Chemical analysis of toxic elements: total cadmium, lead, mercury, arsenic and inorganic arsenic in local and imported rice consumed in the Kingdom of Saudi Arabia

Rice consumption is a pathway for human exposure to toxic elements. Although rice is a major staple in the Kingdom of Saudi Arabia (KSA) there is limited published data about its toxic element composition. Both imported and locally grown Hassawi rice in Saudi Arabia were collected, digested then analysed by HPLC-ICP-MS for inorganic arsenic (i-As) and by ICP-MS for As, Cd, Pb and Hg. Of these toxic elements, i-As was present at concentrations that might give rise to material concerns about human exposure and public health. Hassawi rice (mean 43 +/- 5 mu g/kg) was found to have significantly lower concentrations of i-As than imported rice (mean 73 +/- 8 mu g/kg). The estimated exposure of adults consuming imported rice in one KSA city reached 0.3 mu g/kg-bw/day, within the margin of safety of the recently withdrawn WHO PTWI for i-As of 2.1 mu g/kg-bw/day and higher than EFSA's 0.06 mu g/kg-bw/day skin cancer BMDL05.