| Abstract: |
Differences in genetic susceptibility to hazardous chemicals affect
individuals of both human and nonhuman populations. In both cases,
differences in response to chemicals or general ill health result as
a function of these differences in genetic susceptibility. However,
ecological systems are a compilation of hundreds or even thousands of
different species, resulting in structural and functional
characteristics that are themselves affected by differences in
susceptibility. Although individual and population differences in
susceptibility to hazardous chemicals underlie effects at the
community and the ecosystem level, they do not account for all
differences. I propose a two-tiered approach to evaluating
susceptibility to ecological systems: a general susceptibility as a
function of ecosystem type (based on structure and function of that
system) and a differential in susceptibility within broad ecosystem
types as a function of biotic and abiotic factors. In terrestrial
ecosystems, the two factors that most affect overall susceptibility
are species diversity and hydrology; evaluation of the effects of
hazardous chemicals involves measuring species diversity and water
movement. This same methodological approach can be applied to aquatic
ecosystems and to highly altered ecosystems such as agriculture,
forestry, fisheries, and urbanization. |