Effects of Zinc and Aluminum Hot-dip Galvanized Sheet Steelon the Gill and Hepatopancreas of the Abalone Haliotis discus hannai

摘要

We investigated the toxicity of zinc and aluminum hot-dip galvanized sheet steel to abalone Haliotis discus hannai via changes in the gill and hepatopancreas using histological and transmission electron microscopy analysis. Experimental groups were composed of one control and four exposure conditions (direct or indirect exposure to zinc and aluminum hot-dip galvanized sheet steel). In the control group, aluminum exposure groups (direct and indirect), and indirect zinc exposure group, abalone mortality was not observed until the end of the experiment, and no histopatho-logical changes were observed in the gill and hepatopancreas. However, the direct zinc exposure group exhibited 100% mortality. Ultrastructural analysis of the cytoplasm of ciliated and microvilli-bearing epithelial cells from gill filaments revealed electron-dense vesicles near the cell membrane and disruption of the nuclear membrane. We also observed swollen mitochondria and a loss of mitochondrial cristae. The hepatopancreas showedsimilar changes, and we detected highly electron-dense particles within the vesicles. These results suggest that abalone exposed directly to zinc hot-dip galvanized sheet steel experience acute toxicity, causing damage to cell organelles in the gill andhepatopancreas and, finally, inducing mortality.