Uranium is an element with chemical and radiological properties that have made it useful in industry and commerce, but toxic at sufficiently high levels to humans and the environment. Various analytical methods are available to determine the presence, concentration, or quantity of uranium or its isotopes in a range of media. Results confirm that uranium is present in ambient air, water, and soil, so human exposure is assured. At least seven of its more than 100 mineral forms are found at mineable levels in various parts of the world, and the primary producers are in Australia, Canada, China, Kazakhstan, Namibia, Niger, Russia, the United States, and Uzbekistan (WNA, 2013). Uranium is mined primarily for the 235U isotope. The process of enrichment adjusts the ratio of the three natural isotopes (234U, 235U, and 238U) to produce two fractions. The one with an increased proportion of 235U is defined as enriched uranium and is the source of energy production for nuclear reactors and weapons. The remaining portion is depleted in 235U (and also in the more radioactive 234U isotope), so it is termed depleted uranium, and it is less radioactive. Apart from energy production, uranium is used in a range of products that include glass tinting agents, ceramic glazes, gyroscope wheels, chemical catalysts, shields for high-intensity radioactive sources, X-ray tube targets, and military armor and kinetic penetrator munitions, but no longer in dental porcelains. Estimated intakes from water and food are each 0.9-1.5 μg/day, with this being variable based on the source of water (higher in groundwater) or type of diet (higher in beef, beef kidney and liver, onions, parsley, and salt, but lower in poultry, fruit juices, fresh and canned fruits and vegetables, and dairy products). Air concentrations are normally low. The highest human exposures result from drinking well water high in uranium and working in the uranium milling and production industries, with the greatest environmental remediation challenge coming from large volumes of mine and mill tailings. Human exposure involves inhalation and ingestion (and, since 1991, military metal fragment wounds). Uranium intestinal absorption is low (0.1-6%, with central values of 1-2.5%), increases with solubility, and is higher for animal neonates and those fasting or iron deficient than for adults. Dermal absorption may not occur across intact skin for insoluble forms, and increases with solubility and extent of skin damage and excoriation, but is lower through severely damaged (e.g. burned) than intact skin (Petitot et al., 2007a). Once absorbed in to the blood, its distribution and elimination kinetics are primarily a function of oxidation state. Uranium entering body fluid in the tetravalent state is converted to the hexavalent uranyl ion, which complexes with available citrate or bicarbonate in blood, or proteins in plasma. Distribution is throughout the body, with primary long-term concentration in the lung (for heavy occupational exposure to insoluble forms), bone, liver, and kidney. Initial elimination is rapid, with at least two phase components for excretion. Computer programs are available to estimate the timeframe concentrations in and radiation doses to the various organs and tissues. It is estimated that inhaling 1 μg U/day eventually results in a kidney concentration of 0.003, 0.00075, and 0.000078 μg U/g for types F, M, and S uranium, respectively (Leggett et al., 2012). Federal Guidance Report No. 13 (EPA, 2005b) provides Sv/Bq conversion factors for estimating the radiation dose received by the body and selected organs from inhaled or ingested uranium isotopes. Uranium has been found to cross the placenta and to be excreted in breast milk based on elevated levels in the rat fetus following oral exposure of the dam before mating and during gestation and lactation (Sanchez et al., 2006). Overexposure can impact human and animal health. Although uranium is both a chemical and a radioactive material, it has been determined that its adverse health effects are primarily a result of its chemical rather than radiological toxicity (ATSDR, 2013). The damage mechanism for uranium retained in the lung involves injury to the deep lung with the long-term potential for fibrosis and emphysema. The mechanism for renal toxicity involves the accumulation of uranium in the tubular epithelium and subsequent progression to either tubulointerstitial nephritis or tubular necrosis based on exposure level and duration. This may be associated with increased cellular oxidative stress, altered expression of genes involved in cell signaling, and inhibited sodium-dependent phosphate and glucose transport systems. The impact on liver enzymes and receptors might affect drug therapy regimens. Uranium can also interfere with bone remodeling and liver integrity. The health effects from exposure by inhalation, oral, and dermal routes are primarily to the kidney, and it has been shown that this damage can be reversible if not severe. Less severe effects have been observed for the liver and lung, as well as the nervous and reproductive system. Uranium has not been classified as a carcinogen, and cancer has not been observed in high-dose human and animal studies, other than at metal implantation sites, where it has been attributed to a foreign body response. If cancer should develop, bone sarcomas are regarded as the most likely to occur because uranium and radium undergo long-term deposition in the bone and radium dial painters developed bone sarcomas.