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Rasheduzzaman M, O'Connell B, Krometis LA, Brown T, Cohen A. Point-of-use chlorine residuals and disinfection byproduct occurrences in rural households served by public water utilities in Appalachian Virginia. JOURNAL OF WATER AND HEALTH 2024; 22:1064-1074. [PMID: 38935457 DOI: 10.2166/wh.2024.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 05/10/2024] [Indexed: 06/29/2024]
Abstract
We characterized concentrations of trihalomethanes (THMs), a measure of disinfection byproducts (DBPs), in tap water samples collected from households with utility-supplied water in two rural counties in Appalachian Virginia, and assessed associations with pH, free chlorine, and metal ions which can impact THM formation. Free chlorine concentrations in all samples (n = 27 homes) complied with EPA drinking water guidelines, though 7% (n = 2) of first draw samples and 11% (n = 3) of 5-min flushed-tap water samples exceeded the US Safe Drinking Water Act (SDWA) maximum contaminant level (MCL) for THM (80 ppb). Regression analyses showed that free chlorine and pH were positively associated with the formation of THM levels above SDWA MCLs (OR = 1.04, p = 0.97 and OR = 1.74, p = 0.79, respectively), while temperature was negatively associated (OR = 0.78, p = 0.38). Of the eight utilities serving study households, samples from water served by three different utilities exceeded the EPA MCL for THM. Overall, these findings do not indicate substantial exposures to DBPs for rural households with utility-supplied water in this region of southwest Virginia. However, given the observed variability in THM concentrations between and across utilities, and established adverse health impacts associated with chronic and acute DBP exposure, more research on DBPs in rural Central Appalachia is warranted.
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Affiliation(s)
- Md Rasheduzzaman
- Department of Population Health Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Bethesda O'Connell
- Department of Community and Behavioral Health, East Tennessee State University (ETSU), Johnson City, TN 37614, USA
| | - Leigh-Anne Krometis
- Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Teresa Brown
- Department of Natural Sciences, University of Virginia's College at Wise, Wise, VA 24293, USA
| | - Alasdair Cohen
- Department of Population Health Sciences, Virginia Tech, Blacksburg, VA 24061, USA; Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA E-mail:
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Skalaban TG, Thompson DA, Madrigal JM, Blount BC, Espinosa MM, Kolpin DW, Deziel NC, Jones RR, Beane Freeman L, Hofmann JN, Ward MH. Nitrate exposure from drinking water and dietary sources among Iowa farmers using private wells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170922. [PMID: 38350573 DOI: 10.1016/j.scitotenv.2024.170922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/09/2024] [Accepted: 02/10/2024] [Indexed: 02/15/2024]
Abstract
Nitrate levels are increasing in water resources across the United States and nitrate ingestion from drinking water has been associated with adverse health risks in epidemiologic studies at levels below the maximum contaminant level (MCL). In contrast, dietary nitrate ingestion has generally been associated with beneficial health effects. Few studies have characterized the contribution of both drinking water and dietary sources to nitrate exposure. The Agricultural Health Study is a prospective cohort of farmers and their spouses in Iowa and North Carolina. In 2018-2019, we assessed nitrate exposure for 47 farmers who used private wells for their drinking water and lived in 8 eastern Iowa counties where groundwater is vulnerable to nitrate contamination. Drinking water and dietary intakes were estimated using the National Cancer Institute Automated Self-Administered 24-Hour Dietary Assessment tool. We measured nitrate in tap water and estimated dietary nitrate from a database of food concentrations. Urinary nitrate was measured in first morning void samples in 2018-19 and in archived samples from 2010 to 2017 (minimum time between samples: 2 years; median: 7 years). We used linear regression to evaluate urinary nitrate concentrations in relation to total nitrate, and drinking water and dietary intakes separately. Overall, dietary nitrate contributed the most to total intake (median: 97 %; interquartile range [IQR]: 57-99 %). Among 15 participants (32 %) whose drinking water nitrate concentrations were at/above the U.S. Environmental Protection Agency MCL (10 mg/L NO3-N), median intake from water was 44 % (IQR: 26-72 %). Total nitrate intake was the strongest predictor of urinary nitrate concentrations (R2 = 0.53). Drinking water explained a similar proportion of the variation in nitrate excretion (R2 = 0.52) as diet (R2 = 0.47). Our findings demonstrate the importance of both dietary and drinking water intakes as determinants of nitrate excretion.
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Affiliation(s)
- Timothy G Skalaban
- Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, MD, United States of America; Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, United States of America
| | - Darrin A Thompson
- Center for Health Effects of Environmental Contamination, The University of Iowa, Iowa City, IA, United States of America
| | - Jessica M Madrigal
- Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, MD, United States of America
| | - Benjamin C Blount
- Tobacco and Volatiles Branch, National Center for Environmental Health, U.S. Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Maria Morel Espinosa
- Tobacco and Volatiles Branch, National Center for Environmental Health, U.S. Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Dana W Kolpin
- U.S. Geological Survey, Central Midwest Water Science Center, Iowa City, IA, United States of America
| | - Nicole C Deziel
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, United States of America
| | - Rena R Jones
- Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, MD, United States of America
| | - Laura Beane Freeman
- Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, MD, United States of America
| | - Jonathan N Hofmann
- Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, MD, United States of America
| | - Mary H Ward
- Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, MD, United States of America.
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Chen D, Parks CG, Beane Freeman LE, Hofmann JN, Sinha R, Madrigal JM, Ward MH, Sandler DP. Ingested nitrate and nitrite and end-stage renal disease in licensed pesticide applicators and spouses in the Agricultural Health Study. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2024; 34:322-332. [PMID: 38191926 PMCID: PMC11142909 DOI: 10.1038/s41370-023-00625-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 01/10/2024]
Abstract
BACKGROUND Nitrate and nitrite ingestion has been linked to kidney cancer, possibly via the endogenous formation of carcinogenic N-nitroso compounds. These exposures might also contribute to end-stage renal disease (ESRD). OBJECTIVES We investigated associations of drinking water nitrate and dietary nitrate and nitrite intakes (total and by food type) with incident ESRD in the Agricultural Health Study. We also explored modifying effects of vitamin C and heme iron intake, which may affect endogenous nitrosation. METHODS We performed complete case analyses among private pesticide applicators and their spouses. We obtained water nitrate estimates for participants whose primary drinking water source at enrollment (1993-1997) was public water supplies (PWS) or private wells (N = 59,632). Average nitrate concentrations were computed from historical data for PWS users and predicted from random forest models for private well users. Analysis of dietary nitrate and nitrite was restricted to the 30,177 participants who completed the NCI Dietary History Questionnaire during follow-up (1999-2003). Incident ESRD through 2018 was ascertained through linkage with the U.S. Renal Data System. We estimated adjusted hazard ratios (HRs) and 95%CI for associations of tertiles (T) of exposure with ESRD overall and explored effects in strata of vitamin C and heme iron intake. RESULTS We identified 469 incident ESRD cases (206 for dietary analysis). Water nitrate and total dietary nitrate/nitrite were not associated with ESRD, but increased ESRD was associated with nitrate and nitrite from processed meats. We found apparent associations between nitrite and ESRD only among participants with vitamin C SIGNIFICANCE ESRD incidence was associated with dietary nitrate/nitrite from processed meat among all study participants and with total dietary nitrite among participants with lower vitamin C or higher heme iron intake. IMPACT STATEMENT There are few well-established environmental risk factors for end-stage renal disease (ESRD), a worldwide public health challenge. Ingestion of nitrate and nitrite, which may lead to endogenous formation of carcinogenic N-nitroso compounds, has been linked to some cancers and chronic diseases. We investigated these exposures in relation to ESRD in an agricultural cohort. ESRD incidence was associated with dietary nitrate/nitrite from processed meat and with total dietary nitrite among subgroups with lower vitamin C or higher heme iron intake. This study provides preliminary evidence that points to dietary nitrite and possibly dietary nitrate intake as a potential contributor to ESRD.
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Affiliation(s)
- Dazhe Chen
- Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
| | - Christine G Parks
- Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
| | - Laura E Beane Freeman
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
| | - Jonathan N Hofmann
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
| | - Rashmi Sinha
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
| | - Jessica M Madrigal
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
| | - Mary H Ward
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD, USA
| | - Dale P Sandler
- Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA.
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