21 Water Quality Parameters

21 Water Quality Parameters - Freshwater and Freshwater...

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Unformatted text preview: Freshwater and Freshwater Pollutants http://www.npr.org/templates/story/story.php?storyId=6100179 Water Pollution "any biological, chemical, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses." 44% of lakes, 37% of rives unsafe for recreation due to toxic water pollutants 32% of estuaries. Basic Types of Pollution 1) Biological 2) Physical 3) Chemical Biological Water Pollution Develops from microorganisms and their activities. Biological Pathogens Pathogen: An agent of disease. An infectious organism Bacteria Typhoid Cholera Viruses Hepatitis Polio Protozoa Parasites poliovirus Schistosomiasis Amoebic dysentery Giardiasis giardia Biological Pollution: Microbial Metabolism Metabolic activities of otherwise benign microorganisms can significantly alter surface water quality Discharge of organic material to surface water increases microbial activity Sources of Organics human waste animal waste food operations meat packing plants medical facilities Physical Pollutants Physical Pollutants Heat electric power plants – O2, thermal shock ½ of water withdrawn in the U.S. Warm water holds less O2 Physical Pollutants Sediment chokes and fills lakes, reservoirs erosion, deforestation, agriculture, building and road construction Turbidity and reduction of the euphotic zone Sediment particles harbor pathogens and pollutants Chemical Pollutants Nutrients Pesticides Metals Salts Organics Chemical Pollutants Nutrients Nitrogen NO3NH4+ Phosphorus HPO4-2 H2PO4- Animal Wastes, Agricultural Runoff, Sewage Discharge, OSWT Nutrient additions stimulate primary productivity Primary production is the production of organic compounds from carbon dioxide and chemical nutrients through the process of photosynthesis CO2 + H2O + light = CH2O + O2 Photoautotrophs Form the base of the food chain Organic compounds formed by Primary Producers provide energy to consumers (Heterotrophic Organisms) Primary Productivity All life on earth is directly or indirectly reliant on primary production. In terrestrial ecosystems, these are mainly plants, while in aquatic ecosystems algae and phytoplankton are primarily responsible. Excess Nutrients Over-stimulate Primary Productivity Wastewater Agriculture Urban Decreased light penetration Decreased oxygen content Changes in species diversity Heavy Metals and Metalloids Arsenic Erosion of natural deposits; pesticide waste, runoff from glass & electronics production wastes, treated lumber, groundwater Mercury Erosion of natural deposits; discharge from refineries and factories; runoff from landfills, coal burning Lead Corrosion of household plumbing systems; natural deposits, paint, fuels, electronics Mercury, Arsenic, and Lead Lead found in blood sample from 1 of 10 Washingtonians Arsenic found in urine samples from 4 of 10 Washingtonians Mercury found in hair samples from 10 of 10 Washingtonians Chemical Pollutants Petroleum three to six million metric tons Spills account for about 5% of petroleum entering waterways. oil changes, bilge cleaning and ship maintenance, recreational boating. New emission standards In 2006 (EPA) Exxon Valdez - 300,000 birds and 2,500 otters were killed Chemical Pollutants Synthetic Organic Chemicals Pesticides Industry Solvents/Cleaning Flame Retardants DDT PCBs/Dioxin TCE /PCE PBDE Potentially highly toxic Persistent in the environment http://www.npr.org/templates/story/story.php?storyId=6100179 Basic Types of Pollution 1) Biological 2) Physical 3) Chemical Extra Credit: 1. An example of physical pollution is __________ 2. An example of chemical pollution is __________ 3. Identify the 2 most important nutrients indicated 4. Identify one metal of concern in water. From where do pollutants come? Two Basic Avenues of Water Pollution Non-point source pollution Diffuse sources Difficult to trace, regulate Point source pollution Specific entry point Industrial discharges Sewage treatment plants Landfills Non-point Source Pollution Lawns, Gardens Golf Courses Agriculture Urban Runoff Golf Courses Fertilizers Pesticides Animal Wastes Oil, gas, rubber Agriculture Urban In 1987 the Clean Water Act was reauthorized with additional provisions to address a new source of pollution, urbanization Point Source Pollution Factories/Industry Wastewater Treatment Landfills Underground Storage Tanks Mines Industry and Wastewater treatment Often located near waterways (pollute and dilute) 80% of point source river pollution Contaminant Plumes Landfills Prior to the 1970s Dissolved pollutants = leachate Paint, solvents, oil, cleaning agents Underground Storage Tanks Gasoline, solvents Steel – corrosion - Leaking Butler Plaza Butler Plaza was formerly the location of the Stengal Airfield, founded in 1942. Gainesville In 1985, the DEP conducted a groundwater contamination source identification study for volatile organic contamination (VOC) found in two private wells in a residential area. They were contaminated with trichloroethylene (TCE) and perchloroethylene (PCE). The supply wells were shut down and all areas were hooked to city water. Evaluation of groundwater monitoring data indicated that the Floridan aquifer had been impacted by VOC contamination in two areas. According to the groundwater investigation reports, the primary source of the chlorinated solvent-related groundwater contamination is in the vicinity of one of the old airfield hangers formerly located at a spot covered by the Butler Plaza. Two Basic Avenues of Water Pollution Non-point source pollution Diffuse sources Difficult to trace, regulate Point source pollution Specific entry point Industrial discharges Sewage treatment plants Industry Landfills USTs Example Point and Non-Point Pollution Superior Huron Ontario Michigan Erie Shallowest of the Great Lakes average depth = 62 feet Buffalo agriculture Detroit Cleveland Largest population density of Great Lakes Point and Non-Point Source Pollution Industrial Chemicals Heavy Metals Petroleum Nutrients Pesticides Non-point Source Pollution Nitrogen and Phosphorus Blue-green algae phytoplankton Stimulation of Primary Productivity Agriculture, Wastewater Discharge, Urban Runoff Point Sources lip papillomas Petroleum Organic Chemicals Heavy Metals Pesticides Petrochemicals Cuyahoga River Fire (1969) Petrochemicals Cuyahoga River Fire (1969) Clean Water Act: 1972 Determining Water Quality Pollutant Types Biological (Pathogens) Metals (Hg, Pb, As) Nutrients (N, P) Organic Chemicals (PCBs, Dioxins) Sediment Heat Major Determinants of Water Quality and the Impact or Availability of Water Pollutants Organisms Solubility Oxygen pH Biological (Pathogenic/non pathogenic) Metals (Hg, Pb, As) Nutrients (N, P) Organic Chemicals (PCBs, Dioxins) Sediment Heat Microorganisms Pathogenic – harmful Non-pathogenic - benign The Earliest Organisms Autotrophic: produce complex organic compounds from simple inorganic molecules and an external source of energy. Organic = Carbon-containing Chemoautotrophs, Cyanobacteria, Plants Autotrophs – Plants, Algae, Cyanobacteria Produce complex organic compounds from carbon dioxide using energy from light. energy light 6CO2 + 6H2O simple inorganic molecule C6H12O6 + 6O2 complex organic compound Primary producers – base of the food chain Heterotrophs Derive energy from consumption of complex organic compounds produced by autotrophs Autotrophs store energy from the sun in carbon compounds (C6H12O6) Heterotrophs consume these complex carbon compounds for energy autotrophs carbon compounds (C6H12O6) Heterotrophs Organisms Heterotrophs: use carbon compounds for energy - consumers Heterotrophs Anaerobic Aerobic live in low-oxygen environments live in high oxygen environments Aerobic heterotrophs Anaerobic heterotrophs Aerobic Heterotrophs and Anaerobic Heterotrophs Aerobic Heterotrophs Live in high-oxygen environments Consume organic compounds for energy Obtain the energy stored in complex organic compounds by combining them with oxygen C6H12O6 + Oxygen = energy Aerobic Respiration C6H12O6 + 6O2 → 6CO2 + 6H2O + energy The energy is obtained by exchanging electrons during chemical reactions. Electron poor Electron rich C6H12O6 + 6O2 → 6CO2 + 6H2O Electron rich Electron poor 2880 kJ of energy is produced Aerobic respiration is very efficient, yielding high amounts of energy Anaerobic Heterotrophic Organisms Live in low-oxygen environments Consume organic compounds for energy Can use energy stored in complex carbon compounds in the absence of free oxygen The energy is obtained by exchanging electrons with elements other than oxygen. Nitrogen (NO3) Sulfur (SO4) Iron (Fe3+) Aerobic Respiration Electron poor Electron rich C6H12O6 + 6O2 → 6CO2 + 6H2O Electron poor Electron rich Anaerobic respiration Electron poor Electron rich C6H12O6 + 3NO3- + 3H2O = 6HCO3- + 3NH4+ Electron rich Electron poor Anaerobic respiration is less efficient and produces less energy. C6H12O6 + 6O2 → 6CO2 + 6H2O C6H12O6 + 3NO3- + 3H2O = 6HCO3- + 3NH4+ C6H12O6 + 3SO42- + 3H+ = 6HCO3- + 3HS- 2880 kJ 1796 kJ 453 kJ The oxygen status of water determines the type of organisms aerobic or anaerobic High-oxygen Low-oxygen Oxygen status also impacts availability and toxicity of some pollutants Solubility The ease with which substances dissolve in water Sodium Chloride is extremely soluble in water NaCl Na+ + Cl- The solubility of other ionic salts varies KCl CaCO3 HgCl2 PbCO3 FePO4 soluble somewhat soluble soluble poorly soluble poorly soluble The degree to which contaminants can exist in water is often determined by their solubility Solubility can be influenced strongly by factors such as pH and oxygen content Solubility The form in which contaminants can exist in water is often determined by their solubility HgCl2 PbCO3 FePO4 soluble poorly soluble poorly soluble Solubility can be influenced strongly by factors such as pH and oxygen content Many toxic organic pollutants including pesticides, and industrial products are extremely insoluble in water. DDT Dioxins PCBs Ironically their insolubility in water is partly responsible For their persistence in the environment. Gases Also Dissolve in Water Gases Gas dissolution 380 ppm CO2 Solubility = 1.69 g/L Between 1800 and 1994, the ocean removed about 118 billion metric tons Of CO2 from the atmosphere. Middle Ages Industrial Revolution 48 percent of all fossil fuel emissions Oxygen is also water Soluble In natural systems, oxygen diffusing from the atmosphere and from plant photosynthesis dissolves in water O2 O2 Diffusion of O2 from the atmosphere is generally slow Reduced oxygen levels Oxygen is being used faster than it can be replaced Oxygen content of water is temperature-dependent Example: Eutrophication Nutrient Additions Nutrient addition increases primary productivity (algae) Sunlight is limited at greater depth Photosynthetic life O2 bacteria Photoautotrophs die and become food for aerobic heterotrophs Aerobic autotrophs consume oxygen Oxygen content in water is reduced If oxygen is reduced sufficiently, aerobic microbes cannot survive, and anaerobic microbes take over Respiration and Still Ponds O2 Aerobic heterotrophs consume oxygen NO3- Heterotrophic Organisms Anaerobic heterotrophs Use nitrate instead of O2 oxygen SO4-2 SO4-2 Anaerobic heterotrophs Use sulfate instead of O2 HS- C6H12O6 + 3SO42- + 3H+ = 6HCO3- + 3HS- Temperature and Oxygen The solubility of oxygen in water is highly temperature dependent. Saturated Oxygen Content 10.1 mg/L 8.3 mg/L 15oC 25oC Affects species diversity Fish Species Minimum Oxygen Tolerances Cold water species: 5-6 mg/L Cool water species: 4 mg/L Warm water species: 2-3 mg/L Trout Pike Bass, Catfish, Bluegill Heat also increases Biological activity Slow diffusion of oxygen Warm Water High biotic activity High demand on oxygen Decreased oxygen content Oxygen contents can affect the form, solubility, or toxicity of important contaminants Oxygen Oxygen is water soluble, but its solubility is temperature-dependent. In the atmosphere, about one out of 5 molecules is oxygen; in water, about one out of every 100,000 molecules is oxygen. Oxygen enters the water body from the atmosphere (slowly) and from photosynthesis near the surface Higher temperatures decrease the ability of water to hold or contain O2. Oxygen leaves the water column principally by organism respiration. Higher temperatures increase biotic activity, decreasing oxygen Oxygen status affects microbial populations and other species diversity as well as the availability or toxicity of important water contaminants. pH pH (hydrogen) H+ ion Elements have equal numbers of protons (+) and electrons (-) Ions are stable forms of elements that result from gaining or losing electrons in chemical reactions Cations have lost electrons and are positively charged Anions have gained electrons and are negatively charged H+, Na+, K+, Ca2+, NH4+, Mg+2 Cl-, F-, NO3-, CO32-, SO42- pH is based on the abundance of hydrogen ions in water When elemental hydrogen loses its electron it becomes a positively charged ion. 1 Electron (-) Nucleus 1 Proton (+) Hydrogen ions participate in enormous numbers of environmental reactions Common Acids Hydrochloric Acid Sulfuric Acid Nitric Acid Carbonic Acid Acetic Acid Ammonium HCl H2SO4 HNO3 H2CO3 HC2H3O2 NH4+ Dissociation of acids HCl H+ + Cl- HNO3 H+ + NO3- H2SO4 H+ + HSO4- pH A measure of the amount of Hydrogen ions in water - Log (H+) Low pH = High amount of Hydrogen ions in water High pH = Low amount of Hydrogen ions in water Low pH: acidic pH (hydrogen) Natural rainfall has a pH of 5.6 H+ Acid: any substance which increases the hydrogen ion concentration in water. - Log (H+) Low pH = High H+ pH 4 = 0.0001 g H+/ L pH 2 = 0.01 g H+/ L There is 100 times more H+ in water at pH 2 compared to pH 4 Availability and Form of Nutrients NH4+ NH3 Low pH High pH High H+ conc. low H+ conc. CaHPO4 + H+ = Ca2+ + H2PO4Solid (unavailable) Dissolved (available) Availability and Form of Metals PbCO3 + H+ Solid (unavailable) Pb2+ + HCO3dissolved (available) Dissolution of metals increases their mobility Mine Tailings There are approximately 420,000 abandoned mines in the states of California, Arizona and Nevada Cd, Pb, Zn, Cr, Cu, Al FeS2 oxygen water PbCO3 + H+ solid 2H2SO4 2H+ + SO42Pb2+ + HCO3soluble Direct toxicity plus dissolution of associated metal contaminants such as arsenic, lead, and cadmium pH and Acid Rainfall Natural rainfall is acidic: pH 5.6 CO2 + H2O = H2CO3 H2CO3 => H+ + HCO3Acid Pollution by sulfur dioxide and nitrogen oxides contributes additional acidity to rainfall. SO2 + H2O → H2SO4 National Surface Water Survey (EPA) Investigated the effects of acidic deposition in over 1,000 lakes Acid rain caused acidity in 75 percent of the acidic lakes and about 50 percent of the acidic streams Most lakes and streams have a pH between 6 and 8. In the Northeast U.S. many lakes have pH less than 5. Adirondacks and Catskill Mountains mid-Appalachian highlands Little Echo Pond has a pH of 4.2. The Canadian government has estimated that 14,000 lakes in eastern Canada are acidic. Low pH can be directly toxic to fish and other species As acid rain flows through soils in a watershed, aluminum is released Low pH and increased aluminum levels cause chronic stress that may not kill individual fish, but leads to lower body weight and smaller size and makes fish less able to compete for food and habitat. Acid tolerances food At pH 5, most fish eggs cannot hatch Increasing acidity End Lecture 18 Top Sources of Groundwater Contamination USTs Landfills Septic Systems Organic Chemicals Petroleum Solvents Cleaning agents Everything Nitrogen/Phosphorus Metals Organics (BOD) Next: Pollutants Determining Water Quality Basic Water Quality Parameters Biological Metals Nutrients Organic Chemicals Turbidity Temperature/Dissolved O2 pH Salinity pH pH (hydrogen) H+ Acid: any substance which increases the hydrogen ion concentration in water. Low pH = High H+ pH 2 = 0.01 g H+/ L pH 8 = 0.00000001 g H+/ L Availability and Form of Nutrients or Metals H2PO4- pH HPO42- Low pH High pH High H+ conc. low H+ conc. Fe, Zn, Mg, Mn, Cu, Al, S, N, Mo Micronutrients and metals generally more available at lower pH Availability and Form of Metals Cr2O3 + 6H+ Insoluble In water 2Cr3+ + 3H2O soluble In water Dissolution of metal oxides increases their mobility Temperature municipal industrial Industrial Cooling asphalt and concrete pavement Temperature Cooling Water Electric Power Primary Metals Chemical and Products Petroleum and Coal Paper and Products Food Machinery Rubber and Plastics Transportation All Other Totals 189.2 billions of m3 153.7 12.8 11.8 4.6 2.30 1.48 0.620 0.484 0.386 1.03 100,0 (%) 81.23 6.76 6.24 2.43 1.21 0.78 0.34 0.26 0.21 0.54 Temperature Poikilothermic Organisms Fish, insects, zooplankton, phytoplankton, bacteria Changes in the growth rates of cold-blooded aquatic organisms and many biochemical reaction rates can often be approximated by a rule which predicts that growth rates will double if temperature increases by 10°C (18°F) within their "preferred" range Increased temperature, however, impacts dissolved oxygen contents. Temperature and Oxygen The solubility of oxygen in water is highly temperature dependent. Oxygen 10.1 mg/L 8.3 mg/L 15oC 25oC Oxygen is water soluble, but its solubility is temperature-dependent. Cold water species: 5 mg/L Cool water species: 4 mg/L Warm water species: 2-3 mg/L Trout Pike Bass, Catfish, Bluegill Stirring and agitation increases oxygen content Cooler Water Still Ponds O2 NO3SO4-2 SO4-2 HS - C6H12O6 + 3SO42- + 3H+ = 6HCO3- + 3HS- Oxygen Oxygen is water soluble, but its solubility is temperature-dependent. In the atmosphere, about one out of 5 molecules is oxygen; in water, about one out of every 100,000 molecules is oxygen. Oxygen enters the water body from the atmosphere and from photosynthesis near the surface Oxygen leaves the water column principally by organism respiration. Oxygen contents of water bodies generally is higher at the surface than at depth. Stirring and agitation increases water’s oxygen content ...
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This note was uploaded on 02/24/2011 for the course SWS 2007 taught by Professor bonczek during the Fall '09 term at University of Florida.

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