RP8 Ecotoxicology of Agrochemicals and Pharmaceuticals
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(KIM-1117-826873) Acute, reproduction toxicity and sublethal effects after multigeneration exposure of molinate on Moina macrocopa.

Kim, Byung Seok^{1, 2}, Park, Yeon Ki¹, Park, Kyung Hun¹, Shin, Jin Sup¹, Kim, Jin Hwa¹, Ahn, Young Joon², ¹ National Institute of Agricultural Science and Technology, Suwon, Kyunggido, Korea² Seoul National University, Seoul, Korea, Korea

ABSTRACT- Acute and reproduction toxicity tests with Molinate were conducted on Moina macrocopa. The 24 and 48h-EC50 in the acute toxicity test were 14.1 and 8.3mg/l respectively. In the 10-day reproduction test, the effect of molinate on survival, reproduction and growth of M. macrocopa were monitored at sublethal concentrations (0.25, 0.5, 1.0, 2.0, 4.0, 8.0mg/l). Total offspring and brood size, parameters used to evaluate the effects on reproduction, were significantly reduced when molinate concentration increased. The survival and growth also decreased in M. macrocopa exposed to 4mg/L and 8mg/L concentration medium. The NOEC of molinate on reproduction was 2mg/l. To evaluate sublethal effects during multigenerational exposure with molinate, F₀ M. macrocopa were exposed to the lower concentrations (0.016, 0.16, 1.6mg/l) than the NOEC of the 10-day reproduction toxicity test. The neonates (F ₁-3rd brood) from the parentals (F₀) preexposed to the herbicide were exposed to the same concentrations for 10 days. The neonates (F₂-3rd brood) produced from F₁ were exposed to the same concentrations also. The Effects on survival and reproduction of F₀ and F₁ M. macrocopa exposed to molinate were not significantly different from the control. The reproduction of F₂ M. macrocopa preexposed to 0.16, 1.6mg/l medium through 2 generations were significantly different from the control. Although M. macrocopa experienced adverse effects on reproduction when they were exposed to high concentrations of, M. macrocopa seems likely to experience no adverse effects in real environment, because the environmentally relevant concentrations of molinate in Korea are 5-28 times lower than the concentrations that showed adverse effects at present study. To investigate the development of resistance of M. macrocopa to molinate, the neonates (F₃-3rd brood) produced from F₂ preexposed to the herbicide during 3-generational periods were used in acute toxicity test. There were not any differences in their sensitivity between control groups and preexposed organisms.

Key words: molinate, Moina macrocopa, reproduction, multigenerational exposure