Effect of AL2O3 and TiO2 nanoparticles on aquatic organisms

Environmental toxicity of aqueous disperse systems of nanoparticles of binary compounds of titanium dioxides (with particle size Delta(50)=5 nm, Delta(50)=50 nm, Delta(50)=90 nm), aluminum oxide alpha-forms (Delta(50)=7 nm and Delta(50)=70 nm) and macro forms (TiO2 Delta(50)=350 nm, Al2O3 Delta(50)=4000 nm) were studied using biological testing methods. The bioassay was performed using a set of test organisms representing the major trophic levels. We found the dependence of the toxic effect concentration degree of nTiO(2) and nAl(2)O(3) on the fluorescence of the bacterial biosensor "Ekolyum", the chemotactic response of ciliates Paramecium caudatum, the growth of unicellular algae Chlorella vulgaris Beijer and mortality of entomostracans Daphnia magna Straus. We revealed the selective dependence of nTiO(2) and nAl(2)O(3) toxicity on the size, concentration and chemical nature of nanoparticles. The minimal concentration causing an organism's response on nTiO(2) and nAl(2)O(3) effect depends on the type of the test-organism and the test reaction under study. We specified L(E) Delta(50) and acute toxicity categories for all the studied nanoparticles. We determined that nTiO(2) (Delta(50)=5 nm) belong to the category "Acute toxicity 1", nTiO(2) (Delta(50)=90 nm) and nAl(2)O(3) (Delta(50)=70 nm) - to the category "Acute toxicity 2", nAl(2)O(3) (Delta(50)=7 nm) - to the category "Acute toxicity 3". No acute toxicity was registered for nTiO(2) (Delta(50)=50 nm) and macro form TiO2.