Carbon nanotubes (CNTs) have been widely used materials in both industry as well as in scientific research. These materials have special structures and functions. As a consequence of their pervasive use, their potential adverse effect on the environment is of concern to environmental scientist. For instance, CNTs may enhance the toxicity of polycyclic aromatic hydrocarbons (PAHs) after release to the environment due the fact that they are superior sorbents. In environmental water system, natural colloids widely exist. The interaction between natural colloids and CNTs may change CNTs' adsorption capacity of PAHs. This research investigates adsorption capacity of two different CNTs of PAHs namely, napththalene, phenanthrene and pyrene in water and in the presence of colloids. Adsorption capacity of two multi-walled CNTs was examined in the presence of pure water, 0.5 ppm and 20 ppm of selected PAHs. This is then followed by a study of the interaction between these two CNTs and natural colloids filtered from lake water. The adsorption of PAHs to CNTs equilibrated with colloids will also be determined. Gas chromatography mass spectrometry (GC-MS) was employed to quantify samples. Adsorption isotherms are then fit over the concentration ranges and PAHs analyzed. Results obtained from this planned study will enable the evaluation of the potential environmental impact of CNTs as sorbent materials. Also the nature of the interaction of the colloids with CNTs will be useful in determining their environmental applications. The present work is ongoing. We hope to generate enough data in a few months.