Species-Specific Distribution of Heavy Metals in Tissues and Organs of Loggerhead Turtle (Caretta caretta) and Green Turtle (Chelonia mydas) from Japanese Coastal Waters

Concentrations of heavy metals (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Co and Hg) were determined in tissues and organs of loggerhead (Caretta caretta) and green turtles (Chelonia mydas) collected from Japanese coastal waters, in order to elucidate body distribution and to develop a non-lethal monitoring technique using the carapace. A majority of the metal burdens was present in the muscle, liver, bone and carapace of sea turtles. High Cu concentrations exceeding 10 μg/g wet wt were observed in the liver of these two turtle species. Mean Zn concentrations in fat tissues of loggerhead and green turtles were 94.6 and 51.3 μg/g wet wt respectively, which were about 10-fold higher than those reported in other marine animals. Concentrations of Mn, Zn and Hg in the carapace were correlated with whole body burdens, indicating that the carapace is a useful non-lethal indicator for monitoring heavy metal levels in the body of the sea turtle.