Pepper Christopher B, Rainwater Thomas R, Platt Steven G, Dever Jennifer A, Anderson Todd A, McMurry Scott T
The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Box 41163, Lubbock, Texas 79409-1163, USA.
J Wildl Dis. 2004 Jul;40(3):493-500. doi: 10.7589/0090-3558-40.3.493.
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.
最近的研究探讨了绒膜尿囊膜（CAM）作为卵生野生动物环境污染物暴露的非致死、非侵入性指标的效用。绒膜尿囊膜是一种高度血管化的胚外膜，在胚胎发育过程中作为呼吸、营养物质运输和废物储存的场所。孵化后，绒膜尿囊膜通常与蛋壳一起丢弃，可用于化学残留分析。绒膜尿囊膜已成功用于检测多种鸟类和爬行动物的污染物暴露情况并预测化学物质浓度。在本研究中，我们检测了来自伯利兹北部的莫雷莱鳄（Crocodylus moreletii）卵的绒膜尿囊膜中的有机氯（OC）农药浓度。在鳄鱼的绒膜尿囊膜中检测到多种有机氯，包括艾氏剂、狄氏剂、异狄氏剂、滴滴涕、二氯二苯二氯乙烷、二氯二苯二氯乙烯（DDE）、七氯、林丹和甲氧滴滴涕。绒膜尿囊膜中有机氯化合物的数量和浓度各不相同。检测到的最普遍污染物是DDE，69%的绒膜尿囊膜中含有该物质，浓度范围为十亿分之0.3（ppb）至17.0 ppb。鳄鱼绒膜尿囊膜中的有机氯负荷证实了卵受到污染，并表明胚胎和母体雌性受到了暴露。这些结果进一步支持将绒膜尿囊膜用作卵生野生动物有机氯暴露的定性指标。这种采样技术在野外的有效性将取决于与绒膜尿囊膜采集相关的后勤保障和成本，以及野生动物物种的特定生活史特征。
