Nonessential trace element

The trace elements include all inorganic elements found in living systems at very low concentration (picograms to micrograms per gram of cells or wet tissue). Some trace elements are essential for normal health and development others are toxic and still others have not been shown to be either. Chemically similar elements may compete for intestinal or cellular uptake or for metal binding sites on metalloenzymes and proteins. Interactions may also be complementary or synergistic. 

Many nonessential trace elements are found in the body. Depending on the local environment, at least 43 elements are normally incorporated into developing teeth another 25 elements are seen less frequently. The rest, notably the heavy metals, have never been detected in teeth. Many trace elements, particularly the heavy metals, are considered when testing for metal poisoning. Many plants concentrate essential and nonessential elements from soil and water, including aluminum (several species of subtropical plants), selenium (many plants), strontium (mesquite beans), and lithium (wolfberries, used by Native Americans in the southwestern United States for jam). Ingestion of these plants can cause toxicity for the element involved. 

Cadmium, a waste product from several industrial processes, is the cause of itai-itai ( ouch-ouch ) disease, which is characterized by osteomalacia with painful fractures of affected, bones and by nephropathy with an excretory pattern similar to that seen in Fanconi s syndrome. In 

Trace Elements Thought to Be Essential in Animals and Humans  

Impairment of growth and reproduction (several species) heart damage and decreased plasma triacylglycerol (goats) plasma amino acid changes. 

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As a ubiquitous nonessential trace element with chemical similarities to calcium, strontium appears to have low toxicity. In vitro studies demonstrate that stable strontium can substitute for calcium in biological... 

Liebscher, K. and Smith, H. (1968). Essential and nonessential trace elements. A method of determining whether an element Is essential or nonessentlal In human tissue, Arch, Environ. Health 17, 881-890. 

The importance of the basal medium in culturing normal cells was demonstrated by Dr. Richard Ham (Ham and McKeehan, 1979). Dr. Ham s laboratory developed a number of different types of culture media, in which the concentrations of the individual nutritional components have been optimized to support the growth of specific types of normal, differentiated cells. The most widely used is nutrient mixture FI2, which contains nonessential, as well as essential, amino acids, a number of lipids, and trace elements (Table 5). 

A. A. Momen, G. A. Zachariadis, A. N. Anthemidis, J. A. Stratis, Development and validation of routine analysis methods for the determination of essential, nonessential, and toxic minor and trace elements in cereal and cereal flour samples by inductively coupled plasma atomic emission spectrometry, Int. J. Assoc. Off. Anal. Chem., 88 (2005), 1797-1810. 

Figure 10.9. Concentration profiles of phosphate, silicate, and dissolved trace elements in open oceans. Fe, Ni, Cd, Zn, and Cu show characteristic surface depletion resulting from uptake by algae. (Cd is nonessential but may be taken up the same way as nutrients.) (Data on iron are from Martin et al., 1989 others from Bruland and Franks, 1983.) (Adapted from Morel and Hering, 1993.)...

Zinc plays an important role as an essential trace element in all living systems from bacteria to humans. The detection of the zinc metalloenzymes and their biological role gradually proved to be a substantial contribution to a better understanding of zinc metabolism and its interactions with other essential and nonessential trace metals. 

Iodine is an essential trace element for animals, including humans, but is considered nonessential for plants (Brady and Weil, 1996). It is ubiquitous in the biosphere (Sheppard et ai, 1994), and is capable of transferring between all three soil phases (solid, liquid and gaseous). Thus, its mobility away from the soil body in the liquid and gaseous phases has important implications in... 

Copper interacts with numerous compounds normally found in natural waters. The amounts of the various copper compounds and complexes present in solution depend on water pH, temperature, and alkalinity and on the concentrations of bicarbonate, sulfide, and organic ligands. In animals, copper interacts with essential trace elements such as iron, zinc, molybdenum, manganese, nickel, and selenium and also with nonessential elements including silver, cadmium, mercury, and lead interactions may be either beneficial or harmful to the organism. The patterns of copper accumulation, metabolism, and toxicity from these interactions frequently differ from those produced by copper alone. Acknowledgment of these interactions is essential for understanding copper toxicokinetics. 

Essential and Nonessential Metals. It is well known that elements in the biological systems may vary a great deal in their concentration from organ to organ and from species to species, but for the purpose of this chapter, the following classification of elemental concentrations has been adopted (17) major, > 1% minor, 0.10-1% micro, 0.01-0.1% trace, 0.01-0.001% ultratrace, < 0.001%. Since total copper in the average, "standard man (18) is approximately 150 mg (2), its classification would fall between trace and ultratrace concentration. However, as is the case with any other element, what is a trace in one organ may be an ultratrace in another, but for serum copper concentration, which is about 100 /xg%, the definition of copper as an ultratrace metal by the above classification may not be justifiable. If the criteria of the "standard man is taken into account, however, the definition seems appropriate. 

Many of the trace metals occur in animals in quantities that reflect the contact of the animal with its environment. It has been suggested that the essential elements can be distinguished from nonessential elements by observing the distribution patterns... 

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