From: The analysis of groundwater nitrate pollution and health risk assessment in rural areas of Yantai, China
Year
Nitrate nitrogen content (mg/L)
Number of samples
Qualified rate(%)
2015
23.4 ± 18.1
836
48.33
2016
23.2 ± 18.2
400
49.50
2017
27.1 ± 21.1
572
45.80
2018
15.7 ± 14.4
540
51.30
Total
21.9 ± 18.3
2348
48.59