Toxic action, main phases

Figure 2.8 The main phases of toxic action. Reproduced from Aliens (1984, p. 433) by courtesy of Marcel Dekker, Inc., New York.

When an organism is placed in an aqueous solution of a toxicant, pseudo-steady-state partitioning takes place between the toxic site of action and the aqueous phase. For organisms in which air is extracted from the water by means of gills, exchange of toxicant takes place mainly via this route, and the rate of uptake is controlled by the cross-sectional area, and the rate of blood flow across the gills. 

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