Environmental Sciences CIE 1072 Course Notes PDF

ENVIRONMENTAL SCIENCES CIE – 1072 Course Instructor: Dr. Chythanya Krishnan Concept of Environment  Environmental Sciences as a multidisciplinary approach Life Sciences Physical Sciences Biology Chemistry Biochemistry...

ENVIRONMENTAL SCIENCES CIE – 1072 Course Instructor: Dr. Chythanya Krishnan Concept of Environment  Environmental Sciences as a multidisciplinary approach Life Sciences Physical Sciences Biology Chemistry Biochemistry Physics Microbiology Earth Science Biotechnology Environmental Atmospheric Science Oceanography Engineering Sciences Geography Civil Chemical Maths Hydraulics Economics Statistics Sociology Mechanical Data Science Law Demography Education Computer science Mass communication Management Local nature of Environment ❖ Impact of mining on a locality ❖ Disposal and management of solid waste issues ❖ Impacts of hydro-electric / nuclear / thermal power plant in a community ❖ Arsenic / lead /heavy metal pollution of groundwater storage ❖ Water logging and salinization of soil ❖ River or lake pollution from nearby industry or human dwellings ❖ Soil erosion ❖ Wildfires ❖ Landslides ❖ Droughts / Floods ❖ Deforestation ❖ Impact of fertilizer / pesticide on the local residents near the agricultural field Individual Nature of environment Clean air, water and fertile land Hygienic living conditions Healthy and sustainable food Food security Public Awareness - Government bodies alone cannot bring about conservation practices without public participation. Public awareness – address the environmental issues within various sectors of public. Campaigns, Non government Organizations (NGO), College Eco-clubs, social media and posters etc.. Means of awareness. Renewable energy sources are replenished naturally and can be utilized indefinitely because their supply is essentially infinite. These sources are considered sustainable and environmentally favorable. a. Solar Energy: Solar panels generate electricity from sunlight. b. Wind Energy: Wind turbines generate electricity by harnessing the kinetic energy of the wind. c. Hydropower: The passage of water through dams or other water infrastructure generates energy. d. Biomass: To generate energy, organic materials such as biomass, agricultural residues, and refuse are burnt or converted into biofuels. e. Geothermal Energy: Earth's internal heat is used to generate electricity or heat structures. f. Forest resources: wildlife - flora and fauna provides numerous ecological, medicinal and economic uses. Nonrenewable energy sources are limited and will deplete over time. They will not get replenished if extracted exponentially by humans. Their combustion releases greenhouse as well as other toxic gases leading to a negative impact to the environment. a. Fossil Fuels: Coal, oil, and natural gas fall under this category. They are composed of the remains of extinct vegetation and animals and, when incinerated, emit carbon dioxide and other contaminants. They are the primary energy sources in many regions of the globe. b. Nuclear Energy: Nuclear energy is generated through nuclear fission. Although it does not produce greenhouse gas emissions, there are hazards associated with nuclear waste and accidents. Major concerns with Non-Renewable energy Sources and their generation: 1. Greenhouse gas emissions 2. Land and soil degradation -owing to mining of these resources 3. Air pollution from their combustion 4. Waste Disposal 5. Oil Spillage 6. Vicinity to human settlements 7. Accidents 8. Acid rain 9. Health hazards Sustainability, environmental impact, and availability are the main distinctions between renewable and nonrenewable energy sources. Renewable sources are more sustainable and have a lower environmental impact than nonrenewable sources, which are limited and have a greater environmental impact. Due to concerns about climate change, pollution, and resource depletion, the transition from non-renewable to renewable energy sources is a global priority. It is believed that increasing the use of renewable energy can mitigate/reduce these issues.  Forest Resources : For both human well-being and the welfare of our planet, forests provide a vast array of valuable resources. Here are several of the most important applications of forest resources: Forests are a significant supplier of timber and natural products. For construction materials, furniture, paper, and other wood-based products, trees are harvested.  Non-Timber Forest Products (NTFPs): Non-timber forest products include seeds, fruits, fungi, medicinal plants, resins, and natural pigments. Conservation of Biodiversity: Forests are home to an extensive number of animal and plant species. Water Resources: Watershed forests regulate water volume and quality. They reduce erosion, filter pollutants, and maintain potable, irrigation, and industrial water supplies. Forests perform an essential function in sequestering carbon dioxide from the atmosphere, thereby mitigating climate change. They function as carbon sinks by storing carbon in their trees and soils for extended periods of time. Forests provide numerous opportunities for recreation and tourism, such as hiking, camping, birdwatching, and ecotourism. This leads to economic benefits for local communities.  Ecosystem Services: Forests provide essential habitat for numerous species and a variety of ecosystem services, such as pollination, insect control, and nutrient cycling. Bioenergy: Wood and plant materials from forests can be utilized as biofuels and biomass for energy production, thereby reducing dependence on fossil fuels. Numerous indigenous and traditional communities obtain medicinal flora and botanical remedies from forest resources. Forests are a rich source of medicinal plants. Cultural and Spiritual Significance Forests are culturally and spiritually significant to numerous communities across the globe. They serve as sites for rituals, ceremonies, and traditional practises frequently. Hunting and Fishing: Forests provide opportunities for hunting and fishing, which can be essential to survival in some regions.  For scientific inquiry and environmental education, forests are essential. They offer the chance to investigate ecosystems, fauna, and the influence of humans on the environment. Conservation of Forest resources is crucial for the present and future generations as well. Sustainable forest management strives to balance between the rate of resource extraction and conservation practices. Deforestation - process of clearing or removing forests or trees from a particular area: mainly for human activities. Environmental Effects of Deforestation: Loss of Biodiversity: One of the most immediate and critical consequences of deforestation is the loss of biodiversity and may leads to their extinction. Climate Change: Forests act as carbon sinks, absorbing and storing large amounts of carbon dioxide. When forests are cleared or burned, this stored carbon is released into the atmosphere, contributing to global greenhouse gas emissions and climate change. Disruption of Water Cycles: Forests play a crucial role in regulating water cycles. They absorb rainfall, reduce runoff, and release water gradually, helping to prevent floods and droughts. Deforestation can disrupt these cycles, leading to water quality and quantity issues.  Soil Erosion: Tree roots help anchor soil, preventing erosion. When forests are removed, especially on steep slopes, soil erosion becomes a significant problem, degrading the quality of soil and causing sedimentation in nearby water bodies. Loss of Medicinal Plants: Many medicinal plants are found in forests, and their loss due to deforestation can have consequences for traditional medicine practices and pharmaceutical research. Social and Economic Effects of Deforestation: Displacement of Indigenous Peoples: Indigenous communities often rely on forests for their livelihoods, culture, and traditional knowledge. Deforestation can lead to the forced displacement of these communities, often with serious consequences for their well- being. Loss of Livelihoods: Many people depend on forests for their livelihoods, including those engaged in forestry, agriculture, and the collection of non-timber forest products. Deforestation can lead to job losses and economic hardships for local residents. Deforestation can lead to changes in local climates like factors like altered rainfall patterns, soil degradation, and increased pest problems.  Overgrazing – local Raw Materials for people may only Industrial use – afford to graze their Fuel Requirements- and tea plantation livestock in the woods Exponential land requirements demand for fuel wood Causes of Deforestation Mining Activities Shifting agriculture – people clear forest and Growing food needs does farming and Developmental – extensive leave the land Projects agriculture / cash hydroelectric crops in the forest projects (Dams). area Wildfire /Forest Tunnels,Road fires construction  Water Resources – Renewable Source :https://www.researchgate.net/figure/Distribution-of- Earths-water-Reference-2_fig1_332910952  Negative Impacts ✓ Deforestation and loss of Impacts of Big Biodiversity Dams ✓ Water Logging and salinity ✓ Flash floods ✓ Change in water flow and siltation ✓ Reservoir induces Seismicity ✓ Submergence of village and Positive Impacts fertile lands Prevention of Floods ✓ Displacement of local Employment residents Electricity Generation ✓ Resettlement issues Irrigation water supply ✓ Outbreak of vector borne Drinking water supply diseases - Malaria, Dengue Promotion of Navigation Promotion of Tourism, Promotion of Fisheries  The hydrological-cycle Source: https://civilsolution.wordpress.com/2013/02/06/the-hydrological-cycle/ The Hydrological Cycle Base flow Source: https://link.springer.com/referenc eworkentry/10.1007/978-3-319- 39312-4_158 The hydrological cycle / water cycle is the mechanism by which water moves from the Earth's surface to the atmosphere and then returns to the ground. The sun facilitates a continuous transfer of moisture between the seas, land, and atmosphere by supplying energy. Hydrology is the science that encompasses the occurrence, distribution, movement and properties of the waters of the earth and their relationship with the environment within each phase of the hydrological cycle. The various processes involved in the hydrological cycle are; 1. Evaporation 2. Transpiration 3. Condensation 4. Precipitation 5. Interception 6. Run-off 7. Infiltration 8. Percolation 9. Base Flow 1.Evaporation :Evaporation is the process by which water transitions from a liquid state to a gaseous one. The quantity of natural evaporation in any geographic location is primarily influenced by solar radiation, as well as other elements like air temperature, vapour pressure, wind, and atmospheric pressure. Evaporated moisture is lifted into the atmosphere from the ocean, land surfaces, and waterbodies as water vapour. 2. Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves (stomata) , where it changes to vapor and is released to the atmosphere. Normally, transpiration through stomata and evaporation from the surface of the leaves occurs simultaneously thereby referring as evapo- transpiration from trees or plants. 3. Condensation : Condensation is the process by which water vapor changes it's physical state from a vapor, most commonly, to a liquid. Water vapor condenses onto small airborne particles to form dew, fog, or clouds. The most active particles that form clouds are sea salts, atmospheric ions caused by lightning, and combustion products containing sulfurous and nitrous acids. Condensation is brought about by cooling of the air or by increasing the amount of vapor in the air to its saturation point 4. Precipitation : Precipitation is the process that occurs when any and all forms of water particles fall from the atmosphere and reach the ground. There are two sub- processes that cause clouds to release precipitation, the collide-coalescence process and the ice- crystal process. 5. Interception :Rainfall interception is the fraction of rain that falls onto vegetation but never reaches the ground, instead evaporating from the wet canopy. Interception is significant in forest as the forest canopy intercepts the precipitation / rainfall and moderate the local hydrology. Large-scale Deforestation thus affects this part of hydrological cycle. 6. Surface Runoff : Runoff occurs when there is excessive precipitation and the ground is saturated (cannot absorb any more water). The water flows over land and reaches rivers, lakes or oceans. Some runoff evaporates into the atmosphere. 7. Infiltration refers to the movement of water from the Earth's surface into the soil- surface. The process of infiltration holds significance in several areas such as irrigation, pollutant migration, groundwater replenishment, and ecosystem sustainability. 8. Percolation is the vertical movement of water through the soil itself to the deeper sub-surface layers /rocks. Percolation of rainfall leads to groundwater storage. 9. Base Flow: The lateral movement of groundwater within the sub-surface and joining the sea / water bodies https://rainfalltogroundwater.net/water-yield-vs-baseflow-augmentation/  While water vapour condenses to form dew drops or frost/ice, the below two mechanisms occurs: 1. Collision-coalescence process 2. Ice-crystallization process 1. Collision-coalescence process Large Collector drops collide with smaller drops. When collisions occur, drops either bounce apart or coalesce into one larger drop. Collision and coalescence together form the primary mechanism for precipitation in the tropics, where warm clouds dominate. 2. Ice-crystallization process Cold clouds are referred to those have temperature below freezing point or 0ºC throughout and consist entirely of ice crystals, supercooled droplets, or a mixture of two. Supercooled water and ice crystals grow to form larger ice crystals – the process is called Bergeron process or ice-crystallization process.  Ice Crystallization / Source: https://geography4u.com/types-of-precipitation-and-rainfall/ Aquifer: An aquifer is a porous, water-saturated layer of sand, gravel, or bedrock, which contains groundwater or has flowing groundwater. A geological formation in the earth that holds and transmits water. Aquifer is a saturated formation as all the pores are filled with water. Top soil is an Unsaturated zone – where both air and water are filled between pores. Thus it is not an aquifer and do not provide groundwater when pits are dug in the top soil. ❖ Unconfined Aquifers Where groundwater is in direct contact with the atmosphere through the open pore spaces of the overlying soil or rock, then the aquifer is said to be unconfined. The upper groundwater surface in an unconfined aquifer is called the water table and is open to atmospheric pressure. The depth to the water table varies according to factors such as the topography, geology, season and tidal effects, and the quantities of water being pumped from the aquifer. Unconfined aquifers are usually recharged by rain or streamwater infiltrating directly through the overlying soil. Typical examples of unconfined aquifers include many areas of coastal sands and alluvial deposits in river valleys. Confined aquifers are permeable rock units that are usually deeper under the ground than unconfined aquifers. They are overlain by relatively impermeable rock or clay that limits groundwater movement into, or out of, the confined aquifer. Groundwater in a confined aquifer is under pressure and will rise up inside a borehole drilled into the aquifer. An artesian flow is where water flows out of the borehole under natural pressure. Confined aquifers may be replenished, or recharged by rain or streamwater infilitrating the rock at some considerable distance away from the confined aquifer. Groundwater in these aquifers can sometimes be thousands of years old. Aquiclude – Aquiclude- geologic formation which may contain water, but is incapable of transmitting water. Example : Clay, granite, marble Source: https://www.researchgate.net/figure/Figure-A-2-Cross-section-sketch-of-a-typical- ground-water-flow-system-showing-the_fig1_255948122 Source: https://theconstructor.org/geotechnical/types-geological-formations- groundwater/34672/  Mineral Resources A mineral is a natural inorganic solid with a specific internal structure, a chemical composition and characteristic physical properties. Minerals and metals finds applications as follows: 1. Development of industrial plants and machinery 2. Generation of energy e.g., coal, lignite, uranium 3. Construction, housing, settlements, 4. Defense equipment – weapons, armaments 5. Transportation means 6. Communication - telephone wires, cables, electronics Source :https://ohiodnr.gov/discover-and-learn/rock- minerals-fossils/minerals devices 7. Medicinal system – particularly in Ayurvedic system 8. Formation of alloys e.g., steel alloys 9. Agriculture as fertilizers, equipments. 10.Jewelry – gold, silver, diamond, platinum Source: https://www.neetprep.com/ncert/1605-General-Principles-Processes-Isolation-Elements-General- Principles-Processes-Isolation-Elements--NCERT-Chapter-PDF Critical minerals - required for Strategic minerals – required for economy defense Iron, Aluminum, Copper, Gold, Silver Manganese, Cobalt, Platinum, Chromium Mining – extraction of minerals and fossil fuels. Deep deposits – sub-surface mining Shallow deposits – surface mining 1. Open pit mining – machines dig holes and remove the ores – for minerals like copper, iron, limestone, sandstone, marble, granite 2. Dredging – chained buckets and draglines extract underwater minerals – sand and for minerals in aqueous solution like gold. 3. Strip mining – ore is stripped off by Open pit mining using bulldozers, power shovels, stripping wheels - for phosphate rocks Source: https://www.shutterstock.com/search/strip-mining  Dredging Mining Strip mining Source: https://www.shutterstock.com/search/strip-mining  Mining accident due to landslide in China Source :https://news.rthk.hk/rthk/en/compon ent/k2/1689056-20230222.htm Source :https://insideclimatenews.org/news/15032022/coal-mining- methane/. A deep coal mine Ecological Impacts of Mining 1. Devegetation and defacing of landscape – The topsoil as well as vegetation are removed from the mining area to get access to the deposit. While large scale deforestation leads to landslides and soil erosion, the landscape is also deeply affected. The debris and tailings along with big scars(marks due to movement and pit) and disruptions spoil the aesthetic value of the region and make it prone to soil erosion. 2. Subsidence of land: This is mainly associated with underground mining. Subsidence of mining areas often results in tilting of buildings, cracks in houses, buckling of roads, bending of tail racks and leaking of gas from cracked pipe-lines leading to serious disasters. 3. Groundwater Contamination – Impurities such as Sulphur gets converted to sulphuric acid through microbial action making water acidic. Also, heavy metals leach into the soil thereby contaminating the groundwater storage. 4. Surface water pollution – The acidic water along with wastes from mines may contain metals like Uranium, Mercury which gets carried away into the nearby streams or rivers. These poses detrimental effects to aquatic life in the nearby streams / rivers and makes water unfit for drinking and human consumption. 5. Air pollution – Metals are separated and sometimes purified in the mining sites itself. During this process enormous quantities of air pollutants mainly dust, aerosols, soot, arsenic particles, cadmium, lead, Sulphur Oxides, Suspended particulate matter (SPM), gets released in the mining site causing air pollution. 6. Loss of flora nd fauna – Plant and animal population gets adversely affected due to massive deforestation and landscape disruptions resulting in loss of biodiversity. And ecosystem degradation. 7.Noise pollution – Dynamite blasting and deep mining excavation results in loud noises and disturbances to daily life of the people in the surrounding locality. 8.Soil pollution – revegetation, leaching of unwanted mining wastes results in loss of soil fertility and its natural characteristics leading to soil contamination. Socio-economic Impacts from mining 1. Encroachment and evacuation – Due to possibility of the accidents or sinking of the land, people have to displaced in and around the mining area. Mining can encroach on the lands of indigenous communities, leading to land rights disputes and cultural impacts. 2. Rehabilitation and resettlements –People who have been made to move cannot fully recover and improve their income and living standards just by getting paid more compensation buy concerned authorities. 3. Depletion of Resources: Several extracted resources, such as fossil fuels and certain metals, have a limited supply and cannot be replenished. Excessive exploitation may result in the exhaustion of resources. 4. Human Rights and Social Concerns : Labor Conditions: Miners often work in challenging and sometimes hazardous conditions. Issues like worker safety, fair wages, and labor rights are concerns in many mining regions. 5. Occupational health hazards - Exposure to mining-related pollutants, including dust and chemicals, can pose health risks to both miners and nearby communities. Miners are at risk of developing a lung disease called pneumoconiosis because of their exposure to airborne respirable dust. Health hazards like Asbestosis, Silicosis Occupational cardiovascular diseases, Lead toxicity, Neurotoxic disorders, Noise-induced hearing loss, Dermatologic conditions, Psychological disorders, Severe occupational traumatic injuries, etc.. also exists 6. Transparency and Accountability: Some mining operations lack transparency, making it difficult to track environmental and social impacts or hold companies accountable for their actions. 7. Accidents- Mining accidents can have devastating consequences for both workers and the environment. Explosions: Mining operations involving flammable gases (e.g., methane in coal mines) can lead to explosions. These explosions are often caused by ignition sources like electrical equipment or sparks from machinery. Roof and Rib Falls: In underground mines, the collapse of the roof or ribs (the sides of the mine) is a significant hazard. This can happen due to weak geological conditions, inadequate roof support, or improper mining methods. Fires: Fires in mines can result from various sources, including electrical faults, equipment overheating, or the combustion of flammable materials. The confined and often inaccessible nature of underground mines makes firefighting challenging. Haulage Accidents: Accidents involving the transportation of materials, machinery, or personnel in and out of mines can result from equipment malfunctions, operator error, or inadequate safety measures. Falls: Slips, trips, and falls are common accidents in mining operations. These can occur on uneven terrain, ladders, scaffolding, or during the operation of heavy machinery. Equipment Accidents: Malfunctions or improper use of heavy mining equipment and machinery can lead to accidents, including crushing injuries, collisions, and equipment rollovers. Tunnel and Shaft Collapses: The structural integrity of tunnels and shafts is crucial to prevent collapses, which can be deadly for miners working underground.  1.Agriculture and Food Resources Agriculture is the science or practice of farming, including the cultivation of the soil for crop production and the nurturing of livestock for food, fiber and other products. Food security is achieved via agriculture, which is the major source of food production. A stable and productive agricultural sector is critical for guaranteeing global food security, eliminating hunger, and avoiding food shortages, especially in vulnerable areas. Nutrition and Health: Agriculture provides a varied variety of nutrients required for human health in addition to calories. A varied diet rich in fruits, vegetables, grains, and animal products improves general nutrition and well-being. Agriculture contributes significantly to global economic growth. It employs a sizable section of the global population and provides a source of income for millions of individuals, particularly in developing nations. Agriculture provides a source of income and may help fuel economic development and poverty alleviation. Agriculture is a source of food energy, but it is also a source of bioenergy. Crops such as maize, sugarcane, and oilseeds are utilised to make biofuels, which may be used instead of fossil fuels. This improves energy security while also lowering greenhouse gas emissions. Agriculture is the backbone of many rural communities, and its success is inextricably linked to the well-being of these communities. A flourishing agriculture industry may aid rural development by creating employment and infrastructure. Cultural and Social Significance: Agriculture is deeply rooted in the culture and traditions of many societies. It plays a crucial role in shaping identity, heritage, and social structures in rural areas. Global Trade: Agriculture and food are international commodities, and global trade in agricultural products is essential for supplying regions with what they cannot produce themselves. This global trade is vital for ensuring a variety of food products year-round. https://geopoliticalfutures.com/food-insecurity-outlook-for-2023/ The food gap between advanced and developing economies is growing. Developed countries tend to have stronger currencies and better access to credit, meaning food supplies and input materials are generally more affordable and accessible than in developing economies. The most vulnerable countries, however, are often forced to work with institutions like the International Monetary Fund to secure financing to pay for imports. Countries that rely on food imports and have low foreign reserves are at greatest risk of seeing a lack of access to food. Costly agricultural input materials, labor and energy also contribute to high food costs. https://www.smilefoundationindia.org/blog/are-philanthropic-efforts-sufficient-to-curb-issues- such-as-world-hunger/  Impacts of Overgrazing and Agriculture Impacts of Overgrazing : Livestock plays a crucial role in rural life. The huge population of livestock needs to be fed and the demand for grazing lands rises. Overgrazing occurs when livestock feeds on grasslands or pasture ;lands beyond the carrying capacity or renewal capacity of such lands. Impacts of overgrazing are: 1. Land Degradation – Overgrazing removes the vegetal cover over the soil resulting in reduced fertility, poor dry and compacted soil. Also continuous movement of livestock results in compaction of soil –causing blockage to rain water percolation to deeper soil layers. 2. Soil erosion –Grasses and plants hold top soil through their roots. Due to overgrazing by cattle and other livestock, the cover of 3. Loss of useful species – Plant population gets adversely affected by overgrazing and unscientific grazing methods. Indigenous plant of useful value may get replaced by thorny plants or weeds. Example: As a result of overgrazing in vast areas in Arunachal Pradesh and Meghalaya in India are getting invaded by thorny bushes weeds etc.. of low nutritional values.  Impacts of Agriculture It usually employs small tools, pot, Traditional naturally available water, organic Agriculture fertilizers It makes use of hybrid high yielding Modern seeds and plat varieties, fertilizers, agriculture high-tech equipments, pesticides, irrigation water  Impacts of Traditional Agriculture Deforestation – Traditional farming usually clears a part of forest and burn. The crops are grown in the burnt land. The land is left and new forest cover is cleared for next farming season. This method is called slash and burn or shifting cultivation. This results in deforestation. Soil Erosion – Clearing of forest cover for traditional agriculture results in floods, erosion due to strong winds or heavy rainfall. Depletion of nutrients – During shifting cultivation, the land loses its fertility due to nutrient intake by crops grown. This cultivated land is left untreated without any fertilizer treatment resulting in loss of fertility. The farmers shift their farming to a new land by clearing forest. Impacts of modern Agriculture Impacts from High Yielding variety of plants Impacts from Fertilizers Impacts from Pesticides Water logging problems Salinity Problems  1. Impacts from High Yielding variety of plants : The use of high yielding variety of crops result in monoculture –only that crop is grown in vast areas. Any attack from pests or pathogen on this variety will result in crop destruction over vast areas leading to economic loss and food insecurity issues. Also preference to genetically modified and hybrid crop variety will cause reduced preference for cropping of local indigenous variety of the same crop.  1. Impacts from Fertilizers a. Micronutrient imbalance - Most of the chemical fertilizers used in modern agriculture have nitrogen, Phosphorous and Potassium which are essential macronutrients. Farmers use excessive fertilizers to boost crop growth. High amounts of such nutrients result in imbalance to micronutrients like Zinc. Example is Punjab and Haryana. b. Nitrate Pollution – Nitrogenous fertilizers applied in the fields often leach deep down into the groundwater causing its pollution. The nitrates concentrated in the water if exceeds 25mg/liter, causes health hazard called Blue baby syndrome causing infant deaths. This problem is very prevalent in Denmark, England, France and Netherlands. In India also this exists. c. Eutrophication – Excessive use of nitrogen and phosphorous gets washed off to nearby water bodies. These nutrients nourishes the water bodies and causes fast growth of algae rapidly. The algal species rapidly flourish over the water surface consuming Oxygen in the process. Also sunlight is prevented from reaching the water body depths due to algal bloom over the surface – the condition called Eutrophication. This results in devastation of the aquatic ecosystem and deaths of fish species. 3. Impacts from Pesticides – Thousands of pesticides are used in agricultures such as Sulphur, arsenic, lead , mercury and DDT a. Resistance to pesticides and super pests – Over the years the pests become resistant to pesticides. Over 20 species of pests are known to resistant to variety of pesticides. They are called” Super Pests”. b. Death of non-target organisms – Many pesticides kills non target organisms which are not pests to crops, example –honeybees, butterflies. c. Biomagnification – Many pesticides are non-biodegradable and keep accumulating in the food chain , process called biomagnification. Since humans belong to the highest level in the food chain, they get the pesticides accumulated in their bodies.  4. Water logging problems – Over-irrigation of the farmlands by farmers for good crop growth leads to water logging. Inadequate drainage in such areas results in increased water accumulation in the groundwater storage and water table rises resulting in loose soil and crop yield reduces. Example: In Punjab and Haryana –excessive canal irrigation led to water-logging problems. 5. Salinity Problems – Excessive fertilizers and irrigation leads to increased soil salinity. Salts such as sodium chloride, sodium sulphide calcium chloride, magnesium chloride are found in high amounts in irrigated areas of the world. Increased salinity results in pH imbalance of soil. Irrigation water unlike rainwater is not pure and contains salts. Not all the salts are taken up by the plants. When the irrigated water dries out the salts remain in the soil.