Workplace atmospheric asbestos levels in different plants manufacturing asbestos-cement roofing sheets in India

AbstractEnvironmental monitoring was conducted to determine the workplace atmospheric asbestos levels in three different plants of an asbestos-cement (AC) roofing sheet manufacturing industry located in North India. Air samples were collected for analysis of asbestos fibers at key locations in all the three plants including fiber warehouse and factory main gate in order to assess the industrial hygiene conditions prevailed in work zone of this factory. A total of 24 samples were collected and analyzed by phase-contrast and polarized-light microscopy. Observations on asbestos fibers collected on membrane filters suggest that they are chrysotile asbestos and their average concentrations ranged between 0.036–0.148 fiber per cubic centimeter (f/cc) (mean 0.075 ± 0.034 f/cc). These fiber counts are less than the existing Indian Standard (0.5 f/cc). However, fiber counts in the ingredient mixing locations of all the plants of AC factory are higher than the proposed Indian Standard (0.1 f/cc). Further improvement in the pollution mitigation technology is highly desirable in view of the carcinogenic nature of asbestos that persists for very long time in the biological systems as well as in the environment

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro

Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analyse the pathway causing such genotoxic effects. Thiobarbituric acid-reactive substances were determined as evidence for the production of reactive oxygen species. Both, asbestos cement as well as chrysotile formed micronuclei and induced loss of cell viability in a concentration- and time- dependent way. Results of TBARS analysis and iron chelator experiments showed induction of free radicals in ACP- and chrysotile exposed cultures. CaSO(4 )appeared to be a negligible entity in enhancing the toxic potential of ACP. The co-exposure of both, ACP and chrysotile, showed an additive effect in enhancing the toxicity. The overall study suggests that asbestos-cement is cytotoxic as well as genotoxic in vitro. In comparison to chrysotile the magnitude of the toxicity was less, but co-exposure increased the toxicity of both

Asbestos fiber counts in work zone area of an asbestos-cement factory

Levels of asbestos fibers in air at work zone in asbestos-cement (AC) sheets manufacturing factory, M/s Sturdy Industries Ltd, Patiala, Punjab have been studied. Air samples were collected from fiber godown, ingredients mixing, AC sheet manufacturing and the main gate. Phase contrast and polarized microscopic observations on asbestos fibers collected on membrane filters suggests that they are chrysotile. A detailed analysis shows the prevalence of chrysotile fibers (0.04-0.07 f/cc) in the working environment. These fiber counts are less than the existing Indian Standard (0.5 f/cc) and proposed Indian Standard (0.1 f/cc)