-Cadmium is a naturally occurring element in the earth's crust. Pure cadmium is a soft silver-white metal.
             -Cadmium is most off encountered in combination with other elements such as oxygen, chlorine, and sulfur.
             #4. Ways to be exposed to cadmium?
             -Small amounts of cadmium occur naturally in air, water, soil, and food
             -Cadmium is passed along the food chain, bottom up.
             -Phosphate fertilizers and sewage sludge increase cadmium levels in soil
             -Burning of fossil fuels releases cadmium (coal and oil)
             -EPA limits discharge amounts by companies into environment
             -Maximum contaminant levels set for drinking water
             -OSHA has established maximum and average exposure time limits to cadmium
             -FDA limits amount used in ceramic plates, cups
             -Chlorofluorocarbons (cfc's) are a family of compounds containing chlorine,
             -Invented in 1920's as safe alternative to sulfur dioxide and ammonia refrigerants
             . -They are unreactive, and have low flammability, plus low toxicity.
             -Stable in atmosphere: very stable: 10 to more than 100 years.
             -As solvents in cleaning electronic components and metals
             -As blowing agents in foam plastic manufacturing
             -CFC's are safe to use in the lower atmosphere, but the problem occurs when they
             Drift to the upper atmosphere or stratosphere.
             -Discovered in 1973 that CFC's damage ozone
             - UV destroys CFC's and Chlorine is released which destroys ozone
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