USEPA CERCLA Guidance Documents (Cont.)

Significance: The significance of this handbook lies in the fact that it is a

USACE Engineer Manual which provides guidance for conducting human health

risk assessments at CERCLA and (Resource Conservation and Recovery Act

(RCRA) sites. The document stresses adherence to EPA risk assessment guidance

and also describes the importance of integrating the risk assessment into a larger

risk management framework.

Summary: This handbook "provides the minimum requirements for

developing scopes of work, evaluating Architect-Engineer (A-E) prepared human

health risk assessments, and documenting risk management options for risk

assessors." The guidelines presented in this document are consistent with and

should be considered in addition to "Risk assessment guidance for superfund,

Vol. I: Human health," (USEPA OERR 1989a) and "Data usability for risk

assessments," (USEPA OERR 1992b). Also, the focus of the document is human

health evaluations for Superfund sites (under CERCLA) and RCRA sites (see

Glossary for definition of acronyms). The USACE also applies Department of

Defense (DOD) policies in their human health evaluations.

CERCLA and RCRA integrate risk assessment into hazardous, toxic, and

radioactive waste (HTRW) investigations. The basic components of a human

health risk assessment at superfund sites are data collection and evaluation,

exposure assessment, toxicity assessment, and risk characterization. Under

RCRA, the EPA defers protection of health of onsite workers to OSHA, but a

customer may request an assessment of short-term and long-term risks associated

with a RCRA site. The authors of this document state that HTRW risk

assessments should present a range of exposures to human receptors, and not

assess risk solely based on the "worst case" or the "most exposed individual"

(MEI).

There are four phases of the HTRW data quality design process used to

develop a scope of work for a risk assessment.

a. Phase I is the development of a site strategy, which includes "customer

communication of needs and understanding the regulatory requirements/

basis for making site decisions" and the involvement of appropriate

project personnel.

b. In Phase II of the data quality design process, data needs are determined.

The output from Phase II is a scope of work and a description of these

data needs.

c. Phase III is where data collection options are identified, assembled, and

presented.

d. In Phase IV, where the data collection program is selected DQOs are

assigned. Uncertainties, cost/benefits, and a schedule associated with data

collection are presented, as well.

CERCLA and RCRA are functionally equivalent in regard to risk assessment

requirements. The project phases for a site investigation are similar and the

A13

Appendix A Summary of Federal, State, and Regional Guidance