Spatial Stationarity

Hi,
I am quite new to R. I want to apply ordinary kriging for the cadmium
level in groundwater (the sample is taken from 60 places in a town)
but before doing this I want to check the spatial stationarity of the
data. I am reading many packages such as spatstat and sp but not
getting how to check whether the data is stationary or not for a
continuous variable. Please help me regarding this.
Adeela