Which preposition to use with traffickers

in Occurrences 12%

Some trafficker in happiness, some worthless abuser of the gifts of fortune.

on Occurrences 1%

Commerce, however necessary, however lucrative, as it depraves the manners, corrupts the language; they that have frequent intercourse with strangers, to whom they endeavour to accommodate themselves, must in time learn a mingled dialect, like the jargon which serves the traffickers on the Mediterranean and Indian coasts.

Which preposition to use with  traffickers