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Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
Metal uptake by organisms
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  • 1. Topic: Metals uptake by organisms By Maryum Atique M. Phill chemistry University of Agricylture, FSD
  • 2. 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.
  • 3. Properties • are natural components of the Earth's crust • they cannot be degraded or destroyed • to a small extent they enter our bodies via food, drinking water and air • as trace elements, some heavy metals (e.g. copper, • selenium, zinc) are essential to maintain the metabolism of the human body • however, at higher concentrations they can lead to poisoning • heavy metal poisoning could result, for instance, from drinking-water contamination (e.g. lead pipes), high ambient air concentrations near emission sources, or intake via the food chain
  • 4. Bioaccumulation • Bioaccumulation is the “build-up of chemicals or heavy metals in living organisms”. • The chemical accumulates because it does not break down easily (decomposers can’t break them down) • The chemicals get stored in fat-cells of organisms and can cause serious problems...
  • 5. Mercury Hg • Mercury is the only common metal which is liquid at ordinary temperatures. It rarely occurs free in nature and is found mainly in cinnabar ore (HgS) in Spain and Italy. • It alloys easily with many metals, such as gold, silver, and tin - these alloys are called amalgams. Its ease in amalgamating with gold is used in the recovery of gold from its ores.
  • 6. • • • • Health effects of mercury Disruption of the nervous system Damage to brain functions DNA damage and chromosomal damage Allergic reactions, resulting in skin rashes, tiredness and headaches
  • 7. • Acidic surface waters can contain significant amounts of mercury • When the pH values are between five and seven, themercury concentrations in the water will increase due to mobilisation of mercury in the ground • Once mercury has reached surface waters or soils microorganisms can convert it to methyl mercury, a substance that can be absorbed quickly by most organisms and is known to cause nerve damage
  • 8. Cadmium Cd
  • 9. Sources of Cadmium  Cadmium is used as an electrode in “nicad” batteries  Cadmium is used as a pigment in paints(yellow color)  It is also used in photovoltaic devices and in TV screens  Cigarette smoke  Fertilizers and pesticides Note: The greatest proportion of our exposure to cadmium comes from our food supply- seafood, organ meats, particularly kidneys, and also from potatoes, rice, and other grains.
  • 10. HEALTH EFFECTS • Human uptake of cadmium takes place mainly through food • Diarrhoea, stomach pains and severe vomiting • Bone fracture • Damage to the central nervous system • Damage to the immune system • Psychological disorders • Possibly DNA damage or cancer development
  • 11. Environmental effects of cadmium • Cadmium can be transported over great distances when it is absorbed by sludge and can pollute surface waters as well as soils • Cadmium strongly adsorbs to organic matter in soil • When cadmium is present in soils it can be extremely dangerous, as the uptake through food will increase • Soils that are acidified enhance the cadmium uptake by plants • This is a potential danger to the animals that are dependent upon the plants for survival – Cadmium can accumulate in their bodies, especially when they eat multiple plants. e. g: cow
  • 12. Chromium - Cr • Chromium(III) is an essential nutrient for humans and shortages may cause heart conditions, disruptions of metabolisms and diabetes • But the uptake of too much chromium(III) can cause health effects as well, for instance skin rashes
  • 13. HEALTH EFFECTS • When it is a compound in leather products, it can cause allergic reactions, such as skin rash • After breathing it in, chromium(VI) can cause nose irritations and nosebleeds • Upset stomachs and ulcers • Respiratory problems • Weakened immune system • Kidney and liver damage • Alteration of genetic material • Lung cancer • Death
  • 14. Environmental effects of chromium • Most of the chromium in air will eventually settle and end up in waters or soils • Chromium in soils strongly attaches to soil particles and as a result it will not move towards groundwater • In water chromium will absorb on sediment and become immobile
  • 15. Lead - Pb • Foods such as fruit, vegetables, meats, grains, seafood, soft drinks and wine may contain significant amounts of lead • Cigarette smoke also contains small amounts of lead
  • 16. Lead sources • • • • application of lead in gasoline fuel combustion industrial processes solid waste combustion
  • 17. Health effects of lead • Disruption of the biosynthesis of haemoglobin and anemia • A rise in blood pressure • Kidney damage • Disruption of nervous systems • Brain damage • Diminished learning abilities of children • Behavioural disruptions of children, such as aggression, impulsive behaviour and hyperactivity
  • 18. Environmental effects of lead • Soil functions are disturbed by lead intervention, especially near highways and farmlands, where extreme concentrations may be present • Also soil organisms are suffered from lead poisoning
  • 19. Arsenic • Arsenic oxides were the common poisons used for murder and suicide from roman times through to the middle ages • Arsenic compounds were used widely as pesticides before the organic chemicals era • Arsenic is very much similar to phosphorous
  • 20. Sources of Arsenic  Pesticides  Mining, smelting of gold, lead, copper and nickel  Production of iron and steel  Combustion of coal  Leachate from abandoned gold mines  Used as a wood preservative  Herbicides  Tobacco smoke  Wallpaper paste and pigments in wallpaper
  • 21. Health effects  Birth defects  Carcinogen: Lung cancer results from the inhalation of arsenic and probably also from its ingestion. Skin and liver cancer, and perhaps cancers of the bladder and kidneys, arise from ingested arsenic  Gastrointestinal damage  Severe vomiting  Diarrhea  Death •Causes arsenic keratosis of skin
  • 22. Arsenic in drinking water in US
  • 23. General sources of heavy metals in residential houses • Infiltration from outside, along with the dust carried on shoes and clothes • Indoor sources include old-lead and latex based paints, domestic water supply, burning of wood, and tobacco smoke • Pesticides and fungicides are major sources of arsenic and mercury indoors
  • 24. Methods for measurement of trace metals  Most common method of collecting particulate matter is through filters  Identification and concentration of individual trace metals like lead, cadmium, arsenic, mercury and chromium is determined by  Atomic absorption spectrophotometer  X-ray fluorescence  Atomic absorption spectrophotometry is a destructive method and requires at least 1 to 2 ml of solution  X-ray fluorescence is a nondestructive method and works independent of the chemical state of the sample.
  • 25. Control strategies
  • 26. Control methods • Periodic vacuuming of the house can be effective in removal of these pollutants • Replacement of wood-burning by an equivalent gas or electrical appliance • Removal of old lead and mercury-based paints • The effective method for removal of mercury vapors is by the use of packed bed of absorbents • Gold-coated denuder can also be used for the removal of mercury from air

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