Arsenic sources

Limpet, Littorina littorea Soft parts Near arsenic source 11.5 DW 12... 

Figure 2.2-1 illustrates how arsenic wastewater flows through that facility. The first three arsenic sources were thought to be minor and composed of soluble araenic. These waste streams flow directly to the HF preholding tank and are not involved in the Slurry Recovery process. Sample acquisition for these sources required the operator to perform the wash process in a container with graduations on the sides for volume measurement. Samples were taken after the processes were completed. Arsenic analysis waa done on the measured wash solution and with this analysis and the number of ingots or wafers cleaned or etched, a total arsenic contribution was calculated. 

Woessner, W. Moore, J. Johns, C. Popoff, M. Sartor, L. Sullivan, M. Arsenic Source and Water Supply Remedial Action Study, Milltown, Montana Solid Waste Bureau, Montana Department of Health and Environmental Science Helena, MT, 1984. 

The initial decomposition of Ga(CH3)3 involves the loss of methyl radicals (114-121). These methyl radicals can subsequently react with H2 or the arsenic source, such as AsH3, abstract H from an organometallic or hydrocarbon species, or recombine. The reaction with H2 leads to H radicals that can react with the parent organometallic compound to accelerate its decomposition. The following are some of the reactions ... 

A variety of human activities and products may contaminate estuaries with arsenic, including wood preservatives, pesticides, fertilizer manufacturing, mine drainage and wastes, coal utilization, runoff from slags used as road ballast, and arsenical paints from ships (Landrum, 1994 Davis, De Cumou and Eary, 1997), 370 (Pirrie et al., 2002 Mirlean et al., 2003). In some cases, specific arsenic sources cannot be identified (O Reilly Wiese, Bubb and Lester, 1995). Nevertheless, the cycling of arsenic between water and sediments in contaminated estuaries is often similar to cycles in pristine estuaries, open marine environments, and lakes. 

Stream and location Prominent arsenic source(s) PH Arsenic concentration (pg L 1 ) Reference... 

Location Arsenic source(s) favored by the authors Arsenic concentration (mg kg-1)a Reference(s)... 

Craw, D., Chappell, D. and Reay, A. (2000a) Environmental mercury and arsenic sources in fossil hydrothermal systems, Northland, New Zealand. Environmental Geology, 39(8), 875-87. 

Foley and Ayuso (2008) suggest that typical processes that could explain the release of arsenic from minerals in bedrock include oxidation of arsenian pyrite or arsenopyrite, or carbonation of As-sulfides, and these in general rely on discrete minerals or on a fairly limited series of minerals. In contrast, in the Penobscot Formation and other metasedimentary rocks of coastal Maine, oxidation of arsenic-bearing iron—cobalt— nickel-sulfide minerals, dissolution (by reduction) of arsenic-bearing secondary arsenic and iron hydroxide and sulfate minerals, carbonation and/or oxidation of As-sulfide minerals, and desorption of arsenic from Fe-hydroxide mineral surfaces are all thought to be implicated. All of these processes contribute to the occurrence of arsenic in groundwaters in coastal Maine, as a result of the variability in composition and overlap in stability of the arsenic source minerals. Also, Lipfert et al. (2007) concluded that as sea level rose, environmental conditions favored reduction of bedrock minerals, and that under the current anaerobic conditions in the bedrock, bacteria reduction of the Fe-and Mn-oxyhydroxides are implicated with arsenic releases. 

Arsenic source and water supply remedial action study, MUltown, Montana Final report Department of Geology, University of Montana, 448 p. 

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