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Project No. 421167 April 1987 Draft Report Endangerment Assessment Brio Refining Inc. Site and Dixie Oil Processors Site riendswood, Texas prepared for ^icassK.3SEa Brio Task Force RSV 0021510 ENDANGERMENT ASSESSMENT TABLE OF CONTENTS SECTION 1.0 INTRODUCTION 1.1 SITE DESCRIPTION AND HISTORY 1.1.1 Brio Refining Site 1.1.2 Dixie Oil Processors Site 1.1.3 History of Site Operations 1.1.3.1 Operations at the Brio Refining Site 1.1.3.2 Operations ae the Dixie Oil Processors Site 1.1.4 Additional Historical Background 1.2 SITE CHARACTERIZATION 1.2.1 Scope of the Chemical Analytical Data Base 1.2.1.1 Data Generated by the Remedial Investigation (RI) 1.2.1.2 Data Generated by*the Supplemental Remedial Investigation (SRI) 1.2.1.3 Endangerment Assessment Database 1.2.2 Suntnary of Chemical Analytical Data 1.2.2.1 RI Data 1.2.2.2 SRI Data 1.2.3 Statistical Rationale for SRI Tables 1.2.4 Quality and Validity of the Chemical Data 1.2.5 Extent of Contamination 1.2.5.1 Extent of Contamination - Ambient Air 1.2.5.2 Surface Soils - Extent of Contamination 1.2.5.3 Shallow Trench (Depth 2.5 feet) Near Pit Q 2.0 ENVIRONMENTAL FATE AND TRANSPORT 2.1 ENVIRONMENTAL TRANSPORT PARAMETERS 2.1.1 Physical and Chemical (of the Waste) Parameters 2.1.2 Hydrogeological Factors Influencing Transport 2.1.2.1 Concentration Levels 2.1.2.2 Geologic Features 2.2 SITE PHYSIOGRAPHY/TOPOGRAPHY 2.3 MIGRATION CHARACTERISTICS OF THEPRINCIPALCONTAMINANTS 3.0 EXPOSURE ASSESSMENT 3.1 RECEPTOR DEFINITION 3.1.1 Land Use 3.1.2 Demography 3.1.3 Socioeconomic Characteristics 3.1.4 Special Receptor Characteristics 3.1.5 Well Inventory 3.1.2 Ecology 3.2 EXPOSURE PATHWAYS 3.2.1 Ground Water Discharge to Mud Gully Impacting Aquatic Communities and Recreational WaterUse 3.2.2 Site Contamination Entering a DrinkingWater Supply 3.2.3 Flow From the NSC2 to the 50-Foot Sand 3.2.4 Sediment Migration Off-Site to Mud Gully 3.2.5 Contaminated Runoff to Mud Gully 3.2.6 Release of Airborne Particulates and Volatile Emissions 3.2.7 Contaminated Soil Ingestion Route of Exposure 3.2.8 Reversal of Gradient Between NSCZ and the 50 Foot Sand 1-1 1-4 1-4 1-5 1-5 i-5 1-8 1-9 1-10 1-11 1-11 1-11 1-13 1-13 1-13 1-15 1-15 1-15 1-16 i-16 i -- 16 i-i8 2-1 2-1 2-1 2-2 2-3 2-4 2-6 2-7 3-1 3-1 3-1 3-2 3-3 3-4 3-5 3-7 3-8 3-10 3*10 3-H 3-12 3-13 3-13 3-14 3-14 RSV 0021511 TABLE OF CONTENTS (Coneinued) SECTION 4.0 5.0 3.2.9 Fault and or Faulty Well Casing 3.2.9.1 Fault Number 70 3.2.9.2 Onsite Water Wells 3.3 EXPOSURE LEVELS AT THE RECEPTOR LOCATION 3.3.1 Ambient Air Exposure Pathway 3.3.1.1 Introduction 3.3.1.2 Estimation of the Receptor Ambient Air Concentrations (ExposureLevel) 3.3.1.3 Duration and Frequency of Exposure 3.3.l. Effective, Dose 3.3.1.5 Regression Analysis and Conversion Equation 3.3.2 Ground Water Pathway 3.3.2.1 Indicator Chemicals and Concentrations 3.3.2.2 Selection of NSCZ Monitoring Wells 3.3.2.3 Discharge to NSCZ to Hud Cully 3-3.2.** Stream Flow in Hud Gully 3.3.2.5 Dilution in Hud Gully 3.3.2.6 Dilution Scenarios 3.3.2.7 Concentrations in MixingZone 3.3-2.8 Comparison of Exposure Point Concentrations to Ambient Water Quality Criteria or Aquatic Toxicity Values HAZARD IDENTIFICATION 4.1 SELECTION OF THE INDICATOR CHEMICALS 4.1.1 Initial Procedure to Summarize Waste and Environmental Data 4.1.2 Identification of "High Risk" Chemicals 4.1.3 Physical, Chemical and Environmental Fate Data 4.1.4 Ranking of Constituents 4.1.5 Indicator Chemicals RI Data 4.2 FINAL INDICATOR CHEMICAL SELECTION 4.3 TOXICITY OF THE INDICATOR CHEMICALS - CARCINOGENICITY 4.3.1 Carcinogenicity Evaluation 4.3.2 Weight of Evidence for Carcinogenicity 4.4 SUBCHRONIC AND CHRONIC TOXICITY 4.5 ACUTE TOXICITY 4.6 DEVELOPMENTAL TOXICITY 4.7 DOSE-RESPONSE RELATIONSHIPS 4.8 EPIDEMIOLOGICAL EVIDENCE RISK CHARACTERIZATION (RISK AND IMPACT EVALUATION) 5.1 VOLATILE EMISSIONS TO AMBIENT AIR AND OFF-SITE IMPACTS 5.1.1 Carcinogenic Potency 5.1.2 Cancer Risk Calculations 5.2 DERMAL CONTACT AND INGESTION OF SURFACE SOILS 5.2.1 Ingestion of Surface Soils 5.2.2 Soil Concentration (Source of Exposure) 5.2.3 Toxicological Data - Animal Studies Used PAGE 3*15 3-15 3*16 3-16 3*16 3*16 3-17 3*18 3-19 3*19 3-19 3*20 3-20 3-21 3-22 3-2** 3-24 3-25 3*25 4-1 4-2 4-3 4-5 4-5 4-5 4-6 4-8 4-11 4-11 4-12 4-13 4-14 4-15 4-15 4-16 5-1 5-1 5-2 5-2 5-4 5-4 5-7 5-7 RSV 0021512 TABLE OF CONTENTS (Continued) SECTION PACE 6.0 7.0 8.0 9.0 5.2.4 Calculations of ChronicDailyIntake for Dermal Absorption and Oral Ingestion of Contaminants in On-Site Soil CONCLUSIONS INTER RISK COMPARISONS RISK MANAGEMENT TECHNICAL APPROACH FOR DEVELOPMENT OF REMEDIATION LEVELS AND COALS FOR THE FEASIBILITY STUDY ALTERNATIVES 8.1 REMEDIAL OBJECTIVES FOR PIT WASTES, SUBSOILS, AND IMPOUNDMENT SLUDGES 8.1.1 Technical Approach 1 8.1.2 Technical Approach **2 8.2 REMEDIAL OBJECTIVES FOR THE NSCZ * 8.2.1 Alternative 1 8.2.2 Alternative 2 8.3 REMEDIAL OBJECTIVES FOR MUD GULLY (SURFACEWATER) 8.3.1 Alternative 1 8.3.2 Alternative 2 8.4 REMEDIAL OBJECTIVES FOR MUD CULLY(SEDIMENTS) 8.5 REMEDIAL OBJECTIVES FOR AIR PATHWAY 8.6 REMEDIAL OBJECTIVES FOR PIT WASTES, CONTAMINATED SOILS, SUBSOILS AND IMPOUNDMENT SLUDGES FOR NON-CARCINOGENIC PARAMETERS 8.6.1 Residential Soil IngestionScenario 8.6.2 Infrequent Trespass SoilIngestionScenario 8.6.3 Carcinogenic PNAs 8.7 FEASIBILITY STUDY OBJECTIVES EVALUATION OF PUBLIC HEALTH ASPECTS OF FEASIBILITY STUDY ALTERNATIVES 5-9 6-1 7-1 8-1 8-4 8-5 8-6 8-7 8-7 8-8 8-8 8-8 8-8 8-9 8-9 8-10 8-11 8-12 8-12 8-13 9-1 REFERENCES APPENDICES BRO/ENDASS-TOC RSV 0021513 Appendix A Appendix B Appendix C LIST OF APPENDICES Supplemental Remedial Investigation Summary Statistics Carcinogenic Risk Calculations for Ambient Air Pathway Soil Ingestion and Skin Absorption Scenarios Non Carcinogenic Risk Calculations RSV 0021514 Table 1.1 Table 1-2 Table 1-3 Table 1-4 Table 1-5 Table 1-6 Table 1-7 Table 1-8A Table 1-88 Table 1-8C Table 1-80 Table 1-8E Table 1-8F Table 1-9A Table 1-98 Table 1-9C LIST OF TABLES List of Reported Residuals in the Brio Pits Scope of the Remedial Investigation Chemical Analytical Program - Brio Site Scope or the Remedial Investigation Chemical Analytical Program - Dixie Oil Processors Site Scope of the Supplemental Remedial Investigation Chemical Analytical Program - Brio Site Scope of the Supplemental Remedial Investigation Chemical Analytical Program - Dixie Oil Processors Site Chemical Analytical Data Used in the Endangerment Assessment - Brio Site Chemical Analytical Data Used in the Endangerment Assessment - Dixie Oil Processors Waste Pit Analytical Results Waste Pit Subsoils Chemical Analytical Results Monitoring Well Data Collected During Remedial Investigation - Brio Site Monitoring Well Data - Non Aqueous Phase Liquid Collected During Remedial Investigation Prevalence and Statistical Analysis of Chemical Analytical Results for the NSCZ Monitoring Well Data Collected During the Remedial Investigation - OOP Site Chemical Analytical Results NSCZ Ground Water (Supplemental Remedial Investigation) Sumary of SRI Analytical Results for Surface Water Samples Sumary of SRI Analytical Results for Pit Q Drainway and Mud Gully Sediments/Soil RSV 0021515 Table 2-1 Table 3-1 Table 3-2 Table 3-3 Table 3-4 Table 3-5 Table 3-6 Table 3-7 Table 3-8 Table U-1A Table 4-IB Table 4-ic Table 4-IQ Table 4-iE Table 4-IF Table 4-2 Table 4-3 LIST OF TABLES (Continued) Physical, Chemical and Environmental Fate Properties of Brio/DOP Contaminants Census Tract Population within a Four-Mile Radius Census Tract Population within a One-Mile Radius Census Tract Population within 1,000 Feet Water Well Inventory L One Mile Radius Toxicity Data for Aquatic Biota Indicator Chemicals and Concentrations Predicted Mud Cully Concentrations after Dilution of NSCZ Constituents from 13A and 18a versus Aquatic Toxicity Levels for Fresh Water Fish Predicted Mud Cully Concentrations after Dilution of NSCZ and Pits B, D, and Contributions versus Aquatic Toxicity Levels for Fresh Water Fish Physical/Chemical/Toxicological Ranking of Potential Indicator Chemicals in Heavily Contaminated Pits B, J and Q Physical/Chemical/Toxicological Ranking of Potential Indicator Chemicals in Waste Pit Residuals (data for moderately and lightly contaminated pits) Physical/Chemical/Toxicologioal Ranking of Potential Indicator Chemicals in Ground Water - NSCZ Toxicological Ranking (Details) of Potential Indicator Chemicals Physical/Chemical/Toxicological Ranking of Potential Indicator - Runoff to Mud Gully and Mud Cully Sediment Physical/Chemical/Toxicological Ranking of Potential Indicator Cheoicals-Subsoil and Wastewater Treatment System Sludges Toxicological Parameters for Constituents at Brio/DOP EPA Weight of Evidence Categories for Potential Carcinogens RSV 0021516 Table 4-4 Table 4-5 Table 4-6 Table 5-1 Table 5-2 Table 5-3 Table 5-4 Table 7-1 Table 8-12 Table 8-2 Table 8-3 Table 8-4A-D Table 8-5 Table 8-6 Table 8-7 Table 9-1 BRO/DJDASS-TOC LIST OF TABLES (Continued) Carcinogenicity Data and Weight on Evidence Ratings for Contaminants detected in the NSCZ Chronic Toxicity Parameters for the Indicator Chemicals Acute Toxicity Parameters for the Indicator Chemicals Calculated Cancer Risks at Off-Site Receptors Based on Modeled and Observed Ambient Air Concentrations Calculated Cancer Risks at Off-Site Receptors (Estimate of Modeled Values modified by Organic Chlorine Regression Equation) Chemical Concentration in Soil Non Carcinogenic Risk Characterization for Dermal Contact and Oral Ingestion Soil Exposure via Trespass Scenario Cancer Risks Associated with Voluntary and Involuntary Activity Allowable Concentrations of Pit Wastes, Contaminated Soils, Subsoils and Impoundment Wastes Based on Protection of Aquatic Species in Hud Cully (Technical Approach 1) Target Waste Clean-Up Levels to Protect Ground Water at 10* Cancer Risk Level (Technical Approach 2) Remedial Levels for NSCZ Constituents Based on Aquatic Protection of Mud Cully (Technical Approach 1 ) Mud Cully Sediment Data Appropriate Clean-Up Levels for Mud Gully Sediments Soil Clean-Up Levels for the Air Exposure Pathway Feasibility Study Objectives Comparison of Feasibility Study Closure Plans Effectiveness in Reduction of Toxicity and Mobility RSV 0021517 Figure 1-1 Figure 1-2 Figure 1-3 Figure 2-1 Figure 3-1 Figure 3-2 Figure 3-3 LIST OP FIGURES Brio end DOP Sices Vicinity Map Sice Location Map Sice Plan and Features Surface Water Drainage Patterns - Brio and DOP Sites Census Tract Population Map - One Mile and Four Mile Radius Water Well Inventory - One Mile Radius Idealized Potential Exposure Pathways BRO-'ENDASS-TOC RSV 0021518