Surface oxides may become incorporated onto the surface of a carbon nanotube (CNT) following exposure to oxidizing agents used in routine laboratory modification/purification strategies and water treatment processes. In aquatic environments, surface oxides are expected to alter not only the CNT's sorption characteristics towards organic and heavy metal contaminants but also the CNT's aquatic stability and transport properties. Oxidized CNTs may in fact act as a Trojan horse, facilitating the unwanted transport of priority contaminate species. Consequently, the effect of surface oxidation has potentially important environmental health and safety implications for carbon based nanomaterials. To investigate these issues, a suite of CNTs with different levels of surface oxidation were prepared by refluxing CNTs in HNO3 solutions of various concentrations; X-ray photoelectron spectroscopy (XPS) showed that the surface oxide concentration increased from 3% for the pristine nanomaterials to 12.5% for CNTs treated in ~16M HNO3. Studies conducted over a wide range of aquatic conditions have shown that well-defined relationships exist between the level of CNT surface oxidation and their aquatic stability; specifically, more highly oxidized CNTs remain stable over a wider range of aquatic conditions. As the level of surface oxidation increases, the sorption properties of CNTs also displayed systematic variations: adsorption of 14C labeled-naphthalene decreased linearly while divalent heavy metal contaminates like Zn2+ showed an increasing affinity towards more highly oxidized CNTs. Preliminary results will also be presented on the influence that surface oxides exert on the transport properties of CNTs.