# Isoptope effect on electrophilic aromatic substitution

I am not able to figure out how. All EAS reactions proceed by formation of an arenium ion and then the loss of an $$H^+$$ ion to regain aromaticity so all of them should be equally effected ( textbook does not mention how they are effected). I feel the only effect should be due to difference in bond enthalpies of $$C-D$$ bond and $$C-H$$ bond.
I came across this reaction mechanism from chemlibretexts: The hydrogen released is taken up by the $$-SO_3H^-$$