After vaius comparison: The simapro with the ecoinvent 3.4 reports same values
the simapro with the ecoinvent 3.3 reports more allined results (the relative values between arsein toxixity in water is higher in respect to the air)
This characterization factor is in CML-AI > Human toxicity.
also, in the case of CML-IA the Arsenic in air present characterization factors much higher then mercury in air. I don't know if this is due to the different unit (1,4DB eq vs CTU) but the CML factor are higher also in respect to the RECIPE which use the 1,4DB eq.