Arsenic origin

When diets that contained 11-88 mg/kg arsenic originating from the incorporated roxarsone were fed to layer hens for 4 weeks, arsenic residues in liver, eggs, and the excreta significantly increased with increasing arsenic levels in feeds (4). 

In a notorious case in Manchester in 1900-1901 6000 people were affected by drinking beer containing 15 p.p.m. arsenic 70 people died as a result. The arsenic originated from sulfuric acid containing 1.4% arsenious acid, produced from As-containing iron pyrites. This sulfuric acid was used in a process to manufacture glucose for the brewers, and the glucose contained several hundred parts per million arsenic. 

At least in the recent past, the Waikato River and other streams in New Zealand have had excess arsenic (Aggett and Aspell, 1979). For the Waikato River, the arsenic originated from both natural sources and a... 

Figure 14. Case study 1 contaminated situations. Geographic distribution of arsenic contents in different environmental compartments of the Malcantone area, Ticino /Switzerland soils, river sediments and aquatic mosses. Data from this study. State Laboratory, Canton Ticino, and Martini and Fillet (1996).The whole area is naturally contaminated with arsenic originating from numerous smaller and larger ore deposits dominated by Fe, As, Zn, Pb and Sb (indicated with black spots). The general background of As in the till material forming the aquifers varies between 50 and 150 ppm, but locally values up to 500 ppm occur.

Most dietary arsenic originates from fish, shellfish, and seaweed products. On the basis of the U.S. Food and Drug Administtation (FDA) Total Diet Study for Market Baskets collected from 1990 through 1991, Adams et al. (54) estimated that food conttibuted 93% of the total daily intake of arsenic, with seafood accounting for 90%. The major arsenic species found in the fish and shellfish that are usually eaten is arsenobetaine (AB), a ubiquitous major arsenic species... 

The formation of the blue arsenomolybdic complex has been studied by /CorofeJ " (unpublished), who found that in the absence of phosphate after a reaction time of 30 min, less than 24 % (both in pure water and seawater) of the arsenate originally present had reacted. However, the reaction speed was catalysed by phosphate ions, and even at 0.5 pmol/L phosphate all the msenate may react. The effect of arsenic can be eliminated by reduction to arsenite as given in Section 10.2.6. 

Rosaniline or magenta was originally obtained by oxidising with arsenic acid a mixture of aniline with 0- and />-toluidine. The product was then lixiviated and treated with common salt, which converted the ai senate into the hydrochloride of rosaniline. Pararosaniline was prepared in a similar way fiom a niixtuie of aniline and /-toluidine. The series... 

Original Special Primers supplied by Frankford Arsenal Correction made for oxygen in primer cup, anvil, and paper... 

Most of these compounds were originally prepared by liquid-phase epitaxy. That process is now largely replaced by MOCVD, particularly in the case of gallium arsenide, gallium arsenic phosphide, and gallium aluminum phosphide. 

This scheme accounts for both the induced oxidation of iodide (where ci = 2) and that of manganese(ri) (where ci = 0.5) without including step (19). Furthermore it can be seen that in the presence of iodide the rate of disappearence of chromate will not be altered, whilst the rate of oxidation of arsenic(III) will be reduced to one-third of its original value, as found experimentally. 

It was published in the 17th Century from a badly damaged, hand written manuscript by Lintaut. It was later republished in 1978 in old (or Medaeval) French. The original printing is listed in the Arsenal Library under No. 3020. The later version was found and translated by Dr. Wilson... 

Origin Sample Copper Arsenic Antimony Silver Lead Reference... 

The precipitation of arsenic with H2S gas in the normal condition could occur only in strongly acidic medium whereas another cation of the second group Cd(II), precipitates only in faintly acidic medium, therefore, the precipitation of both cadmium and arsenic with H2S gas in the same solution was not easily possible. To precipitate both in the same solution, the H2S gas is conventionally first passed into the strongly acidic original solution of basic radicals followed by its bubbling into the diluted solution. To examine the role of ultrasound on the precipitation of arsenic in faintly acidic or neutral medium, few experiments were carried out. The results obtained showed effective precipitation of arsenic even in mild reaction solutions, with their pH ranging from 5.1 to 8.8. under ultrasonic field. Hence Cd2+ and As3+/5+ both could be precipitated in the same solution at low pH under the... 

Arsenic vesicants are rapidly hydrolyzed in water but a lack of solubility may slow the rate of reaction. Arsenic decomposition products are stable and some of them have toxic and/or vesicant properties that nearly equal the original agent. 

---