Bishop C A, Brooks R J, Carey J H, Ng P, Norstrom R J, Lean D R
Canadian Wildlife Service, Ontario Region, Canada.
J Toxicol Environ Health. 1991 Aug;33(4):521-47. doi: 10.1080/15287399109531539.
Concentrations of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans, organochlorine pesticides, and their metabolites were measured in eggs of the common snapping turtle (Chelydra s.serpentina) collected from four wetlands on the shorelines of Lakes Ontario, and Erie, and one control location in central Ontario, Canada. Snapping turtle eggs from these sites were also artificially incubated to determine hatching success, and incidence of deformities in embryo and hatchling turtles. The hypothesis that elevated incidences of egg death and/or deformities of hatchling turtles would occur in populations with high concentrations of organochlorine contaminants in eggs was tested. The results were elevated using epidemiological criteria. Unhatched eggs and deformities occurred at significantly higher rates in eggs from Lake Ontario wetlands. Two of three sites from Lake Ontario had substantially higher levels of PCBs, dioxins, and furans compared to eggs from Lake Erie and the control site. It could not be shown that contamination of eggs preceded the occurrence of poor development of eggs, although excellent hatching success and low numbers of deformities in eggs from the control site were considered representative of development in healthy eggs. The statistical association between contaminant levels in eggs and poor development of these eggs supported the hypothesis that eggs from sites with the greatest contamination had the highest rates of abnormalities. PCBs were the most strongly associated chemicals, although possible effects due to the presence of other chemicals in eggs was a confounding factor. The deformities and rates of unhatched eggs were similar to those occurring in other vertebrates collected from highly contaminated areas of the Great Lakes. There were several chemicals present in the eggs that can cause similar reproductive effects in other species; therefore a specific chemical effect was not identified. Results were coherent with known statistical and biological information. Theoretical and factual evidence of PCB contamination in wild-caught snapping turtles supported and hypothesis. However, lack of controlled studies of reproductive effects of polychlorinated hydrocarbons upon this species hindered the agreement of all factual and theoretical evidence with the hypothesis.
在从加拿大安大略湖和伊利湖沿岸的四个湿地以及安大略省中部一个对照地点采集的普通鳄龟（Chelydra s.serpentina）的卵中，测量了多氯联苯（PCBs）、二苯并 - p - 二恶英、二苯并呋喃、有机氯农药及其代谢物的浓度。还对这些地点的鳄龟卵进行了人工孵化，以确定孵化成功率以及胚胎和幼龟的畸形发生率。对卵中有机氯污染物浓度高的种群中卵死亡和/或幼龟畸形发生率升高这一假设进行了检验。使用流行病学标准对结果进行了评估。安大略湖湿地的卵中未孵化卵和畸形的发生率显著更高。与伊利湖和对照地点的卵相比，安大略湖三个地点中的两个地点的多氯联苯、二恶英和呋喃水平要高得多。虽然对照地点的卵孵化成功率高且畸形数量少被认为代表健康卵的发育情况，但无法证明卵的污染先于卵发育不良的发生。卵中污染物水平与这些卵发育不良之间的统计关联支持了这样的假设，即污染最严重地点的卵异常发生率最高。多氯联苯是关联最紧密的化学物质，不过卵中其他化学物质的存在可能产生的影响是一个混杂因素。畸形和未孵化卵的发生率与从五大湖高度污染地区采集的其他脊椎动物中出现的情况相似。卵中存在几种能在其他物种中引起类似生殖影响的化学物质；因此未确定具体的化学效应。结果与已知的统计和生物学信息一致。野生捕获的鳄龟中多氯联苯污染的理论和事实证据支持了该假设。然而，缺乏关于多氯代烃对该物种生殖影响的对照研究，阻碍了所有事实和理论证据与该假设的一致性。
