PREFACE We must understand the metabolic process before we con

PREFACE We must understand the metabolic process before we con demn the presence of some trace elements with apparently no value. his volume represents perhaps the first effort tofitgeochemistry into environmental science. In studying environmental geochemistry we gain insight into the origin, transition, and concentration of a particular element. Also we may assess the real impact of man-made alterations in natural environments. In fact, the natural cycle of a few elements is altered in smaller environments, but given enough time, they are incor porated back into the whole terrestrial cycle. As the result of this altera tion, anomalous metallic concentrations are discovered near cities, freeways, smelters, powerplants, and industrial sites. Geochemistry is a comparatively young and growing science which studies the chemical composition of the earth. It was pioneered by F. W. Clarke, V. M. Goldschmidt, and V. I. Vernadskii in the late 1920s. Increased growth began with the use of geochemistry as an applied science. Tracing the route and determining the concentration of sub stances or elements is a most important aspect of applied geochemistry. Thefirstapplication was in economic geology and in tracing the origin, age, stability, and transformation of certain biogenic and anthropogenic substances. In the last two decades, anthropogenic emissions of increased amounts of organic substances such as pesticides and other common organic and inorganic pollutants have generated world-wide concern. Emissions enter all three phases: atmosphere, water, and land. They admix and transfer within the phases and during météorologie phenomena such as duststorms, rain, and oceanic breezes. Tracing the origin of each substance or ele ment becomes increasingly difficult as it ages and is affected by dilution factors related to meteorological, erosional, and tectonic phenomena. For example, in air chemistry the origin of certain emissions is established by studying their concentration, chemical or physical transformation, asso ciated particle size, dilution with air or windblown dust, and the transfer mechanism within the different phases. Of biological importance are some elements which in low concen trations foster life, such as boron, copper, zinc, molybdenum, cobalt,

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Kothny; Trace Elements in the Environment Advances in Chemistry; American Chemical Society: Washington, DC, 1973.


selenium. A t higher concentrations, these elements may be toxic. Therefore, it is important to know their concentration i n the natural environment and how these concentrations affect the healthy deployment of life on this planet. Thus, soil chemistry, underground water chemistry, trace element chemistry i n plants, and some areas of oceanography and air pollution are interrelated. Today, most atmospheric toxicants of anthropogenic origin ("pollutants") are organic or generated in the atmosphere by interaction of organic substances with actinic radiation (formation of photochemical smog and ozone). Nevertheless, an important portion of atmospheric toxicants is inorganic, such as sulfur dioxide, carbon oxides, nitrogen oxides, ozone, and sulfuric acid mist. These compounds are the most damaging to plants and humans (chronic bronchiopulmonar diseases). Toxicants in liquid effluents originating from sewage and industrial effluents damage aquatic plants and fish or enter into the food chain of animals and humans. Agricultural sprays and other abatement chemicals add to particulate matter which settles on land plants and may produce chronic" or fatal damage to grazing animals and birds. Some substances become concentrated by biological enrichment through the natural food chain. Combustion and manufacturing processes are responsible for emitting large amounts of S, As, V , Zn, C d , Pb, C u , Se, Sb, H g which form part of the metallic content of particulate matter collected in or near cities. Lead is a known contaminant emitted by automotive vehicles. Particle size segregation is a most important tool used to pinpoint the source of these different toxicants. Geochemical results obtained by studies of mineral exploration, meteorology, oceanography, biochemistry, agriculture, air pollution, and others have been scattered through the meetings of several different societies. The Association of Exploration Geochemists was founded i n 1970 for fostering symposia on that specific subject. The science of trace elements in agriculture is comparatively young and expands constantly as a spinoff of fertilizer chemistry. Most information about trace elements in agricultural soils and their availability to the plants has been obtained in East European countries. In the classical sciences of soil and water chemistry, the study of trace constituents is relatively new. Outstanding work has been accomplished in this area by the U.S. Geological Survey under title of ' T h e Geochemical Series." Two large groups are directly interested in soil and water chemistry. The first is concerned about agricultural production and the second about economic geology, such as petroleum, mineral, and geothermal exploration. Because environmental geochemistry is implicitly but not exclusively a part of the Division of A i r , Water and Waste Chemistry (now changed to Division of Environmental Chemistry), a symposium on that subject viii



was assembled as a part of this Division under the title "Geochemical Cycle of Trace Elements in our Environment." However, this was not thefirstsymposium on geochemistry organized by the American Chem ical Society. A symposium "On Problems in Analytical Geochemistry" was presented at the SE-SW Regional Meeting in Louisiana, December 1970. As a result of the papers presented at the 162nd National Meeting of the American Chemical Society in Washington, D.C. in September 1971, this book was compiled. We sincerely hope that the scattered environmental geochemical information may be combined in the future to broaden the knowledge about the routes of transfer of each constituent, either from natural sources or emitted by human activity and the ultimate effect on biological systems. In publishing these results, a start in this direction has been made which may eventually lead to a fertilization in this line of thought. EVALDO L. KOTHNY

Berkeley, Calif. July 1973

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PREFACE We must understand the metabolic process before we con

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