http://netedu.xauat.edu.cn/jpkc/netedu/jpkc2009/szylyybh/content/wlzy/1/Review%20of%20Arsenic%20in%20natural%20water%20-%20Smedly.pdf

A review of the source, behaviour and distribution of arsenic in natural waters

Soil pH is probably the single most informative measurement that can be made to determine soil characteristics. At a single glance, pH tells much more about a soil than merely indicating whether it is acidic or basic. For example, availability of essential nutrients and toxicity of other elements can be estimated because of their known relationship with pH. The term pH was "invented" by the Swedish scientist Sorensen (1909) in order to obtain more convenient numbers and the idea quickly caught on. Gillespie and Hurst (1918) seem to have been among the earliest to determine pH (or PH, as it was then called) electrometrically using a platinum-palladium blackhydrogen gas electrode, a calomel reference electrode and a fairly cumbersome potentiometer and galvanometer system. At that period, it was still much more common to use colorimetric methods with indicator dyes than the electrometric method. This changed rapidly, however. Sharp and Hoagland (1919) used a similar but less involved method than Gillespie and Hurst (1918) and Healy and Karraker (1922) used a commercially available platinum-hydrogen gas electrode, potentiometer and galvanometer which had been designed by Clark (1920). The decade of the 1920s saw the development of the quinhydrone electrode which was less fragile and much less expensive than the hydrogen-platinum electrode. But, it was the development of the glass electrode in the 1930s that brought the determination of pH very rapidly to its present importance and convenience. The Beckman Model G pH meter (circa 1931) was practically indestructible and could be used as a portable as well as a laboratory instrument. Although it was cumbersome by today's standards, it was virtually foolproof (except for the constantly failing batteries) and many are still capable of operating if not actually operating today. As recently as two decades ago, the use of the small, handheld portable pH meters then available to determine pH in the field was a very imprecise and hazardous undertaking because both electrodes and meters were subject to sudden failures but this has changed rather abruptly in the last few years. Microcircuitry and plastic have contributed to rugged pH meters and electrodes that withstand

Soil pH and Soil Acidity

Arsenic in the Soil Environment: A Review

Hydrogeochemistry of arsenic and other inorganic constituents in groundwaters from La Pampa, Argentina

Arsenic geochemistry and health

Arsenic Solubility in a Reduced Environment1

Reactivity of Montmorillonite Surfaces with Weak Organic Bases1

Diffusion of Zinc in Soils as a Function of Applied Zinc, Phosphorus, and Soil pH1

Phosphorus Diffusion in Soils: I. The Effect of Applied P, Clay Content, and Water Content1

Adsorption of Aldicarb By Clays and Soil Organo-Clay Complexes1

Allen R. Swoboda

Papers

Arsenic Solubility in a Reduced Environment1

Reactivity of Montmorillonite Surfaces with Weak Organic Bases1

Diffusion of Zinc in Soils as a Function of Applied Zinc, Phosphorus, and Soil pH1

Phosphorus Diffusion in Soils: I. The Effect of Applied P, Clay Content, and Water Content1

Adsorption of Aldicarb By Clays and Soil Organo-Clay Complexes1