Animal rescue teams and government agencies have rushed to Billings, Montana where they are assessing the damage from the Exxonmobil pipeline spill that occurred 2 July in the Yellowstone River, the longest undammed river in the US. Exxonmobil has estimated that up to about 160,000 litres of oil leaked from a ruptured pipeline into the river. But so far, teams haven’t come across any animals in distress.
“We aren’t seeing a lot yet, but that doesn’t mean there may not be some stuff out there,” says Ron Aasheim, chief of communication for the Montana Fish, Wildlife and Parks department in Helena, Montana. “We haven’t had much time to look.”
Dangerously swift currents have hampered assessment efforts, limiting teams’ knowledge of the damage, but so far the short term problems seems to be minimal.
“We haven’t seen any floating fish or anything like that,” says Bob Gibson, “The water is running very high so that means the oil that went into the river could have been carried away very quickly.”
Floods could also have kept birds out of the area during the time of the spill, says Darcie Vallant, director of the Montana Audubon Education Center in Billings.
“We’re in an extreme flood situation, so many of the birds normally around, including pelicans, are not in their usual spots,” she says.
But damage to the ecosystem could be floating just beneath the surface, Gibson told local reporters. Floodwaters have left standing pools of water alongside the river, where oil has accumulated and could affect organisms that live there. Insects and fish that populate those areas could suffer from a lack of food and oxygen.
And once floodwaters recede, any oil left behind could contaminate soil and organisms such as crayfish, worms and insect larvae among other ‘macroinvertebrates’.
From there, says Vallant, “Oil could work its way into fish, then up to species such as river otters that feed on those fish.”
Other animals to watch in the coming weeks for negative impacts include turtles, songbirds, eagles, endangered fish and other animals that call the river home, Vallant adds. Numbers of the American white pelican (Pelecanus erythrorhynchos, pictured) were already reduced last year because of West Nile virus, and could be further reduced if their food supply is affected.
Officials aren’t sure yet what caused the oil spill Saturday in the 30–centimeter crude pipeline running from Silver Tip, Montana to Billings. The pipeline was shut down soon after a drop in pressure was detected. There’s some speculation that floodwaters could have exposed the pipeline to damaging debris, but the investigation will have to wait until the floodwaters recede. For now, oil to the pipeline remains cut off.
Oil has been detected up to 25 miles downstream of the leak, says Gary Pruessing, president of the Exxonmobil Pipeline Company, though it may have gone farther. He says that crews continue to search for oil by plane, and 150-200 people are on the ground cleaning up the spill with absorbent boom and pads. (Exxonmobil has updates on the situation here.)
The spill has renewed opposition from environmental groups to TransCanada Corp’s proposed Keystone Pipeline Expansion Project, which would extend a current pipeline from Alberta, Canada all the way to Texas, going through Montana and under the Yellowstone River.