AP Environmental Science Unit 7-8 Atmospheric, Terrestrial and Aquatic Pollution

Unit 7-8: Atmospheric, Terrestrial and Aquatic Pollution ● Types of Pollution ○ ○ ○ ○ ○ ○ ○ Noise Light Thermal Air Water Solid Waste Hazardous ● Biggest source of pollution ○ ○ ○ ○ ○ Burning fossil fuels Mining Industrial processes Deforestation Hazardous waste ● Anthropogenic Uses of Water ○ Agriculture ■ Water footprint - the total daily per capita use of freshwater ○ Agriculture is one of the most common uses of water. (70%) ○ Industry (20%) ○ Household Use (10%) ○ The United States is the country that uses the most water globally. ○ Different scenarios regarding geological differences ■ Eg. West v. East ○ China uses the least amount of water globally ● Irrigation - technological advances have made water use for crops more efficient. ○ Furrow - a trench that is flooded with water ○ Flood - the entire field is flooded with water ○ Spray - an apparatus sprays water across the field ○ Drip - a slow dripping hose is laid on or buried beneath the soil ● Hydroponic Agriculture ■ The cultivation of plants in greenhouse conditions by immersing roots in a nutrient-rich solution ○ An alternative to irrigation, hydroponic agriculture is more expensive but has several advantages ■ Requires little to no pesticide use ■ Uses up to 95% less water than traditional irrigation ■ Crops can be grown year-round ○ Water is also used for industrial processes and household use ■ After agriculture, the most common use of water is in industry ● Industry ○ Water is used mainly for: ■ Generating electricity ■ Cooling down systems ● Household Use (Anthropogenic Uses) ○ About 10% of water use in the U.S ■ Eg. Normal activities, recreational activities. ○ U.S is the leading user of water for households. ■ Advocacy for reduction in household use of water ○ Gray Water - wastewater from bath, showers, bathrooms and washing machine ○ Contaminated Water - wastewater from toilets, kitchen sinks and dishwashers. ● Wastewater From Humans + Livestock Could Pose Multiple Problems ○ Water Pollution - the contamination of streams, rivers, lakes, oceans or groundwater with substances produced through anthropogenic activities. Wastewater produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing laundry. ● Problems w. Wastewater ○ Oxygen depletion ○ Lack of nutrients ○ Disease-causing organisms + contaminants ● Oxygen Problems ○ Biochemical oxygen demand (BOD) - the amount of oxygen a quantity of water uses over a period of time at specific temperatures ○ Dead zone - an area w. Extremely low oxygen concentration + very little life ○ Anoxic - no oxygen present in an area. ● Excessive Nutrient Release ○ Eutrophication - a phenomenon which a body of water becomes rich in nutrients ○ Cultural eutrophication - an increase in fertility in a body of water; the result of anthropogenic inputs of nutrients ○ Eutrophication caused by an increase in nutrients ■ Eg. fertilizers ○ Eutrophication can cause rapid growth of algae which eventually dies causing the microbes to increase the BOD ● Disease-Causing Organisms ○ Wastewater can carry a variety of pathogens ■ Example of Diseases ● Cholera ● Typhoid ● Stomach Flu ● Diarrhea ● Hepatitis ○ Indicator species - a species that indicates whether or not disease-causing pathogens are likely to be tested ○ Fecal coliform bacteria - a group of generally harmless microorganisms in human intestines that can serve as an indicator species for potentially harmful microorganisms associated w. contaminated sewage. ● Wastewater Treatment ○ Septic Systems ■ Septic systems ■ Septic tank ■ Sludge ■ Septage ■ Leach field ○ Sewage Treatment Plants ■ In developed countries, municipalities use centralized sewage treatment plant that receive wastewater from hundreds or even thousands of households ■ In traditional waste treatment plants, there are two phases of treatment; primary and secondary ● Animal Feedlots and Manure Lagoons ○ Manure from concentrated animal feeding operations is a problem because of volume. It can also contain hormones and antibiotics that are given to the animals ■ Manure lagoons - human-made ponds lined with rubber built to handle large quantities of manure produced by livestock. ○ After the manure is broken down by bacteria\, it is spread onto fields as fertilizers ● Heavy Metals and Other Chemicals ○ Three Heavy Metals are of particular concern ■ Lead - found in pipes and other materials in older construction ■ Arsenic - occurs naturally and through human activity such as mining and industry ■ Mercury - occurs naturally and through human activity; primarily burning coal ● Deposition - acids deposited on Earth as rain or snow or as gases and particles that attach to the surface of plants, soil and water ○ Acid deposition occurs when burning coal releases sulfur dioxide and nitrogen dioxide into the air. ■ In the atmosphere, these chemicals are converted to sulfuric acid and nitric acid, which falls back to Earth as acid deposition ■ Acid deposition reduces the pH of water bodies to levels that are lethal to many organisms. ■ Many coal-burning facilities have installed coal scrubbers to combat this problem. ● Synthetic Organic Compounds and Human-Produced Chemicals ■ Synthetic compounds can enter the water supply from industrial point sources or from nonpoint sources when they are applied over large areas. ○ Compounds include pesticides, pharmaceuticals, military compounds and industrial compounds. ○ Synthetic organic compounds can be toxic, cause genetic effects and interfere with growth and sexual development. ● Military Compounds ○ Perchlorates - a group of harmful chemicals used for rocket fuel ■ Sometimes contaminates the soil in regions of the world where military rockets are manufactured, tested or dismantled. ● Industrial Compounds ○ Industrial compounds - chemicals used in manufacturing ■ It use to be common for manufacturers in the United States to dump industrial compounds directly into bodies of water ○ Polychlorinated biphenyls (PCBs) - a group of industrial compounds used to manufacture plastics and insulate electrical transformers and responsible for many environmental problems ● Oil Pollution ○ Petroleum products are highly toxic to many marine organisms, including birds, mammals and fish, as well as to the algae and microorganisms that form the base of the aquatic food chain ○ One source of oil in the water comes from drilling from undersea oil using offshore platforms ○ Oil and other petroleum products can also enter the oceans as spills from oil tankers ● Ways to Remediate Oil ○ Containment: Booms keep the floating oil from spreading, then boats equipped with giant oil vacuums suck up as much oil as possible ○ Chemicals: Chemicals break up the oil on the surface, making it disperse before it hits the shoreline ○ Bacteria: A particular bacterium consumes oil; scientists are currently trying to genetically engineer the bacterium to consume oil even faster. ● Non-chemical Water Pollution ○ Solid Waste Pollution ■ Solid Waste = Garbage + Sludge produced by sewage treatment plants ■ Garbage on beaches and in the ocean is dangerous to both marine organisms and people ■ In the United States the practice of dumping garbage in the ocean was curtailed in the early 1980s ■ The problem remains in many developing countries. ○ Sediment Pollution ■ 30% of all sediments in our waterways come from natural sources while 70% comes from human activities ■ Problems with sedimentation ■ Suspension of soil particles cause waterways to become brown and cloudy ■ Reduced infiltration of sunlight lowers productivity of aquatic plants and algae ■ Sediments clog gills and prevent aquatic organisms from obtaining oxygen ○ Thermal Pollution ■ Thermal Pollution - non-chemical water pollution that occurs when human activities cause a substantial change in the temperature of water ■ Thermal Shock - a dramatic change in water temperature that can kill organisms ■ One common solution is cooling towers that release the excess heat into the atmosphere instead of into the water. ○ Noise Pollution ● ● ● ● ■ Sounds emitted by ships and submarines can interfere with animal communication ■ Especially loud sonar can negatively affect species such as whales that rely on low-frequency, long distance communication. ■ An increased awareness of noise pollution in the ocean has inspired some shipbuilders to design ships equipped with quieter propellers Developed countries have addressed the problems of pollution by clearing up polluted areas and by passing legislation to prevent pollution in the future. Developing countries are still in the process of industrializing and are less able to afford water-quality improvements Developing countries suffer from the additional pollution but also benefit economically from the additional jobs and industrial spending, Air Pollution - the introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter an ecosystem ● Has many inputs and outputs ● Classifying Pollutants ○ Primary Pollutants = A polluting compound that comes directly out from its source (smokestack, exhaust pipe or natural emission sources) ● Examples - CO, CO2, SO2, NO2 and most suspended particulate matter ○ Secondary Pollutants = A primary pollutant that has undergone transformation in the presence of sunlight, water, oxygen or other compounds ● Examples - O2, sulfate and nitrate ■ Sulfur Dioxide (SO2) ● A corrosive gas that comes primarily from combustion of fuels such as coal and oil ● A respiratory irritant and can adversely affect plant tissue ● Releases in large quantities during volcanic eruptions and in much similar quantities during forest fires. ■ Nitrogen Oxides (NOx) ● Motor vehicles and stationary fossil fuel combustion are the primary anthropogenic sources of nitrogen oxides ● Respiratory irritant, increases susceptibility to respiratory infections ● An ozone precursor, leads to formation of photochemical smog ● Converts to nitric acid in atmosphere which is harmful to aquatic life and some vegetation ● Contributes to over-fertilizing terrestrial and aquatic systems ■ Carbon Oxides ● Carbon monoxide (CO) is a common emission in vehicle exhaust and most other combustion processes ● CO can be a significant component of air pollution in urban areas ● Carbon dioxide (CO2) released by burning fossil fuels has led to its becoming a major pollutant ● CO2 recently exceeded a concentration of 400 parts per million in the atmosphere and appears to be steadily increasing each year. ■ Particulate Matter - Solid or liquid particles suspended in air ● The sources of particulate matter and is affects ○ Particulate matter can be natural or anthropogenic ○ Particulate matter in the atmosphere ranges considerably in size and can absorb our scatter light, which creates a haze and reduces the amount of light ■ Haze - Reduces visibility ■ Photochemical oxidant - A class of air pollutants formed as a result of sunlight acting as compounds such as nitrogen oxides ■ Ozone - A secondary pollutant made up of three oxygen atoms bound together ■ Smog - A type of air pollution that is a mixture of oxidants and particulate matter ■ Photochemical Smog - A smog that is dominated by oxidants ■ Sulfurous smog - Smog dominated by sulfur dioxide and sulfate compounds ■ Lead ● A gasoline additive, also found in coal, oil, and old paint ● Impairs central nervous system ● All low concentrations can have measurable effects on learning and ability to concentrate ○ Volatile Organic Compounds (VOCS) - an organic compound that evaporates at typical atmospheric temperatures. ● Formed by evaporation of fuels, solvents, paints and improper combustion of fuels such as gasoline. ● A precursor to ozone formation. ○ Sources of Air Pollution ■ Natural emissions of pollution includes volcanoes, lightning, forest fires, and plants both living and dead; all releases compounds that can be classified as pollutants ■ Anthropogenic sources include on-road vehicles, power plants, industrial processes, and waste disposal (incinerator) ○ Anthropogenic Emissions ■ In the U.S, emissions from human activity are monitored, regulated and in many cases controlled. ■ Some anthropogenic sources are on-road vehicles, power plants, industrial processes, and incineration ■ The Clean Air Act and its various amendments require that EPA establish standards to control pollutants that are harmful to human health ■ Through the National Ambient Air Quality Standards the EPA periodically specifies concentration limits for each air pollutant. ● Photochemical Smog and Acid Rain ○ Photochemical smog in the United States ■ The formation of photochemical smog is complex and still not well understood. ■ A number of pollutants are involved and they undergo a series of of complex transformations in the atmosphere ■ Prevalent in Los Angeles, California, United States ● Pollution Control ■ Ways to address air pollution ● Avoid emissions in the first place ● Use cleaner fuel ● Increase efficiency ● Control pollutants after emissions ● Management of waste pollution ■ Ways of Controlling Emissions ● Remove sulfur dioxide from coal by fluidized bed combustion ● Install catalytic converter on cars ● Use baghouse filters ● Use electrostatic precipitators ● Install scrubbers in smokestacks ○ How People are Implementing Innovative Pollution Control Measures ■ Municipalities have tried a number of strategies ● Reduce gasoline spilled at the pump, restrict evaporation of drycleaning fluids, and the use of lighter fluid ● Reduce use of wood-burning stove and fireplace ● Limit automobiles to every other day uses or charge user fees for roads during heavy commute times. ● Breakdown of Stratospheric Ozone ■ When chlorine is present (from CFCs), it can attach to an oxygen atom in an ozone molecule to form chlorine monoxide (ClO) and O2 ● O3+Cl=ClO+O2 ■ The chlorine monoxide molecule reacts with a free oxygen atom which pull the oxygen from the CIO to produce free chlorine again ● ClO+O=Cl+O2 ■ A single chlorine atom can catalyze the breakdown of as many as 100,000 ozone molecules until finally one chlorine atom finds another and the process is stopped ■ In the process, the ozone molecules are no longer available to absorb incoming UV-B radiation ■ As a result, the UV-B can reach Earth’s surface and cause harm to biological organisms