The Background Values of Ammonia-nitrogen, Total Phosphorus and COD of the Mainstream of Yellow River within Ningxia Province
HOU Kai
YANG Mi
QIAN Hui
LIN Tao
XU Panpan
Abstract：Under standing the background values of ammonia-nitrogen,total phosphorus and COD in the mainstream of Yellow River within Ningxia province is essential to evaluate water contamination in the river basin.Using normal distribution method,relative cumulative frequency and the iterative 2-σ technique,we calculated the background values of the above chemicals based on the data measured from this region in 2013.The results indicated that:①Human activity had the most profound impact on water quality of the river,especially the concentration of ammonia-nitrogen,total phosphorus and COD;② The concentration of ammonia-nitrogen,total phosphorus and COD decreased and the river water was only slightly contaminated;③ The water quality was mainly affected by industrial wastewater,domestic sewage,and drainage from agricultural fields,which are the main pollution sources of the ammonia-nitrogen,phosphorus,and COD;④The normal distribution method and the relative cumulative frequency were tested iteratively using the 2-σ technique,and the result passed the Lilliefors tests of 95％ confidence coefficient.The iterative 2-σ technique is an effective method to calculatethe background values of rivers without noticeable pollution.The results calculated by the three methods and the Environmental Quality Standards for Surface Water found that the background values of ammonia-nitrogen,total phosphorus and COD of the Yellow River mainstream within Ningxia were 0.11～0.31 mg/L,0.03～0.10 mg/L and 7.00～10.10 mg/L respectively.
Keywords：water quality analysisenvironmental background valuerelative cumulative frequencyammonia-nitrogentotal phosphorusCOD
Publication Date：2017-01-01
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：7( 65-71 )