Dietary exposure to lead, cadmium, mercury and radionuclides of an adult urban population in Lebanon: a total diet study approach.

Human exposure to toxic chemicals is suspected of being responsible for a wide range of human health disorders. This study is the first in Lebanon to evaluate the dietary exposure of an adult urban population to three heavy metals (lead, cadmium and mercury) and to radionuclides. Exposure assessment was performed by means of the total diet study approach as recommended by the Word Health Organization. Five 'total diets' were collected during 2003-04. Average and maximal consumer exposure estimates to heavy metals were calculated and compared with appropriate reference values and with intakes reported from other countries. The average dietary intakes of lead, cadmium and mercury represented 7, 17 and 5.6%, respectively, of the appropriate provisional tolerable weekly intakes (PTWI). The mean dietary intake of methylmercury represented 17.5% of the appropriate PTWI. Cs-134 and I-131 were not detected in any of the food samples. Traces of Cs-137 were only found in five food samples. The exposure assessment conducted places Lebanon among countries least exposed to heavy metals through the diet and it highlights the safety of the food supply from radioactive contamination.