When you gain a ability score adjustment from a race, when you polymorph do you lose it since you lose abilities that are dependent on your form?
No, you keep the ability score adjustments.
Looking at the Pathfinder CRB, we can find exactly what you lose access to when you gain the new form:
Magic Chapter, Polymorph subschool rules:
While under the effects of a polymorph spell, you lose all extraordinary and supernatural abilities that depend on your original form (such as keen senses, scent, and darkvision), as well as any natural attacks and movement types possessed by your original form. You also lose any class features that depend upon form, but those that allow you to add features (such as sorcerers that can grow claws) still function. While most of these should be obvious, the GM is the final arbiter of what abilities depend on form and are lost when a new form is assumed. Your new form might restore a number of these abilities if they are possessed by the new form.
Note that ability score adjustments are either racial bonuses (for Humans, Half-elves and Half-orcs) or untyped bonuses (for everyone else afaik). They are not in any of the groups highlighted above. While the wording does allow some leeway for the DM to restrict additional abilities based on what "depends on form" the rules themselves do not suggest that ability score adjustments would be lost.
One thing to keep in mind is that polymorph spells change your form, but they do not change your creature type. You are still Humanoid(human) even while you rampage about as a lion or whatever you've polymorphed into. As a result, you should keep any racial capabilities that aren't in the "form-dependent" categories above.