Drinking Water Quality and Human Health Patrick Levallois and Cristina Villanueva Belmonte ww.mdpi.com/journal/ijerph Edited by Printed Edition of the Special Issue Published in International Journal of Environmental Research and Public Health Drinking Water Quality and Human Health Drinking Water Quality and Human Health Special Issue Editors Patrick Levallois Cristina Villanueva Belmonte MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade Special Issue Editors Patrick Levallois Institut national de sant ́ e publique du Qu ́ ebec (INSPQ) Canada Cristina Villanueva Belmonte ISGlobal—Barcelona Institute for Global Health Spain Editorial Office MDPI St. Alban-Anlage 66 4052 Basel, Switzerland This is a reprint of articles from the Special Issue published online in the open access journal International Journal of Environmental Research and Public Health (ISSN 1660-4601) from 2017 to 2019 (available at: https://www.mdpi.com/journal/ijerph/special issues/drinking water) For citation purposes, cite each article independently as indicated on the article page online and as indicated below: LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. Journal Name Year , Article Number , Page Range. ISBN 978-3-03897-726-1 (Pbk) ISBN 978-3-03897-727-8 (PDF) Cover image of istock.com/Bartosz Hadyniak. c © 2019 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. The book as a whole is distributed by MDPI under the terms and conditions of the Creative Commons license CC BY-NC-ND. Contents About the Special Issue Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix Patrick Levallois and Cristina M. Villanueva Drinking Water Quality and Human Health: An Editorial Reprinted from: Int. J. Environ. Res. Public Health 2019 , 16 , 631, doi:10.3390/ijerph16040631 1 Rianna T. Murray, Rachel E. Rosenberg Goldstein, Elisabeth F. Maring, Daphne G. Pee, Karen Aspinwall, Sacoby M. Wilson and Amy R. Sapkota Prevalence of Microbiological and Chemical Contaminants in Private Drinking Water Wells in Maryland, USA Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1686, doi:10.3390/ijerph15081686 5 Charles A. Osunla and Anthony I. Okoh Vibrio Pathogens: A Public Health Concern in Rural Water Resources in Sub-Saharan Africa Reprinted from: Int. J. Environ. Res. Public Health 2017 , 14 , 1188, doi:10.3390/ijerph14101188 18 Emily Kumpel, Caroline Delaire, Rachel Peletz, Joyce Kisiangani, Angella Rinehold, Jennifer De France, David Sutherland and Ranjiv Khush Measuring the Impacts of Water Safety Plans in the Asia-Pacific Region Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1223, doi:10.3390/ijerph15061223 45 Zhifei He, Ghose Bishwajit, Dongsheng Zou, Sanni Yaya, Zhaohui Cheng and Yan Zhou Burden of Common Childhood Diseases in Relation to Improved Water, Sanitation, and Hygiene (WASH) among Nigerian Children Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1241, doi:10.3390/ijerph15061241 63 Resoketswe Charlotte Moropeng, Phumudzo Budeli, Lizzy Mpenyana-Monyatsi and Maggy Ndombo Benteke Momba Dramatic Reduction in Diarrhoeal Diseases through Implementation of Cost-Effective Household Drinking Water Treatment Systems in Makwane Village, Limpopo Province, South Africa Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 410, doi:10.3390/ijerph15030410 75 Dorian Tosi Robinson, Ariane Schertenleib, Bal Mukunda Kunwar, Rubika Shrestha, Madan Bhatta and Sara J. Marks Assessing the Impact of a Risk-Based Intervention on Piped Water Quality in Rural Communities: The Case of Mid-Western Nepal Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1616, doi:10.3390/ijerph15081616 92 Pascal Beaudeau A Systematic Review of the Time Series Studies Addressing the Endemic Risk of Acute Gastroenteritis According to Drinking Water Operation Conditions in Urban Areas of Developed Countries Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 867, doi:10.3390/ijerph15050867 115 Damien Mouly, Sarah Goria, Michael Mouni ́ e, Pascal Beaudeau, Catherine Galey, Anne Gallay, Christian Ducrot and Yann Le Strat Waterborne Disease Outbreak Detection: A Simulation-Based Study Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1505, doi:10.3390/ijerph15071505 140 v Pirjo-Liisa Rantanen, Ilkka Mellin, Minna M. Kein ̈ anen-Toivola, Merja Ahonen and Riku Vahala The Seasonality of Nitrite Concentrations in a Chloraminated Drinking Water Distribution System Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1756, doi:10.3390/ijerph15081756 155 Kirstine Wodschow, Birgitte Hansen, J ̈ org Schullehner and Annette Kjær Ersbøll Stability of Major Geogenic Cations in Drinking Water—An Issue of Public Health Importance: A Danish Study, 1980–2017 Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1212, doi:10.3390/ijerph15061212 172 Magali Corso, Catherine Galey, Rene ́ Seux and Pascal Beaudeau An Assessment of Current and Past Concentrations of Trihalomethanes in Drinking Water throughout France Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1669, doi:10.3390/ijerph15081669 188 Keven J. Jean, Nancy Wassef, Fabien Gagnon and Mathieu Valcke A Physiologically-Based Pharmacokinetic Modeling Approach Using Biomonitoring Data in Order to Assess the Contribution of Drinking Water for the Achievement of an Optimal Fluoride Dose for Dental Health in Children Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1358, doi:10.3390/ijerph15071358 201 Mary H. Ward, Rena R. Jones, Jean D. Brender, Theo M. de Kok, Peter J. Weyer, Bernard T. Nolan, Cristina M. Villanueva and Simone G. van Breda Drinking Water Nitrate and Human Health: An Updated Review Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1557, doi:10.3390/ijerph15071557 219 Tarik Benmarhnia, Ianis Delpla, Lara Schwarz, Manuel J. Rodriguez and Patrick Levallois Heterogeneity in the Relationship between Disinfection By-Products in Drinking Water and Cancer: A Systematic Review Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 979, doi:10.3390/ijerph15050979 250 Kirsten S. Almberg, Mary E. Turyk, Rachael M. Jones, Kristin Rankin, Sally Freels and Leslie T. Stayner Atrazine Contamination of Drinking Water and Adverse Birth Outcomes in Community Water Systems with Elevated Atrazine in Ohio, 2006–2008 Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1889, doi:10.3390/ijerph15091889 263 Kuan Y. Chang, I-Wen Wu, Bo-Ruei Huang, Jih-Gau Juang, Jia-Chyi Wu, Su-Wei Chang and Chung Cheng Chang Associations between Water Quality Measures and Chronic Kidney Disease Prevalence in Taiwan Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 2726, doi:10.3390/ijerph15122726 277 Mathieu Valcke, Marie-H ́ el` ene Bourgault, Sami Haddad, Mich` ele Bouchard, Denis Gauvin and Patrick Levallois Deriving A Drinking Water Guideline for A Non-Carcinogenic Contaminant: The Case of Manganese Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1293, doi:10.3390/ijerph15061293 292 Ashley Suchomel, Helen Goeden and Julia Dady A Method for Developing Rapid Screening Values for Active Pharmaceutical Ingredients (APIs) in Water and Results of Initial Application for 119 APIs Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 1308, doi:10.3390/ijerph15071308 308 vi Helen Goeden Focus on Chronic Exposure for Deriving Drinking Water Guidance Underestimates Potential Risk to Infants Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 512, doi:10.3390/ijerph15030512 . . . 330 Minhaz Farid Ahmed, Lubna Alam, Che Abd Rahim Mohamed, Mazlin Bin Mokhtar and Goh Choo Ta Health Risk of Polonium 210 Ingestion via Drinking Water: An Experience of Malaysia Reprinted from: Int. J. Environ. Res. Public Health 2018 , 15 , 2056, doi:10.3390/ijerph15102056 . . . 343 vii About the Special Issue Editors Patrick Levallois, MD, MSc, full clinical professor at Université Laval (Québec, QC, Canada). He is a medical specialist in preventive medicine and public health and a medical adviser at Institut national de santé publique du Québec (INSPQ). He is presently the coordinator of the Water Scientific Group of this institution, dealing with water and health issues and advising different governmental bodies. He has worked for 30 years on issues related to drinking water and health. A tenured professor at Laval until 2017, he taught epidemiology and environmental health and led several important research projects on drinking water quality and health impacts. His work concerns mainly chemical quality (disinfection by-products, nitrates, arsenic, etc.) but also microbiological quality (related to farming activities and climate change). He has worked and conducted research mainly in Québec, QC (Canada) but has developed important international links, principally with US and European partners, researchers, and public health officers. During a sabbatical at the Centre for Research in Environmental Epidemiology (CREAL) (Barcelona), he organized with Cristiana M. Villanueva an international symposium on «Exposure and health effects of chemicals in drinking water». To date, he has published more than 100 papers in scientific journals. h-index: 27 (Scopus), >2400 citations by February 2019). Cristina Villanueva Belmonte, PhD. Associate Research Professor at ISGlobal, Barcelona. She studied Environmental Sciences and completed a PhD in Environmental Epidemiology at the Universitat Aut`onoma de Barcelona (UAB), Spain. She did a post-doc at the National Institute of Health and Medical Research (INSERM) in Rennes (France), and since 2006, she has been a researcher at the Centre for Research in Environmental Epidemiology (CREAL)—now ISGlobal. She has been a lecturer of Environmental Epidemiology to students of Environmental Sciences (UAB), and at the Master of Public Health (UPF-UAB). Currently, she teaches Environmental Health course for the Global Health Master (UB). She is a world-famous expert on water contaminants and their impact on health, including exposure assessment to water contaminants through drinking water and swimming pools (disinfection by-products, nitrate, etc.), the evaluation of the association with health effects (cancer, reproductive outcomes, child health), the understanding of their underlying mechanisms, and the estimation of the burden of disease attributed to chemicals. She leads related research on trihalomethanes in drinking water and burden of disease, the working group on water exposures in the Multi Case Control Study (MCC)—Spain study and in the Infancia y Medio Ambiente (INMA) project, HELIX project, and is part of the research team in the EXPOSOMICS EU project. Her work has resulted in 91 publications in scientific journals (h-index: 30 (Scopus), >1900 citations by February 2019). ix International Journal of Environmental Research and Public Health Editorial Drinking Water Quality and Human Health: An Editorial Patrick Levallois 1,2, * and Cristina M. Villanueva 3,4,5,6 1 Direction de la sant é environnementale et de la toxicologie, Institut national de la sant é publique du Qu é bec, QC G1V 5B3, Canada 2 D é partement de m é decine sociale et pr é ventive, Facult é de m é decine, Universit é Laval, Qu é bec, QC G1V 0A6, Canada 3 ISGlobal, 08003 Barcelona, Spain; cristina.villanueva@isglobal.org 4 Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain 5 Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Carlos III Institute of Health, 28029 Madrid, Spain 6 IMIM (Hospital del Mar Medical Research Institute), 08003 Barcelona, Spain * Correspondence: patrick.levallois@msp.ulaval.ca Received: 12 February 2019; Accepted: 19 February 2019; Published: 21 February 2019 Drinking water quality is paramount for public health. Despite improvements in recent decades, access to good quality drinking water remains a critical issue. The World Health Organization estimates that almost 10% of the population in the world do not have access to improved drinking water sources [ 1 ], and one of the United Nations Sustainable Development Goals is to ensure universal access to water and sanitation by 2030 [ 2 ]. Among other diseases, waterborne infections cause diarrhea, which kills nearly one million people every year. Most are children under the age of five [ 1 ]. At the same time, chemical pollution is an ongoing concern, particularly in industrialized countries and increasingly in low and medium income countries (LMICs). Exposure to chemicals in drinking water may lead to a range of chronic diseases (e.g., cancer and cardiovascular disease), adverse reproductive outcomes and effects on children’s health (e.g., neurodevelopment), among other health effects [3]. Although drinking water quality is regulated and monitored in many countries, increasing knowledge leads to the need for reviewing standards and guidelines on a nearly permanent basis, both for regulated and newly identified contaminants. Drinking water standards are mostly based on animal toxicity data, and more robust epidemiologic studies with an accurate exposure assessment are rare. The current risk assessment paradigm dealing mostly with one-by-one chemicals dismisses potential synergisms or interactions from exposures to mixtures of contaminants, particularly at the low-exposure range. Thus, evidence is needed on exposure and health effects of mixtures of contaminants in drinking water [4]. In a special issue on “Drinking Water Quality and Human Health” IJERPH [ 5 ], 20 papers were recently published on different topics related to drinking water. Eight papers were on microbiological contamination, 11 papers on chemical contamination, and one on radioactivity. Five of the eight papers were on microbiology and the one on radioactivity concerned developing countries, but none on chemical quality. In fact, all the papers on chemical contamination were from industrialized countries, illustrating that microbial quality is still the priority in LMICs. However, chemical pollution from a diversity of sources may also affect these settings and research will be necessary in the future. Concerning microbiological contamination, one paper deals with the quality of well water in Maryland, USA [ 6 ], and it confirms the frequent contamination by fecal indicators and recommends continuous monitoring of such unregulated water. Another paper did a review of Vibrio pathogens, which are an ongoing concern in rural sub-Saharan Africa [ 7 ]. Two papers focus on the importance of global primary prevention. One investigated the effectiveness of Water Safety Plans (WSP) Int. J. Environ. Res. Public Health 2019 , 16 , 631 1 www.mdpi.com/journal/ijerph Int. J. Environ. Res. Public Health 2019 , 16 , 631 implemented in 12 countries of the Asia-Pacific region [ 8 ]. The other evaluated the lack of intervention to improve Water, Sanitation and Hygiene (WASH) in Nigerian communities and its effect on the frequency of common childhood diseases (mainly diarrhea) in children [ 9 ]. The efficacies of two types of intervention were also presented. One was a cost-effective household treatment in a village in South Africa [ 10 ], the other a community intervention in mid-western Nepal [ 11 ]. Finally, two epidemiological studies were conducted in industrialized countries. A time-series study evaluated the association between general indicators of drinking water quality (mainly turbidity) and the occurrence of gastroenteritis in 17 urban sites in the USA and Europe. [ 12 ] The other evaluated the performance of an algorithm to predict the occurrence of waterborne disease outbreaks in France [ 13 ]. On the eleven papers on chemical contamination, three focused on the descriptive characteristics of the contamination: one on nitrite seasonality in Finland [ 14 ], the second on geogenic cation (Na, K, Mg, and Ca) stability in Denmark [ 15 ] and the third on historical variation of THM concentrations in french water networks [ 16 ]. Another paper focused on fluoride exposure assessments using biomonitoring data in the Canadian population [ 17 ]. The other papers targeted the health effects associated with drinking water contamination. An extensive up-to-date review was provided regarding the health effects of nitrate [ 18 ]. A more limited review was on heterogeneity in studies on cancer and disinfection by-products [ 19 ]. A thorough epidemiological study on adverse birth outcomes and atrazine exposure in Ohio found a small link with lower birth weight [ 20 ]. Another more geographical study, found a link between some characteristics of drinking water in Taiwan and chronic kidney diseases [ 21 ]. Finally, the other papers discuss the methods of deriving drinking water standards. One focuses on manganese in Quebec, Canada [ 22 ], another on the screening values for pharmaceuticals in drinking water, in Minnesota, USA [ 23 ]. The latter developed the methodology used in Minnesota to derive guidelines—taking the enhanced exposure of young babies to water chemicals into particular consideration [ 24 ]. Finally, the paper on radioactivity presented a description of Polonium 210 water contamination in Malaysia [25]. In conclusion, despite several constraints (e.g., time schedule, fees, etc.), co-editors were satisfied to gather 20 papers by worldwide teams on such important topics. Our small experience demonstrates the variety and importance of microbiological and chemical contamination of drinking water and their possible health effects. Author Contributions: P.L. wrote a first draft of the editorial and approved the final version. C.M.V. did a critical review and added important complementary information to finalize this editorial. Funding: This editorial work received no special funding. Acknowledgments: Authors want to acknowledge the important work of the IJERPH staff and of numbers of anonymous reviewers. Conflicts of Interest: The authors declare no conflict of interest. References 1. WHO/UNICEF Drinking-Water. Available online: https://www.who.int/news-room/fact-sheets/detail/ drinking-water (accessed on 11 February 2019). 2. United Nations Clean Water and Sanitation. Available online: https://www.un.org/sustainabledevelopment/ water-and-sanitation/ (accessed on 12 February 2019). 3. Villanueva, C.M.; Kogevinas, M.; Cordier, S.; Templeton, M.R.; Vermeulen, R.; Nuckols, J.R.; Nieuwenhuijsen, M.J.; Levallois, P. Assessing Exposure and Health Consequences of Chemicals in Drinking Water: Current State of Knowledge and Research Needs. Environ. Health Perspect. 2014 , 122 , 213–221. [CrossRef] [PubMed] 4. Villanueva, C.M.; Levallois, P. Exposure Assessment of Water Contaminants. In Exposure Assessment in Environmental Epidemiology ; Nieuwenhuijsen, M.J., Ed.; Oxford University Press: New York, NY, USA, 2015; pp. 329–348. ISBN 978-0-19-937878-4. 5. IJERPH|Special Issue: Drinking Water Quality and Human Health. Available online: https://www.mdpi. com/journal/ijerph/special_issues/drinking_water (accessed on 11 February 2019). 2 Int. J. Environ. Res. Public Health 2019 , 16 , 631 6. Murray, R.T.; Rosenberg Goldstein, R.E.; Maring, E.F.; Pee, D.G.; Aspinwall, K.; Wilson, S.M.; Sapkota, A.R. Prevalence of Microbiological and Chemical Contaminants in Private Drinking Water Wells in Maryland, USA. Int. J. Environ. Res. Public Health 2018 , 15 , 1686. [CrossRef] [PubMed] 7. Osunla, C.A.; Okoh, A.I. Vibrio Pathogens: A Public Health Concern in Rural Water Resources in Sub-Saharan Africa. Int. J. Environ. Res. Public Health 2017 , 14 , 1188. [CrossRef] [PubMed] 8. Kumpel, E.; Delaire, C.; Peletz, R.; Kisiangani, J.; Rinehold, A.; De France, J.; Sutherland, D.; Khush, R. Measuring the Impacts of Water Safety Plans in the Asia-Pacific Region. Int. J. Environ. Res. Public Health 2018 , 15 , 1223. [CrossRef] [PubMed] 9. He, Z.; Bishwajit, G.; Zou, D.; Yaya, S.; Cheng, Z.; Zhou, Y. Burden of Common Childhood Diseases in Relation to Improved Water, Sanitation, and Hygiene (WASH) among Nigerian Children. Int. J. Environ. Res. Public Health 2018 , 15 , 1241. [CrossRef] [PubMed] 10. Moropeng, R.C.; Budeli, P.; Mpenyana-Monyatsi, L.; Momba, M.N.B. Dramatic Reduction in Diarrhoeal Diseases through Implementation of Cost-Effective Household Drinking Water Treatment Systems in Makwane Village, Limpopo Province, South Africa. Int. J. Environ. Res. Public Health 2018 , 15 , 410. [CrossRef] [PubMed] 11. Tosi Robinson, D.; Schertenleib, A.; Kunwar, B.M.; Shrestha, R.; Bhatta, M.; Marks, S.J. Assessing the Impact of a Risk-Based Intervention on Piped Water Quality in Rural Communities: The Case of Mid-Western Nepal. Int. J. Environ. Res. Public Health 2018 , 15 , 1616. [CrossRef] [PubMed] 12. Beaudeau, P. A Systematic Review of the Time Series Studies Addressing the Endemic Risk of Acute Gastroenteritis According to Drinking Water Operation Conditions in Urban Areas of Developed Countries. Int. J. Environ. Res. Public Health 2018 , 15 , 867. [CrossRef] [PubMed] 13. Mouly, D.; Goria, S.; Mouni é , M.; Beaudeau, P.; Galey, C.; Gallay, A.; Ducrot, C.; Le Strat, Y. Waterborne Disease Outbreak Detection: A Simulation-Based Study. Int. J. Environ. Res. Public Health 2018 , 15 , 1505. [CrossRef] [PubMed] 14. Rantanen, P.-L.; Mellin, I.; Keinänen-Toivola, M.M.; Ahonen, M.; Vahala, R. The Seasonality of Nitrite Concentrations in a Chloraminated Drinking Water Distribution System. Int. J. Environ. Res. Public Health 2018 , 15 , 1756. [CrossRef] [PubMed] 15. Wodschow, K.; Hansen, B.; Schullehner, J.; Ersbøll, A.K. Stability of Major Geogenic Cations in Drinking Water—An Issue of Public Health Importance: A Danish Study, 1980–2017. Int. J. Environ. Res. Public Health 2018 , 15 , 1212. [CrossRef] [PubMed] 16. Corso, M.; Galey, C.; Seux, R.; Beaudeau, P. An Assessment of Current and Past Concentrations of Trihalomethanes in Drinking Water throughout France. Int. J. Environ. Res. Public Health 2018 , 15 , 1669. 17. Jean, K.J.; Wassef, N.; Gagnon, F.; Valcke, M. A Physiologically-Based Pharmacokinetic Modeling Approach Using Biomonitoring Data in Order to Assess the Contribution of Drinking Water for the Achievement of an Optimal Fluoride Dose for Dental Health in Children. Int. J. Environ. Res. Public Health 2018 , 15 , 1358. [CrossRef] [PubMed] 18. Ward, M.H.; Jones, R.R.; Brender, J.D.; De Kok, T.M.; Weyer, P.J.; Nolan, B.T.; Villanueva, C.M.; Van Breda, S.G. Drinking Water Nitrate and Human Health: An Updated Review. Int. J. Environ. Res. Public Health 2018 , 15 , 1557. [CrossRef] [PubMed] 19. Benmarhnia, T.; Delpla, I.; Schwarz, L.; Rodriguez, M.J.; Levallois, P. Heterogeneity in the Relationship between Disinfection By-Products in Drinking Water and Cancer: A Systematic Review. Int. J. Environ. Res. Public Health 2018 , 15 , 979. [CrossRef] [PubMed] 20. Almberg, K.S.; Turyk, M.E.; Jones, R.M.; Rankin, K.; Freels, S.; Stayner, L.T. Atrazine Contamination of Drinking Water and Adverse Birth Outcomes in Community Water Systems with Elevated Atrazine in Ohio, 2006–2008. Int. J. Environ. Res. Public Health 2018 , 15 , 1889. [CrossRef] [PubMed] 21. Chang, K.Y.; Wu, I.-W.; Huang, B.-R.; Juang, J.-G.; Wu, J.-C.; Chang, S.-W.; Chang, C.C. Associations between Water Quality Measures and Chronic Kidney Disease Prevalence in Taiwan. Int. J. Environ. Res. Public Health 2018 , 15 , 2726. [CrossRef] [PubMed] 22. Valcke, M.; Bourgault, M.-H.; Haddad, S.; Bouchard, M.; Gauvin, D.; Levallois, P. Deriving A Drinking Water Guideline for A Non-Carcinogenic Contaminant: The Case of Manganese. Int. J. Environ. Res. Public Health 2018 , 15 , 1293. [CrossRef] [PubMed] 3 Int. J. Environ. Res. Public Health 2019 , 16 , 631 23. Suchomel, A.; Goeden, H.; Dady, J. A Method for Developing Rapid Screening Values for Active Pharmaceutical Ingredients (APIs) in Water and Results of Initial Application for 119 APIs. Int. J. Environ. Res. Public Health 2018 , 15 , 1308. [CrossRef] [PubMed] 24. Goeden, H. Focus on Chronic Exposure for Deriving Drinking Water Guidance Underestimates Potential Risk to Infants. Int. J. Environ. Res. Public Health 2018 , 15 , 512. [CrossRef] [PubMed] 25. Ahmed, M.F.; Alam, L.; Mohamed, C.A.R.; Mokhtar, M.B.; Ta, G.C. Health Risk of Polonium 210 Ingestion via Drinking Water: An Experience of Malaysia. Int. J. Environ. Res. Public Health 2018 , 15 , 2056. [CrossRef] [PubMed] © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). 4 International Journal of Environmental Research and Public Health Article Prevalence of Microbiological and Chemical Contaminants in Private Drinking Water Wells in Maryland, USA Rianna T. Murray 1 , Rachel E. Rosenberg Goldstein 1,2 , Elisabeth F. Maring 3 , Daphne G. Pee 4 , Karen Aspinwall 4 , Sacoby M. Wilson 1 and Amy R. Sapkota 1, * 1 Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, 4200 Valley Drive, College Park, MD 20742, USA; rmurray@umd.edu (R.T.M.); rerosenb@umd.edu (R.E.R.G.); swilson2@umd.edu (S.M.W.) 2 Department of Agricultural & Resource Economics, College of Agriculture & Natural Resources, University of Maryland, 2200 Symons Hall, 7998 Regents Drive, College Park, MD 20742, USA 3 Department of Family Science, University of Maryland School of Public Health, 4200 Valley Drive, College Park, MD 20742, USA; efmaring@umd.edu 4 University of Maryland Extension, University of Maryland, 2200 Symons Hall, 7998 Regents Drive, College Park, MD 20742, USA; dpee@umd.edu (D.G.P.); Karen@cattailcompany.com (K.A.) * Correspondence: ars@umd.edu; Tel.: +1-301-405-1772 Received: 16 July 2018; Accepted: 3 August 2018; Published: 7 August 2018 Abstract: Although many U.S. homes rely on private wells, few studies have investigated the quality of these water sources. This cross-sectional study evaluated private well water quality in Maryland, and explored possible environmental sources that could impact water quality. Well water samples ( n = 118 ) were collected in four Maryland counties and were analyzed for microbiological and chemical contaminants. Data from the U.S. Census of Agriculture were used to evaluate associations between the presence of animal feeding operations and well water quality at the zip code level using logistic regression. Overall, 43.2% of tested wells did not meet at least one federal health-based drinking water standard. Total coliforms, fecal coliforms, enterococci, and Escherichia coli were detected in 25.4%, 15.3%, 5.1%, and 3.4% of tested wells, respectively. Approximately 26%, 3.4%, and <1% of wells did not meet standards for pH, nitrate-N, and total dissolved solids, respectively. There were no statistically significant associations between the presence of cattle, dairy, broiler, turkey, or aquaculture operations and the detection of fecal indicator bacteria in tested wells. In conclusion, nearly half of tested wells did not meet federal health-based drinking water standards, and additional research is needed to evaluate factors that impact well water quality. However, homeowner education on well water testing and well maintenance could be important for public health. Keywords: private wells; groundwater; drinking water; animal feeding operation; fecal coliforms; enterococci; E. coli ; Maryland 1. Introduction An estimated 44.5 million people in 13 million households across the United States, 14% of the nation’s population, rely on private domestic wells as their primary drinking water source [ 1 , 2 ]. The Safe Drinking Water Act (SDWA) was originally passed by Congress in 1974 to protect public health by regulating the nation’s public drinking water supply and its sources, including rivers, lakes, reservoirs, springs, and groundwater wells [ 3 ]. However, private wells that serve less than 25 people or have less than 15 service connections are neither regulated by the SDWA nor monitored by local regulatory agencies for contaminants that may be associated with adverse human health outcomes [ 3 ]. Int. J. Environ. Res. Public Health 2018 , 15 , 1686 5 www.mdpi.com/journal/ijerph Int. J. Environ. Res. Public Health 2018 , 15 , 1686 The U.S. Environmental Protection Agency (U.S. EPA) and the National Groundwater Association provide guidance to homeowners and recommend testing private wells annually for a number of parameters including total coliform bacteria, nitrates, total dissolved solids (TDS), and pH [ 4 , 5 ]. As this testing is voluntary, little is known about the level or frequency of testing that is performed by private well owners, or about their knowledge and literacy regarding proper well maintenance, testing, and test results. Data on the microbiological and chemical quality of well water are also scarce. Additionally, many homeowners who utilize private water wells may lack the educational and/or financial resources necessary to address water quality issues associated with private water systems [ 6 , 7 ]. The U.S. Centers for Disease Control and Prevention (CDC) recently reported a significant decrease in the annual proportion of reported waterborne disease outbreaks between 1971 and 2006 in public drinking water systems; however, an increase was observed in the annual proportion of outbreaks associated with individual (private) water systems over the same time period [ 8 ]. More recently, a study in North Carolina found that between 2007 and 2013, 99% of emergency department visits for acute gastrointestinal illness caused by microbial contamination of drinking water were associated with private wells [ 9 ]. While the CDC report and the North Carolina study suggest a potential public health issue regarding private wells, the lack of information on private well water quality and monitoring makes it difficult to determine the specific contaminants causing these observed illnesses. Recent studies conducted in Pennsylvania, Virginia, and Wisconsin reported that 40–50% of private wells exceed at least one SDWA health-based standard, most often for coliform bacteria [10–14] These studies and others have demonstrated the influence of factors such as well construction characteristics, local geology, and climatic conditions on private well water quality [ 10 , 12 , 15 – 17 ]. Wallender et al. (2014) evaluated data from the CDC’s Waterborne Disease and Outbreak Surveillance System (WBDOSS) and found that improper design, maintenance, or location of private wells and septic systems contributed to 67% of reported outbreaks from groundwater contamination from 1971 and 2008 [ 18 ]. In Maryland, approximately 19% of the population relies on private wells [ 2 ], however, only one previous study has investigated private well water quality in the state [ 19 ]. Additionally, previous studies have indicated that homeowners generally do not regularly test their private wells or seek technical assistance unless they perceive a water quality problem at the point of use [ 12 , 20 , 21 ], illustrating a need to educate well owners on the importance of monitoring their wells. To address this need, we developed safe drinking water clinics in several Maryland counties. The goals of the clinics were as follows: (1) to educate well owners on proper well maintenance practices and health risks of contaminated wells; (2) to provide well water quality testing in accordance with EPA guidelines; and (3) to characterize the prevalence of microbiological and chemical contaminants in tested wells. After the clinics were completed, we recognized a need to evaluate potential environmental factors that could influence well water quality in Maryland. Recently, Li et al. (2015) investigated microbiological contamination of domestic and community supply wells in California’s Central Valley, a region with intensive animal agriculture [ 22 ]. Approximately 5.9% and 10.3% of wells were positive for generic E. coli and Enterococcus spp., respectively, with significant associations observed between concentrations of enterococci and proximity of wells to animal feeding operations [ 22 ]. In Maryland, there are 12,200 registered farms, including a number of animal feeding operations [ 23 ]. In 2014, the state ranked ninth among U.S. states in broiler chicken production [ 23 ]. Maryland also has dairy and livestock farms, with 49,000 milk-producing cows and another 190,000 beef cattle and calves [ 23 ]. If wells are not properly constructed or maintained, there is potential for surface contaminants from agricultural operations to influence well water quality. As such, we leveraged the well water data collected during the safe drinking water clinics to investigate the possible association between the presence of animal feeding operations and well water quality. 6 Int. J. Environ. Res. Public Health 2018 , 15 , 1686 2. Materials and Methods 2.1. Safe Drinking Water Clinics Between 2012 and 2014, five safe drinking water clinics were held in four Maryland counties: Cecil (two clinics), Kent, Montgomery, and Queen Anne’s (Figure 1, Table 1). Cecil, Kent, and Queen Anne’s counties are located on Maryland’s Eastern Shore (Figure 1), where a large number of homes rely on private wells. The Eastern Shore is highly agricultural and has the highest concentration of animal feeding operations (particularly broiler chicken operations) in the state [ 24 – 26 ]. Montgomery County is also characterized by a large number of homes that rely on private wells; however, there are fewer animal feeding operations in this county. Figure 1. Maryland counties where safe drinking water clinics were held. Table 1. Dates on which the safe drinking water clinics were held. Maryland County Kick-Off Meeting Interpretation Meeting Cecil County I March 2012 May 2012 Kent County October 2012 December 2012 Montgomery February 2013 March 2013 Cecil II September 2013 November 2013 Queen Anne’s February 2014 March 2014 Clinic participants ( n = 150) were recruited at county health fairs, farmers’ markets, and through promotional material on community email listservs and local newspapers. Participants were limited to homeowners in the aforementioned counties with private wells who were interested in participating in the clinics. The safe drinking water clinics were a multi-stage process (Figure 2) that began with a kick-off meeting where registered participants were told of the purpose and significance of the project, provided with water sampling instructions and kits (gloves, two 1 L sterile, polypropylene, wide-mouth Nalgene environmental sampling bottles (Nalgene, Lima, OH, USA) and a large Ziploc bag), and taught how to sample their well water from kitchen or bathroom faucets in accordance with standard protocols. A paper-based survey that was developed by our research and extension teams, and approved by the University of Maryland College Park Institutional Review Board, was also given to participants at the kick-off meetings. The survey included questions on well characteristics, 7 Int. J. Environ. Res. Public Health 2018 , 15 , 1686 homeowner well management practices, prior testing conducted (if any), demographic questions (age, sex, race/ethnicity, and income level), and general health-related questions, including, “In the past month, have you experienced diarrhea?” and “In the past month, have you experienced vomiting?” 3URPRWLRQRI 6DIH'ULQNLQJ :DWHU&OLQLFV E\8QLYHUVLW\ RI0DU\ODQG ([WHQVLRQ 6DIH'ULQNLQJ :DWHU&OLQLF .LFNRII 0HHWLQJ 1LWUDWHVXOIDWH DQGDUVHQLF DQDO\VHV FRQGXFWHGDW WKH0DU\ODQG 'HSDUWPHQWRI +HDOWK/DEV :DWHUVDPSOHV FROOHFWHGE\ KRPHRZQHUV DQGVXUYH\ FRPSOHWHG 0LFURELRORJLFDO DQDO\VHVS+ 7'6WHVWV FRQGXFWHGDW 8QLYHUVLW\RI 0DU\ODQG 6DIH'ULQNLQJ :DWHU&OLQLF )HHGEDFN ,QWHUSUHWDWLRQ 0HHWLQJ D 1 F W K 6 : : ) ,Q 6 : K Figure 2. University of Maryland safe drinking water clinic approach. TDS—total dissolved solids. Participants returned their water samples and completed surveys to their local University of Maryland (UMD) extension office. Samples were kept on ice and transported to the lab within 12 h. Following completion of laboratory analyses (described below), a second follow-up clinic was held where water quality results were returned to participants who provided water samples. The results were individually and confidentially interpreted for participants and potential solutions for wells that did not meet federal standards were discussed where necessary. A follow-up survey was sent to all participants within 12 months after the clinics were conducted to document actions taken by well owners to solve water quality problems or improve the management of their water supply as a result of attending our clinics (data not shown). 2.2. Laboratory Analyses Water samples were analyzed within 24 h of collection for total coliforms, fecal coliforms, E. coli , Enterococcus spp., and Salmonella spp., according to standard U.S. EPA membrane filtration methods [27–30] . Briefly, 100 mL of each sample was filtered through 0.45- μ m, 47-mm mixed cellulose ester filters. The filters were then placed on the appropriate selective media for each microorganism. Membrane- Enterococcus Indoxyl- β - D -Glucoside Agar (mEI) was used for the isolation and enumeration of Enterococcus spp.; MI Agar was used for the isolation and enumeration of both total coliforms and E. coli ; and mFC was used for the isolation and enumeration of fecal coliforms. The mEI plates were incubated at 41 ◦ C for 24 h, mFC plates were incubated at 44.5 ◦ C for 24 h and MI plates were incubated at 37 ◦ C for 24 h. For Salmonella detection, membranes were placed in lactose broth, vortexed vigorously for 3 min, and incubated for 24 h at 37 ◦ C. An aliquot of this enrichment was transferred to TT (tetrathionate) broth base, Hajna; incubated at 37 ◦ C for 24 h; plated on XLT4; and incubated at 37 ◦ C for 24 h. Positive and negative controls were used during each test, and plate counts were performed immediately after incubations. TDS (mg/L) and pH were analyzed using the Pocket Pal TDS Tester and the Stream Survey Test Kit, respectively (Hach Company, Loveland, CO, USA) [ 31 , 32 ]. For nitrate testing, 1 L of each sample was placed into a sterile 1 L polypropylene Nalgene environmental sampling bottle (Nalgene, Lima, OH, USA), 2 mL sulfuric acid solution was added, and the pH was adjusted to <2. For total arsenic testing, 1 L of each sample was placed into a sterile 1 L polypropylene Nalgene environmental sampling bottle (Nalgene, Lima, OH, USA), 2–3 mL of nitric acid solution was added, and the pH was adjusted to <2. The remainder of each water sample was used for sulfate testing. Nitrate and sulfate testing were completed at the Maryland Department of Health (MDH) Labs using an Agilent (Santa Clara, CA, USA) gas chromatograph-mass spectrometer. Nitrate analyses were performed according 8 Int. J. Environ. Res. Public Health 2018 , 15 , 1686 to U.S. EPA Method 353.2, while sulfate analyses were performed according to U.S. EPA Method 375.2 [ 33 , 34]. Total arsenic testing was also completed at the MDH Labs using an Agilent (Santa Clara, CA, USA) inductively-coupled plasma-mass spectrometer per U.S. EPA Method 200.8 [ 35 ]. All quality control/quality assurance approaches recommended by the U.S. EPA methods were employed, including analyses of quality control samples, as well as laboratory reagent blanks and fortified blanks [33–35]. 2.3. Animal Feeding Operations Data We obtained animal feeding operations data from the 2007 U.S. Census of Agricultu