Fig. 4. Cumulative frequency distributions of estimated critical threshold for Cd concentrations in soils (mg kg^-1) (A) and of estimated probability of exceeding this critical threshold (B). For grassland the probability of exceeding the critical threshold for Cd concentrations in soil is 0.0 nearly everywhere, when the quality standard for Cd in kidney (2.5 mg kg^-1) or in grass (1.0 mg kg^-1) is used to calculate the critical threshold for Cd in soils.