Protection of Danio rerio from cadmium (Cd2+) toxicity using biological iron sulfide composites.

Cadmium (Cd2+) pollution has become a global environmental problem. This study is the first to demonstrate the feasibility and effects of applying biological iron sulfide composites (BISC) for the protection of Cd2+ exposed fish, aiming at remediation of Cd2+ polluted waters during emergency pollution events. Experimental results indicate that BISC can remove Cd2+ efficiently and significantly protect Cd2+ exposed Danio rerio, by increasing its overall survival rates. Meanwhile, the protective effect of BISC is significantly enhanced with optimized BISC dosing ratios of 2.4 or more, as well as with more rapid onset of BISC dosing following Cd2+ exposure and in water with higher pH levels in the range of 6-8, with D. rerio survival rates increased by more than 90% (P = 0.05). Additionally, BISC confers advantages over SRB and combinations of its constituents, with effective removal of Cd2+ and increasing survival rates of Cd2+ exposed D. rerio.