versión On-line ISSN 0717-6538
TOLEDO, Héctor et al. STUDY OF MONTHLY AND SEASONAL FAECAL CONTAMINATION IN THE COASTAL AREA ADYACENT TO THE SUBMARINE WASTEWATER DIFFUSER IN THE BAY OF PUERTO MONTT. Gayana (Concepc.) [online]. 2005, vol.69, n.1, pp. 104-112. ISSN 0717-6538. http://dx.doi.org/10.4067/S0717-65382005000100011.
The coastal area of the interior sea of the Tenth Region, including the Reloncaví Sound, is an area that since the first inhabitants settled down in their surroundings it has been impacted by domestic and industrial wastewater, as well as for agricultural, forestry and fish farming activities in the last 10 years. The coastal area of the bay of Puerto Montt has been little studied, mainly when someone tries to evaluate the current state of the environmental conditions and further more, when pretending to know the possible impacts generated after the installation of a submarine wastewater diffuser. The present study seeks to obtain a diagnosis of the state of bacteriological contamination of the bay of Puerto Montt, by using the faecal coliform index. Five sampling stations in the coast and six in deeper waters of the bay were established, the last six parallel to the first ones. Sampling in the coastal stations was performed monthly and seasonally in deep waters stations of the bay. For the bacteriological analysis of the water samples, the multiple tubes method was used (MPN), a quantitative method that allows to estimate the population of faecal coliforms bacteria present in the water, by inoculating series of 5 tubes in decreasing dilutions of the sample into proper cultivation media. For the analysis of the information, parametric variance analysis, Tukey test and test t of Student were performed. The bacteriological contamination shows ranges of seasonal faecal coliforms between <2 and 1700 and monthly between 2 and >16000 NMP fc/100 ml. Finally, it can be point out that the population of faecal coliforms in the bay of Puerto Montt has remained stable in relation to previous reports. However, it is considered essential to continue with the monitoring of the submarine wastewater diffuser, as well as the detailed study of the oceanography of the Reloncaví Sound, of which they have been obtained some records by means of satellite oceanography
Palabras clave : Faecal coliforms; submarine wastewater diffuser; contamination.