Organochlorine residues in eggs of loggerhead and green sea turtles nesting at Merritt Island, Florida--July and August 1976

Eggs from nine clutches of loggerhead turtles (Caretta caretta) and two clutches of green turtles (Chelonia mydas) were collected as they were laid on Merritt Island, Florida. Eggs were incubated, frozen, and analyzed for organochlorines. Levels of DDE and PCB, the major contaminants, averaged less than 0.08 ppm in loggerhead eggs and were even lower in green turtle eggs. These concentrations are far below levels thought to be potentially harmful. Loggerhead eggs were frozen after 43-52 days incubation; both DDE and PCB declined significantly during this interval. Authors estimate that DDE averaged about 0.2 ppm in loggerhead eggs when they were laid. DDE levels in eggs of both turtle species were less than levels in eggs of crocodiles (Crocodylus acutus) from Everglades National Park and in eggs of 13 species of aquatic birds nesting on Merritt Island. The remarkably low residues in the turtle eggs probably indicate that, when not nesting, the turtles live and feed in areas remote from Florida.