Search results
Results from the WOW.Com Content Network
Print/export Download as PDF; Printable version; In other projects ... Arsenobetaine is an organoarsenic compound that is the main source of arsenic found in fish. [1 ...
The arsenic (As) cycle is the biogeochemical cycle of natural and anthropogenic exchanges of arsenic terms through the atmosphere, lithosphere, pedosphere, hydrosphere, and biosphere. Although arsenic is naturally abundant in the Earth's crust, long-term exposure and high concentrations of arsenic can be detrimental to human health. [1] [2]
Arsenic is also found in food, water, soil, and air. [132] Arsenic is absorbed by all plants, but is more concentrated in leafy vegetables, rice, apple and grape juice, and seafood. [133] An additional route of exposure is inhalation of atmospheric gases and dusts. [134]
He combined a sample containing arsenic with sulfuric acid and arsenic-free zinc, resulting in arsine gas. The gas was ignited, and it decomposed to pure metallic arsenic which, when passed to a cold surface, would appear as a silvery-black deposit. So sensitive was the test that it could detect as little as one-fiftieth of a milligram of arsenic.
Arsenic is a moderately abundant element in Earth's crust, and although many arsenic compounds are often considered highly toxic to most life, a wide variety of organoarsenic compounds are produced biologically and various organic and inorganic arsenic compounds are metabolized by numerous organisms.
The Marsh test treats the sample with sulfuric acid and arsenic-free zinc. Even if there are minute amounts of arsenic present, the zinc reduces the trivalent arsenic (As 3+). Here are the two half-reactions: Oxidation: Zn → Zn 2+ + 2 e − Reduction: As 2 O 3 + 12 e − + 6 H + → 2 As 3− + 3 H 2 O. Overall, we have this reaction:
The compound was characterized by computational and spectroscopic [2] [3] techniques and found to possess a cage-like structure similar to adamantane in which the four methanetriyl carbon bridgeheads are replaced by arsenic atoms and three of the six methylene bridges are replaced by oxygen atoms.
Arsenate is the major arsenic form in oxidizing environments; however, in one study, bacteria from arsenic-contaminated soil at a smelter site was able to reduce As(+5) to As(+3) under anaerobic conditions at arsenic concentration as high as 75 mg/L. [3] Arsenate-respiring bacteria and Archaea have also recently been isolated from a diversity of natural environments, including freshwater ...