Information letter: Salt contamination assessment and remediation requirements

Delineation of salt contaminants

IOGC has applied a conservative approach to the assessment and remediation of salt contamination from oil and gas operations, including, but not limited to, produced water releases (primarily sodium chloride) or drilling waste. Surface contract holders (contract holders) are required to fully delineate the vertical and lateral extent of key indicators of salt contamination (contaminants) in soils, including:

• chloride
• electrical conductivity (EC)
• pH (potential of hydrogen)
• sodium
• sodium adsorption ratio (SAR)
• sulphate

What guidelines apply on designated First Nation lands

Contract holders are required to:

• remediate salt contaminated sites to the applicable land use guideline as per the Canadian Council of Ministers of the Environment Canadian Environmental Quality Guidelines (CCME Guidelines) for EC, pH, and SAR
• assess naturally occurring background levels for chloride, sodium and sulphate in soil, as the CCME Guidelines do not include these parameters
• remediate salt contaminated sites to naturally occurring background levels for chloride, sodium and sulphate in soil

Note: IOGC requires contract holders to apply agricultural land use CCME Guidelines unless an alternative approach has been formally approved through the informed consent of the First Nation through a signed Band Council Resolution (BCR) and approval by IOGC. For additional details, please refer to the related links provided.

Consideration of approaches for extensive salt contamination

IOGC may consider the following environmental site assessment and remediation approaches for sites with extensive salt contamination in soil and groundwater and where meeting CCME Guidelines is not feasible due to site restriction or physical or engineering limitations.

• Plant root zone: from surface to the depth of 3 metres
  • All key soil salt contaminants are required to be assessed and remediated to meet the applicable CCME Guidelines for pH, EC, and SAR, as well as assessed background levels for chloride, sodium, and sulphate, which do not currently have CCME Guidelines values.
• Subsoil and groundwater: below 3 metres and the plant root zone
  • Contract holders must consult with the First Nation and IOGC's Environment Business Unit for CCME Guidelines deviations in subsoil and groundwater.
  • Implementation of a site-specific approach requires informed consent of the First Nation through a signed BCR and approval by IOGC. This includes the use of:
    • provincial groundwater remediation guidelines for assessment and remediation of salt contaminants in groundwater
    • Alberta Tier 2 soil and groundwater remediation guidelines generated using the Subsoil Salinity Tool (Version 3.0 User Manual and all subsequent updates) (PDF) for assessment and remediation of salt contaminants in both soil and groundwater

Ensuring adequate naturally occurring soil salt background data

IOGC recognizes that naturally occurring background levels of chloride, sodium, and sulphate in soil vary depending on local geology, hydrogeology, and surface water conditions. Contract holders are required to assess background soil quality concentrations for these parameters using scientifically defensible, site-specific methods, and, until further guidance is provided by IOGC, follow the applicable provincial approach^{Footnote 1} to establishing background levels.

Inapplicability of Alberta Tier 1 chloride groundwater guideline for assessment and remediation of soil chloride contamination

IOGC does not currently accept the use of the groundwater chloride guideline from the Alberta Tier 1 soil and groundwater remediation guidelines to assess and to remediate soil chloride contamination. IOGC has not confirmed that the available scientific evidence demonstrates the chloride groundwater guidelines are protective of soils.

For more information

• For environment-related remediation questions, email IOGC-environment-notification@sac-isc.gc.ca or contact the designated Environmental Analyst by First Nation lands.

Related links

• Alberta Tier 2 soil and groundwater remediation guidelines
• Canadian Soil and Water Quality Guidelines for the Protection of Environmental and Human Health: In Canadian Environmental Quality Guidelines
• Contact list by First Nation lands
• Environmental requirements and updates (include remediation and reclamation information)
• First Nation profiles
• Forms
• Indian Oil and Gas Regulations, SOR/2019-196
• Information letter: Application of remediation guidelines and risk-based methodologies
• Subsoil Salinity Tool Version 3.0 User Manual (Alberta) (PDF)