Laboratory Experiments And High Concentrations Of Asbestos Fibers
Nobody knows for sure how many people have died as a result of asbestos exposure
. Although we cant go back in time and prevent exposure, we can continue to support the important work being done by researchers. One interesting study is called, "Airborne asbestos levels in non-occupational environments in Japan. By Kohyama N. IARC Sci Publ. 1989;(90):262-76. National Institute of Industrial Health, Ministry of Labour Kawasaki, Japan. Here is an excerpt: Abstract - Airborne asbestos levels in non-occupational environments in Japan were determined by analytical transmission electron microscopy (ATEM) for about 100 air samples from various outdoor settings. Asbestos fibres (chrysotile) were found in almost all samples. The fibre (mass) concentrations were in the range of 4-367 fibres per litre (0.02-47.2 ng/m3) with a geometric mean of 18 f/1 (0.3 ng/m3). The mass concentrations were similar to the earlier data reported from other countries. Samples from main roads showed extremely high asbestos concentrations and short fibre lengths compared with those of the other samples. This strongly suggested that braking of vehicles was a significant emission source of airborne asbestos. Laboratory experiments using a brake testing machine demonstrated that asbestos fibres were released during braking. In addition, the present study found high levels of airborne asbestos in some highly polluted areas, such as a serpentine quarry, a town adjacent to an asbestos mine, and factories making asbestos slate-board. On the other hand, chrysotile fibres were also found in air samples from a small isolated island in the Pacific Ocean as well as in ice samples from ten thousand years ago in Antarctica. These facts suggest that chrysotile fibres have been liberated both by industrial activities and natural weathering, and have circulated around the earth.
Another interesting study is called, "Cigarette Smoking, Asbestos Exposure, and Malignant Mesothelioma by Joshua E. Muscat, and Ernst L. Wynder - Cancer Res May 1, 1991 51; 2263. Here is an excerpt: Abstract - In a hospital-based case-control study of 124 (105 male and 19 female) histologically confirmed malignant mesothelioma cases and age- and sex-matched controls, the role of cigarette smoking and the risk of asbestos exposure was investigated. Exposure to asbestos for at least 1 year was likely for 78% of male cases and 16% of female cases, and 90% of males were possibly exposed. Male cases worked predominately in the ship-building industry, construction, or insulation trades. Elevated risks were found for males employed in asbestos-related industries [odds ratio (OR) 8.1; 95% confidence interval (CI) 4.913.5], e.g., shipyards (OR 82.9, 95% CI 25.5269.1), construction/maintenance (OR 8.3, 95% CI 4.614.8), and other asbestos-related jobs (OR 3.2, 95% CI 1.47.2), and for males who self-reported exposure to asbestos or insulation (OR 50.9, 95% CI 21.7119.8). A statistically significant trend was found for the risk of mesothelioma with increasing years employed in non-shipyard asbestos-related occupations. Among women, only one case worked in an asbestos-related industry and two reported domestic contact with asbestos. No association between cigarette smoking and mesothelioma was found for either men or women. We also report the occurrence of mesothelioma in occupations which have not been previously reported.
Another study is called, Clearance and dimensional changes of crocidolite asbestos fibers isolated from lungs of rats following short-term exposure by Victor L. Roggli, Michael H. George and Arnold R. Brody, Environmental ResearchVolume 42, Issue 1, February 1987, Pages 94-105. Here is an excerpt: Previous studies in this laboratory have demonstrated fiber clearance and dimensional changes in chrysotile asbestos using a rat inhalational model of short-term exposure. The purpose of the present study was to determine whether or not similar changes occurred in crocidolite asbestos fibers isolated from the lungs of rats at various intervals after termination of exposure. Fibers were recovered on a membrane filter using a sodium hypochlorite digestion-concentration technique, and the numbers and dimensions of the fibers assessed using scanning electron microscopy. The mass of crocidolite asbestos retained in the lung was then calculated. Of the respirable fraction, 19% was deposited in the lungs, and 25% of this amount was still present 1 month after exposure. These values are similar to the 23% deposition and 19% retention rates for chrysotile determined in our previous study. There was a progressive increase in mean fiber length with time postexposure (P < 0.05), but no significant changes in the diameter of the population of crocidolite fibers retained in the lung. Thus it appears that the tendency for longer fibers to be retained within lung tissue is a characteristic shared by serpentine and amphibole asbestos fibers, whereas longitudinal splitting with progressive decrease in mean fiber diameter in vivo occurs primarily with the serpentine fibers.
We all owe a debt of gratitude to these researchers. If you found any of these excerpts interesting, please read the studies in their entirety.
by: Mont Wrobleski
High Resolution Ct Scans And Workers Exposed To Hazardous Asbestos All Types Of Cancer Treatments - Know Them Gynecomastia Treatment Suggestions Living With Kp - Keratosis Pilaris Best Treatment Discussing Rosacea Treatment How To Discover Essential Treatment When Feet Have A Problem Herpes Simplex Treatment - Choosing the Right Treatment to Control Genital Herpes Growth Hormone Treatment Cost - How Much Does Synthetic HGH Human Growth Hormone Cost? Growth Hormone Treatment Side Effects - Human Growth Hormone Supplement Side Effects Growth Hormone Treatment Adults - Human Growth Hormone (HGH) Treatment in Adults Growth Hormone Treatment Guidelines - Treatment For Short Stature Cause by Turner Syndrome Growth Hormone Treatment For Short Stature - Human Growth Hormone Therapy For Bone Disorder Growth Hormone Treatment Short Stature - Treatment For Intrauterine Growth Retardation