Abstract: The six-parameter QSFR (quantitative structure-bioconcentration factor relationship) model of the bioconcentration factor (FBC) was constructed based on valence connectivity index (xi), electrotopological state index (ej), andmolecular electronegativitydistance vector (mk), for 239organic pollutants. The traditional correlation coefficient (R2) and the cross-validation correlation coefficient (Q2) were 0.821 and 0.809, respectively. The result demonstrated that the model was highly reliable and had good predictive ability from the point of view of statistics. From the six parameters of the model, it was known that the dominant influencing factors of bioconcentration factor were the molecular structure fragments: —C—, >C—, —O—, —X, —NH2, and the space factors: the flexibility and the puckered degree of organic pollutant molecules. It may be considered that the induced fit mechanism plays a definite action in the process of biological enrichment. The orthogonal transformation of independent variable did not influence the correlativity of model and could reduce the autocorrelation of independent variable.

Key words: Organic pollutant, Bioconcentration factor, Valence connectivity index, Electrotopological state index, Molecular electronegativity distance vector, Induced fit mechanism, Quantitative structure-property/activity relationship (QSAR)