The aim of the study was to assess the effects of silver nanoparticles (AgNPs1 = 2.7 d·nm, AgNPs2 = 6.5 d·nm) and silver nitrate (AgNO3) on Enchytraeus crypticus and Folsomia candida using toxicity tests (OECD Guideline 220, 232). A 28-day chronic toxicity study was performed to evaluate the reproduction and mortality rate. E. crypticus reproduction was more sensitive to AgNO3 with a 28dEC50 of 86.40 (62.52-119.4) mg·kg-1 dry weight (d.w.) compared to AgNPs1 (28dEC50 = 119.3 (60.4-235.6) mg·kg-1 d.w). Similarly, the reproduction of F. candida was inhibited the most by AgNO3 with a 28dEC50 of 126.2 (104.2-152.9) mg·kg-1 d.w. followed by AgNPs1 (28dEC50 = 158.7 (64.05-393.2) mg·kg-1 d.w.) and AgNPs2 (28dEC50 = 206.4 (181.9-234.1) mg·kg-1 d.w.). No mortalities were observed for tested soil invertebrates exposed to AgNPs at concentrations up to 166 mg·kg-1 d.w. of AgNPs1 and 300 mg·kg-1 d.w. of AgNPs2, respectively. It was found that silver ions are more toxic in comparison with AgNPs.
Keywords: EC50; Nano silver; Silver nitrate; Springtail; Worms.