In a
previous study carried out in the Pacific coast of Mexico
(Paez-Osuna et al., 1998, 2002) using bivalve mollusks as
biomonitors, it was found that in lagoons of AltataEnsenada
del Pabellon and Navachiste, Sinaloa which
are surrounded by agricultural lands, the soft tissue of
oyster Crassostrea corteziensis had concentrations of up
to 216 lg g1 of Cu and 655 ng g1 of PCBs, respectively.