Deadly Rain in the Adirondacks

Bordallo, M. C. A. (2010). Real-life cases for teaching and learning environmental chemistry.

Unpublished manuscript. Page 1

CASE 1

INSTRUCTIONS

1. Read “Deadly Rain in the Adirondacks” , Background and Problem. 2. Answer questions 1-6 in the worksheet individually. 3. Discuss and answer questions 7-8 with your group mates.

DEADLY RAIN IN THE ADIRONDACKS

In 1961, Major Bowes bought the Covewood Lodge, located on the banks of Big Moose Lake in Adirondacks State Park in upstate New York.

More than 60 years later, Major Bowes still loves the beauty of the area, even as

he has watched how acid rain has damaged the trees, killed the fish and harmed the drinking water.

“It’s very disturbing because we are wrecking the planet,” he said. “The lake looks just as pretty as it ever did, but it’s different...The acidified water would corrode the pipes and lead and copper would get into the water. Now, we treat the water with calcium carbonate and UV light to keep it pure.”

The Adirondack State Park is the largest state park in the United States, spanning 2.5 million hectares of lakes, forest and mountains. In the late 1970s and early 1980s, scientists noticed freshwater fish dying in remote lakes and streams in the Adirondacks.

“Particularly, brook trout began disappearing from lakes that historically had important recreation fisheries,” Cornell University research associate Dan Josephson



said.

Acid rain in the Adirondacks is caused primarily by emissions from coal power plants in the Midwest that travel through prevailing winds into the Adirondacks.

The Clean Air Act of 1990 set tough restrictions on the amount of smokestack emissions of sulphur dioxide and nitrogen oxides, which react with water to form sulfuric acid and nitric acid, respectively. But by the time the act was passed, 352 of the Adirondacks’ 1,460 lakes had been declared dead.

The Clean Air Act resulted in the reduction of sulphur dioxide emissions by as

much as 10 tonnes. But while sulfur levels have declined substantially in many of the waterways of the Adirondacks, nitrogen levels have continued to rise in nearly half of them. Research has shown that even as 15 of the lakes had improved, there was an increase in the percentage of acidified lakes from 45 to 51 percent since the early 1990s.

In June 2008, scientists published data that suggests soils in the Adirondacks are steadily increasing in acidity.

“Soils were once believed not sensitive to acid rain,” said Charles Driscoll, author of Acid Rain in the Adirondacks. “New studies show they are continuing to acidify. There is evidence that soil acidity, which strips calcium and magnesium, is jeopardising tree species like red spruce and sugar maple. Acid rain may have gone off the radar but the problem persists.”

BACKGROUND Normal rainfall has a slightly acidic pH of 5.6 because rain reacts with the carbon dioxide in the atmosphere to form carbonic acid. Acid rain is defined as rain having a pH less than 5.6. So what is pH? pH is a measure of the degree of acidity or basicity of a solution. It is a measure of how much hydrogen ion is in solution. It is defined by the following equation:

pH = - log [H+], where [H+] = hydrogen ion concentration

According to the Bronsted-Lowry Theory, an acid is a proton donor while a base is a proton acceptor. Acidic solutions have higher concentrations of hydrogen ions than basic solutions. Thus, from the equation of pH, the more acidic a solution is, the lower its pH. Conversely, the more basic a solution is, the higher its pH. The pH scale lies mainly in the range 0 to 14. The neutral point on the scale is 7. Values below 7 indicate increasing acidity and those above 7 indicate increasing basicity.



Air pollution from the burning of fossil fuels is the major cause of acid rain. Sulfur dioxide (SO2) from burning high-sulfur coal in power plants and metal smelters, and nitrogen dioxide (NO2) and nitric oxide (NO) from automobile emissions react with water vapor in the atmosphere to produce sulfuric acid (H2SO4) and nitric acid (HNO3), respectively (Fig. 1).

Some acid rain is also due to natural pollutants. Volcanoes emit sulfur oxides and

sulfuric acid, and lightning produces nitrogen oxides and nitric acid.

Fig. 1. Formation of Acid Rain Source: Dowdey, Sarah. "How Acid Rain Works." 05 August 2007. HowStuffWorks.com. <http://science.howstuffworks.com/acid-rain.htm> 08 January 2010.

PROBLEM

How may acid rain and its effects be reduced?



REFERENCES

Handelman, D. (2009, April 19). A deadly rain: Clean-air laws' impact on acid rain has limited effect on Adirondack lakes. The Online Leader. Retrieved January 10, 2010, from http://www.the-leader.com/state_news/x1098183276/A-deadly-rain-Clean-air-laws-impact-on-acid-rain-has-limited-effect-on-Adirondack-lakes

Hill, J. W. and Kolb, D. K. (2004). Chemistry for changing times. New Jersey:

Pearson Prentice Hall.

Thomas, L. G. (2008, June 25). Acid rain threatens Adirondacks. Protect the Adirondacks. Retrieved January 9, 2010 from http://www.protectadks.org/data/content/view/248/127/

http://www.the-leader.com/state_news/x1098183276/A-deadly-rain-Clean-air-laws-impact-on-acid-rain-has-limited-effect-on-Adirondack-lakes

http://www.the-leader.com/state_news/x1098183276/A-deadly-rain-Clean-air-laws-impact-on-acid-rain-has-limited-effect-on-Adirondack-lakes

http://www.protectadks.org/data/content/view/248/127/



WORKSHEET

NAME _______________________________ DATE _____________

SECTION ______________

DEADLY RAIN IN THE ADIRONDACKS

1. Define the following:

A) Acid

B) Base

C) pH

D) Acid rain

2. What is the main source of acid rain in the Adirondacks?

3. Aside from the main source of acid rain in the Adirondacks, what are other man-

made and natural sources / causes of acid rain?



4. Write the balanced chemical equations for the following reactions involved in the

formation of nitric acid (HNO3):

A) Nitric oxide and molecular oxygen react to produce nitrogen dioxide.

B) Nitrogen dioxide reacts with water to produce nitric acid and nitric oxide.

5. Write the balanced chemical equations for the following reactions involved in the

formation of sulfuric acid (H2SO4):

A) Sulfur reacts with molecular oxygen to produce sulfur dioxide.

B) Sulfur dioxide reacts with molecular oxygen to produce sulfur trioxide.

C) Sulfur trioxide reacts with water to produce sulfuric acid.



6. What are the effects of acid rain?

7. Why was it more difficult to control the levels of nitrogen than those of sulfur in

the air?

8. What solutions do you propose to lessen the impact of acid rain in the

Adirondacks?

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Deadly Rain in the Adirondacks