Content of Nitrates and Its Influencing Factors in Well Water in Rural Areas of a City, 2014—2019

Objective To investigate the characteristics of nitrate content in well water in rural areas of a city, and to provide a scientific basis for improving rural drinking water quality.

Methods From 2014 to 2019, samples of finished water and terminal water were collected from wells in four rural areas of the city during both dry season and wet season, and the concentration of nitrates was determined. The t-test and an analysis of variance were used to investigate the differences in nitrate concentration after logarithmic transformation among different years, regions, water periods, and types of water source.

Results A total of 2 787 water samples were collected, with a median nitrate concentration of 3.70 mg/L and a rate of reaching the standard of 84.71%. There were significant differences in nitrate concentration among different years, regions, water periods, and types of water source (P < 0.05), with the highest nitrate concentration in 2017 and the lowest nitrate concentration in 2014. For the regions analyzed, the water samples in southeastern regions had a significantly higher nitrate concentration than those in northwest regions; the water samples in wet seasons had a significantly higher nitrate concentration than those in dry seasons; the water samples from shallow wells had a significantly higher nitrate concentration than those from deep wells.

Conclusion Year, region, water period, and type of water source are important influencing factors for nitrate concentration in well water in rural areas of the city. For areas with a high nitrate concentration, priority should be given to the reform of drinking water, and water quality monitoring and water source protection should also be strengthened.