Which parameter from water in ponds and lakes downwind of a coal-burning power plant would best indicate effects from the plant's emissions?

Which parameter from water in ponds and lakes downwind of a coal-burning power plant would best indicate effects from the plant's emissions?

• A. Temperature
• B. pH
• C. Turbidity
• D. Alkalinity

Answer: (B)

Emissions from coal-fired power plants release sulfur dioxide and nitrogen oxides that react in the atmosphere to form acids, which come down as acid rain. When this acid rain enters ponds and lakes, it lowers the water’s hydrogen ion concentration, decreasing pH and making the water more acidic. pH is the best indicator because it directly measures how acidic the water is, which is the immediate result of these emissions reaching the bodies of water. The other options don’t track the emissions’ chemical impact as directly: temperature might change due to heat discharge but doesn’t reflect acid deposition; turbidity indicates the amount of suspended particles and can vary for reasons unrelated to emissions; alkalinity shows how well water can buffer against acids but doesn’t itself show current acidity, and a high alkalinity can mask pH changes rather than reveal them.

Emissions from coal-fired power plants release sulfur dioxide and nitrogen oxides that react in the atmosphere to form acids, which come down as acid rain. When this acid rain enters ponds and lakes, it lowers the water’s hydrogen ion concentration, decreasing pH and making the water more acidic. pH is the best indicator because it directly measures how acidic the water is, which is the immediate result of these emissions reaching the bodies of water.

The other options don’t track the emissions’ chemical impact as directly: temperature might change due to heat discharge but doesn’t reflect acid deposition; turbidity indicates the amount of suspended particles and can vary for reasons unrelated to emissions; alkalinity shows how well water can buffer against acids but doesn’t itself show current acidity, and a high alkalinity can mask pH changes rather than reveal them.