Significance: Forest fires of the western United States have advanced upslope over the past few decades, scorching territories previously too wet to burn. We document an upslope advancement of high-elevation fires of 7.6 m/y, a rate comparable to the elevational velocity of vapor pressure deficit of 8.9 m/y. Strong interannual links between aridity and high-elevation forest fires and reduced influence of fire exclusion policies in montane mesic forests imply such changes are a byproduct of climate warming. We estimate that increased aridity between 1984 and 2017 exposed an additional 81,500 km ² of western US montane forests to fires. These changes have significant implications for terrestrial carbon storage, snowpack, and water quantity and quality.

Wildfires have short- and long-term impacts on the geoenvironment, including the changes to biogeochemical and mechanical properties of soils, landfill stability, surface- and groundwater, air pollution, and vegetation. Climate change has increased the extent and severity of wildfires across the world. Simultaneously, anthropogenic activities—through the expansion of urban areas into wildlands, abandonment of rural practices, and accidental or intentional fire-inception activities—are also responsible for a majority of fires. This paper provides an overall review and critical appraisal of existing knowledge about processes induced by wildfires and their impact on the geoenvironment. Burning of vegetation leads to loss of root reinforcement and changes in soil hydromechanical properties. Also, depending on the fire temperature, soil can be rendered hydrophobic or hydrophilic and compromise soil nutrition levels, hinder revegetation, and, in turn, increase post-fire erosion and the debris flow susceptibility of hillslopes. In addition to direct hazards, wildfires pollute air and soil with smoke and fire suppression agents releasing toxic, persistent, and relatively mobile contaminants into the geoenvironment. Nevertheless, the mitigation of wildfires’ geoenvironmental impacts does not fit within the scope of this paper. In the end, and in no exhaustive way, some of the areas requiring future research are highlighted.

The dramatic lack of diversity within science, technology, engineering, and mathematics (STEM) higher-education graduates is a serious issue facing the future of the STEM workforce. Colleges and universities are attempting to fix this disparity through targeted intervention programs aimed at increasing the persistence and retention of low-income, first-generation, and underrepresented (UR) students in STEM. A comprehensive synthesis of adopted strategies and analysis of their effectiveness is lacking. We conducted a systematic multiple-studies review, considering 31 empirical articles published between 2005 and 2020 that shared the outcomes of intentional intervention programs in place across the United States. We uncovered essential characteristics of successful programs and highlighted the top 10 critical program components to consider. These can be used to guide the development and execution of future programs’ support systems and interventions. This is a relatively new area of research, with most programs just in the earliest stages of implementation. It is essential to continue to follow the data on the outcomes of these programs, particularly their longitudinal impacts on the diversification of the STEM workforce, to be able to implement effective evidence-based practices.

Plastics are an essential commodity due to their superior engineering properties, durability and low cost for utilization in various commercial products. However, the degradation of plastics due to several environmental stresses has led to the formation of microplastics (MPs). MPs have risen to the top of environmental concerns due to their affinity to pollute the environment and to pass it to the food chain, threatening human health. In this context, attempts have been made to extract and characterise MPs from aqueous and solid matrices. A problem that not only hampers research but also regulatory decisions is the variety of methods used for the extraction and characterisation of MPs, especially in organic solid matrices (OSMs) with organic matter >5%, making the comparison of results difficult. This paper aims to address this by critically assessing the methodologies used for the extraction and qualitative and quantitative characterisation of MPs in OSMs. Further, the current impediments in the accurate characterisation of MPs in OSMs are identified, along with recommendations for future research. Finally, recent efforts by various countries to legislate against certain sources of MPs, as well as issues and novel techniques to remediate MPs from the soil, and wastewater have been highlighted.

Air sparging is a remediation technology for treating soil/groundwater contaminated with volatile organic compounds (VOCs). VOC removal during air sparging is rendered less effective because of the random formation of air channels, creating preferential paths for airflow, thus limiting remediation to these channels, referred to as a zone of influence (ZOI). Pulsation is a popular method used to improve the effectiveness of air sparging through cyclic operation, with the hope that air channels would form elsewhere. Pulsation makes air sparging more time-consuming. This paper studies the effects of one cycle of pulsation and air pressure on the airflow pattern and presents a laboratory study that investigated the effects of initial and further increases in the injected air’s pressure on the airflow pattern within a glass-bead medium used as a medium analogous to the soil. Digital images of airflow patterns were collected; these images show a larger radius of influence (ROI) and ZOI due to the initial air-pressure increase, particularly when a higher overburden pressure (i.e. the stress due to the partially saturated layer on top of the saturated soil-simulant layer) exists above the water-saturated zone. Further air-pressure increases seem to have no measurable effect on the ROI and the shape of the ZOI.