Dietary exposure to antimony, lead and mercury of secondary school students in Hong Kong.

The aim of this first study was to determine the dietary exposure of antimony, lead, mercury in foodstuffs consumed by secondary school students in Hong Kong. Around 100 composite food items were purchased and then cooked prior to analysis. Antimony was measured by hydrogen generation (HG)/inductively coupled plasma-mass spectrometry (ICP-MS), while lead was determined by ICP-MS. Total mercury was measured by cold vapour atomic absorption spectrometry. The detection limits for antimony, lead and total mercury were 1, 0.6 and 3 microg kg(-1), respectively. The dietary intake of antimony, lead and total mercury for an average secondary student were estimated to be 0.252, 1.98 and 0.92 microg (kg bw)(-1) week(-1), respectively. The dietary intake of antimony, lead and total mercury for high-consumer secondary student were estimated to be 0.567, 5.09 and 2.33 microg (kg bw)(-1) week(-1), respectively. The main contribution to antimony, lead and mercury were milk, vegetables and seafood, respectively. The Tolerable Daily Intake (TDI) of antimony, as recommended by WHO, is 6 microg (kg bw)(-1) week(-1), while the Provisional Tolerable Weekly Intakes (PTWI) of lead and mercury, as recommended by JECFA, are 25 and 5 microg (kg bw)(-1) week(-1), respectively. The estimated exposure values for secondary school students were compared to these safety reference values. For the relevant population, this study confirms the low probability of health risks from these metals via food consumption.