Toxicity of Trace Metal Mixtures to American Flagfish (Jordanella floridae) in Soft, Acidic Water and Implications for Cultural Acidification

Abstract

Laboratory exposures over 1.3 generations showed that trace metal mixtures played a dominant role in the reproductive failure of American flagfish (Jordanella floridae) in soft (6.0 mg .cntdot. L-1 as CaCO3 total hardness), acidified (pH 5.8) water. This finding may also apply for native fish species inhabiting culturally acidified waters. Reproductive failure was complete when pH 5.8 water contained a mixture of Al, Mn, Fe, Ni, Zn, Cu, and Pb at 57% of the concentrations found in acidified waters (or 0.57 ALC). Fry died within 6 d of exposure, adults transferred into the treatment ceased spawning, and hatching of transferred eggs was reduced. The onset of steady spawning activity was delayed by addition of smaller amounts (0.09-0.27 ALC) of metals, but reductions in size of juvenile fish did not persist to maturity. At pH 5.8 with no metals, no effects on any stage of the life cycle were observed. Subsequent testing of fry showed that lethality of a mixture of Al, Zn, and Cu was equivalent to that of all seven metals. The threshold acute LC50 for flagfish fry at pH 5.8 occurred with the simultaneous presence of Al, Zn, and Cu at 29, 5, and 2.3 .mu.g .cntdot. L-1, respectively, or with 95 .mu.g Al .cntdot. L-1 alone. Future research on trace metal stress in culturally acidified waters should consider Zn and Cu, in addition to Al.