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1. Fate and transport of radioactive gypsum stack water entering the Floridan aquifer due to a sinkhole collapse

   https://doi.org/10.1038/s41598-018-29541-0  

   Sandhu, Daljit; Singh, Arvind; Duranceau, Steven J.; Nam, Boo Hyun; Mayo, Talea; Wang, Dingbao (July 2018, Scientific Reports)

   Abstract Groundwater aquifers are an essential source of drinking water, and must be protected against contamination. Phosphogypsum stacks originating from the processing of phosphate rock contain small amounts of radionuclides, such as²²⁶Ra. In September 2016, a sinkhole located beneath a phosphogypsum stack collapsed under central Florida’s carbonate karst terrain, where the aquifer is mostly confined, raising concern over water quality in the regions nearby. Monitoring and modeling the transport of the contaminated plume is vital to ensure drinking water criteria are met and to improve decision making regarding treatment. To achieve this, a geochemical modeling using PHREEQC software was employed to investigate the trajectory of the plume based on hydraulic and hydrologic conditions. Adsorption was simulated as a removal mechanism that could further reduce the intensity of the plume. The aquifer’s response to the release of contaminated water from the collapsed stack was quantified by simulating a number of scenarios, including variable radionuclide leakage quantities. Results suggest that it may take between 11–17 years and between 5.2 to 8.3 km from the sinkhole leak to reduce radionuclide concentrations to previous levels. Coupling the adsorption effect by minerals in Floridan aquifer (e.g. ferrihydrite, carbonate) can reduce radionuclide migration time to 9–16 years and distances between 4.3 to 7.8 km from the sinkhole leak. It can also reduce the distance needed to lower radionuclide concentrations, though not significantly. Additionally, due to the complexities of soil chemistry, the importance of groundwater remediation is emphasized. 

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2. A century of genetic variation inferred from a persistent soil‐stored seed bank

   https://doi.org/10.1111/eva.12675  

   Summers, Jennifer L.; Bernik, Brittany; Saunders, Colin J.; McLachlan, Jason S.; Blum, Michael J. (July 2018, Evolutionary Applications)

   Abstract Stratigraphic accretion of dormant propagules in soil can result in natural archives useful for studying ecological and evolutionary responses to environmental change. Few attempts have been made, however, to use soil‐stored seed banks as natural archives, in part because of concerns over nonrandom attrition and mixed stratification. Here, we examine the persistent seed bank ofSchoenoplectus americanus, a foundational brackish marsh sedge, to determine whether it can serve as a resource for reconstructing historical records of demographic and population genetic variation. After assembling profiles of the seed bank from radionuclide‐dated soil cores, we germinated seeds to “resurrect” cohorts spanning the 20th century. Using microsatellite markers, we assessed genetic diversity and differentiation among depth cohorts, drawing comparisons to extant plants at the study site and in nearby and more distant marshes. We found that seed density peaked at intermediate soil depths. We also detected genotypic differences among cohorts as well as between cohorts and extant plants. Genetic diversity did not decline with depth, indicating that the observed pattern of differentiation is not due to attrition. Patterns of differentiation within and among extant marshes also suggest that local populations persist as aggregates of small clones, likely reflecting repeated seedling recruitment and low immigration from admixed regional gene pools. These findings indicate that persistent and stratified soil‐stored seed banks merit further consideration as resources for reconstructing decadal‐ to century‐long records that can lend insight into the tempo and nature of ecological and evolutionary processes that shape populations over time. 

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3. Radiogenic Power and Geoneutrino Luminosity of the Earth and Other Terrestrial Bodies Through Time

   https://doi.org/10.1029/2019GC008865  

   McDonough, W_F; Šrámek, O.; Wipperfurth, S_A (July 2020, Geochemistry, Geophysics, Geosystems)

   Abstract We report the Earth's rate of radiogenic heat production and (anti)neutrino luminosity from geologically relevant short‐lived radionuclides (SLR) and long‐lived radionuclides (LLR) using decay constants from the geological community, updated nuclear physics parameters, and calculations of theβspectra. We track the time evolution of the radiogenic power and luminosity of the Earth over the last 4.57 billion years, assuming an absolute abundance for the refractory elements in the silicate Earth and key volatile/refractory element ratios (e.g., Fe/Al, K/U, and Rb/Sr) to set the abundance levels for the moderately volatile elements. The relevant decays for the present‐day heat production in the Earth (19.9 ± 3.0 TW) are from⁴⁰K,⁸⁷Rb,¹⁴⁷Sm,²³²Th,²³⁵U, and²³⁸U. Given element concentrations in kg‐element/kg‐rock and densityρin kg/m³, a simplified equation to calculate the present‐day heat production in a rock isurn:x-wiley:ggge:media:ggge22244:ggge22244-math-0001 The radiogenic heating rate of Earth‐like material at solar system formation was some 10³to 10⁴times greater than present‐day values, largely due to decay of²⁶Al in the silicate fraction, which was the dominant radiogenic heat source for the first∼10 Ma. Assuming instantaneous Earth formation, the upper bound on radiogenic energy supplied by the most powerful short‐lived radionuclide²⁶Al (t_1/2= 0.7 Ma) is 5.5×10³¹ J, which is comparable (within a factor of a few) to the planet's gravitational binding energy. 

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4. Quantifying soil accumulation of atmospheric mercury using fallout radionuclide chronometry

   https://doi.org/10.1038/s41467-024-49789-7  

   Landis, Joshua D; Obrist, Daniel; Zhou, Jun; Renshaw, Carl E; McDowell, William H; Nytch, Christopher J; Palucis, Marisa C; Del_Vecchio, Joanmarie; Montano_Lopez, Fernando; Taylor, Vivien F (December 2024, Nature Communications)

   Abstract Soils are a principal global reservoir of mercury (Hg), a neurotoxic pollutant that is accumulating through anthropogenic emissions to the atmosphere and subsequent deposition to terrestrial ecosystems. The fate of Hg in global soils remains uncertain, however, particularly to what degree Hg is re-emitted back to the atmosphere as gaseous elemental mercury (GEM). Here we use fallout radionuclide (FRN) chronometry to directly measure Hg accumulation rates in soils. By comparing these rates with measured atmospheric fluxes in a mass balance approach, we show that representative Arctic, boreal, temperate, and tropical soils are quantitatively efficient at retaining anthropogenic Hg. Potential for significant GEM re-emission appears limited to a minority of coniferous soils, calling into question global models that assume strong re-emission of legacy Hg from soils. FRN chronometry poses a powerful tool to reconstruct terrestrial Hg accumulation across larger spatial scales than previously possible, while offering insights into the susceptibility of Hg mobilization from different soil environments. 

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5. Exploration of advanced porous organic polymers as a platform for biomimetic catalysis and molecular recognition

   https://doi.org/10.1039/d0cc04351f  

   Zhang, Pengcheng; Wang, Sai; Ma, Shengqian; Xiao, Feng-Shou; Sun, Qi (September 2020, Chemical Communications)

   null (Ed.)

   Nature has long been a dominant source of inspiration in the area of chemistry, serving as prototypes for the design of materials with proficient performance. In this Feature article, we present our efforts to explore porous organic polymers (POPs) as a platform for the construction of biomimetic materials to enable new technologies to achieve efficient conversions and molecular recognition. For each aspect, we first present the chemical basis of nature, followed by depicting the principles and design strategies involved for functionalizing POPs along with a summary of critical requirements for materials, culminating in a demonstration of unique features of POPs. Our endeavours in using POPs to address the fundamental scientific problems related to biomimetic catalysis and adsorption are then illustrated to show their enormous potential and capabilities for applications ranging from concerted catalysis to radionuclide sequestration. To conclude, we present a personal perspective on the challenges and opportunities in this emerging field. 

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