Li Dan,Bi Ran,Chen Hongxing,Mu Lei,Zhang Lina,Chen Qin,Xie Haibo,Luo Yongju,Xie Lingtian
Risk assessing newly synthesized chemicals prior to their applications is extremely important, if we want to ensure substitution of risky chemicals with more benign ones. During the past two decades, many analogs of bisphenol A (BPA) have been manufactured, while their toxicity remains less studied. The aim of this study was to compare the acute toxicity of a synthesized lignin-derived BPA (LD-BP) with that of BPA in representative aquatic organisms including two algal species ( Chlorella pyrenoidosa and Scenedesmus obliquus ), a cladoceran species ( Daphnia magna ), and the Japanese medaka ( Oryzias latipes ). The results revealed that the two algal species showed different responses to the two chemicals. For C. pyrenoidosa , both BPA and LD-BP stimulated growth within 48 h of exposure, except for the 50 mg L −1 of LD-BP treatment. After 96 and 144 h of exposures, BPA stimulated the growth of C. pyrenoidosa at low-exposure concentrations but inhibited its growth at high concentrations, while LD-BP caused a concentration-dependent response in C. pyrenoidosa . S. obliquus exhibited a monotonic concentration-response curve for both BPA and LD-BP exposures. For both D. magna and O. latipes , concentration-responses were monotonic with 96 h–LC 50 of BPA and LD-BP of 11.7 and 5.0 mg L −1 and 9.4 and 4.1 mg L −1 , respectively. Our results demonstrate that LD-BP is more toxic than BPA in the representative aquatic organisms, and it can pose higher ecological risk to the aquatic ecosystem than BPA.
Silver nanoparticles (AgNPs) released into the environment are subject to environmental transformation processes before accumulating in aquatic organisms and transferring along the food chain. Lack of understanding on how environmental transformation affects trophic transfer of AgNPs hinders accurate prediction of the environmental risks of these widely present nanomaterials . Here we discover that pristine AgNPs as well as their sulfidation products (Ag 2 S-NPs) and dissolution products (Ag + ) tend to be accumulated in Daphnia magna and subsequently transferred to zebrafish. In D . magna , Ag + exhibits the highest bioaccumulation potential whereas Ag 2 S-NPs show the lowest bioaccumulation. Surprisingly, the biomagnification factor of Ag + along the D . magna -zebrafish food chain appears to be significantly lower relative to AgNPs and Ag 2 S-NPs, likely due to the limited release of Ag from D . magna to zebrafish during digestion. Moreover, AgNPs and their transformation products mainly accumulate in the internal organs, particularly intestine, of zebrafish. Adsorption of AgNPs on the surface of the intestinal cell membrane mitigates depuration of AgNPs and, at least in part, leads to the larger biomagnification factor of AgNPs, relative to their transformation products. This research highlights the necessity of considering environmental transformation processes of nanomaterials in assessing their bioavailability and risk.
危险品化学品经营许可证（带存储）