  We investigate non-thermal electron and nuclei energy losses within the
binary neutron star merger remnant produced by the event GW170817. The lack of
a cooling feature within the detected synchrotron emission from the source is
used to constrain the magnetic field at the mG level, assuming that this
emission is electron synchrotron in origin, and that the accelerated spectrum
in the electrons follows the form $dN/dE_e \propto E_e^{-2}$. The level of
subsequent gamma-ray emission from the source is demonstrated to provide a
further constraint on the source magnetic field strength. We also put forward
alternative strong ($\sim$G) magnetic field scenarios able to support this
emission. For such stronger fields, the photo-disintegration of non-thermal
nuclei within the source is considered, and a bottleneck period of $\sim$5-30
days is found when this process peaks. We find that this class of source is in
principle able to support the population of cosmic rays detected at Earth below
the "ankle".
