Grantee Research Project Results
2022 Progress Report: An integrative approach for estimating childrens soil and dust ingestion rates
EPA Grant Number: R840209Title: An integrative approach for estimating childrens soil and dust ingestion rates
Investigators: Li, Li , Khlystov, Andrey , Li, Dingsheng , Fu, You , Son, Yeongkwon , Samburova, Vera , Liu, Yan
Institution: University of Nevada - Reno , Desert Research Institute
EPA Project Officer: Hahn, Intaek
Project Period: June 1, 2021 through May 13, 2025
Project Period Covered by this Report: June 1, 2022 through May 31,2023
Project Amount: $1,341,123
RFA: Estimating Childrens Soil and Dust Ingestion Rates for Exposure Science (2020) RFA Text | Recipients Lists
Research Category: Children's Health , Endocrine Disruptors , Human Health
Objective:
This project seeks to develop an innovative integrative approach, which fuses observational, analytical, computational, and statistical methods, to estimate dust/soil ingestion rates of children aged 6 months through 6 years with demographic and environmental variabilities.
Progress Summary:
As of May 2023, we have recruited 133 children of diverse ages, genders, races/ethnicities, parental education levels, housing conditions, and other demographic backgrounds. We have made joint observational, analytical, computational, and statistical efforts to obtain and leverage the individual-specific data associated with these children. Specifically,
- Using a systematic observational approach, we have conducted at least one round of structured observations focused on the touching and mouthing activities of all 133 children across various settings, including daycare centers, public parks, school playgrounds, and home backyards, during daylight hours. The gathered observational data underwent rigorous quality control and quality assurance measures. The level of agreement between two observers averaged at 88%, indicating a classification ranging from good to excellent in accordance with established kinesiological observation standards. The frequencies of both touching and mouthing behaviors aligned well with the ranges reported in existing literature. Furthermore, we have explored the associations between the frequencies of children's touching and mouthing behavior and their demographic information.
- We have finished at least one round of urine and stool sampling for 121 children. We have also collected 93 dust samples and 54 neighborhood soil samples; the numbers of dust and soil samples are fewer than the numbers of urine and stool samples because several children are from the same families or the same neighborhoods. We have completed analyzing the concentrations of 32 metals in most samples and are currently in the process of analyzing the concentrations of organic compounds in the samples. These concentration data are being used for a model-based estimation of the rate of dust/soil ingestion.
- We have published a human toxicokinetic model in support of quantitatively and mechanistically linking the human daily intake doses of organic chemicals with their concentrations in blood and urine. This model facilitates the inverse calculation of chemical and dust/soil ingestions for individual children. Moreover, we have compiled toxicokinetic parameters for metals, which underpin the development of a toxicokinetic modeling algorithm designed to calculate the optimal estimation of the rate of dust and soil ingestion by leveraging data from multiple children and multiple metals.
- We have published a regression-based method to “unzip” pooled measurements of chemical concentrations in biomonitoring studies. This statistical method allows the use of the data pooling strategy in this project, which may significantly reduce the cost and time associated with characterizing the specimens while retaining similar precision in statistical analysis.
Future Activities:
In Year 3, we plan to complete finalizing the recruitment of children from local daycare centers, elementary schools, and neighborhoods, and executing two rounds of behavior observations and collecting biospecimens and environmental samples for all the participating children. We will continue analyzing the concentrations of metals and organic compounds in environmental (dust and soil) and biological (urine and stool) samples. We will complete the development and assessment of human toxicokinetic models specifically tailored for metals and organic compounds, whereby we aim to perform preliminary reverse dosimetry modeling of dust and soil ingestion rates from measured biomarker concentrations in both environmental and biological samples. With the obtained observational and analytical data, we plan to use multivariate linear regression and structural equation modeling regression to infer children’s rates of dust/soil ingestion and investigate their association with demographic and environmental factors.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 8 publications | 5 publications in selected types | All 5 journal articles |
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Liu Y, Wang D, Li L, Li D. Assessing disparities in Americans’ exposure to PCBs and PBDEs based on NHANES pooled biomonitoring data. Journal of the American Statistical Association 2023 18:1-3. |
R840209 (2022) |
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Olsen AK, Li D, Li L. Explore the Dosimetric Relationship between the Intake of Chemical Contaminants and Their Occurrence in Blood and Urine. Environmental Science & Technology 2023. |
R840209 (2022) |
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Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.