Pesticides in blood from spectacled caiman (Caiman crocodilus) downstream of banana plantations in Costa Rica.

Spectacled caiman (Caiman crocodilus) are fish-eating crocodilians that inhabit freshwater habitat in tropical regions of the Americas. To assess the exposure of caiman to pesticides from banana plantations, the authors collected whole blood samples (30 mL) from 14 adult caiman that were captured in the North Atlantic region of Costa Rica. Blood samples were analyzed for 70 legacy- and current-use pesticides and breakdown products using newly developed ultra-trace, high-resolution mass spectrometry (HRMS). Caiman accumulated pesticides ranked by concentration as dieldrin > permethrin > mirex > 4,4'-DDE > alpha-endosulfan > heptachlor epoxide > oxychlordane > heptachlor > cypermethrin. Caiman within the high-intensity banana crop watershed of Rio Suerte had higher pesticide burdens relative to other more remote locations (F = 12.79; p = 0.00). Pesticide concentration decreased with distance from upstream banana plantations in this river system (F = 20.76; p = 0.00). Caiman body condition was negatively correlated with total pesticide concentrations (F = 6.23; p = 0.02) and with proximity to banana plantations (F = 5.05; p = 0.04). This suggests that either pesticides elicited toxic effects in caiman, resulting in diminished overall health, or that the quantity or quality of their prey was reduced by pesticides downstream of plantation waterways. The authors' results indicate that pesticide use in banana plantations is impacting a high trophic level species inhabiting one of the most important wilderness areas in Costa Rica (Tortuguero National Park).