Understanding our fragile environment; Lessons from geochemical studies

• DOI: 10.3133/cir1105
• Publication Date: 1993-01-01
• Authors: L.P. Gough; Sigrid Asher‐Boli...; Laurie S. Balistr...; George N. Breit; Thomas J. Casadevall; J.G. Crock; Kimberley I. Cunn...; Joseph S. Duval; James A. Erdman; Barbara M. Erickson; Walter H. Ficklin; Larry L. Jackson; R. K. Kotra; Joel S. Leventhal; J.M. McNeal; William R. Miller; James K. Otton; Douglass E. Owen; Geoffrey S. Plumlee; G.M. Reimer; R.C. Severson; Kathleen S. Smith; Ronald R. Tidball; Robert A. Zielinski
• Keywords: Trace element; TRACE (psycholinguistics)

An understanding of our fragile environment can begin with a recognition the importance certain elements, commonly called "minerals substances" (such as iron and zinc), in lives humans animals soils that support plants. This is well deserved because these elements are essential for life or optimum health an organism. Some such carbon, hydrogen, oxygen, magnesium, potassium, phosphorus required relatively large amounts by organisms. However, others smaller quantities; referred to trace elements. Diseases have been related deficiency about 20 approximately 13 At same time, if other occur quantities great enough, toxicity result. element, any substance, occurs contains concentrations above what considered be background levels may contaminant. When contaminants at potentially harmful organisms, they labeled hazards. Often quantitative difference between toxic very small. For example, element selenium level no less than 0.4 ppm diet cattle but greater 4ppm. Elements survival plants termed essential, while those not nonessential. Trace fluorine, copper, selenium, molybdenum, listed table on page 1 hazardous forms present high levels. Nonessential heavy metals arsenic, lead, mercury, cadmium, chromium usually organisms much lower Depending association nonessential form natural geologic materials organic matter, minerals, adsorbers clays), range from being safe extremely toxic. The elemental composition plants, animals, correlates makeup Earth, has evolved reflecting occurrences. science environmental geochemistry examines interrelationship physical chemical Earth.