Trace Elements in Soils and Plants [antikvár]

FOREWORD Investigations of the chemical properties and environmental interactions of trace elements have increased in number and scope at an astonishing rate in the past 2 decades. This increase was fostered by the almost simultaneous convergence of factors whose importance could not be ignored by scientific establishments, governments, and the population at large. The rapid industrialization of preceding decades, which led to population shifts from rural locations to urban centers, continued unabated worldwide. The concentrations of population led to unnatural concentrations of metals and other trace elements as the energy requirements and abundance of consumer goods became highly localized. These element concentrations however, do not always remain localized, but often are redistributed, even across national or continental boundaries. In a biological world that is adapted to element concentrations that are generally related to crustal abundance, these concentrations were manifest as one aspect of environmental contamination or pollution. At the same time, studies of the essentiality of certain trace elements in plant and animal nutrition emphasized the fine distinction between adequate and toxic concentrations. The awareness of these problems and their effects on the health and well-being of organisms, including man, coincided with the development of the technical means to investigate geochemical properties and relationships more thoroughly and economically in respect to industrial emissions, agricultural practices, and general environmental conditions. This also led to the development of an extensive literature on the abundance and behavior of trace elements in the biosphere. It is appropriate at this stage of progress in the understanding of trace elements in soils and plants to pause and see where we now stand. Trace element research has been worldwide in scope; a summary of this work must, therefore include research results from many countries. The present authors are eminently qualified for making such a synthesis because of their scientific competence in the field of geochemistry and their familiarity with worldwide literature on the subject, especially the literature not readily available to many English-speaking investigators. The trace element data presented in this book follow the sequence of chemical periodicity. These data cover the general geochemical and biochemical properties of trace elements and provide new insights on chemical relationships which influence their environmental behavior. An understanding of what has been accomplished in geochemical research should indicate the direction for future investigations of the intricate relationships of trace elements in soil and plants, and their effects on specific ecosystems and on the biosphere as a whole. Hansford T. Shacklette U.S. Geological Survey Denver, Colorado