Toxicity of exogenous antimony to the soil-dwelling springtail Folsomia candida

Antimony (Sb) is a toxic pollutant, but data for Sb toxicity to springtails in soil are limited, and the effects of Sb speciation, soil physiochemical properties, and aging time on Sb toxicity have not been investigated. To address this, the effects of Sb on Folsomia candida were evaluated in laboratory studies. The results demonstrated that compared with Sb(III), no significant change in mortality was observed in Sb(V)-treated soil, but the EC50 value for the reproduction was 28-fold higher than that of Sb(III). Sb(III) toxicity was very different in four soils. The LC50 values for the survival were 2325–5107 mg kg−1 in the acute test and 605–2682 mg kg−1 in the chronic test, and the EC50 values for the reproduction were 293–2317 mg kg−1. The toxicity discrepancies were associated with the variations in oxidation potential and sorption capacity among corresponding soils. Toxicity significantly positively correlated with the clay and amorphous iron content but significantly negatively correlated with pH. Long-term aging markedly decreased Sb(III) toxicity, and the EC50 and LC50 values were unexpectedly higher than the highest test concentration in soil aged for 180 days. Sb(III) toxicity was probably modified more by oxidation than by changes in the available Sb fraction during aging.