Semivariogram Estimation and Analysis

Semivariograms shall be applied for the characterization of the spatial structure of the data. First, the data have to be tested for normal distribution. The results of the test hypothesis are acceptable for potassium only, in all other cases the hypothesis has to be rejected. After logarithmic transformation of the original data, however, a normal distribution can be obtained. Thus, the following calculations must be performed on the logarithms of the data - only for potassium can the untransformed values be used. 

Element Model Nugget effect Sill Range in km 

B - category for more detailed investigation C - category for investigation in the event of redevelopment 

The element calcium shows a spatial distribution similar to that of lead (Fig. 9-22 d). The locations of the concentration maxima are the same a small maximum has also arisen from the cement and slag mill in the north of the area investigated. There is no index value for calcium because calcium does not rank among the toxic elements. 

The last element to be discussed is potassium. This element shows a completely different spatial distribution (Fig. 9-22 e). The concentration maxima are located in the agricultural areas to the east and the south-west of the region investigated. Increased concentrations cannot be detected in the region of the metallurgical factory. The potassium levels arise as a result of fertilization. 

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