February 18, 1997

Disposal costs for dry radioactive waste generated in Northwestern University laboratories have risen to an all-time high, according to Todd Leasia, director of the Office for Research Safety (ORS). "In 1978 we paid $2.82 for each cubic foot of waste; today, due to regulatory pressures and market forces, we are forced to pay $231.27 per cubic foot." The bill for shipping seven 55-gallon drums of laboratory trash last December--contaminated primarily with H-3 and C-14--came to over $12,000, "far exceeding the original purchase price of the radioactive materials," according to Leasia. And that cost "did not include the labor required to manage the material on campus."

ADCO Services, Inc., the firm that picks up and transports the University's dry wastes to the nation's only disposal site at Barnwell, South Carolina, says the cost largely comprises taxes and fees. Just $80.00 (34.6%) of the total is for disposal--paying for the service to pick up and transport the waste and get it into the burial site. Of the remainder, $127.50 (55.1%) is a South Carolina disposal tax, $4.20 (1.8%) is a "capping" fee, and $19.57 (8.5%) is a South Carolina "technology charge." The capping fee is a fee placed in a site closure fund South Carolina will hold in trust until the site closes. Northwestern ships liquid scintillation solvent wastes to another site for incineration, also a costly and controversial disposal method.

What can generators do to control volumes and costs? Most importantly, control volume at the source, according to Leasia. "The long half-life isotopes--H-3 and C-14--are the main culprits. Minimize your radiation work area and disposable equipment. If something is not contaminated, don't throw it into the radwaste drum," he cautions. "Monitor your work area and gloves frequently and carefully, using a wipe test and scintillation counting for H-3. If you find contamination, then dispose of it properly, by all means. But you don't need to put all the bench paper in the drum if just a spot is contaminated. Be conservative, but don't go overboard about it" is his advice.

Radwaste segregation is essential because the University can store for decay all radionuclides with half-lives less than 90 days such as P-32, S-35, and I-125. "We have about 900 cubic feet in storage at any given time," says Leasia, "equivalent to savings of over $200,000. Laboratories must be careful to separate their wastes according to the radwaste guidelines in order to continue realizing these savings."

Other suggested strategies are using mini-vials instead of the standard 20-ml. vials, using washable work area protectors such as trays, and substituting non-radioactive methods for radioactive ones. A large number of colorimetric and chemoluminescent assays now are available.

"The bottom line is that these high costs take resources away from the institution that could better be used elsewhere," says Leasia. "In large measure they are preventable, and we hope everyone will do their part to control them."