Chapter 4 - Reptiles

Abstract

In addition to analytical deficiencies, information is lacking on the age, size, weight, and sexual condition of samples, all of which are important in assessing the significance of metals in long-lived species of reptiles. Turtles, crocodiles, iguanas, and sea snakes are the most common reptiles encountered in marine waters. No kills of reptile field populations due to metal intoxication have ever been reported. Except for tissue-metal levels in free-ranging reptiles, studies on the ecotoxicology of metals are rare. No studies are available that directly address metal toxicokinetics in marine reptiles impacted by changing abiotic variables such as water temperature, salinity, or pH. In general, aluminum, chromium, and copper burdens are consistently higher in eggshells of marine reptiles when compared to egg contents; however, cadmium, iron, mercury, manganese, and zinc are higher in egg contents. The disease known as green turtle fibropapillomatosis or GTFP is considered a threat to the survival of the green turtle, Chelonia mydas. Anthropogenic contaminants, including metals, were suggested as a possible cause of GTFP. In the absence of credible baseline data for metals in marine reptiles, the authors concluded that metal levels were at or below concentrations considered normal for other animal groups, and that metals played a negligible role in the etiology of GTFP in the green turtles analyzed.