Pesticides, such as DDT, still vex Tigard rail site


TIGARD - Cleanup of contaminated soil from a former pesticide manufacturer at the proposed site of TriMet's commuter rail station in downtown Tigard has nearly run its course.

In January, the Oregon Department of Environmental Quality gave its OK for use of the property for TriMet's purposes following a three-year effort aimed at minimizing the extent of the pesticide contamination.

But whether the pesticides, including several substances now banned in the United States and throughout the world, have spread to a small nearby wetland continues to draw state concern.

'The thing that has been the biggest issue to us has been the impact to the aquatic receptors' such as birds and insects, said Loren Garner, who is working the case for DEQ.

Starting in the early 1950s and lasting until 1983, the Tigard-based Farmcraft Facility on Commercial Street produced synthetic pesticides, such as DDT, toxaphene, aldrin and dieldrin, that have since been shown to be harmful to aquatic wildlife.

In 1992, following a fire at the plant, pesticide contamination of the soil was identified and targeted for cleanup. Ownership changed hands several times, leading DEQ to ultimately enlist Union Pacific Railroad to financially back the remediation action, according to DEQ records.

Following the railroad's cleaning of the site, the property was transferred to TriMet, which signed an agreement that holds TriMet harmless if additional contamination is found in that area from past activities.

Local controls

The tainted areas around the TriMet station site, including the building itself that now houses the Ballroom Dance Company, have been cleared through efforts that include capping the contaminated areas with pavement and removal of more than 200 tons of soil from the site. But the question is whether the pesticides have traveled via an underground storm-water pipe to a wetland on Burnham Street as early testing suggested.

Also, Garner said the chemical is likely present in a soil of a nearby business at the edge of the agency's test perimeter.

If so, eradicating the pesticides could prove trickier than simply covering the contaminated areas with cement and leaving it alone, Garner said.

'Those do have a little more impact, especially in the food chain. They are a concern to get them nailed down, especially in that wetland environment,' he said. The synthetic pesticides also bioaccumulate over time rather than breaking down, having a greater effect on wildlife the longer they remain in place.

The extent of the pesticide contamination at the wetland, which is located behind Stevens Marine, is relatively unknown. Garner hesitated to give a cost estimate for cleaning the site, though he said it could be anywhere between $100,000 and $200,000.

Stevens Marine created the wetland, a narrow ditch-like strip overgrown with cattails, to offset that business's encroachment on existing wetlands from an earlier expansion.

Garner said the city-planned improvements complicates matters and that the specific action taken to clear out the contaminated areas depends on the final city-selected street design for Burnham Street.

History of use

DDT, an acronym for Dichloro-Diphenyl-Trichloroethane, went through a heyday of sorts as a mosquito repellant and all-around bug slayer in the early to middle 1900s. In fact, the Swiss man who identified it as an easily and cheaply concocted pesticide, Dr. Hermann Mueller, was awarded the Nobel Prize in physiology in 1948 for his discovery.

At the Farmcraft plant, the pesticides were mixed with carriers such as talc powder and diesel fuel, according to the DEQ records.

Questions popped up in the early part of the 1960s regarding the wisdom of mass DDT sprayings, followed by a hard scientific look that showed the chemical was losing its effectiveness on insects and proving increasingly harmful to wildlife, including sweeping DDT poisonings throughout the world. In the United States, where DDT has especially been shown to be harmful to raptors, the chemical was banned in 1973.

DDT's effect on humans is less harmful, the science suggests, though federal regulatory agencies such as the Food and Drug Administration and the Occupational Health and Safety Administration have set limits on human exposure.