Question

A water body has high BOD indicating that water is
A. Being contaminated with sewage
B. Being aerated
C. Receiving minerals
D. Atrophic

Answer 1

Hint: It is the measure of the amount of perishable or decaying organic matter present in water with microflora. In addition, the more of the water is polluted by microflora or degradable material present in water, the more oxygen will be required and higher will be the BOD of water and vice versa.

Step by step answer:The levels of BOD of water bodies are measured for various studies or research purposes. By measuring the BOD of water one can know the purity of the water sample. And also the type of microflora and biodegradable material present in water can be known by measuring the BOD of water.
-Option A states that the high BOD level will indicate its level of purity or contamination. The sewage waste mostly contains putrescible organic matter and vast populations of microbes. Thus, it contaminates the water and increases the oxygen demand due to a large number of microbes present in it.
-Option B states that the water body with higher BOD will be aerated but that is not the case. It is the opposite in the water samples having high BOD levels. Being aerated means having sufficient air or oxygen levels, but higher BOD indicates depleted air or oxygen levels.
-Option C says that the water body will be receiving minerals if it has high BOD. But high BOD is indicative of high contamination of water means that water will have lethal substances but not minerals.
-Option D is irrelevant as it has no connection with the BOD. Atrophic means something whose size is being diminished. This term is used in medical cases where organs or tissues shrink by their size.
So, the right answer is Option A.

Note: BOD is Biological oxygen demand is the amount of required oxygen for the degradation of organic waste and survival of contaminating microflora in water. Thus, it is a quality standard for checking the purity of water samples. Various BOD tests provide standards to scientists to study and control water pollution in streams, lakes, etc.