This paper reports the results of 96hr acute toxic tests of 4 heavy metalswith the tadpoles of B.viridis Laurenti.The 96ht LC50 values (lethal concen-tration fifty) of silver
copper
mercury and chromiun are 0.29 pPm
1.1 ppm
0.7ppm and 50ppm respectively.The 4 heavy metals are corrosive and make theskins of tedpoles ulcerate or decolourize
in which corrosiveness of silver andcopper is strong.The specific toxic sympton is associated with a particular metal.Because of susceptibity to heavy metals
the tadpoles may be attractive as anassay system to monitor water pollution.