Water PollutionWater Pollution

WHAT IS WATER WHAT IS WATER POLLUTIONPOLLUTION Any physical, biological, or chemical Any physical, biological, or chemical

change in water quality that adversely change in water quality that adversely affects living organisms can be affects living organisms can be considered pollution.considered pollution.– Point SourcesPoint Sources - Discharge pollution from - Discharge pollution from

specific locations.specific locations. Factories, Power plantsFactories, Power plants

– Non-Point SourcesNon-Point Sources - Scattered or diffuse, - Scattered or diffuse, having no specific location of discharge.having no specific location of discharge.

Agricultural fields, FeedlotsAgricultural fields, Feedlots

Water PollutionWater Pollution

– Atmospheric DepositionAtmospheric Deposition - - Contaminants carried by air currents Contaminants carried by air currents and precipitated into watersheds or and precipitated into watersheds or directly onto surface waters.directly onto surface waters. Estimated 600,000 kg of the herbicide Estimated 600,000 kg of the herbicide

atrazine in the Great Lakes.atrazine in the Great Lakes.– Most thought to have been deposited Most thought to have been deposited

from the atmosphere.from the atmosphere. Contaminants can also evaporate Contaminants can also evaporate

from lakes.from lakes.

TYPES AND EFFECTS OF WATER POLLUTIONTYPES AND EFFECTS OF WATER POLLUTION

Infectious AgentsInfectious Agents– Main source of waterborne pathogens is Main source of waterborne pathogens is

untreated and improperly treated human untreated and improperly treated human waste.waste. Animal wastes from feedlots and fields is also Animal wastes from feedlots and fields is also

an important source of pathogens.an important source of pathogens.

Infectious AgentsInfectious Agents

In developed countries, sewage treatment In developed countries, sewage treatment plants and pollution-control devices have plants and pollution-control devices have greatly reduced pathogens.greatly reduced pathogens.– Coliform bacteriaColiform bacteria - Intestinal bacteria. - Intestinal bacteria.– ProtistsProtists – drinking water contamination– drinking water contamination– Drinking water generally disinfected via Drinking water generally disinfected via

chlorination.chlorination. At least 2.5 billion people in less developed At least 2.5 billion people in less developed

countries lack adequate sanitation, and about countries lack adequate sanitation, and about half of these lack access to clean drinking half of these lack access to clean drinking water.water.

Thermal PollutionThermal Pollution Industrial cooling processes often Industrial cooling processes often

use heat-exchangers to extract use heat-exchangers to extract excess heat, and then discharge excess heat, and then discharge heated water back into original heated water back into original source.source.– Sources: Coal Burning & Nuclear PlantsSources: Coal Burning & Nuclear Plants

Warm water lowers the ability to hold Warm water lowers the ability to hold oxygen – so…lowers dissolved oxygenoxygen – so…lowers dissolved oxygen

Thermal Shock – rapid temperature change Thermal Shock – rapid temperature change kills fish in the immediate areakills fish in the immediate area

Plant Nutrients and Cultural Plant Nutrients and Cultural EutrophicationEutrophication

OligotrophicOligotrophic - Bodies of water that have - Bodies of water that have clear water and low biological clear water and low biological productivity.productivity.

EutrophicEutrophic - Bodies of water that are rich - Bodies of water that are rich in organisms and organic material.in organisms and organic material.– EutrophicationEutrophication - Process of increasing - Process of increasing

nutrient levels and biological productivity.nutrient levels and biological productivity. Cultural EutrophicationCultural Eutrophication - Increase in - Increase in

biological productivity and ecosystem biological productivity and ecosystem succession caused by human activities.succession caused by human activities.

Organic ChemicalsOrganic Chemicals

Thousands of natural and synthetic organic Thousands of natural and synthetic organic chemicals are used to make chemicals are used to make pesticides, pesticides, plastics, pharmaceuticals, pigmentsplastics, pharmaceuticals, pigments, etc., etc.

Two most important sources of toxic Two most important sources of toxic organic chemicals in water are:organic chemicals in water are:– Improper disposal of Improper disposal of industrialindustrial and and householdhousehold

wastes.wastes.– Runoff of pesticides from high-use areas & Runoff of pesticides from high-use areas &

farms.farms. Fields, roadsides, golf coursesFields, roadsides, golf courses

Oxygen-Demanding Oxygen-Demanding WastesWastes Water with a dissolved oxygen content Water with a dissolved oxygen content > 6 ppm will support desirable aquatic life.> 6 ppm will support desirable aquatic life.

– Water with < 2 ppm DO will support mainly Water with < 2 ppm DO will support mainly detritivores and decomposers.detritivores and decomposers.

Oxygen is added to water by diffusion Oxygen is added to water by diffusion from wind and waves, and by from wind and waves, and by photosynthesis from photosynthesis from green plants, green plants, algae, and cyanobacteriaalgae, and cyanobacteria..– Oxygen is removed from water by respiration Oxygen is removed from water by respiration

and oxygen-consuming processes.and oxygen-consuming processes.

Oxygen-Demanding Oxygen-Demanding WastesWastes Biochemical Oxygen DemandBiochemical Oxygen Demand - Amount - Amount

of dissolved oxygen consumed by of dissolved oxygen consumed by aquatic microorganisms.aquatic microorganisms.– Dissolved Oxygen ContentDissolved Oxygen Content - Measure of - Measure of

dissolved oxygen in the water.dissolved oxygen in the water. Effects of oxygen-demanding wastes Effects of oxygen-demanding wastes

on rivers depend on volume, flow, and on rivers depend on volume, flow, and temperature of river water.temperature of river water.– Oxygen SagOxygen Sag - Oxygen levels decline - Oxygen levels decline

downstream from a pollution source as downstream from a pollution source as decomposers metabolize waste materials.decomposers metabolize waste materials.

INPUT of WASTE or THERMAL POLLINPUT of WASTE or THERMAL POLLUUTIONTION

SedimentSediment Human activities have Human activities have

accelerated erosion rates in accelerated erosion rates in many areas.many areas.– Human-induced erosion and Human-induced erosion and

runoff contribute about 75 billion runoff contribute about 75 billion metric tons of suspended solids metric tons of suspended solids to world surfaces each year.to world surfaces each year.

Sediment can either be Sediment can either be beneficial (nourish floodplains) beneficial (nourish floodplains) or harmful (smother aquatic or harmful (smother aquatic life – decrease life – decrease photosynthesis).photosynthesis).

Inorganic PollutantsInorganic Pollutants

Metals Metals – Many metals such as Many metals such as mercurymercury, lead, , lead,

cadmium, and nickel are highly toxic.cadmium, and nickel are highly toxic. Highly persistent and tend to Highly persistent and tend to

bioaccumulate in food chains.bioaccumulate in food chains.– Lead pipes are a serious source of Lead pipes are a serious source of

drinking water pollution.drinking water pollution.– Mine drainage and leaching are Mine drainage and leaching are

serious sources of environmental serious sources of environmental contamination. contamination.

Inorganic PollutantsInorganic Pollutants

Nonmetallic SaltsNonmetallic Salts– Many salts that are non-toxic at low Many salts that are non-toxic at low

concentrations can be mobilized by concentrations can be mobilized by irrigation and concentrated by evaporation, irrigation and concentrated by evaporation, reaching levels toxic to plants and animals.reaching levels toxic to plants and animals.

Leaching of road salts has had detrimental effect Leaching of road salts has had detrimental effect on many ecosystems.on many ecosystems.

Acids and BasesAcids and Bases– Often released as by-products of industrial Often released as by-products of industrial

processes.processes.

WATER QUALITY WATER QUALITY TODAYTODAY Areas of ProgressAreas of Progress

– Clean Water ActClean Water Act (1972) established a (1972) established a National Pollution Discharge System National Pollution Discharge System which requires a permit for any entity which requires a permit for any entity dumping wastes in surface waters.dumping wastes in surface waters. In 1999, EPA reported 91.4% of all In 1999, EPA reported 91.4% of all

monitored river miles and 87.5% of all monitored river miles and 87.5% of all accessed lake acres are suitable for their accessed lake acres are suitable for their designated uses.designated uses.

– Most progress due to municipal sewage Most progress due to municipal sewage treatment facilities.treatment facilities.

Water Quality TodayWater Quality Today

Remaining ProblemsRemaining Problems Greatest impediments to achieving Greatest impediments to achieving

national goals in water quality are national goals in water quality are sedimentsediment, , nutrientsnutrients, and , and pathogenspathogens, especially from non-point , especially from non-point discharges.discharges.– About three-quarters of water pollution in About three-quarters of water pollution in

the US comes from soil erosion, air the US comes from soil erosion, air pollution fallout, and agricultural and urban pollution fallout, and agricultural and urban runoff.runoff. Single cow produces 30 kg manure/day.Single cow produces 30 kg manure/day.

– Some feedlots have 100,000 animals.Some feedlots have 100,000 animals.

Open Pit Mines (coal, copper, Open Pit Mines (coal, copper, uranium, lead, gold, silver)uranium, lead, gold, silver)

Exposes waste rock like pyrite Exposes waste rock like pyrite (FeS(FeS22) which can react with ) which can react with water to form sulfuric acid.water to form sulfuric acid.

Releases ferric ions (Fe++)Releases ferric ions (Fe++) Leaches toxic heavy metals Leaches toxic heavy metals

(Al3+, Zn2+)(Al3+, Zn2+) Red Staining “Yellow Boy”Red Staining “Yellow Boy” Changes pH (can be higher or Changes pH (can be higher or

lower as it degrades natural lower as it degrades natural buffersbuffers

Increases conductivity and Increases conductivity and hardnesshardness

Groundwater and Drinking Groundwater and Drinking WaterWater

About half the US population, and 95% About half the US population, and 95% of rural residents, depend on of rural residents, depend on underground aquifers for drinking underground aquifers for drinking water.water.– For decades, groundwater was assumed For decades, groundwater was assumed

impervious to pollution and was impervious to pollution and was considered the gold standard for water considered the gold standard for water quality.quality. Estimated 1.5 million Americans fall ill Estimated 1.5 million Americans fall ill

from fecal contamination annually.from fecal contamination annually.– Cryptosporidium outbreaksCryptosporidium outbreaks

Groundwater and Drinking Groundwater and Drinking WaterWater

Leaks from storage Leaks from storage lagoons, septic tanks, & lagoons, septic tanks, & landfillslandfills

Agricultural runoff - Agricultural runoff - pesticidespesticides

Other Organic toxins – Other Organic toxins – solvents, paints, oil, MTBEsolvents, paints, oil, MTBE

(human health risk arise (human health risk arise from petrochemicals, from petrochemicals, organic solvents, organic solvents, pesticide, arsenic, pesticide, arsenic, fluorine, & lead)fluorine, & lead)

EPA estimates 4.5 EPA estimates 4.5 trillion liters of trillion liters of contaminated contaminated water seep into water seep into the ground in the the ground in the US every day.US every day.

51% of Drinking 51% of Drinking Water comes from Water comes from Ground WaterGround Water

Groundwater PollutionGroundwater Pollution

Surface Waters in Other Surface Waters in Other CountriesCountries

Sewage treatment in wealthier countries Sewage treatment in wealthier countries of of EuropeEurope generally equal or surpass the generally equal or surpass the US.US.

In In RussiaRussia, only about half of the tap water , only about half of the tap water supply is safe to drink.supply is safe to drink.

In urban areas of In urban areas of South America, Africa, South America, Africa, and Asiaand Asia, 95% of all sewage is discharged , 95% of all sewage is discharged untreated into rivers.untreated into rivers.

Two-thirds of Two-thirds of India’sIndia’s surface waters are surface waters are contaminated sufficiently to be considered contaminated sufficiently to be considered dangerous to human health.dangerous to human health.

Contain 95% of Contain 95% of freshwater (surface) in freshwater (surface) in US; 20% globallyUS; 20% globally

14% of US population 14% of US population lives in lake basin; 30% lives in lake basin; 30% CanadaCanada

Heavily Polluted – suffers Heavily Polluted – suffers from mercury, PCB’s, from mercury, PCB’s, cultural eutrophication, cultural eutrophication, & bacterial contaminents& bacterial contaminents

2/3 of basin wetlands 2/3 of basin wetlands have been lost in the last have been lost in the last 400 yrs. 400 yrs.

Belugas’ body mass is so polluted if they wash ashore they have to be disposed of as “toxic waste”Through improved sewage treatment, Through improved sewage treatment,

treatment of industrial waste, & ban treatment of industrial waste, & ban on phosphates have improved water on phosphates have improved water quality drasticallyquality drastically