Cadmium, copper, lead and zinc concentrations in female and embryonic Pacific sharpnose shark (Rhizoprionodon longurio) tissues.

In this work we compared the cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) contents of muscle, liver and placenta of gestating females of the viviparous shark Rhizoprionodon longurio and of muscle, liver and umbilical cord of their respective embryos. The higher values of the essential Cu and Zn were in embryonic or embryo-related tissues (placenta and umbilical cord). Maternal muscle and liver had the highest values of Pb and Cd, respectively. There were significant direct correlations between the Zn and Cd concentrations of placenta and umbilical cord, as well as between maternal muscle and embryonic livers for Pb and Cd, but the relation between these tissues was inverse in the case of Zn. All correlations between the metal content of embryonic tissues and size of the embryos were negative, suggesting an inverse relation between the rate of mother-to-embryo metal transfer and embryonic growth.