This study consists in the assessment of three radioecological parameters involved in the phenomenological modeling of the plant contamination (interception capacity of the vegetables, root transfer and effective period in soils). The aim is to obtain information about these parameters (if possible regionalized information): range and probability distribution. This study is based on various data sets available, in particular, from long records of radioactivity measurements carried out in France over the period 1960-1980 on leafy vegetables (related to the atmospheric tests of nuclear weapons). The plant contamination equation is fitted from various data sets. As a whole, the different cases studied highlight a bad goodness of fit. Thus, even if the majority of the estimated values for modeling parameters are consistent with literature, they cannot be used to propose regionalized value for radioecological parameters.