MODULE 3
SOLID WASTE: Classification and sources
of Solid
Waste,
Characteristics of Solid Waste, e waste, Radioactive wastes
LAND/SOIL POLLUTION: Effects of urbanization on land degradation,
Impact of Modern Agriculture on Soil, pesticide pollution, Effect on
Environment
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SOLID WASTE
Solid wastes are all the wastes arising from human and animal activities that are
normally solid and that are discarded as useless or unwanted.
There are mainly three general categories of solid waste:
(1) Municipal Wastes
(2) Industrial Wastes
(3) Hazardous Wastes
Municipal Wastes
Municipal wastes, commonly known as trash or garbage, are a waste type consisting
of everyday items that are discarded by the public. The following table shows the
classification of various materials comprising the municipal solid wastes:
Components
Description
The animal, fruit, vegetable residues (also called garbage)
Food wastes
resulting from the handling, preparation, cooking and eating of
foods. Because food wastes are putrescible, they will
decompose rapidly, especially in warm weather
Rubbish
Combustible and non-combustible solid wastes, excluding
food wastes or other putrescible materials. Typically,
combustible rubbish consists of materials such as paper,
cardboard, plastics, textiles, rubber, leather, wood, furniture,
and garden trimmings. Noncombustible rubbish consists of
items such as glass, crockery, tin cans, aluminium cans, ferrous
and nonferrous metals, dirt and construction wastes
Ashes
Residues
and Materials remaining from the burning of wood, coal, coke and
other combustible wastes. Residues from power plants
normally are not included in this category. Ashes and residues
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are normally composed of fine, powdery materials, cinders,
clinkers and small amounts of burned and partially burned
materials
Demolition and Wastes from razed buildings and other structures are classified
construction
as demolition wastes. Wastes from construction, remodeling,
wastes
and repairing of residential, commercial, and industrial
buildings and similar structures are classified as construction
wastes. These wastes may include dirt, stones, concrete, bricks,
plaster, lumber, shingles and plumbing, heating, and electrical
parts
Special wastes
Wastes such as street sweepings, roadside litter, catch-basin
debris, dead animals, and abandoned vehicles are classified as
special wastes
Treatment-plant
The solid and semi-solid wastes from water, waste-water and
wastes
industrial waste treatment facilities are included in this
classification
Industrial Wastes
Industrial wastes are those wastes arising from industrial activities and typically
include rubbish, ashes, demolition and construction wastes, special wastes, and
hazardous wastes.
Hazardous Wastes
Wastes that pose a substantial danger immediately or over a period of time to human,
plant, or animal life are classified as hazardous wastes. A waste is classified as
hazardous if it exhibits any of the following characteristics:
(1) Ignitability (that would cause fire during transport, storage or disposal)
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(2) Corrosivity (that can react dangerously with other wastes or cause toxic
contaminants to migrate from certain wastes)
(3) Reactivity (posing an explosive problem at any stage of the waste
management
cycle)
(4) Toxicity
Hazardous wastes were often grouped into the following categories:
(1) Radioactive Substances: these are substances that emit ionising radiation
(2) Chemicals: include synthetic, organic and inorganic metals, salts, acids and
bases.
(3) Biological Wastes: wastes from hospitals, biological research facilities etc.
(4) Flammable Wastes: maybe in solid, liquid or gaseous form. Eg: organic
solvents, oils, plasticisers etc.
(5) Explosives: waste resulting from manufacturing of weapons and industrial gases
CLASSIFICATION ACCORDING TO DECOMPOSABILITY:
• Biodegradable
Wastes which can be decomposed by natural processes
Eg: kitchen garbage, paper, wood etc.
• Non-biodegradable
These wastes cannot be degraded and remain as such in the environment.
Eg: plastics, cans, glass etc
CLASSIFICATION ACCORDING TO SAFETY LEVEL:
• Hazardous waste
• Non-hazardous wastes
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CLASSIFICATION ACCORDING TO PHYSICAL CHARACTERISTICS
• Putrescible Solid Wastes
Solid wastes that are easily decomposed by bacterial action. It consists of food
wastes. These may act as good fertilizer or soil conditioners or as animal feed.
• Non-putrescible Solid Wastes
These cannot be easily decomposed by microbial action. It consist of both
combustible and non-combustible substances such as cans, paper, brush, etc. It
causes aesthetic problem when handled carelessly.
SOURCES OF SOLID WASTES
Municipal Solid Wastes
The general sources of municipal solid wastes are as follows:
Source
Typical facilities, activities, or
Locations
where
wastes
Types of solid wastes
are
generated
Residential
Single-family
and
multifamily Food wastes, rubbish, ashes,
dwellings,
Low-,
special wastes.
medium-,
and
high-rise
apartments ,etc.
Commercial
Stores, restaurants, markets, office Food wastes, rubbish, ashes,
buildings, hotels, motels, print shops, demolition and construction
auto repair shops, medical facilities wastes,
and institutions, etc.
Open areas
special
wastes,
occasionally hazardous wastes
Streets, alleys, parks, vacant lots, Special wastes, rubbish.
playgrounds,
beaches,
highways,
recreational areas, etc.
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Treatment
Water, wastewater, and industrial Treatment-plant
plant sites
treatment processes, etc.
principally
wastes,
composed
residual sludges.
Industrial Solid Wastes
The major generators of industrial solid wastes are thermal power plants producing
coal ash, iron and steel mills producing blast furnace slag and non-ferrous industries
like Al, Zn, Cu producing red mud, sugar industries generating press mud, paper and
pulp industries producing lime and fertilizer industries producing gypsum. The
sources of some major industrial wastes are as follows:
Waste generated
Sources/Origin
Steel and Blast furnace Conversion of pig iron to steel
Brine mud
Caustic soda industry
Copper slag
By product from smelting of copper
Fly ash
Coal based thermal power plants
Kiln dust
Cement plants
Lime sludge
Sugar, paper, fertilisers etc
Red mud/ Bauxite
Mining
Limestone wastes
Limestone quarry
Hazardous Solid Wastes
Sources
Examples
Agricultural land and Pesticides, fertilisers and hazardous veterinary product
agro-industry
wastes
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of
Batteries and dry cells, furniture polishes, wood
Domestic
Mines
preservatives, paints, rat poisons, mosquito repellants
and
mineral
processing sites
Health care facilities
Commercial wastes
Institutional wastes
Industrial wastes
Solid
waste
disposal
sites
Mineral dust and powdery materials
Pathological waste, human blood, contaminated needles
Gasoline stations, dry cleaners and automobile repair
shops
Research laboratories, military installations
Petroleum fuel industry, phenols, cyanides, sludge from
storage tanks
Leachate wastes
Contaminated sites
Spills
Building materials
Asbestos, copper, roofing and flooring materials
CHARACTERISTICS OF SOLID WASTES
Information on the properties of solid wastes is important in evaluating alternative
equipment needs, systems, and management programs and plans, especially with
respect to the implementation of disposal and resource- and energy-recovery
options.
I. Physical Composition
1. Individual components
Determination of the various individual components that make up solid waste
is important in the selection of various equipments and facilities, feasibility of
resource and energy recovery and analysis and disposal facilities.
2. Particle size and distribution
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The size of the component materials in solid wastes is of importance in the
recovery of materials, especially when using mechanical equipments. The size
of a waste component may be determined by the following measures:
(a) Sc = L
(b) Sc =
L +W
2
(c) Sc =
L +W + H
3
1
(d) Sc = ( L W  H ) 3
1
(e) Sc = ( L W ) 2
Where Sc = size of the component (mm)
L = length (mm)
W = width (mm)
H = height (mm)
3. Moisture content
The moisture content of solid wastes is defined as the mass of moisture per
unit mass of wet or dry material.
Moisture content (%) =
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑚𝑜𝑖𝑠𝑡𝑢𝑟𝑒
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑠𝑜𝑙𝑖𝑑𝑠
𝑥 100
In the wet-mass method of measurement:
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑚𝑜𝑖𝑠𝑡𝑢𝑟𝑒
Moisture content (%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝑤𝑒𝑡 𝑠𝑜𝑙𝑖𝑑𝑠 𝑥 100
In the dry-mass method:
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑚𝑜𝑖𝑠𝑡𝑢𝑟𝑒
Moisture content (%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝑑𝑟𝑦 𝑠𝑜𝑙𝑖𝑑𝑠 𝑥 100
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Moisture content(%) =
𝑎−𝑏
𝑎
𝑥 100
Where a = wet weight
b = dry weight
In the above method, the wet weight is obtained by weighing the entire sample as
obtained. It is then dried in an oven at 105°C for 24hrs to obtain the dry weight.
For most municipal solid wastes, the moisture content will vary from 15-40%,
depending on the composition of the wastes, season of the year and humidity and
weather conditions(especially rain).
4. Density
It is defined as the weight of the material per unit volume, expressed as
tons/m³ or kg/m³ and specified as loose (discarded), uncompacted or
compacted. The determination of density is essential as:
• Total volume and mass of waste to be managed should be known
• For selecting disposal method, processing units, transportation and
estimation of capacity of disposal sites.
The density of solid waste vary with
• Geographic location
• Season of the year
• Length of time in storage
The densities of municipal solid wastes vary from 178-415 kg/m³ (usually
297kg/m³).
Compacted Density
It is measured using a cubical container of 60cm x 60cm x 60cm. it is filled
to overflow with waste and then tamped thrice by lifting it 6cm above
ground and dropping. It is then levelled and weighed.
𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤𝑎𝑠𝑡𝑒
Compacted density = 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑜𝑛𝑡𝑎𝑖𝑛𝑒𝑟
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Discarded density =
Ma + Mb
Ma Mb 
+

 b 
 a
Where a, b = components of waste
Ma and Mb are mass of a and b
ρa and ρb are densities of a and b
5. Field capacity
It is the total amount of moisture that can be held in a waste sample under
gravitational force. Moisture in excess of field capacity is released as leachate.
The field capacity values range from 50-60% of total weight.
6. Permeability
It is also known as Hydraulic Conductivity. It is defined as the ease with which
a fluid can flow through the waste. The factor is important to determine the
movement of liquids and gases in landfills. It is affected by shape and size of
waste components, porosity, amount of compaction applied etc.
II. Chemical Composition
The information on chemical composition is required for selection of proper
treatment or disposal mehtods, evaluating alternative processing methods, recycling
and energy recovery methods etc.
Eg: feasibility of combustion depends on chemical composition choice of
combustion (incineration) depends on chemical composition.
If solid wastes are to be used as fuel, the four most important properties to be known
are:
1. Proximate analysis
It is done for combustible components of municipal solid wastes. It includes:
• Moisture(loss of moisture when heated at 150°C for 24hrs)
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• Volatile matter(additional loss of weight on ignition at 950°C in a covered
crucible)
• Fixed carbon(combustible residue left after volatile matter is removed)
• Ash(weight of residue after combustion in an open crucible)
2. Fusing point of ash
It is defined as the temperature at which the ash resulting from burning of
waste will form solid clinkers by fusion and agglomeration. The typical value
ranges from 1100-1200°C
3. Ultimate analysis
The ultimate analysis of a waste component typically involves the
determination of the percent of C(carbon), H(hydrogen), O(oxygen),
N(nitrogen), S(sulfur), and ash. It is mainly essential to characterise the
chemical composition of organic matter.
Energy Content
It refers to the net calorific value of waste. Ti is defined as the heat produced by a
unit quantity of waste at a constant volume and at a constant pressure of 1 atm. It is
usually expressed as KJ/kg.
𝑇𝑜𝑡𝑎𝑙 𝐸𝑛𝑒𝑟𝑔𝑦
Energy Content = 𝑇𝑜𝑡𝑎𝑙 𝑄𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑜𝑓 𝑤𝑎𝑠𝑡𝑒
On dry basis:
Energy Content = Total energy content 
100

100 − %moisture 
On ash free basis:
Energy Content = Total energy content 
100

100 − %ash − %moisture 
where the percentage of ash varies from 4-5%.
Chemical Content
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The chemical composition of the individual components such as carbon, hydrogen,
oxygen, nitrogen, sulphur and ash can be determined from the modified Dulong
formula:
O
8
Energy content (KJ/kg) = 337C + 1428( H − ) + 9S
where C=carbon percent
H=hydrogen percent
O=oxygen percent, S=sulphur percent
E-WASTES
Electronic Waste, also recognized as E-Waste, is a combination of used or unwanted
electronic products that have exceeded their end life. "Electronic waste" or "EWaste" may be defined as discarded computers, office electronic equipment,
entertainment device electronics, mobile phones, television sets, and refrigerators.
This includes used electronics which are destined for reuse, resale, salvage,
recycling, or disposal.
SOURCES OF E-WASTE
Telecommunication Waste
Includes telecommunication equipments such as Telephones, Printers, Personal
computers (CPU, mouse, screen and keyboard included), Laptop computer,
Networking equipment, Scanners, Mobile phones, CD / DVDs / Floppy Disks,
UPSs, Radio sets, Television sets, Video cameras, Video recorders ,Audio
amplifiers, Musical instruments Etc.\
Electrical waste
Switches, Relays, Connectors and related scrap material
Electronic Waste
Electronic metal wastes, Printed Circuit Boards, IC, Sockets and Connectors
Cable Waste
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Preinsulated copper and aluminium waste, PVC
ELECTRICAL AND ELECTRONIC EQUIPMENTS AS E-WASTE
Office electronics
Includes Photocopying equipment, Electrical and electronic typewriters, Pocket and
desk calculators, Telephones etc
Large Household Appliances
Includes Refrigerators, Freezers, Washing machines, Dish washing machines,
Microwave Oven, Electric heating appliances Electric hot plates, Electric radiators,
Electric fans, Air conditioner appliances, exhaust ventilation and conditioning
equipment etc.
Small Household Appliances
Vacuum cleaners, Carpet sweepers, Water dispensers, Toasters, Fryers, Appliances
for hair cutting, hair drying brushing teeth, shaving and massage, Electric knives,
Clocks,
Appliances used for sewing, knitting and weaving etc
Consumer Equipment
Includes equipment for turning, milling, sanding, grinding, sawing, cutting,
shearing, drilling, punching, folding, bending or processing wood, metal and other
materials. Tools for riveting, nailing or screwing or removing rivets, nails, screws or
similar uses. Tools for welding, soldering or similar use, Sewing machines etc.
Toys, leisure and sports equipment
Includes Electric trains or car racing sets ,Hand-held video game, Video games,
Computers for biking, diving, running, rowing, etc.,
Lighting
Includes Fluorescent tubes, Compact fluorescent lamps ,High intensity discharge
lamps, including pressure sodium lamps and metal halide lamps, Low pressure
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sodium lamps, Other lighting or equipment for the purpose of spreading or
controlling light.
Medical equipment
Includes Scanners, Operating equipment, Stethoscopes, Radiotherapy equipment,
Cardiology, Dialysis, Pulmonary ventilators, Nuclear medicine equipment,
Laboratory equipment for in vitro diagnosis, Analysers, Freezers, Other appliances
for detecting, preventing, monitoring, treating, alleviating illness, injury or
disability.
Automatic dispensers
• Appliances which deliver automatically all kind of products.
• Automatic dispensers for tickets, Tea, Coffee vending machines, Automatic
dispensers for money –ATM
Monitoring and control instruments
Smoke detectors, Heating regulators, Thermostats, Measuring, weighing or
adjusting appliances for household or as laboratory equipment ,Other monitoring
and control instruments used in industrial installations (e.g. in control panels)
Batteries ,Lead Batteries, Nickel and Cadmium batteries etc.
RADIO ACTIVE WASTES
Radioactive waste is waste that contains radioactive material. Radioactive waste is
usually a by-product of nuclear power generation and other applications of nuclear
fission or nuclear technology, such as research and medicine. Radioactive waste
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is hazardous to all forms of life and the environment and is regulated by government
agencies in order to protect human health and the environment.
Radioactivity naturally decays over time, so radioactive waste has to be isolated and
confined in appropriate disposal facilities for a sufficient period until it no longer
poses a threat. The time radioactive waste must be stored for depends on the type of
waste and radioactive isotopes. Current approaches to managing radioactive waste
have been segregation and storage for short-lived waste, near-surface disposal for
low and some intermediate level waste, and deep burial or partitioning /
transmutation for the high-level waste.
SOURCES
Radioactive waste comes from a number of sources. In countries with nuclear power
plants, nuclear armament, or nuclear fuel treatment plants, the majority of waste
originates from the nuclear fuel cycle and nuclear weapons reprocessing. Other
sources include medical and industrial wastes, as well as naturally occurring
radioactive materials (NORM) that can be concentrated as a result of the processing
or consumption of coal, oil and gas, and some minerals, as discussed below.
Nuclear fuel cycle
The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear
fuel through a series of differing stages. It consists of steps in the front end, which
are the preparation of the fuel, steps in the service period in which the fuel is used
during reactor operation, and steps in the back end, which are necessary to safely
manage, contain, and either reprocess or dispose of spent nuclear fuel.
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Front end
Waste from the front end of the nuclear fuel cycle is usually alpha-emitting
waste from the extraction of uranium. It often contains radium and its decay
products.
Back end
The back-end of the nuclear fuel cycle, mostly spent fuel rods,
contains fission
products that
emit
and actinides that
emit alpha
particles,
245 thousand
beta
such
and
gamma
radiation,
as uranium-234 (half-life
years), neptunium-237 (2.144 million
years), plutonium-
238 (87.7 years) and americium-241 (432 years), and even sometimes some
neutron emitters such as californium (half-life of 898 years for Cf-251). These
isotopes are formed in nuclear reactors.
Nuclear weapons decommissioning
Waste from nuclear weapons decommissioning is unlikely to contain much beta or
gamma activity other than tritium and americium. It is more likely to contain alphaemitting actinides such as Pu-239 which is a fissile material used in bombs, plus
some material with much higher specific activities.
Legacy waste
Due to historic activities typically related to radium industry, uranium mining, and
military programs, numerous sites contain or are contaminated with radioactivity.
Medicine
Radioactive medical waste tends to contain beta particle and gamma ray emitters. It
can be divided into two main classes. In diagnostic nuclear medicine a number of
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short-lived gamma emitters such as technetium-99m are used. Many of these can be
disposed of by leaving it to decay for a short time before disposal as normal waste.
Industry
Industrial source waste can contain alpha, beta, neutron or gamma emitters. Gamma
emitters are used in radiography while neutron emitting sources are used in a range
of applications, such as oil well logging.[22]
Naturally occurring radioactive material
Substances containing natural radioactivity are known as NORM (Naturally
occurring radioactive material). After human processing that exposes or concentrates
this natural radioactivity (such as mining bringing coal to the surface or burning it
to produce concentrated ash), it becomes technologically enhanced naturally
occurring radioactive material (TENORM). A lot of this waste is alpha particleemitting matter from the decay chains of uranium and thorium.
Coal
Coal contains a small amount of radioactive uranium, barium, thorium and
potassium, but, in the case of pure coal, this is significantly less than the
average concentration of those elements in the Earth's crust. The surrounding
strata, if shale or mudstone, often contain slightly more than average and this
may also be reflected in the ash content of 'dirty' coals.The more active ash
minerals become concentrated in the fly ash precisely because they do not
burn well.The radioactivity of fly ash is about the same as black shale and is
less than phosphate rocks, but is more of a concern because a small amount
of the fly ash ends up in the atmosphere where it can be inhaled.
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Oil and gas
Residues from the oil and gas industry often contain radium and its decay
products. The sulfate scale from an oil well can be very radium rich, while the
water, oil and gas from a well often contain radon. The radon decays to form
solid radioisotopes which form coatings on the inside of pipework. In an oil
processing plant the area of the plant where propane is processed is often one
of the more contaminated areas of the plant as radon has a similar boiling point
to propane.
LAND DEGRADATION
• Land degradation is the most important environmental problem currently
challenging sustainable development in many parts of the world.
• The change in the characteristic and quality of soil which adversely affect its
fertility is called as Degradation.
• The problem is most acute where the environment is intrinsically vulnerable and
where the population is losing control of its own resources.
Land Degradation means
1) Loss of natural fertility of soil because of loss of nutrients.
2) Less vegetation cover
3) Changes in the characteristic of soil.
4) Pollution of water resources from the contamination of soil through which
water sweeps into ground or runoff to the water bodies.
5) Changes in climatic conditions because of unbalance created in the
environment.
Causes of Land Pollution
1)Deforestation and Soil erosion
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Deforestation carried out to create dry lands is one of the major concerns.
Land that is once converted into a dry or barren land, can never be made
fertile again. Exposed land and loosened soil may lead to soil erosion. Land
conversion is another major cause, meaning the alteration or modification of
the original properties of the land to make it use worthy for a specific
purpose.
2)Agricultural activities:
With growing human population, demand for food has increased
considerably. Farmers often use highly toxic fertilizers and pesticides to get
rid off insects, fungi and bacteria from their crops. With the over use of
these chemicals, they result in contamination and poisoning of soil.
3)Industrialization:
Due to increase in demand for food, shelter and house, more goods are
produced. This resulted in creation of more waste that needs to be disposed
of. To meet the demand of the growing population, more industries were
developed which led to deforestation.
4)Construction activities:
Due to urbanization, large amount of construction activities are taking place
which has resulted in large waste articles like wood, metal, bricks, plastic
etc
5)Nuclear waste:
Nuclear plantscan produce huge amount of energy through nuclear fission and
fusion. The left over radioactive material contains harmful and toxic
chemicals that can affect human health. They are dumped beneath the earth
to avoid any casualty.
6)Sewage treatment:
Large amount of solid waste is leftover once the sewage has been treated.
The left over material is sent to landfill site which end up in polluting the
environment.
7)Acid rain:
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Acid rain is caused when pollutants present in the air mixes up with the rain
and fall back on the ground. This polluted water could dissolve away
some of the important nutrients found in soil and change the structure of
the soil.
8)Accidental oil spills:
Chemicals in the fuel deteriorates the quality of soil and make them
unsuitable for cultivation. These chemicals can enter into the groundwater
through soil and make the water undrinkable
9)Mining activities:
A source of land pollution. Huge holes are dug for mining and these holes
can pose a hazard as they form deep mining pools. Metals like cadmium
and lead will be deposited, which are toxic contaminating the soil. This will
leave the mining land barren and unable to use again.
10)Shifting Cultivation
Forest is burnt to use the land for cultivation,until the soil loses it’s fertility.
Once the land becomes inadequate for crop production,it is left barren and
hance leads to soil erosion.
EFFECTS OF URBANIZATION ON LAND POLLUTION
Urbanization is the increased number of inhabitants in the urban areas. The trend of
urbanization has been in its greatest boom since 1980’s. Presently more and more
people flock towards cities for better living conditions and facilities.
This immediate drift towards urbanization has created various environmental issues.
Some of the major effects include
1.Soil erosion : Conversion of agricultural land and forest, as well as reclaiming of
wetlands, for urban uses and infrastructure, are associated with widespread
removal of vegetation to support urban ecosystem which in turn led to soil erosion.
The conversion of Earth's land surface to urban uses is one of the most irreversible
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human impacts on the global biosphere. It drives the loss of farmland, affects local
climate, fragments habitats, and threatens biodiversity.
2.Land slides: The stability of slopes (both natural and artificial) determines the
vulnerability of landslides or slope failures Encroachment of urban land into
nearby forested or vegetated areas, and the expansion of built up areas and
transportation networks into steeper terrain destabilizing slopes lead to slope failures
3.Effect on Climate: The conversion of Earth's land surface to urban uses leads to
loss in the forest cover of Earth which in turn going to affect the amount of rain.
4.Improper waste disposal: Urban activities generate large quantities of city wastes
including several biodegradable materials (like vegetables, animal wastes, papers,
wooden pieces, carcasses, plant twigs, leaves, cloth wastes as well as sweepings)
and many non-biodegradable materials (such as plastic bags, plastic bottles, plastic
wastes, glass bottles, glass pieces, stone / cement pieces). Uncollected and
improperly handled solid waste can have serious health consequences.
• Clogging of drains Causing serious drainage problems including the burst /
leakage of drainage lines leading to health problems.
• Barrier to movement of water -Solid wastes have seriously damaged the normal
movement of water thus creating problem of inundation, damage to foundation
of buildings as well as public health hazards.
• Foul smell - generated by dumping the wastes at a place.
• Increased microbial activities Microbial decomposition of organic wastes
generate large quantities of methane besides many chemicals to pollute the soil
and water flowing on its surface hospital waste
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• Create many health problems - as they may have dangerous pathogen within
them besides dangerous medicines, injections.
• Pollution of underground soil
• Chemicals released by industrial wastes
Decomposed and partially
decomposed materials of sanitary wastes
5.Decrease in food production As the world population and land degradation
increase, world food security decrease.
IMPACT OF MODERN AGRICULTURE ON LAND DEGRADATION
Agriculture is an art, science and industry of managing the growth of plants and
animals for human use. Agriculture includes preparation of soil for cultivation of
crops, harvesting crops, breeding and raising livestock, dairying and forestry.
The two major types of agriculture are:
• Traditional agriculture and
• Modern or Industrialized agriculture
Modern Agriculture
Modern agriculture makes use of hybrid seeds of single crop variety, technologically
advanced equipment, fertilizers, pesticides and water to produce large amounts of
single crop. As agriculture has become more intensive, farmers have become capable
of producing higher yields using less labor and less land. But environmental impacts
have increased, including potential degradation of the soil and water resources vital
to both farm productivity and human health.
1.Deforestation and Soil erosion
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• In agriculture, soil erosion refers to the wearing away of a field's topsoil
by the natural physical forces of water and wind or through forces
associated with farming activities such as tillage.
• Soil compaction, low organic matter, loss of soil structure, poor internal
drainage, salinisation and soil acidity problems are the conditions that
can accelerate the soil erosion process.
• Erosion affects productivity because it removes the surface soils,
containing most of the organic matter, plant nutrients, and fine soil
particles, which help to retain water and nutrients in the root zone where
they are available to plants.
• The subsoil that remains then tend to be less fertile, less absorbent, and
less able to retain pesticides, fertilizers, and other plant nutrients.
2.Damages
• Caused by agricultural machinery in soil
• The use of tractors combined with harvesters increased with suitable
machinery has made easy to work on difficult soils and has brought
such lands under plough.
• This result in soil compaction and is characterized by increased density
of the soil, reduced air volume and a reduced ability to drain off surplus
water.
3)Wrong soil tillage
• Wrong soil tillage with regards of without any concern field location,
soil structure and climate conditions cause soil erosion and results in
inefficient soils.
4) Loss of Soil Fertility
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• The introduction of intensive cultivation to get the maximum
production and the varietyof crops through multiple cropping, crop
rotations, changing crop combination from the same unit of land has
resulted in the decline of the productivity and total production due to
critical limit of the soil.
5)Water logging
• If water stands on land for most of the year, it is called water logging.
In water logged conditions, pore-voids in the soil get filled with water
and soil-air gets depleted. In such a condition the roots of plants do not
get enough air for respiration. Water logging also leads to low
mechanical strength of soil and low crop yield.
6)Excessive use of Fertlizers
• Micronutrient imbalance:
Chemical fertilizers used in modern
agriculture contain Nitrogen, Phosphorus and Potassium (N,P,K)
which are macronutrients. Excess use of fertilizers in fields causes
micronutrient imbalance
• Nitrate pollution: Excess Nitrogenous fertilizers applied in fields leach
deep into the soil contaminating the groundwater. If the concentration
of nitrate in drinking water exceeds 25 mg/L it leads to a fatal 
condition in new-born babies. This condition is termed "Blue Baby
Syndrome"
• Eutrophication: The application of excess fertilizers in fields leads to
wash off of the nutrient loaded water into nearby lakes causing overnourishment. This is called "Eutrophication.
7)Use of Pesticides
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• Death of non-target organisms: Several insecticides kill not only the
target species but also several beneficial not target organisms in the
soil.
Pesticide resistance: Some pests that survive the pesticide
generate highly resistant generations that are immune to all kinds of
pesticides. These pests are called "superpests“ Bio-magnification:
Most pesticides are non-biodegradable and accumulate in the food
chain. This is called bio-accumulation or bio-magnification. These
pesticides in a bio-magnified form are harmful to human beings. Risk
of cancer: Pesticide enhances the risk of cancer in two ways (i) It acts
as a carcinogen and (ii) It indirectly suppresses the immune system
8) Increase in Soil Salinity
• The increase in soil salinity, salinization, is an effect of salt
accumulation in the soil. Irrigation and agricultural processes that
discharge nitrate and phosphate deposits in the soil are the primary
contributors to increasing salt levels in the soil. Increased soil salinity
makes it difficult for plants to absorb soil moisture and reduces
groundwater quality.
Crops and plants grown in these regions
combined with other soil pollutant effects are highly poisonous and can
cause severe health disorders when consumed.
PESTICIDE POLLUTION
A pesticide is a substance or a mixture of substance intended for preventing,
destroying or repelling or lessening the damage caused by the pest.
Classification of pesticide
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1. Herbicide
2. Insecticide
3. Rodenticide
4. Nematicide
5. Molluscicide
6. Fungicide
7. Algaecides
8. Bactericide
9. Piscicide
Pathways of pesticide movement
• Absorbed by crops
• Vapourises to atmosphere
• Degraded by UV light (Photo degradation)
• Deposited by rainfall
• Surface runoff to lakes and rivers
• Leaching and breakdown in soil.
• Leaching and degradation by microbes
Hazards of Pesticides
1)Adverse environmental Impact
• Pesticides causes pollution of soil, water and air.
• The pesticidal residue washed along with rain water, is added to the nearby
water resources making it unfit for drinking.
• Decreases the soil fertility.
• Pesticides are persistant organic pollutants and cause soil pollution.
• They enter the food chain and cause problem of biomagnifications.
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• Several pesticides kill not only the target species but also several beneficial
not target organisms in the soil.
• They are non biodegradable and affects the balance of the ecosystem.
2)Health issues.
• Health issues such as cancer, birth defects, neurological disorders etc which
results from long term exposure to pesticides as well as from food cycle.
3) Development of pest resistance
• Due to overuse of these harmful chemicals, pests have developed resistance
to them. The species that have survived can reproduce a large number of
pesticide resistant offspring within a short span of time. These highly
resistant pests are called "superpests“
CONTROL OF PESTICIDE POLLUTION
• Mechanical methods
• Biological methods
• Environmental methods
• Chemical methods
1)Mechanical methods
• Hand picking: Method of choice when pests are slowly crawling and are not
able to fly e.g caterpillars
• Trapping :Is used for flying pests which cant be picked by hand or burned.
• Burning: Is used for flying pests which cant be picked by hand and can
cause damage. Pests are burned and waste is removed frequently
2)Biological control:
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Unlike chemical method, biological methods will not leave any toxic material in the
soil. In biological pest control method, some natural predators, parasites, viruses and
bacteria are introduced in soil. These control the population of pests that are harmful
to us.
3)Environmental methods:
The surrounding of the pest is changed in such a way it becomes unfavorable for its
growth It can be achieved by removing food stuff needed for the growth of the pest
4)Chemical methods
In this method, certain chemicals are used for controlling pests.
• E.g. Rodenticides, Insecticides, Herbicides, fungicides
EFFECT OF POLLUTION ON ENVIRONMENT AND LIFE
SUSTENANCE
• The contamination or degradation of soils impacts heavily on the health of
plants.
• Humans are also affected in numerous ways either directly or indirectly.
• Polluted soil can harm humans by making contact with the soil or
consuming vegetation produced from contaminated soils.
Some of the effects are detailed as follows.
1.Endangering Human Health
• More than 70% of the soil pollutants are carcinogenic in nature,
intensifying the chances of developing cancer in the humans exposed to the
polluted soils.
• Long term exposure to benzene and polychlorinated biphenyls (PCBs),
resuts in the development of leukemia and liver cancer respectively.
• Soil pollutants can also cause skin diseases, muscular blockage, and
central nervous system disorders. • Humans can be affected indirectly due to
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bioaccumulation or food poisoning. It happens when people consume crops
that are grown in the polluted soils or when they consume animal products
that feed on plants from polluted soils.
• As a result, humans suffer from acute illnesses and may experience
premature death.
2.Economic lossess
• The crops grown in the soils and the nearby lands are often poisoned with
heavy metals and chemicals are, discarded after harvesting because of high
toxicity levels.
• It is considered unfit for human consumption. Consequently, it leads to
enormous economic losses.
3.Air and Water Contamination
• Polluted soil by natural means contributes to air contamination by
discharging volatile compounds into the atmosphere.
• Soil pollution can also lead to water pollution if the toxic chemicals and
materials like dangerous heavy metals leach into groundwater or
contaminate storm water runoff, which reaches lakes, rivers, streams, or
oceans.
4.Effects on Plant life
• When soils are repeatedly contaminated and accumulate large amounts of
poisonous materials and chemicals, the soil reaches a point where it cannot
support plant life.
• Soil pollutants interfere with soil chemistry, biology, and structure.
• When these changes occur, beneficial soil bacteria, soil microorganisms,
soil nutrients, and soil chemical processes begin to deteriorate to an extent
where they diminish soil fertility.
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• The soil becomes unsuitable for crop survival or any other form of
vegetation.
• The plants die and animals dependent on the plants will also die.
• This leads to migration of the larger animals and predators to other regions
to find food supply, gradually leading to a reduction in wildlife and
extinction.
5.Acidification
• Acid rain reduces soil chemistry and nutrients, which would further
contribute to ecological balance disturbance and soil erosion.
6.Diminished soil fertility
• The most evident and crucial element of the soil is its fertility.
• The harmful chemicals and heavy metals in the soil decrease soil microbial
and chemical activity.
• Once the soil is contaminated with chemicals and heavy metals or
degraded due to human activities such as mining, its fertility depreciates and
might even be lost entirely.
7.Increase in soil salinity
The increase in soil salinity, salinization, is an effect of salt accumulation in
the soil. Irrigation and agricultural processes that discharge nitrate and
phosphate deposits in the soil are the primary contributors to increasing salt
levels in the soil. Increased soil salinity makes it difficult for plants to absorb
soil moisture and reduces groundwater quality. Crops and plants grown in
these regions combined with other soil pollutant effects are highly poisonous
and can cause severe health disorders when consumed.
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