COMPARISON OF METHODS FOR PERSONAL SAMPLING OF INHALABLE AND TOTAL LEAD AND CADMIUM-CONTAINING AEROSOLS IN A PRIMARY LEAD SMELTER

It has been proposed that future occupational aerosol exposure standar ds be based on particle size-selective sampling criteria that more acc urately reflect worker exposure. In relation to methods currently used for determining individual workers' lead exposures, the widely used 3 7-mm, closed-face, plastic sampling cassette is known from laboratory wind tunnel studies to undersample significantly compared with estimat ions of aerosol actually inhaled, especially for large particles. The present study investigated the degree to which this is borne out in fi eld sampling by using side-by-side sampling in selected work sites in a primary lead smelter. Exposures to ''total'' airborne lead and cadmi um as measured using the 37-mm sampler (E-37) were compared with expos ure measurements using the Institute of Occupational Medicine (IOM) pe rsonal inhalable aerosol sampler (E-IOM). There were 166 good sample p airs for lead and 55 for cadmium. The ratio (reflecting the fractional undersampling of the 37-mm sampler, as represented by the ratio E-IOM /E-37) was consistently greater than unity, by factors obtained by reg ression analysis ranging (for different parts of the plant) from 1.39 to 2.14 for lead and 1.29 to 2.12 for cadmium. The factor tended to be greater for parts of the plant characterized by coarser aerosol, cons istent with the physical sampling characteristics of the two instrumen ts. This research is important (1) in assessing the impact of implemen tation of new standards for lead-and cadmium-containing aerosols in th e primary lead production industry, and (2) in the development of new occupational exposure limits based on the inhalable aerosol fraction.