Dose-effect correlation of chloride de-icing salt on Euonymus japonicus

In order to prevent severe pollution by de-icing salt on greenery along urban roads, a half lethal dose (LD₅₀) for a plant population was confirmed through stress simulation of chloride de-icing salt on Euonymus japonicus, with an analysis of physiological changes, statistics on mortality rate on plant populations and mathematic modeling during a 30-day subacute toxicity test. The results indicate that a significant positive correlation in the early stages and a significant negative correlation in the later stages were observed between the amount of chlorophyll a and b in plants and a cumulative dose of de-icing salt. The amounts of free proline in plants and the dose of de-icing salt were positively correlated over the entire period. No significant correlation in the initial stage, but a significant negative correlation in later stages was observed between the soluble protein and the dose of de-icing salt. LD₅₀ of this chloride agent on E. japonicus is 5 kg·(L·m²)^-1 over 30 days.