Marie Noele Croteau S.K. Misra D. Berhanu Samuel N. Luoma P. Christian P. O'Brien E. Valsami-Jones A.D. Dybowska 2011 <p><span>Understanding the behavior of engineered&nbsp;nanoparticles&nbsp;in the environment and within organisms is perhaps the biggest obstacle to the safe development of&nbsp;nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (</span>⁶⁷<span>Zn) ZnO nanoparticles and measured the uptake of&nbsp;</span>⁶⁷<span>Zn by&nbsp;</span><i>L. stagnalis</i><span>&nbsp;exposed to&nbsp;diatoms&nbsp;amended with the particles.&nbsp;Stable isotope technique&nbsp;is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (&lt;15&nbsp;μg&nbsp;g</span>⁻¹<span>). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000&nbsp;μg&nbsp;g</span>⁻¹<span>&nbsp;which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions.</span></p> application/pdf 10.1016/j.envpol.2010.08.032 en Elsevier Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers article