Objective To investigate nitrate pollution of drinking water distributed by centralized treatment systems in rural areas of Yantai City, and analyze pollution sources.
Methods According to Standard sampling and testing methods for drinking water (GB/T 5750-2006), 10 644 samples of finished water and tap water from 3 705 small centralized water supplies in 12 agricultural counties/county-level cities/districts of Yantai City were collected in all dry seasons and wet seasons during the period of 2014-2016.Excel 2003 and SPSS 11.5 were used for statistical analysis on the monitoring results of nitrate.
Results The average concentration of nitrate in drinking er in selected rural areas of Yantai was 26.31 mg/L.According to the limits of nitrate ≤20 mg/L in Drinking water health standards (GB 5749-2006), the unqualified rate of nitrate was 46.91%.There was no difference in the qualified rates of nitrate between dry season (46.93%) and wet season (46.89%) (χ2=0.0015, P>0.05), nor between finished water (46.92%) and tap water (46.89%) (χ2=0.0008, P>0.05).The rural areas with high unqualified rates of nitrate were concentrated in midwest of Yantai.
Conclusion A heavy nitrate pollution of drinking water is identified in rural areas of Yantai city, showing a regional distribution.
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