Acute toxicity of boron, titanium dioxide, and aluminum nanoparticles to Daphnia magna and Vibrio fischeri

The acute toxicity of four different nanosized particulate materials (titanium dioxide, boron nanoparticles, and two types of aluminum nanoparticles (ALEX and L-ALEX)) were evaluated using two tests: the Microtox toxicity test and the acute toxicity test with Daphnia magna. The results were analyzed in order to calculate LD(50) at 24 and 48 h. It was found that titanium dioxide nanoparticles show a low level of toxicity, and LD(50) values cannot be calculated. Conversely, boron nanoparticles with EC(50) ranging from 56 to 66 mg L(-1), depending upon the age of the solution, can be classified as "harmful" to aquatic microorganisms (EC(50) in the range 10-100 mg L(-1)). We have also discussed possible mechanisms of nanoparticle toxicity and potential problems in ecotoxicological testing of nanomaterials. The studied nanomaterials can be ranked in the following order according to their Daphnia acute toxicity: boron nanoparticles>ALEX>L-ALEX> TiO(2).