ICMGP 2022 – On-Demand / Poster Presentation

Abstract Information :

The contribution of the Hg emission from soils and waterbodies is highly important to the global Hg cycle, as about 60% of the atmospheric Hg is a result of re-emission from waters and soils, of which major part involves recycling of previously deposited anthropogenic Hg. Moreover, logging activities have found to release Hg runoff but there are few data available on the role of atmospheric emissions during and after such activity. In our pilot experiment, flux measurements were conducted in a boreal forest in Eastern Finland to study the background air-soil and air-lake Hg fluxes and potential influence of clogging activities on the fluxes. Measurements were performed at five separate spots next to the clogging area, a reference spot, and lake measurement in June?August 2021. A dynamic flux chamber (DFC) coupled with an online Tekran analyser 2537X and a floating chamber system were used. Hg fluxes were mainly positive, i.e., the soil and the lake acted as sources of Hg. At the logging sites, the fluxes were -0.6?2.6 ng m-2 h-1 and at the reference site -0.2?0.8 ng m-2 h-1. Thus, with these few measurement days, the fluxes at the logging site were not much different from the reference site and similar to the fluxes measured at another background site in the boreal area of Finland (Kyll”nen et al., Wat Air Soil Poll. 223:3, 2012). Thus, our hypothesis of higher fluxes at the logging site was not supported with the measurement data, however, clogging had occurred 16 months before our campaign. Hg fluxes from water bodies were measured for the first time in Finland, and the emissions were on the same level as from the soil. A clear dependence with the temperature was found, however, with relative humidity the correlation was much weaker.