Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Mercury: A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.Mercury Isotopes: Stable mercury atoms that have the same atomic number as the element mercury, but differ in atomic weight. Hg-196, 198-201, and 204 are stable mercury isotopes.Cypriniformes: An order of fish with 26 families and over 3,000 species. This order includes the families CYPRINIDAE (minnows and CARPS), Cobitidae (loaches), and Catostomidae (suckers).Mercuric Chloride: Mercury chloride (HgCl2). A highly toxic compound that volatizes slightly at ordinary temperature and appreciably at 100 degrees C. It is corrosive to mucous membranes and used as a topical antiseptic and disinfectant.Manure: Accumulations of solid or liquid animal excreta usually from stables and barnyards with or without litter material. Its chief application is as a fertilizer. (From Webster's 3d ed)Environmental Remediation: Removal of ENVIRONMENTAL POLLUTANTS or contaminants for the general protection of the environment. This is accomplished by various chemical, biological, and bulk movement methods, in conjunction with ENVIRONMENTAL MONITORING.Thiobacillus: A genus of gram-negative, rod-shaped bacteria that derives energy from the oxidation of one or more reduced sulfur compounds. Many former species have been reclassified to other classes of PROTEOBACTERIA.Sodium Cyanide: A highly poisonous compound that is an inhibitor of many metabolic processes and is used as a test reagent for the function of chemoreceptors. It is also used in many industrial processes.Air Pollution, RadioactiveEnvironmental Pollution: Contamination of the air, bodies of water, or land with substances that are harmful to human health and the environment.Ammonia: A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.Air: The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Brassica: A plant genus of the family Cruciferae. It contains many species and cultivars used as food including cabbage, cauliflower, broccoli, Brussel sprouts, kale, collard greens, MUSTARD PLANT; (B. alba, B. junica, and B. nigra), turnips (BRASSICA NAPUS) and rapeseed (BRASSICA RAPA).Selenium: An element with the atomic symbol Se, atomic number 34, and atomic weight 78.96. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Drug Resistance, Microbial: The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).