Metals that Drive Health-Based Remedial Decisions for Soils at U.S. Department of Defense Sites

ABSTRACT

This study was undertaken to establish which metals are most likely to drive the risk-based remedial decision-making process at those U.S. Department of Defense (DoD) sites that are affected by metals in site soils. Our approach combined queries of various databases, interviews with U.S. Environmental Protection Agency (USEPA) experts in each Region, and communication with database administrators and DoD personnel. The databases that were used were comprehensive for DoD sites, yet sometimes contained inaccuracies. Metal concentration data for various DoD facilities were screened against established regulatory criteria for both human health and ecological endpoints. Results from this analysis were compared against the information gleaned from the interviews. This preliminary analysis indicates that the five metals that most frequently exceeded risk-based screening criteria for potential human health concerns at DoD sites, in descending order of frequency, are lead, arsenic, cadmium, chromium, and antimony. The metals that most frequently exceeded ecological screening criteria, in order, are lead, cadmium, mercury, zinc, arsenic, chromium, and selenium. Although the majority of USEPA personnel interviewed indicated that human health risk, rather than ecological endpoints, generally drives remedial decision-making, the data indicated that ecological screening thresholds were exceeded more often than human health standards.

Keywords:

• metals in soil
• Department of Defense
• human health risk
• ecological risk
• remedial decision-making.

ACKNOWLEDGMENTS

The Strategic Environmental Research and Development Program (SERDP) is gratefully acknowledged for funding this research. We also thank the contacts at USEPA for providing information on risk assessment activities at DoD sites, the database managers at the various DoD branches for sharing their databases, and the anonymous reviewers for providing helpful comments.

Notes

^a Increased original value by one order of magnitude

^b USEPA (2001)

^c Efroymson et al. (1997)

^d Region IX PRG (USEPA 2000a)

^e U.S. EPA (2000b).

^a For example, lead concentrations exceeded residential screening crtierion at 32% of the sites. For each metal, the receptor with the greatest percentage of sites exceeding criteria is bolded.