Urban population exposure to lead and cadmium in east and south-east Asia

Information is still scarce for many Asian countries on general population exposure to two potentially toxic heavy metals of lead (Pb) and cadmium (Cd ). The present review on publications from this study group is intended to provide an overview of the non-occupational exposure to Pb and Cd among gen eral populations in east and south-east Asia. During the period of 1991-199 8, surveys were conducted in four cities in south-east Asia, five cities in mainland China, and two cities each in Japan and Korea. Peripheral blood, morning spot urine and 24-h food duplicate samples were collected from 20-5 0 non-smoking adult women in each survey site. The samples were digested by heating in the presence of mineral acids, and then analyzed by inductively -coupled plasma mass spectrometry for the metals in blood (Pb-B and Cd-B), in urine (Pb-U and Cd-U), and in food duplicate (Pb-F and Cd-F). Measures w ere subjected to statistical analysis with an assumption of log-normal dist ribution. Pb-B, Pb-U and Pb-F levels varied substantially among the II urba n sites; GM distributed in ranges of 32-65 mu g/l for Pb-B, 2.1-7.5 mu g/g cr (creatinine) for Pb-U, and 7-32 mu g/day for Pb-F. The same was also the case for Cd exposure parameters, the distribution ranges being 0.5-1.8 mu g/l for Cd-B, 1.2-3.1 mu g/g cr for Cd-U, and 5-32 mu g/day for Cd-F. It ap peared that the exposure to Pb and Cd was highest in Kuala Lumpur, and Toky o + Kyoto, respectively, and lowest in Tokyo + Kyoto and in Manila. Additio nal surveys in Japan showed that Pb exposure was even lower in rural areas than in Tokyo + Kyoto. When compared with the values reported in the litera ture, Pb exposure levels among Asian populations appear to be similar to th e levels in Europe and in the United States, whereas Cd exposure seems to b e higher in Asia than in Europe. The contribution of the dietary route in P b absorption was variable and was inversely related to the extent of air po llution, whereas Cd uptake was almost exclusively via the dietary route wit h little contribution of the respiratory route. (C) 2000 Elsevier Science B .V. All rights reserved.