Toxicological effect of joint cadmium selenium quantum dots and copper ion exposure on zebrafish

Quantum dots (QDs) have strong adsorption capacity; therefore, their potential toxicity to aquatic organisms from the facilitated transport of other trace toxic pollutants when they coexist has received increasing interest. However, the impact of cadmium selenium (CdSe) QDs and copper ion (Cu(2+)) joint exposure on zebrafish (Danio rerio) embryo and larvae remains almost unknown. Therefore, the present study was performed to determine the developmental toxicities to zebrafish exposed to combined pollution with CdSe QDs (500 µg/L) and Cu(2+) (0, 0.1, 1, 10, and 100 µg/L CuC1(2)) compared with single exposure. Our findings for the first time revealed that: (1) QDs facilitated the accumulation of Cu(2+) in zebrafish; (2) QDs caused higher mortality, lower hatch rate, and more malformations of the exposed zebrafish; (3) junction, bifurcation, crossing, particles, and aggregation of the exposed FLI-1 transgenic zebrafish larvae can be observed; (4) embryo cell apoptosis appeared in the head and tail region; and (5) synergistic effects played an important role during joint exposure. These observations provide a basic understanding of CdSe QDs and Cu(2+) joint toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism.