evs- soil pollution

SOIL POLLUTIONSOIL POLLUTION

ByBy

Dr. Abhijit MukherjeeDr. Abhijit Mukherjee

Definition of soil Definition of soil

Soil is a thin layer of material on the Soil is a thin layer of material on the Earth's surface in which plants have their Earth's surface in which plants have their roots. It is made up of many things, such roots. It is made up of many things, such as weathered rock and decayed plant and as weathered rock and decayed plant and animal matter. Soil is formed over a long animal matter. Soil is formed over a long period of time. period of time.

Soil TypesSoil Types

Sand ClaySilt

Chalk Loam Peat Soil

Soil Pollution: Soil Pollution: The introduction of The introduction of

substances, biological substances, biological organisms, or energy organisms, or energy into the soil, resulting into the soil, resulting in a change of the soil in a change of the soil quality, which is likely quality, which is likely to affect the normal to affect the normal use of the soil or use of the soil or endangering public endangering public health and the living health and the living environmentenvironment..

Pollutant on surface of soilPollutant on surface of soil

When any liquid pollutant is on When any liquid pollutant is on or just below the ground surface or just below the ground surface for any period of time, one of for any period of time, one of three things could happen to it, three things could happen to it, if it is not cleaned up first. if it is not cleaned up first. 1: pollutant might be washed away by 1: pollutant might be washed away by

precipitation, causing little or no precipitation, causing little or no harm to the ground on which it was harm to the ground on which it was found ( however, pollutants will found ( however, pollutants will simply accumulate somewhere simply accumulate somewhere else) else)

2: the pollutant, if volatile, 2: the pollutant, if volatile, could evaporate, again could evaporate, again causing little harm to the causing little harm to the soil ( however, not a soil ( however, not a solution to the bigger solution to the bigger pollution problem, as it pollution problem, as it might become a source might become a source of air pollution)of air pollution)

3: pollutant could infiltrate 3: pollutant could infiltrate through the unsaturated through the unsaturated soil, in much the same soil, in much the same way as groundwater.way as groundwater.

Causes of Soil PollutionCauses of Soil Pollution

1.1. MiningMining

2.2. Deforestation Deforestation

3.3. Agricultural ActivitiesAgricultural Activities

4.4. Invasive unwanted life-formsInvasive unwanted life-forms

5. Industrial activities5. Industrial activities

1.1. Mining Processes Mining Processes

i)i) Surface MiningSurface MiningBy removing (stripping) surface vegetation, By removing (stripping) surface vegetation, dirt, and if necessary, layers of bedrock in order dirt, and if necessary, layers of bedrock in order to reach buried ore deposits. to reach buried ore deposits.

(a)(a) Open pit miningOpen pit mining: recovery of materials from : recovery of materials from an open pit in the groundan open pit in the ground

(b) Strip mining(b) Strip mining: stripping surface layers off to : stripping surface layers off to reveal ore underneath reveal ore underneath

(c) Mountaintop removal(c) Mountaintop removal: involves taking the top : involves taking the top of a mountain off to reach ore deposits at of a mountain off to reach ore deposits at depth. depth.

An open pit mine operated by the giant Indian firm Tata at the company's West Bokaro site in Jharkhand

ii)ii) Subsurface MiningSubsurface MiningBy digging tunnels or shafts into the earth to By digging tunnels or shafts into the earth to reach buried ore deposits. reach buried ore deposits.

(a)(a) Drift miningDrift mining: utilizes horizontal access tunnels: utilizes horizontal access tunnels

(b)(b) Slope miningSlope mining: uses diagonally sloping access : uses diagonally sloping access shaftsshafts

(c)(c) Shaft miningShaft mining: consists of vertical access : consists of vertical access shafts shafts

1. Mining Processes …….1. Mining Processes …….

1. Mining :- Effects of Mining1. Mining :- Effects of Mining

Mine spoils and tailingsMine spoils and tailings Strip mining of copper producesStrip mining of copper produces

-100 – 10,000 mg/kg cadmium and lead -100 – 10,000 mg/kg cadmium and lead

- Iron pyrites (FeS- Iron pyrites (FeS22) - devastating effect on aquatic ) - devastating effect on aquatic environmentenvironment

Gold mining produces residual levels of CN- complexes. Producing a single gold ring generates 20 ton of mining waste.

1. Mining - Effects of Mining 1. Mining - Effects of Mining ……

Smelting and refining processes require very high Smelting and refining processes require very high temperature to reduce the metal ores-temperature to reduce the metal ores-Eg. Pyrite – iron, Bauxite - aluminiumEg. Pyrite – iron, Bauxite - aluminium

At these high temperatures, many metals and At these high temperatures, many metals and metal compounds volatilize. metal compounds volatilize.

In coal mining methane gases are released In coal mining methane gases are released

(causing a greenhouse effect)(causing a greenhouse effect)

2. Deforestation2. Deforestation

DeforestationDeforestation is is the clearance of the clearance of forests by logging forests by logging and/or burning and/or burning (popularly known (popularly known as slash and as slash and burn). burn).

2. Deforestation - Causes2. Deforestation - Causes

Urban and Construction PurposesUrban and Construction Purposes To Grow CropsTo Grow Crops To Create Grazing LandTo Create Grazing Land Used for FuelUsed for Fuel Oil and mining exploitationOil and mining exploitation To make highways and roads To make highways and roads Slash and burn farming techniquesSlash and burn farming techniques Wildfires Wildfires Acid rainAcid rain

2. Deforestation - Environmental 2. Deforestation - Environmental Problems CausedProblems Caused

Soil ErosionSoil Erosion

Disruption of the Water CycleDisruption of the Water Cycle

Loss of BiodiversityLoss of Biodiversity

Flooding and DroughtFlooding and Drought

Emission of greenhouse gasesEmission of greenhouse gases

2. Deforestation - Soil Erosion2. Deforestation - Soil Erosion

Soil erosionSoil erosion is the process by which is the process by which soil is moved. soil is moved.

- Natural Erosion- Natural Erosion

- Accelerated Erosion – human - Accelerated Erosion – human interventionintervention

2. Deforestation - Causes of Soil 2. Deforestation - Causes of Soil ErosionErosion

1. Wind erosion1. Wind erosion

2. Water erosion2. Water erosion

3. Glacier erosion3. Glacier erosion

4. Land Slide4. Land Slide

2. Deforestation - Causes of Soil 2. Deforestation - Causes of Soil Erosion …Erosion …

Wind ErosionWind Erosion

- causes air pollution, produces - causes air pollution, produces highway safety hazards, and fills highway safety hazards, and fills drainage ditches.drainage ditches.

- soil is moved by - soil is moved by suspension,suspension, saltationsaltation and and surface creepsurface creep..


Wind Erosion …Wind Erosion …


Water ErosionWater Erosion

1.1. Splash ErosionSplash Erosion

2.2. Sheet ErosionSheet Erosion

3.3. Rill ErosionRill Erosion

4.4. Gulley ErosionGulley Erosion

Splash Erosion

3. Agricultural Activities3. Agricultural Activities

FertilizersFertilizers

PesticidesPesticides

3. Agricultural Activities - 3. Agricultural Activities - FertilizersFertilizers

WhyWhy16 essential 16 essential elements elements required for the growth of required for the growth of all plants: C, H, O, N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, all plants: C, H, O, N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, Mo, B, and Cl in various ionic forms.Mo, B, and Cl in various ionic forms.

However, excessive cropping and in particular However, excessive cropping and in particular dense monoculture practices deplete soil plant dense monoculture practices deplete soil plant nutrients, especially N, P, K, and Ca.nutrients, especially N, P, K, and Ca.

Therefore, N, P, K, and other plant nutrients must Therefore, N, P, K, and other plant nutrients must be periodically augmented by the use of fertilizersbe periodically augmented by the use of fertilizers

3. Agricultural Activities - 3. Agricultural Activities - FertilizersFertilizers

The ProblemThe ProblemOveruse of fertilizers reduce quantity of Overuse of fertilizers reduce quantity of vegetables and crops grown on soil over the years.vegetables and crops grown on soil over the years.

It also reduces protein content of maize, wheat, It also reduces protein content of maize, wheat, gram etc.gram etc.

Excess potassium content in soil decreases Excess potassium content in soil decreases Vitamin C and carotene content in vegetables and Vitamin C and carotene content in vegetables and fruits.fruits.

The vegetables and fruits grown over an over-The vegetables and fruits grown over an over-fertilized soil are more prone to attacks by insects. fertilized soil are more prone to attacks by insects.

3. Agricultural Activities - 3. Agricultural Activities - FertilizerFertilizer

3. Agricultural Activities - 3. Agricultural Activities - PesticidesPesticides

It is any substance or mixture of substances It is any substance or mixture of substances intended for preventing, destroying, repelling or intended for preventing, destroying, repelling or mitigating any pest.mitigating any pest.

-Insecticide: DDT, chlorpyrifos, malathion etc.Insecticide: DDT, chlorpyrifos, malathion etc.

-Herbicide: Glyphosate, atrazine etc.Herbicide: Glyphosate, atrazine etc.

-Fungicide: Chloropicrin, metam-sodium,Fungicide: Chloropicrin, metam-sodium,

1,3-dichloropropene etc.1,3-dichloropropene etc.

3. Agricultural Activities - Fate of 3. Agricultural Activities - Fate of PesticidesPesticides

3. 3. Agricultural Activities - Effects of Agricultural Activities - Effects of

Pesticides on Non-Target OrganismsPesticides on Non-Target Organisms

a. Tremendous diversity of soil organisms - few a. Tremendous diversity of soil organisms - few pesticides kill allpesticides kill all

b. Population of sensitive organisms - may take 1-2 b. Population of sensitive organisms - may take 1-2 yrs. to recover yrs. to recover

c. Earthworms may bioaccumulate - affects their c. Earthworms may bioaccumulate - affects their predators (birds) - DDT, Pbpredators (birds) - DDT, Pb

d. Pesticides have little effect on bacteria - except d. Pesticides have little effect on bacteria - except for nitrifiersfor nitrifiers

3. Agricultural Activities – Soil 3. Agricultural Activities – Soil Acidity and SalinityAcidity and Salinity

Soil AciditySoil Acidity Acid rainAcid rain

Natural acid soils are usually found in the Natural acid soils are usually found in the tropics, the result of thousands of years of tropics, the result of thousands of years of excessive weathering of soil minerals.excessive weathering of soil minerals.

Agricultural soils can also become acidic Agricultural soils can also become acidic due to the continuous additions of large due to the continuous additions of large amounts of acid-forming fertilizers such as amounts of acid-forming fertilizers such as ammonia and urea.ammonia and urea.

3. Agricultural Activities – Soil 3. Agricultural Activities – Soil Acidity and SalinityAcidity and Salinity

Soil SalinitySoil Salinity Soil salinity is a measure of the minerals and salts Soil salinity is a measure of the minerals and salts

that can be dissolved in water. that can be dissolved in water.

NaNa++, Cl, Cl--, SO, SO442-2-, HCO, HCO33

--, K, K++, Mg, Mg++++, NO, NO33--

Excess soil salinity causes poor and spotty stands Excess soil salinity causes poor and spotty stands of crops, uneven and stunted growth and poor of crops, uneven and stunted growth and poor yields. yields.

The primary effect of excess salinity is that it The primary effect of excess salinity is that it renders less water available to plants because of renders less water available to plants because of the increased osmotic pressure of the soil solution. the increased osmotic pressure of the soil solution.

Raichur Thermal Power Plant

5. Industrial Activities …5. Industrial Activities …

Fly ash Pond of Raichur


Spreading of pond Spreading of pond ashash

Stone pitching for Stone pitching for slope protectionslope protection


Mixing of lime Mixing of lime stabilised pond ashstabilised pond ash

Compaction of Compaction of stabilised pond ash stabilised pond ash

using road rollerusing road roller


Control of Soil PollutionControl of Soil Pollution

Reducing usage of fertilizer and pesticidesReducing usage of fertilizer and pesticides

Reusing of materialsReusing of materials

Recycling and recovery of materialsRecycling and recovery of materials

Aforestation and ReforestationAforestation and Reforestation

Soil remediationSoil remediation

Soil RemediationSoil Remediation

TechnologiesTechnologies(1)(1) ContainmentContainment, where the contaminant is , where the contaminant is

restricted to a specified domain to prevent further restricted to a specified domain to prevent further spreading; spreading;

(2)(2) RemovalRemoval, where the contaminant is transferred , where the contaminant is transferred from an open to a controlled environment; from an open to a controlled environment;

(3)(3) TreatmentTreatment, where the contaminant is , where the contaminant is transformed into a nonhazardous substance. transformed into a nonhazardous substance.

Soil Remediation …Soil Remediation …

1.1. ContainmentContainment

- - Physical BarriersPhysical Barriers

- Hydraulic Barriers- Hydraulic Barriers


Physical Barriers

There are three major types of physical barriers: slurrywalls, grout curtains and sheet piling.


Hydraulic Barrier


2.2. RemovalRemoval

- Excavation- Excavation

- Pump-and-Treat- Pump-and-Treat

- Enhanced Flushing (injection of reagent solution)- Enhanced Flushing (injection of reagent solution)

- Soil Venting- Soil Venting

- Thermal treatment- Thermal treatment

ExcavationExcavation

Pump-and-Treat processPump-and-Treat process


3. Treatment3. Treatment

- Biological (Bioremediation)- Biological (Bioremediation)

- Aerobic- Aerobic

- Anaerobic- Anaerobic

- Cometabolic- Cometabolic

- Chemical- Chemical


BioremediationBioremediation Bioremediation can be defined as any process Bioremediation can be defined as any process

that uses microorganisms, fungi, green plants that uses microorganisms, fungi, green plants or their enzymes to return the natural or their enzymes to return the natural environment altered by contaminants to its environment altered by contaminants to its original condition. original condition.

Bioremediation may be employed to attack Bioremediation may be employed to attack specific soil contaminants, such as degradation specific soil contaminants, such as degradation of chlorinated hydrocarbons by bacteria.of chlorinated hydrocarbons by bacteria.


Aerobic mineralization of organic compound


In situ bioremediation


Phytoremediation

PhytoremediationPhytoremediationMetals/SaltsMetals/Salts PlantPlant

ArsenicArsenic Sunflower (Sunflower (Helianthus Helianthus annuusannuus))

CadmiumCadmium Willow (Willow (Salix viminalisSalix viminalis))

Cadmium and ZincCadmium and Zinc Alpine pennycress Alpine pennycress ((Thlaspi caerulescensThlaspi caerulescens))

LeadLead Indian Mustard (Indian Mustard (Brassica Brassica junceajuncea))

Sodium ChlorideSodium Chloride BarleyBarley ( (Hordeum vulgareHordeum vulgare))

Caesium-137 and Caesium-137 and Strontium-90Strontium-90

Sunflower (Sunflower (Helianthus Helianthus annuusannuus))

evs- soil pollution

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