Estudio preliminar del Componente Biológico Planctónico de Pasivos Mineros en la Micro-Cuenca del río Pilaló, Pujilí – Cotopaxi.

Abstract

The study of planktonic component in the Pilalo River, Cotopaxi Province, Canton Pujilí, Tingo Parish, was carried out during the months of August and September 2012. The objectives were to establish the composition of planktonic communities and determine the organic pollution of the river. The study covered eight points between two locations: Recinto La Esperanza and Recinto Oriente. The methodology used to study the periphyton was in an area of 1cm2 using the technique of scraped in stone, and the filtering of 100 liters of water in a net of 60 um of pore. The samples were analyzed and recorded a total of 44,204 individuals grouped in 42 genera in 23 families in 13 orders. The more representative genera belong to Rhoicosphenia (14,668 individuals), Navicula (8,188 individuals) and Fragilaria (5,828 individuals). Applying the Margalef diversity indices and gamma, the report is a middle diversitiy index (2.85). According to the organic pollution index proposed by Palmer based on genera, the part of body of water studied shares three types of quality: low organic contamination, intermediate and high organic pollution. After the analysis the results determined that the body of water is located in the range of high organic pollution. According to Sorensen similitude index, by comparing the point 1 to the other 7 points, it presents similar percentages of less than 45%. Otherwise, by establishing comparison between the points from 2 to 8, there are similitude percentages from 64 to 87%. Based on the results, it is suggested to avoid the incidence of domestic and livestock activities, since they are the main source of generation of organic matter together with the rainwater fall because those factors have damaged the present conditions of the river. Moreover, it is suggested to extend the frequency of monitoring georeferenced points in the two seasons of the year to establish the characteristics of the population dynamics of the river.