Assessment of physical and microbial contamination of drinking water in Sanandaj villages

Document Type : Original Article

Authors
Roya Rahmatzadeh Moghadam 1
Fatemeh Tabrizi 2
1 Department of Environmental Health Engineering, ABRAN Consulting Engineers, Tehran, Iran
2 Water & Wastewater Company Eastern Tehran, Rudehen, Tehran, Iran
10.22034/ehpr.2025.549662.1001
Abstract
Access to safe drinking water is critical for public health, yet rural areas often face contamination challenges. This study aimed to assess the physical and microbial quality of drinking water in 10 villages of Sanandaj city, Iran, to identify contamination risks and inform water management strategies. A stratified random sampling approach was used to collect 400 water samples (100 per quarterly round) from source, storage, and distribution points across wells, springs, and piped systems over 12 months. Samples were analyzed for pH, turbidity, residual chlorine, total coliforms, fecal coliforms, and heterotrophic plate counts (HPC) following standard protocols (APHA, 2017). Results revealed pH values within WHO guidelines (6.5–8.5), but 12% of distribution point samples exceeded the turbidity threshold of 5 NTU, and residual chlorine levels were consistently low (0.12–0.22 mg/L). Microbial contamination was widespread, with total coliforms detected in 82% of samples and fecal coliforms in 55%, particularly at distribution points (16.2 and 4.8 MPN/100 mL, respectively). HPC remained below 500 CFU/mL but increased from source to distribution, suggesting biofilm formation. Summer months showed higher turbidity and fecal coliforms due to runoff and temperature effects. The Water Quality Index classified six villages as “poor” (WQI < 70) and four as “fair” (WQI 70–80), with spring-based systems performing better. These findings highlight inadequate disinfection, aging infrastructure, and environmental vulnerabilities as key contamination drivers. Urgent interventions, including enhanced chlorination, source protection, and pipe maintenance, are needed to ensure safe drinking water and reduce health risks in rural Sanandaj.

Graphical Abstract

Assessment of physical and microbial contamination of drinking water in Sanandaj villages

Highlights

·       Widespread fecal coliform contamination detected in 55% of drinking water samples.

·       Turbidity exceeded WHO limits at distribution points, correlating with microbial counts.

·       Residual chlorine levels consistently below WHO guidelines, indicating poor disinfection.

·       Seasonal peaks in contamination were observed during summer due to runoff and temperature.

·       Water Quality Index classified most villages as "poor" or "fair," none as "good."

Keywords
Drinking Water Quality
Microbial Contamination
Residual Chlorine
Rural Water Supply
Turbidity
Subjects
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Environmental Health and Pollution Research
Volume 1, Issue 1
Winter 2026
Pages 13-20

  • Receive Date 08 October 2025
  • Accept Date 10 December 2025
  • First Publish Date 10 December 2025
  • Publish Date 01 January 2026