Demonstrating ecological receptor health at contaminated sites with wild rodent sperm parameters.

Consistently at Superfund and other contaminated terrestrial sites, ecological receptors have been chemically exposed for multiple decades by the time risk assessments are conducted. Given that numerous generations of the receptors have lived through the contaminated site condition by the present day, a paradigm shift from risk assessment, where the potential for health effects are forecasted, to a direct, health status assessment scheme for the site-exposed receptor, would seem to be most appropriate. We applied the only such existing direct health status assessment method, Rodent Sperm Analysis (RSA), with small rodents trapped at contaminated sites and at matched noncontaminated reference locations. Reproductive health, ecological risk assessment's endpoint of greatest concern, is targeted with RSA by comparing the sperm parameters of count, motility, and morphology, for each of which it is known how much of a change from a control condition signifies compromised reproductive capability. Given that sperm parameter thresholds were not exceeded in maximally exposed receptors, the data suggest that in the general case, contaminated terrestrial sites do not need cleanups to afford health protection to ecological species, and particularly the larger, wider-ranging, higher trophic level species. Our findings suggest that RSA has the ability to consistently discriminate between clean and contaminated sites, and that the method can allow for as definitive determinations of terrestrial ecological receptor health as are possible, thereby facilitating early site clean-up decisions.