A Geostatistically Based Probabilistic Risk Assessment Approach - Evolving Application Domains of Data Warehousing and Mining - page 291

Figure 4. a) Probability map of arsenic exceeding the compulsory threshold b) Marginal probability map
of arsenic exceeding the threshold relatively to each area (modif. from Castrignanò et al, 2004)

Figure 5 Contoured map of the risk α (a) and β (b) (modif. from Castrignanò et al, 2004)

Table 1. Marginal proportions of exceeding the critical value of 10 μg/l, relatively to each homogeneous
area (Castrignanò et al, 2004)

Homogeneous Areas N. of Piezometers Samples exceeding threshold Exceedance Proportion

Area 1 18 7 7/18=0.38

Area 2 24 6 7/25=0.24

Area 3 20 5 5/20=0.16

Area 4 20 12 12/20=0.60

Area 5 12 9 9/12=0.75

Σ = 94 Σ = 40