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Evaluation of the toxicity of several heavy metals by a fluorescent bacterial bioassay
Author(s) -
Mariscal Alberto,
García Antonio,
Carnero Manuel,
Gómez Jorge,
Pinedo Alfonso,
FernándezCrehuet Joaquín
Publication year - 1995
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.2550150208
Subject(s) - bioassay , toxicant , chemistry , fluorescence , toxicity , escherichia coli , bacterial growth , nuclear chemistry , metal , chromatography , environmental chemistry , incubation , cadmium , bacteria , biochemistry , biology , organic chemistry , genetics , physics , quantum mechanics , gene
This new bioassay determined the toxicity of chemical compounds dissolved in water by measuring the degree of inhibition of the ultraviolet light‐stimulated fluorescence of Escherichia coli in a culture medium in which 4‐methylumbelliferyl β‐D‐glucuronide was the only carbon source. Inhibition produced by one of five heavy‐metal salts (Cd 2+ , Cr 6+ , Hg 2+ , Pb 2+ or Zn 2+ ) was the end‐point and comparison standard to determine the EC 50 and minimum effective concentration (MEC) that produced a decrease of E. coli growth rate, increased doubling time and percentage inhibition and reduced numbers of generations; all these values were derived from the fluorescence signals. Only Cr 6+ and Hg 2+ at two concentrations (0.25 and 0.5 mg I −1 ) almost completely inhibited this E. coli strain. All toxicant concentrations tested produced at least partial inhibitions of growth; Cr 6+ , Hg 2+ and Cd 2+ , in that order, were most toxic, and Pb 2+ the least. Zn 2+ gave higher EC 50 values at 3 h of incubation than at 4 h. The method was simple, rapid and inexpensive and would permit a large number of samples to be tested quickly.