Browsing by Subject "Perchlorate"

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    Challenges in the Search for Perchlorate and Other Hydrated Minerals With 2.1-μm Absorptions on Mars
    (American Geophysical Union, 2018) Leask, E. K.; Ehlmann, B. L.; Dundar, M. M.; Murchie, S. L.; Seelos, F. P.; Computer and Information sciences, School of Science
    A previously unidentified artifact has been found in Compact Reconnaissance Imaging Spectrometer for Mars targeted I/F data. It exists in a small fraction (<0.05%) of pixels within 90% of images investigated and occurs in regions of high spectral/spatial variance. This artifact mimics real mineral absorptions in width and depth and occurs most often at 1.9 and 2.1 μm, thus interfering in the search for some mineral phases, including alunite, kieserite, serpentine, and perchlorate. A filtering step in the data processing pipeline, between radiance and I/F versions of the data, convolves narrow artifacts (“spikes”) with real atmospheric absorptions in these wavelength regions to create spurious absorption-like features. The majority of previous orbital detections of alunite, kieserite, and serpentine we investigated can be confirmed using radiance and raw data, but few to none of the perchlorate detections reported in published literature remain robust over the 1.0- to 2.65-μm wavelength range.
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    Urinary Iodine, Perchlorate, and Thiocyanate Concentrations in U.S. Lactating Women
    (Mary Ann Liebert, 2017-12) Lee, Sun Y.; McCarthy, Alicia M.; Stohl, Hindi; Ibrahim, Sherrine; Jeong, Christina; Braverman, Lewis E.; Ma, Wendy; He, Xuemei; Mestman, Jorge H.; Schuller, Kristin E.; Jahreis, Katherine A.; Pearce, Elizabeth N.; Leung, Angela M.; Obstetrics and Gynecology, School of Medicine
    Background: Iodine is an essential micronutrient for thyroid hormone production. Adequate iodine intake and normal thyroid function are important during early development, and breastfed infants rely on maternal iodine excreted in breast milk for their iodine nutrition. The proportion of women in the United States of childbearing age with urinary iodine concentration (UIC) <50 μg/L has been increasing, and a subset of lactating women may have inadequate iodine intake. UIC may also be influenced by environmental exposure to perchlorate and thiocyanate, competitive inhibitors of iodine transport into thyroid, and lactating mammary glands. Data regarding UIC in U.S. lactating women are limited. To adequately assess the iodine sufficiency of lactating women and potential associations with environmental perchlorate and thiocyanate exposure, we conducted a multicenter, cross-sectional study of urinary iodine, perchlorate, and thiocyanate concentrations in healthy U.S. lactating women. Methods: Lactating women ≥18 years of age were recruited from three U.S. geographic regions: California, Massachusetts, and Ohio/Illinois from November 2008 to June 2016. Demographic information and multivitamin supplements use were obtained. Iodine, perchlorate, and thiocyanate levels were measured from spot urine samples. Correlations between urinary iodine, perchlorate, and thiocyanate levels were determined using Spearman's rank correlation. Multivariable regression models were used to assess predictors of urinary iodine, perchlorate, and thiocyanate levels, and UIC <100 μg/L. Results: A total of 376 subjects (≥125 from each geographic region) were included in the final analyses [mean (SD) age 31.1 (5.6) years, 37% white, 31% black, and 11% Hispanic]. Seventy-seven percent used multivitamin supplements, 5% reported active cigarette smoking, and 45% were exclusively breastfeeding. Median urinary iodine, perchlorate, and thiocyanate concentrations were 143 μg/L, 3.1 μg/L, and 514 μg/L, respectively. One-third of women had UIC <100 μg/L. Spot urinary iodine, perchlorate, and thiocyanate levels all significantly positively correlated to each other. No significant predictors of UIC, UIC <100 μg/L, or urinary perchlorate levels were identified. Smoking, race/ethnicity, and marital status were significant predictors of urinary thiocyanate levels. Conclusion: Lactating women in three U.S. geographic regions are iodine sufficient with an overall median UIC of 143 μg/L. Given ubiquitous exposure to perchlorate and thiocyanate, adequate iodine nutrition should be emphasized, along with consideration to decrease these exposures in lactating women to protect developing infants.