As Standards for Air and Water Pollution
Hazardous air pollutants are those known to cause cancer and other serious health impacts. The EPA regulates the toxic air pollutants. Some examples of these toxic air pollutants include benzene, found in gasoline; perchloroethylene, emitted from some dry-cleaning facilities; and methylene chloride, used as a solvent and paint stripper by a number of industries. Zinc, Pb, and Cu metal isotopes were documented in air and climate studies.
Contaminants in groundwater are also measured with metal standards. As groundwater flows through the ground, metals such as iron and manganese are dissolved and may later be found in high concentrations in the water. Industrial discharges, urban activities, agriculture, and disposal of waste all can affect groundwater quality. Sulfur-34 in water is one metal used to determine environmental difference is lake and ocean waters.
As Standards for Medical Research
Today human metabolic studies most commonly use the stable isotopes of Zinc, Magnesium, Iron and Calcium. Medical Isotopes, Inc. offers a variety of isotopically enriched metals for scientific research use.
For example, iron-57 is widely used in Moessbauer Spectroscopy to determine the oxidation state of iron in protein complexes. Magnesium-25 is used in to study the absorption and excretion of magnesium in metabolic studies. The six stable isotopes of Calcium, Ca-42, Ca-44, Ca-46 and Ca-48) are used extensively in clinical research and in nutritional studies to measure calcium absorption mainly in children, and women where calcium deficiency is strongly related to increasing severity of osteoporosis.