Abstract

In Antarctic stations during the summer season the human population increases significantly in a short time, this can cause stress in the wastewater treatment system and changes in coast seawater quality due to increased production of wastewater. In this study in order to evaluate the effect of wastewater discharges in the vicinity of the Antarctic stations the spatial distribution of physical, chemical and microbiological parameters were determined. The measurement was done in seven permanent stations on King George Island, archipelago of the South Shetland Islands. Each of these Antarctic stations has different sewage treatment system. Five stations discharge their treated wastewater directly into the sea (Frei, Carlini, Great Wall, King Sejong and Escudero with Chilean Navy Station), one of the stations, Bellinhausen, discharges its treated wastewater to a small river flowing into sea and finally, the Artigas station stores its wastewater for transport out of the Antarctic continent. The samples were collected during January of the years 2014 and 2015 in Carlini, Great Wall, King Sejon and Artigas Stations. The samples next to Bellinhausen, Frei and Escudero Stations were collected between the year 2009 and 2015. All seawater samples were collected from sites evenly distributed around the sewage outfalls of the stations. Control samples were collected from pristine sites. Physical and chemical parameters (temperature, dissolved oxygen, pH, total phosphorus, total nitrogen and chemical oxygen demand) showed values not clearly related to the distance from the discharge point. Oils and fats only showed significant differences between the two sampling campaigns, due to a fuel spill occurred in December 2009 on Fildes Bay. The distribution of Fecal Coliforms in seawater exhibits a clear pattern associated with wastewater discharged. High densities of fecal coliforms (maximum 31000 CFU/100 ml) were found in seawater surrounding the sewage outfalls. However, the bacterial counts decreased rapidly with increasing distance from the outfall. In all samples collected further than 150 m from the outfall, the bacterial indicators were absent. Fecal coliforms were not detected at the pristine sites. Multivariate analysis revealed relationships between the variables that originally could not be observed, allowing the reduction of the dimensionality of the system. The human activities could change the water quality of the Antarctica environment in specific sites. This study has shown that contamination is limited to the immediate vicinity of the sewage outfall. Faecal coliforms turned out to be the best environmental quality control parameter of the effluent and its impact on the environment.