Objective To evaluate nitrate contamination status of drinking water in a county of Hebei Province.
Methods Stratified random sampling method was used to select 100 monitoring spots from 13 villages (towns) in Hebei. Type of water source, mode of water supply, pollution condition of water sources, and covered population were investigated by a self-designed survey form. A total of 354 water samples were collected and tested during the dry season (May) and the rainy season (July) in 2012. All assessments followed the Sanitary Standards for Drinking Water Quality (GB 5749-2006).
Results The average concentration of nitrate in the sampled drinking water was 18.32 mg/L, and 31.64% samples exceeded the sanitary limit for drinking water quality (20 mg/L). The nitrate concentrations and the unqualified rates in finished water & tap water in the dry season were higher than those in the rainy season (P < 0.05). The nitrate concentrations and the unqualified rates in finished water & tap water from the centralized water supply system were lower than that in the reservoir water (non-central water supply) (P < 0.05). The unqualified rate of nitrate concentration was highest in the samples of Shangzhai Town, followed by Bailuquan Town, and all water samples in Shangzhuang town were qualified. In the rainy season, the concentrations and the unqualified rates of nitrate in the regions implementing the safe drinking water project were lower than those without (P < 0.05).
Conclusion The selected county presents severe nitrate contamination in drinking water, and requires a strengthened remediation to control the nitrate pollution.
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