Asbestos is a naturally occurring mineral that can be processed to form practically indestructible fibers. People who work with asbestos are exposed to a significant hazard, since inhaling or ingesting ever very small amount of asbestos is associated with an increased risk of cancer of the lungs and the intestinal tract in susceptible people. But there is also evidence that relatively small amounts of the general public. City dwellers breathe been found in wines filtered with asbestos mesh, in homes and cars contain some asbestos in insulation, water pipes, brake linings, and the like.
Lead
Lead, like asbestos, is a naturally occurring element, usually distributed in low concentrations. Since the introduction of the automobile, however, the lead content of the atmosphere has greatly increased, for it has long been an additive in leaded gasoline. Furthermore, until recently lead was used in many paints, automobile batteries, ceramics, glassware, pipes, and other manufactured goods. The basic danger from lead lies in lead poisoning, which causes weakness, loss of appetite, anaemia, and damage to the nervous system.
Greater danger is lead poisoning that may occur when children eat lead based paint and putty, usually off walls and woodwork in older buildings. Hundreds of children have died thousands of other have suffered chronic symptoms related to it. Studies have found that children whose blood contain elevated levels of lead tend to score lower on intelligent tests than children with normal blood.
Mercury
Mercury is a naturally occurring element that is widely distributed in the earth’s crust. In its elemental form, mercury is a very stable metal, and mercury salt are considered quite insoluble. However, certain microorganism can convert elemental mercury and other form of mercury into an organic form, enough quantities, produces devastating symptoms.
Unfortunately, this fact was not discovered until several years after a tragic incident. From the early 1930s until 1971, certain Japanese factories released industrial wastes containing substantial quantities of mercury into the
As a result of the Minamata episode and other mercury related disasters, most industrialized nations have instituted strict regulations prohibiting mercury pollution, and acute mercury poisoning from contaminated food is now far less likely than it was a decade ago.
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