Microbial Monitoring Results of Rural Drinking Water in Harbin from 2013 to 2017

Objective To investigate the microbial indices in rural drinking water in Harbin, China from 2013 to 2017, and to provide a scientific basis for maintaining drinking water safety in rural areas.

Methods The rural drinking water was monitored according to the requirements of the drinking water safety monitoring program in Harbin. The total number of bacterial colonies, total coliform, and heat-resistant coliform bacteria were examined according to the Standard Examination Method for Drinking Water (GB/T 5750-2006), while the water quality was evaluated according to the Standards for Drinking Water Quality (GB 5749-2006).

Results A total of 4 010 water samples were tested from 2013 to 2017. The overall microbial qualified rate was 95.26% (3 820/4 010). There was a significant difference in the overall qualified rate among different years (χ²=120.34, P < 0.01). There were significant differences in the qualified rates for the total number of bacterial colonies, total coliform, and heat-resistant coliform bacteria among different years in 2013-2017 (χ²=107.15, P < 0.01; χ²=70.12, P < 0.01; χ²=84.62, P < 0.01). During the five years, the overall microbial qualified rates in dry and wet seasons were 95.31% (1 911/2 005) and 95.21% (1 909/2 005), respectively. There were significant differences in the overall microbial qualified rates in dry and wet seasons among different years (dry season:χ²=66.02, P < 0.01; wet season:χ²=54.62, P < 0.01). During the five years, the overall microbial passable rates for finished water and terminal piped water were 95.22% (1 794/1 884) and 95.30% (2 026/2 126), respectively. There were significant differences in the overall microbial passable rates for finished water and terminal piped water among different years (finished water:χ²=58.60, P < 0.01; terminal piped water:χ²=61.79, P < 0.01). There was a significant difference in the overall microbial passable rate for untreated drinking water among different years (χ²=128.64, P < 0.01).

Conclusion The rural drinking water in Harbin achieves a satisfactory result for microbial indices monitoring. In order to improve the quality of rural drinking water, domestic sewage and fecal discharges should be further standardized and disinfection of drinking water should be enhanced.