Canadian Council of Ministers of the Environment

What is the Canada-Wide Standard for  Petroleum Hydrocarbons (PHC) in Soil?

PHC consist of a wide range  of organic compounds found in or derived from geological sources such as oil,  coal and bitumen, including a variety of raw and refined fuels and lubricants.  They provide energy to heat our homes and places of work, fuel our  transportation systems, power manufacturing processes and tools, and provide a  source for numerous synthetic materials.

However, when PHC are  released to soil they cause a wide variety of problems related to their  toxicity, mobility and persistence.

The CWS for PHC in soil is  a remediation standard that sets out the levels to which sites contaminated by  PHC must be cleaned up to - if and when they are subject to remediation.  

The proposed standard sets  out generic target levels, as well as a process for generating site-specific  numbers, that are protective of both human and ecological health. The CWS is  risk-based, having been founded on the most recent and comprehensive body of  science. The standard provides for consistent and effective management of  PHC-contaminated sites across Canada.

What is the science on Petroleum  Hydrocarbons?

PHC released to the  environment are complex mixtures, typically containing thousands of compounds,  in varying proportions. The properties of PHC contamination in soils varies with  the petroleum source, soil type, the composition, degree of processing (crude,  blended or refined), and the extent of weathering caused by exposure to the  environment. PHC contamination can cause a number of problems:  

·        Their chemical reactivity  and volatile nature can pose a fire/explosion hazard, especially if vapours  enter confined spaces.

·        Most constituents are toxic  to some degree for human and/or environmental health.

·        Lighter hydrocarbons (i.e.,  those of lower molecular weights) are mobile and can be transported considerable  distances in groundwater or air.

·        Larger and branched-chain  hydrocarbons are persistent in the environment.

·        PHC may create aesthetic  problems such as offensive odour, taste or appearance.

·        Under some conditions, PHC  can degrade soil quality by interfering with water retention and flow, and with  nutrient supplies for plants.

The differing properties of  PHC are related to the size of the  PHC molecules.  In this CWS, PHC are  grouped into four size fractions to effectively assess and manage the risks they  pose to the environment and human health.

Extent of the  problem

Petroleum hydrocarbons are  one of the most widespread soil contaminants in Canada.  The majority of contaminated sites contain  PHC.  There are tens of thousands of  contaminated sites across Canada.

Currently, management of  contaminated sites varies considerably across Canada and generally lacks an  adequate scientific basis.

Achieving the  Standard

The proposed PHC CWS is  unique in that it does not include a timeframe for implementation.  

The standard does not  itself trigger clean-up of PHC-contaminated sites, but does require a consistent  level of clean-up when remediation  takes place, to ensure protection of human health and the environment.  Governments will report on implementation of the standard in 2003 and every five  years thereafter.

Science, technology and  economics related to PHC management will be reviewed in 2003. Incorporation of  new and emerging information will ensure continued improvement in the management  of PHC-contaminated sites.

The CWS will be used by  industry and governments in their operations and reclamation activities, and by  governments in setting control requirements.

How Will PHC-Contaminated  Sites be Identified and Addressed?

Under the PHC CWS the  processes of site identification and remedy selection are implementation issues  for individual jurisdictions.    However,  across jurisdictions, the most common factors that make sites priorities include  known release, complaints, requirements of a licence or approval, land  re-development or transfer, and decommissioning.  When one or more of these factors triggers  site assessment, the PHC CWS can be used to ensure that effective and consistent  remediation occurs.

Further information is  available from the CCME’s website (www.ccme.ca).

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