ACID PRECIPITATION CHAPTER 12 SESCTION 3

Students understand that Human decisions and activities have had a profound impact on the physical and living environment.

Things to Ponder Humans have negatively impacted the environment by (1) Habitat destruction (urban sprawl) (2) Importation of invasive species (3) Pollution (4) Human population growth (5) Overexploitation: HIPPO Humans have positively influenced the environment by (1) Conservation laws and policies (2) biological controls (3) agricultural practices (4) reducing waste (5) using alternative renewable sources of energy. Evidence of problems in my community affects all living things on Earth. Global warming, ozone depletion, and acid precipitation are examples of how we have had a global impact on the environment.  

Objectives Students will know The causes of acid precipitation How acid precipitation affects plants, soils, aquatic ecosystems and humans. How countries are working together to solve the problem of acid precipitation.

LEARNING ACTIVITIES Quick lab Neutralizing Acid Precipitation Procedure Pour ½ Tbsp of vinegar into one cup of distilled water, and stir the mixture well. Check the mixture by using pH paper. Crush one stick of blackboard chalk into a powder. Pour the powder into the vinegar and water mixture. Check the pH of the mixture. Analysis Did the vinegar and water mixture become more or less acidic after the powdered chalk was poured in? what did you learn from this experiment?

Acid precipitation lab To study the effect of sulfur dioxide on the growth of seedling.

Can you explain? Pollutants introduced into the atmosphere can also damage automobiles?

Video on coal combustion and acid precipitation http://www.youtube.com/watch?v=HE6Y0iEuXMQ Acid precipitation is precipitation such as sleet, rain, or snow that contains a high concentration of acids. When fossil fuels are burned, they release oxides of sulfur and nitrogen. When the oxides combine with water in the atmosphere, they form sulfuric acid, nitric acid, which fall as acid precipitation. This acidic water flows over and through the ground, and into lakes, rivers, and streams. Acid precipitation can kill living organisms, and can result in the decline or loss of some local animal and plant populations.

The pH scale A pH (power of Hydrogen) number is a measure of how acidic or basic a substance is. Lower the pH number is, the more acidic a substance is. Pure water has a pH of 7.0. Normal precipitation is slightly acidic, because atmospheric carbon dioxide dissolves into the precipitation and forms carbonic acid. Normal precipitation has a pH of about 5.6. precipitation is considered acidic if it has a pH of less than 5.0. The most acidic precipitation in North America occurs around Lake Erie and Lake Ontario.

Acid Rain

EFFECT OF ACID PRECIPITATION ON SOILS AND PLANTS Acid precipitation can cause a drop in the pH of soil and water. This increase in the concentration of acid is called acidification. When the acidity increases, some nutrients are dissolved and washed away by rain water. Increased acidity causes aluminum and other toxic metals to be released and possibly absorbed by roots of plants. Aluminum can cause root damage. Sulfur dioxide in water vapor clogs the openings on the surface of plants.

Harmful effects of acid precipitation on plants

ACID PRECIPITATION AND AQUATIC ECOSYSTEMS If acid precipitation falls on a lake and changes the water’s pH, acid can kill aquatic plants, fish and other aquatic animals. Acid precipitation causes aluminum to leach out of the soil surrounding a lake. The aluminum accumulates in the gills of fish and interferes with oxygen and salt exchange. As a result fish are slowly suffocated.

Acid shock The effects of acid precipitation are worst during in the spring, when the acidic snow that accumulated in the winter melts and rushes into lakes and other bodies of water. This sudden influx of acidic water that causes a rapid change in water’s pH is called acid shock. This causes a large number of fish in a population to die as you can see in the picture below. Acid shock also affects the reproduction of fish and amphibians. They produce fewer eggs, and these eggs often do not hatch. The offspring that do survive often have birth defects and cannot reproduce.

Do You think this will happen at the current rate of increase in automobiles?

CONTROL MEASURES To counteract the effects of acid precipitation on aquatic ecosystems, some states in the United States and some countries spray powdered limestone on acidified lakes in the spring to help restore the natural pH of the water.  

ACID PRECIPITATION AND HUMANS Toxic metals such as aluminum and mercury can be released into the environment when soil acidity increases. Theses toxic metals find their way into crops, water, and fish. The toxins then poison the human body. Research has shown that there may be a correlation between large amounts of acid precipitation received by a community and an increase in respiratory problems in the community’s children. The standard of living of some people is affected by acid precipitation. Decrease in numbers of fish caused by the acidification of lakes and streams can influence the livelihood of commercial fisherman and people involved in the sport-fishing industry.

- Forestry is also affected when trees are damaged by acid precipitation. Acid precipitation can dissolve the calcium carbonate in common building materials, such as concrete and limestone. Some of the world’s most important and historic monuments like those made of marble, are being affected by acid precipitation. For example sulfur dioxide has caused black crusts to form on the carbonate stones of historic Greek monuments.

INTERNATIONAL CONFLICTS AND COOPERATION One problem in controlling acid precipitation is that pollutants may be released in one geographic area and fall to the ground hundreds of kilometers away. In the spirit of cooperation Canada and the United States signed the Canada- U.S. Air quality Agreement in 1991. Both countries agreed to reduce acidic emissions that flowed across the Canada-U.S boundary.

What can you do as an individual? Turn off lights, computers, and other appliances when you're not using them. Use energy-efficient appliances: lighting, air conditioners, heaters, refrigerators, washing machines, etc Only use electric appliances when you need them. Keep your thermostat at 68°F in the winter and 72°F in the summer. You can turn it even lower in the winter and higher in the summer when you are away from home. Insulate your home as best you can. Carpool, use public transportation, or better yet, walk or bicycle whenever possible Buy vehicles with low NOx emissions, and properly maintain your vehicle.

Useful link   http://www.epa.gov/acidrain/education/site_students/acid_anim.html Acid precipitation video Source Environmental Science By Karen Arms and image from internet http://faculty.plattsburgh.edu/thomas.wolosz/acid_rain.htm Effects of acid precipitation http://geography.about.com/od/globalproblemsandissues/a/acidrain.htm Cause, effects and solution http://epa.gov/acidrain/education/site_students/whatcanyoudo.html What can you do to make a difference http://www.epa.gov/acidrain/reducing/index.html#take