Effects of 500-year mercury mining and milling on cancer incidence in the region of Idrija, Slovenia

The aim of the study was to determine whether the 500-year of mercury mining and milling in the Idrija region in Slovenia and the resulting environmental pollution with mercury and smelting wastes containing radon, has caused an increased cancer risk of the inhabitants. The polluted and the non-polluted parts of the region were defined. Cancer incidence from the two regions was compared. Cancer incidence among miners was investigated separately. In the polluted area male and female cancer incidence was higher than in the non-polluted area. Miners had an excess of incidence of total cancer, of oral and pharyngeal cancers and of lung cancer. As indicated by multivariate analysis the increased risk of miners could be assigned to their smoking and alcohol drinking habits. Higher estimated cumulative exposure to inorganic mercury seems to contribute to their risk as well. Most of the excess cancer incidence of the population from the polluted area could be explained by an unhealthy life style. In the case of lung cancer radon exposure contributes to the increased risk as well. Therefore, a well planed health promotion program and further sanitation of old houses is proposed.