Where’s the Water?
What percentage of Earth’s water is freshwater?
About 3%
What is point source pollution?
Pollution from a single, identifiable source
What nutrient pollutants commonly cause algal blooms?
Nitrogen and phosphorus
What term describes oxygen-depleted areas in water caused by pollution?
Disease, poisoning, or developmental problems
What process removes contaminants from wastewater before it is released?
Water treatment
Where is most of Earth’s freshwater stored?
In glaciers and ice caps
Give one example of nonpoint source pollution.
Agricultural runoff, urban runoff, or stormwater
What toxic metal is commonly associated with neurological damage when found in water?
Mercury
Name one human health risk linked to contaminated drinking water.
Disease, poisoning, or developmental problems
Name one way individuals can reduce water pollution.
Proper disposal, reducing fertilizer use, conserving water
Why do many regions experience water scarcity even though Earth has large amounts of water?
Most water is saltwater or frozen, and freshwater is unevenly distributed
Why is nonpoint source pollution harder to regulate than point source pollution?
It comes from many diffuse sources rather than one location
How do pesticides enter freshwater systems?
Through runoff or leaching from agricultural land
How does water pollution affect aquatic food webs?
Pollutants bioaccumulate and biomagnify
How do wastewater treatment plants help protect freshwater ecosystems?
They remove pollutants before water is released
How does climate influence freshwater availability in different regions of the world?
Climate affects precipitation, evaporation, and drought frequency
How can rainfall increase water pollution in urban areas?
Rain washes oil, trash, and chemicals into waterways
Why are microplastics a concern in aquatic ecosystems?
They are persistent, easily ingested, and can carry toxins
Why are children especially vulnerable to polluted drinking water?
Their bodies are still developing and absorb toxins more easily
Why are buffer zones along rivers effective at reducing pollution?
They filter runoff before it enters waterways
A country has abundant rainfall but still faces water shortages. Identify one human-related reason why this occurs.
Poor water management, pollution, overuse, or lack of infrastructure
A river downstream from farmland shows high nutrient levels. Identify the pollution type and explain the likely source.
Nonpoint source pollution from fertilizer runoff
A lake shows fish die-offs after a spike in algae growth. Identify the pollutant responsible and explain the chain reaction.
Excess nutrients → algal bloom → oxygen depletion
Explain how water pollution can affect communities economically, not just environmentally.
It harms fisheries, tourism, healthcare costs, and clean water access
A city wants to reduce pollution entering its river. Which solution would best address both point and nonpoint sources?
Improved wastewater treatment combined with green infrastructure