  Recently, a nitrogen iceberg was proposed as a possible origin for the first
interstellar object, 1I/2017 U1, also known as `Oumuamua. Here, we show that
the mass budget in exo-Pluto planets necessary to explain the detection of
`Oumuamua as a nitrogen iceberg chipped off from a planetary surface requires a
mass of heavy elements exceeding the total quantity locked in stars with 95\%
confidence, making the scenario untenable because only a small fraction of the
mass in stars ends in exo-Plutos.
