EVALUATION OF LEAD(II) AND NICKEL(II) TOXICITY IN NACL AND NACLO4 SOLUTIONS BY USING MICROTOX(R) BIOASSAY

The toxicity of nickel and lead compounds has been evaluated in NaCl a nd NaClO4 solutions by using the Microtox(R) bioassay. The aim of this work was to assess the toxicity of the different species in solution when varying the concentration of the medium. A modified Microtox prot ocol which enables the pH to be constant in all the cuvettes during an alysis has been used. The positively charged species (Ni2+, Pb2+, PbCl +) were found to contribute more to the toxicity of Ni and Ph in NaCl while in NaClO4 solutions free metal was the responsible species. In a ll media studied, Pb compounds were the most toxic and provoked a quic k response of the bacteria.