Assessment of human exposure to lead : comparison between Belgium, Malta, Mexico and Sweden

Abstract

In 1978 an international UNEP/WHO project was initiated to assess human exposure to lead and cadmium through biological monitoring. The development and results of the project have been published in "Assessment of Human Exposure to Lead and Cadmium through Biological Monitoring" (Vahter, 1982; Friberg and Vahter, 1983). The following countries participated in the project: Belgium, India, Israel, Japan, Mexico, People's Republic of China, Peru, Sweden, USA and Yugoslavia. Scientific responsibility for the implementation of the project was delegated to a Coordinating Institution: the National Institute of Environmental Medicine and the Department of Environmental Hygiene of the Karolinska Institute, Stockholm, Sweden. About 200 teachers from one urban area in each country constituted the target group. Lead and cadmium were measured in samples of venous blood. The programme was carried out in conjunction with a rigid quality control programme. The results showed that there is considerable variation in metal exposure between the areas studied. For example, for lead in blood median values ranged from about 60 lig Pb/I in Beijing and Tokyo to 220 ltg Pb/I in Mexico City. The 90-percentile values ranged from 89 .tg Pb/I in Tokyo to 346 ltg Pb/I in Mexico City. The project did not study the different sources of observed differences between countries. The project concluded with a recommendation that biological monitoring should also be carried out in other areas. Such an expansion of the project should include integrated monitoring of pollutants in different environmental media, e.g. food, drinking water and air. The use of integrated monitoring was subsequently endorsed by a UNEP/WHO Government Expert Group in 1982. The present paper describes a follow-up study of the above mentioned UNEP/WHO Pilot Project on Assessment of Human Exposure to Lead and Cadmium through Biological Monitoring, carried out in 1983/84.