RESUMO
This study is aimed to identify the different sources of sedimentary organic matter (SOM) within Montevideo coastal zone (MCZ). To this end δ13C, δ15N and C/N ratio were analysed in surface sediments and a sediment core. Sediment core analysis showed that until ~1950CE SOM was mainly marine, observing a shift towards lower δ13C in recent sediments, evidencing an estuarine composition. This trend was associated to the climatic variability, which exerted a major influence on the SOM composition, leading to an increased input of terrigenous material and associated anthropogenic contaminants. Surface sediments collected during different El Niño South Oscillation (ENSO) phases did not show inter-annual variability in SOM composition, which was mainly marine in both eastern and western region of MCZ and estuarine in Montevideo Bay. This spatial pattern provides new insights on the dynamics and factors affecting organic matter sources available for primary consumers along the study region.
Assuntos
El Niño Oscilação Sul , Sedimentos Geológicos/química , Compostos Orgânicos/análise , Urbanização , Isótopos de Carbono/análise , Monitoramento Ambiental , Estuários , Isótopos de Nitrogênio/análise , UruguaiRESUMO
Human activities in the Antarctica including tourism and scientific research have been raised substantially in the last century with the concomitant impact on the Antarctic ecosystems through the release of wastewater mainly from different scientific stations activities. The aim of this study was to assess the wastewater contamination of surface waters and sediments of three melt-water streams (11 sites) by leaking septic tanks located in the vicinity of the Uruguayan Scientific Station in the Fildes Peninsula, King George Island, Antarctica, during summer 2015. For this purpose, we combined the analysis of fecal steroids in sediments by using gas chromatography and six enteric viruses in surface waters by quantitative and qualitative PCR. Coprostanol concentrations (from 0.03 to 3.31µgg-1) and fecal steroids diagnostic ratios indicated that stations C7 and C8 located in the kitchen stream presented sewage contamination. Rotavirus was the only enteric virus detected in five sites with concentration ranging from 1.2×105gcL-1 to 5.1×105gcL-1 being three of them located downstream from the leaking AINA and Kitchen septic tanks. This study shows for the first time the presence of both virological and molecular biomarkers of wastewater pollution in surface waters and sediments of three melt-water streams in the vicinity of a scientific station in the Antarctica. These results highlight the importance of the complementation of these biomarkers in two different matrices (surface waters and sediments) to assess wastewater pollution in an Antarctic environment related to anthropogenic activities in the area.
Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/análise , Rotavirus/isolamento & purificação , Esgotos/análise , Águas Residuárias/análise , Regiões Antárticas , Fezes/química , Fezes/virologia , Sedimentos Geológicos/virologia , Humanos , Esgotos/virologia , Águas Residuárias/virologiaRESUMO
Montevideo Bay is located in the middle zone of the Rio de la Plata, and since the foundation of the city, several key economic and environmental policies affected the industry, and thus, metal inputs into this ecosystem. The aim of this study is to evaluate the sedimentary geochemical record of Montevideo Bay, in order to determine the historical inputs of anthropogenic metals to the system. In addition, environmental and economic policies of the country were taken into account to infer the relationship between them and the historic metal input. Concentrations of aluminum, chromium, copper, lead, scandium and zinc were analyzed and the EF and SPI indices were calculated. The analysis showed that since Montevideo foundation, metal concentrations increased in accordance with industry development, and the indices as well as the metal concentration represent a reliable footprint of the history of different economic and environmental policies influencing historical industrial activities.
Assuntos
Baías/química , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Cidades , Desenvolvimento Econômico , Ecossistema , Política Ambiental , Sedimentos Geológicos/análise , UruguaiRESUMO
Benthic indices are commonly used tools for assessing the environmental quality, because they represent a simple source of scientific information. However, their performance could vary depending on the application area and perturbation types, thus they should be tested before used in other remote geographic regions. This study aims to test the use of some of the most widely common benthic biotic indices for assessing the environmental quality of Montevideo's coastal zone at a seasonal scale against many physicochemical variables. From all the evaluated indices, AMBI appears to be the most suitable one to assess the environmental quality. The study also allowed us to infer the most relevant physicochemical variables: protein, lipid and heavy metal sediment concentration. Additionally, site-specific threshold effect levels for heavy metals and biopolymers were established, which appear to be useful to determine tolerable levels of such stressors in future assessments or monitoring programs for the study area.