One of the primary challenges to science writing is doing the research necessary to write what you need to write. This is a learned skill, and it is doing you no favors for us to just do your work for you. This is also, by the way, a forum policy. You say you looked for sources, but did not say where or how.
I'm pretty sure nobody here has oodles of literature on DDT or other organochlorine pesticides at their fingertips, unless they happen to be doing research in this exact area. Most of us would start where you should start: googling DDT and going from there. In the wikipedia article, which is pretty detailed, you quickly learn that DDT belongs to a class of pesticides called organochlorines. If you google "organochlorine pesticide", the first few hits include a review article or two that go into more detail on the toxic effects of organochlorine pesticides on living creatures than you could want (at the high school level, anyway).