Friday, February 17, 2017
Exhibit Hall (Hynes Convention Center)
Christine Schremp, Bishop Feehan, Attleboro, MA
The purpose of this research was to determine the effects of titanium dioxide (TiO2) on the overall health of aquatic organisms, and to compare the ecotoxicity of various particle sizes. TiO2 is a common additive in consumer goods due to its applications as a pigment and a UV blocker. Other applications, especially for nano-TiO2, are constantly being explored and implemented. However, an insufficient understanding of the compound’s effects on aquatic ecosystems could lead to widespread effects due to its ecotoxicity. As there is no specific treatment targeted at the removal of TiO2 from wastewater, entry into the environment is inevitable. Due to its position in the lower trophic level of the food chain, the aquatic organism Daphnia magna was used as a bioassay. It was hypothesized that if organisms were exposed to different particle sizes of TiO2, they would show a deterioration in health, most significantly in those organisms exposed to the nanoparticles (18 nm), followed by standard (300 nm) and then food grade (1200 nm) at concentrations of 50 mg/L, 10 mg/L, and 1 mg/L. The mortality rates of organisms were compared, as well as their growth, maturation, and reproduction. The results supported the hypothesis; organisms exposed to nano-TiO2 had the highest mortality rate as well as delayed maturation and reproduction. In all of the cultures exposed to TiO2, the Daphnia exhibited increased molting due to the adherence of the particles to the exoskeleton. In addition, the particles appeared to bioaccumulate in the gastrointestinal tracts of the organisms. Overall, the ecotoxicological effects of TiO2 observed in Daphnia magna may have large implications for aquatic ecosystems.