Metal uptake by organisms


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Metal uptake by organisms

  1. 1. Metal uptake by organisms
  2. 2. Maryum Atique m.phil chemistry university of Agriculture FSD
  3. 3. Introduction History Uptake mechanism Metals and their effect
  4. 4. Metals A metal is a solid material (an element, compound, or alloy ) that is typically hard, opaque, shiny and features good electrical and thermal conductivity.
  5. 5. Kinds of metals Alkali metals Alkaline earth metals Metalloids Heavy metals • Lithium(Li), sodium(Na), potassium(K), rubidium(Rb), cesium(Cs), francium(Fr) • Beryllium(Be),magnesium(Mg), calcium(Ca), strontium(Sr), barium(Ba), radium(Ra) • Boron, silicon, germanium, arsenic, antimony, tellurium and polonium • platinum, silver(Ag), gold, copper(Cu), nic kel(Ni), chromium(Cr), iron(Fe), lead(Pb), cadmium(Cd), mercury(Hg)
  6. 6. Heavy metals The term heavy metal refers to any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations.
  7. 7. Heavy metals Macro-nutrient elements • Cobalt(Co), copper(Cu), Zinc(Zn), iron(Fe) Micro-nutrient elements • Copper(Cu), nickel(Ni), chromium(Cr), iron(Fe) Highly toxic elements • Cadmium(Cd), lead(Pb), silver(Ag), mercury(Hg) Precious elements Precious elements • platinum, silver(Ag), gold
  8. 8. Sources of heavy metal pollution Mining Metallurgical industry Smelting Sources Fossil fuel combustion Corrosion Agriculture and forestry Waste disposal
  9. 9. History The most important disaster by heavy metals
  10. 10. Minamata sandoz chemical spill Spill mining waste water Spain Itai-itai
  11. 11. Minamata disaster • 1932Minamata Sewage containing mercury is released by Chisso's chemicals works into Minimata Bay in Japan. The mercury accumulates in sea creatures, leading eventually to mercury poisoning in the population. • 1952Minamata Syndrome In 1952, the first incidents of mercury poisoning appear in the population of Minimata Bay in Japan, caused by consumption of fish polluted with mercury, bringing over 500 fatalities. Since then, Japan has had the strictest environmental laws in the industrialised world.
  12. 12. Minamata disease Minamata disease , is a neurological syndrome caused by severe mercury poisoning
  13. 13. Sandoz chemical spill The Sandoz chemical spill was a major environmental disaster on November 1, 1986 caused by a fire at a chemical factory Sandoz near Basel, Switzerland, sending tons of toxic chemicals into the nearby river Rhine and turning it red. The chemicals caused a massive mortality of wildlife downstream, killing among other things a large proportion of the European eel population in the Rhine, although the situation subsequently recovered within a couple of years. The stored chemicals included, beside urea and fluorescent dye, organophosphate insecticides,mercury compounds and organochlorides.
  14. 14. Spill mining wastewater Spain 1998 In april 1998 a sudden burst in a chemical reservoir send a stream of water contaminated by, zinc, lead and cadmium into the Guadiamar river system. Experts estimate that Europe's largest bird sanctuary, as well as Spain's agriculture and fisheries, will suffer permanent damage from the pollution
  15. 15. Itai-itai itai-itai disease was the documented case of mass cadmium poisoning in Toyama Prefecture, Japan starting around 1912. The cadmium poisoning caused softening of the bones and kidney failure. The disease is named for the severe pains caused in the joints and spine. The cadmium was released into rivers by mining companies in the mountains. The mining companies were successfully sued for the damage. Itai-itai disease is known as one of the Four Big Pollution Disease of Japan The term "itai-itai disease" was coined by locals
  16. 16. Respiratory Absorption a. Metal may be inhaled as vapor or aerosol (fume or dust particulate) Fume or vapor of some metals & compound are readily absorbed in from alveolar space (cadmium, mercury, tetraethyl lead) b. Large particles trapped in upper respiratory tract, cleared by mucociliary transport to pharynx and swallowed (equivalent to oral exposure) c. Small particles may reach alveolar/gas exchange. Water soluble metal aerosols are rapidly absorbed from alveoli into the blood
  17. 17. Gastrointestinal Absorption 1)Metal may introduce into GI tract through food, water, mucociliary clearance. 2)Metal are absorbed into the cells lining the intestinal tract by: Passive or facilitated diffusion Specific transport process Pinocytosis It depends on many factors  Solubility of metal in fluids of the intestinal tract  Chemical forms of metal (lipid soluble methyl mercury is completely absorbed compare to inorganic mercury – poorly absorbed)  Presence and composition of other materials in GI tract  Composition for absorption sites between similar metals (zinc & cadmium or calcium & lead)  Physiological state of the person exposed (Vitamin D enhance the absorption of lead)
  18. 18. Kidney - Important route of excretion 1) Metals in blood plasma are bound to plasma proteins and amino acids 2) Metals bound to low molecular weight proteins and amino acids are filtered in glomerulous into fluid of the renal tubule 3) Some metals (Cd & Zn) are effectively resorbed by tubular epithelia before they reach the urinary bladder where very little resorption occur.
  19. 19. Excretion Enterohepatic Circulation Absorbed metal may also excreted into intestinal tract in bile, pancreatic secretion or saliva Minor Pathways        Hair (Hg, Zn, Cu and As) Nails Saliva Perspiration Exhaled air Lactation Exfoliation of skin
  20. 20. General mechanism of metal Induced oxidative stress
  21. 21. Heme Biosynthesis Succinyl-CoA+Glycine (delta-aminolevulinate synthetase) delta-Aminolevulinate (delta-aminolevulinate dehydratase) Porphobilinogen Heme Pb
  22. 22. Phytoremediation Phytoremediation is the use of plants to clean up a contamination from soils, sediments, and water. This technology is environmental friendly and potentially costeffective. Plants with exceptional metal-accumulating capacity are known as hyperaccumulator plants . Phytoremediation takes the advantage of the unique and selective uptake capabilities of plant root systems, together with the translocation, bioaccumulation, and contaminant degradation abilities of the entire plant body.
  23. 23. Mechanism of heavy metal uptake by plants through phytoremediation technology 1) Phytostabilization 2) Rhizodegradation 3) Phytodegradation 4) Phytoextraction 5) Phytovolatilization
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