The potential wildfire effects on mercury remobilization from topsoils and biomass in a smelter-polluted semi-arid area

0520936 - GLÚ 2021 RIV GB eng J - Journal Article
Tuhý, M. - Rohovec, Jan - Matoušková, Šárka - Mihaljevič, M. - Kříbek, B. - Vaněk, A. - Mapani, B. - Göttlicher, J. - Steininger, R. - Majzlan, J. - Ettler, V.
The potential wildfire effects on mercury remobilization from topsoils and biomass in a smelter-polluted semi-arid area.
Chemosphere. Roč. 247, May (2020), č. článku 125972. ISSN 0045-6535. E-ISSN 1879-1298
R&D Projects: GA ČR(CZ) GA19-08614S
Institutional support: RVO:67985831
Keywords : Mercury * Topsoils * Vegetation * Wildfire
OECD category: Environmental sciences (social aspects to be 5.7)
Impact factor: 7.086, year: 2020
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0045653520301648

Wildfires can be responsible for significant mercury (Hg) emissions especially in contaminated areas.Here, we investigated the Hg distribution in topsoils and vegetation samples and temperature-dependent Hg mobilization from biomass-rich topsoils collected near a copper (Cu) smelter in Tsumeb(semi-arid Namibia), where Hg-rich Cu concentrates are processed. The thermo-desorption (TD) ex-periments conducted on representative biomass-rich topsoils (3.9e7.7 mg Hg/kg) indicated that morethan 91% of the Hg was released at ~340 C, which corresponds to the predominant grassland-fireconditions. The mineralogical investigation indicated that the Hg comes mainly from the depositedsmelter emissions because no distinct Hg-rich microparticles corresponding to the windblown dust fromthe nearby disposal sites of the technological materials (concentrates, slags, tailings) were found. Acomparison with the TD curves of the Hg reference compounds confirmed that the Hg in the biomass-rich topsoils occurs as a mixture of Hg bound to the organic matter and metacinnabar (black HgS), whichexhibits similarities with the TD pattern of smelterflue dust residue. Despite the installation of a sulfuricacid plant in the smelter in 2015 and a calculated drop in the estimated Hg emissions (from1301±457 kg/y for the period 2004e2015 to 67±5 kg/y after 2015), the Hg legacy pool in the smelter surroundings can potentially be re-emitted back to the atmosphere by wildfire. Using the Hg spatialdistribution data in the area (184 km²), the estimates indicate that up to 303 kg and 1.3 kg can beremobilized from the topsoils and vegetation, respectively.
Permanent Link: http://hdl.handle.net/11104/0305627