Testing exposure to metals and their compounds in fractions of dusts emitted in processes of machining metals

The task consisted in an analysis of sampling and separating into fractions related to variously defined fractions of dusts and a review of methods of determining metals in samples sampled on different kinds of filters used for separating particles of dust containing metals and their compounds. A way of preparing samples sampled on PTFE filters with pores of various sizes was developed and validated. It is used for determining with atomic absorption spectrometry concentrations of chrome, zinc, manganese, copper, nickel, lead and iron. It turned out that mean values of the indices of recovery of selected metals both from PTFE filters with the diameter of 25 mm and the pore size of 0.5 ?m and from PTFE filters with the diameter of 37 mm and the pore size of 2.0 ?m exceeded 95%. To assess exposure to metals in fractions of dusts in selected processes of machining metals, measurements were conducted at 50 workstations of machining varying in the metal that was machined and in the technological processes. The following were done at the workstands that were studied: cutting, milling, threading, hammering, casting, trimming, polishing, grinding, turning and drilling of elements made of brass, cast iron and steel. At each workstation air was sampled for determining selected metals in total dust and in respirable dust, and in fractions of dust with various particle size. An analysis of the contents of individual metals in the respirable fraction in relation to the contents of those metals in the total dust fraction showed a high percentage share of individual metals in respirable dust (over 50%), especially at the workstations of milling, threading, hammering, polishing, grinding, turning and drilling of metal elements. A procedure for determining selected metals in dust fractions with atomic absorption spectrometry and information materials were developed as part of this task.