Question

8. Imagine a lake receives acid rain for an extended period of time. The original pH of the lake was 6, but it has now dropped to pH 3. How many times more acidic has this lake become? What negative impacts can this amount of acidification have on the environment?

Answer 1

8) According to chemists, pH can be referred as the negative log of Hydrogen ion concentration.

It helps to determine, how much a solution is acidic or basic by comparing it with the neutral pH, ie; pH of water which is 7.The pH ranges from 0 to 14, where, a value less than 7 indicates acidity and a pH greater than 7 shows the solution is alkaline.

Every single unit change in pH scale corresponds to a 10 fold change in hydrogen ion concentration.

For Eg: Taking hydrogen ion concentration at neutral pH 7 as 1; A pH of 6 indicates that the solution now contatins 10 times more hydrogen ions than that in pH 7( single unit change). Similarly change from pH7 to 5 shows 100 times more hydrogen ions (two unit change) and so on.

Therefore, dropping of pH from 6 to 3 shows that the lake now contains 1000 times more hydrogen ions ( a change of 3 units) as a result of Acid rain.

A decrease in this pH, ie an increase in Hydrogen ion concentration can have a huge negative impact on environment.

The impact that Acid rain have on aquatic environment is more obvious than any other eccosystem. Most organisms in aquatic habitats are sensitive to pH. The can only live a comfort life only in certain specific pH range. A change in pH can effect their normal living. It can directly kill them or it can make their eggs unable to hatch, in both ways contributing to the extinction of the pH sensitive organisms.

Another fact is that, all organisms in an eccosystem are interconnected. So, if any harm is caused to a partcular species it can effect the entire eccosystem in one way or the other (by disrupting food chains and food webs). This results in an ultimate loss of biodiversity of that particular eccosytsem and results in entire habitat destruction.

On the other hand, Acid rain when falls on soil, it effects the biodivesrity of soil organisms, plants and animal life also. It can even cause the death or drying of large trees. It can also remove the nutrients from soil that are essential for plant growth. Many elements like aluminium leeches to water bodies which may be toxic to quatic life in their eccess concentration. Ones the plant life strarts dropping, this can be reflected in the entire eccosystem. We know that plants are the primary producers and all organisms in tthe living world are dependent on them. This loss of plants, results in death of herbivores which subsequenlty effects higher life forms including humans.

So, infact Acid Rain can damage the entire eccosystem and making life impossible.