Trace metals in soft and durum wheat from Italy

A survey was carried out with the aim to assess the levels of some toxic (cadmium, lead) and essential (copper, zinc) trace metals in wheat grown in Italy. A total of 178 samples of soft wheat grain and 239 samples of durum wheat grain from all the Italian wheat-growing regions were pooled into 35 and 38 representative samples respectively. After dry ashing, cadmium and lead were determined by graphite furnace atomic absorption spectrometry (GFAAS), whereas copper and zinc were determined by flame atomic absorption spectrometry (FAAS). In soft wheat the mean and median contents of all samples were (on a dry weight basis) 40 and 33 micrograms kg-1 for cadmium, 16 and 14 micrograms kg-1 for lead, 3.4 and 3.2 mg kg-1 for copper, 33 and 32 mg kg-1 for zinc. Similar levels were found in durum wheat. In this latter case the mean and median were 42 and 39 micrograms kg-1 for cadmium, 15 and 14 micrograms kg-1 for lead, 3.5 and 3.2 mg kg-1 for copper, 34 and 34 mg kg-1 for zinc. Significant differences were detected for some metals in relation to geographical provenance and variety. The average intake of the four selected elements from wheat-based products was estimated for the Italian population.