HIGH LEVELS OF HEAVY METALS IN SCUTES AND EGGS OF MORELET'S CROCODILES (CROCODYLUS MORELETII) FROM NORTHEAST MEXICO

Abstract

We evaluated the concentrations of three heavy metals (cadmium, chromium, lead) in eggs and caudal scutes of nesting female Crocodylus moreletii in El Carpintero Lagoon, Tamaulipas, Mexico, in the months of May to August 2013. Samples were processed and analyzed based on the method of flame atomic absorption spectrophotometry at the Centro de Investigacion and Tecnologia en Saneamiento Ambiental (CITSA). Our results showed the presence of cadmium, chromium, and lead in both caudal scutes and eggs. The three heavy metals showed values in nesting females of 20.3, 5.0, and 28.0 mg kg(-1), respectively. We observed significant differences in levels of cadmium and lead among nests but not with levels of chromium. The variations in heavy metal concentrations in eggs suggest that extrinsic and intrinsic factors simultaneously affect crocodiles during the reproductive season. Our levels were high compared with other species of crocodilians and are above thresholds established by Mexican pollution laws.