Titanium presence in aquatic environments comes from many sources including consumer goods and pigments such as food and other color additives. For instance, the production of TiO2 as a color additive surpasses one million tons annually, which represents an enormous source of nanoscale TiO2 entering environmental compartments, including seawater. Previous work has shown TiO2 inhibits the nitrogen cycle when introduced to cyanobacteria and inhibits calciferous coral growth of mounding coral species. In order to study the effects of TiO2 nanoparticles on Favites Pentagona Coral environment, TiO2 nanoparticles were introduced to a coral specimen in seawater tanks. The water in TiO2-exposed coral showed a nitrate spike and the coral suffered a considerable decline in health. Moreover, there was also an evident change in the algal growth pattern when exposed to titanium dioxide. In this work, we present the development of a water chemistry analytical procedure in which the absorbance of a diazotization reaction product, was measured at 390 nm by UV-Vis spectrophotometry. The method of standard additions and least squares were used to produced a calibration curve with an R2 = 0.9558. Preliminary results, show nitrite concentrations of up to 10 ppm after 96 hours of exposure. Additionally, qualitative determination of titanium speces in Favites Pentagona Coral tissues was achieved by scanning electron microscopy. A protocol for fixing live coral for SEM examination has been developed and tested with good results. Both the nitrate/nitrite quantification in seawater using UV/vis and titanium determination using scanning electron microscopy will be applicable to many sub-disciplines in the marine science and marine chemistry fields.

Development of a nitrate/nitrite determination in salt water using an azo dye method to study the effects of titanium dioxide nanoparticles in the nitrogen cycle of Favites Pentagona Coral environment

255th National Meeting (2018)

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