Copper arsenates

A major concern when remediating wood-treatment sites is that pentachlorophenol was often used in combination with metal salts, and these compounds, such as chromated copper—arsenate, are potent inhibitors of at least some pentachlorophenol degrading organisms (49). Sites with significant levels of such inorganics may not be suitable candidates for bioremediation. 

Iron, copper, arsenic, and antimony can be readily removed by the above pyrometaHurgical processes or variations of these (3). However, for the removal of large quantities of lead or bismuth, either separately or together, conventional electrolysis or a newly developed vacuum-refining process is used. The latter is now in use in Austraha, BoHvia, Mexico, and the CIS (5). 

The best protection for wood against the attack of decay fungi, insects, or marine borers is obtained by applying preservatives under pressure before installation (61,62). Both oil-type preservatives, such as creosote or petroleum solutions of pentachlorophenol, and waterborne preservatives, such as copper-chrome arsenate and ammoniacal-copper arsenate, are used when wood is to be in direct contact with the ground or in the marine environments. 

Phosphorized deoxidized arsenical copper (alloy 142 (23)) is used for heat exchangers and condenser tubes. Copper-arsenical leaded Muntz metal (alloy 366), Admiralty brass (alloy 443), naval brass (alloy 465), and aluminum brass (alloy 687), all find use in condensers, evaporators, ferrules, and heat exchanger and distillation tubes. The composition of these alloys is Hsted in Table 5. 

The commercial uses of arsenic compounds in 1988, measured in terms of elemental arsenic, are wood (qv) preservatives, 69% agricultural products (herbicides (qv) and desiccants (qv)), 23% glass (qv), 4% nonferrous alloys and electronics, 2% and animal feed additives and pharmaceuticals (qv), 2% (see Feeds AND feed additives). Chromated copper arsenate (CCA) [11125-95-4] is the most widely used arsenic-based wood preservative. The Environmental Protection Agency has, however, restricted the use of arsenical wood preservatives to certified appHcators. 

Wood Preservation. The use of chromium compounds ia wood preservation is largely because of the excellent results achieved by chromated copper arsenate (CCA), available ia three modifications under a variety of trade names. The treated wood (qv) is free from bleeding, has an attractive ohve-green color, and is paintable. CCA is widely used, especially ia treating utility poles, bull ding lumber, and wood foundations. About 62% of all the chromic acid produced ia the United States is consumed by the wood preservation industry (77,167) (see Building materials, survey). 

Native elements, metals, semimetals, nonmetals Gold, silver, copper, arsenic, antimony, bismuth, copper, sulfur... 

Prominent among the heavy metals found in the wastewater generated in the copper sulfate industry are copper, arsenic, cadmium, nickel, antimony, lead, chromium, and zinc (Table 22.11). They are traced to the copper and acids sources used as raw materials. These pollutants are generally removed by precipitation, clarification, gravity separation, centrifugation, and filtration. Alkaline precipitation at pH values between 7 and 10 can eradicate copper, nickel, cadmium, and zinc in the wastewater, while the quantity of arsenic can be reduced through the same process at a higher pH value. 

Origin Sample Copper Arsenic Antimony Silver Lead Reference... 

Lechtman, H. (1991), The production of copper-arsenic alloys in the central Andes Highland ores and coastal smelters , /. Field Archaeol. 18(1), 43-76. 

Tylecote, R. F. and R. F. McKarrel (1978), The Working of Copper-Arsenic Alloys in the Early Bronze Age, Arnold, London. 

From a canal lined with chromated-copper-arsenate wood vs. reference site 150-200 FW vs. 10 FW elevated concentrations were associated with greenish color and higher frequency of histopathology of digestive gland diverticula 29... 

Transfer of copper from wood treated with chromated copper arsenate (CCA) occurs in estuarine algae (Ulva, Enteromorpha), American oysters, mud snails (Nassarius obsoletus), and fiddler crabs (IJca spp. Weis and Weis 1992). Algae, barnacles, andmussels from CCA-treated lumber show elevated concentrations of copper when compared to reference sites. The epibiotic estuarine community that... 

Weis, J.S. and P. Weis. 1993. Trophic transfer of contaminants from organisms living by chromated-copper-arsenate (CCA)-treated wood to their predators. Jour. Exp. Mar. Biol. Ecol. 168 25-34. 

Weis, P., J.S. Weis, and J. Couch. 1993a. Histopathology and bioaccumulation in oysters Crassostrea virginica living on wood preserved with chromated copper arsenate. Dis. Aquat. Organ. 17 41 -46. 

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