Water Quality Quiz 2025 Update

Scientists are using pH levels and turbidity to determine the health of a water source for humans. Turbidity measures the cloudiness of water caused by suspended particles, and pH measures the level of acidity or alkalinity. The data table shows different turbidity and pH levels and the implications. Based on the table, which TWO conclusions about water are correct?

• Water with a pH of 9.5 and turbidity of 6 NTU is safe to drink.

• Water with a pH of 6.0 and turbidity of 0.9 NTU is safe to drink.

• Water with a pH of 7.5 and turbidity of 0.7 NTU is safe to drink.

• Water with a pH of 4.5 and turbidity of 7 NTU is unsafe to drink.

• Water with a pH of 7 and turbidity of 4.5 NTU is unsafe to drink.

How will a change in temperature affect the amount of dissolved oxygen in a body of water?

• A decrease in temperature will increase dissolved oxygen.

• An increase in temperature will increase dissolved oxygen.

• A decrease in temperature will not affect dissolved oxygen.

• An increase in temperature will not affect dissolved oxygen.

Which factor would most likely be examined to determine whether increased runoff was occurring into a body of water?

• pH

• turbidity

• bioindicators

• dissolved oxygen

Which happens to a body of water if there is too much nitrogen present?

• There is a decrease in turbidity.

• There is an increase of algal growth.

• There is an increase in dissolved oxygen.

• There is an increase in animal and plant diversity.

Why do biologists use indicator species?

• to compare freshwater and ocean ecosystems

• to count the number of organisms present

• to monitor water quality and biodiversity

• to analyze the dominant species

Which conditions are most suitable for aquatic organisms?

• high turbidity, low dissolved oxygen, basic pH, and high temperature

• low turbidity, low dissolved oxygen, neutral pH, and low temperature

• high turbidity, low dissolved oxygen, acidic pH, and high temperature

• low turbidity, high dissolved oxygen, neutral pH, and low temperature

The diagrams below show possible sources of water pollution. Which best describes diagrams 1 and 2?

• Diagram 1 shows point source pollution.

• Diagram 2 shows nonpoint source pollution.

• Both Diagrams 1 and 2 show point source pollution.

• Diagram 2 shows point source pollution, while diagram 1 shows nonpoint source pollution.

Which most likely makes fish excellent indicators of watershed health?

• Fish live only for a short period of time.

• Fish live in the water for at least a portion of their life.

• Fish differ in their tolerance to amount and types of pollution.

• Fish are frequently moving throughout different columns of water.

Which describes a bioindicator that would most likely help determine the health of a local pond?

• the appearance of an algae bloom

• the decrease in dissolved oxygen levels

• the rapid increase in water temperature

• the change in turbidity after heavy rainfall

Which is most likely caused by fertilizer being added to the water as the result of farm runoff?

• increased nitrate levels and algal blooms

• decreased phosphate levels and algal blooms

• decreased nitrate levels and decreased temperature

• increased phosphate levels and decreased temperature