IMPACT OF CADMIUM ON THE MUMMICHOG FUNDULUS-HETEROCLITUS AND THE ROLE OF CALCIUM IN SUPPRESSING HEAVY-METAL TOXICITY

1. Freshwater adapted mummichogs (Fundulus heteroclitus) were exposed to cadmium. In soft water (less-than-or-equal-to 5 mg/l CaCO3), the 4-day safe (TL100) and sublethal (TL50) tolerance limits (TLs) for cadmium were 0. 14-mu-g/l and 12.2-mu-g/l, respectively. 2. Survival declined with increasing cadmium concentration and the length of exposure. The toxicity of cadmium was reduced in water with high calcium concentration (200 mg/l CaCO3). Pre-exposure to calcium also prolonged the survival in cadmium-containing water. 3. The mummichog appears to be extremely well suited for monitoring environmental cadmium poisoning.