Airborne fiber concentrations and size distributions of both asbestos and nonasbestos fibers were determined at property boundaries of 4 serpentinite quarries producing crushed stone (quarry property boundary), 10 sites within 10 km of the area with serpentinite outcrops (serpentinite area), and 2 sites in a reference area. The asbestos was identified in 7 rock and 3 soil samples collected in t...

BACKGROUND In recent years, some studies have tried to improve Phase Contrast Microscopy (PCM) for counting asbestos fibers. Due to the lack of a universally accepted alternative method, this study aimed to improve PCM for better counting of asbestos fibers. MATERIALS AND METHODS Confirmed asbestos standards were applied using a dust generator for sampling. Sampling from the dust generator wa...

Fiber length and diameter are important factors in the pathogenicity of asbestos. We examined the relative toxicity of long and short crocidolite asbestos fibers in vitro and in vivo. Both long and short crocidolite asbestos fibers were toxic to elicited macrophages in vitro. Similar to native crocidolite asbestos, long and short Tibers stimulated the release of reactive oxygen metabolites from...

This article reviews studies of the carcinogenicity of mineral fibers, notably asbestos, and presents seven major recommendations for further research. Mineral fibers represent the greatest cause--after cigarette smoke--of respiratory cancer due to air pollutants. Past asbestos exposure may currently account for 2000 mesothelioma deaths per year and 4000 to 6000 lung cancer deaths per year. All...

The authors report the case of a 65-year-old accountant whose only asbestos exposure was during a summer job 50 years earlier in a California vermiculite expansion plant. Vermiculite is a silicate material that is useful in building and agriculture as a filler and insulating agent. He developed extensive fibrocalcific pleural plaques and end-stage pulmonary fibrosis, with rapidly progressive re...

Asbestos fibers are highly cytotoxic to cultured mammalian cells and produce chromosomal aberrations in several rodent cell types. There is some uncertainty in the literature as to whether these fibers are clastogenic to cultured human cells. Asbestos fibers do not produce either DNA damage or back mutations in prokaryotic assay systems, and they do not appear to cause DNA strand breaks in eith...

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 c...

Asbestos is a known carcinogen and exposure can lead to lung cancer and malignant mesothelioma. To examine the effects of asbestos fibers on human immune cells, the human T cell leukemia/lymphoma virus (HTLV)-1 immortalized human T cell line MT-2 was employed. Following continuous exposure to asbestos fibers for more than eight months, MT-2 sublines showed acquisition of resistance to asbestos-...

Health risks from asbestos exposures have been evaluated, considering past professional histories when exposures at workplaces were higher than today. A linear no-threshold (LNT) model has been applied, although its relevance is unproven. Fibers are often found in the lungs and pleura of deceased people. Fiber findings do not prove that a disease is caused by asbestos. It is reasonable to assum...

Asbestos fibers have been shown to generate reactive oxygen species using a variety of in vitro assays. It is hypothesized that these highly reactive metabolites mediate the development of malignant mesothelioma induced by asbestos fibers. DNA is a potential target of oxidant attack. Adaptive responses to oxidant injury have been described during exposure of mesothelial cells to asbestos fibers...