Tuesday, April 27, 2010

Other Hazardous Chemicals

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, 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 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 Pacific Ocean. Marine microorganisms metabolized the mercury to its concentrated as it passed along the food chain to higher organisms. The highest organisms in the chain were human beings, resident of a fishing village on Minamata, whose diet consisted almost solely of fish. The high level of mercury in the fish they ate resulted in fifty-two deaths; more than a hundred other people experienced serious symptoms, including inability to speak, mental retardation, numbness of arms and legs followed by deterioration of muscle tissue, gradual loss of coordination, and emotional disturbance. Many of these victims are now permanently disabled, and children born to mothers who consumed the contaminated seafood are severely deformed.

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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