[The dust factor of the work and adjacent environments in the working of manganese ore].

The dust professional exposition of the above ground workers in the mines "Obrochishte" at the village of Tsŭrkva, Varna Province has been evaluated as well as the dust pollution in the atmosphere of the village in respect to the hygienic standards for quartz-containing sand and manganic aerosol. The results show that the pollution with quartz-containing dust is in the normal ranges according to all hygienic parameters for fibrogenic dusts in working environment and the workers are not exposed to risk of silicosis. A greater than the standard exposition to manganic aerosol (from 1.1 to 5 PDK) has been found out in some groups of workers in the ore-dressing plant, in truck drivers of the intra-fabric transport, in fadromists and heavy scraper workers. The manganic aerosol is found to be a pollutant of the atmosphere also, and the cause of this is thought to be the mine storages in the open-air and the poor state of the intra-fabric roads.