Distribution of tributyltin in tissues of mature Japanese whiting, Sillago japonica and their eggs

Tributyltin (TBT) has continued to pollute the coastal areas therein following global regulation for its use as an anti-fouling agent. The tissue dynamics of TBT in fish have been extensively documented, but few studies on maternal transfer of TBT have been performed. Previously, we reported that TBT was maternally transferred from parent fish to eggs. The present study examined the distribution of TBT in the tissues and spawned eggs of Japanese whiting, Sillago japonica, after dietary exposure to TBT. The percentage distribution of whole-body TBT in each tissue was estimated to be 50% in blood, 29% in muscle, 1.7% in liver, 0.4% in brain, 3.3% in ovary, and 0.47% in eggs spawned in a single day. Of the TBT in whole eggs, 28.8% was in the yolk and 13.5% in the oil droplet. However, the concentration of TBT in the oil droplet was calculated to be 43 times higher than that in the yolk. These results indicate that blood is an important tissue for the accumulation of TBT in fish and suggest that TBT is maternally transferred along with the egg components.