MWCNT exposure assessment in occupational settings.
Khaliullin T; Zalyalov R; Birch EM; Kagan VE; Shvedova AA; Fatkhutdinova LM
Toxicologist 2014 Mar; 138(1):160
The production of Multi-walled carbon nanotubes (MWCNTs) steadily increases all around the world. However, recent toxicological data raise concerns about their potential risk to human health, particularly upon occupational exposures. The aim of this study was to evaluate the occupational exposure to MWCNT at one of the manufacturing facilities in Russia. The sampling was performed at different sites during the entire technological process. Elemental carbon (EC) analysis was performed using modified NIOSH 5040 method. TEM analysis was performed using modified NMAM 7402 method. The highest MWCNT aerosol short-term concentration was registered during the reactor cleanout process, reaching 157 ug/m3. Time-weighted average (TWA) concentration was respectively 29.6 ug/ m3 for the 8-hours shift. Respirable fraction TWA concentrations for EC at different workstations ranged from 0.53 to 6.11 ug/m3. TEM showed the presence of MWCNT-containing agglomerates at all technological stages, also detectable on non-working days. Agglomerates size ranged from 1 to 10 um; no individual MWCNTs were found. The highest EC values were found in samples obtained during reactor cleanout and harvesting, whereas laboratory handling produced the lowest MWCNT mass concentration values. In the absence of relevant OEL currently set in Russia we compared the maximum 8-hr TWA concentrations with the NIOSH recommended exposure level - 1 ug/m3. The 6.11 ug/m3 EC 8-hr TWA mass concentration value - determined during product harvesting - dictates the necessity of exposure control aimed at the reduction of potential adverse health effects in workers. Repeated exposure assessment is required after exposure controls installation. Direct online particle counters should be also used for mapping and identification of critical exposure points.
Toxicology; Cell-function; Cellular-function; Cell-damage; Nanotechnology; Exposure-levels; Pulmonary-disorders; Pulmonary-function; Pulmonary-system; Pulmonary-system-disorders; Molecular-structure; Molecular-biology; Fibrosis; Exposure-levels; Laboratory-animals; Animals; Pathology; Humans; Men; Women; Biomarkers; Aerosols; Age-groups; Smoking; Air-samples; Work-environment; Workers; Risk-factors; Sampling
Manufacturing; Public Safety
The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona