Alaska

Alaska

The Alaska Department of Environmental Conservation, Contaminated Sites

and Remediation, is currently working on a guidance document that addresses

human health and ecological risk assessment. Public comments on the draft of the

document have been received and a second draft of the document was due in

December 1997. The draft of the document is currently available on the Internet

at:

www.state.ak.us/local/akpages/env.conserv/dspar/csites/tp.htm

California

Document: "Guidance for ecological risk assessment at hazardous waste sites

and permitted facilities, Part A: Overview and Part B: Scoping assessment," (CA

DTSC 1996).

Summary: Part A - The Human and Ecological Risk Division, Department of

Toxic Substances Control (DTSC) within the California Environmental Protection

Agency wrote this guidance. It is a tiered approach to ecological risk assessment

and provides a framework and conceptual model for assessing impact of

chemicals to biota. The document also provides guidance for estimating threshold

concentrations for each chemical of concern and for incorporating the findings

from the ecological risk assessment in remedial, permitting, or control actions.

There are three phases in this risk assessment framework.

a. Phase I is a scoping assessment to predict potential chemicals and

receptors of concern and exposure pathways, develop a site conceptual

model, and identify any further work that is needed. The authors assume

in their risk assessment that individual or population level effects have an

impact at higher levels (e.g. communities or ecosystems), unless there is

evidence to the contrary.

b. Phase II of the assessment is a "validation study" which involves

sampling and analysis of data to refine the Phase I assessment of risk to

biota. If the assessor decides to remediate the site at this point, the data

gathered in Phase II can be used to develop remediation goals.

c. A Phase III "impact assessment" further investigates the risk to biota at a

particular site. In this step, the severity and extent of ecological impact(s),

including remediation impacts, are considered. This information is used to

help the risk manager decide upon a remediation alternative.

Part B - Part B of California's state guidance for ecological risk assessment

explains the Phase I scoping assessment in detail. The purpose of Phase I is to

identify potential receptors, chemicals of concern, and complete exposure

pathways. A list of chemicals of concern can be developed using the site-specific

history of use of the site or using laboratory testing of media. The former is more

commonly used in the Phase I assessment. The assessor must justify the inclusion

or exclusion of chemicals of concern in the risk assessment and consider the

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Appendix A Summary of Federal, State, and Regional Guidance