QSAR modeling of phys-chem properties: Koc, WSol, VP, H, etc.
The partitioning of pesticides into different environmental compartments and the dangerous leaching in ground-water depends mainly on the physico-chemical properties. The combination of two multivariate approaches (Principal Component Analysis and Hierarchical Cluster Analysis) and CART (Classification and Regression Tree) model was used to rank and classify pesticides of various chemical categories according to their distribution tendency in various media. A Leaching Index (LIN) and a Volatility Index (VIN) have been also proposed and modeled by MLR. The soil sorption coefficient, expressed as the ratio between chemical concentration in soil and in water, normalized to organic carbon (Koc), an important parameter when studying soil mobility and environmental distribution of chemicals, has been also modeled by externally validated highly predictive regression models, based on few simple molecular descriptors.[JMGM, 2007:Most cited paper in Computer Science]
In addition to Koc modelling, other common physico-chemical properties have been successfully modeled by combining different kinds of theoretical molecular descriptors: the basic physico-chemical properties of organic solvents, PCBs, esters, flame retardants, perfluorinated compounds, triazoles (these 3 last classes in the CADASTER Project). The environmental distribution based on phys chem. properties and multivariate analysis by PCA is studied also for PFCs and (benzo) triazoles in the EU-FP7 Project CADASTER. A general classification of 152 organic solvents has been also proposed by applying k-nearest neighbour method and counter-propagation artificial neural network (CP-ANN), in particular Kohonen Maps.
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