|Abstract Title:||Monitoring Mercury from Austrian emission sources via tree rings from stem disks ? sampling of quadrants was important|
|Presenter Name:||Michael Tatzber|
|Company/Institution:||Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW) - Seckendorff-Gudent-Weg 8, A-1131 Vienna, Austria|
|Session:||Mercury Emissions: Monitoring and Analysis|
|Co-Authors:||Michael Tatzber,Alfred Frst|
Abstract Information :
Mercury is an environmental toxin, which is (in usual concentrations) not dangerous for the trees themselves, but there is interest to get as many data as possible about its distribution and cycling in environmental pools. On 16 August 2017, the Minamata Convention on Mercury entered into force. This agreement was introduced on an international level, because airborne mercury pollutions can reach very long distances. Forest ecosystems are known to enrich mercury from polluted airs and to store it for long time periods. With this respect, there is already information available for different pools of forest ecosystems (e.g. soils, foliage and twigs). For stemwood, the concentrations are comparably low which means an analytical challenge for their determinations. On the other hand, stemwood represents a very relevant pool in forest ecosystems regarding its biomass. As a consequence, mercury determinations in tree rings allow, firstly, following the historical impacts of industrial emissions which contained mercury and, secondly, to better estimate the mercury pool contained in this segment of the forest ecosystem. This would support model calculations of mercury flows in forest ecosystems. Analyses of several stem disks close to emission sources in Austria showed the importance to sample drill dust from different directions. As a consequence it was decided to divide every stem disk into four quadrants and to sample all of them separately. In this contribution, the results of the mercury determinations of three stem disks will be included. The first stem disk originates from the surrounding of a pig iron production site in Donawitz, which is located in Hinterberg (Styria, Austria). The second stem disc came from the immediate vicinity of a chlor-alkali electrolysis facility situated in Brckl (Carinthia, Austria). The third stem disk originated from a site close to a copper recycling facility in Brixlegg (Tyrol, Austria). For these entire stem disks, sampling of drilling dust from four quadrants improved the results markedly. The obtained trends in mercury concentrations obtained were readily explainable whenever information on changes in production processes was accessible. The maximum mercury concentration in the stem disc from Hinterberg was 20.8 ppb in the tree ring from 1970, the maximum mercury concentration of the stem disc from Brckl was 81.5 ppb in the tree ring from 1986 and the maximum mercury concentration of the stem disc from Brixlegg was 149.9 ppb in the tree ring from 1813. In sum, this approach allowed for surprisingly well explainable results and hence it can be recommended for further studies.