The study of toxic heavy metals in the environment is challenging because metals are a natural component of our environment. As such, they have disfinct biogeochemical cycles that govern their mobility, fate, and toxicity. A failure to understand these biogeochemical cycles will lead to a failure to adequately assess adverse impacts. Current risk assessment techniques for metals via the oral ingesfion route are based on operationally defined tests which mimic the release of metals from soil in the human digestive system. A goal of this proposal is to be able to define the bioaccessibility of metals in geochemical terms, not based on operafionally defined extraction methods. These goals will be tested through a combination of laboratory and in situ studies of metal-contaminated soils and mining wastes to characterize the interplay of processes that increase metal bioavailability over time and those that decrease metal bioavailability over time. Through these experiments, we will test whether the bioaccessibility of metals through oral ingestion can be predicted from the underiying speciation of metals and the characterisfics ofthe soil itself. This study will bridge the current gap between geology and toxicology. Current risk assessment methods can determine if metals in a soil may exert risk, but not why. It is our intent to show that through the incorporafion of a modest amount of geochemical analysis, we can greatly improve risk assessment for metals in soils by showing why some soils exert risk while other soils with similar levels of metals do not exert risk. In addifion, with a similarly modest understanding of the temporal cycling of metals, we can show that bioaccessibility of metals in soils is not fime invariant. With this knowledge, risk assessment can be proactive in understanding the nature of both current and future risks.

Public Health Relevance

The goals of this project directly align with the larger goals of the Superfund Basic Research Program. Our study is highly relevant to their Exposure Assessment Goals (we will develop tools to improve site assessment techniques through a better understanding of bioavailability), which in turn fits in with the goal of improving Risk Assessments at contaminated locafions.

National Institute of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Hazardous Substances Basic Research Grants Program (NIEHS) (P42)
Project #
Application #
Study Section
Special Emphasis Panel (ZES1-LWJ-M (O1))
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Harvard University
United States
Zip Code
Rosa-Parra, Jose A; Tamayo-Ortiz, Marcela; Lamadrid-Figueroa, Hector et al. (2018) Diurnal Cortisol Concentrations and Growth Indexes of 12- to 48-Month-Old Children From Mexico City. J Clin Endocrinol Metab 103:3386-3393
Lee, Jane J; Valeri, Linda; Kapur, Kush et al. (2018) Growth parameters at birth mediate the relationship between prenatal manganese exposure and cognitive test scores among a cohort of 2- to 3-year-old Bangladeshi children. Int J Epidemiol 47:1169-1179
Sun, Ryan; Carroll, Raymond J; Christiani, David C et al. (2018) Testing for gene-environment interaction under exposure misspecification. Biometrics 74:653-662
Sun, Ryan; Wang, Zhaoxi; Claus Henn, Birgit et al. (2018) Identification of novel loci associated with infant cognitive ability. Mol Psychiatry :
Woo, May K; Young, Elisabeth S; Mostofa, Md Golam et al. (2018) Lead in Air in Bangladesh: Exposure in a Rural Community with Elevated Blood Lead Concentrations among Young Children. Int J Environ Res Public Health 15:
Wang, Zhaoxi; Claus Henn, Birgit; Wang, Chaolong et al. (2017) Genome-wide gene by lead exposure interaction analysis identifies UNC5D as a candidate gene for neurodevelopment. Environ Health 16:81
Wagner, Peter J; Park, Hae-Ryung; Wang, Zhaoxi et al. (2017) In Vitro Effects of Lead on Gene Expression in Neural Stem Cells and Associations between Up-regulated Genes and Cognitive Scores in Children. Environ Health Perspect 125:721-729
von Stackelberg, Katherine; Li, Miling; Sunderland, Elsie (2017) Results of a national survey of high-frequency fish consumers in the United States. Environ Res 158:126-136
Valeri, Linda; Mazumdar, Maitreyi M; Bobb, Jennifer F et al. (2017) The Joint Effect of Prenatal Exposure to Metal Mixtures on Neurodevelopmental Outcomes at 20-40 Months of Age: Evidence from Rural Bangladesh. Environ Health Perspect 125:067015
Claus Henn, Birgit; Bellinger, David C; Hopkins, Marianne R et al. (2017) Maternal and Cord Blood Manganese Concentrations and Early Childhood Neurodevelopment among Residents near a Mining-Impacted Superfund Site. Environ Health Perspect 125:067020

Showing the most recent 10 out of 96 publications