By ERIC A. HOWALD
Of the Keizertimes
The Oregon Department of Environmental Quality (DEQ) looked at several options for handling contaminated soil at the site of a residential development in Salem before determining that moving it to two abandoned quarries north of Keizer would be the best fit.
The decision boiled down to how the soil could be accessed by the public, said Nancy Sawka, a senior project manager with DEQ. The owners of the Northstar development, Granada Land Company, LLC, proposed several options for dealing with the pesticide-contaminated dirt: moving to a low-lying area of the property and capping it, which would require ongoing monitoring; treating the soil onsite to reduce contamination; excavating it and moving it to a landfill; or moving it to the quarry pits for future continued agricultural use.
Moving it to the quarries was the cheapest option on the board, but it had other benefits, Sawka said.
“Even if the contaminated soil was capped (onsite), there would always be a chance that residents or children could come in contact with the soil by digging or that the soil could be exposed during outdoor projects or subsurface work,” she said.
It would require that every home on the property come with a deed restriction notifying all future owners of the dieldrin contamination (see sidebar: What is dieldrin?). While that might work fine for immediate owners, the likelihood of forgetting over time makes it a problematic solution.
“This can result in people being exposed to contamination in the future, often without knowing about it. Especially for a site like this with contamination over a large area, with many different future land owners, capping and managing soil in place would be very difficult to implement and not as protective as removing it in a controlled manner under DEQ oversight,” Sawka said.
Sawka said the owners did not look at alternative sites for dumping the soil.
Aside from cost, each of the possible solutions was scored on: the effectiveness and protectiveness of the clean-up, the long-term reliability, how difficult or easily the plan could be implemented, any risks associated with performing the actions.
DEQ officials also paid attention to the how the soil would be used in the quarries – for growing hazelnuts. To that end, DEQ consulted the Oregon Department of Agriculture regarding the possibility of the resulting nuts containing dieldrin.
Sawka passed along the following response from ODA officials: “People are primarily exposed to dieldrin when eating certain crops grown in soils where dieldrin was previously used. Crops such as squash, pumpkin, zucchini, and carrots are most apt to uptake dieldrin from the soils. Many crops do not uptake dieldrin or do so at very low rates. Hazelnuts are proposed to be grown at the new location. It’s unlikely that hazelnut (filbert) trees uptake significant levels of dieldrin.”
Moving the dirt through Keizer, and past four schools, drew outcry from those responding during a public comment period about the plan. Sawka does not expect contamination during transport to be a problem and is basing the conclusion on monitoring of the current site while soil was being moved.
“The dust and air was monitored during the preliminary soil excavation activities that were conducted on the east side of the site between August 7 and 15, 2017. Dieldrin was not detected in any of the air samples,” she said.
She added the trucks moving the dirt will remain on graveled temporary roads during loading to minimize dust.
“The trucks will be washed to rinse the exterior as well as lightly wet the soils to help suppress any dust during transport. The soil in the truck will be securely covered with a tarp. After the soil is unloaded at the receiving site, the trucks will be swept clean before returning to the road. Dust suppression will also be done at the site receiving the soil,” Sawka said.
I & E Construction, the main contractor, will also need to have a spill prevention, response and safety plan in place.
Prior to August, DEQ officials had not visited the quarries, but have done so since a meeting with Keizer representatives on July 31. Sawka said no testing was done because it is not required and was not requested by the owners, but the visit was intended to help DEQ better address some comments received during the public comment period.
One of the outstanding conflicts is where the water table begins on the quarry property. According to the property owner the quarries are about 17 feet deep, and well logs from 2005 show workers first struck water at a depth of 17 feet.
“Hydrogeologists and licensed geologists from DEQ reviewed the application for the placement of the soil in the quarry pits and came to the conclusion that there are no potential groundwater impacts because dieldrin is not very soluble and binds tightly to the soil. This is why dieldrin is still present at low levels in the soil on the site and in other agriculture soils in the Willamette Valley even though it was banned. If it were soluble, it would have washed out of the soil and would no longer be present,” said Sawka when asked about the possibility of dieldrin leaching into Keizer’s water supply.
Even with all that in place, it is unlikely that trucks will begin moving through Keizer very soon. One of the quarries contains mapped wetlands and will require permits from the Department of State Lands and the Army Corps of Engineers before it can be filled.