Study on Nitrogen, Phosphor and Chemical Oxygen Demand of Differnt Categories of Aquaculture Lakes by Means of Principal Component Analysis, Factor Analysis and Cluster Analysis

Abstract

The author measured TN, NH4+-N, NO2--N, NO3--N, TP, PO43--P and CODMn of the five aquaculture lakes that is, Liangzi Lake, Futou Lake, Chaipo Lake, Nanhu Lake and Yezhi Lake, in Wuhan in 2007, and had analyzed the results by means of Principal Component Analysis (PCA), Factor Analysis (FA) and Cluster Analysis (CA). The PCA result showed that the two principal components were nutrient factor (including TN, NO2--N, NO3--N, TP, PO43--P and CODMn) and ammonium absorption factor (NH4+-N), with their function expression integrated. The results of FA and PCA were in conformity, with their factor score function expression integrated. R-mode cluster result indicated that the seven hydrochemical indexes could be divided into four categories, i.e. NO3 - -N, TP, TN and NO2--N make up of one category, and another three categories were PO43--P, NH4+-N and CODMn, respectively. Q-mode cluster result showed that the five lakes can be divided into two categories, Futou Lake and Liangzi Lake is one category, and Chaipo Lake, Yezhi Lake and Nanhu Lake is the other, which has been caused by urban waste water, domestic sewage and aquaculture production.