Induction of metallothionein in dogwhelk Nucella lapillus during and afterexposure to cadmium

Induction of metallothionein (MT) was investigated in a common biomonitor, the dogwhelk Nucella lapillus (shell length: 27.7 +/- 1.4 mm; wet tissue we ight: 667+/-196 mg), during and after exposure to cadmium (Cd) under contro lled laboratory conditions (10+/-1 degrees C and 34+/-parts per thousand, s alinity). The dogwhelks were exposed to 500 mu g Cd I-1 (2.2% of 96 h LC50) for 60 days and then placed into clean seawater for 110 days. MT concentra tion in whole animal increased during the exposure period, peaked at Day 70 , and then declined gradually, Half-life of MT was ca, 40 days. MT concentr ation increased very significantly with increasing Cd concentration (r =0.7 4, n = 24, P < 0.001). Nevertheless, Cd concentration increased throughout the period of exposure and while in clean seawater, leveling off only after Day 120, indicating that Cd concentration could not be regulated by N, lap illus. Throughout the study, MT and Cd concentrations in gills, Leiblein gl and, kidney, digestive gland, and gonad tissues increased gradually. Highes t concentrations of MT and Cd were found in the Leiblein gland. Measurement of MT induction in the Leiblein gland of N, lapillus may therefore prove u seful as a sublethal biological response to Cd contamination. (C). 1999 Aca demic Press.