This investigation analyzed the Zn-bioaccumulation kinetics in the abalone Haliotis diversicolor supertexta and in the red alga Gracilaria tenuistipitata var. liui for assessing bioconcentration and biomagnification in an aquacultural system. Laboratory exposure experiments estimated uptake and depuration rate constants (i.e., k₁ and k₂, respectively) of H. diversicolor supertexta via nondietary and dietary processes. Bioconcentration factor (BCF) and biomagnification factor (BMF) of H. diversicolor supertexta as well as BCF of G. tenuistipitata var. liui were determined. A simple first-order one-compartment model fitted the uptake and depuration characteristics of Zn-bioaccumulation and successfully determined k₁ and k₂. The resulting values of k₁ and k₂ 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 μg ml⁻¹ Zn seawater without the presence of G. tenuistipitata var. liui. When the abalone were fed with the algae, k₁ and k₂ values were estimated to be 114.5 g g⁻¹ d⁻¹ and 0.636 d⁻¹, respectively. BCF values for 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 show that BMF values for Zn were about 1. Further more, the abalone in the tank 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 comes from the ambient water and not from the algae.
