What are the drawbacks of desalinating water?

Desalination creates heavily salted brine, which can harm sea life. Desalination also can leak the chemicals used into the "clean" water, resulting in health issues in the humans that drink it. The most effected sea life by the brine released by desalination would be plankton and photoplankton, which take damage from this.
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H=   2(area/a+b)h= 2(144/a+b)h= 2(144/18+18)h= 2(144/36)h= 2(4)h=8

Don’t use up to much of them it leads to pollution