Research article Chemical composition of Zamzam water: A comparative study with international standards of drinking water Ahmed F. Donia a , Wael I. Mortada b, * a Nephrology Unit, Urology and Nephrology Center, Mansoura University, Mansoura 35516, Egypt b Clinical Chemistry Laboratory, Urology and Nephrology Center, Mansoura University, Mansoura 35516, Egypt ARTICLE INFO Keywords: Zamzam water Chemical composition International guidelines Health effects ABSTRACT Studies conducted on the chemical composition of Zamzam water are conflicting especially for arsenic. Therefore, the aim of our study is to study the composition of tap and bottled Zamzam water and to compare its quality according to international guidelines of drinking water. Six Zamzam tap water samples as well as one bottled sample were analyzed according to standard methods (APHA) for their chemical constituents (pH, TDS, Na, K, Mg, Ca, Fe, Cu, Zn, Cd, Pb, Mn, Al, As, Cl À , SO 4 À2 , HCO 3 - and PO 4 À3 ). The results were compared to guidelines of WHO and EPA for quality of drinking water. All analyzed parameters were below the maximum allowable limits (MAL) of WHO and EPA (p˃0.05), with the exception of TDS. The average values of TDS (814 mg L À1 in tap zamzam water samples and 812 mg L À1 in bottled sample) were below the MAL of WHO (1000 mg L À1 ) but exceeded the limit that defined by EPA as a non-enforceable guidelines (500 mg L À1 )(p˂0.05). Compared to the collected tap zamzam water samples, bottled sample had significantly lower levels of Na, PO 4 À3 (p˂0.05) and Cu (p˂0.01). The study concluded that Zamzam water has acceptable chemical composition including arsenic, except for TDS that exceeds the high non-enforceable accepted limit according to EPA. 1. Introduction The assessment of existing drinking water resources is interesting topic due to their potential health effects [1, 2]. Zamzam water is a holy water that Muslims use for religious and medicinal purposes. Millions of pilgrims drink it and bring it as a gift for their relatives and friends when they return home. Zamzam water, supplied by the well of Zamzam (Figure 1), is available through taps and containers that are distributed in the Masjid Al Haram in Mecca. Zamzam water is also available in bottled form to facilitate air transportation for pilgrims who want to, as the Saudi government has banned the commercial export of Zamzam water [3, 4, 5]. The Zamzam well is about 30.5 m deep with diameter ranges from 1.08 to 2.66 m. The well is now located in ground floor surrounded by glass plates permitting a clear vision of the inside. The water is with- drawn by electrical pumps to become available in the taps distributed in specific areas in the mosque [6]. In 1976, the American Water Resource Association published the first international article about the chemical composition of Zamzam Water. Other studies were also conducted on this topic, and the results were conflicting, especially with regard to arsenic [7, 8, 9, 10]. Shomar found elevated levels of As, NO 3 - , Ca and K in Zamzam water samples collected by pilgrims after their return from Mecca [8]. In 2011, BBC news inter- estingly announced illegal sale of Zamzam drinking water contaminated with arsenic in the UK shops [11]. Conversely, the Saudi geographical survey states that it has a dedicated center (Zamzam Studies and Research Centre) which analyses and monitors the properties of Zamzam well [3]. Alfadul and Khan [9] confirmed that As concentration was within the acceptable range endorsed by different committees. Al-Barakah et al [10] recorded accepted levels of As and NO 3 - in Zamzam water samples regarding local and international standards. Nevertheless, scientific studies on Zamzam water are scarce [6]. Therefore, we con- ducted this study to explore the chemical composition of Zamzam water. chemical constituent. We analyzed Zamzam water samples for their chemical composition (pH, TDS, Na, K, Mg, Ca, Fe, Cu, Zn, Cd, Pb, Mn, Al, As, Cl À , SO 4 À2 , HCO 3 - and PO 4 À3 ) by the American Public Health Associ- ation (APHA) standard methods and compared these levels with the maximum allowable levels (MAL) defined by World Health Organization (WHO) and Environmental Protection Agency (EPA). This study might add more evidences about safety of Zamzam water which is consumed by millions of Muslims around the world. * Corresponding author. E-mail address: w.mortada@mans.edu.eg (W.I. Mortada). Contents lists available at ScienceDirect Heliyon journal homepage: www.cell.com/heliyon https://doi.org/10.1016/j.heliyon.2021.e06038 Received 28 September 2020; Received in revised form 19 November 2020; Accepted 15 January 2021 2405-8440/© 2021 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Heliyon 7 (2021) e06038