Re-entry exposure to pesticide residues have been reported to result in potential health risk . For risk assessment purposes it is therefore essential to characterize the exposure processes. Since especially dermal exposure is important in this context, this requires special attention.Models for re-entry exposure estimates have been developed over the past 10 years Leffingwell 1982. Nigg et al. 1984;Zweig et al. 1985). Recent reviews have considered these issues for greenhouse crops in more detail (Van Hemmen, 1993, Van Hemmen et al., 1995. The basic assumption of the developed models is that exposure results from the transfer of pesticide residue present at the crop during worker activities. More specifically, it was stated that dermal exposure (DE [g/day]) is determined by the amount of transferable residue (expressed as dislodgeable foliar residue DFR [g/m 2 ], a crop and work activity specific-transfer factor (TF [m 2 /hr) and duration of re-entry (T, [hr/day]), which can be expressed in the most genera1 form as:where: DE i = DFR i,t * i = i-th pesticide m = m-th task t = t-th day after application.The transfer factor (TF) is an empirical factor which is assumed to be crop and activity specific but pesticide independent. TF's have been derived from exposure data and data on dislodgeable foliar residue established for a variety of crop activities, and are accepted to be relevant for risk assessment. However, within crop and activities variances of the TF may be substantial (Krieger et al. 1991).The actual dislodgeable foliar residue at time of re-entry is considered to be an important source strength for dermal exposure. The level of actual pesticide residue may differ from the initial amount of DFR depending on the decay rate and the elapsed time since application. The dissipation of the foliar pesticide deposit is considered to be a complex process of environmental factors, metabolism and translocation (foliar penetration and plant growth), and pesticide formulation (Bentson 1990). Willis and McDowell (1987) assumed that the process of decay may in many cases be described by a first order process. Thus, the relationship between initial and actual DFR can be described as: