Alshehri Talal, Jassim Amar Yasser, Cai Bo, Richardson Tammi L, Baalousha Mohammed
Center for Environmental Nanoscience and Risk, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
Environmental Health Department, College of Public Health, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia.
Nanomaterials (Basel). 2025 Mar 9;15(6):422. doi: 10.3390/nano15060422.
Fires at the wildland-urban interface (WUI) result in the release of ash into the atmosphere that can be transported for long distances and deposited on land and in oceans. Wildfire ash has the potential to increase phytoplankton biomass in the open ocean by providing both major nutrients and trace metals. However, fires that originate at the WUI contain potentially toxic concentrations of metals such as Ti, Cr, Cu, Pb, and Zn, especially in coastal oceans close to WUI fires, where ash deposition rates are high. Here, we investigated the impact of fire ash from different sources originating from vegetation, structures, and vehicles on growth of the diatom (). The diatom was exposed to ash suspensions containing equimolar concentrations of 10 and 50 µM Fe. The concentration of potentially toxic metals (e.g., Ti, Cu, and Zn) in the exposure suspensions decreased following the order vehicle ash suspension > structural ash suspension > vegetation ash suspension. Growth rates (GR) of were between 0.44 d and 0.52 d in the controls, and varied with ash types, following the order vegetation (GR = 0.40 d to 0.48 d) > vehicle (GR = 0.06 d to 0.46 d) > structure (GR = 0.02 d to 0.31 d) ash. Two ash samples (A 131 and A136) completely inhibited the growth of , possibly due to high Ti, Cu, and Zn concentrations in the form of (nano)particles. Overall, this study showed that structural and vehicle ash, with high concentrations of potentially toxic metals, significantly suppress the growth of , whereas vegetation ash with high concentrations of Fe and Mn but low concentrations of potentially toxic metals had no significant beneficial or suppressive effect. High concentrations of the metals Ti, Cu, and Zn in the form of nano(particles) in structural and vehicle ash are possible sources of toxicity to diatom growth. This study provides valuable insights into the potential impacts of WUI fires on aquatic ecosystems and can inform management strategies aimed at reducing these impacts.
城乡交错带（WUI）发生的火灾会将灰烬释放到大气中，这些灰烬可能会被远距离输送，并沉积在陆地和海洋中。野火灰有可能通过提供主要营养物质和微量金属来增加公海中浮游植物的生物量。然而，源自城乡交错带的火灾所含的金属（如钛、铬、铜、铅和锌）浓度可能具有毒性，尤其是在靠近城乡交错带火灾的沿海海域，那里的灰沉降率很高。在此，我们研究了来自植被、建筑物和车辆等不同来源的火灾灰烬对硅藻（）生长的影响。将硅藻暴露于含有等摩尔浓度10和50微摩尔铁的灰悬浮液中。暴露悬浮液中潜在有毒金属（如钛、铜和锌）的浓度顺序为车辆灰悬浮液>建筑灰悬浮液>植被灰悬浮液。在对照中，硅藻的生长速率（GR）在0.44 d至0.52 d之间，并随灰的类型而变化，顺序为植被（GR = 0.40 d至0.48 d）>车辆（GR = 0.06 d至0.46 d）>建筑（GR = 0.02 d至0.31 d）灰。两个灰样本（A 131和A136）完全抑制了硅藻的生长，这可能是由于（纳米）颗粒形式的高浓度钛、铜和锌所致。总体而言，本研究表明，含有高浓度潜在有毒金属的建筑和车辆灰显著抑制了硅藻的生长，而含有高浓度铁和锰但低浓度潜在有毒金属的植被灰没有显著的有益或抑制作用。建筑和车辆灰中纳米（颗粒）形式的高浓度金属钛、铜和锌可能是对硅藻生长产生毒性的来源。本研究为城乡交错带火灾对水生生态系统的潜在影响提供了有价值的见解，并可为旨在减少这些影响的管理策略提供参考。
