Induction of chromosomal aberrations in fish Boleophthalmus dissumieri after exposure in vivo to mitomycin C and heavy metals mercury, selenium and chromium.

The possibilities were explored of using fish as a cytogenetic model in vivo for the detection of potential mutagens. Boleophthalmus dussumieri (2n = 46, fairly large acrocentric chromosomes), an edible mud-skipper and a widely occurring Goby along the Bombay coast, was chosen as the test species after screening 20 species of fish locally available. I.m. injections of mitomycin C in the dose range of 0.5-2.0 mg/kg body weight resulted in a significant increase in the frequency of aberrations per metaphase compared with the control. A dose-response effect was also evident. The types of aberration observed included chromatid and isochromatid breaks, fragments, rings, exchanges and unclassified markers. A significant increase in the number of gaps was also observed. Clastogenic effects of metals such as Hg, Se and Cr in the form of phenyl mercuric acetate, selenium dioxide and sodium dichromate following direct (i.m. injections) and indirect (dissolved in the aquarial water) exposures were studied. A marked enhancement was noticed in the aberration frequency at most of the dose levels tested. Spontaneous chromosomal aberrations in this species were rather rare and occurred at a rate close to zero. If developed along proper lines, fish could be a useful biological model for studying the teratogenic, carcinogenic and mutagenic effects of environmental chemicals.