Exposure to uranium and co-occurring metals among pregnant Navajo women

Joseph H Hoover; Esther Erdei; David Begay; Melissa Gonzales; NBCS Study Team; Jeffery M Jarrett; Po-Yung Cheng; Johnnye Lewis

doi:10.1016/j.envres.2020.109943

Exposure to uranium and co-occurring metals among pregnant Navajo women

Environ Res. 2020 Nov:190:109943. doi: 10.1016/j.envres.2020.109943. Epub 2020 Jul 17.

Authors

Joseph H Hoover¹, Esther Erdei², David Begay², Melissa Gonzales³; NBCS Study Team²; Jeffery M Jarrett⁴, Po-Yung Cheng⁴, Johnnye Lewis²

Affiliations

¹ Montana State University BIllings, Billings, MT, United States. Electronic address: joseph.hoover@msubillings.edu.
² University of New Mexico Health Sciences Center, College of Pharmacy, Community Environmental Health Program, Albuquerque, NM, United States.
³ University of New Mexico Health Sciences Center, College of Pharmacy, Community Environmental Health Program, Albuquerque, NM, United States; University of New Mexico Health Sciences Center, School of Medicine, Albuquerque, NM, United States.
⁴ Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

Abstract

Navajo Nation residents are at risk for exposure to uranium and other co-occurring metals found in abandoned mine waste. The Navajo Birth Cohort Study (NBCS) was initiated in 2010 to address community concerns regarding the impact of chronic environmental exposure to metals on pregnancy and birth outcomes. The objectives of this paper were to 1) evaluate maternal urine concentrations of key metals at enrollment and delivery from a pregnancy cohort; and 2) compare the NBCS to the US general population by comparing representative summary statistical values. Pregnant Navajo women (N = 783, age range 14-45 years) were recruited from hospital facilities on the Navajo Nation during prenatal visits and urine samples were collected by trained staff in pre-screened containers. The U.S. Centers for Disease Control and Prevention (CDC), National Center for Environmental Health's (NCEH) Division of Laboratory Sciences (DLS) analyzed urine samples for metals. Creatinine-corrected urine concentrations of cadmium decreased between enrollment (1st or 2nd trimester) and delivery (3rd trimester) while urine uranium concentrations were not observed to change. Median and 95th percentile values of maternal NBCS urine concentrations of uranium, manganese, cadmium, and lead exceeded respective percentiles for National Health and Nutrition Evaluation Survey (NHANES) percentiles for women (ages 14-45 either pregnant or not pregnant.) Median NBCS maternal urine uranium concentrations were 2.67 (enrollment) and 2.8 (delivery) times greater than the NHANES median concentration, indicating that pregnant Navajo women are exposed to metal mixtures and have higher uranium exposure compared to NHANES data for women. This demonstrates support for community concerns about uranium exposure and suggests a need for additional analyses to evaluate the impact of maternal metal mixtures exposure on birth outcomes.

Keywords: Maternal biomonitoring; Metal mixtures; Metals; Navajo birth cohort study; Uranium; Urine.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Cohort Studies
Environmental Exposure* / analysis
Female
Humans
Middle Aged
Nutrition Surveys
Pregnancy
Uranium*
Young Adult

Substances

Uranium

Abstract

Publication types

MeSH terms

Substances

Grants and funding