I VJ hi- CL SALT CONTAMINATION ASSESSMENT & R EMEDIATION GUIDELINES /dibsrra ENVIRONMENT MAY 2001 Pub. No.: T/606 ISBN: 0-7785-1717-9 (Printed Edition) ISBN: 0-7785-1718-7 (On-Line Edition) Web Site: http://www.QOv.ab.ca/env/ Any comments, questions, or suggestions regarding the content of this document may be directed to: Environment Sciences Division Alberta Environment 4*^ Floor, Oxbridge Place 9820-106 Street Edmonton, Alberta T5K2J6 Phone: (780) 427-5883 Fax: (780) 422-4192 Additional copies of this document may be obtained by contacting: Information Centre Alberta Environment Main Floor, Great West Life Building 9920 -108 Street Edmonton, Alberta T5K 2M4 Phone: (780) 944-0313 Fax: (780) 427-4407 Email: [email protected] Page TABLE OF CONTENTS 1.0 INTRODUCTION 1 2.0 REGULATORY CONSIDERATIONS 2 2. 1 Environmental Protection and Enhancement Act 2 2.2 Role of the Energy and Utilities Board 3 2.3 Notification Requirements 3 2.3.1 Releases from Upstream Oil and Gas Facilities 3 2.3.2 Other Releases 4 2.4 Remediation Objectives 4 2.4. 1 Generic Guidelines 4 2.4. 1 . 1 Soil Quality Guidelines for Unrestricted Land Use 5 2.4. 1 .2 Soil Quality Guidelines for Commercial and Industrial Land Uses 6 2.4. 1 .3 Generic Water Quality Guidelines 6 2.4.2 Development of Site Specific Guidelines 7 2.4.2. 1 Site-Specific Risk Assessment 7 2.4.2.2 Risk Management Approach 7 2.5 Regulatory Closure 8 2.6 Additional Salt Contamination-Related Regulatory Documents 8 3.0 SITE ASSESSMENT AND REMEDIATION PROCEDURES 12 3 . 1 Site Assessment 12 3.1.1 Background Information 14 3.1.2 Site Assessment Plan 17 3.1.3 Site Assessment Procedure 18 3. 1 .3. 1 Visual Indicators of Salt Contamination 18 3. 1.3.2 Geophysical Tools 18 3 . 1 .3 .3 Site Description 19 3 . 1 .3 .4 Soil Sampling 19 3.1.4 Analysis and Interpretation of Samples 23 3 . 1 .4. 1 Laboratory Analysis 23 3. 1.4.2 Field Analysis 24 3 . 1 .4.3 Interpretation of Analytical Results 24 3.1.5 Groundwater Sampling and Analysis 24 3 . 1 .5 . 1 Installation of Observation Wells 25 3. 1.5. 2 Groundwater Monitoring and Chemical Sampling 28 3.1.6 Site Assessment Reporting 29 3 .2 Remediation Objectives 29 Salt Contamination Assessment & R emediation Guidelines i 3 .3 Remediation Options 29 3.3.1 Initial Salt Spill Response 32 3.3.2 In-Situ Remediation 33 3 .3 .2. 1 Required Site Conditions for In-situ Remediation 36 3 .3 .2.2 Replacement of Sodium in the Soil with Calcium 37 3 . 3 .2 . 3 Calcium Amendments 38 3. 3. 2. 4 Other Amendments 40 3 . 3 .2 . 5 Salt Leaching, Drainage, Containment and Disposal 40 3 .3 .2.6 Erosion Protection 44 3 .3 .2.7 Remediation of Salt-Contaminated Forest Soils and Wetlands 44 3.4 V erification of Remediation Success 45 4.0 RISK ASSESSMENT PROCEDURES 46 4. 1 Risk Assessment Conceptual Model 46 4.1.1 Receptors 47 4.1.2 Pathways of Exposure 47 4.1.3 Hazard 47 4.2 Level of Detail of Risk Assessments 50 5.0 REFERENCES AND SELECTED BIBLIOGRAPHY 53 6.0 APPENDIX A - B ACKGROUND INFORMATION 57 A1 .0 Sources of Salt 57 A 1 . 1 Produced Water 57 A1.2 Road Salt 57 A 1 .3 Excavation of Subsoil Material 57 A 1 .4 Other sources 58 A2.0 Naturally Occurring Saline and Sodic Soils 58 A2.1 Saline Soil 59 A2.2 Sodic Soil 60 A2.3 Saline-Sodic Soil 60 A2.4 Alberta Soils 6 1 A2.5 Natural Salinization of Soils 61 A3 .0 Movement of Salts in Soil and Groundwater 63 A3 . 1 Water Movement in Soil 63 A3 .2 Salt Movement in Soil 66 A3 .3 Computer Modeling of Soil Salinity and Plant Growth 67 A4.0 Effects of Salt on Soil, Vegetation, and Groundwater 67 A4. 1 Initial Effects of a S alt Water Release on the Soil 68 Salt Contamination Assessment & R emediation Guidelines ii A4.2 Effect of Soil Salinity on Vegetation 68 A4.3 Soil Structure and Effects of Excess Sodium and Dispersion 71 A4.4 Remediation of Saline-Sodic Soil by Replacement of Exchangeable Sodium with Calcium 76 A4.5 Soil Nutrients and pH 76 A5.0 References and Selected Bibliography 77 7.0 GLOSSARY 81 Salt Contamination Assessment & R emediation Guidelines iii LIST OF TABLES Page Table 2.1 Generic Guidelines for Salt Contaminated Soil 5 Table 2.2 Soil Quality Guidelines for Unrestricted Land Use 6 Table 2.3 Commercial/ Industrial Soil Quality Guidelines 6 Table 2.4 Selected Canadian Water Quality Guidelines 7 T able 2.5 S alt Contamination-Related Regulatory Documents 9 Table 2.6 Sources of Contamination-Related Regulatory Documents 1 1 T able 3.1 T ypes of Background Information 16 Table 3.2 Baseline Information (derived from Dudas 1997) 20 Table 3.3 Important Salinity, Soil, and Groimdwater Parameters for Characterization of Spills (adapted from PITS, 1993) 26 Table 3.4 Soil Remediation Options 34 Table 3.5 Most Commonly Used Calcium Amendments , 39 Table 3.6 Irrigation Water Quality Guidelines (Alberta Agriculture 1983) 42 Table A. 1 Selected Properties and Ions of Formation Waters from the Alberta Basin 58 Table A.2 Selected Ion Concentrations from Seawater, River Water, and Brines 59 Table A.3 Salt Related Chemical Parameters of Typical Soils in Alberta 62 Table A.4 Typical Orders of Magnitude of Steady Infiltration Rate for Selected Soils 64 Table A.5 Approximate Rate of Movement of Water in Saturated Soil 65 Table A.6 Ttoshold ECs and Yield Loss due to Salinity 70 Table A.7 Relative Sensitivity to Soil Salinity of Selected Plants 70 Salt Contamination Assessment & R emediation Guidelines iv LIST OF FIGURES Page Figure 3.1 Overall Assessment and Remediation Process Flow Chart 13 Figure 3.2 Capability Assessment and Site Investigation Flow Chart 1 5 Figure 3.3 Determination of Appropriate Soil Remediation Objectives Flow Chart 30 Figure 3.4 Remediation Flow Chart 31 Figure 4.1 Potential Sources, Pathways and Receptors of Dissolved Salt - D evelopment of Conceptual Plan 49 Figure 4.2 Conceptual Model of Flow Pathways 50 Figure 4.3 Risk Assessment - D ecisions on Level of Detail (CCME 1 996a) 5 1 Figure A. 1 Example of Mechanism of a S aline Seep Formation 67 Figure A.2 Adverse Effects of Sodium on Soil 72 Figure A.3 Dispersive Behaviour of Saskatchewan Soils in Relation to SAR and EC 74 Figure A.4 Reduction in Hydraulic Conductivity Caused by Leaching Soils that have Various Exchangeable Sodium Percentages (ESP) with Tap Water 75 Figure A.5 Combinations of Electrolyte (Salt) Concentration and SAR that Produce a 25% Reduction in Hydraulic Conductivity in Selected Saskatchewan Soils 76 Salt Contamination Assessment & R emediation Guidelines V ' : ^ vl t-t • «■! ■ •^'2. "4 u ■— Iw A 1.0 Introduction 1.0 INTRODUCTION Releases of salt to land often occur in association with activities such as oil and gas production, salt/sand processing and storage facilities at highway maintenance yards, rendering plants, runoff from snow removal dumps and the transportation of saline material for industrial use. These salts can be very mobile and may easily move with water over the surface or down through soil. Typical environmental impacts associated with excess salt in soil and surface water or groundwater are: • Degradation of soil chemical properties and impaired vegetative growth; • Degradation of soil physical properties caused by excess sodium concentrations; and • Degraded surface water or groundwater quality. The most efficient and cost effective method of avoiding adverse effects aind the attendant remediation costs associated with salt releases is spill prevention. When spills do occur, a f ast, effective response based on a comprehensive understanding of impacts, salt movement, and assessment and remediation procedures can avoid or mitigate adverse effects on the environment. The intent of this Guideline is to: • Summarize regulatory requirements in Alberta, including salt remediation objectives; • Develop awareness and understanding of the salt spill problem and the necessity for effective and complete remediation; and • Provide an overview of effective site assessment and remediation procedures. This document is designed to assist those involved in prevention, assessment, remediation and management of salt-contaminated sites. Appendix A p resents background information for those who desire a more complete understanding of industry sources of salt, saline/sodic soils, movement of salts in soil and groundwater, and adverse effects of salt on soil, vegetation, and groundwater. A g lossary is also provided. Salt Contamination Assessment & R emediation Guidelines 1 2.0 Regulatory Considerations 2.0 REGULATORY CONSIDERATIONS 2.1 Environmental Protection and Enhancement Act Remediation of salt-affected land must meet requirements of Alberta’s Environmental Protection and Enhancement Act (Province of Alberta, 1992). The Act states the importance of preventing environmental impacts and the obligation of responsible parties to remediate areas adversely affected by a substance release (e.g., salt release). In order to meet these requirements, all the following conditions must be met: • Contaminant concentrations must meet remediation objectives (background levels, generic guidelines or site-specific risk-based objectives) or better. • Any residual contamination must not adversely affect current receptors or other potential receptors possible under the existing land use. • Capability of the affected area must not be any more limiting after remediation than before the spill. Part 4, Division 1 of the Environmental Protection and Enhancement Act (Province of Alberta 1992) addresses "Release of Substances Generally”. Releases of saline material would be included in these provisions. Some of the issues addressed by subsections 97 to 104 include: • Prohibition of release of substances exceeding approvals or regulations; • Unauthorized release of substances that may cause adverse effects; • Duty to report a r elease; • Manner of reporting a r elease; • Duty to take remedial measures; • Issuance of environmental protection orders and emergency environmental protection orders regarding a r elease; and . Emergency measures that may be taken. The Release Reporting Regulation (Alberta Regulation 117/93, Province of Alberta, 1993a, as amended) includes subsections on substances governed by federal acts, substance release reports, and exemptions fi-om reporting. Under Alberta’s Environmental Protection and Enhancement Act the guiding principles for industrial activities and remediation efforts are: 1. Prevention, and mitigation if necessary, of adverse effects caused by the release of substances into the environment (Part 4, Release of Substances); and Salt Contamination Assessment & R emediation Guidelines 2