In vivo toxicity of some cyanide-containing compounds in zebrafish (Danio rerio) embryos.

This study investigated the developmental toxicity of four cyanide-containing compounds (gold cyanide, sodium cyanide, zinc cyanide, and amygdalin) in zebrafish (Danio rerio) embryos. Fertilized eggs were exposed to concentrations ranging from 1 to 600 ng/mL for 96 h, following the OECD Test Guideline 236. Acute toxicity was determined by calculating the median lethal concentrations (LC₅₀), while developmental toxicity was assessed through a semi-quantitative scoring system based on six morphological endpoints: eye, heart, circulation, yolk sac, tail, and spontaneous movement. Of the compounds tested, amygdalin proved to be the most acutely toxic (LC₅₀ = 3.2 ng/mL), followed by sodium cyanide (6.3 ng/mL), zinc cyanide (33 ng/mL), and gold cyanide (90 ng/mL). A broadly similar toxicity ranking was observed for the severity of developmental malformations. These comparative data offer valuable insights for the environmental risk assessment of cyanide compounds, especially in areas impacted by active gold mining activities.