Teratogenic effects of organic extracts from the Pearl River sediments on Xenopus laevis embryos

Abstract

Toxicity of organic extracts from the Pearl River sediments was investigated with Xenopus laevis embryos. The effects of sediment organic extracts on the mortality, body length and malformation of X. laevis embryos were tested by the Frog Embryo Teratogenesis Assay-Xenopus (FETAX). The 96-h LC₅₀ values for X. laevis embryos ranged from 62 to 137 g/L (g extracted sediment per L), and the toxicity effect on body length of larvae was not significant under 20 g/L. However, the teratogenic effects produced by sediment organic extracts were diverse, including edema, hypopigmentation, cardiac and ocular malformations, abdomen recurved and curved spine. The percentage of malformations increased with increasing sediment organic extracts, and even reached almost 100% at 10 and 20 g/L in Guangzhou district. A gradient of pollution in the Pearl River sediments was discerned from the teratogenic toxicity. Guangzhou district showed higher teratogenic toxicity compared with Panyu and Nansha districts as a possible consequence of high levels of PAHs, PCBs, OCPs and NP in the sediments. The teratogenic effects of organic extracts from the Pearl River sediments were successfully assessed which indicated the feasibility of teratogenic potential studies of sediments using X. laevis embryos.

Keywords: FETAX; Photobacterium phosphoreum; Sediment organic extracts; Teratogenicity; The Pearl River sediments; X. laevis embryos.