QUANTITATIVE STRUCTURE-ACTIVITY-RELATIONSHIPS FOR THE BIOCONCENTRATION IN FISH OF 7 POLYCHLORINATED DIBENZODIOXINS

Seven different descriptors of the molecular structure of seven polychlorinated dibenzodioxins were calculated and related quantitatively, using bilinear regression models, to a set of bioconcentration and bioaccumulation factors for two fish species, viz. Fathead Minnow (Pimephales promelas) and juvenile Rainbow Trout (Salmo gairdneri), obtained in earlier work. The quantitative structure-activity relationships thus obtained demonstrate a satisfactory statistical significance (r = 0.87 - 0.96) in the case of bioconcentration in Fathead Minnow. A bioconcentration factor of 4.2 is predicted for 2,3,7,8-TCDD in this species. Less satisfactory relationships were obtained for Rainbow Trout (r = 0.65 - 0.74). For the bioaccumulation factors in both species no relationship could be found with the descriptors from this study. The study tentatively indicates that bioconcentration factors of polychlorinated dibenzo-(1,4)dioxins can be predicted from molecular descriptors, provided not only hydrophobicity-related, but also energy-related parameters are taken into account.