Acute toxicity of cadmium and zinc in the earthworm (Lumbricus terrestris).

Studies are continuing to explore the use of the earthworm (Lumbricus terrestris) for the determination of the acute toxicity of metal compounds. Worms were injected intraperitoneally with cadmium and zinc chlorides, and also zinc chloride followed by cadmium chloride to see if zinc could protect against the toxicity of cadmium. The 48 h acute toxicity (LD50) values were 22 and 23 mg/kg for Cd and Zn respectively and 30 mg/kg for Cd after the worms were pretreated with Zn. It appears that the earthworm can be a useful test subject for obtaining preliminary information on metal toxicity.