September 7, 2009

A small and preliminary study found that certain forms of arsenic, which appear in seafood and are thought to be harmless, might actually be toxic.

Even more troubling, the researchers found that, while arsenic mostly passes right through some people, the substance seems to linger inside others for an extended period.

New research suggested that regulations might not be as strict as they should be.

Arsenic, a carefully monitored poison, is an odourless, tasteless element that occurs naturally in rocks, soil, air, plants and animals.

Arsenic comes in at least 50 forms, which can be grouped into two main categories: Inorganic forms that appear in water and rice, and organic ones that show up in seafood.

Organic forms have long been considered harmless, and levels in seafood are not currently regulated in most places.

The research showed that the synthetic organic arsenic broke down into potentially toxic forms over the course of digestion. This finding raises new concerns about the levels of organic arsenic in seafood, which the European Food Safety Authority is already considering regulating.

The Environmental Protection Agency and other organisations around the world have set strict limits for safe levels of arsenic in drinking water.