Impacts of wildfires and prescribed fires on mercury cycling and exposure: a global bibliometric analysis and scientific response-lag evaluation

Background: Mercury (Hg) pollution is a global environmental issue due to its severe neurotoxic effects on humans and ecosystems. As climate change increases, both the frequency and intensity of wildfires become significant contributors to global Hg cycling. Wildfires can release long-stored Hg from forest soils via evaporation, ash movement, and post-fire erosion. These processes can even stimulate methylmercury (MeHg) production in aquatic systems, amplifying ecological and human health risks. Prescribed burning, a forest management practice, results in lower-intensity combustion, which mainly re-emits surface-layer Hg and leaves deeper mineral soil pools relatively intact. However, this process may enhance short-term Hg mobility in soils and ash. We conducted a comprehensive bibliometric analysis to examine the evolution of wildfire- and prescribed burning–driven Hg cycling within scientific literature. Our objectives were to (1) quantify research growth and thematic evolution; (2) identify core research themes and knowledge clusters; (3) map global collaboration and institutional contributions; and (4) assess the geographic distribution of research in relation to fire-prone regions. Results: The analysis of 94 publications (1999–2025) reveals a considerable increase in research on fire-driven Hg cycling. The literature is centered on themes such as MeHg, atmospheric Hg, emissions, biomass burning, redeposition, and bioaccumulation. North America currently leads in research output; however, contributions from the Asia–Pacific region and South America are on the rise. Furthermore, we applied response-lag evaluation to examine the direction and delay of the effect of annual changes in wildfire activity on scientific output. At the global scale, annual fire frequency appeared to be positively associated with scientific publication output at a one-year lag, although this relationship should be interpreted as exploratory and non-causal. This finding reveals that the research community’s response to wildfire frequency both temporally and nationally. Also, interest in prescribed fire has risen in recent years. Conclusions: Overall, the results suggest that the field has become increasingly interdisciplinary, integrating perspectives from climate, ecology, and management. This growing body of research highlights the need for a deeper understanding of the impacts of fire on Hg cycling, which is crucial for supporting sustainable fire management and environmental policy.