MP8 Metals in the Environment: Dietary concerns in Aquatic Systems
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(SOF-1117-574783) Comparison between water and dietary cadmium toxicity to Ceriodaphnia dubia.

Sofyan, A^{1, 2}, Birge, WJ^{1, 3}, ¹ Departtment of Biology, University of Kentucky, Lexington, KY, U.S.A.² College of Mathematics and Natural Sciences, Lampung University, Bandar Lampung, Lampung, Indonesia³ Graduate Center for Toxicology, University of Kentucky, Lexington, KY, U.S.A.

ABSTRACT- This study was designed to compare relative importance of water and dietary cadmium on Ceriodaphnia dubia reproduction, survival, and feeding rates. Results showed that uptake from water were more rapid than from diet. Both uptakes occured significantly independent and body burdens were additive from both sources in a combined exposure. Furthermore, cadmium trophic transfer between primary producers (i.e., Pseudokirchneriella subcapitata) and primary consumers (i.e., C. dubia) were observed. Cadmium accumulation increased progressively until organisms stopped feeding. Thereafter, cadmium body burden decreased indicating that cadmium metabolism and excretion were active. However, cadmium biomagnification from algae to C. dubia was observed to be minimal. Results also showed that both water and dietary cadmium were chronically toxic for all three endpoints. For example, the LOECs were 5g/L, 0.06g/g DW, and 2g/L+0.26g/g DW for water, dietary, and combined exposures, respectively. These results suggested that the response was independent of exposure avenues, and the effects in combined exposure were additive. This study demonstrates that dietary cadmium is toxicologically relevance and should be carefully interpreted and considered as part of regulatory assessment of cadmium.

Key words: Cadmium toxicity, Ceriodaphnia dubia, Trophic transfer, Dietary exposure