s report represents a reasonable review of available information within an established work scope, work schedule, and budget. This report was prepared by Dillon for the sole benefit and use of the Lower Trent Region Conservation Authority, the Ontario Ministry of the Environment and Environment Canada. The material in it reflects Dillon’s best judgement in light of the information available to it at the time of preparation. Any use which a third party makes of this report, or any reliance on or decision made based on it, are the responsibilities of such third parties. Dillon accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this report. Lower Trent Region Conservation Authority Page 3 Preliminary Quantitative Human Health Risk Assessment July, 2006 Lower Trent River Dillon Consulting Limited