Hydrocarbons chlorinated, BCFs

To a first approximation, bioconcentration can be considered as the partitioning of a chemical between an organism and the surrounding aqueous milieu. It is therefore not surprising that many studies have been made of the relationship between BCF and the partition coefficient. Some such studies have involved specific chemical classes such as chlorinated polycyclic hydrocarbons (Schiiiirmann and Klein, 1988) and anilines (Zok et al., 1991), but a good number have involved diverse chemicals. There is considerable divergence in the correlations reported, which probably reflects differences in test conditions as mentioned (vide ultra) by Nendza (1998). Nendza (1991) cited six QSARs of the form ... 

Halons (I.e. BCF and BTM) are compounds of fluorine, chlorine and/or bromine with hydrocarbons such as methane and ethane their extinguishing action is also due to negative catalysis. ... 

The formation of macromolecular adducts could be partly responsible for the increase in depuration half-life observed following increased periods of exposure of molluscs to the xenobiotic, particularly for PAH and other hydrocarbons (see Sect. 7.1). The process of adduct formation, and presumably excision and release, could therefore represent, or contribute to, the more stable cellular compartment with a lower rate of xenobiotic turnover postulated by Stegeman and Teal (1973). Similar considerations could contribute to, or explain, the observed tenfold excess in bis(tributyltin) oxide accumulation, compared to that predicted, in M. edulis (Laughlin et al 1986) the preferential retention of PCB with increasing degrees of chlorination (Sect. 7.1) and the higher BCF of PCB compared to those of PAH of similar n-octanol/water partition co-efficients (Pruell et al. 1986). 

Several years ago we demonstrated (Sabijic and Protic 1982b) that the second-order valence molecular connectivity index ( x ) quantitatively correlates with bioconcentration factors (BCFs) of chlorinated hydrocarbons in fish. This result was recently confirmed by two other laboratories (Goverset al. 1984 Koch 1983). The following relationship was established between the index and bioconcentration factors determined by the flow-through method for 20 chlorinated benzenes, biphenyls, diphenyloxides, and similar compounds ... 

FIGURES Observed bioconcentration factors (using flow-through methods) (BCF) in fish plotted as a function of the second-order valence molecular connectivity ( x ) indices of 44 chlorinated hydrocarbons, alkyl and alkenyl benzenes, polycyclic aromatic hydrocarbons, and other similar compounds from TABLE 5. Dotted line corresponds to molecular connectivity model, equation 7. 

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