As the careful reader will find out, the physico-chemical data on chemicals mentioned in this book vary. A good example is the K AW of the herbizide atrazine. In the database (Section 11.8) we wrote 7.9·10–8 (Rippen 1996). In the CemoS data base, we have the similar value 7.86·10–8. The latter one is the estimated value that follows from water solubility and vapor pressure. In Table 4.1 we give the value 8.05 · 10–9 (Nirmalakhandan and Speece 1988). This is not to confuse our readers. We as modellers depend on those data, and we cannot decide ourselves which ones are ‘good’ or ‘bad’. So we have a problem. Variations of factor 10 or more can significantly change the results of some simulations. This does not mean that the simulation is wrong, but it is uncertain.
KeywordsPartition Coefficient Molar Mass Water Solubility Data Estimation Bioconcentration Factor
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