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1H a/b/c - Pesticides, pharmaceuticals, perfluoroalkylated substances, antibiotics (WEP/37) Estimation of pesticide evaporation from soil using a Bayesian type modelling technique. Sørensen, Peter1, Andersen, Helle Vibeke 1, Bossi, Rossana1, Jensen, Niels Otto 2, Mogensen , Betty 1, Løkke, Hans 1, 1 The National Environmental Research Institute, Roskilde, DK, Denmark2 Risø National Laboratory, Roskilde, DK, Denmark ABSTRACT- The presented work will be based on a comprehensive experimental effort done for measuring the evaporation of pesticide active ingredients under full-scale conditions. The list of substances for the investigation is ethofumesate, mecoprop-P, pirimicarb, propachlor and pyrimethanil, which cover a wide range of physico-chemical properties in relation to the evaporation rate. The pesticides were sprayed on bare soil in a circle under field conditions and air concentration samples were taken in the centre of the circle at different heights. For each height of sampling time series were collected during the first week after spraying. Meteorological parameters were also registered during the week of experimentation. By combining the concentration levels and the meteorological parameters it is possible to apply air transport equations for establishing a relationship between the measured concentration levels and the release rate from the soil surface to the air. The resulting estimate of evaporation rate is associated with some degree of uncertainty, which is an important factor to quantify and this will be the topic of the presented work. Statistical methods are combined with the modelling approach to form a link between the experimental uncertainty and the related uncertainty of the evaporation rate estimation. The variability in evaporation rate estimates can either be a result of different environmental conditions or a result of the experimental uncertainty. This investigation will make it possible to determine a kind of "aggregated detection limit" for evaporation estimates. A difference between two evaporation rate estimates needs to be larger than this limit before different environmental conditions can be claimed to exist with significance. Key words: evaporation, pesticide, experiment, modelling |
