18. பலவழிகளில் மனிதன் நீைர மாச படததல்
10 மிலலயன் மககளககம் ேமலாக
கஙகா நதியில் தினமம்
களிககிறாரகள்.
தணி தைவததல் மறறம் களிததல்
பாஸேபட் மறறம் இதர பல
ரசாயனஙகைள நீாில் கலககச்
ொசயகிறத.
19. பலவழிகளில் மனிதன் நீைர மாச படததல்
விவசாயம்
பரவலான பகதியில்
உறபததியாகம் மாச
பசசி மரநதகள் மறறம் ரசாயன உரஙகள் நீரபபாசன
அலலத மைழ நீரடன் கலநதவிடகினறன .
அைவகள் நீரதேதகக நீைரயம், நிலததட நீைரயம் மாச
படததி விடகினறன . ைநடேரட் பாஸேபட் மறறம்
அழகாத ொசயறைகப் ொபாரளகள் தான் அநத மாசககள் .
விவசாயம் எனபத நிலததட நீைர
மாசபடததம் ஒர மககியமான
பிறபபிடமாகம்.
20. பலவழிகளில் மனிதன் நீைர மாச படததல்
ொதாழிறசாைலகள்
கறிபபிடட இடததில் உறபததியாகம்
மாசகக இத ஒர உதாரணம்.
விவசாய உறபததிப் ொபாரடகைள அடபபைடயாகக் ொகா ணட ொதாழிறசாைலகள் – அைவகளின்
கழவபொபாரடகள் மிக அதிக அளவில் கைரயம் அழகம் ொபாரடகைளக் ொகாணடரககம் .
விவசாய உறபததிப் ொபாரடகைள அடபைடயாகக் ொகாணட
ரசாயன உறபததி ொசயயம் ொதாழிறசாைலகள்– இைவகளின் ொபயரகைள நீஙகள் ொசாலல
சககைர, உணவ பதனிடதல், காகிதக் கழ் ொதாழிறசாைலகளின் சில கழவப் ொபாரடகைளச் மடயமா ?
சாியாக சததிகாிககாவிடல், அநத ரசாயனப் ொபாரடகள் நமத நிலம் மறறம்
மறறம் காகிதம், சததிகாிபப ஆைலகள்.
நீர் வளஙகைள அழிதத விடம்.
ொபடேரா லய சததிகாிபப நிைலயம்– இஙக பயனபடததபபடம் நீாில்
உளள எலலா எணைணகைளயம் பிாிதொதடதத பிறக தான், அநத நீைர
ொவளிேய நிலததில் பாய விடேவணடம். .....
சில ரசாயன உறபததிச்
ஆனால், அபபடச் ொசயயபபடகிறதா ??
மினாமதா
ொதாழிறசாைலகளின் ொபயரகைளச்
ொசாலலவம்.
ேநாய்
Minamata disease
21. பலவழிகளில் மனிதன் நீைர மாச படததல்
ொதாழிறசாைலகள்
கறிபபிடட இடததில் உறபததியாகம்
மாசகக இத ஒர உதாரணம்.
அனல் மின் நிைலயஙகள் – களிரபடதத நீர் ேதைவபபடகிறத .
அநத நீர் சடாககப் படகிறத . பிறக அத ொவளிேய உளள
ொபாிய நீர் நிைலகளில் விடம் ொபாழத , சறறப் பறச்
சழநிைலயின் தடப ொவபப சமநிைலயிைன மாறறி , அத
மிகநத பாதிபபிைன உணடாகககிறத .
இைதத் தான் அனல் மின் மாச எனற அைழககிேறாம் .
22. கழவ சததிகாிபப ஆைலகள்
ஒர ொதாழிறசாைலயிலரநத ொவளிேயவரம்
ரசாயனத் திரவக் கழவகள், கழிவ சததிகாிபப
ஆைலகளில் சததிகாிககப் படகினறன .
ொபாிய ொதாழிறசாைலகளில் அதன் உளேளேய
இநத சததிகாிபப நிைலயஙகள்
அைமநதிரககம்.
ஆனால், சிறிய ொதாழிற் கடஙகளில்
இததைகய நிைலயஙகைளத் தனியாக
அைமபபத மிகவம் ொசலைவ உணடாககம்.
சில ொதாழிறேபடைடகளில், சிறிய
ொதாழிறசாைலகள் கடடாக ஒனற ேசரநத ஒர
ொபாதவான கழவ சததிகாிபப நிைலையதைத
நிறவி இரபபாரகள்.
23. நிைனவடடல்
மனிதனால் நீர் மாசபட மடயம்
இயறைகயாகவம் நீர் மாசபடம்.
நீர் நிைலகளில் கழவ நீர்
கபைப ொகாடடதல்
தணி தைவததல், களிததல்
பசசி மரநதகள், ரசாயன உரஙகள்.
ொதாழிறசாைலகள்
24. வாரதைத விைளயாடட
வகபைப 5 கழககளாகப் பிாிககவம்.
ஒர நீைர மாசபடததம் ொபாரள் அலலத நீாில் ஏறபடம் மாசின் காரணம் இைவகளின் வாரதைதகளில் உளள எழததககளகக ஏறப ஒவொவார
வாரதைதகளககம் தனித் தனியாகச் சிறிய ேகாடகள் வைரயவம் .
A - கழ இநத விைளயாடைட ஆரமபிககம். அவரகள் ஒர எழதைத
ஊகிபபாரகள். அநத எழதத அநத வாரதைதயில் இரபபின், ஆசிாியர் அநத
எழதைத சாியான இடததில் ைவபபார்.
இலலாவிடல், அநத எழதத தனியாக ஒர பககததில் எழதபபடம் .
10 தவறான ஊகிபபகள் அதிக படசமாக அனமதிககப் படம் .
தனியாக எழதபபடடரககம் எழததகளின் எணணிகைககக ஏறப அநதக்
கழவகக மதிபொபண் கிைடககம். - அதிக மதிபொபண் – 10
கைறநத மதிபொபண் ொபறற கழ ொவறறி ொபறம் .
Water is capable of dissolving or suspending a variety of materials, so it’s pretty tough to get "pure" water. All water, outside of a research laboratory, will have some other substance in it.
Some in the form of minerals are good for our health while others may not be so beneficial. There are nearly infinite numbers of possible contaminants in drinking water. Here we will talk about contaminants that are not good for us.
Students can be encouraged to name things that they see in their homes that can dissolve in water
Some pollutants (typically organic pollutants) introduce and favour the growth of germs in water, which can cause diseases like typhoid, cholera and jaundice.
Others pollutants (typically inorganic pollutants) can collect in our bodies and affect our bones or cause diseases like cancer over time. These pollutants are excreted from our bodies very slowly and if the rate of intake is greater than the rate of excretion, they collect in our bodies. This process is called bio-accumulation. Higher concentration of these pollutants in our bodies results in chronic diseases like cancer, organ failure, nervous system disease etc.
Some contaminants may introduce a change in colour, taste or smell of water, but in many cases, especially inorganic contamination, such changes are not observed. Water contamination can be confirmed only by testing the water in a certified laboratory.
Examples of point source of pollution include discharges from a wastewater treatment plant, untreated effluent from a factory, leaking underground tanks, etc. They enter a water stream through a specific point.
Examples of non-point source of pollution include storm water runoff from agricultural fields and urban areas, or vehicular (air) pollutants that dissolve in water. Once cannot identify a specific location from where the pollutants are introduced into the water stream.
For the past several decades, focus was on reducing point sources of pollution. In recent years, greater attention has come to be placed on non-point source contributions, especially in rapidly urbanizing areas.
Natural sources of water pollution. The geology of a place can introduce inorganic contaminants into groundwater. As water seeps into the ground, if the rocks and soil are rich in compounds of fluoride, arsenic, iron etc, these compounds dissolve in the groundwater. When groundwater is extracted and used for drinking, these compounds enter our bodies.
Compounds of arsenic, fluoride etc. accumulate in our bodies over time due to bio-accumulation.
Natural pollution is a non-point source of pollution.
Excess fluoride in the groundwater is a problem being faced in most parts of India. Fluoride in small levels is required for healthy teeth and bones. That is why many toothpastes used to contain a small amount of fluoride. But when levels of fluoride are beyond an acceptable limit, they accumulate in our bodies and cause fluorosis. Fluorosis is of two types – dental and skeletal. In the initial stages, teeth started getting discoloured and with increasing concentrations, people get severely crippled. Though defluoridation kits are available, people living in fluoride affected areas are advised on counteracting the affects of fluoride contamination by diet restrictions – eating foods rich in Vitamin C, Calcium and iron and avoiding foods with black salt etc.
West Bengal and Bangladesh are affected by high arsenic concentration in groundwater. This causes arsenicosis in humans, which is a life threatening disease.
Such contamination is aggravated when there is excessive groundwater extraction. Concentrations of polluting compounds increase in the existing groundwater. People living in areas which have high levels of natural inorganic pollution in groundwater are advised to recharge their groundwater reservoirs with rainwater, so that the concentration of the salts in the groundwater reduces.
Most of water used in a home comes out as waste water – black water (sewage) and grey water from sinks, bath water, waste water from washing clothes etc. Our waste water treatment systems are inadequate. Excess untreated waste water is either led into surface water bodies (lakes, ponds, rivers, seas), or into the soil. This contaminates surface and ground water.
Sewage contains pathogens which can cause diseases like cholera, typhoid, jaundice etc.
Grey water from washing contains phosphates and other chemicals which assist organic growth. This leads to eutrophication of water bodies like lakes and ponds.
Increase in sewage content in the soil can result in contamination of groundwater sources with nitrates. Nitrate contamination can result in dangerous diseases like blue-baby syndrome. (Under certain conditions, consumed nitrate gets reduced to nitrite, which reacts with haemoglobin and reduces the capacity of blood to carry oxygen. When pregnant women drink nitrate contaminated water, it affects the baby and the baby can even die if adequate oxygen does not reach the brain.)
There is also increased solid waste generation (industrial and domestic). This waste is either thrown into surface water bodies or is left in waste dumps. Chemicals seep down from these waste dumps into the soil and into our groundwater resources, contaminating them.
People bathing and washing of clothes also contaminates surface water bodies. Soaps and detergents have phosphates which are nutrient rich and can cause eutrophication of surface water bodies.
Agriculture uses large quantities of pesticides and fertilizers. Water used for irrigating farms, or rainwater that falls on these lands dissolves the fertilizers and pesticides and seeps into the ground contaminating the soil and groundwater with pollutants like nitrates, phosphates and non degradable synthetic organic pollutants.
Nitrogen based fertilizers are commonly used in India. Nitrogen is converted to nitrate. Excess nitrate that cannot be used by the crop leaches into soil and groundwater. Nitrate contamination of water can cause the blue baby syndrome.
We invented insecticides, herbicides and fungicides to save our crops from pests and to save ourselves from diseases. Crop yields increased and pests like mosquitoes were destroyed. The pesticide industry grew to become a multi-billion dollar industry. We then started finding different kinds of cancers, birth defects and other medical problems. Studies across the globe showed pesticides to be the culprit. Pesticides contain complex organo-chlorides and other heavy metals that bioaccumulate and biomagnify up the food chain. Over time, their concentration in our bodies increase beyond safe levels and cause serious health problems most of which are fatal.
Agriculture is one of the most important sectors in India and the use of pesticides is rampant. World over pesticide production is reducing but in India it is still on the rise. We continue to use pesticides that are banned in other parts of the world. Untrained farmers overuse pesticides and are ignorant about the ill-effects of use and handling of pesticides. Today pesticides are considered the foremost chemical threat to our groundwater.
We also use some pesticides in our homes – can you name one? (Insect sprays)
Industrial processes also use a lot of water and the resultant effluents are not treated to the required extent in many cases. Some industries let out untreated effluent into municipal sewage drains and the municipal waste water treatment systems are geared to handle only sewage, not these chemical – laden wastes. The output of the municipal wastewater treatment systems ends up in surface water bodies, which are contaminated by these untreated chemicals.
Some industries may let out untreated effluent directly into water bodies, polluting them and others may let it out into the soil, from where it seeps into our groundwater resources.
Wastes from agro industries contain many organic substances which are nutrient rich. These wastes boost the growth of weedy species of plants in surface water bodies and can result in eutrophication.
Water is required for the process of cooling in power plants and during this process, its temperature increases slightly. This water, when released into a water body, alters its temperature and affects the ecosystem, which is in a state of delicate balance. Even a change of 1 -2 degrees centigrade of the water can alter the aquatic ecosystem considerably.
Industries are supposed to treat their wastewater before releasing it into a water body. This treatment is done in ‘effluent treatment plants’, which are custom designed to handle the type and quantity of wastes generated by a particular industry. Larger industries usually have effluent treatment plants but medium and small scale industries find this a very expensive proposition. Due to the high cost, most medium and small scale units do not have effluent treatment plants and release untreated wastewater into municipal drains, surface water bodies or soil. Some industrial estates have tried to make a common effluent treatment plant which can be used by a group of industries together, but there have been technological issues due to the waste constituents, its quantity and the frequency at which the wastes are released.
