Analysis of TDS Monitoring Results in Drinking Water in Inner Mongolia Autonomous Region, China, 2019

Objective To analyze the monitoring results of total dissolved solids (TDS) in drinking water in Inner Mongolia Autonomous Region, China, 2019.

Methods Based on the monitoring result of TDS in drinking water in 12 cities and 103 counties or districts in Inner Mongolia, 2019, we analyzed the influence on TDS of water periods (dry season or wet season), water supply regions (rural or urban region), water source types (surface water or groundwater), water sample types (finished water, terminal water), being disinfected or not, and treatment method (conventional treatment, only disinfection, only filtration and sedimentation, or being untreated).

Results In 2019, 7 169 water samples were monitored, and the overall pass rate of TDS was 98.24% (7 043/7 169). There was no significant difference in TDS between dry and wet seasons (Z=1.260, P>0.05). TDS was significantly higher in rural water than in urban water (Z=-6.848, P < 0.01), and in surface water than in groundwater (Z=4.001, P < 0.01). TDS showed significant differences between finished water and terminal water (H=6.434, P < 0.05) and between different treatment methods (Z=141.404, P < 0.01). TDS in non-disinfected water was significantly higher than that in disinfected water (Z=8.163, P < 0.01). Chloride, sulfate, and total hardness were positively correlated with TDS (P < 0.01).

Conclusion TDS in Inner Mongolia is generally acceptable. TDS can be affected by water supply regions, water source types, water sample types, and treatment methods. It is correlated with chloride, sulfate, and total hardness.