Environmental Science Chapter 5 Mr. Walker Water Notes Environmental Science Chapter 5 Mr. Walker

Freshwater Cont. -Water is essential for life. Water is a renewable resource and can be used over and over again. The water we drink has been around for billions of years and may have been used by other organisms or as a cloud or part of the ocean. Only 3 % of water on earth is freshwater, 77% of that is stored in polar icecaps. -Watershed: The entire area of land that is drained by a river. -We use freshwater for drinking, irrigation, growing crops etc. Two sources Groundwater and surface water. -Surface Water: Fresh water that is above ground in lakes, ponds, rivers, and streams. -Dams: a structure built across a river or stream that restricts the flow of water traveling downstream collects behind the dam a forms a reservoir. -Groundwater: Water that seeps underground through the soil. Examples include aquifers. -Aquifer: A large quantity of groundwater found in underground rock formations. -Recharge zone: The area of land from which the groundwater originates.

Aquifers: Snake River Aquifer Large amounts of groundwater are found in underground rock formations called Aquifers. Aquifers usually consist of rocks, sand, and gravel with a lot of air spaces in which water can accumulate. Aquifers continuously receive water that percolates down from the surface but this process is very slow. It can take millions of years for an aquifer to form. The area of land from which the groundwater originates is called its recharge zone. In Idaho Falls, we are on top of the Eastern Snake River Aquifer. Like many aquifers ours is running low. People are pumping out the water faster than it can be replaced naturally.

Water Conservation and Usage Water goes around and comes around, but its passage through the water cycle still takes time. Water is limited so people must use it wisely. More people are installing low-flow faucets and toilets. Many people water their lawns at night and replacing grass lawns with native plants which don’t use as much water.

Water Conservation and Usage -Desalinization: The removal of salt from salt water. There are two methods: distillation and reverse osmosis. -Distillation: Heat is used to evaporate fresh water from salt water, leaving the salts behind. -Reverse Osmosis: Pressure is used to push water through a semipermeable membrane that will not permit the salts to pass.

Types of Freshwater Pollution -Point pollution: Pollution that is discharged from a single source, such as factory, a wastewater treatment plant, or an oil tanker. -Nonpoint pollution: Comes from many sources rather than a single specific site.

Freshwater Pollution: -Water pollution: The introduction of chemical, physical, or biological agents into the water that degrades the quality of the water and affects the organisms that depend on it. There are typically two causes: Industrialization and human population explosion. Both produce waste products that cannot be disposed of as fast as they are produced. Pathogens: Disease-causing organisms such as bacteria. Pollution occurs when human sewage is untreated or enters water through storm sewers, and when animal feces wash off the land into water Organic Matter: Biodegradable remains of animals and plants, including feces. These come primarily from nonpoint sources. Organic Chemicals: Pesticides, fertilizers, plastics, detergents, gasoline and oil, and other materials made from fossil fuels such as petroleum. (Petroleum consists of hydrocarbons originally found in ancient plants.) Mostly non-point source pollution. Inorganic chemicals: Acids, salts, toxic metals; from both point and nonpoint sources. Toxic chemicals: chemicals that are poisonous to living things, including heavy metals (lead, mercury, cadmium), many industrial chemicals, and some household chemicals. Physical agents: Heat and suspended solids, such as soil. Radioactive waste: From power plants or nuclear processing and defense facilities. -Wastewater: Most of the water that goes down the drain.

How Water Pollution Affects Ecosystems -Biological magnification: Also known as biological accumulation. Each organism stores toxins in its tissues, so each feeding step along the food chain allows those toxins to be passed onto the next “eater” increases. This increase is called biological magnification. -Eutrophication: An abundance of nutrients in a water ecosystem. It can occur naturally over time as organism die and decompose, adding nutrients to the water. -Artificial eutrophication: Human caused eutrophication by adding inorganic plant nutrients, such a phosphorus and nitrogen, get into the water from sewer and fertilizer runoff. -Thermal Pollution: When excessive amounts of heat are added to a body of water. This can occur when powerplants or other industries located along lakes or rivers use the water to circulate around engines to absorb waste heat. The warm water is then returned to the lake or river creating an unnatural warm area.

Air Pollution -Air Pollution: When harmful substances end up in the air at unhealthy levels. -Primary Pollutant: A pollutant that is put directly into the air by human activity. -Secondary Pollutant: These are formed when a primary pollutant comes into contact with other primary pollutants, or even with naturally occurring substances like water vapor and a chemical reaction takes place. An example of a secondary pollutant is ozone. -Ozone: Forms when oxygen in the air reacts with VOC’s (volatile organic compounds) and other air pollutants from trucks, cars, and natural sources in the presence of the sun’s ultraviolet rays.

Air Pollution Cont. -Industrial air pollution: Industries and power plants that generate electricity must burn fuel to get the energy they need. In most instances, this is a fossil fuel. The burning of fossil fuels causes huge quantities of oxides to be released into the air. -Thermal inversions: Normally, air temperatures decrease with height, but in thermal inversion, the air above is warmer than the air below. -Smog: Air pollution hangs over urban areas and reduces visibility. It results from chemical reactions involving sunlight, nitrogen oxides, and hydrocarbons.

Acid Precipitation in Ecosystems -Acid precipitation: Highly acidic precipitation (rain, sleet, snow) that results from the burning of fossil fuels. Typically it has a pH of less than 5.6. -Acid Shock: Occurs the most in the spring when acidic snow melts and rushes into lakes and other bodies of water. This is a sudden influx of acid water which can wipe out entire populations of fish and amphibians. -ph Scale: A pH number is a measure of how acidic or basic a substance is. 7 is considered neutral. Above 7 becomes more basic and below 7 becomes more acidic.