Discovery Guides Areas


Deep Sea Oil Spill Cleanup Techniques: Applicability, Trade-offs and Advantages
(Released August 2010)

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  by Pam Graham  


Key Citations




Cleanup: Chemicals and Microbes


Oil spills kill wildlife and cause ecosystem damage that can last for generations by forcing changes in reproduction and compromising complex food webs.

The impact scientists worry about most in a major spill is more subtle than the presence of oil on feathers or fur. It is the long-term exposure to dispersants and oil that have the potential to trigger dramatic die-offs and population declines. Scientists are not yet able to address these large-scale effects, and will require new methods to monitor and assess the impact of deep, massive leaks far offshore, like the one that resulted from the explosion of the Deepwater Horizon oil rig.

Scientists, volunteers and other responders are, however, prepared to deal with oiled wildlife and shoreline effects, because those are the usual problems. [34] While experts agree on the most viable methods for cleaning oiled wildlife, they disagree about whether rescuing individual animals impacted by a spill is worthwhile. This Discovery Guide bypasses the argument for euthanasia and concentrates on techniques for cleaning and rehabilitating oil-impacted wildlife.

two pelicans
A brown pelican, covered with oil from the BP Deepwater Horizon

The chemicals in oil are toxic and only trained personnel with appropriate protective gear and equipment should handle and treat oiled animals. For the health and safety of rescuers and the animals they are trying to save, the Marine Mammal Health and Stranding Response Program and the Sea Turtle Stranding and Salvage Network urges anyone who finds oiled wildlife to avoid direct contact with the animal and immediately call their Wildlife Hotline or other rescue organization so they can deploy trained wildlife personnel to collect the animal. [35]

When trained professionals respond to such a report, they generally go through a seven-part rescue and treatment process:

  1. Both live and dead wildlife are collected.
  2. Rescues receive a full physical examination.
  3. Rescues are warmed, fed, hydrated and then rested for 48 hours.
  4. Rescues are washed in a series of tubs filled with a mixture of diluted cleaning agent and hot, softened water.
  5. Cleaned animals are then placed in outdoor pools or other appropriate housing for anywhere from three days to several months, depending on the animal's condition.
  6. Rescued animals receive another medical examination and are banded or tagged before released back into a clean habitat.
  7. Released animals receive a post-release assessment, which often entails tagging the animals with radio devices and monitoring them. [36]

Birds are some of the most frequent animals at rescue sites. It was once believed that washing a bird with soap would remove the natural oils from its feathers, causing the bird to lose its insulation and waterproofing, which would lead to its death. But what actually keeps birds waterproof is the position of the feathers, which overlap each other like shingles on a roof to create a covering. Millions of tiny barbs on individual feathers gently interlock to form a flexible seal. Preening is all about aligning feathers to ensure a waterproof and airtight seal that insulates the body for insulation and buoyancy. If the feathers aren't perfectly aligned, the bird will die from exposure. Oil kills birds by matting feathers and separating the intricate barbs, which exposes the bird to temperature extremes.

Oiled birds are initially too traumatized to be washed immediately, but once stabilized, they go through a series of tub washes alternating between baths with a one percent solution of Dawn dishwashing liquid and clean water. The wash time varies depending on the amount of oil and the size of the bird, but on average it takes two people 45 minutes and 300 gallons of water to do a thorough washing. [37]

Machines that wash oiled animals have been available for at least a decade. Manufacturers claim they cut clean-up time by half, reducing a 35- to 45-minute manual washing to just 20 minutes. The speed, however, may come at a cost. Jay Holcomb, executive director of the International Bird Rescue Research Center (IBRRC), told Discovery News that his network of specialists will not use such a machine "as it does not truly clean the birds all the way and is sometimes hurtful to them." While working after the ERIKA oil spill in France, his specialists initially used a machine, with disastrous results. Due to the machine's inability to adapt to individual birds' shapes and sizes, each time the machine was used, wings were injured and many birds died. [38]

Before a bird can be released, it should be able to pass a waterproofing test. That is, it must demonstrate the ability to float and the ability to keep water away from its body. Once a bird passes the test, it is slowly exposed to temperatures comparable to outside weather. Its weight and muscle structure should be average for its species, and it should show no signs of disease. After banding, rehabilitated birds are released early in the day to an appropriate habitat. [39]

Unfortunately, the success rates of bird rehabilitation have been low in past spills. In 1999, when the Maltese tanker ERIKA spilled 31,000 tons of oil in the Bay of Biscay, a major cleaning operation was mounted for the 15,000 oiled sea bird survivors and 2,000 were ultimately released. [40]

Sea Turtles

Sea turtles are vulnerable to oil exposure by many different routes. Several aspects of sea turtle biology make them highly sensitive to chemical insults such as oil, and their natural behavior, including indiscriminate feeding in convergence zones, a lack of avoidance behavior and large pre-dive inhalations, places them at particular risk in oily waters.

turtle splotched with oil
Studies in Gulfport, Mississippi document a dead Kemp's Ridley turtle that washed up on the beach

In addition, many response activities can result in unintended adverse impacts to turtles. Dispersants can interfere with lung function through their detergent effect. In-situ burns require careful surveying for sea turtles before ignition, and even then smoke inhalation can harm the lungs. Additionally, the increased boat traffic during an oil spill cleanup adds increased danger due to collisions with swimming sea turtles. [41]

Oiled sea turtles present a different set of challenges than birds, requiring antibiotic treatment for lung and gastrointestinal damage caused by swimming for long periods of time through oil-saturated waters. When it comes to external recovery, veterinarians often use mayonnaise to help break down the oil in the eyes and other sensitive areas. [42]

Experts agree that hatchlings from sea turtle nesting in the wake of the Deepwater Horizon oil rig explosion are in jeopardy of being completely wiped out by the oil. In response, officials drew up a plan to dig up the approximately 700 nests on Alabama and the Florida panhandle beaches. Translocation of nests on this scale has never been attempted before. Sea turtle biologists have mixed opinions about this plan to relocate thousands of sea turtle eggs over 40 days old. This procedure is very risky to each and every sea turtle embryo, but many experts feel the hatchlings emerging from nests along Mississippi, Alabama, and Florida panhandle beaches will be doomed to oily deaths if they are not moved. Others believe that relocating a species endemic to the area, like Kemp's ridleys to Gulf beaches, away from their natural nesting area, is ecologically unsound. [43]

At the writing of this Discovery Guide, there was no data on the success of this unprecedented relocation effort.

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