Acute toxicity test and safety evaluation of eight aquaculture drugs in Hippocampus abdominalis juveniles

Objective The study aims to determine the safe concentrations of eight commonly used aquaculture drugs (strong chloride concentrate, formaldehyde, copper sulfate, hydrogen peroxide, zinc sulfate, metalaxyl, benzalkonium bromide, and niclosamide) for Hippocampus abdominalis, providing theoretical guidance for breeding, medication practices, and disease prevention in H. abdominalis aquaculture.

Methods Under water temperatures of 16−18℃, juveniles H. abdominalis average body length: 4−6 cm; average body mass: (1.83±0.26) g were exposed to these drugs using a semi-static water renewal and drug replenishment method. The acute toxicity and toxic accumulation characteristics were analyzed through the maximum accumulation coefficient (MAC).

Results The minimum acceptable concentrations (MAC) of 8 aquaculture drugs for juveniles H. abdominalis are all positive. Their safety concentrations, ranked from highest to lowest are as follows: formaldehyde (24.858 mg/L), hydrogen peroxide (19.498 mg/L), strong chlorine concentrate (1.481 mg/L), metalaxyl (0.369 mg/L), copper sulfate (0.339 mg/L), benzalkonium bromide (0.247 mg/L), zinc sulfate (0.185 mg/L), and niclosamide (0.024 mg/L).

Conclusion All eight drugs exhibited positive MAC values, indicating stronger cumulative toxicity than detoxification effects. Toxicity classifications were: low toxicity for strong chloride concentrate, formaldehyde, and hydrogen peroxide; moderate toxicity for copper sulfate, zinc sulfate, and metalaxyl; and high toxicity for niclosamide.