John Harley1, Ramón Gaxiola-Robles2, Tania Zenteno-Savín3, Lía Celina Méndez-Rodríguez4, Alfonso Enrique Bencomo-Alvarez5, Alisa Thiede6, Todd M O'Hara7. 1. Department of Chemistry and Biochemistry, University of Alaska Fairbanks, 900 Yukon Drive Rm 194, Fairbanks, AK, 99775-6160, USA. Electronic address: john.harley@alaska.edu. 2. Centro de Investigaciones Biológicas del Noroeste, S.C. Instituto Politécnico Nacional 195, Playa Palo Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096. Mexico; Hospital General de Zona No.1. Instituto Mexicano del Seguro Social. 5 de Febrero y Héroes de la Independencia, Centro, La Paz, Baja California Sur, C.P. 23000. Mexico. Electronic address: r.gaxiolar@gmail.com. 3. Centro de Investigaciones Biológicas del Noroeste, S.C. Instituto Politécnico Nacional 195, Playa Palo Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096. Mexico. Electronic address: tzenteno04@cibnor.mx. 4. Centro de Investigaciones Biológicas del Noroeste, S.C. Instituto Politécnico Nacional 195, Playa Palo Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096. Mexico. Electronic address: lmendez04@cibnor.mx. 5. Hospital General de Zona No.1. Instituto Mexicano del Seguro Social. 5 de Febrero y Héroes de la Independencia, Centro, La Paz, Baja California Sur, C.P. 23000. Mexico. Electronic address: aebencomo83@gmail.com. 6. Department of Biology and Wildlife, 211 Irving I, University of Alaska, Fairbanks, AK 99775, USA. Electronic address: arthiede@alaska.edu. 7. Department of Veterinary Medicine, University of Alaska Fairbanks, 901 Koyukuk Dr, Fairbanks, AK, 99775-7750, USA. Electronic address: tmohara@alaska.edu.
Abstract
INTRODUCTION: Previous studies of mercury (Hg) in pregnant women in the area of La Paz, Baja California Sur (BCS), Mexico found a proportion of individuals had concentrations of total Hg ([THg]) above some thresholds of concern set by health agencies. The [THg] were associated with fish and seafood consumption as well as other factors; although it was unclear which marine diet items could potentially be contributing to the concentrations observed. METHOD: We examined [THg] and monomethylmercury concentration ([MeHg+]) in the archived hair of 70 pregnant women from BCS as well as in diet items including fish, shellfish, and staple items (rice, beans, corn, and flour). We measured stable isotopes of carbon and nitrogen and employed a Bayesian stable isotope mixing model to investigate the proportion of fish and seafood in the isotopic profiles of archived hair samples. RESULTS: Concentrations of Hg species were low in staple foods and ranged from below detection limit to 5.71 parts per billion (ppb) wet weight. In hair, geometric mean [THg] was 658 ppb and [MeHg+] was 395 ppb, which were lower than previous reports. Percent MeHg+ was positively correlated with higher δ15N values. CONCLUSIONS: The largest carbon contributors to the diet of the study participants were corn and rice, and our analysis of fish contribution to diet varyingly agreed with the self-reported fish consumption. This report highlights the ability to discriminate potential sources of Hg from a diverse diet and the limitations of dietary recall studies.
INTRODUCTION: Previous studies of mercury (Hg) in pregnant women in the area of La Paz, Baja California Sur (BCS), Mexico found a proportion of individuals had concentrations of total Hg ([THg]) above some thresholds of concern set by health agencies. The [THg] were associated with fish and seafood consumption as well as other factors; although it was unclear which marine diet items could potentially be contributing to the concentrations observed. METHOD: We examined [THg] and monomethylmercury concentration ([MeHg+]) in the archived hair of 70 pregnant women from BCS as well as in diet items including fish, shellfish, and staple items (rice, beans, corn, and flour). We measured stable isotopes of carbon and nitrogen and employed a Bayesian stable isotope mixing model to investigate the proportion of fish and seafood in the isotopic profiles of archived hair samples. RESULTS: Concentrations of Hg species were low in staple foods and ranged from below detection limit to 5.71 parts per billion (ppb) wet weight. In hair, geometric mean [THg] was 658 ppb and [MeHg+] was 395 ppb, which were lower than previous reports. Percent MeHg+ was positively correlated with higher δ15N values. CONCLUSIONS: The largest carbon contributors to the diet of the study participants were corn and rice, and our analysis of fish contribution to diet varyingly agreed with the self-reported fish consumption. This report highlights the ability to discriminate potential sources of Hg from a diverse diet and the limitations of dietary recall studies.
Authors: Daniela A Murillo-Cisneros; Tania Zenteno-Savín; John Harley; Andrew Cyr; Pablo Hernández-Almaraz; Ramón Gaxiola-Robles; Felipe Galván-Magaña; Todd M O'Hara Journal: Chemosphere Date: 2020-12-07 Impact factor: 7.086