The threats of microbial contamination and total dissolved solids in drinking water of Riyadh's rural areas, Saudi Arabia

Abstract

Background: Water is a valuable resource in Saudi Arabia. There are untreated wells scattered throughout villages that are sources of drinking water for some rural residents. Objectives: The present study was conducted to assess the quality of bottled and tap water as well as water from wells in the rural areas of Riyadh, Saudi Arabia. Material and Methods: Water samples (n = 300) were randomly collected from bottles, taps, and wells. Bacteriological examination of samples included total and fecal coliforms. Screening was performed using wet mounts, trichrome stain, and a modified Ziehl–Neelsen technique. Total dissolved salts (TDS) were determined using a conductivity meter. Results: There were no coliforms in samples taken from bottled water, whereas, they were detected in samples taken from tap and well water with percentages of 11%, 30% respectively (p = 0.0001). No fecal coliforms were detected in any of the bottled water samples. However, they were isolated from tap (7%) and well water samples (22%), p = 0.001. Escherichia coli content was found to have the highest percentage distribution compared with other coliforms subtypes in both tap and well water. Parasitological analysis detected only few cysts of Entameba coli in both tap (3%) and well (4%) samples while Giardia lamblia cysts (2%) were only detected in well water. There was a wide variation in concentrations of TDS in the 300 water samples. Chemical analysis of well water showed levels above the maximum limits of Saudi and international recommended standards and guidelines for salinity of drinking water. Conclusion: Water derived from wells in rural areas of Riyadh showed microbial contamination and high total dissolved solids.