Tissue distribution and kinetics of dietary and waterborne zinc in abalone(Haliotis diversicolor supertexta)

Uptake and depuration of dietary and waterborne zinc (Zn(II)) were examined in aquaculture abalone Haliotis diversicolor supertexta and red alga Graci laria tenuistipitata var, liui using a simple first-order one-compartment b ioaccumulation model. A six-compartment physiologically based pharmacokinet ic model of the disposition of Zn(II) in abalone key organs was developed t o predict tissue distributions. A mean residence time concept was also used to measure the biological persistence for disposition of Zn(II) in each ta rget tissue. The one-compartment kinetic model was successfully fitted to d etermine uptake and depuration rates based on a 14-d exposure experiment. R esults indicated that estimating uptake and depuration rates from depuratio n and short-term uptake experiments was a reliable method of predicting ste ady-state bioconcentration and biomagnification factors. Simulations using the six-compartment pharmacokinetic model for both water and food exposure routes indicated that the whole body Zn(II) concentration would reach equil ibrium in about 120 d. Zn(II) however did not attain a steady-state in the soft tissue and the shell. It is concluded that a pharmacokinetic model is necessary for assessment of Zn(II) risk to abalone key tissues based on the Zn(II)-dynamics in target compartments.