Just search for it on Google Scholar. There are heaps of papers about this. See e.g. http://scholar.google.se/scholar?hl=sv&q=macroinvertebrates+as+indicators&btnG=
This subject is one of my central research topic, you can have a look on what I have done in France: https://www.researchgate.net/profile/Cedric_Mondy/?ev=hdr_xprf.
Otherwise there are tons on papers you can find on scholar: http://scholar.google.fr/scholar?hl=fr&q=macroinvertebrates+indicators+water+quality&btnG=&lr=
You can find information on interpretation of your data analyses and indexes directly in the manuals, instructions an related papers published on http://www.aqem.de/, http://www.freshwaterecology.info ,