Grantee Research Project Results
2022 Progress Report: Optimizing use of novel chemicals to assess childrens dust ingestion rates
EPA Grant Number: R840208Title: Optimizing use of novel chemicals to assess childrens dust ingestion rates
Investigators: Bennett, Deborah H. , Young, Thomas M , Kannan, Krunthachalam
Institution: University of California Davis , New York University
EPA Project Officer: Hahn, Intaek
Project Period: June 1, 2021 through May 31, 2024 (Extended to May 31, 2025)
Project Period Covered by this Report: June 1, 2022 through May 31,2023
Project Amount: $1,342,099
RFA: Estimating Childrens Soil and Dust Ingestion Rates for Exposure Science (2020) RFA Text | Recipients Lists
Research Category: Human Health , Children's Health
Objective:
The goals of this project are to: (1) Develop an innovative method for determining dust ingestion rates using compounds found primarily in indoor dust rather than outdoor soil, (2a) Measure dust ingestion in children living in homes from four distinct geographic areas with differing SES, urban/rural/suburban classification, and racial/ethnic composition and an additional cohort of children with autism or developmental delays, (2b) Determine the concentrations of a broad range of target and non-target compounds in house dust to improve understanding of indoor chemical exposures as a function of demographic variables, (3) Measure seasonal and age group variation in dust ingestion rates, and (4) Develop standard procedures for the dust tracer method to support its implementation by other organizations.
Progress Summary:
1. Selection of target compounds: An extensive amount of work was done to finalize the list of compounds we are targeting in the analysis of the dust, skin wipes, and food.
The ideal compound to be a marker in dust has the following properties:
- In nearly all dust samples
- Rarely has a secondary source of exposure for young children
- Has a measurable biomarker in urine
- For that biomarker, there is an understanding of what fraction is excreted as that biomarker
Most likely, the compound will be some sort of industrial compound used in items in and around the home, but not commonly used in personal care products, particularly cosmetics used by children. There may be a food ingredient or drug that is common enough to be in most homes, but would not be consumed by children. We anticipate that there is likely a suite of compounds that are possibilities, each of which has some limitations, but when taken as a whole, can be used to define the dust ingestion rate. In addition to measuring only for the potential tracers, our initial samples will need to also be measured for other compounds known to frequently be found in dust. This will allow us to have a confirmed identity for those compounds, and not spend time wondering what potential matches are and if any of those potential matches are good tracers.
We have the advantage of having 38 dust samples analyzed from a prior study, with many ubiquitous compounds confirmed. The dust has also been reevaluated with different annotation tools to pinpoint other potential markers, and identify some other compounds for confirmation of identity. We have also reviewed the literature to look at other compounds with existing biomarkers or for which biomarkers are under development.
Using these approaches, we generated our target compound list for potential dust markers as well as other compounds to measure in dust. Our targeted analysis panel will include 11 aromatic amines, 3 benzophenones, 4 bisphenols, 4 parabens, 3 polycyclic aromatic hydrocarbons, 13 organophosphate esters, 8 phenols, 14 phthalates, 15 fungicides, 4 herbicides, 3 neonicotinoids, 4 insecticides, 1 rodenticide, 26 other industrial compounds, approximately 30 compounds not listed above that were evaluated in a prior study of potential tracer compounds or that were found to be ubiquitous in dust, 3 drugs, 6 natural products, and 6 additional personal care ingredients.
2. Development of protocol: Protocols were developed in the first year of the study.
3. Participant recruitment: We have completed sample collection for a total of 13 participants, who had a child aged 2 years to 3.5 years old, for the methods development portion of the study. For these participants, a duplicate diet and skin wipe sample were collected in addition to dust and urine. Eleven of these participants have also collected a second sample 6 months later to assess temporal variability. We have collected dust and urine from 10 participants with autism spectrum disorder (ASD), and are in the process of scheduling an additional 7 participants. We have collected samples from 10 participants aged 6-24 months, with an additional 9 currently scheduling visits. We have collected samples from 13 participants age 4-5 years. We are in the process of scheduling 25 interested participants from southern California. We collected samples from an additional 11 participants locally age 2-3, all of whom intend to provide a second sample 6 months after their first sample. We have 5 participants age 2-3 scheduled locally who plan to provide a skin wipe sample in addition to the dust and urine samples.
4. Sample collection for Methods Development: As noted above, we had 13 participants complete the full method development sample collection. We procured a number of food samples representative of what children eat to supplement our knowledge of chemicals found in foods typical in the diet of children at this age. We are collected a limited methods development sample without food, including dust, urine, and skin wipe, for an additional 5 participants.
5. Collection of questionnaire data: We have collected data from participants in a high risk autism birth cohort and from an autism case control study from over 25 participants. We will use this to identify the range of answers to determine which participants and to determine if there are differences by developmental outcome. We are additionally utilizing an existing dataset that includes more limited questions on dust ingestion but was administered to several hundred participants in a case control study of ASD, developmental delay, and typically developing children.
Future Activities:
We are currently analyzing the food samples and will next analyze the dust and skin wipe data using our long list of targeted compounds listed above. We will determine which of these compounds looks most promising as a tracer to determine if those compounds or the metabolites can be measured in urine. We will additionally look at the non-target results to determine if there are any other additional compounds to consider. Then, we will impute dust ingestions rates for all the compounds for each child and then apply both the Best Tracer Method (BTM) and the Limiting Tracer Method (LTM) to evaluate candidate tracer chemicals for suitability. The combination of our targeted measurement of diverse compounds present in indoor environments with their associated metabolites will allow the first application of LTM and BTM for estimating dust ingestion rates. We will complete sample collection and then analyze the dust and urine for the entire group for the list of most likely tracers.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
indoor dust, dust Ingestion, hand-to-mouth activityProgress 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.