SOLDOTNA (AP) -- A cleanup of some spilled dry-cleaning solvent that has made its way into the Kenai River appears headed for resolution.
The state has called for public comments on a proposal that would chemically treat contaminated groundwater at River Terrace RV Park. That's a privately run fishing spot next to the Sterling Highway bridge in Soldotna.
State officials said the treatment plan would turn the spilled solvent into a benign substance like ethane.
River Terrace owner Gary Hinkle and the state still disagree about the scale and cost of the proposed cleanup, but the state could launch the $1.7 million to $3.7 million effort as early as this fall, said Rich Sundet, DEC project manager.
The state has delayed its plans to widen the narrow highway bridge bordering the RV park while the cleanup plan remains unresolved. The aging two-lane Kenai River crossing becomes a bottleneck each summer. It backs up traffic into the four-lane highway leading through Soldotna's downtown.
The contaminants are believed to have been dumped into the dirt behind a dry cleaning shop that closed in 1988. The shop now houses a fish processing store at the edge of the RV park.
The solvent soaked into the soil. Some was swept along by groundwater toward the river, and some washed toward the nearby highway.
The substance is considered highly toxic to fish and waterborne insects. Traces have been detected in river sediments at levels that could be toxic to small organisms, the DEC said.
But Sundet said if the cleanup blocks any more contamination from reaching the river's sediments, then the existing contamination should break down and dissipate because the solvent is volatile.
Pockets of contamination probably still lurk under the building but the cost of removing the entire structure to get at the source has been judged too high, Sundet said.
''Even if we did massive soil removal, there'd still be some residue going to the highway or toward the river,'' Sundet told the Anchorage Daily News. ''You'd probably have to put in some sort of groundwater treatment system, anyway.''
This type of hydrogen injection has worked in the Lower 48, but the DEC wants to find out how it fares in Alaska, where groundwater temperatures are 20- to 40 degrees colder.
The agency has a backup plan, Sundet said. It involves sinking a curtain of iron shavings that filter out the contamination.
Cleanup at the site began in 1997 when soil was excavated and treated.
Hinkle has owned the property since 1974. The River Terrace contamination first became known in 1992, when a citizen complaint tipped off the DEC that leaking barrels were stored behind the building.
The agency asked Hinkle to remove the drums, which he did promptly.
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