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Human Impacts: Pollution — Reading Comprehension

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MS-LS2-4
MS-ESS3-3

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This middle school science reading passage, aligned with NGSS standards MS-LS2-4 and MS-ESS3-3, examines the mechanisms and effects of human-caused pollution on ecosystems. Students will learn how water pollution from agricultural runoff, industrial waste, sewage, and plastic affects aquatic environments, leading to phenomena like eutrophication and dead zones. The text also covers air pollution, including acid rain and smog, and highlights soil contamination from pesticides and heavy metals. The concept of plastic pollution, including ocean gyres and microplastics, is explored, as well as the processes of bioaccumulation and biomagnification. The passage integrates scientific thinking, cause-and-effect relationships, and real-world implications, making it ideal for grades 6-8. Activities include comprehension questions, writing prompts, and graphic organizers, with audio integration for accessibility. This resource supports science literacy and critical thinking about environmental issues.

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environment, industry, industrial smoke, smog, smoke, steam, air pollution, evening sky, air pollution, air pollution, air pollution, air pollution, air pollution — Burning fossil fuels produces pollutants like sulfur dioxide and nitrogen oxides. Image by shogun /
Source: Pixabay.

Pollution is a major force changing ecosystems on Earth today. Scientists observe that rivers, oceans, forests, and even the air we breathe are increasingly affected by human activities. From algae-covered lakes to smog-filled cities, the evidence shows that pollution disrupts the balance of natural systems. This passage explores how different types of pollution interact with living and nonliving parts of ecosystems, leading to complex environmental problems.

Water Pollution and Eutrophication

Water pollution occurs when harmful substances enter bodies of water. Common sources include agricultural runoff containing fertilizers and pesticides, industrial discharge, untreated sewage, and plastic waste. When excess nutrients like nitrogen and phosphorus flow into lakes and rivers, they trigger a process called eutrophication. This causes rapid growth of algae, known as algal blooms. As algae die and decompose, they use up oxygen in the water, creating dead zones where fish and other aquatic life cannot survive. For example, the Gulf of Mexico’s dead zone sometimes covers over 15,000 square kilometers due to nutrient runoff. Plastic pollution also threatens aquatic life, as animals can ingest or become entangled in debris, and tiny microplastics enter food webs.

Air and Soil Pollution: Interactions and Effects

Air pollution results from the release of gases and particles into the atmosphere. Burning fossil fuels produces pollutants like sulfur dioxide and nitrogen oxides, which combine with water vapor to form acid rain. Acid rain damages forests, harms aquatic ecosystems, and erodes buildings. Smog, a mixture of pollutants, reduces air quality and affects the health of both plants and animals. Meanwhile, soil contamination can occur when pesticides, heavy metals, or industrial waste seep into the ground. These toxins can be absorbed by plants and enter food chains. Through processes called bioaccumulation and biomagnification, toxins become more concentrated at each step up the food chain, threatening top predators and even humans who consume contaminated food.

Plastic Pollution and Global Impacts

Plastic pollution is a global concern, especially in the world’s oceans. Large collections of floating plastic, called ocean gyres, trap debris far from land. Over time, plastics break down into microplastics, which are difficult to remove and are found in fish, birds, and even human food. Research shows that more than 8 million tons of plastic enter the oceans each year. The health impacts of microplastics are still being studied, but their widespread presence highlights the need for better waste management and pollution prevention strategies.

Pollution is a complex problem that affects every part of the environment. Understanding its causes, mechanisms, and effects is essential for developing solutions. By reducing pollution and promoting sustainable practices, we can help protect ecosystems for future generations.

Interesting Fact: Scientists have discovered microplastics in Arctic ice and in the deepest ocean trenches, showing that plastic pollution reaches even the most remote places on Earth.

What is eutrophication?

A process where water becomes too rich in nutrients, causing excessive algae growth and oxygen loss.The increase of plastic in the oceans.Release of gases into the atmosphere from cars and factories.Plants absorbing sunlight to make food.

Which of the following is a result of algal blooms?

Dead zones with low oxygen.Increased plant diversity.Cleaner water for fish.Faster river currents.

According to the passage, how does acid rain form?

When pollutants from burning fossil fuels combine with water vapor.When plastics break down in the ocean.When fertilizers are added to the soil.When algae decompose in lakes.

What is the main reason microplastics are a problem in the ocean?

They are hard to remove and enter food chains.They make water taste salty.They help fish grow faster.They clean the water.

What is meant by 'biomagnification' in the context of pollution?

The increase in concentration of toxins higher up the food chain.The process of breaking plastics into smaller pieces.The removal of pollutants from water.The growth of algae due to extra nutrients.

What does 'dead zone' mean as used in the passage?

An area in water with very low oxygen where few organisms survive.A place where no plants can grow.A polluted city with lots of smog.A dry area with no rainfall.

If acid rain increases, what could happen to forests?

Trees and plants may be damaged or killed.There will be more animal life.Soil will become richer in nutrients.Nothing will change.

If plastic pollution continues to increase, what is a likely effect on ocean life?

More animals will ingest plastic or become entangled, harming food chains.Ocean life will thrive more than before.Fish populations will increase rapidly.Plastic will disappear on its own.

Bioaccumulation means that toxins build up in living things over time. (True/False)

TrueFalse

Pollution only affects water, not air or soil. (True/False)

FalseTrue