Significance of Trace Metals

The pathophysiological mechanisms implicated in the occurrence of trace metal deficiency include inborn and genetically determined enzyme defects causing dysfunction in absorption, transport, storage, or excretion, as well as acquired deficiency caused by nutritional deficiency, insufficient intestinal availability, high metal losses (via urine, sweat, blood losses), or interaction of trace metals. Typical clinical symptoms in trace metal deficiency are well known. 

Copper deficiency disorders in pigmentation, retarded growth, anemia in children, disorders in the structure of the arterial walls 

Zinc d ciency inappetence, impaired wound healing, retarded growth, hypogonadism, skeleton abnormalities, acrodermatitis enteropathica Chromium deficiency reduced glucose tolerance 

Manganese deficiency disorders in spermatogenesis, bone abnormalities, reduced serum cholesterol 

Selenium deficiency muscular dystrophy, cardiomyopathy, cardiovascular diseases Vanadium deficiency hypercholesterolemia 

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The editors concept of clinical chemistry, as stated in previous volumes of this serial publication, encompasses a wide field of subjects— from the mechanism of blood coagulation to the microbiological assay of vitamins, and from the significance of trace metals in health and disease to the therapeutic application of increased gas pressure. The natural history of clinical conditions and their comparison with normal controls share one common feature, namely, the central position of some species of molecules, be they small or large, all of them the natural subject of chemical research. Hence, practical methods develop, either manual or mechanized, the results of which become increasingly more useful for the clinician in diagnosis, therapy, and prognosis. 

Rainbow PS (1988) The significance of trace metal concentrations in decapods. Symp Zool Soc Lond 59 291-313. 

Allen HE (1993) The significance of trace metal speciation for water, sediment and soil quality criteria and standards. The Science of the Total Environment, Supplement 1993, Elsevier, 23-45... 

For example, the industrial preparation of mineral acids, such as sulfuric, hydrochloric and nitric, inevitably leads to them containing small concentrations of metals as impurities. If the acid is to be used purely as an acid in a simple reaction, the presence of small amounts of metals is probably unimportant. If, however, the acid is to be used to digest a sample for the determination of trace metals by atomic absorption spectrometry, then clearly the presence of metallic impurities in the acid may have a significant effect on the results. For this latter application, high-purity acids that are essentially metal-free are required. 

We can see that the content of trace metals in water extraction is very low. This means that the direct involvement of these metals in biogeochemical cycles is very restricted. The significant increase of metal contents in acid-soluble form was shown only for Fe, Mn and, partly, for Zn. These data testify the importance of atmospheric deposition for the Arctic ecosystems as a source of nutrients. 

There are significant differences in plant uptake of trace metals from soils. It is one of the most important pathways characterizing the exposure to various elements... 

Measurement of trace metal concentrations can provide fundamental insights into marine geochemical processes. Many metals are important micronutrients in seawater and can play a significant role in upper ocean biogeochemistry and carbon cycling. Under certain conditions, elevated concentrations of metals associated with human activities can have negative impacts on marine ecosystems. 

The data presented in Table 11.1 indicate that the fluvial gross river flux is the major source of trace metals to the oceans and that most of this flux is in particulate form (fluvial gross particulate flux). But the majority of this particulate flux is trapped within estuaries, primarily via settling, and, hence, is not released into the open ocean. As a result, the fluvial net particulate flux is only about 10% of the fluvial gross particulate flux. In seawater, most of this particulate metal remains in solid form due to low solubilities. The particulate metals eventually settle to the seafloor and are subsequently buried in the sediments. In the case of iron, a small fraction of the particulate pool does dissolve. In the surface waters, solubilization of particulate iron can provide a significant amount of this micronutrient to the phytoplankton. 

SrS04>. Carbonate-rich fluoroapatite minerals, such as francolite, are the major component of bones. As noted in Chapter 11, hard and soft parts can contain significant amoimts of trace metals. 

Stevenson F. J. (1983). Trace metal-organic matter interaction in geologic environment. In The Significance of Trace Elements in Solving Petrogenetic Problems and Controversies, S. Au-gustitis, ed. Theophrastus Publications, Athens. 

The Clean Air Act of 1990 has made trace metal content in fuels and wastes the final ash-related compositional characteristic of significance. Considerable attention is paid (ca 1993) to emissions of such metals as arsenic, cadmium, chromium, lead, mercury, silver, and zinc. The concentration of these metals in both grate ash and flyash is of significance as a result of federal and state requirements of particular importance is the mobility of metals. This mobility, and the consequent toxicity of the ash product, is determined by the Toxic Characteristic Leaching Procedure (tclp) test. Tables 8—10 present trace metal contents for wood wastes and agricultural wastes, municipal waste, and refuse-derived fuel, respectively. In Table 8, the specific concentration of various components in the RDF governs the expected average concentration of trace metals. 

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