T3 AM Ecological Risk Assessment (Part 2)
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in Ballroom 3

(POL-1117-320605) A preliminary ecological risk assessment for pesticide use in Talamanca, Costa Rica.

Polidoro, B.^{1, 3}, Morra, M.¹, Castillo, L.E.², Somarriba, E.³, ¹ University of Idaho, Moscow, Idaho, USA³ Centro Agronomico Tropical de Investigacion y Ensenanza (CATIE), Turrialba, Costa Rica² Universidad Nacional, Heredia, Costa Rica

ABSTRACT- Among the most important research priorities identified in tropical ecotoxicology is the need for risk assessment models specific to pesticide fate and toxicity in tropical watersheds. In the Talamanca region of Costa Rica, pesticides are intensively applied to produce export-quality plantains and bananas. Based on the US EPA's ecological risk assessment paradigm, preliminary results from collaborative interdisciplinary and interagency studies on principal exposure pathways, agrochemical environmental fate, and biological effect of exposure are presented. In this region of Costa Rica, significant human and ecological exposure primarily occurs in the absence of regulatory infrastructure or from the lack of knowledge of safe-handling practices. As pesticides generally dissipate and degrade more quickly in tropical regions, the use of passive samplers (SPMDs and POCIS) have proved to be invaluable environmental sampling tools in this tropical ecosystem. However, specific challenges remain in managing and estimating the biological effect of pesticides in tropical environments. The lack of extensive tropical species toxicity data combined with the high biodiversity and complex species interactions found in tropical ecosystems do not allow for easy integration of available toxicity datasets. Similarly, environmental fate models developed for use in temperate zones must be modified to account for different application technologies as well as tropical climatic effects on pesticide dissipation and degradation. Several deterministic and probabilistic risk models for integration of environmental fate and biological effect data are discussed for their suitability and adaptability in tropical regions.

Key words: tropical modeling, passive samplers, pesticides