Mercury measures up as global pollutant
The first evidence of changes in atmospheric Hg distribution was found by chemical analysis of lake sediments, ice cores and firn air records that are over 30 years old. However, it remains difficult to determine a global trend from the collected data sets. Against this backdrop, the EU-funded project GMOS (Global mercury observation system) established a worldwide monitoring network for Hg. This includes ground-based stations, shipboard measurements over the Pacific and Atlantic oceans and aircraft-based measurements in the troposphere and stratosphere. Furthermore, GMOS partners established data transfer protocols for all automated measurement systems. By combining data from ground-based stations with those from oceanographic and tropospheric measurement campaigns, they were able to map the temporal and spatial distribution of Hg in ambient air and marine ecosystems. The GMOS database conserves historical data to date and is continuously updated with data from the new monitoring network. In particular, Hg emissions data are used to evaluate spatial and temporal patterns of ambient concentrations related to energy production and manufacturing output. Moreover, as new data become available, model predictions can be checked against observations to fine-tune model parameters. GMOS focused on the critical importance of using new data to optimise models and accurately predict the changing Hg emissions and ecosystem response from local to global scales. Most Hg in the atmosphere occurs above the planetary boundary layer, namely the part of the atmosphere directly influenced by the Earth's surface. Data of the vertical redistribution of Hg has proved to be particularly useful for validating chemical transport models. Close cooperation with major international programmes ensures the immediate impact of both observational data and model output on the adoption of appropriate global legislation. GMOS has already provided significant support to the United Nations Environment Programme (UNEP) on a global legally binding instrument on Hg. Along with the UNEP Global Mercury Partnership, GMOS partners contributed solid scientific data to the negotiations of the Minamata Convention. This treaty aiming to protect humans and the environment from the adverse effects of Hg was signed in Geneva, Switzerland in 2013.
Keywords
Mercury, pollutant, GMOS, monitoring network, United Nations Environment Programme, Minamata
