Soil risk assessment of heavy metal
Cadmium; (c) Lead; (d) Nickel
Figure 3. Risk assessment maps of (a) Chromium; (b) Cadmium; (c) Lead; (d) Nickel
field situated in the middle of the centre of the
exceed the corresponding maximum permissible
study area. Evaluation indices resulting from cross-
limits (MPL) are produced. Figure (3a−d) shows the
validation of spatial maps of soil properties (Table 3)
indicator kriged probability maps of soil Cr, Cd, Pb
forallthesoilheavymetalsthepredictionofgoodness
and Ni based on the concentrations to exceed the
(G) value was greater than zero, which indicates that
respective FAO (2000) MPL value of 100, 3, 50 and 30
spatial prediction using semivariogram parameters
mg kg −1 , respectively. It was seen that whole study
is better than assuming mean of observed value as the
area has higher than 0.99% probability to exceed this
values for any unsampled location. This also shows
MPL value of Pb. About 10% area of the study site
that semivariogram parameters obtained from fitting
was having higher concentration than MPL value of
of experimental semivariogram values were fairly
Cd and Ni concentrated at the centre and north-west
reasonable to describe the spatial variation.
corner of the study area, respectively.
In order to obtain data that may be used in the future
Conclusion
for the assessment of the health risk due to elevated
soil heavy metals concentration in cultivated areas,
Geostatistics and statistics have been employed for
spatial maps of the probability that these pollutants
assessment and mapping of soil pollution in the
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