Browsing by Subject "chemical exposure"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    A Comparative Analysis of the Role Race and Socioeconomic Status Play in Chemical Exposure in the United States
    (2019-04-26) Early, Tara
    Environmental justice concerns arise when historically underrepresented groups are disproportionately exposed to toxins in the environment. Analysis of environmental biomonitoring data provides a method to analyze chemicals for race/ethnicity and income-related disparity. Using data from the US National Health and Nutrition Examination Survey 2013-2014, biomarker concentrations of 167 chemicals were analyzed. Ten subgroups were defined on the basis of race/ethnicity and income. To examine disparity, geometric mean (GM) concentrations of chemical biomarker for each subgroup were compared to a reference group (i.e., the non-Hispanic white individuals with poverty to income ratio ≥ 2). Of the 167 compounds considered, 95 were detected in >60% of samples and were evaluated for disparity. There was evidence of an environmental justice concern for 42 compounds (GM ratios significantly > 1) in at least one of the identified subgroups. For 21 of these compounds, disparity was present only in the low-income non-Hispanic Black subpopulation. Disparity was particularly pronounced for cotinine, propyl paraben, and dichlorophenol. GM ratios were significantly <1 for 16 chemicals, indicating higher exposure among high-income non-Hispanic whites. Cumulatively, this project demonstrates disproportionate exposure to environmental contaminants by income and race/ethnicity. Results suggest that the low-income non-Hispanic Black subpopulation experiences much higher instances of disparity. Comparing with prior research, results also suggest that disparity in environmental exposure may be increasing.
  • Thumbnail Image
    ItemEmbargo
    Connecting Environmental Exposures to Toxicology: Exposure studies using Silicon Wristbands and Whole Model Organisms
    (2024-04-26) Shahid, Sakina
    Silicone wristbands have emerged as passive sampling tools to monitor environmental contaminant exposures. They work by mimicking the skin, where SVOCs (semi volatile organic compounds) and VOCs (volatile organic compounds) can sorb onto the surface of the wristband and accumulate over time, providing time aggregated measures of chemical burden especially by dermal and inhalation routes of exposure. They are non-invasive compared to traditional techniques used to assess exposure, such as urine and serum collection, and relatively easy to transport and store, allowing for more participation. My research introduces an approach using zebrafish (Danio Rerio) to investigate biological responses to wristband extracts, focusing on neurobehavior as an endpoint. Neurobehavior is evaluated using a light/dark assay, wherein larvae respond to light and dark stimuli and deviation from the expected response to these stimuli is interpreted as indicative of potential developmental issues. After developing a protocol, I applied this methodology to explore the toxicity of chemicals captured on wristbands from a cohort based in a farming community at high risk of exposure to agrochemicals in Sri Lanka. The wristbands were worn for 7 days during a non farming season and captured varying exposures to chemical classes such as PAHs, Phthalates, Flame Retardants and Pesticides. Upon analyzing the total distance zebrafish swam in light and dark conditions, a Dunnet’s post hoc test revealed that zebrafish behavior in 7 out of 10 wristbands in the farmer group and 8 out of 10 wristbands in the non farmer group was statistically significantly different compared to the field blank. Most groups were showing hyperactivity in terms of the total distance traveled compared to the field blank, with one wristband exposure group showing hypoactivity. This was the first study to utilize wristband extracts for exposures in zebrafish, helping bridge the gap between exposure science and mixtures toxicology.