Species and Life-Stage Sensitivity of Chinese Rare Minnow (Gobiocypris rarus) to Chemical Exposure: A Critical Review

Chemical production and consumption in Asia are increasing at an unprecedented rate, calling for regulations on chemical management. Under the New Chemical Substance Notification in China, information on ecotoxicological effects of chemicals is mandatory for the simplified registration of chemicals with the requirement that one ecotoxicological test is conducted locally. It is now mandatory to use the native fish species Chinese rare minnow (Gobiocypris rarus). However, its chemical sensitivity compared to that of fathead minnow (Pimephales promelas) or zebrafish (Danio rerio) is still unclear. We performed a holistic literature review on toxicity data with G. rarus from 1997 to 2020. Species sensitivity among G. rarus, P. promelas, and D. rerio and life-stage sensitivity of G. rarus were systematically investigated for various chemicals using both chemical ratio distribution and probabilistic chemical toxicity distribution approaches. Comparatively, the Chinese native fish species G. rarus was more sensitive than D. rerio, particularly to metals. Juvenile and adult G. rarus were more sensitive than its larvae and embryos. The observed lower sensitivity of G. rarus embryo was likely due to the thick embryonic chorion, discrepant methods of collecting embryos, and the paucity of toxicity data, implying the necessity to standardize G. rarus embryo tests and validate the sensitivity with various types of chemicals. This unique review allows us to conclude that G. rarus studies could be used in worldwide registrations and that further investigations are needed to use G. rarus embryos as alternatives to the fish test. Environ Toxicol Chem 2021;00:1-14. (c) 2021 SETAC