Effects of arsenic on the aquatic bacterial microbiota of the guayllabamba river in the heart of chontal-intag community

Abstract

The objective of this research was to evaluate the transformation suffered by the aquatic microbial communities of the Guayllabamba River due to Arsenic (As) as a product of mining production waste, as well as to identify bacterial species and analyze their ecological status through diversity indexes. Three sampling points were established in the Guayllabamba River. The first one can be found at the mine water contamination point (M1), the second one is 1.5 km downstream from the pollution site (M2) and the third one, 1.5 km upstream from the contamination point (M3). For the quantification of heavy metals, atomic absorption reading techniques are used. Molecular identification was also carried out through the DGGE analysis of the 16s rDNA. The results showed that the bacterial communities were reduced and specialized in the cause of the different types of animals in the previous points. Thus, concentrations of As (0.009 mg/l) were found in sample M1, concentrations of As (0.005 mg/l in sample M2 and finally, the sample M3 showed concentrations of As (0.004 mg/l). In the multidimensional scaling of the banding pattern, it was observed that M1 and M2 have a 60% of similarity to each other and 5% similarity to M3 The most representative genera in the DGGE analysis were: Firmicutes (29.41%), Proteobacteria (23.52%), Bacteroidetes (17, 64%), Actinobacteria (11.76%), Cyanobacteria (17.67%).