Nutrient pollution facts for kids

Nutrient pollution happens when too many "plant foods," called nutrients, get into our water. Think of it like giving a plant too much fertilizer – it can cause problems! These extra nutrients, especially nitrogen and phosphorus, make tiny water plants called algae grow super fast. This rapid growth is called eutrophication.

Where do these extra nutrients come from? They often wash off farms, flow from city streets, or come from untreated water from homes. Even pollution from burning fuels in cars and factories can add nutrients to the air, which then falls into water.

When there are too many nutrients, it can harm our environment. It can lead to big green messes of algae, make it hard for fish to breathe, and even cause acid rain. Luckily, we can help! Farmers can plant special areas around their fields to soak up extra nutrients. Cities can clean their water better before it goes into rivers. Everyone can help reduce this type of water pollution.

Where Do Extra Nutrients Come From?

Agriculture is a major source of nutrient pollution in the Gulf of Mexico. It also affects the Chesapeake Bay, along with city areas and air pollution.

Nutrients can wash off soil and fertilizer from farms during rain, like here in Tennessee.

Extra nutrients can enter our water from many places. The main sources depend on how the land is used nearby. We can group these sources into two types:

• Point sources: These are easy to identify, like a pipe directly releasing water from a factory or a wastewater treatment plant.
• Nonpoint sources: These are harder to pinpoint. They come from larger areas, like rain washing over many farm fields or city streets.

Farms and Fields

Farms use fertilizers to help crops grow. These fertilizers contain lots of nitrogen and phosphorus. If plants don't use all of it, rain can wash the extra nutrients into rivers and lakes. Animal waste from farms can also add many nutrients to the water.

Cities and Towns

In cities, rain washes over roads and parking lots, picking up pollutants and sometimes too much fertilizer from lawns. This "stormwater runoff" carries nutrients into drains and then into local waterways. Wastewater from homes and businesses, if not treated properly, also adds nutrients. Cars and factories release pollution into the air, which can fall as rain and carry nutrients into water.

Air Pollution

Sometimes, nutrients travel long distances through the air. Burning fossil fuels in power plants and vehicles releases nitrogen into the atmosphere. This nitrogen can then fall back to Earth with rain or snow, or as tiny particles, adding to water pollution far from the original source.

Key Nutrients: Nitrogen and Phosphorus

The two main nutrients causing problems are nitrogen and phosphorus.

• Nitrogen comes from man-made fertilizers, burning fuels, and animal waste. Too much nitrogen can cause many environmental issues.
• Phosphorus also comes from too much fertilizer and animal waste. When soil washes away, it can carry phosphorus into our waters. Wastewater treatment plants and some factories also release phosphorus.

How Nutrients Travel to Water

Nutrients don't just disappear; they move around!

• Staying in Soil: Some nutrients, especially phosphorus, can build up in the soil for many years. Eventually, rain can wash these stored nutrients into nearby water bodies.
• Washing Away (Runoff): Rain and melting snow can carry nutrients from farms, lawns, and streets into storm drains and rivers. This is called surface runoff. Farmers sometimes use more fertilizer than crops need, and the extra washes away.
• Falling from the Sky: Nitrogen can also travel through the air. When we burn fuels, nitrogen gases are released. These gases can then fall back to Earth with rain or snow, or as tiny dust particles. This is how acid rain can form and add nutrients to water.

What Happens When There Are Too Many Nutrients?

A harmful algal bloom in Western Lake Erie on July 9, 2018.

Too many nutrients in the water can cause many problems for nature and people.

Harm to Nature

• Algae Overgrowth: The biggest problem is often a huge increase in algae. These "algal blooms" can cover the water's surface, blocking sunlight from reaching plants below.
• Oxygen Loss: When these large amounts of algae die, they sink and are eaten by bacteria. This process uses up a lot of oxygen in the water. Without enough oxygen, fish and other aquatic animals can't breathe and may die. This is called hypoxia.
• Loss of Life: The lack of oxygen and sunlight can harm many different kinds of plants and animals, leading to a loss of biodiversity. It can also change the types of creatures that live in the water.
• Bad Smells and Toxins: Some algal blooms can produce bad smells and even harmful toxins. These toxins can be dangerous for animals and humans.

Impact on People and Money

• Unsafe Water: When water is full of algae and toxins, it costs more money to clean it for drinking.
• Fishing and Tourism: If fish die or water looks and smells bad, people stop fishing and visiting these areas. This hurts businesses that rely on fishing and tourism.
• Health Concerns: Drinking water with too much nitrate can be unsafe for babies, causing serious health problems. Swimming in water with harmful algae can cause skin rashes and breathing issues.

How Can We Reduce Nutrient Pollution?

We can all work together to reduce nutrient pollution and protect our water.

Smart Farming Practices

• Less Fertilizer: Farmers can use fertilizers more carefully, applying only what crops need. This saves money and reduces runoff.
• Buffer Zones: Planting strips of grass or trees along farm fields, called "buffer zones," helps soak up extra nutrients before they reach rivers.
• Artificial Wetlands: Creating special wetlands near farms can naturally filter out nutrients from runoff water.

Cleaner Cities and Homes

• Better Wastewater Treatment: Cities can improve how they clean wastewater from homes and businesses. This removes more nutrients before the water is released.
• Manage Stormwater: Cities can build systems to better manage stormwater runoff, preventing it from carrying pollutants into waterways.
• Reduce Air Pollution: Reducing pollution from cars and factories helps lessen the amount of nitrogen that falls into our waters from the sky.

What Countries Are Doing

Many countries are working to reduce nutrient pollution. They create rules and programs to help farmers and cities manage nutrients better. For example, in the United States, laws like the Clean Water Act help control pollution from factories and wastewater plants. They also encourage farmers to use practices that protect water quality. In places like the Chesapeake Bay, big plans have been put in place to reduce nitrogen, phosphorus, and sediment pollution. China is also working on similar issues, especially with pollution from cities and farms.

See also

• Agricultural wastewater treatment