Question

What are the drawbacks of desalinating water?

Answer 1

¨One of the advantages of seawater desalination is that you can take an unlimited amount of water without affecting the freshwater ecosystem as we do now when we draw water from ground water, rivers and lakes.¨ The downside, however, is that seawater desalination is not very energy efficient.

Answer 2

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.
Hope this helped, and have a nice day!