Ecotoxicity of the nonsteroidal ecdysone mimic RH-5849 to Daphnia magna
The nonsteroidal ecdysone mimic 1,2-dibenzoyl-1-tert-butylhydrazine (RH-5849), a novel insect growth regulator, is mainly registered for use in rice fields. So far, its toxicity and ecological risks towards aquatic cladoceran invertebrates remain unclear. In this study, RH-5849 was evaluated for its acute and 21-day chronic toxicity towards Daphnia magna. The viability, morphology, growth, and reproduction of D. magna were observed to establish a concentration-toxicity relationship associated with the RH-5849 exposure. In addition, the relationship between the changes of physiological and biochemical indices and the chronic indices was analyzed in order to find potential early warning indicators in D. magna to the chronic risk of RH-5849 exposure. The results showed that the 48-h EC50 of acute immobilization and EC50 of 21-day survival of RH-5849 on D. magna were 45.3 and 1.34 mg/L, respectively. Chronic exposure to RH-5849 mainly affected the reproductive parameters of D. magna and the no observed effect concentration (NOEC) and the EC50 were 0.050 and 0.5423 mg/L, respectively. The number of offspring per female reduced significantly after 21-day exposure to 0.10 mg/L of RH-5849. The morphological changes, manifested in head width and body length, the length of the helmet or apical spine, and the curvature and transparency of the body, were observed in RH-5849-treated groups. Moreover, it was found that the alkaline phosphatase activity in D. magna after 5–7-day exposure was positively correlated with the number of offspring per female after 21 days. These results indicate the potential risk of RH-5849 towards aquatic crustaceans should be taken into consideration when applied to rice fields.
KeywordsRH-5849 Daphnia magna Chronic toxicity Growth Reproduction
This research was financially supported by the National Natural Science Foundation of China (Grant number 21407056).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
- Bagheri F, Talebi K, Hosseininaveh V (2010) Cellular energy allocation of pistachio green stink bug, Brachynema germari Kol. (Hemiptera.: Pentatomidae) in relation to juvenoid pyriproxyfen[J]. Afr J Biotechnol 9:5746–5753Google Scholar
- Chèvre N, Brazzale AR, Becker-van Slooten K, Behra R, Tarradellas J, Guettinger H (2005) Modeling the concentration-response function of the herbicide dinoseb on Daphnia magna (survival time, reproduction) and Pseudokirchneriella subcapitata (growth rate). Ecotoxicol Environ Saf 62:17–25CrossRefGoogle Scholar
- Du YZ, Liu AX (2002) Research advance on nonsteroid ecdysone agonist. Pesticide 4: 7–11. (In Chinese)Google Scholar
- Jiang JL, Shi Y, Shan ZJ, Yang LY, Wang XR, Shi LL (2012) Bioaccumulation, oxidative stress and HSP70 expression in Cyprinus carpio L. exposed to microcystin-LR under laboratory conditions. Comp Biochem Physiol, Part C 155:483–490Google Scholar
- MOA PRC (2014) Test guidelines on environmental safety assessment for chemical pesticides―part 13: Daphnia sp. acute immobilisation test. GB/T 31270.13–2014.Google Scholar
- OECD (1998) Test guideline no. 211. Test guidelines for testing of chemicals: Daphnia magna reproduction test. Paris: OECD Publishing.Google Scholar
- OECD (2004) Test guideline no. 202. Test guidelines for testing of chemicals: Daphnia sp. acute immobilisation test. Paris: OECD Publishing.Google Scholar
- OECD (2008) Test guideline no. 211. Effects on biotic systems test: Daphnia magna reproduction test. Paris: OECD Publishing.Google Scholar
- Rui CH, Liu J, Ren L (2012) Toxicological mechanisms and resistance of insect growth regulators. J Biosafety 21: 177–183. (In Chinese)Google Scholar
- Sumiya E, Ogino Y, Toyota K, Miyakawa H, Miyagawa S, Iguchi T (2016) Neverland regulates embryonic moltings through the regulation of ecdysteroid synthesis in the water flea Daphnia magna, and may thus act as a target for chemical disruption of molting. J Appl Toxicol 36:1476–1485CrossRefGoogle Scholar
- Xu H, Li Z (2007) Residue and degradation of RH-5849 in rice and soil. J Agro-Environ Sci 26:1759–1763Google Scholar
- Zhong Y, Zang Y, Luo Y, Kong ZM, Shen JP (1999) Toxicological study of two new pesticides on earthworms. Agro-environ Protection 3: 102–105. (In Chinese)Google Scholar
- Zhu YX, Jiang JL, Shan ZJ, Bu YQ, Xu WL, Cheng Y (2014) Acute and chronic toxicity of RH-5849 to Daphnia magna. J Agro-Environ Sci 33: 2309–2314. (In Chinese)Google Scholar