Hopkins William A, Roe John H, Snodgrass Joel W, Staub Brandon P, Jackson Brian P, Congdon Justin D
Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina 29801, USA.
Environ Toxicol Chem. 2002 May;21(5):906-13.
Little currently is known about the accumulation or effects of contaminants on reptiles. To date, most studies examining reptile exposure to trace elements report tissue burdens of field-captured animals, but seldom provide insight into the dose, duration, or mode of exposure involved. For two years, we fed juvenile banded water snakes (Nerodia fasciata) prey items collected from a coal ash-contaminated site that contained elevated levels of As, Cd, Cu, Se, Sr, and V. With the exception of Cu, snakes accumulated significant concentrations of elements, usually in a dose-dependent manner. Accumulation varied significantly among liver, kidney, and gonads, and in most cases between sexes. Selenium accumulation was most notable, greatly exceeding established toxicity thresholds for other vertebrates. Despite the high concentrations of pollutants accumulated, snakes exposed to the contaminated diet survived through the study and exhibited normal food consumption, growth, condition factor, overwinter survival and mass loss, metabolic rate, and gonadosomatic index. The results of this study confirm that diet can be a significant route of exposure to trace elements in snakes and indicate that further studies on snakes are warranted to better understand their responses to contaminants.
目前对于污染物在爬行动物体内的积累情况及其影响了解甚少。迄今为止，大多数研究爬行动物接触微量元素情况的报告都只是阐述了野外捕获动物的组织负荷，但很少能深入了解所涉及的剂量、持续时间或接触方式。两年来，我们给幼年带状水蛇（Nerodia fasciata）投喂从一个受煤灰污染的地点采集的猎物，这些猎物含有高浓度的砷、镉、铜、硒、锶和钒。除了铜之外，蛇类积累了大量的元素，通常呈剂量依赖性。肝脏、肾脏和性腺中的积累情况差异显著，而且在大多数情况下，两性之间也存在差异。硒的积累最为显著，大大超过了其他脊椎动物已确定的毒性阈值。尽管积累了高浓度的污染物，但食用受污染食物的蛇在整个研究过程中存活下来，并且表现出正常的食物消耗、生长、条件因子、越冬存活和体重减轻、代谢率以及性腺体指数。这项研究的结果证实，饮食可能是蛇类接触微量元素的一个重要途径，并表明有必要对蛇类进行进一步研究，以更好地了解它们对污染物的反应。
