PARENT SESSION
PT6 - Biomonitoring
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P651) Organochlorine Residues in Complete Clutches of Morelet's Crocodile (Crocodylus moreletii) Eggs.

Wu, Ted^*,1,2, Caņas, Jaclyn², Thomas, Rainwater², Platt, Steve³, McMurry, Scott², Anderson, Todd², ¹ University of Alaska at Fairbanks, Fairbanks, AK, USA² The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX, USA³ Wildlife Conservation Society, Bronx, NY, USA

ABSTRACT- Here, seven complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs were obtained in northern Belize and examined for OC pesticide residues. Eggs were extracted using a Dionex 200 Accelerated Solvent Extractor and analyzed by GC/ECD. The primary OC detected, p,p-DDE, was found in every egg analyzed (n = 175). Other OCs detected included p,p-DDT, p,p-DDD, methoxychlor, and aldrin. Concentrations of individual OCs (wet weight) ranged from 4 ppb (ng chemical/g egg) to >0.5 ppm (g chemical/g egg). Total concentration of OCs (sum of all OCs) for one egg collected from a nest at Gold Button Lagoon (GB) reached as high as 0.7 ppm. A statistical evaluation of DDE levels in three complete clutches was used to derive the minimum number of eggs needed from a clutch to accurately determine the mean DDE concentration representative of that clutch. Sample sizes of 8 eggs (80% confidence interval) and 11 eggs (90% confidence level) were determined to yield an accurate estimate of contaminant levels in a full clutch of eggs based on an average standard deviation (0.26 ng/g), average clutch size (n = 20), and acceptable deviation from the mean (± 0.1). The statistically recommended sample size of 11 eggs at t(90%) was successfully tested on four additional clutches.

Key words: complete clutch, dde, crocodylus moreletii, eggs