Volume 16, No. 1, January 2016, Pages 46-60 PDF(964 KB)
Seasonal Variations of Total Gaseous Mercury at a French Coastal Mediterranean Site
Nicolas Marusczak1, Sabine Castelle1, Benoist de Vogüé1, Joël Knoery2, Daniel Cossa1
1 IFREMER, Centre de Méditerranée, CS 20330, F-83507, La Seyne-sur-Mer, France
2 IFREMER, Centre Nantes, BP 21109, F-44311, Nantes, France
- Investigation of 2 years of TGM at a French coastal Mediterranean site.
- Daily variations of TGM are observed, due to local industrial or urban activities.
- Seasonal variations are due to the dispersion of pollutants in the troposphere.
- High TGM concentrations are due to air masses coming from local or regional sources.
Total gaseous mercury (TGM) was continuously measured in 2009 and 2012, at a coastal site on the Mediterranean Sea (La Seyne-sur-Mer, France). Air temperature, humidity, wind speed and direction, and chemical parameters (O3, CO, NOx and PM10) were also measured as tracers of atmospheric pollution. Average TGM concentrations did not differ between the two years, 2.20 ± 0.54 and 2.16 ± 0.60 ng m–3 for 2009 and 2012 respectively. Diurnal variations of TGM were observed for both years and linked to local industrial or urban activities. Furthermore, a clear seasonal trend was observed, with TGM minima in summer and maxima in winter. This seasonality is common to several air pollutants, like the result of the variation in the dispersion of pollutants in the boundary layer and higher photochemical activity in summer. The highest TGM concentrations (> 3 ng m–3) were associated with air masses originating over urban and industrial areas of the Rhône Valley and local/regional anthropogenic sources. The influence of polluted air masses from these local/regional sources was confirmed by the significantly positive correlations between TGM and CO, NOx and PM10. We demonstrate that polluted air masses from nearby urban and industrial regions are an important source of TGM to Mediterranean coastal areas, rather than volatilization from the sea surface.
Total gaseous mercury; Coastal Mediterranean site; Anthropogenic and local sources; Seasonal and daily variations.