T2 AM 'Omic' Technologies: Current and Future Application to Environmental Toxicology (Part 1)
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in Ballroom 2

(PER-1118-091610) Does Toxicogenomics Have Any Practical Use? - Assessing Presence and Population Level Impacts of Contaminants.

Perkins, E¹, Steevens, J¹, ¹ U.S. Army Engineer Research and Development Center, Vicksburg, MS, 39180

ABSTRACT- The Department of Defense is responsible for stewardship of more than 25 million acres of land used primarily for military training and testing. Current approaches employed by the military to assess the impact of military training and testing on the environment include more traditional environmental assessment tools within the risk assessment paradigm (e.g., bioassays, chemistry, and surveys). For the most part toxicogenomics has not been utilized within ecological risk assessments and has provided little value in making resource management decisions. While proposed as a screening tool in human health, drug development, and ecological assessments the principle goals of contaminant risk assessment and resource management require strong linkage of toxicogenomic studies to management objectives. In addition to development of screening tools, our laboratory has focused on toxicogenomics as a tool to link molecular level events to individual and population level effects of military unique contaminants (i.e., metals and explosives). These studies have been conducted in the laboratory using a wide variety of species (e.g., rats, quail, fish, soil and aquatic invertebrates) to understand the impact of military contaminants in different environments and scale differences between species for use in cross species extrapolation. A critical component of the effort is to scale whole organism effects (growth, reproduction) that can be quantified and used for population modeling. For example, in linking toxicogenomics to a measured dose of TNT (i.e., tissue residues), we found no correlation between TNT exposure levels and gene expression but a high correlation between expression, tissue residues and lethality in the benthic invertebrate Leptocheirus plumulosus. Similar studies are being conducted with the earthworm Eisenia fetida, and fathead minnow Pimephales promelas with DNT, TNT, and RDX to further understand exposure-dose-effect relationships. Given the likely variability in contaminant dose, biological diversity, and sensitivity, toxicogenomics is limited to its use as a tool within the greater context of improving methods for assessing exposure and ecological effects of contaminants.

Key words: Toxicogenomics, Explosives, Population Assessment