The results, published by the Food Standards Agency (FSA), examined the concentrations of aluminium, arsenic, cadmium, copper, iron, lead, manganese and zinc in 310 food samples.
The levels found in the survey were compared against legal limits where they exist that is, for arsenic, lead and cadmium. Four samples of cultivated mushrooms and nine samples of nuts showed levels of cadmium above these limits.
One sample of root vegetables and seven samples of nuts showed levels of lead above the limits. The agency said that it has informed both local authorities in order for them to consider whether to take enforcement action, and relevant companies.
"None of the results of this survey pose a significant risk to peoples health, and FSA advice to eat at least five portions of fruit and vegetables, each day is unchanged," said the FSA.
The survey was undertaken to provide data for a future review by the European Commission of permitted levels of these metals in our diet. Last year the EC revised the directive to widen the scope of limits on heavy metals and mycotoxins in foods, among other changes.
The new regulation consolidated and replaced European Commission regulation 466/2001 and its previous amendments, and introduced changes that require food processors to take greater care in the sourcing of the ingredients used in their products.
Other changes include an amendment on measures applying to dried, diluted, processed and compound foodstuffs. This would require food businesses to provide data on the specific concentration or dilution factors used for their products. Manufacturers using groundnuts, derived products, and cereals must clearly label them indicating their intended use, either for feed, food or other purposes.
The Commission regulations are expected to be published in the Official Journal of the European Union shortly and will apply from 1 March 2007.
The FSA, for its part, regularly monitors the concentrations of metals and other elements in food. Some foods included in the FSA survey such as venison, peanuts, honey, pheasant, sweets and wild mushrooms are not currently included in the EC 466/2001 regulation.
There is still a large amount of work to be done in this field. Some metals and other elements (such as copper, manganese and zinc) can act as nutrients and are essential for health, while others (such as arsenic, cadmium, lead and mercury) have no known beneficial health effects.
Metals and other elements can be present in food either naturally, as a result of human activities (such as farming, industry or car exhausts), from contamination during manufacture/processing and storage, or by direct addition. Excessive amounts of any metal could be potentially dangerous.