Arsenic flux

Some studies have reported conservative behavior during estuarine mixing. In the unpolluted Krka Esmary of Yugoslavia, Seyler and Martin (1991) observed a linear increase in total arsenic with increasing salinity, ranging from 0.13 xgL in freshwaters to 1.8 JLgL offshore. Other studies however, have observed nonconservative behavior in estuaries due to processes such as diffusion from sediment pore waters, co-precipitation with iron oxides, or anthropogenic inputs (M. O. Andreae and T. W. Andreae, 1989 Andreae et al., 1983). The flocculation of iron oxides at the freshwater-saline interface as a result of increase in pH and salinity can lead to major decrease in the arsenic flux to the oceans (Cullen and Reimer, 1989). 

A synonym for orpiment according to Terry (1893) and Weber (1923). However, Salter (1869) states that arsenic yellow Called also Mineral Yellow, has improperly been classed as an orpiment, from which it differs in not being a sulphide, and in containing lead. It is prepared from arsenic fluxed with hfriarge, and reduced to a powder. This suggests that it was a lead arsenic oxide, perhaps analogous to lead-tin and lead-antimony oxides (FitzHugh, 1997). 

Impurities ate elirninated in fire refining in the foUowing sequence slag, that is, oxides of iron, magnesium, aluminum, and sihcon fluxing, that is, arsenic and antimony and vapors, that is, sulfur (as SO2), cadmium, and zinc. 

The As (arsenic) concentration of seawater is controlled by input of rivers, sedimentation on the seafloor, weathering of the seafloor, exchange between atmosphere and seawater, volcanic gas input, and hydrothermal input. Previous studies on the geochemical cycle of As have not taken into account the hydrothermal flux of As. Therefore, hydrothermal flux of As from back-arc, island arc and midoceanic ridges to ocean is considered below. 

Geochemical balance of arsenic in ocean and subduction flux (g/year) (Shikazono, 1993)... 

Shikazono, N. (1993) Influence of hydrothermal flux on arsenic geochemical balance of seawater. Chikyuka-gakii (Geochemistry), 27. 135-139 (in Japanese). 

Copper smelting Copper concentrate, siliceous flux Sulfur dioxide, particulate matter containing arsenic, antimony, cadmium, lead, mercury, and zinc Acid plant blowdown slurry/sludge, slag containing iron sulfides, silica... 

The neutron activation method for the determination of arsenic and antimony in seawater has been described by Ryabin et al. [66]. After coprecipitation of arsenic acid and antimony in a 100 ml sample of water by adding a solution of ferric iron (10 mg iron per litre) followed by aqueous ammonia to give a pH of 8.4, the precipitate is filtered off and, together with the filter paper, is wrapped in a polyethylene and aluminium foil. It is then irradiated in a silica ampoule in a neutron flux of 1.8 x 1013 neutrons cm-2 s 1 for 1 - 2 h. Two days after irradiation, the y-ray activity at 0.56 MeV is measured with use of a Nal (Tl) spectrometer coupled with a multichannel pulse-height analyser, and compared with that of standards. 

Unlu, M.Y. and S.W. Fowler. 1979. Factors affecting the flux of arsenic through the mussel Mytilus gallopro-vincialis. Mar. Biol. 51 209-219. 

Smith, J. A., A. K. Trisdale, and H. J. Cho, Quantification of natural vapor fluxes of trichlorethene in the unsaturated zone andPicatinny Arsenal, New Jersey , Environ. Sci. Technol., 30, 2243-2250 (1996). 

The removal of small quantities of arsenic from metals and ores is a commercial problem which may be mentioned at this point. The Harris process of softening lead,6 used in several refineries, is based on the principle that such impurities as arsenic, antimony and tin may easily be oxidised and in the presence of certain alkali salts can he converted into arsenates, antimonates and stannates. Certain fluxes, such as sodium nitrate, sodium hydroxide, sodium chloride or lead oxide, are added to the molten lead, the presence of an oxidising agent and an alkali salt being essential. The alkaline slag obtained is fused 7 and... 

Bashkin, V.N. and Wongyai, K. (2002) Environmental fluxes of arsenic from lignite mining and power generation in northern Thailand. Environmental Geology, 41(8), 883-88. 

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