The measured BOD values for four different water samples (A-D) are as follows: A = 3 ppm; B = 18 ppm; C = 21 ppm; D = 4 ppm;. The water samples which can be called as highly polluted with organic wastes, are
The question asks us to determine which water samples are highly polluted with organic wastes based on their Biochemical Oxygen Demand (BOD) values. BOD is a measure of the amount of oxygen that microorganisms will consume while decomposing organic matter in water. It is an indicator of the level of pollution in water. Typically, the higher the BOD value, the more polluted the water is with organic matter.
Given the BOD values for the water samples:
Sample A: 3 ppm
Sample B: 18 ppm
Sample C: 21 ppm
Sample D: 4 ppm
Generally, a BOD value:
< 5 ppm indicates clean water with low organic pollution.
Between 5-20 ppm indicates moderately polluted water.
Greater than 20 ppm indicates heavily polluted water.
Now, let's analyze the given samples:
Sample A has a BOD of 3 ppm, indicating that it is clean and not heavily polluted.
Sample B has a BOD of 18 ppm, indicating moderately polluted water.
Sample C has a BOD of 21 ppm, which indicates a high level of pollution with organic waste.
Sample D has a BOD of 4 ppm, also indicating clean water with low organic pollution.
Among the options provided:
B and C: Sample B's BOD value indicates moderate pollution, and Sample C's BOD value indicates high pollution.
This combination makes sense because Sample C is highly polluted, and Sample B is at the boundary of moderate to high pollution.
Thus, the samples that can be classified as highly polluted with organic wastes, according to their BOD values, are B and C.
