urban water quality
DESCRIPTION
Urban Water Quality. Water Quality. Pollution - any departure from “purity” What is “purity”? Characteristics of water Is drinking water “pure”?. Water Quality. - PowerPoint PPT PresentationTRANSCRIPT
Urban Water Quality Urban Water Quality
Water QualityWater Quality
PollutionPollution - any departure from - any departure from “purity” “purity”
– What is “purity”?What is “purity”?– Characteristics of waterCharacteristics of water– Is drinking water “pure”?Is drinking water “pure”?
Water QualityWater Quality
Pure WaterPure Water - - in the context of in the context of water pollution, a state of water pollution, a state of water in which no substance is water in which no substance is present in sufficient present in sufficient concentration to prevent the concentration to prevent the water from being used for the water from being used for the purposes thought of as purposes thought of as “normal”“normal”
Water QualityWater Quality
““Normal” uses of water?Normal” uses of water?– RecreationRecreation– Public water supplyPublic water supply– Aquatic habitatsAquatic habitats– AgricultureAgriculture– IndustryIndustry
Water QualityWater Quality
Water PollutantWater Pollutant - - any any substance that prevents the substance that prevents the “normal” use of water“normal” use of water
– ““Normal” implies a value Normal” implies a value judgement and depends on the judgement and depends on the particular useparticular use
Water QualityWater Quality
Water Quality - Water Quality - the physical the physical and chemical characteristics of and chemical characteristics of waterwater
– Unrelated to the particular use in Unrelated to the particular use in that no value judgement is that no value judgement is assignedassigned
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
Signs of water pollution?Signs of water pollution?– Bad tasting drinking waterBad tasting drinking water– Masses of aquatic weedsMasses of aquatic weeds– Disgusting odorsDisgusting odors– Decreasing fish populationsDecreasing fish populations– Floating oil and raw sewageFloating oil and raw sewage
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
Classification of water pollutantsClassification of water pollutants– Oxygen-demanding wastes (ODW)Oxygen-demanding wastes (ODW)– Pathogenic organismsPathogenic organisms– Plant nutrientsPlant nutrients– Synthetic organic compounds (SOCs)Synthetic organic compounds (SOCs)– OilOil– SedimentsSediments– HeatHeat
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
Oxygen-Demanding Wastes Oxygen-Demanding Wastes (ODW)(ODW)– Dissolved OxygenDissolved Oxygen
Aquatic organisms require oxygen Aquatic organisms require oxygen for for cellular respirationcellular respiration
Dissolved oxygen (DO) is often a Dissolved oxygen (DO) is often a limiting factor for survival of aquatic limiting factor for survival of aquatic organismsorganisms
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Dissolved OxygenDissolved Oxygen
Factors that control DO levels:Factors that control DO levels:– Water temperatureWater temperature– Elevation above sea levelElevation above sea level– Degree of turbulence Degree of turbulence – Stream channel geometryStream channel geometry– Density of aquatic plantsDensity of aquatic plants
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Dissolved OxygenDissolved Oxygen
Water TemperatureWater Temperature– DO decreases with increasing water DO decreases with increasing water
temperaturetemperature
Elevation Above Sea LevelElevation Above Sea Level– DO decreases with increasing elevationDO decreases with increasing elevation
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Dissolved OxygenDissolved Oxygen
TurbulenceTurbulence– DO increases with increasing turbulence DO increases with increasing turbulence
caused by waterfalls, rapids, etccaused by waterfalls, rapids, etc
Stream Channel GeometryStream Channel Geometry– Wide,shallow channel has greater DO Wide,shallow channel has greater DO
than narrow, deep channelthan narrow, deep channel
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Organic substances that cause Organic substances that cause
depletion or removal of DOdepletion or removal of DO– Food source for aquatic bacteriaFood source for aquatic bacteria– DO is removed as bacteria feed DO is removed as bacteria feed
on ODWon ODW
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Sources of ODWSources of ODW
SewageSewage Paper millsPaper mills Food processingFood processing SlaughterhousesSlaughterhouses
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Biochemical Oxygen DemandBiochemical Oxygen Demand - -
the amount of dissolved oxygen the amount of dissolved oxygen that bacteria require to that bacteria require to decompose ODW in a given decompose ODW in a given volume of watervolume of water
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Biochemical Oxygen Demand Biochemical Oxygen Demand
(BOD)(BOD) MeasurementMeasurement
– 5-day test5-day test– Incubation at 20 degrees CIncubation at 20 degrees C– BOD = DO (day 0) - DO (day 5)BOD = DO (day 0) - DO (day 5)
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODWODW– Biochemical Oxygen Demand Biochemical Oxygen Demand
(BOD)(BOD) Characteristic BOD LevelsCharacteristic BOD Levels
– Untreated SewageUntreated Sewage 100-400 mg/L100-400 mg/L– FeedlotsFeedlots 100-10,000 100-10,000
mg/Lmg/L– Pure WaterPure Water 1 mg/L1 mg/L
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
ODW ODW – Environmental Impacts of low DOEnvironmental Impacts of low DO
Disappearance of plant and animal lifeDisappearance of plant and animal life Shift from aerobic to anaerobic conditionsShift from aerobic to anaerobic conditions “ “Oxygen Sag”Oxygen Sag”
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
Pathogenic Organisms Pathogenic Organisms – Types of pathogens:Types of pathogens:
VirusesViruses BacteriaBacteria Protozoa (unicellular)Protozoa (unicellular) Parasitic wormsParasitic worms
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants
Pathogenic Organisms Pathogenic Organisms – Diseases caused by water-borne Diseases caused by water-borne
pathogens:pathogens: Amoebic DysenteryAmoebic Dysentery Bacterial DysenteryBacterial Dysentery Typhoid feverTyphoid fever CholeraCholera HepatitisHepatitis SchistosomiasisSchistosomiasis
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Pathogenic Organisms Pathogenic Organisms
– Sources of body wastes:Sources of body wastes: Malfunctioning septic tanks, cesspoolsMalfunctioning septic tanks, cesspools Untreated sewageUntreated sewage Waste discharges from boats and shipsWaste discharges from boats and ships Meat processing plantsMeat processing plants Swimmers and hikersSwimmers and hikers
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Pathogenic Organisms Pathogenic Organisms
– Testing for pathogenic organismsTesting for pathogenic organisms Coliform Coliform bacteriabacteria
– Live in large intestines of warm-blooded Live in large intestines of warm-blooded animals (even Uncle Monty) and absorb animals (even Uncle Monty) and absorb nutrients from their surroundingsnutrients from their surroundings
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Plants require 15-20 nutrients for Plants require 15-20 nutrients for growth:growth:
CarbonCarbon NitrogenNitrogen PhosphorusPhosphorus PotassiumPotassium SulfurSulfur
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Nitrogen and phosphorus are Nitrogen and phosphorus are limiting nutrients for plant growthlimiting nutrients for plant growth
– EutrophicationEutrophication - - the natural the natural enrichment of water with plant enrichment of water with plant nutrientsnutrients
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Eutrophic EcosystemEutrophic Ecosystem - - ecosystems that ecosystems that are relatively high in fertility and are relatively high in fertility and biological productivitybiological productivity
– Oligotrophic EcosystemOligotrophic Ecosystem - - ecosystems ecosystems that are relatively low in fertility and that are relatively low in fertility and biological productivitybiological productivity
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Cultural EutrophicationCultural Eutrophication - - accelerated accelerated eutrophication caused by human eutrophication caused by human activitiesactivities
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Signs and effects of cultural Signs and effects of cultural eutrophication:eutrophication:
Dense growth of rooted plantsDense growth of rooted plants Increased growth of blue-green algaeIncreased growth of blue-green algae Increased populations of trash fishIncreased populations of trash fish Foamy layers on surface of waterFoamy layers on surface of water
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Sources of nutrients responsible for Sources of nutrients responsible for cultural cultural eutrophication:cultural cultural eutrophication:
Domestic SewageDomestic Sewage Urban RunoffUrban Runoff Industrial SourcesIndustrial Sources Agricultural SourcesAgricultural Sources
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Management practices to minimize Management practices to minimize cultural eutrophication:cultural eutrophication:
Two types of water pollution sources in a Two types of water pollution sources in a watershed:watershed:
– Point SourcePoint Source– Non-Point Source PollutionNon-Point Source Pollution
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Plant Nutrients Plant Nutrients
– Management practices to minimize Management practices to minimize cultural eutrophication:cultural eutrophication:
Nutrient managementNutrient management– Determine point and nonpoint sources of Determine point and nonpoint sources of
nutrients and the size of each sourcenutrients and the size of each source– On-site treatment of nutrientsOn-site treatment of nutrients– Rate and timing of nutrient applicationRate and timing of nutrient application
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Synthetic Organic Compounds Synthetic Organic Compounds
(SOCs) (SOCs) – Examples:Examples:
FuelsFuels PlasticsPlastics PesticidesPesticides FertilizersFertilizers Food additivesFood additives PharmaceuticalsPharmaceuticals
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Synthetic Organic Compounds Synthetic Organic Compounds
(SOCs) (SOCs) – PesticidesPesticides
Environmental ImpactsEnvironmental Impacts– BioaccumulationBioaccumulation– Interference with reproductionInterference with reproduction– Birth DefectsBirth Defects– Reduced biodiversity and productivityReduced biodiversity and productivity– Tumors and convulsions Tumors and convulsions
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Synthetic Organic Compounds Synthetic Organic Compounds
(SOCs) (SOCs) – Oil (Hydrocarbons)Oil (Hydrocarbons)
SourcesSources– Impervious surfacesImpervious surfaces– Oil leaksOil leaks– Auto emissionsAuto emissions– Improper disposal of waste oilImproper disposal of waste oil
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Synthetic Organic Compounds Synthetic Organic Compounds
(SOCs) (SOCs) – Oil (Hydrocarbons)Oil (Hydrocarbons)
Environmental ImpactsEnvironmental Impacts– Degrade appearance of water surfacesDegrade appearance of water surfaces– Limit air exchange between atmosphere and Limit air exchange between atmosphere and
waterwater– Lowered DO levelsLowered DO levels– Increased BODIncreased BOD– Impair habitatImpair habitat– Reduced biodiversityReduced biodiversity– DeathDeath
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Sediment Sediment
– Most common of the nonpoint source Most common of the nonpoint source pollutantspollutants
– Sediment load in waterways Sediment load in waterways increases with increasing increases with increasing urbanization and landuse intensityurbanization and landuse intensity
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Sediment Sediment
– Factors controlling sediment loss:Factors controlling sediment loss: Chemical and physical characteristics of Chemical and physical characteristics of
the soilthe soil Slope steepnessSlope steepness Type and density of vegetation coverType and density of vegetation cover RainfallRainfall
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants SedimentSediment
– Environmental Impacts Environmental Impacts Filling of channels and harbors with Filling of channels and harbors with
sedimentsediment Decreased biodiversity of aquatic Decreased biodiversity of aquatic
animalsanimals Increased turbidityIncreased turbidity
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Heat (Thermal Pollution)Heat (Thermal Pollution)
– SourcesSources Cooling water in industrial processesCooling water in industrial processes Natural heating by sunlightNatural heating by sunlight
– Environmental ImpactsEnvironmental Impacts Decreased DODecreased DO Increased rates of chemical reactionsIncreased rates of chemical reactions False temperature cues to aquatic lifeFalse temperature cues to aquatic life Death to aquatic organismsDeath to aquatic organisms
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Heat (Thermal Pollution)Heat (Thermal Pollution)
– Environmental ImpactsEnvironmental Impacts Decreased DODecreased DO
– ““Thermal Blanket”Thermal Blanket” Warm water is less dense than cold waterWarm water is less dense than cold water Warm layer forms “blanket” over cooler, more Warm layer forms “blanket” over cooler, more
dense waterdense water Warm water cannot dissolve as much Warm water cannot dissolve as much
atmospheric oxygen as cooler wateratmospheric oxygen as cooler water Rate of exchange of oxygen between warm Rate of exchange of oxygen between warm
water and cooler water is very slowwater and cooler water is very slow Cooler water is “atmospherically Cooler water is “atmospherically
unreplenished”unreplenished” Death to aquatic organismsDeath to aquatic organisms
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Heat (Thermal Pollution)Heat (Thermal Pollution)
– Environmental ImpactsEnvironmental Impacts Increased rates of chemical reactionsIncreased rates of chemical reactions
– The rate of any chemical reactions The rate of any chemical reactions approximately doubles with every 10C approximately doubles with every 10C increase in temperatureincrease in temperature
– In thermally polluted waters, fish require In thermally polluted waters, fish require more DO because of increased respiration more DO because of increased respiration rates rates
– Increased respiration occurs in response to Increased respiration occurs in response to higher water temperaturehigher water temperature
Water Quality - Water Quality - Classification of Water Classification of Water
PollutantsPollutants Heat (Thermal Pollution)Heat (Thermal Pollution)
– Environmental ImpactsEnvironmental Impacts False temperature cues given to aquatic False temperature cues given to aquatic
lifelife– Fish spawn and migrate in response to Fish spawn and migrate in response to
temperature cuestemperature cues– Optimum temperature range for fish speciesOptimum temperature range for fish species