OGJ Washington Editor
WASHINGTON, DC, Sept. 28 -- More research into the long-term effects of chemical dispersants is needed despite their apparently successful use in fighting the massive oil spill from BP PLC’s Macondo well in the Gulf of Mexico, US Environmental Protection Agency Administrator Lisa P. Jackson said on Sept. 27.
“We were in a position with no perfect solution,” Jackson told US President Barack Obama’s independent commission investigating the spill and its implications for US offshore oil and gas policy. “Preventing the oil from reaching the shoreline was the No. 1 goal. Still, we must learn from our experience with this tragic event. I am fully committed to revisiting the regulations surrounding EPA’s response, particularly regarding dispersant registration under the National Contingency Plan.”
Dispersant research so far has focused mostly on immediate effects and not long-term impacts, according to Nancy E. Kinnear, co-director of the Coastal Response Research Center at the University of New Hampshire. “Very little is known about chronic toxicity, biodegradability, and other consequences,” she testified.
Initial conclusions show that no combination of resources can fully contain a spill the size of what leaked from the Macondo well, that mechanical recovery is preferable but not always possible the sort of high seas and winds which occurred once these leaks began, and using dispersants was preferable to letting crude oil migrate into sensitive habitats, Kinnear said.
“Dispersants can have a role in responding to a massive offshore spill when climate conditions prevent a strong mechanical response,” she said. “There is a pressing need for independent R&D funded through a rigorous grants process to evaluate the long-term impacts of spilled oil in a variety of environments. We should also evaluate impacts under realistic scenarios.”
Specifically, she said protocols need to be developed to evaluate risks in using dispersants. “First, we need to start using relevant species. We need to think about the relative life stages, which is why assessing risks and keeping it going through the spill is so important,” Kinnear said. “The other thing is that when we do these tests, we tend to look at 96-hr exposures. That’s the standard, but it may not apply if we look harder at acute and chronic toxicity.”
Jackson noted that from the response’s early stages, EPA recognized the need to be vigilant and cautious with the use of dispersants, which it is why, along with the US Coast Guard, it ordered BP to limit its use and volume of the chemicals which are designed to break up spilled crude.
“Specifically, EPA and the Coast Guard issued a directive on May 26 instructing BP to significantly scale back the subsurface use of dispersants to only what was needed to be effective, and to halt use of surface dispersants unless conditions on the ground limited the use of other mechanical means,” she told the commission. BP’s use of dispersants fell 75% from their peak levels after the directive was issued, and while some days showed increases, “the significant decreasing trend line was undeniable,” Jackson said.
EPA knew, based on previous surface dispersant applications, that they were generally less toxic than crude, they decreased the risks to the shorelines and to organisms on the water’s surface, and they biodegraded over weeks or days instead of years as oil does, she noted. “However, all the potential long-term effects of the dispersant application on aquatic life, and the unprecedented volume applied in this response—almost 1.8 million gal—certainly warranted caution,” she said.
BP initially asked EPA on Apr. 30 to use dispersants in a novel manner—underwater, at the leak’s source, Jackson told the commission. “The goal of this approach was to break up and degrade the oil before it reached the water’s surface and came closer to our shorelines, our estuaries, and our marine nurseries,” she said.
Steps to approval
Since this approach had never been tried, Jackson said that EPA asked BP to provide specific scientific data proving that such an application would actually be effective. Once it determined that the process was working, EPA then ordered BP to implement a rigorous monitoring system and track measurable environmental impacts by monitoring dissolved oxygen and toxicity, she said. It conditionally approved BP’s request on May 14 after making clear to the company that EPA reserved the right to withdraw its approval if environmental impacts outweighed benefits of dispersing the oil.
USCG approval of the subsea application was based on conditions resulting from only have the dispersant option on some days, combined with trying to secure the source of the crude oil release, according to Rear Adm. Mary E. Landry from the US Department of Homeland Security agency’s eight district in New Orleans. When we approved the subsea injection, we felt there could be a reduction in the amount of dispersants used,” she told the commission. “In the final weeks of May, trying to secure the source was critical for the workers’ health and mitigating the impacts on the shoreline.”
Landry said she was aware of the obligations imposed on BP by requiring it to ask daily for permission to use the dispersants, but added: “We had an overall goal of reducing the amounts used and accomplished this over time.”
“The good news is that we did not see significant short-term environmental impacts of using dispersants,” Jackson said. “We did not, and continue to not see, diminished levels of dissolved oxygen. This is a good indicator of overall aquatic health and we saw normal levels in testing near the rig site, where subsurface dispersants were applied. We also saw no significant toxic effects on rotifers, which are sensitive organisms that act as the ‘canary in the coal mine’ for water health.”
Water monitoring continues to indicate that dispersants have not been found in waters on or near the shoreline, she continued. Of more than 2,000 samples generated by the National Oceanic and Atmospheric Administration and nearly 1,200 generated by EPA, Jackson said that only two were above the method detection limit but well below health limits. “While these detections were likely caused by problems with the testing devices, they were immediately investigated and the areas re-sampled,” she said. “In both cases, follow-up testing indicated a ‘nondetection’ of dispersant.”
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