Part 2 – See our Insights section for Part 1 and for an overview of how guidelines are developed
There is an old saying that the dose makes the poison, accredited to Paracelsus, the father of toxicology. We can observe this in effect when we drink alcohol, a small amount has virtually no long-term effect, but drink enough and the next morning the symptoms of alcohol poisoning can be obvious. In general, biological systems have adapted to deal with some level of most chemicals. It is not until that capacity is exceeded that damage to the system occurs. The goal when cleaning up a site is to make sure that capacity is not exceeded in any system, whether it is humans being exposed or the bacteria and worms in the soil that allow healthy plant life to grow.
On any spill site, environmental professionals should be called in to assess the risk posed and develop a plan of action to make sure any excessive risk is removed as soon as possible and that any ongoing risk is managed in a way that prevents actual harm from occurring. A professional will be able to determine if the contamination is likely to reach a nearby river or human water supply, or if there are sensitive species that need to be considered. The priority is always to contain the source to keep the problem from growing. Quick spill response is essential for industry to minimize the damage caused. On most sites, there will be some amount of excavating the contaminated soil, ideally before the chemical sinks too deep into the ground. Spills in water are considerably more difficult to manage. If the spill is oil, booms may be used to contain the spill while trucks suck up the water on the surface for treatment. Once that is complete, the focus shifts to determine the best course of action to reduce the risk to acceptable levels.
Sometimes you cannot remove the chemical to a degree that any remaining soil or water meets the guidelines, either due to risk involved in the removal such as steep banks, or tight quarters with other infrastructure in developed areas. In some cases, it may cause more environmental damage to remove contaminated soil than to leave it in place, particularly in areas susceptible to erosion. On a large spill site, the costs involved in excavating and sourcing clean soil to fill the hole can be tens to hundreds of millions of dollars, and a bankrupt company cannot continue cleanup efforts. All the competing risks must be weighed when deciding on the best course of action. For a site where the contamination cannot be removed quickly, options may include treating the contamination in place (e.g. flushing water through the soil or injecting bacteria) or as a last resort putting engineered controls in place to prevent exposure to unacceptable levels of risk (e.g. vapour proof walls, water filtering systems, or physical barriers). The end goal should always be to make sure that humans in the area are not exposed to a dose of the chemical which will impact their health, and to contain and repair any damage to the environment so the land can safely be returned to use.
Environmental Management in Oil and Gas in Alberta
The oil and gas industry in Alberta has come under much criticism for its environmental management. There are tens of thousands of inactive and abandoned sites awaiting assessment and clean up. Many of these sites are in areas where they have little impact, particularly in the remote northern areas of the province. These sites may have an impact on wildlife habitat which may require management but are unlikely to pose a risk to humans. In central and southern Alberta, most well sites are on agricultural land. Depending on the drilling and construction practices used, most sites are low risk and primarily have an impact on agricultural production. Farmers are expected to be compensated for any loss of production due to a well. Drilling and construction practices have improved greatly over the decades so that most new wells are well managed and present very low risk. Larger facilities with tanks that store large volumes of product have a higher risk of causing contamination, as such, proper precautions should be taken to minimize the damage in the event of a spill such as containment around tanks. Similarly, pipelines that pass through sensitive areas such as crossing rivers should have additional monitoring and failsafe mechanisms in place.
For a small spill site in an area where there are no sensitive species or human activities, natural degradation may be the most efficient use of resources. Rather than dig soil from a clean site to replace the soil at a contaminated site, the net overall environmental impact may be less if the contamination is left in place and monitored over time to make sure the condition is improving and that the risk remains low.
For a large spill site or a site near a sensitive area, the cleanup efforts may span decades and be very resource intensive. One of the worst oil blowouts in Alberta, Atlantic No. 3, occurred 70 years ago near Leduc. The blowout resulted in over a million barrels of oil flowing overland, and while the risks are well managed by restricting the land use and ongoing monitoring, the effects can still be seen in sparse vegetation in the surrounding fields.
Most sites will fall somewhere between these two extremes and should be managed by a qualified professional who can consider all the factors involved.
What does it all mean?
How does this help us determine what we should worry about, and what is overhyped? It is well known that historical practices have left a large backlog of contaminated sites in Alberta, and industry has limited resources to make progress on this backlog. A balanced plan needs to be developed with input from regulators, industry, and public stakeholders to address this backlog, and to triage sites near sensitive areas that may present a higher risk. However, the risk presented by the typical oil well or pipeline when considered in isolation is generally low.
It is impossible to eliminate all risk from any activity. What is important is that we focus our attention and energy on the most impactful risks.
The 360 team takes a measured approach to evaluating environmental risk with all stakeholders including industry, regulators, and the public, both during project planning and in spill response and spill clean-up scenarios to implement economic, effective, evidence-based solutions. For more information, please contact Veronica Daigle at email@example.com, or at 403-791-1999.