Friday, December 12, 2014

Answers to Environmental Studies Questions

Biogas typically refers to a mixture of different gases produced by the breakdown of many organic matter in the absence of some oxygen. Biogas can be produced from regionally available raw materials such as recycled waste. It is a renewable energy source and in many cases exerts a very small carbon footprint.

Biogas is produced by anaerobic digestion with anaerobic bacteria or fermentation of biodegradable materials such as manure, sewage, municipal waste, green waste, plant material, and crops. It is primarily methane and carbon dioxide and may have small amounts of hydrogen sulphide, moisture and siloxanes.

The gases methane, hydrogen, and carbon monoxide can be oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.

Biogas can be compressed, the same way natural gas is compressed to CNG, and used to power motor vehicles. In the UK, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel.

Solar desalination is a technique to desalinate water using solar energy. There are two basic methods of achieving desalination using this technique; direct and indirect.
In the direct method, a solar collector is coupled with a distilling mechanism and the process is carried out in one simple cycle. Water production by direct method solar distillation is proportional to the area of the solar surface and incidence angle. Because of the relatively high cost of property and material for construction direct method distillation tends to favor plants with production capacities less than 200m3/day.

Indirect solar desalination employs two separate systems; a solar collection array, consisting of photovoltaic and/or fluid based thermal collectors, and a separate conventional desalination plant. Production by indirect method is dependent on the efficiency of the plant and the cost per unit produced is generally reduced by an increase in scale. Many different plant arrangements include but are not limited to Multiple Effect Humidification (MEH), Multiple Stage Flash Distillation (MSF), Multiple Effect Distillation (MED), Multiple Effect Boiling (MEB), Humidification Dehumidification (HDH), Reverse Osmosis (RO), and Freeze effect distillation.

Eco-labeling Eco-labels and Green Stickers are labeling systems for food and consumer products. Ecolabels are voluntary, but green stickers are mandated by law. They are a form of sustainability measurement directed at consumers, intended to make it easy to take environmental concerns into account when shopping. Some labels quantify pollution or energy consumption by way of index scores or units of measurement; others simply assert compliance with a set of practices or minimum requirements for sustainability or reduction of harm to the environment.

Ecolabelling systems exist for both food and consumer products. Both systems were started by NGOs, since then the European Union have developed legislation for conduct of ecolabelling and also have created their own ecolabels, one for food and one for consumer products. Label trust is an issue for consumers.


Environmental studies - Introduction, Definition, scope and importance, measuring and defining environmental development indicators
Basic principles of ecosystem functioning - Concept of an ecosystem, structure and function of an ecosystem, producers, consumers and decomposers - energy flow in an ecosystem, food chains, food webs and food pyramids. Introduction, types, characteristic features, structure and function of:
-Forest ecosystem
-Desert ecosystem
-Aquatic ecosystems (ponds, streams, lakes, rivers, estuaries and oceans)
Biodiversity and its conservation - Introduction, Genetic, species and ecosystem diversity. Biogeographical classification of India. Value of biodiversity - consumptive and predictive use, social, ethical and optional value. Biodiversity at global, national and local levels. Hotspots of biodiversity, threats to biodiversity - habitat loss, poaching of wildlife, man-wildlife conflicts, India sa a mega-diversity nation, Endangered and endemic species of India. Conservation of biodiversity (In-situ and ex-situ conservation)

Environment and natural resources - Forest resources (use and over-exploitation), deforestation, timber extraction, mining and dams - their effects on forests and tribal people. Case studies. Water resources use and over-utilization of surface and ground water. Floods, droughts, Conflicts over water, Dams - benefits and demerits. Mineral resources - use and exploitation. Effects of extracting and using mineral resources. Case studies. Food resources - World food problems. Change caused by agriculture and overgrazing. Effects of modern agriculture, fertilizer-pesticide problem, water logging and salinity. Case studies. Energy resources - Growing energy needs, Renewable and non-renewable energy sources, use of alternate energy sources, Case studies. Land resources, Land as a resource, Common property resources, land degradation, soil erosion and desertification.
Environmental valuation - Welfare measure and environmental values, Definition and classification of environmental values, valuation methods,
Environmental Economics - Economic approach to environmental preservation and conservation, property rights and externalities, Management of natural resources, Natural resources accounting, Economics of natural resources - Forests, water resources, fisheries, biodiversity.


Environmental Pollution - Causes, effects and control measures of air pollution, water pollution, soil pollution, marine pollution, noise pollution, nuclear hazards, solid waste management, urban and industrial wastes, pollution case studies,pollution control methods. Disaster management - Floods, Earthquakes, Cyclones and landslides.
Environmental problems in India - Effects of human activities on the quality of life, water and river, ground water, wasteland reclamation. Energy-firewood, animal energy, thermal and nuclear energy. Access to common property resources(CPR), Pollution: Domestic solid waste, Health and sanitation, safe drinking water

Regional and sectoral issues - Urbanization, Agro-forestry, Dry lands, Goods and services, Mountain development, River basin water resource managtement, sustainable tourism, Coastal zone managenment.
Environment and development - The economy and environment interaction, State of the environment - economics of development, preservation and conservation. Sustainability: Theory and practice, Equitable use of resources for sustainable lifestyles. Role of anindividual in pollution prevention.
Human population annd the environment - Population growth and the environment - human rights - VALUE EDUCATION - woman and child welfare - role of information technology - case studies

Social issues and the environment - From unsustainable to sustainable development, Water conservation, rain water harvesting, watershed management. Resettlement and rehabilitation of people - its problems and concerns. case studies; Environmental ethics: issues and possible solutions, consumerism and waste products, public awareness, role of an individual in conservation of natural resources.
Sustainable resource management - Benefits and costs of environmental management, market and non-market benefits, health benefits, recreation benefits, aesthetic benefits, environmental costs, environmental impact assessment - evaluation of project and programs
Design of environmental policy - Direct regulation by government, command and control instruments, economic instruments, pollution taxes, marketable permits, mixed instruments, informal regulation by local communities, monitoring and enforcement of environmental regulation.
Institutions and governance - Evolution of laws, institutions and policies relating to India, popular participation in environment movement environmental activities and ethics that sustain the world
Environment and sustainable development - Concepts and indicators - linkages and trade-offs - indicators of sustainability, Approaches to sustainable development.

Wednesday, December 10, 2014

Question paper for Environmental Studies (9030) On 10 Dec 2014

PART A (Answer all - 25 marks)
What is biogas
What is solar desalination
What are ecological (tedogical) pyramids
What are (sapromorphs) saprotrophs
Define the term wildlife sanctuary
What is a biome
What is noise pollution
Define the term hazardous waste
What is watershed management
What is eco-labeling

PART B (Answer any five - 50 marks
What is earth capital ? Briefly describe the merits and demerits of (Eco thermal) Geo-thermal and Ocean energy resources
Discuss the following problems (i) Deforestation and mining (ii) Overgrazing and modern agriculture with side effects for both.

What is an eco-system. Discuss briefly as to how balance is maintained in an ocean ecosystem
What are ecological pyramids. Explain as to how energy is transferred in an ecosystem with examples

India is a mega-diversity nation. Explain
Write a note on threats to biodiversity

Write about causes, effects and control measures of thermal pollution
What is solid waste. Explain briefly the various methods of disposing solid waste

Differentiate between disaster management and disaster mitigation
Write a note about NDMA and disaster management in India

What is bio-magnification, eutrophication (tetrophication), folsom bottles and macro-consumers
What is silent spring and explain GAIA theory

Write a short note about: (i) Consumerism and waste products (ii) Eco-auditing and (iii) Holocaust

ps: The text in brackets has apperared in the actual question paper. The corrected term is placed "outside" the brackets.

Monday, December 8, 2014

Useful Study technique

Studying More Effectively
Although we are continuously being bombarded with new theories, new ideas all the time from different sources, it is very easy to forget or get confused with what has been read or taught. The 'SQ3R' technique helps study in an appropriate level of detail, and remember information well. It makes reading both more efficient and more effective.
Francis Pleasant Robinson developed SQ3R, and published it in his 1946 book, "Effective Study." SQ3R is an acronym that stands for five steps that you should use when reading something that you want to remember. These five steps are:
Start by skimming through the material to pick up an overview of the text. Next, note down any questions that you may have about the subject. When you question the material, you engage your mind and prepare it for learning. Now read the document, one section at a time. Make a note of anything that you don't understand. While you're reading,  take notes on important concepts, and to record your reactions to what you're reading. "Read actively" by underlining important passages or by using a highlighter pen to show key points. Once you've read the appropriate sections of the document, run through it in your mind several times. Identify the important points, and then work out how other information fits around them. Now, answer the questions from memory. Only turn back to the text if you're unable to answer a question this way.
Once you can recall the information, you can start to review it.
First, reread the document or your notes. This is especially important if you don't feel confident that you've understood all of the information.
Then discuss the material with someone else – this is a highly effective method of reviewing information. Explain what you have just learned as comprehensively as you can, and do your best to put the information into a context that's meaningful for your team, organization, or industry.
Finally, schedule regular reviews of the material to keep it fresh in your mind. Do this after a week, after a month, and after several months – this helps to embed the material into your long-term memory.

Wednesday, November 26, 2014

Disaster Management

Disaster management
A disaster is a sudden, calamitous event that seriously disrupts the functioning of a community or society and causes human, material, and economic or environmental losses that exceed the community’s or society’s ability to cope using its own resources. Though often caused by nature, disasters can have human origins

Disaster Management can be defined as the organization and management of resources and responsibilities for dealing with all humanitarian aspects of emergencies, in particular preparedness, response and recovery in order to lessen the impact of disasters.

Disaster management Is a systematic process of planning, organising, and leading in order to effectively manage the after-effects of a disaster.
It aims to reduce the negative impact or consequences of adverse events

Types of disasters
Disasters can be classified as natural, man-made and human-induced.

Examples of natural disasters are:

Examples of man-made disasters are:
Nuclear leaks (Fukushima nuclear reactor leak)
Chemical leaks / spills
Terrorist activities
Structural collapse

Examples of human-induced disasters are:
Global warming
Drying-up of ural sea (inland sea) in Russia due to water diversion
Large scale deforestation
Large scale biological warfare

Disaster management cycle
Disaster management is an enormous task. Disasters are not confined to any particular location, neither do they disappear as quickly as they appear. Therefore, it is essential that there is proper management to optimize efficiency of planning and response. Due to limited resources, collaborative efforts at the governmental, private and community levels are necessary.

Disaster management, and methodology,
Disaster management is a cyclical process; the end of one phase is the beginning of another
Timely decision making during each phase results in greater preparedness, better warnings, reduced vulnerability and/or the prevention of future disasters.
Mitigation: Measures put in place to minimize the results from a disaster.
Examples: building codes and zoning; vulnerability analyses; public education.
Preparedness: Planning how to respond.
Example: preparedness plans, emergency exercises/training; warning systems.
Response: Initial actions taken as the event takes place. It involves efforts to minimize the hazards created by a disaster.

Examples: evacuation, search and rescue; emergency relief.
Recovery: Returning the community to normal. Ideally, the affected area should be put in a condition equal to or better than it was before the disaster took place.
Examples: temporary housing; grants; medical care.

Disaster management in India.
In order to manage the various kinds of disasters occurring sporadically in various parts of India, The Disaster Management Act, 2005 provides for the constitution of the following institutions at national, state and district levels.
National Disaster Management Authority
State Disaster Management Authorities
District Disaster Management Authorities
National Institute of Disaster Management and
National Disaster Response Force

Disaster prevention
These are activities designed to provide permanent protection from disasters. Not all disasters, particularly natural disasters, can be prevented, but the risk of loss of life and injury can be mitigated with good evacuation plans, environmental planning and design standards. In January 2005, 168 Governments adopted a 10-year global plan for natural disaster risk reduction called the Hyogo Framework. It offers guiding principles, priorities for action, and practical means for achieving disaster resilience for vulnerable communities.

Disaster preparedness
These activities are designed to minimise loss of life and damage – for example by removing people and property from a threatened location and by facilitating timely and effective rescue, relief and rehabilitation. Preparedness is the main way of reducing the impact of disasters. Community-based preparedness and management should be a high priority in physical therapy practice management.

Disaster relief
This is a coordinated multi-agency response to reduce the impact of a disaster and its long-term results. Relief activities include rescue, relocation, providing food and water, preventing disease and disability, repairing vital services such as telecommunications and transport, providing temporary shelter and emergency health care.

Disaster recovery
Once emergency needs have been met and the initial crisis is over, the people affected and the communities that support them are still vulnerable. Recovery activities include rebuilding infrastructure, health care and rehabilitation. These should blend with development activities, such as building human resources for health and developing policies and practices to avoid similar situations in future.

Basic principles of disaster mitigation
Disaster mitigation measures are the measures that eliminate or reduce the impacts and risks of hazards through proactive measures taken before an emergency or disaster occurs. Example: Building of a floodway.
Disaster mitigation measures may be structural (e.g. flood dikes) or non-structural (e.g. land use zoning). Mitigation activities should incorporate the measurement and assessment of the evolving risk environment. Activities may include the creation of comprehensive, pro-active tools that help decide where to focus funding and efforts in risk reduction.
Other examples of mitigation measures include:
Hazard mapping
Adoption and enforcement of land use and zoning practices
Implementing and enforcing building codes
Flood plain mapping
Reinforced tornado safe rooms
Burying of electrical cables to prevent ice build-up
Raising of homes in flood-prone areas
Disaster mitigation public awareness programs
Insurance programs

Tuesday, November 25, 2014

Brain food!!

Brain Food: What to Eat When Revising

A common mistake many students make during this crucial period is to eat poorly and unhealthily. Junk food, lots of chocolate, energy drinks and crisps are often eaten in place of normal meals to “keep energy levels up”. However, this is not only harmful to your long-term health, but can also negatively affect your exam performance.

Here are some brain food recommendations during the most stressful period of your academic year...

Salmon (maga, budatha), sardines (kavallu) and mackerel (vanjiram, peddah-mottah) are amongst the healthiest types of fish because they contain lots of protein and omega 3, which is essential to keep a functioning brain working well.

Eggs are one of the most versatile foods on Planet Earth. Fried, boiled, poached or made sunny-side up, eggs are healthy and good brain food.  One egg contains many nutrients, antioxidants, 6g of protein and less than 100 calories (depending on how you cook it

Vegetables and fruit are also low in calories, delicious and can give you an energy boost when you are working away at revising, since they contain fructose and healthy sugars your body can convert into energy. Top snacking fruits: apples, bananas, avocadoes, berries.

peanut butter actually contains healthy fats and lots of protein per serving. This means that as a brain food , just a little can keep you full for a long time.

Coffee smell will make you feel more awake! And while drinking too much coffee is certainly bad for you, research has also shown that a few cups a day can actually be beneficial. Warning: do not overdose!

Healthy bodies do lead to healthy minds. And having a healthy mind will help you ace that crucial exam or paper.


Saturday, November 1, 2014



The Disaster management cycle illustrates the ongoing process by which governments, businesses, and civil society plan for and reduce the impact of disasters, react during and immediately following a disaster, and take steps to recover after a disaster has occurred. Appropriate actions at all points in the cycle lead to greater preparedness, better warnings, reduced vulnerability or the prevention of disasters during the next iteration of the cycle. The complete disaster management cycle includes the shaping of public policies and plans that either modify the causes of disasters or mitigate their effects on people, property, and infrastructure.

The disaster cycle or the disaster life cycle consists of the steps that emergency managers take in planning for and responding to disasters. Each step in the disaster cycle correlates to part of the ongoing cycle that is emergency management. This disaster cycle is used throughout the emergency management community, from the local to the national and international levels.

The first step of the disaster cycle is usually considered to be preparedness. Prior to a disaster’s occurrence, emergency manager will plan for various disasters which could strike within the area of responsibility.

The second stage in the disaster cycle is response. Imminently prior to a disaster, warnings are issued and evacuations or sheltering in place occurs and necessary equipment is placed at the ready.

After the immediate response phase of the disaster cycle has been completed, the disaster turns toward recovery, focusing on the longer term response to the disaster. During the recovery phase of the disaster cycle, officials are interested in cleanup and rebuilding. During the recovery phase, lessons learned are collected and shared within the emergency response community.

The mitigation phase of the disaster cycle is almost concurrent with the recovery phase. The goal of the mitigation phase is to prevent the same disaster-caused damages from occurring again.

Finally, using the lessons learned from the response, recovery, and mitigation phases of the disaster the emergency manager and government officials return to the preparedness phase and revise their plans and their understanding of the material and human resources needs for a particular disaster in their community.


Developing countries are more prone to disasters than the developed states. As economies develop, there are fewer disaster related deaths and damages. However, increasing wealth causes relatively higher losses in high income nations. Increase in income increases the demand for individual safety, thereby enabling additional costly precautionary measures.
-Not all disasters result in significant ecosystem impact
-Some extreme events have a positive impact on the ecosystem. (floods help rejuvenate floodplain vegetation and are important ecological drivers for many ecological processes in flood plains)
-the non-market impacts due to natural disasters are difficult to quantify (positive impact due to floods)
-Impacts of natural disasters on the environment may be direct, indirect and tangible
              - Direct losses are physical effects that reduce functionality of an individual or structure. This                            includes damage to people, vehicles, buildings, clean-up and disposal costs.
              - Indirect losses affect society by disrupting utility services and local businesses. This includes loss                    of revenue, increased cost, expense incurred due to provision of assistance, lodging and drinking                    water.
              - Intangible losses include psychological impairments due to both direct and indirect losses that                        individuals during the disaster.
-Impacts of natural disasters on infrastructure: These kind of impacts can be quantified. Damage to buildings depends on several factors.
The amount of loss depends upon the condition of the building after the occurrence of the disaster. The building could be:
              - Collapsed
              - Unusable due to structural damage
              - Unusable due to loss of functionality or
              - Habitable with little damage
Damage to roads can affect one or more of the following sub elements(bridge, tunnel or roadway). The damages are listed below:
              - Road breakage causing traffic interruption for days or months
              - Temporary interruption without breakage
              - light damage without traffic interruption
Even in railways as in roadways, the effect depends upon damaged sub-elements. Damages are listed below:
              - Rail breakage causing traffic interruption for days or months
              - Temporary interruption without breakage
              - light damage without traffic interruption
Productive activities include industrial, commercial, handicraft, tourism and farming. The kinds of losses in this category are listed below:
              - Prolonged service interruption of large areas
              - Temporary service interruption of large areas
              - Local and temporary inefficiencies
              - Light damage without inefficiency
Impact of natural disasters on development:
Disasters severely impact the development of a region. All the funds and manpower are diverted to mitigate the efforts of a disaster. The  entire socio-economic activity comes to a grinding halt. A lot of time, money and manpower is used-up in response, reconstruction and rehabilitation work. The government is forced to put all work on the back burner and bring the disaster in focus till the effects of the disaster are minimized and life limps back to normal.


Population explosion refers to growth of a population at exponential rates to a size that exceeds the environmental carrying capacity of a region. It is usually followed by a population crash.
-A population can be defined as a group of individuals of the same species inhabiting an area
-Population density is the population size in relation to some unit of space and time. It varies with food availability and climatic conditions
-Current population growth has led to famine in areas where food production cannot keep pace with population growth
-The kinds of demands a population places on its resources is also important
-Each species has an inherent reproductive capacity
-Population growth tends to follow a particular pattern. This consists of a lag phase, an exponential growth phase and a stable equilibrium phase.
-When a majority of the population is in the reproducing stage, the population begins to increase at an exponential rate and this stage is called exponential growth phase.This leads to population explosion.
-The graph plotted between population on Y-axis and time on X-axis yields an S shaped growth or a J shaped growth curve showing the growth rate pattern
-Human beings have accumulated knowledge that allows for predictions about the future and can make conscious decisions based on likely course of events and adjust their lives accordingly.

Man has modified the environment with new technologies for a better and secured future on me hand and created the problem of population explosion on the other hand. Some of the factors controlling population growth are listed below:
-Famine and other natural calamities like flood, drought, earthquake, volcanic eruptions, hurricanes, landslides, etc
-Epidemic outbreaks (Ebola virus, etc)
-Unnatural accidents caused during transportation, fires, etc

-High production of food and better technologies for storage, processing and distribution
-Better medical facilities provided during childbirth and immunization for babies against deadly diseases

The population of a given area also depends on the movement of people either temporarily or permanently.
Emigration refers to movement of people from one community to another in a new locality thus causing a decrease in the original population
Immigration refers to addition of new individuals to a population from other localities
Increase in population causes competition due to identical requirements.
One of the most important consequences of increase in population is scarcity of food leading to starvation and death in extreme cases.
Interaction between populations in a given area can lead to conflicts due to competition for resources or dependence of one on the other (Symbiosis - birds eat ticks on the skin of cows & buffaloes)

The following are the consequences of population explosion:
-Depletion of resources
-Competition for food and space
-Psychologocal stress
-Pollution of the environment
-Large scale unemployment


The management of a single unit of land with its water drainage system is called watershed management. It is a technique that has several components. The main components of watershed management are:
-Soil and water management and
-Development of vegetative cover
Natural drainage of a watershed unit if managed properly brings about:
-local prosperity due to abundance of water throughout the year
-Abundant water improves the quality of human life in the area by improving health in the community
-Watershed management enhances the growth of agricultural crops and makes it possible to grow more than one crop in a year in dry areas.
-Watershed management begins by taking control over a degraded site by local participation.
-The first step involves taking appropriate soil conservation measures. This is done by constructing a series of long trenches and mounds along hills to hold the rainwater and allow it to percolate in the ground. This ensures that underground stores of water are completely recharged.
-By growing plants, shrubs and trees, soil erosion due to monsoon can be minimized.
-By stall feeding, local grass cover can be increased as free grazing by domestic animals is prevented.
-'Nala' plugs are made in streams so that water is held in streams and does not rush down the hill side.
-Check dams are built in selected sites that hold back large amounts of water.
All the above listed steps constitute watershed management.
Watershed management improves water-table and keeps streams and nalas flowing throughout the year.
-Deforestation is one of the major causes for degraded areas. Afforestation of such degraded areas is an important aspect of watershed management. 


-The Air act provides for establishment of central and state boards for implementation of rules under the act
-The Air act aims at prevention, control and abatement of air pollution
-pollution beyond certain limits due to various pollutants discharged through industrial emission is monitored by pollution control boards set up in every state
-The Central Pollution Control Board (CPCB) implements legislation to improve quality of air, prevent and control air pollution in the country.
-The board advises the central government on matters concerning quality of air. It also coordinates activities, provides technical assistance and guidance to state boards in addition to setting the standards for quality of air.
-It collects and disseminates information in respect to air pollution and performs functions prescribed by the act.
-The state boards advise the state government on matters concerning prevention and control of air pollution
-The state boards possess the right to inspect at all reasonable times any control equipment, industrial plant or manufacturing process and give orders to take necessary steps to control pollution.
-The state board inspects air pollution control areas at regular intervals or whenever necessary.
-They are empowered to provide standards for emissions to be laid down for different industrial plants with regard to quantity and composition of emissions.
-A state board may recognize or establish a laboratory for this purpose.
-State government has powers to declare air pollution control areas after consulting with state boards. In the same manner, state government can give instructions to ensure standards of emission from automobiles and restrict operation of certain industrial units.
-Penalties are imposed by the state board and it might appeal to the court to restrain persons for causing air pollution.
-Any person who contravenes any provision of the act is punishable with imprisonment for a term extending to three months or a fine of Rs.10,000 or both. If the offence continues, an additional fine may extend to Rs. 5000 per day for everyday during which the contravention continues after conviction for the first contravention.

Water act came into effect in 1974 to prevent pollution of water by industrial, agricultural and household water. The main objectives of this act are listed below:
-Prevention, control and abatement of water pollution.
-The act also aims at restoration of wholesomeness of water
-The water act is designed to assess pollution levels and punish polluters
-The central government and state governments have set-up pollution control boards to monitor water pollution.
-The water act of 1974 along with amendments in 1978 is an extensive legislation with more than sixty sections for prevention and control of water pollution.
-Central and state boards have been created under this act for preventing water pollution
-The act empowers the board to take:
               -  water samples for analysis
               - govern discharge of sewage
               - trade effluents
               - study or inspect appeals
               - revision of policies
               - set minimum and maximum penalties
               - publication of names of offenders
               - offences by companies or government departments
               - establish or recognize water testing laboratories and standard testing procedures
-Prevention and control of water pollution is achieved through a 'permit' or a 'consent administration' procedure
-Discharging effluents is permitted by obtaining the consent of state water boards
The objective of this act is that anyone consuming water has to pay cess depending on the type of use as listed below:
-Industries using water for industrial cooling, spraying in mine pits or as boiler feed
-Domestic purposes
-Processing (pollutants are biodegradable. Eg: water from slaughter houses)
-Processing (pollutants are not biodegradable and are toxic. Eg: water from tannery waste, industrial wastewater from electroplating industries)
Industries that have a treatment plant installed for treating their effluents can get a rebate of 70% on the cess payable.

The wildlife act is aimed at preserving and protecting wildlife and came into effect in 1972.
-This act envisages national parks and wildlife sanctuaries as protected areas to conserve wildlife.
-Under this act, wildlife populations are regularly monitored and management strategies are formulated to protect them.
-The act covers the rights of forest dwellers. The act permits restricted grazing in sanctuaries but prohibits the same in national parks. The act also prohibits collection of non forest timber which might not ham the system.
-The rights of forest dwellers recognized by forest policy of 1988 were taken away by the amended wildlife act of 1991
-The act enables central government to enact the legislation.
-The act appoints a wildlife advisory board, wildlife warden and specifies their duties and powers.
-The act provides a comprehensive list of endangered species and prohibits hunting of the same.
-It protects endangered plants like Beddome Cycad, Blue Vandana, Ladies Sliper Orchid, Pitcher Plant, etc
-The act provides for setting up national parks, wildlife sanctuaries, etc.
-The act provides for constitution of central zoo authority
-There is provision for trade and commerce in some wild species with license for sale, purchase, transfer, etc
-The act imposes a ban on trade or commerce of commercial animals
-The act provides legal powers to officers to punish offenders.
-Under the act, captive breeding programs for endangered species have been initiated.
Eg: Conservation project for Lion (1972), Tiger (1974), Crocodile (1974) & Brown antlered deer (1981)


Noise pollution is defined as unwanted or offensive sound that unreasonably intrudes into daily activities. Noise pollution is a problem that affects human health and contributes to a general deterioration of environmental quality.
Sound is measured in decibels (dB)
As per environment protection rules 1999, the permitted noise level is 125 dB.

SOURCES Sources are broadly classified into:
Outdoor  sources: Ex - Industries, Vehicular movement, Construction work, Defence equipment, Explosion, Loud speakers during festivals, high speed aircrafts, launching of Satellites using rockets, etc
Indoor sources: Playing radio or music loudly

EFFECTS: The effects due to excess noise pollution are listed below:
-Emotional or psychological effects such as irritability, anxiety, stress, lack of concentration and mental fatigue
-It has been observed that the performance of school children is poor in comprehension tasks when schools are situated in busy areas of a city due to high background noise.
-Noise interferes with normal auditory communication and may mask auditory warning signals increasing the rate of accidents especially in industries.
-Severe noise pollution may be extremely annoying or painful and hazardous. It lowers workers efficiency at work leading to low productivity and is the main reason for high accident rates on the job.
-Physical damage to the ear and temporary hearing loss called Temporary Threshold Shift (TTS) is experienced. In this case, people will be unable to detect weak sounds. However, hearing ability is regained within one month. Permanent hearing loss called Noise Induced Permanent Threshold Shift (NITPS) is a type of hearing loss from which there is no recovery

At sound level:
less than 80dB - no hearing loss occurs
80 to 130 dB   - temporary effects
more than 95 dB - approximately 50% people develop NIPTS
more than 105 dB - most people experience permanent hearing loss
more than 150 dB - physically ruptures human ear drum
more than 180 dB - kills a person

-Noise pollution may also cause harmful effect on circulatory system by raising blood pressure and altering pulse rates.

The four major concepts to control noise pollution are listed below followed by a brief explanation.
-Reduce noise at source
-Block path of noise
-Increase path length
-Protect recipient
Reduction of noise at source: This can be accomplished by:
-muffling vehicles and machinery to reduce noise
-using rigid sealed enclosures around machinery lined with acoustic absorbing material
-Isolating machines and their enclosures from the floor by using special spring mounts or absorbing mounts and pads
-Regular and thorough maintenance of operating machinery
-Regular lubrication and correct installation of bearings
-Proper highway planning and design are essential for controlling traffic noise.
Blocking path of noise: This can be accomplished by:
-Planting of trees around houses as they act as effective noise barriers
-Using highly absorptive interior finish material for walls, ceilings and floors decreases indoor noise levels
Increasing path length:
-Municipal land use ordinances pertaining to the location of airports make use of the attenuating effect of distance on sound levels
Protect the recipient:
-Specially designed ear plugs and ear muffs reduce the sound level reaching the ear drum by almost 40 dB
-Education, awareness among people and legislation regarding noise pollution should be widely publiced for control of noise pollution.
Eg: Ban on loud speakers from 10 pm to 6 am.


Soil is the thin covering over land that consists of a mixture of a mixture of minerals, organic material, living organisms, air and water that support life. The several factors that contribute to formation of soil from parent material are listed below:
-mechanical weathering of rocks due to temperature changes and abrasion
-wind, moving water, glaciers, chemical weathering activities and lichens
-Climate and time are important factors that contribute significantly in the development of soil.
          Extremely cold or dry climate result in slow development of soil
          Humid or warm climates result in rapid formation of soil

Soils are arranged in a series of zones called SOIL HORIZONS
Each horizon has a distinct texture and composition and this varies with different types of soils.
Cross sectional view of horizons in a soil is called SOIL PROFILE
Top layer (surface litter layer) called the 'O' horizon is composed of freshly fallen and partially decomposed leaves, twigs, animal waste, fungi and other organic matter. It is brown or black in colour.
Uppermost layer of soil is called 'A' horizon and it consists of partially decomposed organic matter (humus) and some inorganic mineral particles. It is darker and looser than deeper layers.
Roots of most plants are found in these two upper layers mentioned above.
When these layers are anchored by roots of vegetation, soil stores water and releases it slowly as a trickle.
These layers contain a large amount of bacteria, fungi, earthworms and other small insects that form complex food webs in soil and help recycle soil nutrients thereby contributing to soil fertility.

The 'B' horizon also called subsoil contains less organic material and fewer organisms than 'A' horizon

The area below the subsoil is called'C' horizon and is made-up of weathered parent material. This layer does not contain any organic matter and helps determine the pH of soil. It affects the soiil's rate of water absorption and retention

Soils vary in their content of clay, silt, sand, and gravel. Soils with approximately equal mixtures of clay, silt, sand and humus are called LOAMS.


EROSION: Erosion is defined as movement of surface litter and top soil from one place to another.
-It is a natural process caused by wind and flowing water
-It is accelerated by human activities like farming, construction, overgrazing by livestock, burning of grasses and deforestation
-It reduces fertility of soil and water holding capacity
-It contributes to water pollution
-It clogs lakes
-It increases turbidity of water
-It leads to loss of aquatic life
-If top soil erodes faster that it is formed, the soil becomes a non-renewable resource
-Water and soil are conserved by integrated treatment methods
-The types of treatment are:
-Area treatment and
-Drainage line treatment

EXCESSIVE USE OF FERTILIZERS: The use of chemical fertilizers has increased substantially over the past few decades.
-Fertilizers are valuable as they replace the nutrients used-up by plants
-Primary soil nutrients in short supply are Potassium (K), Phosphorus (P) and Nitrogen (N). They are also called macronutrients
-Boron (B), Zinc (Zn) and Manganese (Mn) are required in small amounts and are called micronutrients.
-When crops are harvested, large amounts of macronutrients and small amounts of micronutrients are removed with crops.
-On growing the same crops again, low amount of nutrients results in decreased yield
-Necessary nutrients are returned to soil by the application of fertilizers.

-Along with fertilizers, pesticides, herbicides, weedicides and fungicides are used to kill unwanted insects, plants and fungi. Rats and mice are killed by rodenticides and plant pests are killed using herbicides.
-Pesticides kill not only pests but also human beings (in sufficiently high doses)
-Persistent pesticides applied once are effective for a long time. They accumulate in the soil and in the bodies of animals in the food chain.
-Biomagnification of persistent pesticides (DDT - half-life = 10 to 15 years)
-Development of insect resistance to insecticides causes farmers to use higher concentration of the same pesticide or use of a different pesticide of higher toxicity
-Pesticides kill beneficial (natural predtors and pollinators) organisms as well as pest species
-Exposure to small quantities of pesticides over several years can cause mutations, cancers, etc.

Alternative agriculture is the broadest term used to describe all non-traditional agricultural methods. This includes:
-sustainable agriculture
-organic agriculture
-alternative methods raising crops
-alternative uses of traditional crops, etc

Irrigated lands produce crop yields much higher than those that use only rain water. Irrigation water contains dissolved salts and in dry climates, the water in the salt solution evaporates leaving salts (NaCl, MgCl2, Na2CO3, etc) in the top soil. The accumulation of salts in soil is called salinization. This leads to:
-stunted plant growth
-low yields
-eventually kill the crop.
Thus, salinization renders the land useless for agriculture.
Salts can be flushed out of soil by using more water. However, this wastes large amounts of water and increases salinity of irrigation water downstream.
If large amounts of water are used to leech salts deep into the soil and drainage is poor, water accumulates underground and gradually raises the water-table covering the roots of plants. This causes the plants to die.

Soil pollution is defined as the introduction of substances, biological organisms or energy into the soil resulting in a change in the quality of soil affecting the normal use of soil or endangering public health and the living environment.

-Accidents involving vehicles transporting waste from site of origin to site of disposal
-Accidents involving vehicles carrying fuel that contaminate the soil when spilled.
-Pollutant might be washed away by precipitation or evaporate if volatile.

Soil pollution is caused by the presence of man-made chemicals or other alteration in the natural soil environment. This type of contamination typically arises from the rupture of underground storage links, application of pesticides, percolation of contaminated surface water to subsurface strata, oil and fuel dumping, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals. This occurrence of this phenomenon is correlated with the degree of industrialization and intensities of chemical usage.

A soil pollutant is any factor which deteriorates the quality, texture and mineral content of the soil or which disturbs the biological balance of the organisms in the soil. Pollution in soil has adverse effect on plant growth.

Since the metals are not degradable, their accumulation in the soil above their toxic levels due to excessive use of phosphate fertilizers, becomes an indestructible poison for crops.

-Food shortage: Soil pollution leads to water pollution and reduced food production leading to food shortage. This problem is aggravated by population growth.
-Desertification: Continuous exposure of eroded soil to sun for longer periods transforms land into sandy and rocky land. These are symptoms of desertification and render the soil unsuitable for cultivation
-Decrease in extent of agricultural land
-Top soil that is washed away contributes to water pollution by clogging of lakes and increasing turbidity of water leading to loss of aquatic life.
-Fertilizer run-off leads to eutrophication of waterways.

-Proper conservation measures to minimize loss of top soil
-Using Integrated Nutrient Management (INM) and Integrated Pest Management (IPM), bio-pesticides and integrated environment friendly agriculture to reduce dependence on synthetic fertilizers and pesticides.
-Appropriate water management practices in agriculture.
-Keeping soil surface covered with crop residues or crop cover
-Planting trees as part of afforestation
-Using trees as wind breakers or shelter belts
-Undertaking clean-up operations on polluted soils.

Wednesday, October 29, 2014

Environmental Studies - Biodiversity, Environmental Pollution and Legislation along with miscellaneous topics

A plant, animal or microorganism that is in immediate risk of biological extinction is called endangered or threatened species.
The following are the threats to biodiversity:-
-Habitat destruction (Draining and filling-up of inland wetlands)
-Extension of agriculture
-Filling-up of wetlands
-Conversion of rich biodiversity site for human settlement and industrial development
-Destruction of coastal areas
-Uncontrolled commercial exploitation
-Pollution (Frog eggs, Tadpoles and adults are extremely sensitive to pollutants especially pesticides)
-Populations can be adversely affected by introduction of non-native predators and competitors
-Disease producing organisms play an important adversary in reducing populations of endemic species.
Asia's rarest animals found in India are:
-Asiatic Cheetah
-Asiatic Lion
-Asiatic Wild Ass
-Bengal Fox
-Indian Elephant
-Indian Rhinocerous
-Marbled Cat
Endemic species are species concentrated in a particular region. 60% of the endemic species are found in the himalayas and western ghats in India.
-NE India
-NW Himalayas
-Western Ghats and
Andaman & Nicobar islands
Endemic flora found in India are:
-Sapria Himalayana
-Ovaria Lurida
-Nepenthis Khasiana
Endemic species of conservation significance in the western ghats are:
-Lion Tailed Macaque
-Nilgiri Langur
-Brown palm civet and
-Nilgiri Tahr
187 endemic reptiles and 110 endemic amphibian species are found in India.
IUCN (International Union for Conservation of Nature and natural resources) defines conservation as management of human use of biosphere so that it might yield the greatest sustainable benefit while maintaining its potential to meet the needs and aspirations of future generations.
Biodiversity is one of the important tools for sustainable development. The commercial, medical, genetic, aesthetic and ecological importance of biodiversity emphasizes the need for its conservation.
-provides recreation and tourism
-preserves genetic diversity of plants and animals
-ensures sustainable utilization of life supporting systems on earth
-is essential for conservation of ecological diversity and life supporting systems
-helps maintain a stable and healthy environment
-is an important source for drugs, herbs, food and other important raw material as these are derived from plants and animals
Types of biodiversity conservation
1. In-situ conservation and
2. Ex-situ conservation
In-situ conservation involves protection of flora and fauna within its natural habitat. These areas are called protected areas. It is the ultimate conservation strategy.
Ex: National parks, Gene Sanctuaries, wildlife Sanctuaries and Biosphere reserves
Biosphere reserves:-cover large areas (>5000 sq. km)
-are used to protect species for a long time
Role of biosphere reserves are:
-long time survival of evolving ecosystem
-protection of endangered species
-protect maximum number of species and communities
-serve as site of recreation and tourism
-used for educational and research purposes
Biosphere reserves serve as an open system and changes in land use are not allowed. Explosive activities are not allowed in biosphere reserves.
A national park is an area dedicated for the conservation of wildlife along with its environment. It covers an area ranging from 100 to 500 sq km. One or more national parks may exist within a biosphere reserve.
A national park is used for enjoyment through tourism without affecting the environment. It is used to protect, propogate and develop wildlife.
Grazing domestic animals inside national parks is prohibited. All private rights and forestry activities are prohibited inside a national park.
Wildlife sanctuary is an area that is reserved for conservation of animals only. It allows operations such as harvesting of timber, collection of forest products, private ownership rights and forest operations provided it does not affect animals adversely.
Gene sanctuary is an area where plants are conserved.
Few notable projects for the conservation of animals are listed below:
-Project Tiger
-Gir Lion Project
-Crocodile breeding project
-Project Elephant, etc
The advantages of this type of conservation are listed below:
-It is cheap and convenient
-Species get adjusted to natural disasters like flood, drought, forest fires, etc
The disadvantages of this type of conservation are listed below:
-large surface area of earth is required to preserve biodiversity
-Inadequate maintenance due to shortage of staff and pollution
Ex-situ conservation refers to conservation of flora and fauna outside their natural habitat.This type of conservation is mainly done for conservation of crop varieties and wild relatives of crops. It provides back-up solution to in-situ conservation projects.
Ex-situ conservation involves maintenance and breeding of endangered plant and animal species under controlled conditions
It identifies those species that are at high risk of extinction
It prefers species that are important for man in near future among the endangered species.
Ex: Seed banks, botanical gardens, microbial culture collections, cell cultures, pollen storage, tissue culture, genetic engineering centres and zoological gardens.
Methods of Ex-situ conservation
-National Bureau of Plant Genetic Resources (NPBGR)
 It is located in New Delhi
 It uses CRYOPRESERVATION technique to preserve agricultural and horticultural crops
 This technique involves using liquid nitrogen at -19 C
 Varieties of rice, turnip, radish, tomato, onion, carrot, chilli, tobacco, etc have been successfully preserved for years using this technique.
-National Bureau of Animal Genetic Resources (NBAGR)
 It is located in Karnal, Haryana
 It preserves the semen of bovine domesticated animals
-National Facility for Plant Tissue Culture Repository (NFPTCR)
 It conserves varieties of crop plants or trees using tissue culture
 This facility has been created within the NBPGR.

Benefits of biodiversity conservation:
1. Increase in food supplies by developing new crop plants, animal sources, etc
2. Increased use of biological control agents to control pests
3. Source of genes through hybridization and genetic engineering

Threats to biodiversity:
Human population growth, industrialization and change in land-use pattern (Ex: Urban sprawl)
Man-wildlife conflicts
Habitat loss
The reasons for loss of biodiversity are listed below:
-Destruction of forests
-Over-exploitation of bio-resources
-Shifting cultivation
-Illegal trade
-Smuggling and biopiracy
-Soil degradation and erosion
-Diminishing green cover
-Mining for ores
-Infrastructure development (Roads, river valley projects)
-Exploitation of timber and non-timber forest produce
-Loss of land fertility
-Tourism business
-Greed vs Need

Issues involved in enforcement of environmental legislation
Environmental legislation has minimal impact on the social fabric and people in a community without effective enforcement. Environmental legislation evolved to protect the human population, the environment and the earth's resources. Successful implementation of environmental legislation involves data collection and analysis. This information is then passed on to an enforcement agency that takes necessary legal action on all defaulters. The issues essential for enforcement of environmental legislation are:
-Precautionary principle: This principle evolved to deal with risks and uncertainities faced by environmental management. It does not prevent problems but mau reduce their occurrence and ensures preparation of contingency plans.
-Polluter pays principle: This principle states that a polluter pays for damaging the environment in addition to monitoring and policing. There is a debate if this principle should be retrospective.
Freedom of Information: Environmental planning and management is hindered if anyone is not given access to information. Under this principle, every citizen of the country, or any organization, Ex: NGO is provided access to information on the environment due to infrastructure development projects.

Monday, September 15, 2014

Natural resources: Water resources

Water resources
Almost 71% of earth's surface is covered by water of which 97% is ocean waterwhich is unusable due to high salt concentration. Almost 2.6% of fresh water is  is trapped in ice caps and glaciers along with some part stored underground. Only 0.4% of the total quantity of water is available in swamps, rivers, lakes and streams.

Surface water sources
Sea water
River and streams
Natural lakes and ponds
Artificial impounding reservoirs

Ground water sources
After glaciers, ice caps and snow fields, ground water is the next largest fresh water reservoir. Precipitation that does not run-off over the surface, percolates through the soil and either accumulates in an underground basin or flows underground in sub surface streams.

Effects of over-utilizing ground water
-Excessive pumping of ground water causes porous formations to collapse resulting in subsidence
-Heavy pumping can lower water table and cause shallow wells to dry-up or even deplete the entire aquifer.
-Over-use of freshwater reservoirs along coast lines often allows salt water to intrude into aquifers rendering the water unfit for domestic, industrial or agricultural purposes.

Ecological pyramids

Ecological Pyramid
Ecological pyramids are of three types:
i. Pyramid of numbers
ii. Pyramid of energy
iii. Pyramid of biomass
The concept of ecological pyramid was developed by Charles Elton; these pyramids are also known as Eltonian pyramids. The pyramids are a graphical representation which depicts the number of organisms, biomass and productivity at each trophic level. All ecological pyramids begin at the bottom with the produces and proceed through different trophic levels. 

Ecological pyramids begin with the producers at the bottom like plants and they proceed to various trophic levels like herbivores consume plants, carnivores prey on herbivores and so on. The highest level is at the top of the food chain.  

Ecological Pyramid

Consider a grassland ecosystem for example:
In a grassland ecosystem, the producer is grass which is small in size but large in number. Hence, it
occupies the lowest trophic level (I trophic level).
The primary consumers are rats (herbivores) and they are more in number than grass. Therefore they
occupy the second trophic level (II trophic level)
The secondary consumers are snakes (carnivores) and they are fewer in number than the rats. They
occupy the third trophic level(III trophic level)
Eagles are the tertiary consumers that feed on snakes and they are at the top of the pyramid with the
least in number. They form the apex in the pyramid of numbers. The diagram is shown above which is self-explanatory.
The pyramid of energy or the energy pyramid describes the overall nature of the ecosystem. During the flow of energy from organism to other, there is considerable loss of energy in the form of heat. The primary producers like the autotrophs there is more amount of energy available. The least energy is available in the tertiary consumers. Thus, shorter food chain has more amount of energy available even at the highest trophic level. 
  • The energy pyramid always upright and vertical. 
  • This pyramid shows the flow of energy at different trophic levels. 
  • It depicts the energy is minimum as the highest trophic level and is maximum at the lowest trophic level. 
  • At each trophic level, there is successive loss of energy in the form of heat and respiration, etc. 
Pyramid of Energy
The pyramid of numbers depicts the relationship in terms of the number of producers, herbivores and the carnivores at their successive trophic levels. There is a decrease in the number of individuals from the lower to the higher trophic levels. The number pyramid varies from ecosystem to ecosystem. There are three of pyramid of numbers:
  • Upright pyramid of number 
  • Partly upright pyramid of number and
  • Inverted pyramid of number.
Upright Pyramid of Number 
This type of pyramid number is found in the aquatic and grassland ecosystem, in these ecosystems there are numerous small autotrophs which support lesser herbivores which in turn support smaller number of carnivores and hence this pyramid is upright.

Pyramid of Number
Partly Upright pyramid of Number 
It is seen in the forest ecosystem where the number of producers are lesser in number and support a greater number of herbivores and which in turn support a fewer number of carnivores.

Partly Upright Pyramid of Number
Inverted Pyramid of Number 
This type of ecological pyramid is seen in parasitic food chain where one primary producer supports numerous parasites which support more hyperparasites.

Inverted Pyramid of Number
The pyramid of biomass is more fundamental, they represent the quantitative relationships of the standing crops. In this pyramid there is a gradual decrease in the biomass from the producers to the higher trophic levels. The biomass here the net organisms collected from each feeding level and are then dried and weighed. This dry weight is the biomass and it represents the amount of energy available in the form of organic matter of the organisms. In this pyramid the net dry weight is plotted to that of the producers, herbivores, carnivores, etc. 

There are two types of pyramid of biomass, they are:
  • Upright pyramid of biomass and 
  • Inverted pyramid of biomass. 
Upright Pyramid of Biomass
This occurs when the larger net biomass of producers support a smaller weight of consumers.
Example: Forest ecosystem.

Biomass Upright Pyramid in Terrestrial Ecosystem

Inverted Pyramid of Biomass
This happens when the smaller weight of producers support consumers of larger weight.
Example: Aquatic ecosystem.

Inverted Pyramid of Biomass in Aquatic Ecosystem

Energy flow in an ecosystem

Energy flow in an ecosystem
The manner in which energy flows in an ecosystem is known as energy flow. It is unidirectional. The
following points are important with regard to understanding energy flow in an ecosystem:
i. Efficiency of producers in absorption and conversion of solar energy.
ii. Using the converted energy (chemical energy – starch) by consumers
iii. Total input of energy as food and its efficiency of assimilation
iv. Energy lost through respiration, heat, excretion, etc at each trophic level
v. Gross production and net production

Two important points to be noted about energy flow in ecosystems are:
i. Energy flow is unidirectional and
ii. There is a progressive decrease of energy as we progress along the food chain. The
energy is lost as heat in metabolic activities such as respiration, hunting, etc.

Structure and Function of an Ecosystem

Structure and function of an ecosystem
The two important aspects of an ecosystem are:
  • Structure and
  • Function

Structure of an ecosystem consists of
  • Composition of biological community (eg: plants, animals and microbes), biomass, life cycles and distribution in space.
  • Quantity, distribution and cycling of non-living materials (macro and micro nutrients, trace elements and water)
  • Variation of conditions like temperature, rainfall, sunlight, relative humidity, wind and topography.
Function of an ecosystem consists of
  • Rate of biological energy flow (production and respiration rates)
  • Rate of nutrient cycles
  • Ecological regulation (Environment regulation in the form of photoperiodism and Organism regulation in the form of nitrogen fixation by organisms)

From the trophic stand-point, an ecosystem has two components
  • Autotrophic component and
  • Heterotrophic component

Autotrophic component involves
  • Fixation of light energy
  • Use of simple inorganic substances like carbon and water
  • Synthesis of hexose sugars (glucose) to complex substances such as polysaccharide carbohydrate (starch), fat and protein synthesis.

Heterotrophic component involves
  • Utilization
  • Rearrangement and Decomposition of complex substances
  • Herbivores, Carnivores and Omnivores (Phagotrophs) and microconsumers (decomposers, osmotrophs and saprotrophs) comprise the heterotrophic component.

Food chains Vs Food webs

GRASS manufactures its food using SUNLIGHT, WATER, NUTRIENTS from soil and CHLOROPHYLL
The GRASS is eaten by a GRASSHOPPER
The GRASSHOPPER is eaten by a FROG
The FROG is eaten by a SNAKE
The SNAKE is eaten by a HAWK.

TREES produce ACORNS which act as food for many MICE and INSECTS.
Because there are many MICE, WEASELS and SNAKES have food.
The insects and the acorns also attract BIRDS, SKUNKS, and OPOSSUMS.
With the SKUNKS, OPPOSUMS, WEASELS and MICE around, HAWKS, FOXES, and OWLS can find food.
They are all connected! Like a spiders web, hence it is called a FOOD WEB.

In a food chain, any disturbance in the food supply affects the entire food chain. However in the food web, any disturbance in the food supply is compensated by other organisms available as food at the same trophic level.

Food webs are far more complex than the simple food chain

Several interconnected food chains form a food web.

The real world we find food webs everywhere. Food chain is only a simplistic view of the complex real world phenomena.

Wednesday, September 10, 2014

Agriculture - Effects of modern methods and options

The widespread use of chemicals in agriculture as fertilizers, pesticides, insecticides and rodenticides without proper technological information have multiplied the hazards to which human beings are exposed. These chemicals spread through the environment and pose a threat to all animals.
Fertilizers are materials that are added to soil to restore and enhance soil fertility to improve the quality and quantity of plant growth.
Fertilizers may be natural or artificial (synthetic). Natural fertilizers are further divided into Organic and inorganic fertilizers. Examples of inorganic fertilizers are Gypsum, Crushed limestone and sulphur rock phosphate while those for organic fertilizers are manure, animal excreta, plant wastes and humus.
Excess fertilizers that are not taken-up by plants, leech into sub-soil water sources and contaminate them. They are non-biodegradable and thus accumulate to reach objectionable levels as they pass through different levels of the food chain.
The main problem with fertilizer use is the contamination of water with nitrates, phosphates and potassium.
Nutrients are lost from agricultural fields through:
-Drainage and
-Attachment to eroded soil particles
Amount of nutrient lost depends on:
-Soil type and organic matter content
-Depth to groundwater and
-Amount and type of fertilizer and irrigation used
The major nutrients in fertilizers are:
-Nitrogen (N)
-Phosphorus (P) and
-Potassium (K)
Nitrogen is readily lost due to high solubility in nitrate form. Leaching of nitrate from agricultural fields can increase groundwater concentrations to unacceptable levels for drinking water supply
High nitrate levels in drinking water are dangerous to human health
Phosphorus cannot be washed out of soil but can be washed into surface waters together with the soil that is being eroded.
Phosphorus is not dangerous. However, it stimulates the excess growth of algae and this process is called "eutrophication". The algae eventually die and decompose resulting in depletion of dissolved oxygen thereby killing fish.
Potassium does not cause water quality problems. Its solubility is similar to phosphorus i.e., it is similarly bound by soil particles and can be by erosion.
Qualities of an ideal pesticide:
-It should only kill target pest
-Have no short term or long term effects on non-target organisms
-Should be able to be broken down into harmless compounds in a short time
-Should prevent the development of genetic resistance in target organism
-Save money compared to making no effort to control pest
Since 1945, different types of synthetic organic chemicals have been used as pesticides.
Worldwide, 2.3 million Tonnes of pesticides are used (85% in developing countries.
Synthetic nsecticides are of the following types:
Chlorinated hydrocarbons

DDT and other slowly degradable chlorinated hydrocarbon insecticides were banned in mid 1970s
Organophosphates are more rapidly biodegradable but are water soluble and could possibly contaminate surface and groundwater sources.
Chlorinated hydrocarbons are fat soluble
Farmers apply non-persistent pesticides at regular intervals to ensure effective insect control. The regular use of using non-persistent pesticides is almost as good as using persistent pesticides.
Pyrethrin (from wild chrysanthemum type plants) and Rotenoids (from roots of rain forest legumes) are produced from wild plants and can be effectively used as biological control agents as they are:
-Effective in low doses and
-Cause little harm to mammals
The following are the benefits of using pesticides:
-pesticides save lives
-they increase food supplies and lower food costs
-they increase profits of farmers
-they work faster and better than alternatives
-safer and more effective products are continuously being developed.
Development of genetic resistance
Modifying cultivation process
-crop rotation
-planting rows of hedges or trees in and around crop fields
-adjusting planting times
-destroy diseased or infected plants
-growing crops in areas where their major pests do not exist
-using plant diversity to control pests by adopting:
                         agro-forestry and
-artificial selection, cross breeding and genetic engineering varieties of plants and animals that are genetically resistant to certain pest insets, fungi and diseases.
-biological pest control against various natural parasites and pathogens can be introduced to control the populations of specific pests.
Organic agriculture is defined as an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony.

Agriculture has been a practice in use for hundreds of years. It provides countless people with sustenance and livelihood all over the world. However, modern practices in agriculture have led to several damaging effects on the environment listed below:
1.Agriculture increases carbon dioxide levels making it one of the main sources of carbon dioxide emissions for decades. This in-turn aggravates the problem of global warming and consequent sea level rise.
2.Animal waste from farms contains harmful pathogens known to cause disease and infection. By getting into soil and water systems they create irreversible damage to land and pose health risks towards humans. These problems lead both directly and indirectly to these health risks, and may causes disorders such as hepatitis and meningitis.
3.Fertilizers also put forth several complications. They contain harmful elements such as nitrogen and phosphates, both of which negatively affect air and water quality. Its use causes the release of ammonia, nitrogen runoff and eutrophication, all of which have negative effects on the environment.
4.Impacts also include increased water or wind erosion, depleted groundwater supplies in irrigated areas,
5.Modern agriculture converts an ever-increasing portion of the earth's land surface to monoculture. As a result, the genetic and ecological diversity of the planet erodes. The conversion of diverse natural ecosystems to new agricultural lands and the narrowing of the genetic diversity of crops contribute to this erosion.
6.In addition to adding pollutants to water, soil and air, modern agriculture practices can cause soil disturbance by using heavy machines and tilling equipment. This, in turn, creates soil erosion and degrades the quality of surrounding farmland.
7.A number of "ecological diseases" have been associated with the intensification of food production. They may be grouped into two categories: diseases of the ecotope, which include erosion, loss of soil fertility, depletion of nutrient reserves, salinization and alkalinization, pollution of water systems, loss of fertile croplands to urban development, and diseases of the biocoenosis, which include loss of crop, wild plant, and animal genetic resources, elimination of natural enemies, pest resurgence and genetic resistance to pesticides, chemical contamination, and destruction of natural control mechanisms.

Tuesday, September 9, 2014

Natural resources - Land resources


Human and natural activities need space for their location and development. This space is provided by land which is put to various uses like food and energy production, waste-disposal, industrial, commercial and residential purposes.

Land houses the living species, water resources and raw material resources (minerals and ores).
Pattern of land use on earth is:
Arable land
Land for pastures and meadows
Forest land
Urban land and
Non-agricultural land

Land-use involves economic activities leading to environmental problems like:
Pollutant discharge
Waste disposal
Consumption of natural resources for economic activity
Disturbing ecological cycles and wildlife habitats

Changes within a particular land-use category result in major changes in landscape thereby reducing its capacity support a diversified and balanced wildlife. This reduces tourist and recreational value. Ultimately this results in reduced potential for multiple use of these areas. Land being used for one purpose may be used for another purpose. The following examples are listed:
Agricultural land might be used as an urban area
Agricultural land may be used for forestry
Forest land may be cleared for agricultural purposes

Significant negative effects are seen on the environmental quality as a result of the above listed land use changes:
Impact on water cycle
Impact on ground and surface water
Emission of water pollutants
Emission of air pollutants
Destruction of wildlife due to habitat destruction
Degradation of soil

List of environmental conflicts between adjacent land owners
Residential areas located near industrial areas are affected due to air pollution due to effluents due to effluents of energy and industrial effluents.

Residential areas located near airports and along highways and motorways suffer from nuisance due to air pollution

Intensive live-stock breeding units are a source of offensive odours to nearby dwellers

Development of linear infrastructure (roads and railway tracks) in rural areas affects existing land-use as well as natural ecosystems (forests, etc)

The surface layer of land is called soil. 
Fertility or productive capacity of the soil depends on the minerals it contains. 
Minerals are mainly available to the top layer of the soil. Hence, the top layer is the best for vegetation.

Land degradation refers to deforestation or deterioration or loss of fertility or productive capacity of soil. The factors contributing to land degradation are listed below and discussed subsequently.

Soil erosion
Soil pollution
Salination and water logging
Shifting cultivation

Soil erosion is the loss or removal of the superficial layer of soil by the action of water, wind or human activities. Factors influencing the extent of soil erosion are:
Distribution, intensity and amount of rainfall:
Unequal distribution of rainfall results in heavy rainfall being restricted to a few months. The soil unable to absorb this heavy rainfall causes run-off water that removes layers of soil as it moves, resulting in soil erosion.
Slope of the ground: Steep slopes cause decreased infiltration and increased run-off resulting in more soil erosion.
Nature of the soil: Light, open soils lose more silt than heavier soils (loam) that swell-up by wetting.
Vegetation cover: Vegetation holds the soil in place by forming a network of roots of plants. Rainfall on thick vegetation causes negligible soil erosion. Rain falling on bare land causes soil erosion as top soil is loose.
Soil mismanagement: The following techniques listed below contribute to soil mismanagement:
Faulty methods of soil drainage
Wrong methods of cultivation
Forest fires and
Removal of forest litter are common practices that aggravate soil erosion.
Erosion, floods and sedimentation result in deposition of silt and consequent clogging of irrigation canals.

Soil pollution: Soil pollution is defined as the reduction in productivity of soil due to presence of soil pollutants.

  • Pesticides, fertilizers, organic manure, chemicals, radioactive wastes, discarded food and clothes, leather goods, plastic, paper, bottles, tin cans and carcasses contribute towards soil pollution.
  • Industrial wastes contain chemicals like iron, lead, mercury, copper, zinc, cadmium, aluminum, cyanide's, acids, alkalies, etc that reach soil either directly through water or indirectly through air (acid rain).
  • Improper and continuous use of herbicides, fungicides and pesticides to protect crops from pests and fungi alter the basic composition of soils and make it toxic for plant growth.
  • Organic insecticides like DDT, Aldrin, Benzene-hexachloride, etc used against soil borne pests accumulate in the soil due to slow degradation by soil and water bacteria. They result in stunted growth of plants and reduced size of fruit. Their bye-products of degradation reach animals including man through food chain.
  • Radioactive wastes from mining and nuclear processes may reach soil via water or as 'fall-out'. From soil they reach plants and live stock from where they enter human beings through milk and meat. This causes retarded and abnormal growth in human beings.
  • Human and animal excreta used as organic manure to increase crop yield, pollute soil by contaminating soil and vegetable crops with pathogens that may be present in excreta.
  • Intensification of agricultural production by excessive irrigation, excessive fertilizers,  pesticides, insecticides, etc causes soil pollution.
  • Salination in the increase in the concentration of soluble salts in soil
  • It occurs mainly in arid areas due to:
    • Low rainfall
    • Poor drainage and
    • High temperature causing water to evaporate quickly leaving behind salts in high concentration
  • Salination occurs due to:
    • Poor drainage of irrigation and flood waters
    • In summers, salts from deeper strata are drawn up by capillary action and get deposited on the surface. Excess salts form a white crust on the soil surface and adversely affect the water absorbing capacity of the plant.
  • Salinity can be checked by improving drainage and saline lands can be reclaimed by the process of leeching with plenty of freshwater. By this technique, salts at the surface are leachead down to greater depths.
  • Excessive use of canal irrigation disturbs the water balance and creates a problem of water logging due to rise in water table. Water logging causes less oxygen available for respiration of plants.

Saturday, August 16, 2014

Multidisciplinary nature of Environmental Studies

Multidisciplinary nature of Environmental Studies
Environmental Studies is a multidisciplinary science because it comprises of various branches of studies such as chemistry, physics, medical science, life science, agriculture, public health, sanitary engineering, etc. It is the science of physical phenomena in the environment. It educates individuals from various walks of life about the delicate balance of nature and the recklessness with which we are damaging this environment thereby endangering our very existence. This has been illustrated in real life in the past and continues through the present age. Environment studies is a study of the sources, reactions, transport, effect and fate of human activities on biological species in air, water and soil. An understanding of the working of the environment require knowledge from wide ranging fields. The multidisciplinary nature of environment studies with respect to air pollution is shown in the table below:

Environmental issue / topic                                                 Major Subject

Nature and reaction of air pollutants                                          Chemistry and chemical engineering
Effects of air pollution on humans, animals and plants                  Zoology, Botany, and various branches of                                                                                                    life science, physics and chemistry
Effects of air pollutants on materials                                           Chemistry and chemical engineering
Effects of air pollution on climate                                                Mathematical modelling
Air pollution control devices                                                       Physics, Chemistry and various branches of                                                                                                  engineering
Economic effects of Air pollution                                                Economics, Demography
Conservation of resources and pollution control                          Various branches of physical and political                                                                                                     science
Alternative fuels                                                                          Various branches of physical science.