Crops grown in south-west England have been found to contain higher concentrations of arsenic than those grown elsewhere, according to latest research.
The Food Standards Agency (FSA), which commissioned the research, said however that the levels reported do not increase concern about risk to human health.
The disparity is linked to the relatively high natural levels of the toxic element in the region's soils, the study added. The University of Aberdeen research found that the relationship between soil arsenic levels and levels in produce varied widely from crop to crop.
Carrots, potatoes, rhubarb and currants from sample farms in Cornwall contained arsenic levels on average several times higher than comparison crops from Aberdeenshire.
The report concluded: "Eating habits of those in arsenic-elevated soil regions need to be assessed to predict risk of exposure from inorganic arsenic."
Overall, leafy vegetables (kale, chard, lettuce, greens and spinach) were found to have the highest concentrations of arsenic and cadmium. But correlation with levels of either element in the soil was low or absent in these cases.
The study also recorded levels of arsenic in potato skins at six nanograms per gram, 75 times greater than that in the flesh.
Food regulations Levels in question after safety ruling
Both the Food Standards Agency (FSA) and the European Food Safety Authority (EFSA), to which the University of Aberdeen report has been passed, have previously urged that levels of arsenic, cadmium and lead in food should be reduced.
There are currently no EU-wide regulations for arsenic levels in food after the EFSA ruled that previous safety limits were inadequate.
But in a statement, the FSA said: "The levels of metals reported in this study do not increase concern about risk to human health. Our current advice on how to wash and peel fruits and vegetables remains the same."