The Hill News

President Obama released a statement Sunday praising the "final termination" of the blown out oil well that caused an estimated 4.9 million barrels of oil to leak into the Gulf of Mexico five months ago.

He emphasized that he remains "committed to doing everything possible to make sure the Gulf Coast recovers fully from this disaster."

Crews recently finished pumping concrete into the bottom of the Macondo well â€" a final step to prevent further leaking.

"My administration will see our communities, our businesses and our fragile ecosystems through this difficult time," Obama's statement read.

Officials meanwhile have continued to remind the public that challenges lay ahead in restoring the Gulf Coast and its environment to pre-spill conditions.

Rear Adm. Paul Zukunft of the U.S. Coast Guard, who is overseeing cleanup efforts, appeared on CNN Sunday.

"We still have over 600 miles of shoreline from Flor! ida to Louisiana that have been impacted," he said, after acknowledging that some areas have been reopened. "In fact, today I have over 25,000 people out there doing very intense, in high heat conditions, cleanup along those 600 miles."

Zukunft assured viewers that his team is rigorously testing marine life in the area affected by the spill, and that seafood coming out of the Gulf is "the most tested food anywhere in the world, right now."

He also described the processes whereby scientists are sampling ocean sediment at depths as great as 5,000 feet.

"What we're finding are areas in the parts per million, which would not be detectible by the naked eye if it was to be placed in a glass of water, but there's still a presence of oil," he said. "I don't want to diminish the fact that there is residual left from a spill of this magnitude."