Browsing by Author "Sundararajan, Madhura"

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    Evaluation of Drinking Water Disinfectant Byproducts Compliance Data as an Indirect Measure for Short-Term Exposure in Humans
    (MDPI, 2017-05-20) Parvez, Shahid; Frost, Kali; Sundararajan, Madhura; Environmental Health Science, School of Public Health
    In the absence of shorter term disinfectant byproducts (DBPs) data on regulated Trihalomethanes (THMs) and Haloacetic acids (HAAs), epidemiologists and risk assessors have used long-term annual compliance (LRAA) or quarterly (QA) data to evaluate the association between DBP exposure and adverse birth outcomes, which resulted in inconclusive findings. Therefore, we evaluated the reliability of using long-term LRAA and QA data as an indirect measure for short-term exposure. Short-term residential tap water samples were collected in peak DBP months (May–August) in a community water system with five separate treatment stations and were sourced from surface or groundwater. Samples were analyzed for THMs and HAAs per the EPA (U.S. Environmental Protection Agency) standard methods (524.2 and 552.2). The measured levels of total THMs and HAAs were compared temporally and spatially with LRAA and QA data, which showed significant differences (p < 0.05). Most samples from surface water stations showed higher levels than LRAA or QA. Significant numbers of samples in surface water stations exceeded regulatory permissible limits: 27% had excessive THMs and 35% had excessive HAAs. Trichloromethane, trichloroacetic acid, and dichloroacetic acid were the major drivers of variability. This study suggests that LRAA and QA data are not good proxies of short-term exposure. Further investigation is needed to determine if other drinking water systems show consistent findings for improved regulation.
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    Pilot Tap Water Sampling Project to Study Urban Drinking Water Quality in Indianapolis for Community Exposure Assessment
    (Office of the Vice Chancellor for Research, 2014-04-11) Sundararajan, Madhura; Parvez, Shahid
    supply exposure data. This data is collected at treatment sites (water stations) and is not representative of true exposure concentrations to humans because of several known and unknown factors. These include temporal-spatial changes, source water type characteristics, retention time in the distribution systems, byproducts formation, poor condition of pipes, and water contamination. By the time water reaches its destination i.e., residential areas, its quality can deteriorate. Also, the water utilities do not test for un-regulated water contaminants which can be more potent. Due to the urban location of White River, Indianapolis drinking water supply has a higher risk of contamination with emerging contaminants such as pesticides, personal care-products, and pharmaceuticals. Hence, a direct method of water sampling is needed for true exposure assessment. Study Plan: We are designing a pilot tap water sampling project to study drinking water quality for pesticides and other urban contaminants in the Indianapolis Community Water System (IndyCWS). Seven residential sites are identified to capture sufficient parts of IndyCWS. The samples will be collected weekly, biweekly, and monthly during the April-June period. The samples will be analyzed in a certified laboratory using EPA recommended methods. The data from this study will be compared with utilities data, used to identify the presence of new contaminants, evaluate cumulative mixture exposure, and assess potential health risks. This work is currently in progress and the results from the study will be discussed in future meetings.
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    Residential Tap Water Monitoring of Disinfectant Byproducts to Assess Human Health Risk
    (Office of the Vice Chancellor for Research, 2015-04-17) Tedla, Sewit; Parvez, Shahid; Sundararajan, Madhura
    Disinfectant byproducts (DBPs) are commonly present in the community drinking water systems worldwide. Some of the DBPs are endocrine disruptors and believed to cause small for gestation age, preterm delivery, low birth weight and pubertal delay. The oral ingestion of drinking water is the primary exposure route for these chemicals in humans. Traditionally, epidemiologists rely on the indirect methods of exposure assessment (data supplied by water suppliers, exposure modeling, questionnaire etc.) to determine chronic health risk in humans. These methods are limited in scope because of inherent temporal-spatial variability, mixture interactions, and characteristics of water distribution networks. Therefore, we used a direct approach of collecting tap water samples from the residents to measure regulated DBPs (4-Trihalomethanes and 5-Haloacetic Acids) in Indianapolis Community Water System (Indy CWS). The ten residential sites are identified to capture the large part of Indy CWS. We collected samples on weekly, biweekly, and monthly basis during the May-July period. The samples were tested in a certified laboratory using EPA recommended methods. The measured concentrations of DBPs were above the permissible limits and show high temporal variability. The exposure data from this study will be used to estimate community exposure and their association with health outcomes. Currently, this work is in-progress and the results from the study will be discussed in the meeting.