If you eat rice, and particularly - in a monstrous irony - the 'healthy' brown variety, or the kind used in baby food, the answer is almost certainly yes.

According to Andrew Meharg, professor of biogeochemistry at Aberdeen University and a world authority on one of the most notoriously poisonous elements known to man, 10% of rice found on British supermarket shelves and 30% of rice-based baby food contains levels of arsenic higher than would be allowed in China, which as the world's largest consumer of the staple has the strictest standards (Britain's were set in 1959).

Arsenic, many forms of which are relatively harmless, is present in vast numbers of foodstuffs, notably fish and seafoods. But it occurs in a deadlier form, and in high concentrations, in rice because the crop is grown in flooded fields: arsenic naturally present in the soil leaches into the irrigation water and is absorbed by the plants.

Long-term exposure substantially increases the risk of lung, bladder and skin cancer. Potent and until recently almost impossible to detect, the poison has been a murder weapon of choice since the middle ages; it is said to have caused the deaths of a couple of popes, a great many Borgias, Napoleon Bonaparte and (accidentally) King George III. The World Health Organisation fears up to 140 million people in 70 countries are being slowly poisoned by arsenic in their drinking water.

But is it dangerous in your food? The Food Standards Agency says no; Meharg says awareness of a potential problem is "very new" and the evidence needs to be evaluated carefully. If your diet is predominantly rice-based (as it is for Britain's Bangladeshi, Indian and Pakistani communities) or if you buy a lot of baby food for your infant, it might be a question worth pondering.

From The Guardian, g2 section. Mon 10th Sep 2007