Mercury (Hg) is a toxic metal that is easily released into the atmosphere as a gas or a particulate. Since Hg has serious health impacts based on human exposure, it is a major concern where it accumulates. Southern Florida is a region of high Hg deposition in the United States. It has entered the southern Florida environment for over 56 MY. For the past 3000 to 8000 years, Hg has accumulated in the Everglades peatlands, where approximately 42.3 metric tons of Hg was deposited. The pre-industrial source of mercury that was deposited into the Everglades was from the atmosphere, consisting of combined Saharan dust and marine evasion. Drainage and the development of the Everglades for agriculture, and other mixed land uses have caused a 65.7% reduction in the quantity of peat, therefore releasing approximately 28 metric tons of Hg into the southern Florida environment over a period of approximately 133 years. Both natural and man-made fires have facilitated the Hg release. The current range in mercury release into the southern Florida environment lies between 994.9 and 1249 kg/yr. The largest source of Hg currently entering the Florida environment is from combined atmospheric sources, including Saharan dust, aerosols, sea spray, and ocean flux/evasion at 257.1–514.2 kg/yr. The remobilization of Hg from the Everglades peatlands and fires is approximately 215 kg/yr. Other large contributors include waste to energy incinerators (204.1 kg/yr), medical waste and crematory incinerators (159.7+ kg/yr), and cement plant stack discharge (150.6 kg/yr). Minor emissions include fuel emissions from motorized vehicles, gas emissions from landfills, asphalt plants, and possible others. No data are available on controlled fires in the Everglades in sugar farming, which is lumped with the overall peatland loss of Hg to the environment. Hg has impacted wildlife in southern Florida with recorded excess concentrations in fish, birds, and apex predators. This bioaccumulation of Hg in animals led to the adoption of regulations (total maximum loads) to reduce the impacts on wildlife and warnings were given to consumers to avoid the consumption of fish that are considered to be contaminated. The deposition of atmospheric Hg in southern Florida has not been studied sufficiently to ascertain where it has had the greatest impacts. Hg has been found to accumulate on willow tree leaves in a natural environment in one recent study. No significant studies of the potential impacts on human health have been conducted in southern Florida, which should be started based on the high rates of Hg fallout in rainfall and known recycling for organic sediments containing high concentrations of Hg.

This teaching activity utilizes x-ray instrumentation combined with 3D printing to enhance students' understanding of unit cells. The activity involves measuring the unit cells of carbonate minerals like calcite, dolomite, and siderite using single crystal x-ray diffraction, and then 3D printing these unit cells for physical comparison and analysis. By substituting different cations, students can observe how unit cell dimensions change, illustrating key concepts in crystallography and mineralogy. The activity aims to make abstract crystallographic ideas tangible, promoting higher-order thinking skills such as analysis, evaluation, and spatial reasoning.

Aquifer storage and recovery (ASR) wells along northern Lake Okeechobee, Florida, have been proposed as part of the Comprehensive Everglades Restoration Plan. However, researchers have linked elevated concentrations of As, Hg and transition metals in groundwater because of ASR in carbonate rocks. This study presents portable X-ray fluorescence (pXRF) analyses of four continuous cores (C38S, C59, L63N, and L63S) recovered from the Floridan Aquifer System north of Lake Okeechobee, Florida. A total of 5078 pXRF measurements were collected at approximately 30.5 cm along the four cores. Measurements along the cores included the Intermediate Confining Unit, Upper Floridan Aquifer (UFA), Avon Park Permeable Zones (APPZ), and portions of the Lower Floridan Aquifer (LFA). Emphasis was placed on the concentrations of mercury (Hg), arsenic (As), molybdenum (Mo), chromium (Cr), and nickel (Ni), which have been identified as elements of concern during ASR operations. Major-element trends in the cores often reflect lithologic changes in the Floridan Aquifer System. This includes decreases in Ca and Sr and increases in Mg associated with dolomitization in the Avon Park Formation. Trace-metal concentrations vary systematically within hydrostratigraphic units. Mercury commonly exhibits elevated concentrations near the base of the UFA, whereas Mo is often enriched near the top of the UFA. Elevated concentrations of Hg, As, Mo, Ni, and other trace metals frequently occur at hydrostratigraphic boundaries, formation contacts, clay-rich intervals, and especially within organic-rich layers. Organic layers contained metal concentrations several times greater than surrounding carbonate rocks and hosted the highest measured concentrations of Hg, As, and Mo in the cores. The paucity of organic layers and generally lower metal concentrations in the UFA suggest it may represent a favorable zone for ASR storage. In contrast, the APPZ and LFA contain numerous metal-enriched organic layers which may increase the potential for trace metal mobilization during ASR operations. These results suggest pXRF characterization provides an effective tool for geochemical characterization of storage zones and evaluating water-quality risks potentially associated with ASR development.

Previous studies of rocks in California and Oregon suggest that a Late Jurassic ridge subduction event occurred. The geology of the Manastash inlier in Washington State supports this Late Jurassic ridge subduction. The biotite hornblende granodiorite and biotite hornblende tonalite of the Quartz Mountain stock and its cupolas are located in the Manastash inlier, central Cascades, Washington. This stock and its cupolas intrude the low-PT metamorphosed Lookout Mountain Formation turbidites—which are interpreted to have formed in a forearc depositional setting—and the suprasubduction zone Hereford Meadow amphibolite. A new single-crystal sensitive high-resolution ion microprobe–reverse geometry U-Pb age from stock zircons has an age of 157.4 ± 1.2 Ma (2σ). This new age corroborates the published age from the stock and is interpreted to be the crystallization age of the stock. New whole-rock major- and trace-element geochemistry suggests that the granitoids from this stock were generated by shallow mantle melting in a subduction zone setting. Geochemistry also suggests that the stock assimilated minor amounts of its wall rock and that the cupolas were generated from the same magmatic source as the main phase of the stock. The intrusion of the Quartz Mountain stock into the low-PT turbidites of the Lookout Mountain Formation and the suprasubduction zone Hereford Meadow amphibolite suggest that the magmas were generated by the subduction of a Late Jurassic spreading ridge. The geochemistry of the Quartz Mountain stock is similar to that of granitoids of the Taitao Peninsula, Chile, which were generated by the subduction of the Chile ridge during the late Neogene.