Arsenic is a naturally occurring element in the earth's crust and is found throughout the environment, but compared with other toxic elements, little toxicological work has been conducted on arsenic. In this study, we tested the effect of two different arsenic compounds (arsenite (NaAsO2) and arsenate (Na2HAsO4)) on the reproduction of soil inhabiting collembolan species (Paronychiurus kimi). The toxicity tests for each arsenic compound were conducted in accordance with the ISO 11267. The estimated EC50s for reproduction of each arsenic compound were 20.43 (16.97-24.60) and 32.86 (25.64-42.13) mg/kg, respectively. There were statistically differences in the toxicity of two different arsenic compounds based on overlapping 95 % confidence intervals. The relative toxicity ratio of arsenite to arsenate (approx. 0.62) as well as the concentration-dependent decrease in reproduction of P. kimi was steeper at arsenite than that of arsenate. These results show that arsenite was more toxic to P. kimi than arsenate.

• Jino Son(Department of Environmental Science and Ecological Engineering, Korea University)
• Kijong Cho(Department of Environmental Science and Ecological Engineering, Korea University)