To explore the influence of different extractant (1 mol/L KC1, 2 mol/L KC1, 4 mol/L KC1 and 0.01 mol/L CaCl2) and ratio of water to sediment (5=1, 10:1, 50:1 and 100= 1) on the determination of extractable nitrogen in sediments from an urban polluted river, surface sediments of Jiuxiang River in Xianlin university town of Nanjing was used in the experiment. Result showed that KG extract nitrogen more effectively than CaCl2. The amount of NH4* -N extracted by KCI and CaCl2 ranged from 312.17 mg/kg to479.23 mg/kg and 177.52 mg/kg to 339.31 mg/kg, respectively, while NO/ -N extracted by them ranged from 4.49 mg/kg to 21.56 mg/kg and 4.25 mg/kg to 8.53 mg/kg, respectively. The amount of extractable nitrogen increased with water-sediment ratios. In the experiment group of 1 mol/L KCI, the extract amount of NH4* -N and NO,~ -N increased by 41.97% and 187.08% when the ratio of water to sediment ranged from 5= 1 to 100:1, respectively. The amount of NH4* -N extracted increased with higher extractant concentrations, while NO3~ -N decreased with lower ones. The experiment suggested that 1 mol/L KCI as extractant and the water-sediment ratio of 100:1 make a better combination when using for extracting NH4* -N and NO3" -N from the urban river sediment.%以城市污染河道——南京仙林大学城九乡河表层沉积物为研究对象,探讨沉积物常用提取剂(1 mol/L KCl、2 mol/L KCl、4 mol/L KCl和0.01 mol/L CaCl2)在不同液土比(5∶1、10∶ 1、50∶1和100∶1)条件下,对城市污染河道沉积物可提取态氮(NH4+-N、NO3--N)测定的影响.结果表明:KCl的提取效果要优于CaCl2,二者NH4+-N提取量分别为312.17 ～479.23、177.52 ～339.31 mg/kg,NO3--N提取量分别为4.49 ～21.56、4.25 ～8.53 mg/kg;可提取态氮提取量随液土比增高而增大,其中1 mol/L KCl组,液土比100∶1时NH4+-N和NO3--N提取量分别比液土比5∶1时增加41.97％和187.08％；NH+4-N提取量随提取剂浓度增高而增大,NO3--N随提取剂浓度增高而降低；采用1 mol/L KCl提取剂、液土比100∶1的组合联合提取城市污染河道沉积物中的NH4+-N、NO3--N,提取效果较好.
展开▼
