water pollution - dissolved oxygen - the breath of life under water

Question 1

what does B.O.D. stand for?

Answer 1

biochemical oxygen demand

Question 2

Define biochemical oxygen demand

Answer 2

biochemical oxygen demand (B.O.D.) is defined as:
the amount of dissolved oxygen

consumed by biological (biochemical) action

when a sample of water is kept at 20degrees celcius

in the dark

for five days

Question 3

What does organic waste put a demand on when in water?

Answer 3

Organic waste, when in a water supply puts a demand on the dissolved oxygen content of the water

Question 4

What is dissolved oxygen necessary for?

Answer 4

This dissolved oxygen is necessary for aquatic life, fish and plants alike.

Question 5

What needs to be decomposed of if it is in the water?

Answer 5

If organic waste is in the water, it needs to be decomposed

Question 6

If oxygen waste is in the water, it needs to be decomposed. How is it decomposed?

Answer 6

bacteria and other organisms that are in the water carry out this decomposition.

Question 7

If there is too much waste in the water, what will there be a lot of as well and why?

Answer 7

If too much waste is in the water then a lot of bacteria will also be present as there is a lot of food for the bacteria

Question 8

What do the organisms in the water use up the oxygen to convert?

Answer 8

These organisms use up the dissolved oxygen to convert the waste into carbon dioxide and water and will reduce the oxygen content, so fish may die

Question 9

what happens when the oxygen content is reduced?

Answer 9

they fish may die

Question 10

Why does the water become polluted after waste enters it? (in terms of oxygen)

Answer 10

the way in which oxygen is absorbed into the water cannot keep up with the demand for the oxygen and so the water becomes polluted