Lethal effects of Mexel® 432 to common carp embryolarval stages in river water: Influence of physicochemical parameters in synthetic ISO water

Abstract

The lethal effects of Mexel® 432, an antifouling agent for industrial water circuits, on common carp embryolarval stages in Moselle and Seine River waters and synthetic water were tested in the laboratory. Diluting Mexel 432 in river water resulted in the disappearance of its lethal effects within a few days. In freshly prepared 3-mg/L solutions, 100% mortality occurred within 1 d in synthetic International Standards Organization (ISO) water, compared to 96 h in Seine River water (10-mg/L solutions). No lethal effect was observed after 7 d of exposure in an 8- to 15-d-old 50-mg/L solution in Moselle River water or in a 2-d-old 10-mg/L solution in Seine River water. Inhibition of Mexel 432 toxicity by river waters was not due to calcium concentration, temperature, or pH, because these factors had a negligible influence on the lethal effects of Mexel 432 in synthetic ISO water (ranges, 0.8–800 mg/L, 15–24°C, and 6.9–9.0, respectively). Aldrich Chemical humic acids immediately suppressed the lethal effects of Mexel 432 with an apparent ratio of 1 to 2 mg Mexel 432/mg humic acids. Also, clays and humic acids immediately reduced the concentration of Mexel 432 in semiquantitative colorimetric dosages.