Assessment of Pb and Cd in seed oils and meals and methodology of their extraction

•Heavy metals in rapeseed oils conformed to standards for food products.•(NH4)2EDTA and K2C4H4O6 effectively removed Pb and Cd from the seed meals.•The nutrient contents of the seed meals were hardly decreased after extraction.•The glucosinolate content was lower than the standard for rapeseed meal.

Oil seed, which is a secondary product in phytoremediation, contaminated with heavy metals should be disposed of in an appropriate fashion. In this study, heavy metal concentrations found in oilseed rape and peanut oils were below 0.1 mg kg−1 after extractions, being found most of the heavy metals in meals rather in oils. Extraction experiments were carried out to determine the optimum methodology for the removal of Pb and Cd from seed meals using K3C6H5O7, K2C4H4O6 and (NH4)2EDTA. The highest extraction of the Pb and Cd in the seed meals was achieved using 30 mM extractant solutions at 30 °C for 24 h and a three-step extraction procedure. K3C6H5O7 and K2C4H4O6 had less impact on the removal of nutrients than (NH4)2EDTA.