Diatoms as indicators of water quality in urban rivers

Diatoms can now be excellent indicators of water quality in urban rivers, especially if they serve as a source of water. The objective of this research was to determine the relationship between diatoms, water quality and urban rivers. The analysis of the data obtained indicated that in Europe, the use of diatoms as an indicator of water quality in urban rivers is already effective. As for Brazil, the data indicate in Rio Grande do Sul and Paraná; the researches of this triad are in an evolutionary phase. Northeast region, Pernambuco, the use is not yet as effective as in the south, In Amazonas and Pará, the researches for the composition of the triad in the Water Quality Index (IQA), still does not present effectiveness, one of the explanations is the lack of insertion in the existing legislations as the variables to be analyzed, among them, the use of diatoms. Therefore, the IQA without the complementation of the diatomaceous analysis may be incomplete due to the indication of other chemical variables such as, for example, polycyclic aromatic hydrocarbons not included in the current IQA.