Evaluation of the toxicity of biogenic polyamines and synthetic polyethyleneimines toward aquatic animals during development from diploblastic and triploblastic lineages

抄録

Amine-based compounds, such as synthetic polyethyleneimines (PEIs) and biogenic polyamines, are promising CO₂ capture materials because of their high affinity for acidic gases. However, their potential toxicity in aquatic environments remains a concern. In this study, we compared the toxicity of three polyamines (putrescine, spermidine, and spermine) and of PEIs with average molecular masses ranging from 300 to 100,000 at concentrations of 1–1,000 ppm. Toxicity assays were conducted using planula larvae of a diploblastic species, the stony coral Acropora digitifera, and juvenile triploblasts, including zebrafish (Danio rerio), the Japanese big-eared Radix freshwater snail (Radix auricularia japonica), and embryos of the collector urchin (Tripneustes gratilla). Coral larvae exhibited high sensitivity to biogenic polyamines with a median lethal concentration (LC₅₀) of 22.2 ppm for putrescine, but relatively low sensitivity to PEIs (LC₅₀: 227.6–>1,000 ppm). In contrast, triploblastic animals were highly sensitive to PEIs (LC₅₀: 0.3–3.2 ppm), while being less sensitive to biogenic polyamines (LC₅₀: 294.9–389.7 ppm for putrescine) except for spermine. Notably, some PEIs exhibit toxicity even at concentrations below 1 ppm. These findings emphasize the importance of conducting organism-specific environmental toxicity risk assessments when amine-based CO₂ capture materials are used, particularly to avoid adverse effects on aquatic ecosystems.