Dental amalgam controversy emissions. The WHO also points out that amalgam separators, installed in the waste water lines of many dental offices, dramatically decrease the release of mercury into the public sewer system. In the United States, most dental practices are prohibited from disposing amalgam waste down the drain. Critics also point to cremation of dental fillings as an additional source of air pollution, contributing about 1% of total global emissions. It is the position of the FDI World Dental Federation as well as numerous dental associations and dental public health agencies worldwide that amalgam restorations are safe and effective. Numerous other organizations
Chemical element whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than 1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of a "pure element". In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the