Quantification of titanium dioxide nanoparticles in environmental matricies

A consistent analytical method incorporating sulfuric acid (H₂SO₄) digestion and ICP-MS quantification for titanium dioxide (TiO₂) was validated for 4 environmentally relevant matrices. The method provided Ti recoveries of 97 ± 2.5%, 91 ± 4.0%, 94 ± 1.8%, and 73 ± 2.6% (mean ± standard deviation) from water, fish tissue, periphyton, and sediment, respectively. Lower recoveries from sediment coincided with the percentage of sand in the sediments used for validation suggesting that unrecoverable Ti may be sequestered in the sand matrix. Our method was then used to quantify Ti in the the four validated matrices along four reaches in the North Bosque River Watershed. Ti concentrations ranged from 0 to 8 μg L^-1 in water, 45 to 526 μg g^-1 in sediment, 276 to 1520 μg g^-1 in periphyton, and 0 to 30 μg g^-1 in fish tissue. Ti concentrations in periphyton were significantly higher (p ˂0.001) than concentrations in other sample types, but were independent of distance from the effluent discharge.