The Nitrate Nitrogen in Groundwater of Intensive Agricultural Region in Pinggu District by Sampling and Monitoring for 12 Years

Abstract

The nitrate nitrogen of groundwater samples which sampled 24 times from 2006 to 2017 in the intensive agricultural region of Pinggu district in Beijing were analyzed in this study, in order to investigate its dynamic change and important influence factors of this region. The results indicated that the mean value of nitrate nitrogen in groundwater of this region was 6.23 mg/L, which had reached the third level of the national groundwater quality standard, and the annual nitrate nitrogen concentration in groundwater of the region tended to increase. The significant positive correlations between the annual average concentrations of nitrate nitrogen in groundwater and the statistical data of livestock and poultry products from 2006 to 2015 implied that the impact of livestock and poultry industry on the nitrate in groundwater should not be ignored in the region. The increase of precipitation has a trend of increasing the difference of nitrate in groundwater in Pinggu district. The nitrate nitrogen in groundwater sampled from orchard was markedly higher than which from grain field and vegetable field. Samples from deeper well (WD3) always locatd in mountainous area, their nitrate nitrogen was significantly higher than which from spring well (WD1) and well with 30 to 100 m depth (WD2).