Organochlorine pesticides in chorioallantoic membranes of Morelet's crocodile eggs from belize.
Recent studies examined the utility of the chorioallantoic membrane (CAM) as a nonlethal, noninvasive indicator of environmental contaminant exposure in oviparous wildlife. The CAM is a highly vascularized extraembryonic membrane that functions as a site for respiration, nutrient transport, and waste storage during embryonic development. After hatching, the CAM is usually discarded with the eggshell and can be used for chemical residue analysis. Chorioallantoic membranes have been used successfully to examine contaminant exposure and predict chemical concentrations in multiple species of birds and reptiles. In this study, we examined organochlorine (OC) pesticide concentrations in CAMs from eggs of Morelet's crocodiles (Crocodylus moreletii) from northern Belize. Multiple OCs were detected in crocodile CAMs, including aldrin, dieldrin, endrin, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene (DDE), heptachlor, lindane, and methoxychlor. Number and concentrations of OC compounds in CAMs were variable. The most prevalent contaminant detected was DDE, which occurred in 69% of CAMs, with concentrations ranging from 0.3 parts per billion (ppb) to 17.0 ppb. The OC burdens in crocodile CAMs confirm contamination of eggs and suggest exposure in embryos and maternal females. These results further support the use of CAMs as qualitative indicators of OC exposure in oviparous wildlife. The efficacy of this sampling technique in the field will depend on the logistics and cost associated with CAM collection and the specific life history traits of the wildlife species.
The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Box 41163, Lubbock, Texas 79409-1163, USA.
Christopher B
CB
Pepper
Thomas R
TR
Rainwater
Steven G
SG
Platt
Jennifer A
JA
Dever
Todd A
TA
Anderson
Scott T
ST
McMurry
D000489:Alligators and Crocodiles / Q000378:metabolism*; D000818:Animals; D000835:Animals, Wild; D001531:Belize; D049033:Chorioallantoic Membrane / Q000737:chemistry*; D004531:Eggs / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis* / Q000302:isolation & purification / Q000493:pharmacokinetics; D005260:Female; D010573:Pesticide Residues / Q000032:analysis / Q000302:isolation & purification; D010575:Pesticides / Q000032:analysis* / Q000302:isolation & purification / Q000493:pharmacokinetics; D014018:Tissue Distribution
D004785:Environmental Pollutants; D010573:Pesticide Residues; D010575:Pesticides