From figure 2 we can understand that cultures of Bacteroidaceae and Bacteroides underwent a significant decrease in overall abundance when exposed to atrazine at concentrations over 20µg/L. Bacteroides predominate amongst the samples not treated with atrazine, indeed, a dese-dependent relationship can be observed: as specimens were exposed to higher concentrations of atrazine, a decrease in the abundance of Bacteroidaceae and Bacteroides was observed. Clostridium, Veillonella and Fusobacterium spp. were also quite common and displayed similar results. Bacteroides species normally form mutualisms, making up the most substantial portion of the mammalian gastrointestinal microbiota, where they play a fundamental role in processing of complex molecules to simpler ones in the host intestine (Wexler, H. M. (Oct 2007); Xu, J. .; Gordon, I. . (Sep 2003); Xu, J. et.al (2007).