Elemental variations and safety assessment of commercial onions (Allium cepa) by inductively coupled plasma-mass spectrometry and chemometrics

The concentrations of Cd, As, Pb, Se, Fe, Mn, Zn, and Cu in acid-digested onion samples were determined by inductively coupled plasma mass spectrometry, and the corresponding elemental profiles were evaluated by using chemometric techniques. Results from principal component analysis and hierarchical cluster analysis revealed that the spatial variations were highly associated with As, Se, Pb, Zn, and Cd, which advocated dominance of the site related impacts over colour variant of the onions. Such variation pattern could be partly attributed to the consequences of industrialisation and/or urbanisation. From the safety assessment data, concentrations of hazardous elements such as As, Cd, and Pb, were found beyond the World Health Organisation and Food and Agricultural Organisation permissible levels, but within the Malaysian regulatory limits except for Pb. The presence of elevated levels of toxic elements beyond the reference limits in the onion varieties could be of health concern if ingested