MEC&F Expert Engineers : Elevated concentrations of benzene and other VOCs in groundwater detected near the Union Pacific derailment site in Mosier, Oregon

Monday, July 25, 2016

Elevated concentrations of benzene and other VOCs in groundwater detected near the Union Pacific derailment site in Mosier, Oregon


Mosier Groundwater Contaminated After Oil Train Derailment

by Kate Davidson OPB | Updated: July 21, 2016 9:17 a.m.

 
Emergency crews on June 4, 2016, found an oil sheen on the bank of the Columbia River near the site of an oil train derailment and spill in Mosier, Oregon, the day prior.

Amelia Templeton/OPB

When a Union Pacific oil train derailed and burst into fire in Mosier, Oregon, in June, the initial damage was in plain view, as dark smoke billowed into the sky.

Now OPB has learned about invisible damage: elevated concentrations of benzene and other volatile organic compounds in groundwater near the derailment site.

Bob Schwarz, a project manager with Oregon’s Department of Environmental Quality, says Mosier’s drinking water is not at risk, as the closest groundwater drinking wells are uphill from where oil spilled. But he is concerned about wildlife in a nearby wetland. He says cleanup is needed.

“The concentration that we found (of benzene) was 1,800 parts per billion, which is approximately ten times higher than a screening level for what would concern us for animals living in a wetland,” Schwarz told OPB All Things Considered host Kate Davidson.  


Groundwater Contamination in Mosier

Oil spilled from the Union Pacific derailment in June has contaminated groundwater at levels that could harm wildlife, according to DEQ. The chart below shows maximum contaminant levels at a groundwater monitoring well near the derailment, as well as their established risk levels. For example, benzene was measured at 1,800 parts per billion, while the safe threshold for fish exposed to benzene is 130 parts per billion. Officials say area wells used for drinking water are located uphill from the oil spill, and are not at risk of contamination.



Tony Schick, OPB/EarthFix. Source: Oregon Department of Environmental Quality