When talking about oil spills, incidents at sea are commonly focused on because of their scale and the widespread damage that oil presents to ocean life and health. However, oil spills on land are similarly dangerous and need appropriate attention and response to rectify.
Knowing how to clean up oil spills on land without exacerbating or incorrectly resolving the issue is key to protecting the environment from their effects, and giving the land a proper chance to recover.
What makes oil spills dangerous?
Oil spills on land have a variety of adverse effects which can contribute to a chain of further problems if left unresolved.
Oil is famously immiscible with water, which means that the two cannot mix without the help of some other chemical. Oil repels water, though it is still a liquid itself. Oil spills on land, therefore, can soak into soil while preventing water from doing the same.
This can cut plant life off from one of its most basic needs, which is particularly dangerous for crops on agricultural land. Not only does this interfere with water entering the land, but can also contaminate any sources of water nearby and leak into the water table.
Oil—particularly crude oil—contains a wealth of contaminants that can be carried through water and present various health dangers, and a relatively small amount of oil can contaminate an exponentially large amount of water.
Even a ‘medium’ oil spill can constitute hundreds if not thousands of litres of oil escaping into the ground, presenting a huge problem for both the land owners and the wider environment.
Oil spills represent a major threat to animal health, as it can coat animals’ fur and feathers. This is commonly seen on sea birds as a result of marine oil spills. As many animals use their mouths to clean themselves, this oil can then be ingested and cause poisoning. It can also break down furs, destroying an animal’s ability to keep itself warm and protected.
Oil spills on land can ultimately affect the food chain and directly impact human health and the safety of human food sources, particularly in scenarios such as agricultural machinery breakdowns which then cause oil spills directly onto farmland.
Spilled oil is a major source of pollution wherever it occurs, particularly if it’s able to enter the air. Its natural propensity to repel water ensures that it isn’t simply washed away in the rain, and studies have shown that it doesn’t decompose for decades.
Even if an oil spill isn’t presenting any direct threat to the environment or human health, it’s still a problem that needs remediation. Oil-contaminated land can prevent site development and new buildings being made safely. If this contamination is discovered after work has already begun, it can be a big problem (and financial expense) for those responsible.
How are oil spills cleaned up on land?
The initial impacts of oil spills on land can be highly complex to measure, given that oil spilled on materials like soil and gravel will soak down into the ground rather than sit like it would on a solid surface. This can make an oil spill deeper than it is wide, and overall more massive than it first appears.
Additionally, being immiscible with water, oil cannot simply be washed away. A measured and multi-layered approach to cleaning an oil spill on land is necessary to ensure there are no unresolved pockets of contamination and that the land is fully remediated for future use.
Before the cleaning can begin, it’s best to review the site and take stock of any specific features and aspects of the land that might present particular challenges. In the case of an oil spill, this could unveil an unexpected source of contamination or the presence of a hazard that could make the problem worse, such as sources of ignition.
Once the site has been reviewed, then a proper assessment of the case can be made, including the most favourable strategies to remedy the damage and any other courses of action that will need to be taken. In DHI’s case, we use our expertise to assess which materials can be saved from landfill, by being relocating into our network of treatment centres.
There is no single best method to clean up, and finding how to clean up oil spills most effectively is knowing which combination of tools and methods available will achieve full remediation.
While not a method of clean up, per se, cleaning an oil spill on land begins with controlling the problem and ensuring the source is not still active. Righting and removing spilled barrels, turning off any machinery and potential sources of ignition, and determining the full scale of the spill are all actions that may need to be taken before clean up can begin.
Some of the tools available for cleaning up a land-based oil spill include:
Simple and straightforward but effective, absorbent pads have as much a place in soaking up oil from land as they do absorbing liquids around the house. However, absorbent materials developed for oil spills are hygrophobic, which means they won’t absorb water and moisture but will take up hydrocarbons.
This is particularly useful for absorbing a pool of oil without moisture in the ground interfering with the process, which is a concern for materials like soil which can hold a lot of water even days after the most recent rainfall.
Booms are long, thin, sock-like objects that are also designed to absorb oil. However, unlike absorbent pads and rolls, booms are used as barriers to prevent oil spreading farther while clean up is carried out. They can be used on both water and land, and their shape allows them to be articulated in such a way that they can precisely outline the site of a spill.
Absorbent booms designed for use on land often contain dense material to keep them stable and in-place once laid down, making them a reliable barrier for any spread and to keep the problem contained.
It should be noted that for oil spills in soil, the problem will mostly move down and not out. Booms are effective, but the majority of the clean up operation will likely be more concerned with the depth of the spill and not the breadth.
The way in which water and oil repel one another can be used as an advantage in some cases. Water can be used to ‘float’ the oil, if there’s no greater risk in introducing a controlled flood to the area. This can be skimmed or vacuumed from the water’s surface and collected.
Using water is not suitable for every case of an oil spill on land, and it may be that absorbent materials and contaminated land removal are the only feasible ways to remediate an affected site.
What is the most effective way to clean up an oil spill?
The most effective methods for cleaning an oil spill on land depend heavily on the context of the incident. Spills in urban environments, where heavy use of concrete and road surfacing materials prevent easy access to soil beneath, may demand a different approach than an oil spill on agricultural land.
Often, not all of the land itself can be fully cleansed of the oil as is, and contaminated soil will need to be removed for disposal or, if possible, remediation. Whatever the specific courses of action used, a combined approach is ultimately the most effective way to clean up oil spills.
Given the great risk to the environment presented by oil spills, and the fault of human industry in causing them, we cannot overstate the importance of prevention rather than simply focusing on remediation. Having measures in place to prevent oil spills as much as possible, with fallback measures and plans in place for the event of a spill, will already be doing most of the work to ensure land stays clean and free from contamination.
Regardless, however bad an oil spill on land, the situation is never irredeemable. With the right knowledge and experience, there is always something to be done in terms of remediation and land recovery, even if an unfortunate proportion of the land needs to be disposed of.
How to respond to an oil spill
If you suffer an oil spill on land that needs remediation, call a site clearance and land remediation company like DHI Excavations as soon as possible. We’ll take control of the situation and work with you to achieve swift clean up, giving you the best advice and guidance to help manage the incident while we make our way to you.