IP07 Population-Level Ecological Risk Assessment
B113 & B114
8:00 AM - 12:00 PM, Wednesday
(IP054) A population-level ecological risk assessment for lead-exposed lizards.
Salice, C1, 1 USACHPPM, APG, MD, USA
ABSTRACT- There is growing interest in approaching ecological risk assessment in a population-level context. One challenge to this approach is relating laboratory toxicity data, which is usually based on a fairly short-term exposure, to alterations in life history traits that then impact population-level processes. Here, an approach is described for linking laboratory-derived toxicity data to population-level processes. The method entails developing exposure-effect relationships from published toxicity studies and describing the relationships with percentage-based effect intervals. Once the exposure-effect relationships are established, for a given exposure, the corresponding effect on survival and reproduction can be readily obtained. Any compound-induced changes in survival or reproduction can then be evaluated in a population-level context using population models. To develop and further evaluate this method, an exercise was conducted using the western fence lizard as a receptor in a lead-contaminated habitat. Exposure-effect relationships were developed from toxicity data on this lizard species. Lead concentration in insects from a contaminated habitat was combined with life history information from a number of studies to estimate lead exposure in lizards. A distributional approach was used to account for variation in both life history traits and lead concentrations. Effects on life history parameters were obtained from the derived exposure-effect relationship and the population-level effects of lead exposure were evaluated using the population model. This method shows viable approaches to placing both exposure and toxicity in a population-level context. Moreover, the study serves as a good launch pad for discussions regarding the similarities and differences of probabilistic and population-level risk assessments. Future efforts are aimed at refining and streamlining the overall approach for use in ecological risk assessments.
Key words: probabilistic, ecological risk assessment, population model, population-level