Abstract:

The mass concentrations and species of nitrogen and phosphorus in the sediments of Liaohe River and its main tributaries in Jilin Province were analyzed by chemical extraction. The release processes of ammonia nitrogen and dissolved phosphate from the sediments were simulated under laboratory conditions. The results showed that the TN and TP mass contents were higher in the [JP2]sediments of the Yangmu Reservoir and the Tiaozihe River, a Liaohe River tributary (1.09—3.00 g/kg).[JP] The TN and TP mass contents were lower in other sediments of Liaohe River and its tributaries (0.25—0.70 g/kg). The ammonia nitrogen mass content was relatively high in the sediments of the middle and lower reaches of the Yangmu Reservoir (0.044—0.052 g/kg). Caboundp P, organic phosphorus and residual phosphorus were the main forms of TP. The mass concentrations of exchangeable P, Albound P and Febound P were low. Acidic condition promoted the release of ammonia nitrogen and phosphate from the sediments. Alkaline condition  favored
 the release of ammonia nitrogen from the sediments. The release processes were influenced by microbial activities, pH and dissolved oxygen content.

Key words: Liaohe River, sediment, nitrogen, phosphorus, release