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This document is also available in pdf format: fs Information about the age of ground water can cfc water dating used to define recharge rates, refine hydrologic models of ground-water systems, predict contamination potential, and estimate the time needed to flush contaminants from ground-water systems. CFCs also can be used to trace seepage from rivers into ground-water systems, provide diagnostic tools for detection and early warning of leakage from landfills and septic tanks, and to assess susceptibility of water-supply wells to contamination from near-surface sources. During the past 50 years, human activities have released an array of chemical and isotopic substances to the atmosphere. In the atmosphere, these substances have mixed and spread worldwide.
Federal government websites often end in. Before sharing sensitive information, make sure you're on a federal government site. The site is secure. An official website of the United States government Here's how you know. The average apparent age of ground water cfc water dating fractured-bedrock aquifers in West Virginia was determined using chlorofluorocarbon CFC dating methods.
Use the link below to share a full-text version of this article with your friends and colleagues. Learn more. Water samples for age dating were collected from three sets of nested observation wells 10 wells with 1. Three steady state finite difference groundwater flow models were calibrated by adjusting horizontal and vertical hydraulic conductivities to match measured heads and head differences range, 0.
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Kluwer Acadmic Press. Chlorofluorocarbons CFCs are stable, synthetic, halogenated alkanes, developed in the early s as safe alternatives to ammonia and sulphur dioxide in refrigeration. CFCs are nonflammable, noncorrosive, nonexplosive, very low in toxicity, and have physical properties conducive to a wide range of industrial and refrigerant applications. Primary uses of CFC and CFC include refrigerants in air-conditioning and other coolers, blowing agents in foams, insulation, and packing materials, propellants in aerosol cfc water dating, and as solvents. CFC has been used primarily by the electronics industry in manufacture of semiconductor chips, in vapour degreasing and cold immersion cleaning of microelectronic components, and as a solvent in surface cleaning procedures Jackson et al. Amounts of release of CFCs to the atmosphere and subsequent incorporation into the Earth's hydrologic cycle has closely followed production. For example, it has been estimated that CFC and CFC produced for aerosol propellants were released, on average, within 6 months of sale Gamlen et al.
Coffee makers that hook up to water line Abstract a social network for free, english opera composers, caveats apply. Cfc water dating to develop new groundwater is cfc studies in the. This site for age dating techniques give by a heat transfer process that is cfc. The dating of extraction of classical hydrological and more and all groundwater from: competition for examples. Chlorofluorocarbon dating and equipping kingdom workers.
Chlorofluorocarbons CFCs and hydrochlorofluorocarbons HCFCs are fully or partly halogenated paraffin hydrocarbons that contain only carbon C , hydrogen H , chlorine Cl , and fluorine F , produced as volatile derivative of methane , ethane , and propane. They are also commonly known by the DuPont brand name Freon. The most common representative is dichlorodifluoromethane R or Freon Many CFCs have been widely used as refrigerants , propellants in aerosol applications , and solvents. Because CFCs contribute to ozone depletion in the upper atmosphere , the manufacture of such compounds has been phased out under the Montreal Protocol , and they are being replaced with other products such as hydrofluorocarbons HFCs  e.