Body Burdens and Distribution of Mercury and Selenium in Striped Dolphins

抄録

Weexamined variations in the burden of total mercury and selenium with age in striped dolphins (Stenella coeruleoalba). The amount of total mercury accumulated in the whole body increased with age and reached a constant level at about 16 years of age. The constant total mercury burden level in males was slightly higher than that of females. A similar tendency was observed for the body burdens of methylmercury in males and females. The body burden of selenium remained constant for the dolphins of ages between 5 to 12 years, and after that it sharply increased with growth until about 17 years of age. The sum of total mercury in muscle, liver and blubber was about 90% of that in the whole body. Approximately 90% of the methylmercury in the whole body was in the muscle. The total selenium content in muscle, liver and blubber comprised 67 - 80%of that in the whole body of immature individuals and mature males. The accumulation of selenium in various tissues varied among mature males, pregnant females and lactating females. The con centration ratio of total mercury to selenium was lower in females at the later gestational stage than in mature males, and the ratio was the highest in females at the early gestational stage and lactating females.