Arsenicals treatment

The results of one research programme indicate that copper-chromium-arsenic treatments are not corrosive towards galvanised steel and stainless steel in the moisture content range 15-22%. 

Attention focused on inorganic arsenical pesticides after accumulations of arsenic in soils eventually became toxic to several agricultural crops, especially in former orchards and cotton fields. Once toxicity is observed, it persists for several years even if no additional arsenic treatment is made (Woolson 1975). Poor crop growth was associated with bioavailability of arsenic in soils. For example, alfalfa (Medicago sativa) and barley (Hordeum vulgare) grew poorly in soils con-... 

US Environmental Protection Agency US EPA (2002b) Arsenic Treatment Technologies for Soil, Waste, and Water. EPA-542-R-02-004. Office of Solid Wastes and Emergency (5102G). 

General design of precipitation/coprecipitation systems for arsenic treatment in water... 

As discussed in Chapter 3, at least trace amounts of arsenic commonly occur in rocks, soils, sediments, sludges and spent sorbents from water treatment systems, coal ashes, industrial wastes, and many other natural and artificial solids. Depending upon whether they are considered regulatory hazards (Appendix E), solid materials may require treatment before disposal (waste management) or remediation if they are located at a contaminated site. For solids, arsenic treatment may involve reducing the arsenic concentrations in the materials so that they are no longer hazardous (for example, soil washing). However, because arsenic cannot be destroyed, eventually the element will require permanent disposal in a manner that does not... 

Chen, H.-W., Frey, M.M., Clifford, D. et al. (1999) Arsenic treatment considerations. Journal of American Water Works Association, 91(2-3), 74-85. 

Arsenate A mineral, compound, or aqueous species containing AsC>43, where the valence state of the arsenic is pentavalent (As(V)). Arsenate is often abbreviated As(V) in the literature, especially in documents dealing with arsenic treatment. The inorganic arsenic acid species, EUAstTu and HAsC>42, are the most common dissolved forms of arsenate in near / H neutral aqueous solutions (compare with arsenite and thioarsenate). 

About 65-90 percent of heavy metals such as lead, cadmium, and arsenic are retained in the melt. The fugitive arsenic is captured in the offgas treatment system, treated by standard arsenic treatment technology (unspecified), and returned to the next melt (Osborne, 2003, p. 3). 

Didecyldimethylammonium chloride is used to prevent stain and mildew on freshly cut lumber81 If a quaternary ammonium salt monomer could be impregnated into wood, then graft polymerized to it, the process might displace some of the chromium copper arsenate treatments. Some antibacterial polymers (e.g., 4.9) work by gradual hydrolysis to release the active group.82... 

It is possible that this or a similar compound could be used to replace the copper-chromium arsenate treatment now used on wood. Carvacrol is fairly volatile, bp 237°C. It would be interesting to see how fast it would be released from wood treated with it under pressure. If it is released too fast for purposes of preservation, the wood could be im-... 

After long-term exposure to arsenic, treatment with dimercaprol and penicillamine also may be used, but oral penicillamine alone usually is sufficient. The duration of therapy is determined by the clinical condition of the patient, and the decision is aided by periodic determinations of urinary arsenic concentrations. Adverse effects of the chelating agents may limit the usefulness of therapy. Dialysis may become necessary with severe arsenic-induced nephropathy successful removal of arsenic by dialysis has been reported. 

Brady P.V., Teter D.M., Khandaker N.R., Krumhansl J.L., Siegel M.D. Development of novel arsenic treatment approaches. SAND2004-0056, Sandia National Laboratories, Albuquerque, NM 2004. 

H-W Chen, MM Frey, D Chfford, LS McNeill, M Edwards. Arsenic treatment considerations. J Am Water Works Assoc 91(3) 74-85, 1999. 

Arsenic in drinking water supplies can be removed by a variety of treatment processes including those cited in Table 1, which also lists the typical applications of each process. All these processes do a much better job of removing As(V) compared with As(III). Thus, before using these processes, it will often be necessary to oxidize As(in) to As(V) using chlorine or an alternative oxidant. This chapter focuses arsenic treatment by metal-oxide adsorption (MOA), ion exchange (IX), and iron (III) coagulation-microfiltration (C-MF), because these processes have proven to be the most efficient and cost effective in bench- and pilot-scale studies, especially for point-of-use (POU), point-of-entry (POE), wellhead, and small community treatment systems. 

DA Clifford and M Wu. Arsenic treatment technology demonstration Predicting the effect of water quality on arsenic adsorption by activated alumina. Report to the Montana State University Water Resources Center, 2001. 

Unnikrishnan D et al Torsades de pointes In 3 patients with leukemia treated with arsenic trioxide. Biood 2001 97(5) 1514-1516. [PMID 11222403] (Torsade de pointes in 3 ot 19 patients, after 42,16, and 12 days of Intravenous arsenic treatment two cases were fatal.)... 

Hering j. G. and Chu V. Q. (1998) The chemistry of arsenic treatment implications of arsenic speciation and occurrence. Presented at the AWWA Inorganic Workshop, San Antonio, TX, February 23 -24. 

Ultrastructural studies of sections of embryonic Balb/c mice at 7 hr after an intraperitoneal injection of 45 or 60 mg/kg sodium arsenite in the dam revealed dense-stalnlng inclusions within the neuroepithelium. The inclusions had disappeared at 21 hr, but extracellular dilatations and intracellular vesicles - said to be portions of the endoplasmic reticulum - were present and remained at up to 44 hr after arsenate treatment (Morrissey and Mottet, 1981). 

USEPA (2003) Arsenic treatment technology evalrration handbook for small systems. H.A.E.C. Division, Washington, DC. 

Figure 6.10. Optimal pH ranges for arsenic treatment technologies (adapted from USEPA, 2003).

---