An assessment of water quality from a reach of Bailongjiang River, Gansu province

The water quality of a reach of Bailongjiang River, Jialingjiang river basin in Wuwei of Gansu province were evaluated mainly on the basis of fifty four samples collected from three locations. The purposes of the study were to assess the levels of parameters associated with the demands of the functions of the water body and to compare them with Environmental Quality Standards for Surface Water. Water quality parameters included pH, Temperature, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), permanganate index, Total Nitrogen (TN), Total Phosphorus (TP), and NH₃-N were analyzed. Most of the water quality parameters met the Class II level of Environmental Quality Standards for Surface Water. As can be seen from the indexes, the water quality of the river reach can well satisfy the functions of the water body. It is recommended that priority in future projects more attention should be given to the non-linear relationships among parameters that are characteristic of ecosystems. Spatial and temporal distribution of the parameters should be given more attention.