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25 Biological Pollution Pathogens

25 Biological Pollution Pathogens - Cities Rivers Wastes...

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Unformatted text preview: Cities, Rivers, Wastes and Biological Pollution Rivers and Cities London Thames Rome Venice Tiber Seine Paris Hudson NYC Rivers and Cities Dependable Water Supply Removal of Wastes History of Water Supply and Biological Pollution Sumer 2500 B.C. Irrigation Aqueducts Sewers Water Supply and Sewer Systems Aqueduct sewers waterways Roman Aqueducts 255 miles of aqueducts Stone, lined with cement Water distributed through lead pipes and logs 144 public latrines 1 million people Lead (Plumbum) Father of all metals Saturn: the deity of lead -lead pipes -lead acetate sugar of lead sweetener for wine Saturnine: an individual whose temperament has become uniformly gloomy and cynical. Possible cause of the dementia which affected Roman Emperors and Citizens. Possible contributing factor to the Fall of the Roman empire Caligula, Nero, Commodus, Julius Caesar, Caesar Augustus Domitian’s Fountain of leaded wine After the Fall 500 to 1500 A.D. Neglect of infrastructure City wells fouled Diverted Wealth drinking water hauled in from springs outside the city limits reduced the population of the city of Rome from its high of over 1 million in ancient times to considerably less in the medieval era, reaching as low as 30,000 17th to 19th Centuries Growth of Urban Populations Deterioration of wells Cesspools/outhouses Leaching Offensive Odor And taste. 270,000 cubic meters of manure (Paris, 1780) Graveyards in City Limits New York’s Trinity Church held 160,000 graves by 1830. “rank and offensive mold, mixed with broken bones and fragments of coffins” Basil Hall, 1820 Cesspits “Nearly every residence had a cesspit beneath the floors. In the best of homes the nauseating stench permeated the most elegant parlor.” To river or street When cesspits filled to overflow, they were built to drain to the street by means of a crudely built culvert to a partially open sewer trench in the center of the street London's sewers were open ditches sloped slightly to drain human wastes toward the River Thames Cesspits and Night Soil c.a. 1850 Cesspits Night Soil Methane (CH ) 4 Methanogenesis is the final step in the decay of organic matter under anoxic conditions Anaerobic organisms: Exist in low oxygen CH + 2O lamps O + 2H O =C 4 2 2 2 Southampton, 1849: "Explosions occurred in two separate locations where the men had the skin peeled off their faces and their hair singed”. 19th Century The Age of the Toilet John Harrington 1596 Alexander Cummings 1775 Not widely adopted until the mid to late 1800s Thomas Crapper 1866 Effectively marketed the toilet By 1885, Boston had 100,000 toilets and thousands of miles of pipe carrying wastewater to rivers. Toilets, Cesspools, Wastes and Urbanization Wastewater to Rivers 1 1861 Suspension of British Parliament Typhoid Epidemic Connected with contaminated water Thames River: mid-1800s Extra Credit: 1. The inventor of the toilet ___________________________ 1. Built over 255 miles of aqueducts ____________________ 1. The first sewer and water systems were built when? 1. Metal that may have contributed to dementia of Romans. Disease The World Health Organization indicates that every year more than 3.4 million people die as a result of water related diseases, making it the leading cause of disease and death around the world. Most of the victims are young children, the vast majority of whom die of illnesses caused by organisms that thrive in water sources contaminated by raw sewage. Diseases Cholera Botulism Typhoid Hepatitis A Dysentery Responsible pathogen Vibrio cholerae bacteria Clostridium botulinum bacteria Salmonella typhi bacteria Hepatitis A virus Shigella dysenteriae bacteria or Entamoeba histolytica amoeba Cryptosporidium parvum protozoa polioviruses Route of exposure gastro­ intestinal gastro­ intestinal gastro­ intestinal gastro­ intestinal gastro­ intestinal Mode of transmission sewage, often waterborne food/water borne; can grow in food water/food borne water/food borne food/water Cryptosporidiosis Polio gastro­ intestinal gastro­ intestinal gastro­ intestinal waterborne; resists chlorine exposure to untreated sewage; may also be waterborne waterborne Giardia Giardia lamblia protozoa Typhoid 1837, 1860-1865 186,000 people Typhoid fever is an illness caused by the bacterium Salmonella Typhi and is transmitted by ingestion of food or water contaminated with feces from an infected person The worst year was 1891, when the typhoid death rate was 174 per 100,000 persons Cholera Vibrio cholerae Intestinal disease Occurs through ingesting food or water which is contaminated with cholera vibrios In its most severe forms, cholera is one of the most rapidly fatal illnesses known Shock from dehydration can occur in 4 to 12 hours death within 18 hours to several days 8 major outbreaks from 1816 to 1896 affecting mostly Europe and N. America 1852-1860 - Third cholera pandemic mainly affected Russia, with over a million deaths Cholera in the U.S. Epidemic of 1832 killed over 6,500 people in London and 3500 in NY Croton Aqueduct System 50 miles of aqueduct Treatment: Rehydration Therapy Intravenous Fluid Therapy 1831 mortality rate of cholera dropped from 70% to 40% Oral Rehydration Therapy (1960s) The Indo-Pakistani War of 1971 – mortality rate of 3% ORT solution contains: sodium chloride (NaCl) trisodium citrate dehydrate potassium chloride (KCl) glucose Gatorade Sodium chloride (NaCl) Citric acid Potassium phosphate glucose Currently, WHO recommends a 3-day, 12-dose course of antibiotic treatment with either tetracycline or erythromycin Cause of Disease "Cholera was a scourge not of mankind but of the sinner." Bernhard J. Stern, Society and Medical Progress (1941) 50% mortality rate among its healthy adult victims Miasma and Night Air Theory of used to explain the spread of disease in London and Paris A poisonous vapor or mist that is filled with particles from decomposed matter (miasmata) that could cause illnesses and is identifiable by its nasty, foul smell Doors and windows of homes and factories were sealed shut at sunset. The Microscopic Revolution The Microscope Anton van Leeuwenhoek: first microbiologist 1880: Pasteur published book on germ theory “people had a dreadful apprehension of breeding bullfrogs inwardly.” Revolutionized knowledge of the causes of disease 1880 - 1885 Organisms Discovered Malaria typhoid tuberculosis diphtheria cholera tetanus Discovery of coliform bacteria Greatest impact on municipal water systems and water treatment. Theodor Escherich 1886 Most forms of e. coli are harmless E. coli 1/3 weight of average uninfected human waste Biological pollution Total Coliforms (including fecal coliform and E. Coli) Not necessarily a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present Coliforms are naturally present in the environment; fecal coliforms only come from human and animal fecal waste. Standards based on presence or absence Freshwater Standard: ~200 units/100 mL Drinking Water MCL = no more than 5.0% total samples coliform-positive in a month Initiation of Water Treatment Biological Pollutants and Water Quality Initial Forms of Water Treatment Removal of Suspended Solids Flocculation Sand filtration Flocculation – bringing together of high numbers of small particles to create larger particles which settle out of water quickly. First water treatment: Flocculation 2000 B.C. Turbidity Suspended Organic and inorganic particles Suspended particles often function as a habitat for microorganisms Higher turbidity levels are often associated with higher levels of viruses, parasites and bacteria. Turbidity is caused by the suspension of very small particles in water. Settling Velocity proportional to diameter squared Small particles settle slowly Large particles settle quickly Many of the particles that cause turbidity carry a negative electrical charge. Flocculation Small organic and Inorganic particles - charge Al3+ Al3+ Al3+ - charge - charge Settling rate of particles is proportional to the square of the diameter Small particles settle slowly, large particle settle quickly from water Flocculation Al3+ Clear Water Small, Suspended Particles Flocculated particles Contaminants, pathogens Filtration Water particles solids Clearer Water Slow 0.4 m/hour Physical/ biological straining Particles smaller than the spaces between sand grains are trapped Antagonistic bacteria destroy Pathogenic bacteria Fast 21 m/hour Physical straining Particles larger than the pore spaces between the sand grains are trapped Chlorination Chlorination • gaseous chlorine • sodium hypochlorite • calcium hypochlorite Common chemical bleaches include household "chlorine bleach", a solution of approximately 3-6% sodium hypochlorite (NaClO) A 12% solution is widely used in waterworks for the chlorination of water and a 15% solution is more commonly used for disinfection of waste water in treatment plants. High-test hypochlorite (HTH) is sold for chlorination of swimming pools and contains approximately 30% calcium hypochlorite. Chlorine Disinfection NaOCl = Na + + OCl - hypochlorous acid (HOCl) and hypochlorite ion (OCl-). Low pH High pH hypochlorous acid (HOCl) is responsible for the disinfecting power. Low pH favors high levels of HOCl over OCl- Destroys cell enzymes Penetrates bacterial cell Bacterial death is rapid Cholera and Chlorine The first known uses of chlorine for water disinfection was by John Snow in 1854, when he attempted to disinfect the Broad Street Pump water supply The intersection of Cambridge and Broad Street, up to 500 deaths from Cholera occurred within 10 days public well had been dug only three feet from an old cesspit Applied to municipal water systems in 1909 Chlorination Chlorine is currently employed by over 98 percent of all U.S. water utilities that disinfect drinking water Effectiveness of Chlorination: Typhoid Yardstick 174 per 100,000 persons died of Typhoid in 1891 Deaths per 100,000 bacterium Salmonella typhi 1860 1910 1935 Today: < 40 per 200 million people ...
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