Use the Faces Graph to Evaluate Heavy Metal Pollution in Sediment at Benxi Section of Taizi River
J1A Zhenbang, WANG An (Department of Geography, Peking University)WU Ping (Computer Center of Beijing Agricultural University)ZHANG Baoquan, ZHAO Lihua (Environmental Protection Survey Station of Benxi)
One of the graphical representation of multivariate factors, Chernoff's faces method, is combined with two methods evaluating the heavy metal pollution in sediment and used for checking up on the state of heavy metal pollution in Benxi section of Taizi River.According to the principle that the contents of heavy metals in sediment of a river can indicate the state of heavy metal pollution in the river, 29 samples of sediment are collected from different places of the Benxi section of Taizi River and the contents of seven heavy metal elements, including Cu, Hg, Pb, Cr, Cd, Zn and As, in each of the 29 samples are determined respectively. Then, two methods evaluating the heavy metal pollution, geoaccumulation index method and potential ecological risk index method, are used for calculating and processing the determined data. The both determined data and calculated data are further processed by self-compiled computer program and the corresponding faces are drawn by a printer linked up with a microcomputer. The polluting levels of different heavy metals in each of 29 samples can be directly represented by features on the faces.Tee result of analysis for these data and faces shows that the state of pollution caused by heavy metals in Benxi section of Taizi River is rather serious. According to the degree of the pollution, the sequence of these heavy metals is CuPbHgCdAsZnCr, and the degree of pollution of Cu and Pb has been very serious.