Determination of aluminium in Slovenian foodstuffs and its leachability from aluminium-cookware

Abstract

Al toxicity is well known, particularly in patients with chronic renal failure. To estimate the dietary intake of Al in man it is necessary to determine the total Al concentrations in different foodstuffs. For this purpose twenty one different vegetables growing on peat and clay soils were analysed. Water-soluble Al was determined in soil samples to estimate the easily soluble Al fraction available to plants and to find whether plants may also accumulate higher Al concentrations from soils low in Al. Al was further determined in wheat, eggs, baby foods, fish, mussels and twenty samples of total diet. In addition, beverages and herbal and black tea infusions were analysed for Al content. Total Al in foodstuffs was determined by ICP-AES after microwave digestion. The accuracy of the procedure was checked by the analysis of CRM 1570a (Spinach leaves). Good agreement between measured and certified values was obtained. In order to estimate the extent of leaching from Al utensils, sauerkraut and sour turnip were cooked in Al-cookware. The results indicate that concentrations of Al in foodstuffs (dry weight) were in general below 30 mg kg −1, while in total diet they ranged from 3 to 6 mg kg −1 Al. High Al concentrations were found in mussels (about 300 mg kg −1) parsley and lamb's lettuce. Lamb's lettuce contained about 400 mg kg −1 of Al, irrespective of whether it was growing on peat soil low in total and water-soluble Al or in clay soil rich in Al. Black tea infusions contained up to 300 mg kg −1 of Al, which is 30 times more than herbal tea infusions. Concentrations of Al in beverages were below 0.4 mg dm −3. The results indicated that sauerkraut and sour turnip leach appreciably high concentrations of Al during cooking in Al utensils (313 and 260 mg kg −1, respectively), so the use of such cookware is not recommended for acidic foodstuffs.