氮在河北平原褐土和地下水迁移转化机制

目的]为了揭示氨氮、亚硝酸盐氮、硝酸盐氮在褐土和地下水中的迁移转化。方法]以河北平原的褐土为主要的研究对象,通过室内土柱的淋滤实验,建立数学模型,预测其迁移规律。结果]在施氮周期内,氨氮浓度最高为15.86 mg/L,最低为0.09 mg/L,平均为2.02 mg/L,超标10.1倍;亚硝酸盐氮最高浓度为37.456 mg/L,最低浓度为0.002 mg/L,平均浓度为4.854 mg/L,超标242.7倍;硝酸盐氮浓度最高为16.35 mg/L,最低浓度为2.12 mg/L,平均浓度为6.51 mg/L的未超标,占标率为32.57%。结论]在浅层地下水中,硝酸盐氮和氨氮是污染地下水的主要2种氮素存在形态。在深层地下水中,氮素主要存在形态为硝酸盐氮。所建数学模型可以定量地预测氮在包气带和地下水中的迁移规律。

Migration and Transformation of Nitrogen in Cinnamon Soil and Groundwater Migration of Hebei Plain

Objective] The research aimed to reveal the migration and the transformation of ammonia nitrogen,nitrite nitrogen and nitrate nitrogen in cinnamon soil and ground water.Method] The soil column leaching test of cinnamon of Hebei Plain was carried out to determine the migration model and predict their migration.Result] The highest amount of ammonia was 15.86 mg/L,the lowest was 0.09 mg/L,and an average was 2.02 mg/L,which exceeded the standard 10.1 times.The highest nitrite concentration was 37.456 mg/L,the lowest was 0.002 mg/L,and an average was 4.854 mg/L,which exceeded the standard 242.7 times.The highest nitrate concentration was 16.35 mg/L,the lowest was 2.12 mg/L,and an average was 6.51 mg/L,which didn’t exceed the standard,and the standard rate was 32.57% in the nitrogen cycle.Conclusion] Nitrate nitrogen and ammonia nitrogen were two main forms of the pollution in the shallow groundwater.The nitrate was primary form of deep groundwater.The mathematical model could be used to build the prediction of nitrogen in the vadose zone and groundwater migration.