By the time methylmercury bioaccumulates
up the food chain in large fish such as tuna, the presence of methylmercury could pose a serious threat to both animal and human health.
For example, in aquatic environments, the bacteria Geobacter sulfurreducens transforms the inorganic, less toxic form of mercury into an organic configuration called methyl mercury--a neurotoxin that bioaccumulates
and can cross the blood-brain barrier.
Tributyltin and its relatives are highly toxic to mollusks, causing female snails to develop male sexual characteristics, and it bioaccumulates
in fish and shellfish.
Cadmium is a known endocrine disruptor and often bioaccumulates
within organisms having toxic side effects.
THE EUROPEAN Parliament has approved an import ban on mercury and tough restrictions on using this toxic metal, aimed at preventing its spread in the environment--particularly in water, where it bioaccumulates
in fish and then humans.
When mercury from coal-fired power plants is emitted to the atmosphere, some deposits in water bodies, where it bioaccumulates
One of these forms, monomethyl mercury (MMHg), is a strong vertebrate neurotoxin that bioaccumulates
through food webs.
Selenium, common in runoff from agricultural soil, can be toxic because it bioaccumulates
in birds and fish interfering with reproduction and causing deformities.
Mercury is especially harmful because it builds up in the body, or bioaccumulates
Deltamethrin, a pyrethroid, bioaccumulates
and is a suspected endocrine disruptor.
Authors Marc Lappe and Britt Bailey (Against the Grain, 1998) warn that bromoxynil bioaccumulates
, because it is fat-soluble.
The key concern about mercury is that persists in the environment and bioaccumulates
as it travels up the food chain.