I am trying to create a characterisation factor for carbon fibers (more specifically their potentially toxic splinters. Some attempts have been made for simillar materials, for example by Nanotoxicity and Life Cycle Assessment: First attempt towards the determination of characterization factors for carbon nanotubes - IOPscience. The toxic splinters have an approximate form of a fibril with 0.5 um diameter and 5um length, and values assumed to be simillar to the above mentioned studies approxiations of Multi Walled Carbon Nanotubes, so molecular weight of about 1.62E30, Kow 1.03E+30, Sol25 1.92E-05, Kdoc-Kpsl 2.58E+24.I am wondering how well equipped USETox is for modelling "large particles", i.e. carbon fibers? Many of the inputs required for USETox seem not to be applicatble. The molecular weight has been estimated to 10E+07, and as the particles are non solveable, its not applicable to calculate the Kow (I think? the author of the abovemntioned article set their Kow to 1E+30, so incredibly high). Do you think USEtox is relevant for my task, if the inputs are so high/low? Are there modification i can make to the sheet that can give me better results? Are there other tools you know of that I could try? I am especially interested in the indoor compartment which I find in other simillar tools (such as Simplebox).
Thanks for the work you guys are doing! :)
USEtox is generally applicable for micropollutants, that is for chemicals with small molecular weight, including organic substances and metal ions. To adapt USEtox or similar mass balance models for fibers or other polymers would require a deep adaptation of (a) various relevant environmental processes contributing to fate factors, (b) partitioning and sorption aspects relevant for bioavailability, (c) uptake mechanisms into food relevnat for human exposure, and potentially also (d) physical vs. chemical effects relevant for human and ecological effect factors. In short, USEtox is currently not applicable to be applied to fibers of complex composition and does currently not account for physical prperties like fibre shape, chemical composition, and size.