Toxic metals, biologically

Heavy metals with no known biological function, such as aluminum, arsenic, lead, and mercury, are nonessential metals.4-5 These metals are toxic because they can irreversibly bind to enzymes that require metal cofactors. Toxic metals readily bind to sulfhydryl groups of proteins.6-7 In fact,... 

An evaluation of the fate of trace metals in surface and sub-surface waters requires more detailed consideration of complexation, adsorption, coagulation, oxidation-reduction, and biological interactions. These processes can affect metals, solubility, toxicity, availability, physical transport, and corrosion potential. As a result of a need to describe the complex interactions involved in these situations, various models have been developed to address a number of specific situations. These are called equilibrium or speciation models because the user is provided (model output) with the distribution of various species. 

Hammond, P. B. Foulkes, E. C. (1986). Metal ion toxicity in man and animals. In Metal Ions in Biological Systems, ed. H. Sigel, pp. 157-200. New York Marcel Dekker. 

Martin RB (1986) Bioinorganic chemistry of metal ion toxicity. In Sigel H (ed) Concepts on Metal Ion Toxicity (Metal Ions in Biological Systems), vol 20. Marcel Dekker, New York p21-65... 

Copper Hemocyanrn/Tyrosinase Models Copper Proteins with Dinuclear Active Sites Copper Proteins with Type 1 Sites Copper Proteins with Type 2 Sites Cytochrome Oxidase Electron Transfer Reactions Theory Long-range Electron Transfer in Biology Metal Ion Toxicity Metal-related Diseases of Genetic Origin Metallochaperones Metal Ion Homeostasis Nutritional Aspects of Metals Trace Elements. 

It IS proposed that the term "heavy metals" be abandoned in favor of a classifeation which separates metals. .. according to their binding preferences. . . related lo atomic properties.. . A review of the roles of metal ions in biological sysicms demonstrates the potential of the proposed classification for interpreting Ihe biochemical basis for metal-ion toxicity.. . . ... 

At least 11 metals are biologically toxic, as shown in Table I along with their threshold limit values (1,2,3) arsenic, beryllium, bismuth, cadmium, mercury, nickel, lead, antimony, selenium, tin, and vanadium. For these and other metals, the biological toxicity for long-term, low-level exposures is not known. Other metals such as manganese and iron are... 

While heavy metals (i.e., chromium, copper, nickel) are not typical pollutants in a pharmaceutical waste water stream, removal becomes an issue in some segments of the industry, namely chemical intermediates. These streams are generally treated at the process source in order to minimize the waste water volume. Also, heavy metal streams must be treated prior to any biological treatment that the waste water also requires. Since heavy metals are toxic to microorganisms (even at very low concentrations), their presence reduces biological treatment efficiency. 

Toxic metal compounds ° Heavy metals ° Biological waste... 

In every form of heavy metals, the acid soluble phase is the most active. It controls the distribution of heavy metals in sediments-pore waters and their availability. The difference between acid-volatile sulfide and simultaneous extracted metals (AVS-SEM) was investigated to explain the biological toxicity of zinc in the sediments to benthic organisms (Han et al., 2003). When the molar difference between SEM and AVS (i.e., SEMzn-AVS) was <0 pmol/g, the concentration of zinc in the sediment interstitial water was low and few toxic effects were observed. Conversely, when SEM n-AVS exceeded 0 pmol/g, a dose-dependent increase in the relative concentration of zinc in the pore water was detected and apparent toxic effects in the organisms were observed. 

Groundwater quality (biological, metals, and toxic contamination, eutrophication," add deposition," sedimentation)... 

Detrimental metals are toxic at all concentrations because they impair the regular course of life functions. Detrimental effects of metals in biological systems occur primarily through metal-protein interactions. Toxic metals... 

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