In several sentences, please discuss:
a. What TMDLs are and how they are determined?
b. Why "dead zones" (e. g. in Gulf of Mexico) have little to no dissolved oxygen?
c. At least three reasons why ammonia-nitrogen is detrimental to a receiving body of water (e. g. stream) and its inhabitants.
d. What is the Streeter-Phelps dissolved oxygen (DO) sag curve?

Everything is explained below in the Explanation section.

Explanation:

a) TMDL stands for = Total Daily Maximum Loads

TMDL is the measure of total maximum amount of pollutant allowed in the water body. TMDL is a important tool to maintain the quality of water and measure the aquatic pollution.

Whereas, the formula to calculate TMDL is as follows:

TMDL =  Sum of waste load allocations (point source) + Sum of load allocations (non point sources and background) + Margin of Safety

b) Dead Zones :

Dead zones are zones which are termed as hypoxic which are low in oxygen because of the extreme aquatic pollution caused by human activities which in result deplete the oxygen level above the and below the oceans most required by the marine life. In addition, dead zones are those areas where oxygen is low and life in danger is high comparatively to other areas of oceans.

The main cause of that dead zones is because of eutrophication which means adding dangerous chemical nutrients in the water in exceeding amounts.

c) Why Ammonia-nitrogen is detrimental to waterbodies:

1. Ammonia nitrogen is a very toxic pollutant often found in landfills and sewage and waste products.

2. Ammonia nitrogen reduces the ability of water to disinfect its inhabitants and it reduces the purity. Furthermore, it changes the smell of the water and pollutes it.

3. Last but not the least, if you increase the concentration of ammonia nitrogen, the dissolved oxygen rate will be decreased and it has a inverse relation which is very dangerous to marine life underwater.

d) Streeter-Phelps DO curve:

Please refer to the attachment, I have attached the curve.

This curve is used to evaluate the dissolved oxygen in the water with varying distance.

It can be further studied from the curve that, how much loss sewage and other pollutants can endure upon the marine life.

it was a fall down when it happens

explanation: