State officials are advising people to avoid eating all fish caught downstream from a June 24 train derailment near Reed Point, when asphalt and molten sulphur spilled into the Yellowstone River and potentially contaminated wildlife.
The advisory includes all fish caught from the Indian Fort Fishing Access Site near Reed Point to the Highway 212 bridge in Laurel.
The state's Fish Consumption Advisory Board stated in a news release that elevated levels of polycyclic aromatic hydrocarbons (PAHs) — some of which can cause cancer in humans — were found in multiple fish species, warranting the advisory.
The Board consists of representatives from the Montana Department of Public Health & Human Services (DPHHS), the Montana Department of Environmental Quality (DEQ) and Montana Fish, Wildlife & Parks (FWP).
In August, the board issued a similar advisory limited to mountain whitefish. Since then, tests of longnose suckers, shorthead redhorse, rainbow trout brown trout also turned up elevated levels of PAHs.
Officials said they could not confirm the source of the contamination and will conduct further testing and sampling, including further downstream.
Some PAHs occur naturally in the environment, especially in the shale rock common in the Yellowstone River Basin. The contaminants are also found in oil, gas, plastics, and pesticides, which could include the derailment as a possible source.
According to the U.S. Department of Energy, PAHs are commonly released during the paving of asphalt.
During the cleanup, asphalt from the train was found as far downstream as Billings, more than 100 miles from the derailment site.
Specific PAHs found in these fish include naphthalene, found in multiple species, and 1- and 2-methylnapthalene and acenaphthylene found only in mountain whitefish.
Fish were collected 6.5 river miles upstream of the derailment site near Indian Fort FAS, and 6.2 river miles downstream near Holmgren FAS.
The U.S. Environmental Protection Agency and the International Agency for Research on Cancer have classified naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene as possibly cancer-causing in humans.
The other two PAHs that have been detected in fish tissue samples, phenanthrene and acenaphthene, have not been classified as cancer-causing chemicals.
Other health effects from ingesting high levels of PAHs that have been shown in animal studies include effects on the gastrointestinal system, immune system, reproductive system, kidneys and skin. These effects from eating fish have not been recorded in humans.
Click here for more information on PAHs, including the specific PAHs found in the fish tissue samples.
Cleanup crews pulled231,700 tons of asphalt from the river, a little more than half the amount estimated to be spilled when the Twin Bridges railroad bridge collapsed while a Montana Rail Link train was crossing.
The cleanup stopped Aug. 16 when officials determined three or fewer "actionable asphalt areas" within a 10-mile stretch of the river. The cleanup endpoint was 136 miles downstream, just in front of the confluence of the Big Horn River.
