India consists 1/25th of world’s water resources. The total utilizable water resources of the country are assessed as 1086 km3. A brief description of surface and groundwater water resources of India is given below.
Surface Water Resource
- India’s average annual surface run-off generated by rainfall and snowmelt is estimated to be about 1869 Billion Cubic Meter (BCM). However, it is estimated that only about 690 BCM or 37 per cent of the surface water resources can actually be mobilised.
- This is because:
- Over 90 per cent of the annual flow of the Himalayas rivers occur over a four month period and Potential to capture such resources is complicated by limited suitable storage reservoir sites.
- The main source of surface water is precipitation.
- About 20 percent part of the precipitation evaporates and mixes with the environment.
- The large part of surface water is found in rivers, river lets, ponds and lakes. Remaining water flows into the seas, oceans. Water found on the surface is called surface water.
- About two–third of the total surface water flows into three major rivers of the country – Indus, Ganges and Brahmaputra’s. The water storage capacity of reservoirs constructed in India so far is about 17,400 billion cubic meters.
- The storage capacity of usable water in the Ganges basin is the maximum, but in spite of maximum annual flow, the storage capacity of usable water is the least in Brahmaputra’s basin.
- The storage capacity in Godavari, Krishna, Mahanadi and Indus is sufficient.
- If storage capacity of usable water is seen in terms of ratio, then of Tapi river basin is 97 percent.
Ground Water Resources
A lot of the Earth’s water is found underground in soil or under rock structures called aquifers. Groundwater pollution is often caused by pesticide contamination from the soil, this can infect the drinking water and cause huge problems.
The total Annual Replenishable ground water resources of the Country have been estimated as 431 Billion Cubic Meter (BCM).
Keeping 35 BCM for natural discharge, the net annual ground water availability for the entire Country is 396 BCM. The Annual ground water draft is 243 BCM out of which 221 BCM is for irrigation use and 22 BCM is for domestic & industrial use.
- Water is an easy solvent, enabling most pollutants to dissolve in it easily and contaminate it. The most basic effect of water pollution is directly suffered by the organisms and vegetation that survive in water, including amphibians.
- Each day over 1000 children die of diarrheal sickness in India and the numbers have only increased alarming in the last five years. Water is polluted by both natural as well as man-made activities. Volcanic eruptions, earthquakes, Tsunamis etc are known to alter water and contaminate it, also affecting ecosystems that survive under water.
- The abuse of lakes, ponds, oceans, rivers, reservoirs etc. is water pollution. Pollution of water occurs when substances that will modify the water in negative fashion are discharged in it. This discharge of pollutants can be direct as well as indirect.
- The groundwater utilization is very high in the states of Punjab, Haryana, Rajasthan, and Tamil Nadu.
- However, there are States like Chhattisgarh, Odisha, Kerala, etc., which utilize only a small proportion of their groundwater potentials. States like Gujarat, Uttar Pradesh, Bihar, Tripura and Maharashtra are utilizing their ground water resources at a moderate rate.
- If the present trend continues, the demands for water would need the supplies. And such situation, will be detrimental to development, and can cause social upheaval and disruptions
SOURCES OF WATER POLLUTION
There are various classifications of water pollution. The two chief sources of water pollution can be seen as Point and Non Point:
- Point refers to the pollutants that belong to a single source. An example of this would be emissions from factories into the water.
- Non Point on the other hand means pollutants emitted from multiple sources. Contaminated water after rains that has traveled through several regions may also be considered as a Non-point source of pollution.
Microbiological water pollution:
- usually a natural form of water pollution caused by microorganisms.
- Many types of microorganisms live in water and cause fish, land animals and humans to become ill.
- Microorganisms such as: Bacteria, Viruses, Protozoa.
Essential for plant growth and development. Many nutrients are found in wastewater and fertilizers, and these can cause excess weed and algae growth if large concentrations end up in water. This can contaminate drinking water and clog filters.
- Some pollutants do not dissolve in water as their molecules are too big to mix between the water molecules. This material is called particulate matter and can often be a cause of water pollution.
- The suspended particles eventually settle and cause thick silt at the bottom.
Chemical water pollution:
- Metals and solvents from industrial work can pollute rivers and lakes. These are poisonous to many forms of aquatic life and may slow their development, make them infertile or even result in death.
- Pesticides are used in farming to control weeds, insects and fungi. Run-offs of these pesticides can cause water pollution and poison aquatic life Subsequently, birds, humans and other animals may be poisoned if they eat infected fish.
- Petroleum is another form of chemical pollutant that usually contaminates water through oil spills when a ship ruptures. Oil spills usually have only a localized effect on wildlife but can spread for miles. The oil can cause the death of many fish and stick to the feathers of seabirds causing them to lose the ability to fly.
Causes of Water Pollution
- Industrial waste: Industries produce huge amount of waste which contains toxic chemicals and pollutants which can cause air pollution and damage to us and our environment. They contain pollutants such as lead, mercury, Sulphur, asbestos, nitrates and many other harmful chemicals. Many industries do not have proper waste management system and drain the waste in the fresh water which goes into rivers, canals and later in to sea. The toxic chemicals have the capability to change the color of water, increase the amount of minerals, also known as Eutrophication, change the temperature of water and pose serious hazard to water organisms.
- Sewage and waste water: The sewage and waste water that is produced by each household is chemically treated and released in to sea with fresh water. The sewage water carries harmful bacteria and chemicals that can cause serious health problems. Domestic households, industrial and agricultural practices produce wastewater that can cause pollution of many lakes and rivers.
Pathogens are known as a common water pollutant; the sewers of cities house several pathogens and thereby diseases. Microorganisms in water are known to be causes of some very deadly diseases and become the breeding grounds for other creatures that act like carriers. These carriers inflict these diseases via various forms of contact onto an individual. A very common example of this process would be Malaria.
- Religious and Social Practices:
Religious faith and social practices also add to pollution of Indian River waters. Carcasses of cattle and other animals are disposed in the rivers. Dead bodies are cremated on the river banks. Partially burnt bodies are also flung into the river. All this is done as a matter of religious faith and in keeping with ancient rituals. These practices pollute the river water and adversely affect the water quality.
Mass bathing in a river during religious festivals is another environmentally harmful practice. The biochemical oxygen demand (BOD) goes up drastically when thousands of people simultaneously take a ‘holy dip’. Religious practices also demand that offerings from a puja be immersed in a river. It is now common to see people immersing offerings in plastic bags. Plastic bags are very dangerous and further add to the pollution load of the river.
- Mining activities: Mining is the process of crushing the rock and extracting coal and other minerals from underground. These elements when extracted in the raw form contain harmful chemicals and can increase the amount of toxic elements when mixed up with water which may result in health problems. Mining activities emit several metal waste and sulphides from the rocks and is harmful for the water.
- Marine dumping: The garbage produce by each household in the form of paper, aluminum, rubber, glass, plastic, food if collected and deposited into the sea in some countries. These items take from 2 weeks to 200 years to decompose. When such items enter the sea, they not only cause water pollution but also harm animals in the sea.
- Accidental Oil leakage: Oil spill pose a huge concern as large amount of oil enters into the sea and does not dissolve with water; there by opens problem for local marine wildlife such as fish, birds and sea otters. For e.g. a ship carrying large quantity of oil may spill oil if met with an accident and can cause varying damage to species in the ocean depending on the quantity of oil spill, size of ocean, toxicity of pollutant.
- Burning of fossil fuels: Fossil fuels like coal and oil when burnt produce substantial amount of ash in the atmosphere. The particles which contain toxic chemicals when mixed with water vapor result in acid rain. Also, carbon dioxide is released from burning of fossil fuels which result in global warming.
- Chemical fertilizers and pesticides: Chemical fertilizers and pesticides are used by farmers to protect crops from insects and bacteria’s. They are useful for the plants growth. However, when these chemicals are mixed up with water produce harmful for plants and animals. Also, when it rains, the chemicals mixes up with rainwater and flow down into rivers and canals which pose serious damages for aquatic animals.
- Leakage from sewer lines: A small leakage from the sewer lines can contaminate the underground water and make it unfit for the people to drink. Also, when not repaired on time, the leaking water can come on to the surface and become a breeding ground for insects and mosquitoes.
- Global warming: An increase in earth’s temperature due to greenhouse effect results in global warming. It increases the water temperature and result in death of aquatic animals and marine species which later results in water pollution.
- Radioactive waste: Nuclear energy is produced using nuclear fission or fusion. The element that is used in production of nuclear energy is Uranium which is highly toxic chemical. The nuclear waste that is produced by radioactive material needs to be disposed off to prevent any nuclear accident. Nuclear waste can have serious environmental hazards if not disposed off properly. Few major accidents have already taken place in Russia and Japan.
- Urban development: As population has grown, so has the demand for housing, food and cloth. As more cities and towns are developed, they have resulted in increased use of fertilizers to produce more food, soil erosion due to deforestation, increase in construction activities, inadequate sewer collection and treatment, landfills as more garbage is produced, increase in chemicals from industries to produce more materials.
- Leakage from the landfills: Landfills are nothing but huge pile of garbage that produces awful smell and can be seen across the city. When it rains, the landfills may leak and the leaking landfills can pollute the underground water with large variety of contaminants.
- Animal waste: The waste produce by animals is washed away into the rivers when it rains. It gets mixed up with other harmful chemicals and causes various water borne diseases like cholera, diarrhea, jaundice, dysentery and typhoid.
- Underground storage leakage: Transportation of coal and other petroleum products through underground pipes is well known. Accidentals leakage may happen anytime and may cause damage to environment and result in soil erosion.
Water pollutants also include both organic and inorganic factors. Organic factors include volatile organic compounds, fuels, waste from trees, plants etc. Inorganic factors include ammonia, chemical waste from factories, discarded cosmetics etc.
The water that travels via fields is usually contaminated with all forms of waste inclusive of fertilizers that it swept along the way. This infected water makes its way to our water bodies and sometimes to the seas endangering the flora, fauna and humans that use it along its path.
The current scenario has led to a consciousness about water preservation and efforts are being made on several levels to redeem our water resources. Industries and factory set-ups are restricted from contaminating the water bodies and are advised to treat their contaminated waste through filtration methods. People are investing in rain water harvesting projects to collect rainwater and preserve it in wells below ground level.
WATER RESOURCES MANAGEMENT– CHALLENGES/ISSUES IN THE COUNTRY
The major challenges/issues associated with the water resources management and development in the country is varied and complex and could be categorized as follows:
- Natural situation (Tropical Monsoon climate) – Causes large scale spatial and temporal variation in water availability, recurring droughts and frequent floods.
- Human, Managerial and Developmental challenges – These is increasing water demand and falling per capita availability, water use and energy efficiency, deterioration of water quality, reduction or deterioration of available resources (loss of surface storage), increasing competition/conflict within sectors, under and inefficient utilization of irrigation potential, over exploitation and depletion of ground water resources, water-logging and soil salinity in irrigated lands, fragmentation of management of water/ management of shared resources, lack of spatial inventory for large number of water infrastructure in the country, currently used water resources potential estimates are old, significant change in land use / land cover, demographic and utilization pattern in past few decades.
- Climate change impact – Addressing the impact of climate change on water availability and economy. Analysis of scenarios for impacts on resources and use is required to evaluate water policies.
Water Pollution is common, and is an area of high alert. Water needs to be preserved undermining the sustainable development as concerns.
Some Water Treating Measures:
- Septic tanks and sewage treatments:
- Septic tanks treat sewage at the place where it is located, rather than transporting the waste through a treatment plant or sewage system. Septic tanks are usually used to treat sewage from an individual building.
- Untreated sewage from a property flows into the septic tank and the solids are separated from the liquid.
- Solid material is separated depending on their density. Heavier particles settle at the bottom of the tank whereas lighter particles, such as soap scum, will form a layer at the top of the tank.
- Biological processes are used to help degrade the solid materials.
- The liquid then flows out of the tank into a land drainage system and the remaining solids are filtered out.
- Industrial water treatment:
- Before raw sewage can be safely released back into the environment, it needs to be treated correctly in a water treatment plant.
- In a water treatment plant, sewage goes through a number of chambers and chemical processes to reduce the amount and toxicity of the waste
- The sewage first goes through a primary phase This is where some of the suspended, solid particles and inorganic material is removed by the use of filters.
- The secondary phase of the treatment involves the reduction of organic, this is done with the use of biological filters and processes that naturally degrade the organic waste material.
- The final stage of treatment is the tertiary phase; this stage must be done before the water can be reused.
Almost all solid particles are removed from the water and chemical additives are supplied to get rid of any left-over impurities.
- Ozone wastewater treatment:
- Ozone wastewater treatment is a method that is increasing in popularity. An ozone generator is used to break down pollutants in the water source
- The generators convert oxygen into ozone by using ultraviolet radiation or by an electric discharge field.
- Ozone is a very reactive gas that can oxidise bacteria, moulds, organic material and other pollutants found in water.
- Using ozone to treat wastewater has many benefits:
- Kills bacteria effectively.
- Oxidises substances such as iron and Sulphur so that they can be filtered out of the solution.
- There are no nasty odors or residues produced from the treatment.
- Ozone converts back into oxygen quickly, and leaves no trace once it has been used.
- The disadvantages of using ozone as a treatment for wastewater are:
- The treatment requires energy in the form of electricity; T
- This can cost money and cannot work when the power is lost.
- The treatment cannot remove dissolved minerals and salts.
- Ozone treatment can sometimes produce by-products such as bromate that can harm human health if they are not controlled.
- Denitrification is an ecological approach that can be used to prevent the leaching of nitrates in soil, this in turn stops any ground water from being contaminated with nutrients.
- Fertilizers contain nitrogen, and are often applied to crops by farmers to help plant growth and increase the yield.
- Bacteria in the soil convert the nitrogen in the fertilizer to nitrates, making it easier for the plants to absorb.
- Immobilization is a process where the nitrates become part of the soil organic matter.
- When oxygen levels are low, another form of bacteria then turns the nitrates into gases such as nitrogen, nitrous oxide and nitrogen dioxide
- The conversion of these nitrates into gas is called denitrification. This prevents nitrates from leaching into the soil and contaminating groundwater.
Sources – community waste water, Industrial waste, Agricultural chemicals waste, Thermal & nuclear pollution, Oil spills, Radioactive dump waste, Groundwater seepage etc.
- Sudden rise in water temperature due to thermal pollution, which uses water as coolant & releases hot water to source, kills aquatic animals as they have a very narrow tolerance limit with respect to temperature
- Polluted water reduces dissolved oxygen which leads to depletion of aquatic flora & fauna
- Oil spills in water can be cleaned with the help of Bregoli – a byproduct of paper industry
- Water hyacinth (an aquatic weed) can purify water by taking some toxic materials & a number of heavy metals from water.
Biochemical oxygen demand (BOD)
- amount of dissolved oxygen needed by bacteria in decomposing the organic waste present in water
- Actually a measurement of pollution by organic wastes expressed as milligram of oxygen / liter water
Higher value of BOD indicates low dissolved oxygen in water (BOD is only limited to biodegradable materials only)
Chemical oxygen demand
a measure of oxygen equivalent required for oxidation of total organic matter i.e. degradable & non degradable, present in water.
Diseases by Water Pollution
- A crippling deformity caused by methyl mercury poisoning mainly by industrial waste water
- first described in the inhabitants of Minamata Bay, Japan and resulted from their eating fish contaminated with mercury industrial waste
- Also known as ouch ouch disease (pain in bones & joints) caused by water contamination by cadmium
Blue Baby Syndrome
- Excess nitrates in drinking water reacts with hemoglobin to form nonfunctional methaemoglobin which impairs oxygen transport
- Excess of fluorides in drinking water can cause neuromuscular disorders, teeth deformity, and hardening of bones, painful joints & outward bending of legs from knees – Knock knee syndrome
Black foot disease
Caused by leaching of arsenic from soil & rocks to ground water used for drinking purposes
Water contaminated with lead
- Cause anemia, loss of muscle power & bluish lines around the gums
- Produced by nuclear tests, passed to vegetation & then appears in milk of the cattle that consume the contaminated vegetation & is passed to humans.
- causes serious damage to thyroid glands especially among children
Sick building syndrome (SBS)
- a situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified
- causes are frequently pinned down to flaws in the heating, ventilation & air conditioning (HVAC) systems
Pollution in Leather Industry
- Leather industry in India has become 0 discharge industry as ~80% of the effluents are treated and recycled back into use and remaining 20% are solidified and their salts used for other purposes.
- As a result, Indian leather industry is REACH compliant (EU norms) and exported $4.5 bio in 2011-12 and the target is $14 bio by 2015-16 (growth rate of 20% p.a.)