Air Pollution and Water

Chesapeake Bay (USA) is a site of much scientific study about water quality
Click on image for full size (67 Kb)
Courtesy of NOAA

Many people are aware of the fact that water can be contaminated from trash, oil spills, sewage, fertilizers, and chemicals from factories. Few realize that water can also be contaminated from air pollution in the atmosphere.

Several different types of air pollutants are able to enter lakes, streams, rivers, estuaries, and oceans. Some fall as dry particles due to gravity, while other air pollutants fall with rain, snow, or fog. They can enter a body of water directly, or they can fall onto land and enter indirectly with water run-off. Some of these pollutants are listed below. They not only harm water, but also the plant and animal life that depend on water to survive.

Nitrogen compounds

Nitrogen compounds supply an unnatural amount of nutrients to a body of water, which can cause a rapid increase in the growth of algae. This is called an algal bloom or “Red Tide.” Records of algal blooms exist from biblical times but they are becoming much more prevalent today. This overabundance of algae can clog waterways and upset the balance of the ecosystem. Some algal blooms are toxic, and since algae are at the base of the food web, their toxins can be transmitted to a wide variety of organisms. In addition to contributing to algal blooms, nitrogen pollution can also contribute to water bodies becoming more acidic.

Sulfur Dioxide and Nitrogen Oxides

Sulfur dioxide is created most often from industrial processes such as electrical utilities and the burning of fossil fuels. Similarly, the main source of nitrogen oxides is fossil fuel combustion. Both of these air pollutants dissolve in water vapor to form acid, and interact with other gases and particles in the air to form sulfates, nitric acid, and other chemicals that can be harmful to people and the environment. Dry deposits of these pollutants damage property, such as buildings, cars, and metal. Wet deposits refer to acidic rain, snow, and fog, commonly known as “acid rain,” which falls to Earth and eventually enters bodies of water making them more acidic. Areas with limestone rock tend to neutralize acid rain because limestone has a high pH. Bodies of water in areas such as the Northeastern United States and Eastern Canada are more vulnerable to acid rain because rock is primarily granite in both regions, which does not neutralize acid rain.

Acid rain causes a cascade of effects. Certain fish and animals, such as frogs, have a hard time adapting to and reproducing in an acidic environment. At pH 5, most fish eggs cannot hatch, and at lower pH levels some fish die. In fact, some acid lakes have no fish at all. Also, aluminum is released from soils into lakes and streams as acid rain flows through soils in a watershed. This aluminum is harmful to fish as well.

Mercury

Mercury occurs naturally in the environment. Approximately 2,700 to 6,000 tons of it are released into the atmosphere by gases released from the Earth’s crust and oceans each year. Another 2,000 to 3,000 tons are released each year into the atmosphere by human activities, primarily from burning wastes, and especially from fossil fuels such as coal. Mercury is soluble in water, where bacteria can cause chemical changes that transform it into methyl mercury, a more toxic form. Fish and shellfish can absorb methyl mercury, which in turn can impact fish-eating birds and mammals, including people. When these fish and shellfish are caught and cooked, most of the methyl mercury remains. The United States and other countries test to ensure that commercially sold fish is safe to eat. This is important because high levels of methyl mercury can cause nervous system damage or poisoning.

How can people reduce air pollution’s effect on water? Reducing our use of fossil fuels can make the biggest impact. Turn off lights. Walk, ride a bike, or use public transportation. Every little bit done by each person can add up to a noticeable improvement in air pollution.


Air Pollution's Effects on Us

Tragedy of the Commons

Air Pollution and Water

Chesapeake Bay (USA) is a site of much scientific study about water quality
Click on image for full size (67 Kb)
Courtesy of NOAA

Have you heard about rivers, lakes, or streams becoming polluted? Sometimes the pollution comes from trash, oil spills, sewage, fertilizers, or chemicals. However, sometimes the source of water pollution is in the air.

Air pollution can make its way into rivers, lakes, or streams. Several different types of air pollutants are able to waterways. Some fall from the sky as dry particles. Other air pollutants are carried to the ground in raindrops, snowflakes, or fog. Some of these pollutants are listed below. They not only harm water, but also the plant and animal life that depend on water to survive.

Nitrogen compounds
Nitrogen is a nutrient that plants need to grow. However, there can be too much of a good thing. Too much nitrogen in a body of water can cause algae to grow very quickly, clogging the waterways, and upsetting the balance of the ecosystem. This is called an algal bloom or “Red Tide.” Algal blooms happen more often now than they did hundreds of years ago. Some algal blooms are toxic. When animals eat the algae they also eat the toxins. Nitrogen compounds in air pollution are partly the cause of algal blooms, and can also contribute to water bodies becoming more acidic.

Sulfur Dioxide and Nitrogen Oxides
When fossil fuels are burned, sulfur dioxide and nitrogen oxides are released into the atmosphere. Both of these air pollutants dissolve in water vapor to form acid. The acidic water vapor condenses into clouds and falls eventually as precipitation such as rain or snow. This is known as “acid rain”. It falls to Earth and eventually enters bodies of water making them more acidic. That is a tough environment for some fish and animals, such as frogs, to survive and reproduce within. Acidic waters prevent fish eggs from hatching. In fact, some very acid lakes have no fish at all.

Some types of rocks neutralize acidic water. The acidic water dissolves rocks such as limestone. The limestone is then in the water, and makes the water less acidic. Bodies of water in areas such as the Northeastern United States and Eastern Canada are in more danger because rock is primarily granite, which does not neutralize acid rain.

Mercury
Mercury occurs naturally in the environment but it is also released into the atmosphere by people, mainly from burning waste, and especially from burning fossil fuels such as coal. Mercury can dissolve in water, where bacteria in the water transform it into poisonous methyl mercury. Fish and shellfish absorb methyl mercury into their bodies. When other animals, such as birds or people, eat the fish, the methyl mercury gets into their bodies as well. The United States and other countries test to ensure that the fish sold in stores are safe to eat.

How can people reduce air pollution’s effect on water? Reducing our use of fossil fuels can make the biggest impact. Turn off lights. Walk, ride a bike, or use public transportation. Every little bit done by each person can add up to a noticeable improvement in air pollution.


Air Pollution's Effects on Us

Tragedy of the Commons

Air Pollution and Water

Chesapeake Bay (USA) is a site of much scientific study about water quality
Click on image for full size (67 Kb)
Courtesy of NOAA

Have you heard about rivers, lakes, or streams becoming polluted? Sometimes the pollution is from trash or from dangerous things spilled into the water. However, sometimes the source of water pollution is in the air.

Air pollution can get into waterways too. Some air pollutants fall from the sky into water. Other air pollutants are carried to the ground in raindrops, snowflakes, or fog. Some of these pollutants are listed below.

Some types of air pollution can cause algae to grow very fast if they get into the water. The algae fill the waterways, leaving less space for other plants and animals. This is called an algal bloom or “Red Tide.” Because of pollution, algal blooms happen more often now than they did hundreds of years ago. Some algal blooms are toxic. When animals eat the algae they also eat the toxins.

When fossil fuels are burned, air pollution is released into the atmosphere. Some of the pollutants make the water in clouds change to be more acidic. The acidic water falls as rain, snow, or other types of precipitation. This is called “acid rain”. The acidic water gets into lakes, rivers, and other waterways making them acidic too. That is a tough environment for some fish and animals, such as frogs, to survive in. In fact, some very acid lakes have no fish at all.

People burning waste and fossil fuels such as coal release another air pollutant, called mercury, into the atmosphere. Mercury can dissolve in water. Bacteria in the water change it into a more poisonous form. Fish and shellfish absorb the poison into their bodies. When birds and people eat the fish, the poison gets into their bodies too. The United States and other countries test fish to make sure that the fish sold in stores are safe to eat.

How can people reduce air pollution’s effect on water? Reducing our use of fossil fuels can make the biggest impact. Turn off lights. Walk, ride a bike, or use public transportation. Every little bit done by each person can add up to a noticeable improvement in air pollution.


Air Pollution's Effects on Us

Tragedy of the Commons


Page created February 24, 2006 by Teri Eastburn. Last modified March 1, 2006 by Lisa Gardiner.
The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). © The Regents of the University of Michigan. All Rights Reserved. Site policies and disclaimer