Failures and Successes with Remediation
by Michael King
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CC - Lessons Learned from Past Oil Spills
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Brittany, France 1978 Amoco Cadiz Oil Spill
The largest oil spill of its kind to that date due to gale conditions – 1.6 million barrels of crude oil and 4,000 tons of fuel oil. The oil slick was 12 miles (19 km) long and affected approximately 200 miles (320 km) of coastline. (In comparison, the Exxon Valdez oil spill affected over 1,100 miles of coast line.)
Oil recovery efforts yielded no more than 20,000 tons of crude, the rest was left for cleanup crews and the forces of Mother Nature.
Oil descended into the sand on several beaches to a depth of 20 inches (510 mm) and affected the beaches of 76 coastline communities.
Interestingly, the oil presence on the rocky shores receiving moderate to high wave action was gone within only a few weeks.
Areas more sheltered from the waves of the ocean held onto an asphalt-like crust for several years.
At the time, the Amoco Cadiz oil spill was considered the most devastating to marine life ever recorded from an oil spill. Losses included 20,000 birds, 9,000 tons of oysters and millions of bottom dwelling sea life. (Over 250,000 birds died in the aftermath of the Exxon Valdez oil spill.)
Pressure washing the rocky coast caused additional damage to the ecology, as did the complete removal of gravel along certain beach heads in an attempt to lower the ground level and reduce the size of the beach. The downside of this excavation effort is that it also resulted in additional erosion of the remaining nearby land.
This was the first oil spill in which even the estuary coves and tidal rivers were contaminated with oil.
Due to the size of the spill, chemical detergents and dispersants were applied to only selected sections (to conserve on costs). The vast majority of the damaged areas were left to forces of Nature to clean up.
Fortunately, the Amoco Cadiz spill is also one of the most studied oil spills in history, so there is much that we have learned from this spill that would apply to most other spills. Comparisons with the Valdez spill have added to this bank of knowledge. Here is a brief summary:
Lessons Learned:
1. Results from the studies revealed that the areas affected by the spill that received no detergents or dispersants had fully recovered 5 years later.
2. To this day, 32 years later, the areas treated with detergents or dispersants have still not recovered. (This is due to the toxic nature of the chemicals which also reduce the size of the indiginous microbial populations and marine life that would otherwise become part of the cleanup effort.)
3. According to Terry Hazen, a PhD micro-biologist, when an oil spill occurs, nature goes to work multiplying thousands of varieties of oil degrading bacteria. Local concentrations of these bacteria, suited precisely to the developing situation, are seen to increase over 100,000 times normal levels. We are now seeing this phenomena take place in the Gulf of Mexico.
4. "...1 gram of soil typically contains 1 million to 19 billion microbial cells representing about 4,000 to 10,000 species..." (Torsvik) et al., 1990). This indicates the complexity and genius of Mother Nature.
5. If oil is contained within the ocean waters, it will eventually be broken down by these naturally-occurring microbes.
6. When oil is digested by microbes it is converted into a food for the marine life (oil digested converts into an edible fatty acid, carbon dioxide and water).
7. When land based oil is digested by fungi (mushrooms) it become a fertilizer for the soil.
8. Chemical attempts to dissolve and disperse the oil (due to their extreme toxicity), devastates both the marine life and the microbes necessary to digest the oil.
9. When chemical methods are used, fishermen loose their livelihood in that area for decades to come. (The use of Corexit 9527A Dispersant was responsible for the collapse of the herring industry in Alaska after the Exxon Valdez oil spill.)
10. When natural biological methods are used to clean up oil spills, marine life flourishes causing a doubling in production.
11. When high pressure water techniques are used to remove oil from the coastline rocks, the indigenous plankton and algae (an important part of the food chain), and the microbial life (bacteria and fungi used by Nature to remediate pollution) are also destroyed.
12. One of the greatest lessons learned from actual bioremediation attempts during the Exxon Valdez clean up, is that adding nitrogen fertilizers to the waters in an effort to feed, and therefore increase, the microbial populations, while partially successful, resulted in a decrease in available oxygen for marine life (being used up by the microbes themselves). Lower oxygen levels produce a dead zone of marine life.
13. Therefore nutrients and oil eating microbes, if held together in contact with the oil, but unavailable for dispersal into the ocean water body (where it can overfeed algae and other sea life) is an essential remediation component.
14. Any remediation effort related to a body of water must be effective in 5 basic areas and must preserve as much marine life as possible:
- Shoreline and water inlets,
- Beaches to the depth of the saturated soil level
- Layers of oil and chemicals on the water surface,
- Oil and chemicals on the bottom of the ocean,
- Oil and chemicals in the mid body of the ocean.
Is there a way to address all of the above effectively and repopulate the marine life at the same time?
Stay tuned for next week's call where we will discuss
The Essential Components of an Effective Bioremediation Solution (whether in the Gulf, your local environment, or in your own backyard).
Many blessings of health and success,
Enjoy the simple gifts from Life!
