Nutrient requirements Copper

Paracelsus (1493-1541) once said dosis facit venenum , meaning toxicity is determined by the amount . For example, the heavy metal copper is an essential nutrient required by the body and cannot be considered as a poison at low concentrations, and yet it is a poison at higher concentrations, causing lysis of red blood cells, vomiting and diarrhoea. Similarly, common table salt is an essential ingredient for life, but becomes quite toxic at high levels of intake. 

Nutrients required by crops can be divided up into major elements and micro (trace) elements (Table 4.2). Micro (trace) elements include boron, copper, iron, manganese, molybdenum, zinc and cobalt, some of which are dealt with later in this chapter. 

It is clear from the data in Table 3 that depletion can be a significant factor which affects the ability of mineral soils to meet the nutrient requirements of plants with respect to molybdenum, boron and copper and that when the total soil levels of these elements are low, crop requirements can only be met for limited periods. For example, an acre of soil containing only 1 ppm boron cannot possibly produce more than 100 tons of crop dry matter with a content of 10 ppm boron. In practice, the boron content is likely to be around 40 ppm in the dry matter and this would limit the total possible yield on such a soil to 25 tons of crop dry matter. Deficiency conditions involving these elements are therefore inevitable within decades on cultivated land, if no steps are taken to replace cropping losses. Deficiency problems involving manganese and cobalt, on the other hand, are more likely to be due to a reduction of availability in the soil than to depletion of the total soil reserves. 

The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

Copper is one of the twenty-seven elements known to be essential to humans (69—72) (see Mineral nutrients). The daily recommended requirement for humans is 2.5—5.0 mg (73). Copper is probably second only to iron as an oxidation catalyst and oxygen carrier in humans (74). It is present in many proteins, such as hemocyanin [9013-32-3] galactose oxidase [9028-79-9] ceruloplasmin [9031 -37-2] dopamine -hydroxylase, monoamine oxidase [9001-66-5] superoxide dismutase [9054-89-17, and phenolase (75,76). Copper aids in photosynthesis and other oxidative processes in plants. 

Enhanced biorestoration is a means by which naturally occurring processes are deliberately manipulated to increase or enhance the rate of cleanup. Biological activity in the subsurface is controlled by the availability of one or more of the necessary metabolic requirements such as an electron acceptor or nutrient. Although electron acceptors are most often the limiting factor, inadequate availability of nitrogen, phosphorus, or micronutrients (such as potassium, copper, or even vitamins) can restrict optimum restoration. When the proper balance of these factors is established, the rate of chemical degradation is maximized. 

Although the toxicity of metallic copper is very low, many copper(II) salts may have varying degrees of toxicity. Inhalation of dusts, mists or fumes of the metal can cause nasal perforation, cough, dry throat, muscle ache, chills and metal fever. Copper in trace amounts is a nutritional requirement, used metaholically in plant and animal enzymes and other biological molecules. It can be either a toxicant or a nutrient within a concentration that may be in the same order of magnitude. 

Several elements, particularly zinc and copper, could play a role as trace nutrients for phytoplankton. They are known to be important for growth of terrestrial plants, but neither the requirement for these nutrients nor the elemental distributions in seawater are well known. The biological availability of both zinc and copper is controlled by their complexation with organic material. Analytical methods that have the distinction of being able to discriminate chemical forms of the metal are needed. These measurements reflect the chemical reactivity and biological availability or toxicity of the metal more accurately. 

MOLYBDENUM (In Biological Systems). Molybdenum is required in very low amouni.s by both plants and animals Nutrient imbalances involving molybdenum and copper have caused serious problems in cattle and sheep production. 

The plants that were the precursors of the coal required a range of elements as nutrients or for stmctural support. Elements essential to plant metabolism include phosphoms, potassium, sulfur, calcium, and magnesium. Some plants also require boron, chlorine, copper, iron, manganese, molybdenum, and zinc (Severson and Shacklette, 1988). Plants may contribute inorganic constituents... 

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