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Browsing by Author "Parvez, Shahid"
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Item 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 HealthIn 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.Item Exposure Characterization of Haloacetic Acids in Humans for Exposure and Risk Assessment Applications: An Exploratory Study(MDPI, 2019-01) Parvez, Shahid; Ashby, Jeffrey L.; Kimura, Susana Y.; Richardson, Susan D.; Environmental Health Science, School of Public HealthDisinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono-, di-, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels peaked in after-shower specimens, while TCAA levels remain unchanged. Correlation between urinary MCAA and TCAA was moderate but statistically significant. The prevalence of MCAA and TCAA in urine suggest they can be considered as biomarkers of HAA. Peak urinary MCAA in post-shower specimens suggest MCAA captures short-term exposure via dermal and/or inhalation, while urinary TCAA captures long-term exposure via ingestion. However, further research is warranted in a large pool of participants to test the reliability of MCAA as exposure biomarker.Item Glyphosate exposure in pregnancy and shortened gestational length: a prospective Indiana birth cohort study(Environmental Health, 2018-03) Parvez, Shahid; Gerona, R. R.; Proctor, C.; Friesen, M.; Ashby, J. L.; Reiter, J. L.; Lui, Z.; Winchester, P. D.Background Glyphosate (GLY) is the most heavily used herbicide worldwide but the extent of exposure in human pregnancy remains unknown. Its residues are found in the environment, major crops, and food items that humans, including pregnant women, consume daily. Since GLY exposure in pregnancy may also increase fetal exposure risk, we designed a birth-cohort study to determine exposure frequency, potential exposure pathways, and associations with fetal growth indicators and pregnancy length. Method Urine and residential drinking water samples were obtained from 71 women with singleton pregnancies living in Central Indiana while they received routine prenatal care. GLY measurements were performed using liquid chromatography-tandem mass spectrometry. Demographic and survey information relating to food and water consumption, stress, and residence were obtained by questionnaire. Maternal risk factors and neonatal outcomes were abstracted from medical records. Correlation analyses were used to assess relationships of urine GLY levels with fetal growth indicators and gestational length. Results The mean age of participants was 29 years, and the majority were Caucasian. Ninety three percent of the pregnant women had GLY levels above the limit of detection (0.1 ng/mL). Mean urinary GLY was 3.40 ng/mL (range 0.5–7.20 ng/mL). Higher GLY levels were found in women who lived in rural areas (p = 0.02), and in those who consumed > 24 oz. of caffeinated beverages per day (p = 0.004). None of the drinking water samples had detectable GLY levels. We observed no correlations with fetal growth indicators such as birth weight percentile and head circumference. However, higher GLY urine levels were significantly correlated with shortened gestational lengths (r = − 0.28, p = 0.02). Conclusions This is the first study of GLY exposure in US pregnant women using urine specimens as a direct measure of exposure. We found that > 90% of pregnant women had detectable GLY levels and that these levels correlated significantly with shortened pregnancy lengths. Although our study cohort was small and regional and had limited racial/ethnic diversity, it provides direct evidence of maternal GLY exposure and a significant correlation with shortened pregnancy. Further investigations in a more geographically and racially diverse cohort would be necessary before these findings could be generalized.Item Method to assess component contribution to toxicity of complex mixtures: Assessment of puberty acquisition in rats exposed to disinfection byproducts(Elsevier, 2017-08) Parvez, Shahid; Rice, Glenn E.; Teuschler, Linda K.; Simmons, Jane Ellen; Speth, Thomas F.; Richardson, Susan D.; Miltner, Richard J.; Hunter, E. Sidney, III; Pressman, Jonathan G.; Strader, Lillian F.; Klinefelter, Gary R.; Goldman, Jerome M.; Narotsky, Michael G.; School of Public and Environmental AffairsA method based on regression modeling was developed to discern the contribution of component chemicals to the toxicity of highly complex, environmentally realistic mixtures of disinfection byproducts (DBPs). Chemical disinfection of drinking water forms DBP mixtures. Because of concerns about possible reproductive and developmental toxicity, a whole mixture (WM) of DBPs produced by chlorination of a water concentrate was administered as drinking water to Sprague–Dawley (S–D) rats in a multigenerational study. Age of puberty acquisition, i.e., preputial separation (PPS) and vaginal opening (VO), was examined in male and female offspring, respectively. When compared to controls, a slight, but statistically significant delay in puberty acquisition was observed in females but not in males. WM-induced differences in the age at puberty acquisition were compared to those reported in S–D rats administered either a defined mixture (DM) of nine regulated DBPs or individual DBPs. Regression models were developed using individual animal data on age at PPS or VO from the DM study. Puberty acquisition data reported in the WM and individual DBP studies were then compared with the DM models. The delay in puberty acquisition observed in the WM-treated female rats could not be distinguished from delays predicted by the DM regression model, suggesting that the nine regulated DBPs in the DM might account for much of the delay observed in the WM. This method is applicable to mixtures of other types of chemicals and other endpoints.Item 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, Shahidsupply 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.Item 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, MadhuraDisinfectant 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.