This is a brief description of studies that exemplify the methods and approaches that have been developed and used by Oak Ridge National Laboratory (ORNL) researchers in conducting integrated assessments. See the complete list of Integrated Assessment Briefs to find out more about ORNL's efforts in integrated assessment. Contact Mike Farrell (farrellmp@ornl.gov) for more information.

Epidemiological Assessment of an Endangered Species


Conceptual model of the exposure of the San Joaquin kit fox to contaminants.

Is exposure to toxic chemicals responsible for the observed decline in San Joaquin kit fox abundance on the Elk Hills Navel Petroleum Reserve?

The fur of kit foxes, native soil, and contaminated materials were analyzed. Metals in the fox fur were, in general, not elevated relative to reference sites. Some metals that were associated with oil development wastes (arsenic, barium, and vanadium) were elevated in the kit fox fur on the oil field but not reference sites.

Concentrations of these and other elements were not correlated with native soil concentrations. Only arsenic achieved levels that were associated with toxicity in studies of laboratory test species. However, these elevated concentrations occurred in only 1/200 foxes, too few to account for the precipitous decline.

Demographic analysis indicated that the decline was associated with the poor survival of foxes in their first year. The hypothesis that the population decline was because of a drought-related decline in habitat quality rather than toxicity has been supported by a recent rebound in the population following wet years.

Suter, G. W., A. E. Rosen, J. J. Beauchamp, and T. T. Kato. 1992. Results of analyses of fur samples from the San Joaquin kit fox, and associated soil and water samples from the Navel Petroleum Reserve No. 1, Tupman, California. ORNL/TM-12244. Oak Ridge National Laboratory, Oak Ridge, Tenn.


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Integrated Assessment Briefs. 1995. ORNL/M-4227. Oak Ridge National Laboratory, Oak Ridge, TN.