Tritiated water isn't particularly bioaccumulative: chemically, it's water and acts like it. The body doesn't preferentially retain tritium compared to normally

Tritiated water isn't particularly bioaccumulative: chemically, it's water and acts like it. The body doesn't preferentially retain tritium compared to normally hydrogen, so it doesn't concentrate in tissues like, say, dioxins or mercury. It can be incorporated into tissue, but not preferentially to normal hydrogen. Making dioxins with tritium atoms in place of hydrogen would probably be a bad idea, though.