From The Denver Post (Bruce Finley):
This poses a regulatory dilemma: Is it worse to release benzene into the air or into the water? Colorado Department of Public Health and Environment regulators haven’t decided. “It’s an important balancing act,” spokesman Warren Smith said. “We want to protect both as best we can.”
The latest test data show benzene concentrations in the South Platte River remain more than 30 times higher than the federal drinking-water standard of 5 parts per billion. In an attempt to reduce those levels, a diesel-powered pump pulls 500 gallons a minute out of Sand Creek and returns it to the stream in an aerial arc. The action is designed to free the benzene from the water before it lands back in the stream…
The fountain aeration — a temporary fix — is part of Suncor’s overall cleanup efforts following the discovery in November of an underground plume of hydrocarbon material from the refinery oozing into the water from creek banks.
Suncor recently completed two underground walls designed to intercept toxic material spreading from the refinery. Sump pumps and vacuum systems near the walls are designed to remove liquid hydrocarbons and toxic vapors from contaminated soil. A Suncor environmental contractor’s map, released by CDPHE, shows an underground plume of benzene and other contaminants spreading under the adjacent Metro Wastewater Treatment Plant and nearly reaching the South Platte directly upriver from the confluence with Sand Creek. This plume also is spreading under the open space greenway bicycle corridor toward Interstate 270. Four monitoring wells — a fifth is planned — may help monitor the eastern edge of the plume. Benzene concentrations are low and decreasing at far edges of the plume but reach as high as 10,000 parts per billion (ppb) at the center. Suncor crews have completed a 1,000-foot wall on Metro Wastewater property to shield Sand Creek. They built a 2,100-foot wall at the western edge of Suncor’s property.