London - Arsenic may be something you think you last encountered in an Agatha Christie plot, but, in fact, the deadly poison can be found all around us, including on our plates.
An investigation by British television channel Channel 4 has revealed that many popular rice products - including Kellogg’s Rice Krispies, Cheerios and some baby food - may contain potentially dangerous levels of the contaminant.
This is because rice is grown in flooded conditions in countries such as India and Bangladesh. The water causes the arsenic that is usually locked up in the soil to be released and this is absorbed by the rice.
While there are strict regulations for levels of arsenic in drinking water, there are none for food.
And though levels in rice aren’t toxic in the short term, no research on long-tern exposure has been done.
The best variety of rice to choose is basmati, which absorbs less arsenic from the soil.
It is also possible to remove 80 percent of arsenic from rice in the cooking process. The key is to rinse thoroughly before cooking, to boil it in the largest volume of water possible (which allows the poison to leach out) and to rinse it again in boiling water after cooking.
Scarily, however, arsenic is not the only poison being served up in our homes. Heavy metals ranging from lead to mercury can be found in many of our favourite foods.
Why vegetarians are most at risk
Cadmium is found naturally in almost all vegetables and wholemeal grains, as they take it in from the soil.
The metal is a carcinogen as well as a renal toxicant, which means it builds up in the kidneys and can damage them in the long-term, causing kidney disease in extreme cases. Shockingly, if you eat cadmium today, half of it will still be in your body 40 years from now - it lurks in the kidneys and liver.
Andy Meharg, professor of biological sciences at Queen’s University Belfast, says: “Ironically, it’s people who are living most healthily and who have a vegetarian diet who often have higher exposures to cadmium.
“South-West England has elevated cadmium in vegetables because of mining, and it is also a concern in industrial areas and allotments in cities.”
However, as with food containing arsenic, preparation can limit the impact.
To get rid of cadmium you should peel - or at least wash - vegetables because much of the contamination comes from soil particles sticking to the outside of produce.
How mercury hides in tuna
Mercury released into the ocean by industrial and mining processes can affect seafood. Once in the water, it is consumed by fish and accumulates as they are consumed by predators, meaning the creatures at the top of the food chain amass the highest amounts.
Shark, swordfish and tuna are the main dietary sources of mercury, which can have a damaging effect on foetal and child development.
In adults, it has been associated with depression, tremors, insomnia, headaches and personality changes.
The metal builds up in the body, particularly in the kidneys and liver. The NHS advises that children, pregnant women and women trying to become pregnant should not eat swordfish, shark or marlin, and other adults should have no more than one portion a week.
Sweets laced with aluminium
Surprising research by the Food Standards Agency last year said the highest level of aluminium was found in a sample of loose tea.
Tea is grown in acidic soils - which contain relatively high levels of aluminium - and the metal is stored in the leaves.
Sweets can also contain aluminium (used in food colouring).
And it can also be found in water (purified with aluminium sulphate, which makes micro-scopic impurities clump into particles large enough to be filtered out).
Christopher Exley, professor in bioinorganic chemistry at Keele University, has described this century as “the aluminium age”.
He warns that excess aluminium is deposited around the body, including the brain, and contributes towards neuro-degenerative diseases such as Alzheimer’s, Parkinson’s and multiple sclerosis.
“In my opinion, there is no safe level,” he says. “There are levels that may not impact upon health in a lifetime, but these vary between individuals.
“The best thing you can do is take precautions. Avoid processed food - instead, buy fresh ingredients.
“Avoid unhealthy fizzy drinks, particularly those in aluminium cans, as well as energy drinks and iced tea.
“And don’t buy long-life drinks in those cardboard cartons which contain a layer of aluminium foil.” -Daily Mail