Zn-65(II) accumulation in the soft tissue and shell of abalone Haliotis diversicolor supertexta via the alga Gracilaria tenuistipitata var. liui and the ambient water

This investigation analyzed the Zn-bioaccumulation kinetics in the abalone Haliotis diversicolor supertexta and in the red alga Gracilaria tenuistipit ata var. liui for assessing bioconcentration and biomagnification in an aqu acultural system. Laboratory exposure experiments estimated uptake and depu ration rate constants (i.e., k(1) and k(2), respectively) of H. diversicolo r supertexta via nondietary and dietary processes. Bioconcentration factor (BCF) and biomagnification factor (BMF) of H. diversicolor supertexta as we ll as BCF of G. tenuistipitara var. liui were determined. A simple first-or der one-compartment model fitted the uptake and depuration characteristics of Zn-bioaccumulation and successfully determined k(1) and k(2). The result ing values of k(1) and k(2) of H. diversicolor supertexta were 101.4 ml g(- 1) d(-1) and 0.611 d(-1), respectively, when the abalone were exposed to 1 mu g ml(-1) Zn seawater without the presence of G. tenuistipitata var. liui . When the abalone were fed with the algae, k(1) and k(2) values were estim ated to be 114.5 g g(-1) d(-1) and 0.636 d(-1), respectively. BCF values fo r the alga and abalone were determined to be 170 and 180, respectively; and the BMF value was 1.06 for the abalone. Both field and laboratory data sho w that BMF values for Zn were about 1. Further more, the abalone in the tan k without algae absorbed the same quantity of Zn as the abalone in the tank with alga. From these two findings we conclude that Zn in the abalone come s from the ambient water and not from the algae. (C) 1999 Elsevier Science B.V. All rights reserved.