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Department of Chemistry CHEM1020 General Chemistry *********************************************** PowerPoint Presentation
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Department of Chemistry CHEM1020 General Chemistry ***********************************************

Department of Chemistry CHEM1020 General Chemistry ***********************************************

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Department of Chemistry CHEM1020 General Chemistry ***********************************************

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  1. Department of Chemistry CHEM1020 General Chemistry *********************************************** Instructor: Dr. Hong Zhang Foster Hall, Room 221 Tel: 931-6325 Email: hzhang@tntech.edu

  2. CHEM1020/General Chemistry_________________________________________Chapter 13. (L27)-Chemistry of Water • Today’s Outline …Water quality …Sources of water pollution …Transport and fate of water pollutants

  3. Chapter 13. (L27)-Chemistry of Water • Water quality …Water use classification and water standards A practical evaluation and definition of water quality depends on how the water is used in addition to its chemical composition   The quality of water is not judged by its purity but rather by its suitability for the particular use desired For example, nitrate (NO3-) of >10 ppm in drinking water is considered a potential hazard, particularly to children, but on the other hand, nitrate is a nutrient beneficial to plants; so water of > 10 ppm nitrate may be good one for agricultural use Water use needs to be defined before water quality can be evaluated against

  4. Chapter 13. (L27)-Chemistry of Water • Water quality …Common approach to evaluating water quality -Define the particular purpose of water use -Set numerical standards for physical and chemical characteristics of the various waters of different usages -Field-measure the pertinent water parameters to determine if a particular water source would have a satisfied water quality and suitable for use

  5. Chapter 13. (L27)-Chemistry of Water • Water quality …Typical water use classification -Recreational Class 1. primary contact, surface water that suitable for or intended to become suitable for prolonged and intimate contact with the body, or for recreational activities where the ingestion of small quantities of water is likely to occur, e.g., swimming, rafting, kayaking, water skiing, etc., Class 2. secondary contact, surface water that suitable for or intended to become suitable for recreation in or around the water, which are not included in the primary contact subcategory, e.g., shore fishing, motor yachiting, etc.

  6. Chapter 13. (L27)-Chemistry of Water • Water quality …Typical water use classification -Aquatic life Surface water that suitable for or intended to become suitable for the protection and maintenance of vigorous communities of aquatic organisms and populations of significant aquatic species a. Class 1. Cold water aquatic life (Tw < 20 ˚C commonly) b. Class 1. Warm water aquatic life (Tw > 20 ˚C normally) c. Class 2. Cold and warm water aquatic life. These are waters that are not capable of sustaining a wide variety of cold or warm water biota, including sensitive species, due to conditions of physical habitat, water flows and levels, or uncorrectable water quality that results in substantial impairment of the abundance and diversity of species   -Agriculture For agriculture, not hazardous as drinking water for livestock

  7. Chapter 13. (L27)-Chemistry of Water • Water quality …Typical water use classification -Domestic water supply Surface water that suitable for or intended to become suitable for portable water supply. After receiving standard treatment, i.e., coagulation, flocculation, sedimentation, filtration, and disinfection with chlorine and its equivalent, these waters will meet the federal and sate drinking water standards -Wetlands Surface water and groundwater that supply wetlands Wetlands may be defined as areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and under normal conditions, do not support, a prevalence of vegetation and organisms typically adapted for life under saturated soil conditions

  8. Chapter 13. (L27)-Chemistry of Water • Water quality …Typical water use classification -Groundwater Subsurface waters in a zone of saturation that are or can be brought to the surface of the ground or to surface waters through wells, springs, seeps, or other discharge areas. Domestic use Agriculture use

  9. Chapter 13. (L27)-Chemistry of Water • Water quality Each state has its water quality standards, which can be found from the pertinent state government agency The US EPA sets baseline standards for different use classifications that serve as minimum requirements for the state standards.

  10. Chapter 13. (L27)-Chemistry of Water • Water quality …Water determination Water quality is defined in terms of -Chemical composition: concentration of metals, organic compounds, chlorine, nitrates, ammonia, phosphorous, sulfates, etc. -General physical and chemical properties: T, alkalinity, conductivity, pH, DO, hardness, total dissolved solids (TDS), COD, etc. -Biological characteristics: BOD, fecal coliforms, whole effluent toxicity, etc. -Radionuclides: radium-226, radium-228, uranium, radon, gross alpha and gross beta emissions, etc. Keep updated about the standards

  11. Chapter 13. (L27)-Chemistry of Water • Sources of water pollution ..Point sources Example: industrial discharge ..Non-point sources (diffuse sources) Example: N, P, pesticides, Hg deposition, PCB deposition

  12. Chapter 13. (L27)-Chemistry of Water • Transport and fate of water pollutants Emissions Sedimentation Food web accumulation Bound by humic substances Adsorbed on suspended particles

  13. Chapter 13. (L27)-Chemistry of Water • Major water pollution and pollutants …Heavy metals Examples: Hg, Pb, Cd, Cr, As, Co, etc. …Polychlorinated Biphenyls (PCBs) and Dioxins -Both share similar chemical structures and a range of chemical, biological, and environmental properties   -Trade names of PCBs: Aroclor, Chlophen, Kanechlor, Fenclor -Use: plasticizers, ink -PCB, a mixture of chlorinated biphenyls with different number of Cl -Sources of PCBs, electrical equipment, e.g., capacitors, transformers as heat transfer fluid First recognized as environment problem in 1966

  14. Chapter 13. (L27)-Chemistry of Water • Major water pollution and pollutants Dioxin, or PCDDs, Polychlorinated dibenzo [1,4] dioxins, -dioxins are unwanted byproducts in chemical processes involving chlorine and combustion (incinerators, coal-burning power plants, vehicle exhaust), pulp and paper mills bleaching (use of Cl) -widely distributed in the environment, largely associated with particles in the troposphere TCDD is a highly toxic member of dioxins

  15. Chapter 13. (L27)-Chemistry of Water • Major water pollution and pollutants …Synthetic polymers (plastics, elastomers, synthetic fibers) Plastics, Elastomers, Synthetic fibers   Applications in plumbing, textiles, paint, floor covering, clothing; Environmentally resistant …Petroleum hydrocarbons Long carbon chain of C and H only, 50-90% n-alkanes (normal paraffins, found in all crude oil, C1-C40 or >), branched alkanes, cycloalkanes (largest fraction), aromatics (< 20%) non-hydrocarbons S-containing compounds, in higher boiling fractions N-containing compounds

  16. Chapter 13. (L27)-Chemistry of Water • Major water pollution and pollutants …Pesticides DDT Herbicides Insecticides Fungicides -Chlorohydrocarbons pesticides Toxic to aquatic life and wildlife Neurotoxins (nervous systems), inducing tremors

  17. Chapter 13. (L27)-Chemistry of Water • Major water pollution and pollutants …Detergents and soaps   …Organometallic compounds   …Pharmaceutical products and derivatives Solving water pollution Natural degradation and cycling Cutting the sources Waste water treatment prior to discharge Engineering treatment of aquatic system (e.g., cleaning river beds, Hudson River, NY) Treatment using wetland

  18. Chapter 13. (L27)-Chemistry of Water Quiz Time TBA