INVESTIGADORES
DIEGUEZ maria Del carmen
congresos y reuniones científicas
Título:
Total atmospheric mercury fluxes in Southern South America: seasonal dynamics recorded in the GMOS Station EMMA (Nahuel Huapi National Park, Patagonia, Argentina)
Autor/es:
DIÉGUEZ, MC; GARCÍA, PE
Lugar:
Roma
Reunión:
Workshop; GMOS (Global Mercury Observation System, Unión Europea FP7). Data quality assurance and quality control. Software QA/QC=data validation.; 2014
Institución organizadora:
CONSIGLIO NAZIONALE DELLE RICERCHE ITALIA
Resumen:
In North Patagonia several studies have reported high
levels of mercury (Hg) in deep
ultraoligotrophic lakes belonging to the Nahuel Huapi catchment, Nahuel Huapi
National Park (NHNP). NHNP limits at the west with an active volcanic region
with highly frequent eruptive events that impact east of the Andes due to the predominant
westerly winds. Volcanic activity and atmospheric transport across the Andes have
been proposed as the source of Hg to locations east of the cordillera. Mining,
industry and other potentially polluting activities are not developed within
the Park, thus levels of Hg recorded in the atmosphere may be considered as
natural. In contrast with the increasing evidence of mercury concentration and
fractionation within lakes, the identification and measurement of the potential
sources of mercury, atmospheric and precipitation Hg fluxes is at its starting
point. This investigation provides the first evidence of atmospheric Hg fluxes
in NHNP, obtained by continuous monitoring of gaseous elemental mercury (GEM)
at the EMMA station (Bariloche, 41° 7´43.82"S, 71°25´11.89"W, at 803
m a.s.l) belonging to the Global Mercury Observation System (GMOS).
Measurements of GEM consist of desorbed Hg detected by cold vapor atomic
fluorescence spectrometry at 253.7 nm using a Hg vapor analyzer Tekran 2537B,
within a 5 min time frame, from October 2012 to October 2013. Raw GEM data was
sorted out and validated in the frame of the quality control and quality
assurance procedures (QC/QA). GEM ranged between 0.22 and 1.33 ng m-3, with a
mean annual concentration of 0.90 ± 0.14 ng m-3 of GEM. The highest GEM
concentration (1.14 ng m-3) was recorded during the austral spring (October
2012) while lower concentrations (0.83 ng m-3) were measured during fall (April
2013). From spring towards fall, GEM concentrations showed a decreasing pattern
until April 2013. Afterwards a slight increase was recorded and, from May to
October GEM concentrations fluctuated between 0.9 and 1 ng m-3. The largest GEM
variability was found from January 2013 to April 2013, indicating a greater
dynamism likely due to pronounced day-night differences, characterized by lower
GEM concentrations at night (<1 ng m-3) and higher levels during daytime
(above 1.5 ng m-3). So far, GEM records at EMMA station resemble background
concentrations, comparable to levels found in Antarctica and remote South
Hemisphere locations.