Grantee Research Project Results
2022 Progress Report: Developmental, behavioral & environmental determinants of infant dust ingestion
EPA Grant Number: R840202Title: Developmental, behavioral & environmental determinants of infant dust ingestion
Investigators: Adolph, Karen E , Boor, Brandon Emil , Claxton, Laura J , Laskin, Alexander
Institution: New York University , Purdue University
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 2021 through August 31, 2024
Project Period Covered by this Report: September 1, 2021 through August 31,2022
Project Amount: $1,336,404
RFA: Estimating Childrens Soil and Dust Ingestion Rates for Exposure Science (2020) RFA Text | Recipients Lists
Research Category: Children's Health , Human Health
Objective:
This project will elucidate determinants of indoor dust ingestion in 6- to 24-month-old infants (age range for major postural and locomotor milestones). Our 5 specific objectives are to test: (1) whether the frequency and characteristics of indoor mouthing events change with age and motor development stage for different micro-environments; (2) how home characteristics and demographic factors affect indoor dust mass loading and dust toxicant concentration; (3) how dust transfer between surfaces is influenced by dust properties, surface features, and contact dynamics; and (4) contributions of developmental, behavioral, and socio-environmental factors to dust and toxicant-resolved dust ingestion rates. In addition, the project will (5) create a shared corpus of video, dust, toxicant, and ingestion rate data to increase scientific transparency and speed progress through data reuse by the broader exposure science community.
Progress Summary:
From September 2021 to August 2022, we made progress toward our 5 objectives as follows:
(Objective 1): To test change in mouthing events across age and motor development, we constructed and validated a set of behavioral codes from 54 infants (13- and 23-month-olds) in an existing data set using the same protocol for the one-hour video of natural activity in the EPA grant. We completed preliminary analyses of mouthing in 54 hours of natural home video data.
To collect new behavioral data, we developed a protocol to video record one hour of natural activity in the home with caregivers and infants (6 to 24 months). We built a parent-facing public website (baby-exploration-project.com) to recruit families into the study and to provide them with information. By August 2022, we completed 7 of the planned 216 home visits across the two sites. We developed and validated workflows and quality assurance plans for the behavioral data.
(Objective 2) To test effects of homes and demographics on dust mass loadings and toxicant concentrations, we developed a protocol for home video tours accompanied by laser measurements of room dimensions. We video record the cleaning products and floor cleaning equipment in each room. We developed a parent-report questionnaire to obtain information about the home environment, indoor and outdoor sources of dust, the frequency and type of surface cleaning/vacuuming, ventilation and filtration methods, and shoe track-in potential.
We developed a protocol to collect floor dust samples from 2-3 sites in each home using handheld vacuums, nylon dust collection socks, anti-static aluminum nozzles, and steel stencils. We evaluated the dust mass collection efficiency using ultrafine and coarse test dust and real floor dust. We developed a protocol for gravimetric analysis of the dust collection socks and storage materials. We prepared dust collection packages for use by the baby labs and created a labeling scheme and tracking spreadsheet for each dust collection sock and package. We developed a protocol for sieving and separating the floor dust samples and created a database of un-sieved and sieved floor dust mass loadings. We developed a procedure to determine floor dust mass, volume, and number of size distributions using a laser diffraction particle sizer. We developed a procedure to determine the bulk dust index of refraction and apparent density. We developed and validated quality assurance plans for the dust gravimetric and laser diffraction analysis.
We conducted pilot experiments with collected dust samples to investigate components of toxicological concern such as environmental persistent free radicals, heavy toxic metals, and persistent organic pollutants.
(Objective 3) To simulate dust transfer from floor-to-hand and hand-to-mouth, we built an environmental chamber and devised a system to collect quantitative data on infant hand size. We created a clean air supply system to provide dust-free air to the chamber at variable volumetric airflow rates and relative humidities. We designed the chamber to house a robotic contact simulator, floor surface samples with simulated dust deposits, and instrumentation to measure resuspended dust size distributions in the air. We designed a robotic contact simulator to simulate infant hand-to-floor contacts based on infant crawling data. We created an experimental matrix for experiments in the environmental chamber to systematically evaluate how behavioral and environmental factors affect dust migration and redistribution in infants’ microenvironments.
(Objective 4) We have not begun to analyze contributions of developmental, behavioral, and socio-environmental factors to dust ingestion.
(Objective 5) To create a shared corpus of behavioral and dust data, we created and began populating a curated volume on Databrary to be openly shared with authorized investigators.
Future Activities:
In Year 2, we will continue data collection, conducting QA and coding behavioral data from the videos as they are collected. We will analyze dust mass loadings, size distributions, morphological features, and toxicant concentrations as data are collected. We will begin building and testing the robotic contact simulator and conducting the controlled dust migration experiments in the environmental chamber. We will determine size-resolved dust contact transfer and resuspension fractions associated with infant hand-to-floor contact and begin estimating age-specific dust ingestion and inhalation rates using a mass balance model and preliminary behavioral data. We will document composition and concentrations (mass of toxicant per mass of indoor dust) of EPFR, HTM, POP in the dust samples. Findings will allow predictive understanding of the effects of the indoor environment on potential ingestion of hazardous toxicants.
Journal Articles:
No journal articles submitted with this report: View all 6 publications for this projectRelevant Websites:
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.