Sousa, N.S.S.; Monteiro. M.C.; Gorayeb, A.; Costa, R.M., and Pereira, L.C.C., 2016. Effects of sewage on natural environments of the Amazon region (Pará-Brazil). In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 158–162. Coconut Creek (Florida), ISSN 0749-0208.

The negative effects of sewage discharge were analyzed in two Amazonian environments (the Caeté Estuary and the Cereja River) subject to different levels of anthropogenic impact. For this, samples of surface water were collected for the analysis of physical, chemical, and microbiological parameters during dry and wet season. In the Caeté Estuary, the results indicated high levels of total nitrogen and fecal coliforms in the upper sector. Eutrophic conditions were recorded in the wet and dry season. Natural and anthropogenic sources may contribute to the input of dissolved nutrients, maintaining the eutrophic conditions of the estuary. A similar pattern was observed in the Cereja River, with higher concentrations being found in the most urbanized sector, however, these water were mesotrophic. The planning and construction of a public sewage collection system and treatment plant by local authorities will be a key step towards the improvement of the water quality of the Caeté and Cereja rivers.