Grantee Research Project Results
2023 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, 2023 through May 31,2024
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:
The project was originally envisioned to run from June 1, 2021, to May 31, 2024. In March 2024, the U.S. Environmental Protection Agency agreed to extend it by one full year, until May 31, 2025. As of May 2024, we have completed two rounds of behavior observations and environmental and biospecimen sampling, one in a cold/wet season and the other in a hot/dry season, for 110 children across diverse age groups, genders, races/ethnicities. In addition, we have completed one round of behavior observations and environmental and biospecimen sampling for another 33 children. 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 structured observations of touching and mouthing activities among the participating children (two rounds for 110 and one round for 33) in daycare centers, public parks, school playgrounds, and home backyards, during the daylight hours. 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 measured concentrations of 32 metals in urine and stool samples (two rounds for 110 and one round for 33), household dust (two rounds for 60 and one round for 21), and neighborhood soil samples (two rounds for 25 and one round for 19). 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 are currently in the process of analyzing the concentrations of organic compounds in the samples.
We have developed an algorithm to reliably estimate dust/soil ingestion rates by leveraging simultaneous measurements of multiple metal tracers in urine, stool, household dust, and neighborhood soil samples while harmonizing uncertainties in these measurements. This method is based on the premise that when dust/soil ingestion is the primary or sole pathway for a child’s intake of these metals, the calculated ingestion rate should be consistent across different metal tracers, regardless of which specific tracers are used. The algorithm optimizes each child’s daily urine flow rate and fecal excretion rate to achieve the best agreement between the dust/soil ingestion rates calculated from a maximized set of metal tracers. We are currently in the process of applying this algorithm to estimate dust/soil ingestion rates for all participating children.
We have coded multivariate regression models for statistical analysis of the impacts of demographic, environmental, and behavioral factors on children’s dust/soil ingestion rates.
This project involves human subjects and has been subject to oversight by the Institutional Review Board (IRB) at the University of Nevada, Reno. The IRB thoroughly examined our submitted Continuing Review/Progress Report for Year 3 and granted approval for the annual renewal on July 10, 2024.
Future Activities:
In Year 4, we plan to complete the analysis of organic compound concentrations in all environmental and biospecimen samples. We will apply the developed algorithm to estimate dust/soil ingestion rates for all participating children. In addition, we will finalize the development and evaluation of human toxicokinetic models specifically tailored for organic compounds, with the goal of conducting preliminary reverse dosimetry modeling of dust and soil ingestion rates based on measured biomarker concentrations. Using the collected observational and analytical data, we intend to employ multivariate linear regression and structural equation modeling to estimate children’s dust/soil ingestion rates and examine their associations with demographic, environmental, and behavioral factors. Finally, we will prepare manuscripts and a final report for submission.
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 |
|---|
| Type | Citation | ||
|---|---|---|---|
|
|
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;118(543):1538-50. |
R840209 (2023) |
Exit |
|
|
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;57(26):9526-37. |
R840209 (2023) |
Exit |
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.