Lecture-2 Lecture-2 Water PollutionWater Pollution

Centre for Environmental Science and Engineering

IIT Bombay

Sources of Water PollutionSources of Water Pollution

Water PollutionWater Pollution

DefinitionDefinition = physical, chemical, biological changes in physical, chemical, biological changes in water quality that adversely affect living organisms. (i.e., water quality that adversely affect living organisms. (i.e., degradation)degradation)

Types:Types:Infectious Agents - microorganismsInfectious Agents - microorganismsOxygen-Demanding Wastes – organic matterOxygen-Demanding Wastes – organic matterInorganic Pollutants – mostly metalsInorganic Pollutants – mostly metalsOrganic ChemicalsOrganic ChemicalsSediment (Particulates) Sediment (Particulates) Thermal Pollution – high temp-low D.O.Thermal Pollution – high temp-low D.O.

Infectious Agents- Source-warm Infectious Agents- Source-warm blooded animalsblooded animals

Infectious AgentsInfectious Agents = pathogenic organisms. Water-borne = pathogenic organisms. Water-borne diseases from infectious agents include typhoid, diseases from infectious agents include typhoid, cholera, bacterial and amoebic dysentery, polio, cholera, bacterial and amoebic dysentery, polio, infectious hepatitis, guinea worm and schistosomiasis. infectious hepatitis, guinea worm and schistosomiasis. Due to lack Due to lack of sanitationof sanitation. .

Analyze coliform bacteria Analyze coliform bacteria ((E. coliE. coli). Presume if ). Presume if coliform bacteria are present, infectious pathogens are coliform bacteria are present, infectious pathogens are also present. also present. MPN testMPN test

EutrophicationEutrophicationEutrophication is the natural process by which waters (lakes, rivers etc) become excessively enriched with nutrients, typically nitrogen and phosphorus. It is one of the ways in which a water body (lake, rivers, and seas) transforms from a state where nutrients are scarce (oligotrophic), through a slightly richer phase (mesotrophic) to an enriched state (eutrophic).

Human activities often enhance the rate of change due to activities such as farming, forestry, road-building, industry and waste treatment that cause nutrients to enter watercourses. This nutrient enrichment often results in a population explosion of algae and other aquatic plants.

Oxygen-Demanding WastesOxygen-Demanding Wastes

Oxygen dissolved in water is indicator of water quality. 6 Oxygen dissolved in water is indicator of water quality. 6 ppm Oppm O22 or more supports desirable aquatic life. or more supports desirable aquatic life.

BOD BOD (biochemical oxygen demand) measures the amount of (biochemical oxygen demand) measures the amount of dissolved oxygen consumed by aquatic microorganisms. dissolved oxygen consumed by aquatic microorganisms. Sewage, paper pulp, or food wastes can cause an Sewage, paper pulp, or food wastes can cause an Oxygen Oxygen sag, sag, where few fish survive.where few fish survive.

EutrophicationEutrophicationBOD and EutrophicationBOD and Eutrophication - rapid succession in a body of - rapid succession in a body of water because of an increase in biological productivity. water because of an increase in biological productivity. ((OligotrophicOligotrophic lakes and rivers have clear water and low lakes and rivers have clear water and low biological productivity).biological productivity).

Eutrophication - SolutionsEutrophication - Solutions

Wastewater treatment-?Wastewater treatment-?

Limit your fertilizer use and apply at appropriate timesLimit your fertilizer use and apply at appropriate times

Control runoff and soil erosionControl runoff and soil erosion

Start a compost pile and recycle yard wasteStart a compost pile and recycle yard waste

Conserve water and energyConserve water and energy

Plant trees and other deep root plantsPlant trees and other deep root plants

Inorganic PollutantsInorganic Pollutants

Heavy metals, like mercury, lead, tin, cadmium, selenium, Heavy metals, like mercury, lead, tin, cadmium, selenium, and arsenic are caused by human activities.and arsenic are caused by human activities.

Inorganic PollutantsInorganic PollutantsToxic MetalsToxic Metals: Effect at the DNA level- genetic changes: Effect at the DNA level- genetic changes

Mercury poisoningMercury poisoning from coal, incineration from coal, incineration Causes:Causes: - damage to the nervous - damage to the nervous

system system metal retardationmetal retardationcerebral palsycerebral palsydevelopment delaysdevelopment delays

- kidney disorders- kidney disorders

Lead poisoning Lead poisoning from incineration, pipes, solder from incineration, pipes, solder (previously in shot, gasoline)(previously in shot, gasoline)

Causes: Causes: - miscarriages- miscarriages- hearing loss- hearing loss- learning disabilities- learning disabilities

Inorganic PollutantsInorganic PollutantsNonmetallic Salts:

ArsenicArsenic from mining or drainage of desert soils from mining or drainage of desert soils Causes: Causes: - anemia- anemia

- cancer- cancer- death.- death.

Sodium Chloride:Sodium Chloride: Salinization Salinization

Acids:Acids: Sulfur and nitrogen compoundsSulfur and nitrogen compounds from coal. from coal.

Causes: Causes: - pH changes which affect species- pH changes which affect species- leaches aluminum- leaches aluminum

POPsPOPs

Persistent Organic Pollutants (POPs) are Persistent Organic Pollutants (POPs) are chemical substances that persist in the environment, bioaccumulate through the food web, and pose a risk of causing adverse effects to human health and the environment.

The "dirty dozen" includes: PCBs, aldrin, chlordane, DDT, The "dirty dozen" includes: PCBs, aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorbenzene, mirex, dieldrin, endrin, heptachlor, hexachlorbenzene, mirex, polychlorinated dibenzo-p-dioxins, polychlorinated polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and toxaphene.dibenzofurans, and toxaphene.

Organic PollutantsOrganic Pollutants

Examples = Dioxin, PCB, DDT Examples = Dioxin, PCB, DDT (Chlorinated)(Chlorinated)

DioxinDioxin: stable; slow to degrade: stable; slow to degrade

Organic Pollutants - DioxinOrganic Pollutants - Dioxin

Generated from:Generated from: Burning wood, coal, oil, household Burning wood, coal, oil, household trash, and chlorine bleaching of pulp and papertrash, and chlorine bleaching of pulp and paper

Accumulates in fat of animalsAccumulates in fat of animals biomagnificationbiomagnification

Causes:Causes: cancercancerweakened immune responseweakened immune response

Organic Pollutants - PCBsOrganic Pollutants - PCBs

PCB = PCB = non-flammable; not dissolved in water; high non-flammable; not dissolved in water; high boiling points; does not conduct electricity well. So used boiling points; does not conduct electricity well. So used for for transformers and capacitorstransformers and capacitors..

Organic Pollutants - PCBsOrganic Pollutants - PCBs

More than one More than one billion poundsbillion pounds of PCBs have been made. of PCBs have been made.

Accumulates in fat of animalsAccumulates in fat of animals biomagnificationbiomagnification

Causes:Causes: cancer cancer hormonal and reproductive disruptionshormonal and reproductive disruptionsdecrease cognitive abilities (dopamine)decrease cognitive abilities (dopamine)

Organic Pollutants - DDTOrganic Pollutants - DDT

DDT is an insecticide; stable and slow to degrade.DDT is an insecticide; stable and slow to degrade.

Paul MullerPaul Muller won the Nobel Prize in 1948 for developing won the Nobel Prize in 1948 for developing DDT.DDT.

Benefits = Benefits = Controlled spread of malaria; Provided crop Controlled spread of malaria; Provided crop protectionprotection

Organic Pollutants - DDTOrganic Pollutants - DDT

Organic Pollutants - DDTOrganic Pollutants - DDTProblems with DDT: DDT is not metabolized very rapidly Problems with DDT: DDT is not metabolized very rapidly by animals; instead, it is deposited and stored in the fatty by animals; instead, it is deposited and stored in the fatty tissues tissues biomagnification biomagnification

Organic Pollutants - DDTOrganic Pollutants - DDT Toxic to fish Toxic to fish

Increased mortality in birds: calcium decreased in egg shellsIncreased mortality in birds: calcium decreased in egg shells

Organic Pollutants - DDTOrganic Pollutants - DDT Estrogen mimic in Vertebrates: feminizes males - lower Estrogen mimic in Vertebrates: feminizes males - lower

sperm count; alters behaviorsperm count; alters behavior Human HealthHuman Health

decreased mental function decreased mental function male infertilitymale infertilitycancercancer

Organic Pollutants - DDTOrganic Pollutants - DDT

Unintentional Pathways:

Organic Pollutants - DDTOrganic Pollutants - DDT

Problems with DDT (and other pesticides)Problems with DDT (and other pesticides)Evolution of resistance Evolution of resistance Non-target species and creation of new pestsNon-target species and creation of new pests

SedimentsSediments

Sediment from erosion and runoff:Sediment from erosion and runoff:Fills lakesFills lakesObstructs shipping channelsObstructs shipping channelsClogs hydroelectric turbinesClogs hydroelectric turbinesPurification more costlyPurification more costly

ThermalThermal

Major categories of water pollutantsCategory Examples Sources

A. Causes health problems1. Infectious agents Bacteria, viruses, parasites Human and animal excreta2. Organic chemicals Pesticides, plastics, oil, gas,

detergentsIndustrial, household, and farm use

3. Inorganic chemicals Acids, caustics, salts, metals Industrial effluents, householdcleansers, surface runoff.

4. Radioactive materials Uranium, thorium, cesium,iodine, radon

Mining/processing ores, power plants,weapons, natural sources

B. Causes ecosystem disruption1. Sediment Soil, silt Land erosion2. O2-demanding wastes Animal manure and plant

residuesSewage, agricultural runoff, paper

mills, food processing3. Thermal Heat Power plants, industrial cooling

Thermal Pollution = an increase in temperatureThermal Pollution = an increase in temperature

Can cause:Can cause: thermal shock thermal shock parasites and disease parasites and disease greater vulnerability to toxic pollutantsgreater vulnerability to toxic pollutants

Specific Sources of Ground Water PollutionSpecific Sources of Ground Water Pollution

(rate of breakdown is extremely slow in ground water)

• Industrial waste into aquifer recharge zone• Surface runoff into abandoned wells - industry, agriculture,

home• Leaking underground storage tanks of gas stations • Leaking septic tank into recharge area.• Injection wells for secondary recovery.

Point Source:Point Source: discharge of discharge of pollutants from single point. pollutants from single point. Factories, power plants, sewage Factories, power plants, sewage treatment plants, oil wells. treatment plants, oil wells.

Non-point Source:Non-point Source: sources of water sources of water pollution that are scattered or pollution that are scattered or diffuse, not having a specific diffuse, not having a specific location. Farm fields, golf location. Farm fields, golf courses, lawns, cities, roads, courses, lawns, cities, roads, clearcut forests, minesclearcut forests, mines

Water Pollution ControlWater Pollution Control

Reduce the sources Reduce the sources of water pollutionof water pollution

Water Pollution ControlWater Pollution Control

Agriculture is the biggest source of water Agriculture is the biggest source of water pollutionpollution.

Improved water quality has been one of the biggest success stories of the environmental movement.

Improved Water Improved Water QualityQuality

Chesapeake BayChesapeake Bay - America’s largest estuary. - America’s largest estuary.

• reducing nutrient loadingreducing nutrient loading• banning phosphate detergentsbanning phosphate detergents• restoring seagrass and wetlands. restoring seagrass and wetlands.

• upgrading wastewater treatment plantsupgrading wastewater treatment plants

WWT Physical, Chemical, Biological, WWT Physical, Chemical, Biological, Advanced WWTAdvanced WWT

Primary treatment: physical separation of solidsSecondary treatment: aeration tank, biodegradationTertiary treatment: remove phosphates/nitrates

lagoon/marsh or trickling filter. Bioremediation: use of organisms to remove

water pollutants

Septic Tanks Septic Tanks and Drain and Drain

Fields.Fields.

Domestic Sewage TreatmentDomestic Sewage Treatment

Are Conventional Methods of WW treatment suitable for India

• Waste Stabilization Ponds

• Artificial wet lands

• Anaerobic WWT

• UASB

• Eucalyptus plantation