Chapter 7 Lesson 2 Impacts on Land
Using Land Resources 3 uses that change the land are agriculture, development, and mining. Less than 1/3 of Earth can be farmed. New farmland must be created for the growing populations. Development is the construction of buildings, roads, bridges, dams and other structures.
Forest Resources Deforestation – removing large areas of forests for human purposes. Caused by demand for wood products, need for space, farmland, housing, need for space, farmland, housing, roads, highways, fuel, grazing. roads, highways, fuel, grazing. Deforestation cause: –Force animals and plants into confined areas –Can lead to extinction of organisms –Affect soil quality –Increase in CO 2 in the atmosphere
Agriculture and Nitrogen Cycle Farmers add fertilizers that contain nitrogen to soil to increase crop yield Living things use to make proteins As living things die, decompose or produce waste they release nitrogen into both the soil and atmosphere Nitrogen gas makes up ~79% of the atmosphere (non usable)
Agriculture and Nitrogen Cycle Nitrogen has to be converted from gas to usable forms: –Bacteria –Nitrogen Converted Fertilizer If nitrogen is not converted it could contaminate: –Water –Soil –Plants –Organisms in our waters
Agriculture and Nitrogen Cycle
Mining Mining is the removal of nonrenewable resources such as iron, copper, and coal from the land. Strip mining removes a strip of land to obtain minerals, and then replacing the strip. This exposes the soil and can be washed or blown away. These areas can remain barren for years before they are rich enough to support the growth of new plants.
Protecting the Soil Poor soil management can result in 3 problems: erosion, nutrient depletion, and desertification.
Nutrient Depletion Nutrient Depletion: When farmers plant the same crops in a field year after year. As a result, the plants use more nutrients than the decomposers can replace. The soil becomes less fertile.
Desertification The advance of desertlike conditions into areas that previously were fertile. Overfarming Overgrazing
Urban Sprawl Urban Sprawl: development of houses and other buildings near a city.
Restoring the Land Land Reclamation: The process of restoring an area of land to a more natural, productive state. Smooth and replace strip mines with new topsoil. Plant grass.
Section 2 Solid Waste Every hour people throw away 2.5 million plastic bottles. Every year people throw away enough white paper to build a wall 4 meters high that stretches coast to coast. Every year people throw away 1.6 billion pens, 2.9 million tons of paper towels, and 220 million automobile tires.
Problem of Waste Disposal Municipal solid waste : Waste materials produced in homes, businesses, schools, and other places in a community.
Three methods of handling solid waste. You can bury it, burn it, or recycle waste. Leachate: Polluted liquid, from the rainwater that has dissolved chemicals from the waste. Sanitary Landfills: Holds municipal solid wastes, construction debris, and some types of agricultural and industrial waste.
Incineration TTTThe burning of solid waste is called incineration. TTTThe advantages of incinerators is that they do not take up as much space as landfills, they do not pose the risk of polluting groundwater, and the heat they produce can generate electricity. DDDDisadvantage is that they are more expensive to build.
Recycling Recycling: The process of reclaiming raw materials and reusing them. Biodegradable: A substance that can be broken down and recycled by bacteria and other decomposers. Most recycling focuses on 4 major categories of products: metal, glass, paper, and plastic.
Products to Recycle
Metal Metals such as iron and aluminum can be melted and reused. Recycling metal saves money and causes less pollution than making new metal.
Glass Glass is one of the easiest products to recycle because it can be melted down over and over to make new glass containers. Recycling glass is less expensive than making glass from raw materials. Less energy is required. It also reduces the environmental damage caused by mining for sand, and limestone.
Paper Most paper products can only be recycled a few times. Each time the paper is recycled to make pulp, the new paper is rougher, weaker, and darker. It takes about 17 trees to make one metric ton of paper.
Plastics When oil is refined to make gasoline and other petroleum products, solid materials called resins are left over. These resins can be heated, stretched, and molded into plastic products. Numbers are found on the bottom of plastic containers. The numbers 1 & 2 are made from plastics that are often recycled.
What Can You Do? These are sometimes called the 3 R’s – Reduce, Reuse and Recycle. Reduce: Refers to creating less waste in the first place. (Use cloth shopping bags than disposable paper or plastic bags.) Reuse: Find another use for the object rather than discarding it. (Example ???) Recycle: Reclaiming raw materials to create new products.
Composting Composting: Is the process of helping the natural decomposition processes break down many forms of waste. Compost is an excellent natural fertilizer for plants. Examples: (Raked leaves, grass, food waste, eggshells, coffee grounds and cow manure)
Section 3 Hazardous Wastes Hazardous wastes are classified into 4 categories: Toxic, Explosive, Flammable, and Corrosive.
Toxic Waste Are poisonous wastes that can damage the health of humans and other organisms.
Explosive Waste Are waste that react very quickly when exposed to air or water, or that explode when they are dropped.
Flammable Waste Are waste that catch fire easily and can begin burning at fairly low temperatures.
Corrosive Waste Are waste that dissolve or eat through many materials.
Radioactive Waste Are waste that contain unstable atoms. They require special disposal.
Health Effects Short-term exposure to hazardous wastes, may cause irritation or more severe health problems. Long-term exposure to hazardous wastes, may cause diseases, such as cancer, and may damage body organs, including the brain, liver, kidneys, and lungs.
Disposal of Hazardous Waste Methods of hazardous waste disposal include burial in landfills, incineration, and breakdown by living organisms. Another method involves storing liquid wastes in deep rock layers. Scientists have not been able to develop completely safe methods for disposing of radioactive waste.