I would like some help regarding the utilization of "of them" in a sentence. The sentence is from an a text summarizing a research work.
The original sentence I have written in the text was: "Efficiency of chlorination process for simultaneous degradation of two pesticides, A and B, at high and low pesticide concentrations was investigated in pond water." I utilized the word "pesticides" second time, since I was concerned that the readers would not be able to understand what concentrations I am speaking of: chlorine or pesticide concentrations.
The text was edited as: "Efficiency of chlorination process for simultaneous degradation of two pesticides, A and B, at high and low concentrations of them was investigated in pond water." the editor probably didn't want to utilize the word pesticides 2 times.
But I really find the way of utilizing "of them" strange and sounding quite annoying.
PS. Shall I put "the" in front of "chlorination process". I think it's quite general so it is not required. But when I speak specifically of the chlorination process that I have applied in my study (at specific conditions), then I shall utilize "the"?
Thanks for the assistance! Then I will leave "of them" in the sentence and won't contradict with my professor :) But still, somehow, doesn't quite sound good when I read it. Maybe that's because I'm not a native English speaker.