Investigations on the fish acute toxicity of fragrance ingredients, involving Chinese fish species and zebrafish embryos

Environ Toxicol Chem. 2022 Jun 23. doi: 10.1002/etc.5415. Online ahead of print.


While zebrafish (Danio rerio) has been accepted worldwide for evaluating chemical hazard to aquatic vertebrates, in some countries it is mandated to generate fish toxicity data using native species, such as Chinese rare minnow (Gobiocypris rarus) in China. This represents an additional regulatory constraint that may cause redundant tests, additional animal uses and higher costs. Previous studies showed that juvenile G. rarus was more sensitive than zebrafish juveniles and embryos to metals. To better understand the sensitivity of G. rarus to organic chemicals, we selected 29 fragrance ingredients belonging to various chemical classes and with differing physicochemical properties, for which good quality zebrafish acute toxicity data were available and tested them with juvenile G. rarus and embryo D. rerio using the OECD Test Guidelines. Chemical toxicity distribution (CTD) and chemical ratio distribution (CRD) models were established to systematically compare the sensitivity between juveniles of G. rarus and D. rerio, as well as between D. rerio embryos and juveniles. The results of CTD models showed that for tested chemicals, sensitivity of juvenile G. rarus was similar to that of D. rerio juveniles and embryos. The CRD comparisons revealed that juvenile G. rarus was slightly less sensitive by a factor of ~2 than juvenile D. rerio to ingredients belonging to Verhaar class 3 and ECOSAR ester class, while comparable to other chemicals. These comparative experiments demonstrated that fish toxicity data with G. rarus can be submitted for use in chemical registrations outside China, which would avoid repeating animal tests using D. rerio. Meanwhile, similar sensitivity of zebrafish juveniles and embryos to fragrance ingredients confirmed the suitability of replacing juveniles by zebrafish embryos. This article is protected by copyright. All rights reserved. © 2022 SETAC.

Keywords: Acute fish toxicity tests (AFT); Alternative tests; Chemical toxicity distribution (CTD); Chinese rare minnow; Fish embryo tests (FET); Zebrafish.