Environmental Concerns PDF

ENVIRONMENTAL CONCERNS 1 WHAT ARE ENVIRONMENTAL CONCERNS/ISSUES? Environmental issues are defined as problems with the planet’s systems (air, water, soil, etc.) that have developed as a result of human interference mistreatment of the planet....

ENVIRONMENTAL CONCERNS 1 WHAT ARE ENVIRONMENTAL CONCERNS/ISSUES? Environmental issues are defined as problems with the planet’s systems (air, water, soil, etc.) that have developed as a result of human interference mistreatment of the planet. 2  ENERGY RESOURCES AND ISSUES Energy Resources are all forms of fuels used in the modern world, either for heating, generation of electrical energy, or for other forms of energy conversion process. Energy resources can be classified in two categories: renewable and non-renewable  2 Categories of Energy Renewable energy resources such as wind, water, solar, and geothermal, come from sources that generate as fast are they consumed and are continuously available. Some, such as biofuel produced from food crops and other plants, are replenished every growing season. Non-renewable energy resources such as fossil fuels and nuclear material are removed from the earth and can be depleted. These resources have been the most used type of energy in the modern era.  Environmental Impacts of Energy Resources Wind Energy Wind power or wind energy is the use of wind to provide mechanical power through wind turbines to turn electric generators for electrical power. IMPACT As with all energy supply options, wind energy can have adverse environmental impacts, including the potential to reduce, fragment, or degrade habitat for wildlife, fish, and plants. Furthermore, spinning turbine blades can pose a threat to flying wildlife like birds and bats. Due to the potential impact that wind power can have on wildlife, and the potential for these issues to delay or hinder wind development in high-quality wind resource areas, addressing impact minimization, siting, and permitting issues are among the wind industry’s highest priorities.  Environmental Impacts of Energy Resources Solar Energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever- evolving technologies such as solar heating, photovoltaic, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis. IMPACT Using solar energy can have a positive, indirect effect on the environment when solar energy replaces or reduces the use of other energy sources that have larger effects on the environment. However, some toxic materials and chemicals are used to make the photovoltaic (PV) cells that convert sunlight into electricity. Some solar thermal systems use potentially hazardous fluids to transfer heat. Leaks of these materials could be harmful to the environment.  Environmental Impacts of Energy Resources Geothermal Energy Geothermal power is power generated by geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. IMPACT The environmental effects of geothermal development and power generation include the changes in land use associated with exploration and plant construction, noise and sight pollution, the discharge of water and gases, the production of foul odours, and soil subsidence.  Environmental Impacts of Energy Resources Biomass Energy Biomass is plant or animal material used as fuel to produce electricity or heat. IMPACT Despite being a relatively clean alternative to more harmful fossil fuels, biomass still generates harmful toxins that can be released into the atmosphere as it's combusted. This release of greenhouse gases may be a secondary environmental impact from biomass energy generation, but it's important nonetheless.  Environmental Impacts of Energy Resources Hydro Energy Hydropower or water power is power derived from the energy of falling or fast-running water, which may be harnessed for useful purposes. IMPACT Hydroelectric facilities can have huge impacts on the environment by changing the use of the land, which has knock- on effects on surrounding areas. Impoundment facilities require flooding huge areas, with the size of the generators and topography of the land dictating the scope of the reservoir. Those in flat areas also require more land than hilly areas, where deeper reservoirs can hold more water in a smaller space. Flooding destroys forests, wildlife habitats and agricultural land, even important natural areas. It can also require relocating whole communities..  Environmental Impacts of Energy Resources A fossil fuel is a fuel formed by natural Fossil fuel Energy processes, such as anaerobic decomposition of buried dead organisms, containing organic molecules originating in ancient photosynthesis that release energy in combustion. IMPACT Burning fossil fuels emits a number of air pollutants that are harmful to both the environment and public health. Sulfur dioxide (SO2) emissions, primarily the result of burning coal, contribute to acid rain and the formation of harmful particulate matter. Environmental Impacts of Energy Resources Coal Energy Coal is a combustible black or brownish- black sedimentary rock with a high amount of carbon and hydrocarbons. Coal is classified as a non-renewable energy source because it takes millions of years to form. IMPACT Burning coal emits large amounts of carbon dioxide into the atmosphere. Coal is composed almost entirely of carbon, so burning coal unleashes large amounts of carbon dioxide (CO2) into the atmosphere. These emissions have been shown to increase the greenhouse effect in the atmosphere and lead to global warming.  Environmental Impacts of Energy Resources Nuclear Energy Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. IMPACT The main environmental impact of nuclear power is related to building the plant, fuel procurement and the thermal load of cooling water discharged into the sea during operation. Of these three things, the most significant environmental concern is the thermal load on the sea caused by the cooling water.  Environmental Impacts of Energy Resources Natural Gas Energy Natural gas is a fossil energy source that formed deep beneath the earth's surface. Natural gas contains many different compounds. The largest component of natural gas is methane, a compound with one carbon atom and four hydrogen atoms (CH4). IMPACT One of the biggest disadvantage of natural gas is that it emits carbon dioxide which is bad for our atmosphere. Constant introduction of carbon dioxide into our atmosphere will lead to climate change and also global warming. SOLID WASTE MANAGEMENT 16 17  WHAT IS SOLID WASTE? Solid wastes are all wastes arising from human and animal activities that are normally solid and that are discarded as useless or unwanted. Waste: Depending on their physical state they are classified as: Liquid wastes Gaseous wastes Solid wastes 18 INTRODUCTION Solid Waste Management is defined as the discipline associated with control of generation, storage, collection, transport or transfer, processing and disposal of solid waste materials in a way that best addresses the range of public health, conservation, economics, aesthetic, engineering and other environmental considerations. 19 PROPER SEGRATION OF WASTE Waste segregation is included in law because it is much easier to recycle. Effective segregation of wastes means that less waste goes to landfill which makes it cheaper and better for people and the environment. It is also important to segregate for public health. The Republic Act (RA) 9003, otherwise known as the Ecological Solid Waste Management Act of 2000, provides the necessary policy framework, institutional mechanisms and mandate to the local government unites (LGUs) to achieve 25% waste reduction through establishing an integrated solid waste management plans based on 3Rs (reduce, reuse and recycling). 20  Management of Solid Waste  Refuse-refers to any disposable materials, which includes both recyclable and non-recyclable materials. This term is often interchangeably with waste, but refuse is a broad, overarching term that applies to anything that is leftover after it is used, while waste only refers to leftovers that cannot be recycled. Reuse- is the action or practice of using an item, whether for its original purpose or to fulfil a different function. It should be distinguished from recycling, which is the breaking down of used items to make raw materials for the manufacture of new products. Recycle- Recycling is the process of collecting and processing materials that would otherwise be thrown away as trash and turning them into new products. Recycling can benefit your community and the environment. Reduce- Waste reduction, also known as source reduction, is the practice of using less material and energy to minimize waste generation and preserve natural resources. Waste reduction is broader in scope than recycling and incorporates ways to prevent materials from ending up as waste before they reach the recycling stage. 21 Classification of Solid Waste: ✓ Based on their source of origin:  Residential wastes  Commercial wastes  Institutional wastes  Municipal wastes  Industrial wastes  Agricultural wastes ✓ Based on physical nature:  Garbage  Ashes  Combustible and non-combustible wastes  Demolition and construction wastes  Hazardous wastes 22 METHODS FOR TREATMENT OF SOLID WASTE: With different types of wastes, different treatment methods are applied. These treatment processes has been listed below:  Open Dumps  Landfills  Anaerobic Digestion  Composting  Vermicomposting  Encapsulation  Incineration 23 Open Dumps Open dumps refers to uncovered areas that are used to dump solid waste of all kinds. The waste is untreated and not separated. It is breeding ground for files, rats, and other insects that OPEN DUMP SITE spreads disease. 24  Landfills A landfills may also refer to the ground that has ben filled in with soil and rocks instead of waste materials, so that it can be used for a specific purpose, such as for building houses. Landfill, also known as dump or tip, is a site for disposal of waste materials by burial. LANDFILLS 25  Sanitary Landfills Sanitary landfills are designed to greatly reduce or eliminate the risks that waste disposal may pose to the public health and SANITARY LANDFILLS environmental quality. 26  Composting Composting is the biological decomposition of organic waste under controlled aerobic condition. Compost is the end product obtained after subjecting the organic fraction of solid waste to aerobic or anaerobic decomposition to yield humus like solid, carbon dioxide, water vapour, and energy. 27  Anaerobic Digestion Anaerobic digestion is a regulated version of the natural events of landfill, in that it results in the controlled release of methane-rich biogas, which offers the potential for a very real form of energy from waste. It is carried out in a large fermented tanks. 28  Vermicomposting Vermicomposting is a simple biotechnological process of composting in which certain species of earthworms are used to enhance the process of waste conversion and produce a better end product. Vermicomposting differs from composting in several ways. Utilizing microorganisms/ earthworms 29 Encapsulation Solid particulate waste material is coated with a thermosetting resin which is compressed and cured to form a rigid core. The rigid core is coated with a flexible thermoplastic resin to provide a sealed encapsulated waste agglomerate which can withstand compressive loads. 30 Encapsulation Encapsulation methods are of the types:  Microencapsulation- is a process in which tiny particles or droplets are surrounded by a coating to give small capsules, with useful properties. In general, it is used to incorporate food ingredients, enzymes, cells or other materials on a micro metric scale.  Macroencapsulation- refers to PCMs encapsulated in any type of container such as tubes, spheres, or panels, which can be incorporated into building materials or serve as heat exchangers by themselves. The size of these containers is usually larger than 1 cm. 31 Incineration Incineration is the most common thermal treatment process. It is burning of the waste in the presence of oxygen so as to eliminate all odours and to ensure good combustion. After incineration the wastes are converted to carbon dioxide, water vapour and ash. It converts hazardous organic substances into less hazardous components. 32  Pollution Pollution introduces types of contaminants into natural environment that causes unfriendly change. It can be of types: Chemical substance or energy. Pollutant is waste material that pollutes air, water and soil. Different types of pollution that are caused by natural events (like forest fire) or by man-made activities. These are further classified into: Air Pollution; Water Pollution; Soil Pollution; Noise 33 Pollution. POLLUTION AS A GLOBAL PROBLEM 34  POLLUTION AIR POLLUTION Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles. Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, volcanoes and wildfires. 35  Activities that causes Air Pollution The Burning of Fossil Fuels One of the ways that humans cause the most air pollution is by burning fossil fuels. Fossil fuels include coal, oil, and natural gas. When we burn fossil fuels this releases all sorts of gasses into the air causing air pollution such as smog. Industrial Emission Industrial pollution can also impact air quality, and it can enter the soil, causing widespread environmental problems. Wildfires It plays a key role in shaping ecosystems by serving as an agent of renewal and change. But fire can be deadly, destroying homes, wildlife habitat and timber, and polluting the air with emissions harmful to human health. Fire also releases carbon dioxide a key greenhouse gas into the atmosphere. Transportation The potential negative impacts of transportation on environment can be listed as degradation of air quality, greenhouse gas emissions, increased threat of global climate change, degradation of water resources, noise and habitat loss and fragmentation. Agricultural activities Agriculture affects air quality and the atmosphere in four main ways: particulate matter and GHGs from land clearance by fire (mainly rangeland and forest) and the burning of rice residues; methane from rice and livestock production; nitrous oxide from fertilizers and manure; and ammonia from manure and urine. 36 Health Effect of Air Pollution Polluted air can have permanent health effects such as: Accelerated aging of the lungs. Loss of lung capacity and decreased lung function. Development of diseases such as asthma, bronchitis, emphysema, and possibly cancer. 37  ENVIRONMENTAL EFFECT OF AIR POLLUTION Global Warming Climate Change Acid Rain Smog effect Deterioration of fields Extinction of animal species Respiratory health problems Deterioration in building materials 38  Preventing Air Pollution ✓ Use smokeless fuels like LPG, PNG (Piped Natural Gas). ✓ Installation of Solar water heaters to obtain hot water. ✓ Air pollution from motor vehicles can be reduced by using Compressed Natural Gas (CNG). ✓ Air pollution from factories, industries, thermal power stations, oil refineries, etc. can be controlled by washing their smoke and waste gases with jets of water. ✓ The air pollution can be controlled by using non-polluting sources of energy like Solar energy, Wind energy, and Hydro energy for generating electricity. 39  POLLUTION WATER POLLUTION Water Pollution occurs when harmful substances— often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment. Cause of Water Pollution Industrialization, discharge of domestic waste, radioactive waste, population growth, excessive use of pesticides, fertilizers and leakage from water tanks are major sources of water pollution. These wastes have negative effects on human health. Water pollutant is unwanted and harmful substances which make the water impure. 40  Activities that Causes Water Pollution Industrial Waste Waste water from manufacturing or chemical processes in industries contributes to water pollution more seriously, contaminated water destroys aquatic life and reduces its reproductive ability. Marine Dumping If garbage is dumped into the ocean, the oxygen in the water could be depleted. This results in poor health for marine life due to lack of oxygen. Oil leakage Oil spill poses a huge threat to marine life when a large amount of oil spills into the sea and does not dissolve in water. The burning of fossil fuel Fossil fuels like coal and oil, when burnt, produce a substantial amount of ash in the atmosphere. The particles which contain toxic chemicals when mixed with water vapour result in acid rain. 41 Health Effect of Water Pollution Bacterial, viral and parasitic diseases like typhoid, cholera, encephalitis, poliomyelitis, hepatitis, skin infection and gastrointestinal are spreading through polluted water. It is recommended to examine the water quality on regular basis to avoid its destructive effects on human health. 42  ENVIRONMENTAL EFFECTS OF WATER POLLUTION Destruction of biodiversity Water pollution depletes aquatic ecosystems and triggers unbridled proliferation of phytoplankton in lakes — eutrophication —. Contamination of the food chain Fishing in polluted waters and the use of waste water for livestock farming and agriculture can introduce toxins into foods which are harmful to our health when eaten. Lack of potable water The UN says that billions of people around the world have no access to clean water to drink or sanitation, particularly in rural areas. Disease The WHO estimates that about 2 billion people have no option but to drink water contaminated by excrement, exposing them to diseases such as cholera, hepatitis A and dysentery. Infant mortality According to the UN, diarrhoeal diseases linked to lack of hygiene cause the death of about 1,000 children a day worldwide. 43  Preventing Water Pollution ✓ Preventing disposal of polluted water into the river. ✓ Installation of water treatment plants in all industrial areas. ✓ Follow 3R’s mantra- Reduce, Reuse and recycle. ✓ Laws of industrial unit should be strictly imposed in order to prevent polluted water not to disposed directly in to river and lakes. ✓ Educate the public about its harmful effect to human and the environment. 44 END 45  BIODIVERSITY BIO = LIFE DIVERSITY = VARIETY 46 Biodiversity- what is it? ▪ Variety of life in our natural environment from smallest micro-organism, including the ecosystems where they live- forest, mountains, rivers and seas. ▪ Variety within between species. 47  Levels of Biodiversity ▪ Genetic Diversity ▪ Species Diversity Genetic diversity is the total number of The number of species or genetic characteristics in the genetic organisms per unit area found in makeup of a species, it ranges widely different habitats of the planet. from the number of species to differences within species and can be attributed to the span of survival for a species. 48 Ecosystem Diversity Ecosystem diversity deals with the variations in ecosystems within a geographical location and its overall impact on human existence and the environment. Ex: Forest, rivers, mangroves, marine, wetland, etc. 49 50  What benefits can we get from Biodiversity? ▪ Biodiversity feeds the World ▪ In the olden days, humans had over 10,000 species for food. ▪ Today, about 30 crops provide our body’s energy requirements; 40 species of mammals and birds domesticated for food; 14 species account for 90% of livestock production. 51  ▪ Biodiversity provides air and water ▪ Forest generate the oxygen that we breathe. ▪ Forest and mountains provide aquifers- source of water we drink Biodiversity provides camlness Nature tripping Mountain climbing Hearing the chirping of the birds Comfort in nature 52  ▪ Biodiversity brings income to people ▪ Livelihood (Selling fish, fruits, vegetables, etc.) ▪ Forestry, Agriculture and fisheries ▪ Biotechnology, Pharmaceuticals ▪ Ecotourism Biodiversity give us shelter Fiber Timber Bamboo Cogon Anahaw Rattan 53  5 Major Threats to Biodiversity ▪ Climate Change Changes in climate throughout our planet's history have, of course, altered life on Earth in the long run — ecosystems have come and gone and species routinely go extinct. But rapid, manmade climate change speeds up the process, without affording ecosystems and species the time to adapt. For example, rising ocean temperatures and diminishing Arctic sea ice, affects marine biodiversity and can shift vegetation zones, having global implications. Overall, climate is a major factor in the distribution of species across the globe; climate change forces them to adjust. But many are not able to cope, causing them to die out. 54  How to Deal the Climate Change? ▪ 1. Take a good hard look at your carbon footprint Instead of just guessing what it takes to reduce your personal carbon emissions, know exactly what you and your household are responsible for, and what you can change. Everything from size of your home, the efficiency of your appliances, how much you drive or fly, what you eat, and how much you recycle can make a big difference in your personal carbon footprint. ▪ Do these things now to limit your carbon emissions. Now that you have a handle on your personal carbon spew, figure out where you can reduce emissions. At home, change lights to energy-efficient bulbs, replace power-hungry appliances, insulate your home to reduce heating and air conditioning costs, consume food that doesn't require as much transportation, and eat less meat, which has a significantly higher carbon footprint than fruits and vegetables. 55 ▪ Deforestation and Habitat Loss Deforestation is a direct cause of extinction and loss of biodiversity. An estimated 18 million acres of forest are lost each year, due in part to logging and other human practices, destroying the ecosystems on which many species depend. What can we do to lessen deforestation? The solutions to deforestation mostly lie in policy — companies and corporations can adopt best practices and refuse to use timber and paper suppliers that contribute to deforestation. 56 ▪ Over exploitation Overhunting, overfishing and over-harvesting contribute greatly to the loss of biodiversity, killing off numerous species over the past several hundred years. Poaching and other forms of hunting for profit increase the risk of extinction; the extinction of an apex predator — or, a predator at the top of a food chain — can result in catastrophic consequences for ecosystems. What can we do to lessen over exploitation? Conservation and continued awareness surrounding overexploitation, especially poaching and overfishing, are key. Governments need to actively enforce rules against such practices, and individuals can be more conscious of what they eat and purchase. 57 ▪ Invasive Species The introduction of non-native species into an ecosystem can threaten endemic wildlife (either as predators or competing for resources), affect human health and upset economies. What can we do to the increasing number of invasive species? According to the National Wildlife Federation, solutions include creating systems to prevent introduction of invasive species in the first place, effectively monitoring for new infestations and swiftly eradication newly detected invaders. 58 ▪ Air and Water Pollution From the burning of fossil fuels (releasing dangerous chemicals into the atmosphere and, in some cases, depleting ozone levels) to dumping 19 billion pounds of plastic into the ocean every year, pollution completely disrupts the Earth's ecosystems. While it may not necessarily cause extinction, pollutants do have the potential to influents species' habits. What can we do to lessen air and water pollution? The average person can do a number of things to fight atmospheric and hydrologic pollution, such as recycling, conserving energy at home and using public transportation 59 TOXIC AND HAZARDOUS WASTE MANAGEMENT 60 Introduction ▪ Hazardous-waste management, the collection, treatment, and disposal of waste material that, when improperly handled, can cause substantial harm to human health and safety or to the environment. Hazardous wastes can take the form of solids, liquids, sludges, or contained gases, and they are generated primarily by chemical production, manufacturing, and other industrial activities. ▪ Hazard waste is waste with properties that make it dangerous or capable of having a harmful effect on human health or the environment. Examples include drain cleaners, oil paint, motor oil, antifreeze, fuel, poisons, pesticides, herbicides, and rodenticides. 61  Source of Hazardous Waste Hazardous waste is generated from many sources, ranging from industrial manufacturing process wastes to batteries and may come in many forms, including liquids, solid, gases, and sludges. It includes ◼ Clinical wastes ◼ Waste oils/water, hydrocarbons/water mixtures, emulsions; ◼ Wastes from the production, formulation and use resins, latex, plasticizers, glues/adhesives. ◼ Wastes resulting from surface treatment of metals and plastics. ◼ Residues arising from industrial waste disposal operations. ◼ Wastes which can contain certain compounds such us: copper, zinc, cadmium, mercury, lead and asbestos. ◼ Household waste; or Residues arising from the incineration of household waste. 62  Concern about Hazardous Waste ◼ Causes of mass life and material damage and loss ( disability, death, fire, explosion) ◼ Cause of environmental damages; water, solid and air pollution ◼ Cause of potential increased chemical bioaccumulation that is hard for biodegradability (chlorine containing chemicals) ◼ Cause of long term irreversible health risks ◼ High concern of trans-boundary movement of toxic waste ◼ Cause of massive toxic health damages 63  How to classify whether the waste is Hazardous or not? ◼ Using defined list of criteria ( as specified by US-EPA) ◼ Identifying components of waste ◼ Based on characteristics of waste ◼ Reviewing literature about the inherent characteristics of waste Classification of Hazardous waste 1. Listed waste by US Environmental Protection Agency (US-ESPA) 2. Characterized waste 3. Universal Waste 4. Mixed waste: Radioactive + Hazardous 5. E-Waste: Electrical waste, Electronic waste 64  US-EPA list of Hazardous Waste ◼ F-List Wastes on this list are created from common manufacturing and industrial processes. Because these wastes are produced in multiple industries, they are known as “non-specific source waste”. ◼K-List Wastes, including sludge or waste water from a selection of specific industries, such as petroleum refining or pesticides manufacturing, are included on the list. Since we know the industry they are produced in, they are called “ source specific wastes”. ◼P-list and U-list Wastes on this list are commercial chemical products being discarded in their unused form. They become hazardous when discarded. Characteristics of Hazardous Waste  Explosive  Reactive  Flammable and Ignitable  Radioactive  Corrosive  Bio accumulate  Poisonous  Toxic  Eco toxic 65  Infectious Substances  Types of Hazardous Waste  Nuclear Waste  Industrial Waste 66  Types of Hazardous Waste  Universal Waste  Medical Waste 67  Types of Hazardous Waste  Construction Waste  Electronic Waste 68  Effect of Hazardous waste  Human Health Environment Cancer Global warming Respiratory problems Air pollution Heart disease Water pollution Exposure effect Treatment of Hazardous waste  1. Physical treatment- on the other hand, concentrates, solidifies, or reduces the volume of the waste. Physical processes include evaporation, sedimentation, flotation, and filtration. 2. Chemical treatment- include ion exchange, precipitation, oxidation and reduction, and neutralization. 3. Thermal treatment-is any waste treatment technology that involves high temperatures in the processing of the waste feedstock. 4. Biological treatment- organic wastes, such as those from the petroleum industry, is also an option. One method used to treat hazardous waste biologically is called land farming. 69 5. Disposal method- commonly used are discussed along with design criteria to be taken when designing either a solid or a hazardous waste.  Soil Erosion Introduction ▪ Soil erosion is the washing or blowing away (by wind or water) of the top layer of soil (dirt). ▪ Erosion also leaves large holes in the earth, which can weaken buildings and even cause them to collapse. ▪ Soil erosion is a natural process. It becomes problem when human activity causes it to occur much faster than under natural conditions. ▪ Soil erosion occurs when soil is removed through the action of wind and water at a greater rate than it is formed. If the soil has eroded, the crops will not grow very well 70 Soil Erosion 71  What is Soil Erosion? ▪ When a raindrops hits soil that is not protected by a cover of vegetation and where there are no roots to bind the soil, it has the impact of a bullet. ▪ Soil particles are loosened, washed down the slope of the land and either end up in the valley or are washed away out to sea by streams and river. ▪ Erosion removes the topsoil first. Once this nutrients-rich layer is gone, few plants will grow in the soil again. ▪ Without soil and plants the land becomes desert like and unable to support life. 72  Causes of Soil Erosion Wind and water are the main agents of soil erosion. The amount of soil they can carry away is influenced by two related factors: ✓speed- the faster either moves, the more soil it can erode ✓ Plant cover- plants protect the soil and in their absence wind and water can do much more damage. Erosion occurs when farming practices are not compatible with the fact tha soil can be washed away or blown away. These practices are: ◼ Overstocking and overgrazing ◼ Inappropriate farming technique ◼ Lack of crop rotation 73 ◼ Planting crops down the contour instead of along it  Types of Erosion Sheet Erosion Rill Erosion The removal of a uniform layer of The process where numerous soil from the surface by runoff. small cuts are formed. Rills can be several inches deep. Gully Erosion The accumulation of water in Channel Erosion narrow cuts which removes the The scouring of stream banks or soil to considerable depth. drainage ways by increased These cuts can be several feet water flows. deep. 74 ▪ Sheet Erosion ▪ Gully Erosion ▪ Rill Erosion ▪ Channel Erosion 75  Prevention ✓ Planting wind breaks can be effective. ✓ Allow indigenous plants to grow along riverbanks. ✓ Cultivate land, using a crop rotation system. ✓ Encourage water infiltration and reduce water runoff. ✓ Make sure that there are always plants growing in the soil, and that soil is rich in humus. ✓ Avoid overgrazing. 76  Importance of Plants in Controlling Soil Erosion Plants provide protective cover on the land and prevent soil erosion for the following reason: ▪ Plants slow down waster is it flows over the land and this allows much of the rain to soak into the ground. ▪ Plants roots hold the soil in position and prevent it from being washed away. ▪ Plants break the impact of a raindrop before it hits the soil, thus reducing its ability to erode. ▪ Plants in wetlands and on the banks of rivers are of particular importance as they slow down the flow of the water and their roots bind in the soil, thus preventing soil. 77 Biological Magnification 78  What is Biological Magnification? Biological Magnification, also known as Bio magnification, is the increase of substances that occurs in food chains. These substances are usually found in contaminated environments. Substances, such as pesticides and mercury, are absorbed by organisms due to their environment or the food they consume. The substance then accumulates inside the cells. When an organism higher in the food chain eats multiple organisms below, each of them containing some of the toxins, the toxins becomes more concentrated in the higher food chain. Since this continues throughout the food chain, organisms higher in the food chain are the ones who will obtain the most toxins. 79  Bioaccumulation Biological Magnification is often related with Bioaccumulation, which is the increase of the toxic substance in an organism’s body. These two terms are different: - Accumulation pertains to harmful substances in a living organism's body and its effects. - Magnification deals with the substance being passed along the food chain. Bioaccumulation will cause a number of problems within the body 80 that contains it.  How Bio magnification affects animals? How Bio magnification affects animals A common example of Bio magnification and Bioaccumulation is the use of DDT in the 1960's and 1970’s. DDT, or dichlorodiphenyltrichloroethane, was overly used by humans as a pesticide. It soon found its way into the environment. DDT and other toxins eventually climbed up the food chain, and affected the bald eagles, nearly driving them to extinction. The DDT was absorbed by organisms which the bald eagles hunted, such as fish and carrion. Each bald eagle would eat multiple numbers of these fish and carrion. The DDT would accumulate inside each of the eagles' bodies. The DDT would sterilize the birds or cause them to make fragile eggs that would break easily. This caused the birds population to dwindle rapidly. 81 How DDT rises in a food chain 82  Mercury Mercury is a natural substance, that is found in very small quantities in the ocean. Human interference with the environment, causes higher levels of mercury in the ocean. Algae, a producer, consistently absorbs the mercury which is found in its environment. However, it excretes it slowly. Often, zoo plankton will consume the algae and the mercury along with it. The plankton is then consumed by small fish, which is in turn consumed by larger fishes. Eventually, the fishes end up on human dinner tables. Humans, who consume fishes high in mercury, will easily become ill from mercury poisoning. 83 The Biological Magnification of DDT in a marine ecosystem 84  Toxins that Bio magnify DDT and Mercury are not the only toxin that biomagnifies. Other examples include, but are not limited to: PCB'S (polychlorinated biphenyls): used in insulators, as a plasticizer, and fire retardant. It biomagnifies, impairs reproduction and is widespread in aquatic systems. Cyanide is used in leaching gold and in fishing. It is a dangerous toxin and is known to have effects on coral reefs. Selenium is concentrated by farming desert soils. It is toxic and causes reproductive failures in organisms. Heavy metals such as mercury, copper, nickel, zinc, and lead affect the nervous system and they may affect reproduction. 85  Why we should care? Ironically, bio magnification and bioaccumulation are caused by humans but also have a profound impact on us. It can lead to neurological effects such as mental retardation in infants who contract it through their mothers. A weakened immune system is also the result of bio magnification. Some cancers are also linked through ingesting these toxins. It can also lead to organ failure in both animals and humans. Since some animals have weaker immune systems then humans, they will die faster which can lead to extinction if it continues. 86  Prevention of Bio magnification In an attempt to eradicate bio magnification, the U.S. and several countries worldwide have placed a ban on the use of DDT. People are trying to prevent harmful substances such as oil and human waste from being dumped in water. Landfills are also trying to get rid of these substances because they can seep into ground water. 87  -end thankyou 88