Toxicity of metals to tadpoles of the common Sunda toad, Duttaphrynus melanostictus

Abstract

Tadpoles of the common freshwater Sunda toad, Duttaphrynus melanostictus (Amphibia, Bufonidae), were exposed for a 4-day period under laboratory conditions to copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminum (Al), and manganese (Mn) at various concentrations. Mortality was assessed and median times of death (LT₅₀) and lethal concentrations (LC₅₀) were calculated. LT₅₀ and LC₅₀ increased with the decrease in mean exposure times and concentrations for all metals. LC₅₀ (96 h) for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.03, 0.3, 4.2, 1.5, 8.8, 0.4, 1.9, and 39 mg L⁻¹, respectively. Cu was the most toxic to D. melanostictus, followed by Cd, Fe, Al, Pb, Zn, Ni, and Mn (Cu > Cd > Fe > Al > Pb > Zn > Ni > Mn). Duttaphrynus melanostictus is similarly sensitive to these metals as other amphibian tadpoles.

Keywords:

• acute toxicity
• amphibian tadpoles
• frog
• mortality
• sensitivity
• soft water

Acknowledgments

This study was funded by the Ministry of Science and Technology, Malaysia (MOSTI), under e-Science fund code number 06-01-02-SF0217.