THE TOXICOKINETIC BEHAVIOR OF CHLOROBENZENES IN EARTHWORM (EISENIA-ANDREI) EXPERIMENTS IN SOIL

The toxicokinetic behavior of some chlorobenzenes in earthworms (Eisen ia andrei) kept in soil was studied. To determine elimination kinetics , worms were exposed to chlorobenzenes for 7 d, followed by a depurati on period of 15 or 35 d. Elimination of chlorobenzenes by earthworms k ept in soil was best fitted using a bi-exponential elimination curve. The half-life belonging to the slow phase was in good agreement with m easured elimination half-lives for the same compounds by earthworms ke pt in water. Accumulation of chlorobenzenes in earthworms was studied by exposure over 50 d. Equilibrium was rapidly achieved within 7 d. BA Fs based on the concentration in soil and on the concentration in the interstitial water were calculated. BAFs of 1,2,3,4-tetrachlorobenzene and pentachlorobenzene in earthworms kept in soil and BCFs in earthwo rms kept in water were comparable, demonstrating that uptake proceeds mainly via the interstitial water. For hexachlorobenzene, the BAF was much larger than the BCF, which suggests that intestinal uptake for th is compound is an important complementary route.