Selenium mercury and

Gotsis, 0. 1982. Combined effects selenium/mercury and selenium/copper on the cell population of the alga Dunaliella minuta. Mar. Biol. 71 217-222. 

Henny, C.J. and G.B. Herron. 1989. DDE, selenium, mercury, and white-faced ibis reproduction at Carson Lake, Nevada. Jour. Wildl. Manage. 53 1032-1045. 

It is apparent from Table IV that trace elements determined by the x-ray fluorescence method are limited to those occurring in whole coals at concentrations of at least a few parts per million. Elements such as selenium, mercury, and antimony, which are generally present in whole coal at levels below 1 ppm, cannot be determined by this method. The major elements in coal, hydrogen, carbon, oxygen, and nitrogen, cannot be determined by x-ray fluorescence, but this should not inhibit the use of the method for trace and minor element determinations. 

Volcanic smog (known as vog) is a mixture of atmospheric gases and suspended liquid and solid particles. It forms by the reaction of sulfur dioxide and other volcanic gases with atmospheric moisture, gases, dust, and sunlight (Sutton et al, 1997). Vog consists primarily of sulfuric acid and other sulfate compounds, and can contain a variety of heavy metals, including selenium, mercury, and arsenic (Sutton et al, 1997). Laze, a volcanic haze, forms when molten lava flows into the sea and vaporizes seawater (Sutton et al, 1997). It has many of the same characteristics as vog, with the exception that it probably contains higher levels of chloride and hydrochloric acid derived from seawater. 

Work on the superheated water extraction of coal has been carried out, more directed towards possible processes. Sulfur can be extracted from Illinois Basin coal with acidified superheated water [45] to reduce its sulfur content from 6% to Some other elements can also be removed from coal with acidified superheated water, such as arsenic, selenium, mercury and other ash-forming elements [46, 47]. 

The scrubbing liquor is recirculated at the scrubber. A bleed of the scrubbing liquor is required to control the build-up of sulfuric acid, selenium, mercury and other species. This is the so-called weak acid bleed. The volume of this bleed is relatively small. However, it is concentrated since it results from a recirculation loop at the scrubber. Historical data from the Valleyfield operation show that the average concentration of selenium in the weak acid bleed is in the order of 50 mg/1 with peaks up to 180 mg/1 the average mercury concentration is 30 mg/1 (SNC-Lavalin (3)). The concentration of selenium in such a bleed first depends on the specific selenium content of the zinc concentrate being proeessed. It is known that some zinc ore deposits are characterized by high contents of selenium. Unless adequate treatment technologies are available for the removal of selenium fi-om the acid plant effluent, future development of such deposits may encounter environmental obstacles. 

Extraction times in PFE are very short relative to those required by conventional solid-liquid extraction techniques such as Soxhlet extraction and depend on which particular process determines the extraction rate. The extraction times in PFE usually range between 5 and 30 min, but they can be as long as 90 min in highly unfavorable cases such as the extraction of selenium, mercury, and arsenic from coal. 

The weak acid scrubbing liquor is bled from the system to maintain either a preset maximum acidity or a maximum fluorine concentration. Otherwise the bleed will merely be set by the water balance control. This solution also contains lead, zinc and cadmium dissolved from sinter dusts as well as mercury and selenium. Mercury and selenium react to form mercuric selenide, which precipitates and can foul heat transfer surfaces. The presence of selenium can be beneficial in increasing the capture of mercury by the gas scrubbing system. 

Dry chlorine reacts with most metals combustively depending on temperature alurninum, arsenic, gold, mercury, selenium, teUerium, and tin react with dry CI2 in gaseous or Hquid form at ordinary temperatures carbon steel ignites at about 250°C depending on the physical shape and titanium reacts violendy with dry chlorine. Wet chlorine is very reactive because of the hydrochloric acid and hypochlorous acid (see eq. 37). Metals stable to wet chlorine include platinum, silver, tantalum, and titanium. Tantalum is the most stable to both dry and wet chlorine. 

The pure acid does not react in the cold with sulfur, selenium, tellurium, carbon, silver, copper, zinc, iron, chromium, or manganese, but slowly dissolves mercury and tin (20). At higher temperatures, lead, mercury, tin, and sulfur react rapidly, eg ... 

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

The preparation of Pans-1,2-cyclohexanediol by oxidation of cyclohexene with peroxyformic acid and subsequent hydrolysis of the diol monoformate has been described, and other methods for the preparation of both cis- and trans-l,2-cyclohexanediols were cited. Subsequently the trans diol has been prepared by oxidation of cyclohexene with various peroxy acids, with hydrogen peroxide and selenium dioxide, and with iodine and silver acetate by the Prevost reaction. Alternative methods for preparing the trans isomer are hydroboration of various enol derivatives of cyclohexanone and reduction of Pans-2-cyclohexen-l-ol epoxide with lithium aluminum hydride. cis-1,2-Cyclohexanediol has been prepared by cis hydroxylation of cyclohexene with various reagents or catalysts derived from osmium tetroxide, by solvolysis of Pans-2-halocyclohexanol esters in a manner similar to the Woodward-Prevost reaction, by reduction of cis-2-cyclohexen-l-ol epoxide with lithium aluminum hydride, and by oxymercuration of 2-cyclohexen-l-ol with mercury(II) trifluoro-acetate in the presence of ehloral and subsequent reduction. ... 

Bowerman WW, Evans ED, Giesy P, Postupalsky S. 1994. Using feathers to assess risk of mercury and selenium to bald eagle reproduction in the Great Lakes region. Arch Environ Contam Toxicol 27 294-298. 

Cuvin-Aralar M, Furness R. 1990. Tissue distribution of mercury and selenium in minnows, Phoxinusphoxinus. Bull Environ Contam Toxicol 45 775-782. 

Hoffman DJ, Heinz GH. 1998. Effects of mercury and selenium on glutathione metabolism and oxidative stress in mallard ducks. Environ Toxicol Chem 17 161-166. 

Scheuhammer AM, Wong AEI, Bond D. 1998b. Mercury and selenium accumulation in common loons (Gavia immer) and common mergansers (Mergus merganser) from eastern Canada. Environ Toxicol Chem 17 197-201. 

Sepulveda MS, Poppenga RH, Arrecis JJ, Quinn LB. 1998. Mercury and selenium concentrations in free-ranging in tissues from double-crested cormorants (Phalacrocorax auritus) from southern Florida. Colonial Waterbirds 2T35M2. 

Wayland M, Gilchrist HG, Marchant T, Keating J, Smits JE. 2002. Immune function, stress response, and body condition in Arctic-breeding common eiders in relation to cadmium, mercury, and selenium concentrations. Environ Res 90 47-60. 

It is now well established that organometallic compounds are formed in the environment from mercury, arsenic, selenium, tellurium and tin and hence were also deduced on the basis of analytical evidence for lead, germanium, antimony and thallium. Biological methylation of tin has been demonstrated by the use of experimental organisms. Methylgermanium and methyllead were widely found in the environment but it is debatable whether germanium and lead are directly methylated by biological activity in natural environment. 

Dietz, R., F. Riget, and P. Johansen. 1996. Lead, cadmium, mercury and selenium in Greenland marine animals. Sci. Total Environ. 186 67-93. 

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