A mysterious oil spill on the Potomac River near Washington DC has been spotted. Federal, state and local authorities are as yet investigating the source.

NBC Washington reported the oil sheen to have first been spotted on Monday, Feb. 1, beyond a containment boom where the Roaches Run waters flow under the George Washington Memorial Parkway.

The US Coast Guard surveyed how far the substance had traveled, with the use of a helicopter. They found it could be seen as far down the river as Mount Vernon, Virginia.

Concerned watching commercial jets flying into Reagan Washington National Airport expressed concern about the spill, which could be seen

The oil sheen could be seen on a length spanning eight-miles of the Potomac River near Washington DC. It also extended to Virginia's Roaches Run Waterfowl Sanctuary, which has allegedly been recognized as the place where the oil started becoming visible.

According to a report by NBC Washington, several ducks and a minimum of 21 geese were found to be coated with oil.

The US Coast Guard is set to dye the river to find out the source of the spill. "We want to inform people in an attempt to mitigate concern by the public, who may see the dye in the water and mistake it as something else," Coast Guard Commander Michael Keane was reported as saying in a statement.

Floated barriers and absorbent material has also been put up by the US Coast Guard; but the amount of the substance seems too small to catch any. The absorbent pads and boom seem mostly to be catching dirt.

Samples of oil from the Roaches Run are being tested by the Coast Guard laboratory to try and find out where it is coming from. Samples of oil from the Dominion Virginia Power substation are used to be tested against it, and Dominion is offering cooperation, but there is no evidence that the spill is from its facilities.

UPDATE: The Washington Post has updated its previous report, and has now claimed the oil to be fuel oil with source still unknown.