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[Protecting the Environment 97]

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New approach to ecological risk assessment

By DENISE CLIFFORD
Department of Ecology

When faced with cleaning up contaminated property, selecting a remedy that protects people's health and the environment is key to the cleanup process.

Bald eagles

Bald eagles near Hood Canal have reproductive problems because of exposure to PCBs. Ecological risk assessments could help protect animals from similar situations in the future.



Washington's cleanup law bases cleanup methods on human-health standards to assure cleanups protect people's health. However, these standards are not always equally protective of the environment.

The state Department of Ecology has not had a consistent approach for dealing with assessing ecological risk at a cleanup site. This has created uncertainty and confusion about the requirements for ecological risk assessments for people conducting cleanups.

Most of the time, when sites are cleaned up to human-health standards, the environment is protected as well. However, there can be circumstances that make plant and animal species more susceptible than people to the toxic effects of contaminants, said Nigel Blakely, a biologist with the Department of Ecology.

People are often exposed to contaminants differently -- and less frequently -- than plants and animals. That means the level of risk is different for plants and animals than it is for humans.

Evaluating the risks to plants and animals at some sites could lead to different remedies to ensure protectiveness, Blakely said.

For example, recent studies show that bald eagles feeding and nesting near Hood Canal are suffering reproductive problems as a result of exposure to polychlorinated biphenyls (PCBs). If a source of PCB contamination in Hood Canal was identified and a cleanup was happening, we would need to look at the risk to eagles from exposure in addition to the human-health based standards that protect people who may be exposed, Blakely said.

Blakely is working with a team of scientists, industry representatives and cleanup professionals to develop consensus-based ecological cleanup standards for soil contamination, as well as a three-tiered approach to use when deciding whether an ecological risk assessment is needed.

Ecological risk assessments will not be required for every site, Blakely said. The three-tiered approach will help screen which sites do and which sites don't.

The first tier involves completing a simple checklist about site conditions. If the checklist shows that the site conditions do not warrant an ecological risk assessment, then the liable party gets an off-ramp from this path of the cleanup process.

If more information is needed, then the party moves into Tier II for the next step of the screening process. If the site is ecologically sensitive, then the liable party must automatically move to Tier III.

In the Tier II stage, liable parties need to provide more detailed information about the site, the contaminants and the species or "ecological receptors" potentially exposed. Tier II also has off-ramps. For example, if the liable party can demonstrate that the soil contamination does not present a significant threat to terrestrial species (and there is no contamination to surface water, sediments or wetlands at the site), then they can get off the ecological risk assessment path. In this case, institutional controls may be needed to ensure cleanup is protective.

Tier III of the process is intended for ecologically-sensitive areas. The approach is conservative, while still affording flexibility and a streamlined process for conducting the assessment. The Department of Ecology and the liable party can work together to decide on site-specific objectives, methods to be used, and how the results from the assessment will be used for remedy selection.

The Tier III approach is similar to that used in other states and by the U.S. Environmental Protection Agency, with some differences based on Ecology's past experience with ecological risk assessments.

Collectively, this work-in-progress is part of the changes to the state Model Toxics Control Act (MTCA) resulting from legislation passed this session. The MTCA Policy Advisory Committee, which studied the state cleanup law for 18 months and provided the recommendations that resulted in legislation, reached consensus agreement on the framework for the three-tiered approach to ecological risk assessments. Ecology is now in the process of amending rules, writing new policies and developing guidance documents in response to the legislation.

To learn more about draft rule language for ecologically-based cleanup standards or the three-tiered screening approach, send e-mail to: nbla461@ecy.wa.gov. After sending an e-mail message, you will be updated on meetings related to the rule-making process.

You also may visit the "Site Cleanup" section of Ecology's Web site .

For more information on the overall rule-making process, call Curtis Dahlgren at Ecology at (360) 407-7187. For technical information on the new ecologically-based cleanup standards, call Nigel Blakely at (360) 407-7189. To volunteer your site for a pilot test of the new standards, call Fred Gardner at (360) 407-7184.


Denise Clifford is the public information officer for the state Department of Ecology's Toxics Cleanup Program.

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