As. Jarvis et al., A COMPARISON OF THE AMES ASSAY AND MUTATOX IN ASSESSING THE MUTAGENICPOTENTIAL OF CONTAMINATED DREDGED SEDIMENT, Ecotoxicology and environmental safety, 33(2), 1996, pp. 193-200
The ability of the Ames assay and of Mutatox to identify the genotoxic
potential of dredged sediments was compared. The Ames assay has been
used extensively in the testing of environmental contaminants, whereas
Mutatox, a new bacterial bioluminescence test, has only recently been
used for this purpose. Ten sediments with varying degrees of contamin
ation were soxhlet extracted. Each of the 10 extracts was split with h
alf remaining in a crude form and half cleaned using silica gel chroma
tography, resulting in 20 extract samples. Both the Ames assay (using
Salmonella typhimurium strains TA98 and TA100) and Mutatox were conduc
ted with and without S9 metabolic activation. When metabolically activ
ated, TA98 and TA100 indicated a positive mutagenic response in 80 and
50%, respectively, of the sediment extracts. Without S9 activation, T
A98 indicated a positive mutagenic response with half the extracts, wh
ereas only 10% did so with TA100. Mutatox indicated a positive mutagen
ic response with S9 activation in 75% of the extracts and no mutagenic
response in any of the sediment extracts without metabolic activation
. In a side-by-side comparison of the Ames assay (TA98 with S9) and Mu
tatox, 80% of the sediment extracts had similar responses, both positi
ve and negative. Fifty percent of the sediment extracts had similar re
sponses when tested with TA100 and Mutatox in the presence of S9. Muta
tox compared reasonably well with the Ames assay but was insensitive t
o the presence of direct-acting mutagens in the sediments tested. Alth
ough Mutatox demonstrates promise as a screening tool to assess sedime
nt genotoxicity, the authors consider it appropriate to use the Ames a
ssay as a confirmation for definitive investigations. (C) 1996 Academi
c Press, Inc.