Modeling volatilization of PCDD/F from soil and uptake into vegetation

Soil contamination is one of the long-term environmental problems generated by anthropogenic activities of the last decades. Standards for some organic compounds are being discussed. We investigated the question of whether volatilization of organic chemicals-here PCDD/F-from soil and subsequent sorption to leaves may be a significant pathway for contamination. This transfer pathway is investigated with a mathematical model. The model is based on an analytical solution of the diffusion/dispersion equation for two media and equilibrium assumptions. A calculation is made for 2,3,7,8-TCDD uptake into herbage. It can be shown that this transfer pathway may only be important for highly contaminated soils. The aim of reducing the daily intake of PCDD/F by contaminated food is best reached by an effective emissions control. Volatilization of persistent lipophilic chemicals from the soil is a long-term process and can lead to a secondary pollution of the atmosphere.