Browsing by Subject "Soil"

Now showing 1 - 4 of 4
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    Assessing Unequal Airborne Exposure to Lead Associated With Race in the USA
    (Wiley, 2023-07-24) Laidlaw, Mark A. S.; Mielke, Howard W.; Filippelli, Gabriel M.; Earth and Environmental Sciences, School of Science
    Recent research applied the United States Environmental Protection Agency's Chemical Speciation Network and Interagency Monitoring of Protected Visual Environments monitoring stations and observed that mean concentrations of atmospheric lead (Pb) in highly segregated counties are a factor of 5 higher than in well‐integrated counties and argument is made that regulation of existing airborne Pb emissions will reduce children's Pb exposure. We argue that one of the main sources of children's current Pb exposure is from resuspension of legacy Pb in soil dust and that the racial disparity of Pb exposure is associated with Pb‐contaminated community soils.
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    Children's Blood Lead Seasonality in Flint, Michigan (USA), and Soil-Sourced Lead Hazard Risks
    (MDPI, 2016-03-25) Laidlaw, Mark A.S.; Filippelli, Gabriel M.; Sadler, Richard C.; Gonzales, Christopher R.; Ball, Andrew S.; Mielke, Howard W.; Department of Earth Sciences, School of Science
    In Flint; MI; USA; a public health crisis resulted from the switching of the water supply from Lake Huron to a more corrosive source from the Flint River in April 2014; which caused lead to leach from water lines. Between 2010 and 2015; Flint area children's average blood lead patterns display consistent peaks in the third quarter of the year. The third quarter blood lead peaks displayed a declining trend between 2010 and 2013; then rose abruptly between the third quarters of 2013 from 3.6% blood lead levels ≥5 µg/dL to a peak of about 7% in the third quarter of 2014; an increase of approximately 50%. The percentage of blood lead level ≥5 µg/dL in the first quarter of 2015 then dropped to 2.3%; which was the same percentage as the first quarter of 2014 (prior to the Flint River water source change). The Flint quarterly blood lead level peak then rose to about 6% blood lead levels ≥ 5 µg/dL in the third quarter of 2015; and then declined to about 2.5% in the fourth quarter of 2015. Soil lead data collected by Edible Flint food collaborative reveal generally higher soil lead values in the metropolitan center for Flint; with lower values in the outskirts of the city. The questions that are not being asked is why did children's blood lead levels display a seasonal blood lead pattern before the introduction of the new water supply in Flint; and what are the implications of these seasonal blood lead patterns? Based upon previous findings in Detroit and other North American cities we infer that resuspension to the air of lead in the form of dust from lead contaminated soils in Flint appears to be a persistent contribution to lead exposure of Flint children even before the change in the water supply from Lake Huron to the Flint River.
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    Effect of Soil Type and Fertilizer Application Timing on Phosphorus Leaching From Gypsum-Treated Agricultural Soils
    (2020-12) Cox, Kristiana; Jacinthe, Pierre-Andre; Wang, Lixin; Gilhooly, William P., III
    Phosphorus is an essential plant nutrient and an important contributor to the eutrophication of aquatic ecosystems. Studies have shown that gypsum (CaSO4∙H2O) applications can potentially reduce phosphorus export from agricultural fields. Most studies have examined the effect of gypsum application rates on treatment effectiveness, but limited research has been conducted to determine how the timing of gypsum application can affect soil phosphorus mobility and phosphorus leaching. A greenhouse experiment was conducted to address this question and further our understanding of the effect of gypsum addition on soil phosphorus chemistry. For the experiment, two soil types with different background phosphorus levels (low P, high P), and three different time intervals between gypsum and phosphorus fertilizer application (2, 28 and 56 days) were applied. A total of 18 soil columns (L: 15 cm; diam: 10 cm) packed with sieved soil were treated with gypsum (3.9 g) and separated into three sets corresponding to each of the phosphorus application times. An equal number of columns not treated with gypsum were also included to serve as controls. Phosphorus fertilizer (0.34 mg P cm-1) was added as KH2PO4 solution. Rainwater (58 mL) was applied every 2-4 days to generate leachate that was collected and analyzed for ortho-P, total P, and SO4-2. At the end of each time series, the set of soil columns were sliced into 2-4 cm increments, and water extractable and bicarbonate extractable phosphorus (Olsen-P) was determined to examine downward phosphorus movement. Results of the study showed that Olsen-P levels were not affected by the gypsum treatment, indicating no interference of gypsum treatment with the P-supplying capacity of soils. The gypsum treatment reduced water-extractable P levels in the high-P soil, but treatment effect was not significant in the low-P soil. Likewise, in the high-P soil, gypsum treatment resulted in leachate ortho-P reduction during the second and third period of collection. For the low-P soil, there was no significant reduction in ortho-P. Overall, these results indicated that the beneficial effect of gypsum on phosphorus export from agricultural fields is dependent on soil-P status and time interval between gypsum amendment and P fertilizer application.
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    New Approaches to Identifying and Reducing the Global Burden of Disease From Pollution
    (Wiley, 2020-03-25) Filippelli, Gabriel; Anenberg, Susan; Taylor, Mark; van Green, Alexander; Khreis, Haneen; Earth Sciences, School of Science
    Pollution from multiple sources causes significant disease and death worldwide. Some sources are legacy, such as heavy metals accumulated in soils, and some are current, such as particulate matter. Because the global burden of disease from pollution is so high, it is important to identify legacy and current sources and to develop and implement effective techniques to reduce human exposure. But many limitations exist in our understanding of the distribution and transport processes of pollutants themselves, as well as the complicated overprint of human behavior and susceptibility. New approaches are being developed to identify and eliminate pollution in multiple environments. Community-scale detection of geogenic arsenic and fluoride in Bangladesh is helping to map the distribution of these harmful elements in drinking water. Biosensors such as bees and their honey are being used to measure heavy metal contamination in cities such as Vancouver and Sydney. Drone-based remote sensors are being used to map metal hot spots in soils from former mining regions in Zambia and Mozambique. The explosion of low-cost air monitors has allowed researchers to build dense air quality sensing networks to capture ephemeral and local releases of harmful materials, building on other developments in personal exposure sensing. And citizen science is helping communities without adequate resources measure their own environments and in this way gain agency in controlling local pollution exposure sources and/or alerting authorities to environmental hazards. The future of GeoHealth will depend on building on these developments and others to protect a growing population from multiple pollution exposure risks.