Terrestrial ecosystems, account for approximately 31% of the global land area and play a significant role in the biogeochemical cycling of toxic elements. Previous studies have explored the spatial patterns, effects, and drivers of toxic elements along urban gradients, agricultural lands, grasslands, and mining sites. However, the elevational patterns of toxic elements in montane ecosystems and the underlying drivers remain largely unknown. Atmospheric deposition is a crucial pathway through which toxic elements accumulate along terrestrial elevational gradients. The accumulation of toxic elements exhibited seasonal variability along elevational gradients, with higher deposition occurring in summer and winter. Approximately 46.77% of toxic elements (e.g. Hg) exhibited increasing trends with elevation, while 22.58% demonstrated decreasing patterns (Ba, Co). Furthermore, 8.06% displayed hump-shaped distributions (Ag), and 22.58% showed no distinct patterns (As and Zn). The accumulation of these elements is influenced by several key factors, including atmospheric deposition (26.56%), anthropogenic activities (14.11%), and precipitation (10.37%) primarily via wet deposition of atmospheric pollutants. The accumulation of toxic elements threatens terrestrial biodiversity by disrupting food chains, altering community structures, and causing individual mortality. These disruptions also pose risks to human health through contaminated food sources and food webs, potentially leading to health issues like cancer, organ damage, and reproductive challenges. This review offers key insights into the factors affecting the accumulation and distribution of toxic elements along elevation gradients. It also lays the groundwork for further study on how toxic elements impact ecosystem functions, which is crucial for protecting biodiversity under climate change.

Future anthropogenic land use change (LUC) may alter atmospheric carbonaceous aerosol (black carbon and organic aerosol) burden by perturbing biogenic and fire emissions. However, there has been little investigation of this effect. We examine the global evolution of future carbonaceous aerosol under the Shared Socioeconomic Pathways projected reforestation and deforestation scenarios using the CESM2 model from present-day to 2100. Compared to present-day, the change in future biogenic volatile organic compounds emission follows changes in forest coverage, while fire emissions decrease in both projections, driven by trends in deforestation fires. The associated carbonaceous aerosol burden change produces moderate aerosol direct radiative forcing (-0.021 to +0.034 W/m2) and modest mean reduction in PM2.5 exposure (-0.11 mu g/m3 to -0.23 mu g/m3) in both scenarios. We find that future anthropogenic LUC may be more important in determining atmospheric carbonaceous aerosol burden than direct anthropogenic emissions, highlighting the importance of further constraining the impact of LUC.

To safeguard historic centers with masonry buildings in medium-high seismic areas, the local seismic response (LSR) should be used. These portions of the urban areas are commonly characterized by complex subsurface features (i.e., underground cavities, buried anthropic structures, and archeological remains) that could be responsible for unexpected amplifications at period intervals similar to the building's ones. In this study, San Giustino's Square (Chieti, Italy) was considered due to the differentiated damage caused by the 2009 L'Aquila earthquake mainshock (6 April 2009 at 3:32 CEST, 6.3 Mw). Out of the eight buildings overlooking the square, the structure that suffered the heaviest damage was the Justice Palace. Two-dimensional finite element analyses have been carried out in San Giustino's square to predict the LSR induced by the seismic shear wave propagation. The influence of the Chieti hill, the anthropogenic shallow soil deposit, and the manmade cavity were investigated. The results outlined that the amplifications of the seismic shaking peaked between 0.2 and 0.4 s. The crest showed amplifications over a wide period range of 0.1-0.8 s with an amplification factor (FA) equal to 2. Throughout the square, FA = 2.0-2.4 was predicted due to the cavities and the filled soil thickness. The large amplified period range is considered responsible for the Justice Court damage.

Pollutant emissions in China have significantly decreased over the past decade and are expected to continue declining in the future. Aerosols, as important pollutants and short-lived climate forcing agents, have significant but currently unclear climate impacts in East Asia as their concentrations decrease until mid-century. Here, we employ a well-developed regional climate model RegCM4 combined with future pollutant emission inventories, which are more representative of China to investigate changes in the concentrations and climate effects of major anthropogenic aerosols in East Asia under six different emission reduction scenarios (1.5 degrees C goals, Neutral-goals, 2 degrees C -goals, NDC-goals, Current-goals, and Baseline). By the 2060s, aerosol surface concentrations under these scenarios are projected to decrease by 89%, 87%, 84%, 73%, 65%, and 21%, respectively, compared with those in 2010-2020. Aerosol climate effect changes are associated with its loadings but not in a linear manner. The average effective radiative forcing at the surface in East Asia induced by aerosol-radiation-cloud interactions will diminish by 24% +/- 13% by the 2030s and 35% +/- 13% by the 2060s. These alternations caused by aerosol reductions lead to increases in near-surface temperatures and precipitations. Specifically, aerosol-induced temperature and precipitation responses in East Asia are estimated to change by -78% to -20% and -69% to 77%, respectively, under goals with different emission scenarios in the 2060s compared to 2010-2020. Therefore, the significant climate effects resulting from substantial reductions in anthropogenic aerosols need to be fully considered in the pathway toward carbon neutrality.

Air quality in Bangladesh has depreciated over the years owing to substantial local and regional aerosol emissions. This study investigates the impact of anthropogenic aerosol emissions, aerosol radiative forcing, and socioeconomic factors on aerosol optical depth (AOD) over Bangladesh. The research focuses on the capital city Dhaka and the coastal island Bhola, using data from the ground-based AERONET, MODIS satellite, and MERRA-2 reanalysis model. AOD exhibited increasing trends over Bangladesh (0.004-0.010/years) and showed significant annual cycles. Northwestern regions of the country experienced extremely high concentrations of anthropogenic black carbon (BC) and organic carbon (OC) aerosols, whereas the central regions exhibited elevated anthropogenic SO2 and SO4 concentrations. The dominance of anthropogenic aerosols (SO4, BC, and OC) over Dhaka (similar to 75%) and natural aerosols (sea salt and dust) over Bhola (similar to 63%) were calculated. SO4 aerosol was the primary driving force over Dhaka contributing 47.60% of the total AOD, while sea salt aerosol was the dominant species (45.78%) over Bhola. High aerosol radiative forcing at the atmosphere (ARF(ATM)) values were calculated for both Dhaka and Bhola. Average heating rate (HR) at Dhaka was 2.05 +/- 0.75 K day(-1), and at Bhola was 1.54 +/- 0.58 K day(-1) indicating the presence of light-absorbing aerosols over Bangladesh. All the socioeconomic factors were positively correlated with AOD except population growth and agriculture land indicating the substantial impact of socioeconomic development on AOD. The findings of this study will have notable influences on long-term air quality management in Bangladesh as well as in Southeast Asia.

Rationale. Glaciers in the Tibetan Plateau (TP), especially in the Himalayas, are retreating rapidly due to rising air temperature and increasing anthropogenic emissions from nearby regions. Traditionally, pollutants deposited on the glaciers have been assumed to originate from long-range transport from its outside. Methodology. This study investigated the concentrations of black carbon (BC) and major ions in snowpit samples collected from two glaciers in the south-eastern TP (Demula and Palongzangbu) and one glacier in the west Himalayas (Jiemayangzong). The radiative forcing of BC was calculated based on BC concentration and glacier characteristics. Results. The results revealed that the BC/Ca2+ concentration ratio in snowpit samples from Palongzangbu, located near residential villages, is similar to 2.05 times higher than that of Demula, which is mainly influenced by long-range transported pollutants. Furthermore, on Jiemayangzong glacier, snowpit samples collected with 100-m vertical resolution exhibited that BC-induced radiative forcings at low altitude are similar to 2.37 +/- 0.16 times greater than those at high altitude. Discussion. These findings demonstrated that in addition to long-range transport, emissions from local residents also make substantial contributions to BC and certain major ions (e.g. SO42-). To accurately assess the sources and radiative forcing of BC and other light-absorbing impurities on glaciers of the TP, it is necessary to consider the impact of local populations and altitude-dependent variations.

Soil creep is a slow gravitational process. It differs from other catastrophic slope processes such as landslides, snow avalanches, and rockfalls in its dynamics and character. However, it can significantly affect tree growth. Creep movements can be analyzed based on the tree rings. This study analyzed the dynamics and spatiotemporal activity of creep in the Balea glacial valley (Southern Carpathians) under the Transfagarasan highway on an anthropogenic slope, using tree rings to define the spatiotemporal activity of creep and assess its potential driving and triggering factors. The dendrogeomorphological analysis included 54 Norway spruces (Picea abies (L.) Karst). A total of 118 tree-ring series were obtained, and a 35-year chronology was constructed based on the eccentric growth of tree rings and reaction wood, with a mean recurrence interval of 17.4 years. The spatial pattern of the disturbed trees in the event years was tested using Moran's I index. The presence of creep in this area is indicated by the stems of young trees taking on a 'd' shape or a 'pistol-butted' form, as well as the predominant inclination of the stems downslope direction. This inclination is not chaotic, as is typical of forests affected by landslides. The manifestation of creep is influenced by pre-existing factors, such as the substrate consisting of crystalline shale and the blanket of rubble arranged in the direction of the slope, as well as causal factors, such as the slope and precipitation. Precipitation falling within 24 h during June or July and intervals with frosty cycles from November to December and January to March were also contributing factors.

Mercury (Hg) is one of the most toxic global pollutants of continuing concern, posing a severe threat to human health and wildlife. Due to its mobility, Hg is easily transported through the atmosphere and directly deposited onto water, sediments and soils or incorporated in biota. In groundwater, Hg concentrations can be influenced by either geogenic or anthropogenic sources, causing critical health effects such as damage to the respiratory and nervous systems. The geogenic sources of Hg include rocks and minerals containing Hg (cinnabar, organic-rich shales, and sulfide-rich volcanic) and geothermal fluids. The anthropogenic Hg sources include the combustion of fossil fuels, gold mining, chemical discharges from dental preparation, laboratory activities and legacy sites. In groundwater, the average background concentration of Hg is < 0.01 mu g/L. Mercury can be mobilized into groundwater from geogenic or anthropogenic sources due to changes in redox potential (Eh), with concentrations reaching above the WHO drinking water standard of 1 mu g/L. Under reducing conditions, microbial activity facilitates the reductive dissolution of FeOOH, causing the release of sorbed Hg2+ into groundwater. The released Hg2+ may be reduced to Hg-0 by either dissolved organic matter or Fe2+. The stability of Hg species (Hg-0, Hg-2(2+), Hg2+, MeHg) in groundwater is controlled by Eh and pH. While high Eh and low pH conditions can mobilize Hg from the solid into aqueous phases, the soil binding ability can sequestrate the mobilized Hg via adsorption of Hg2+ by goethite, hematite, manganese oxides, hydrous ferric oxides, or organic matter restricting it from leaching into groundwater. During groundwater contamination, remediation using nanomaterials such as pumice-supported nanocomposite zero-valent iron, brass shavings, polyaniline-Fe3O4-silver diethyldithiocarbamate, and CoMoO/gamma-Al2O3 has been documented. These promising emerging technologies utilize the principle of adsorption to remove up to 99.98 % of Hg from highly contaminated groundwater. This study presents an overview of groundwater contamination, remediation, complex biogeochemical processes, and a hydrogeochemical conceptual model concerning Hg's mobility, fate, and transport.

Vehicle -emitted fine particulate matter (PM 2.5 ) has been associated with significant health outcomes and environmental risks. This study estimates the contribution of traffic -related exhaust emissions (TREE) to observed PM 2.5 using a novel factorization framework. Specifically, co -measured nitrogen oxides (NO x ) concentrations served as a marker of vehicle -tailpipe emissions and were integrated into the optimization of a Non -negative Matrix Factorization (NMF) analysis to guide the factor extraction. The novel TREE-NMF approach was applied to long-term (2012 - 2019) PM 2.5 observations from air quality monitoring (AQM) stations in two urban areas. The extracted TREE factor was evaluated against co -measured black carbon (BC) and PM 2.5 species to which the TREE-NMF optimization was blind. The contribution of the TREE factor to the observed PM 2.5 concentrations at an AQM station from the first location showed close agreement ( R 2 = 0 .79) with monitored BC data. In the second location, a comparison of the extracted TREE factor with measurements at a nearby Surface PARTiculate mAtter Network (SPARTAN) station revealed moderate correlations with PM 2.5 species commonly associated with fuel combustion, and a good linear regression fit with measured equivalent BC concentrations. The estimated concentrations of the TREE factor at the second location accounted for 7 - 11 % of the observed PM 2.5 in the AQM stations. Moreover, analysis of specific days known to be characterized by little traffic emissions suggested that approximately 60 - 78 % of the traffic -related PM 2.5 concentrations could be attributed to particulate traffic -exhaust emissions. The methodology applied in this study holds great potential in areas with limited monitoring of PM 2.5 speciation, in particular BC, and its results could be valuable for both future environmental health research, regional radiative forcing estimates, and promulgation of tailored regulations for traffic -related air pollution abatement.

Investigation of mercury (Hg) from atmospheric precipitation is important for evaluating its ecological impacts and developing mitigation strategies. Western China, which includes the Tibetan Plateau and the Xinjiang Uyghur Autonomous Region, is one of the most remote region in the world and is understudied in regards to Hg precipitation. Here we report seesaw-like patterns in spatial variations of precipitation Hg in Western China, based on Hg speciation measurements at nine stations over this remote region. The Hg fraction analyzed included total Hg (HgT), particulate-bound Hg (HgP) and methylmercury (MeHg). Spatially, HgT concentrations and percentage of HgP in precipitation were markedly greater in the westerlies domain than those in the monsoon domain, but the higher wet HgT flux, MeHg concentration and percentage of MeHg in precipitation mainly occurred in the monsoon domain. Similar spatial patterns of wet Hg deposition were also obtained from GEOSChem modeling. We show that the disparity of anthropogenic and natural drivers between the two domains are mainly responsible for this seesaw-like spatial patterns of precipitation Hg in Western China. Our study may provide a baseline for assessment of environmental Hg pollution in Western China, and subsequently assist in protecting this remote alpine ecosystem.