The pH of healthy lakes is around 6.0. Due to acid rain, the pH of our lakes & rivers is decreasing. At low pH levels, producers such as phytoplankton cannot thrive. Decreased plankton can cause consumer populations to crash. The end result is a lake devoid of life. If the pH of an unhealthy lake is 4.0, explain why adding NaOH would not be a good compound to "de-acidify" the lake to a healthy pH."

Question

The pH of healthy lakes is around 6.0. Due to acid rain, the pH of our lakes & rivers is decreasing. At low pH levels, producers such as phytoplankton cannot thrive. Decreased plankton can cause consumer populations to crash. The end result is a lake devoid of life. If the pH of an unhealthy lake is 4.0, explain why adding NaOH would not be a good compound to "de-acidify" the lake to a healthy pH."

Well...such a change would be disruptive, but is there any specific scientific reason?

Thanks,
Lucy

Answer 1

what effect will all those sodium salts have on the flora and fauna in the lake?

Answer 2

Oh...I think I understand now.

Does this make sense?

Sodium hydroxide will react with the acids in the lake to form water and a salt.

Flora and fauna cannot thrive in a salty environment (from what I remember in biology class, osmosis draws out water from their cells). Therefore, adding sodium hydroxide would be harmful to these organisms living in the lake.

Answer 3

NaOH (sodium hydroxide) is a strong base and can neutralize acids by increasing the pH. However, using NaOH to de-acidify a lake to a healthy pH level is not a good solution for a few reasons:

1. Disruption of aquatic ecosystem: Adding NaOH directly to a lake would cause a sudden and drastic increase in pH. This rapid change in pH can have damaging effects on the aquatic ecosystem, as many organisms are highly sensitive to changes in their environment. It can lead to a shock to the system, potentially harming or killing various aquatic plants and animals.

2. Algae blooms: Elevated pH levels as a result of using NaOH can lead to an overgrowth of algae. Algae thrive in more alkaline conditions, and an excessive amount of algae can lead to harmful algal blooms. These blooms consume large amounts of oxygen, resulting in oxygen depletion in the water, which can further harm aquatic organisms.

3. Imbalance of other chemicals: Adding large amounts of NaOH to a lake can also disrupt the natural balance of other chemicals in the water. For example, it can react with dissolved carbon dioxide (CO2) in the water to form carbonate ions (CO3^2-). This reaction reduces the availability of CO2, which can have negative effects on aquatic plants and animals that rely on dissolved CO2 for survival.

4. Ecological implications: Manipulating the pH of a lake with NaOH can have far-reaching ecological implications that go beyond just addressing acidity. It may alter the composition and interactions of various species in the ecosystem, potentially leading to unintended consequences and disruptions to the food chain.

Instead of directly using NaOH, addressing the issue of acidification in lakes and rivers requires a more comprehensive and balanced approach. This can involve minimizing the emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx), which are primary contributors to acid rain. Additionally, implementing conservation strategies to protect and restore natural buffers, such as wetlands and forests, can help mitigate the effects of acid rain and preserve the health of lakes and rivers.