4. Conclusions
In this work, a study of the occurrence and distribution profiles of 24 amines (aromatic amines and N-nitrosamines)
within a drinking water treatment plant was presented. Surface water was disinfected using chlorine that in the
presence of high doses of ammonia formed chloramines, which were really the final disinfectants. The analysis of the
data obtained, from a comprehensive sampling program involving several points of the utility (raw water, plant and
distribution system), led to the following conclusions: 1) 4 amines were detected in the water that supplied the DWTP,
although at very low levels; 2) the preoxidation/coagulation steps did not increase the levels of these 4 amines; 3) their
concentration increased after the chloramination step, however, appearing new amines, and 4) the subsequent
treatments (a second chlorination and a fluorination step) as well as the distance from the DWTP to the distribution system
did not have a relevant effect on the average concentrations of the 13 amines detected. From the study on the evaluation of the effect of seasonal variations in climate conditions (water temperature and rain) on the occurrence of the amines
throughout the DWTP, also it was observed that the levels of the 13 amines detected (after the chloramination step),
increased after rainfall events through runoff of amine precursors. This increasing on amine concentrations was also
noted in the coldest months mainly due to the lower oxidative effect of permanganate at low water temperatures. It is
noteworthy to mention that due to the high polluted/ impacted source water used for drinking water treatment
plant, the results obtained in this study should be considered to represent worst case occurrence of aromatic amines and Nnitrosamines, rather than typical values in drinking water. In accordance with this and taking into account the toxicity of
these amines, it would be desirable to include these compounds on the list of emerging contaminants in water.