Plants, terrestrial copper

Herbicides are chemicals used to destroy unwanted plants (terrestrial or aquatic) called weeds. Herbicides fall into two broad categories inorganic (e.g., copper sulfate, sodium chlorate, and sodium arsenite) and organic (e.g., chlorophenoxy compounds, dinitrophenols, bipyridyl compounds, carbamates, and amide herbicides). Historically, inorganic compounds were the first available and the first used. There has been over a long period a continuous effort to develop herbicide compounds that are more selective—that affect weeds, as opposed to desirable plants. 

In terrestrial vegetation, copper is usually less than 35 mg/kg DW except near smelters, where it may approach 700 mg/kg DW, and in copper-accumulator plants that may normally contain as much as 13,700 mg/kg DW (Table 3.3). In aquatic vegetation, copper is elevated in metals-con-taminated water bodies, reaching concentrations as high as 1350 mg/kg DW in eelgrass (Zostera spp.) from contaminated bays vs. 36 mg/kg DW in conspecifics from reference sites (Table 3.3). 

Adverse effects of copper deficiency can be documented in terrestrial plants and invertebrates, poultry, small laboratory animals, livestock — especially ruminants — and humans. Data are scarce or missing on copper deficiency effects in aquatic plants and animals and in avian and mammalian wildlife. Copper deficiency in sheep, the most sensitive ruminant mammal, is associated with depressed growth, bone disorders, depigmentation of hair or wool, abnormal wool growth, fetal death and resorption, depressed estrous, heart failure, cardiovascular defects, gastrointestinal disturbances, swayback, pathologic lesions, and degeneration of the motor tracts of the spinal cord (NAS 1977). 

Table 3.4 Effects of Copper on Representative Terrestrial Plants and Invertebrates Organism, Copper Concentration or Dose,...

Copper discharges to the global biosphere are due primarily to human activities, especially mining, smelting, and refining copper and the treatment and recycling of municipal and industrial wastes. Some copper compounds, especially copper sulfate, also contribute to environmental copper burdens because they are widely and intensively used in confined geographic areas to control nuisance species of aquatic plants and invertebrates, diseases of terrestrial crop plants, and ectoparasites of fish and livestock. 

Numerous and disparate copper criteria are proposed for protecting the health of agricultural crops, aquatic life, terrestrial invertebrates, poultry, laboratory white rats, and humans (Table 3.8) however, no copper criteria are now available for protection of avian and mammalian wildlife, and this needs to be rectified. Several of the proposed criteria do not adequately protect sensitive species of plants and animals and need to be reexamined. Other research areas that merit additional effort include biomarkers of early copper stress copper interactions with interrelated trace elements in cases of deficiency and excess copper status effects on disease resistance, cancer, mutagenicity, and birth defects mechanisms of copper tolerance or acclimatization and chemical speciation of copper, including measurement of flux rates of ionic copper from metallic copper. 

Copper in Plants and Animals. As early as 1818 C. F. Bucholz detected copper in vegetable ash (170, 169). In 1850 F. J. Malaguti and his collaborators detected it in several species of Fucus taken near Saint-Malo (170). The normal presence of copper in organized nature being today a fact generally admitted, said they, one may conclude that if terrestrial plants imbibe this metal from the soil, the Fucus must obtain... 

Effects of copper on representative terrestrial plants and invertebrates... 

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. 

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