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  • 1. Presentation topic: Aqueous Elemental Pollution by Maryum Atique M.Phill chemistry university of Agriculture FSD.
  • 2. Definition of Heavy Metals • Heavy metals are those metal of relatively high density, or high relative atomic weight. • Heavy metal can include elements lighter than carbon and can exclude some of the heaviest metals. • It mainly includes: - Transition - Metals - Some metalloids - Lanthanides - Actinides.
  • 3. COMMON HEAVY METALS CAUSING AQUEOUS POLLUTION • • • • • • • • • • Cadmium Lead Mercury Aluminum Antimony Arsenic Zinc and Copper Nickel Tin Uranium
  • 4. Sources of heavy metals pollution • Primary sources of heavy metals are point sources: - Mines - Foundries - Smelters - Coal-burning power plants - Diffuse sources (combustion by-products and vehicle emissions) • Waste-derived fuels are especially prone to contain heavy metals, so heavy metals are a concern in consideration of waste as fuel. • Electronic waste is also a significant source of heavy metal contaminants
  • 5. Sources and sink of heavy metals
  • 6. Aluminium aqueous pollution • The amount of aluminium in seawater is 0.013 and 5 ppb. River water generally contains about 400 ppb of aluminum. • Regular aluminium concentration is 0.4ppm • Below pH 4.5 solubility increases and concentration becomes upto 5ppm and so its pollution level is also increased.
  • 7. Arsenic water pollution • Arsenic contamination of groundwater is often due to naturally occurring high concentrations of arsenic in deeper levels of ground water • Its sources are geochemical processes, mining activities • Industrial and manufacturing processes. • through the dissolution of minerals and ores, and as a result of erosion from local rocks. • It can causes: • Irritation of the stomach and intestines • Red and white blood cells decreased production, skin changes and lung irritation
  • 8. Severe effects of arsenic pollution
  • 9. Antimony aqueous pollution • Major sources of antimony in drinking water is waste water from petroleum refineries; fire retardants; ceramics; electronics. • It causes lung irritation, heart and lung damage, stomach pains, diarrhea, vomiting and stomach ulcers. • Its elevated level adversely affect the plant growth. • Cadmium aqueous pollution: • Maximum contaminant level for cadmium is 0.005 mg/L or 5 ppb. • Cadmium applications- including electroplating and the manufacture of batteries. • Contaminated foodstuffs can result in emphysema, renal failure, cardiovascular disease, and perhaps cancer.
  • 10. Antimony aqueous pollution
  • 11. Lead aqueous pollution • Action Level for Treatment Technique in parts per million (ppm) Lead = 0.015 ppm • Health Effects Infants and children: Delays in physical or mental development; children could show slight deficits in attention span and learning abilities. Adults: Kidney problems; high blood pressure • Sources of contamination Corrosion of household plumbing systems, erosion of natural deposits. Industrial sources such as lead mining, smelting and coal combustion, the use of lead-based paint and lead containing pipes in water supply systems.
  • 12. Quality Standard for Groundwater Categories of Ground water 1 2 3 4 5 Lead ≤mg/L 0.005 0.01 0.05 0.1 >0.1 Cadmium ≤mg/L 0.0001 0.001 0.01 0.01 >0.01
  • 13. • Category 1 and 2 reflects the low contents of chemical components for groundwater. • Category 3 reflects that it is applicable to concentrative drinking water sources and industrial and agricultural water use. • Category 4 is primarily applicable to the industrial use water and partial agricultural use water. • Category 5 is not applicable for drinking purposes.
  • 14. Mercury aqueous pollution • largest emitters cement plants power plants gold mining, and industrial boilers in • In areas of mercury contamination, larger and older fish tend to have higher levels of mercury. • Minamata disease is a neurological syndrome caused by severe mercury poisoning by polluted water. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision, and damage to hearing and speech
  • 15. Effects of mercury on health
  • 16. Nickel aqueous pollution • The average concentration of nickel in drinking water in the United States is between 2 and 4.3 ppb. • Metallic nickel and some other nickel compounds are teratogenic and carcinogenic to mammals. Nickel concentrations in plants are usually 1 μg/g, and concentrations above 50 μg/g are toxic. • Effects of nickel: • Increased red blood cells (cancer) • Increased protein in the urine • Chronic bronchitis • Reduced lung function • Stomach aches • Cancer of the lungs
  • 17. Uranium aqueous pollution • Uranium is a naturally and commonly occurring radioactive element and found in water coming from power plants causing uranium contained water pollution • Uranium poisoning cause birth abnormalities including physical deformities, neurological and mental disorders. • Copper and zinc: • Zn can lead to acute gastrointestinal and respiratory damages and acute heart, brain and kidney damages, when they are in polluted aqueous form. • High concentrations of these heavy metals in ground water can negatively affect on crop growth, as these metals interfere with metabolic functions in plants • Cupper toxicity in water lead to Liver damage ,Kidney damage ,Neurologic damage, Weakness , Abdominal pain, Nausea, Vomiting, Diarrhea, Lung damage and Coma.
  • 18. Methods to purify the water from elemental pollution
  • 19. Commonly used methods - Chemical precipitation - Biosorption - Ion exchange - Reverse osmosis - Solvent extraction • Reverse Osmosis: It is a process in which heavy metals are separated by a semi-permeable membrane at a pressure greater than osmotic pressure caused by the dissolved solids in wastewater. The disadvantage of this method is that it is expensive.
  • 20. RO CC • Direct contact membrane distillation (DCMD). • Applicable to desalination. Heated seawater is passed along the surface of a hydrophobic polymer membrane. • Evaporated water passes from the hot side through pores in the membrane into a stream of cold pure water on the other side. • The difference in vapour pressure between the hot and cold side helps to push water molecules through.
  • 21. Ion-exchange • Ions exchange: In this process, metal ions from dilute solutions are exchanged with ions held by electrostatic forces on the exchange resin. Different type of ion exchange resins used for every metal like Lead : carboxylic resin Uranium: WBA and SBA • Chemical Precipitation: Precipitation of metals is achieved by the addition of coagulants such as alum, lime, iron salts and other organic polymers. The large amount of sludge containing toxic compounds produced during the process is the main disadvantage.
  • 22. Heavy metals removal by biosorption • The biosorption process involves a solid phase (biological material) and a liquid phase (solvent, normally water) containing a dissolved species to be sorbed. • The degree of sorbent affinity for the sorbate determines its distribution between the solid and liquid phases. • Many algae have immense capability to sorb metals, and there is considerable potential for using them to treat wastewaters
  • 23. Heavy metals removal by Zeolites • Zeolites are nature's powerful detoxifiers that are so strong they even binds all those heavy metals from the food and water we ingest. • natural zeolites can safely remove heavy metals such as mercury, cadmium, lead, arsenic, aluminum, and tin, while also removing radioactive metals like cesium and Strontium-90. • Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents.