If you can, record and document. After you do that, go back to HR (or whoever you talked to the first time) and play the recording and show your documentation. If they still won't do anything file a complaint with the EEOC. Another alternative is to go to the media with all your evidence, however that could bite you in the ass.

I would also keep looking for another job.

So when you went to the supervisor he said you're gunnysacking, but then said he can't do anything? So why would he think you would go to him again? Did you bring one issue to him or numerous? What racist thing actually happened that you claimed?

I can’t say what you should do but what I would do in that situation is stay cool, start looking for another job, not necessarily with the intention of taking it but as a backup so you can negotiate from a position of power, or to fall back on if things go south. Then I would try to make a friend, to have an ally there, and then make another. Meanwhile I’d take it all as a challenge, do the best I could do with the bad situation, and not worry about the outcome because I had made every reasonable effort to cover all my bases while being fair and humane to all others concerned.
If another job comes through that actually looks more appealing... I’d be gone! If things start to turn around before a better job shows up... I’d feel triumphant, but I’d prolly still keep an eye on the job market; that really sounds like a permanently stressful environment.

Being Hispanic... I can say I had received more racism from blacks than of whites despite my non white skin color. I had to live outside of usa to learn that races are not colored!!! You have to be True to Yourself. To think that a "minority" in this country will not use numbers to his/her advantage when available is pretty Naive. Go with your Conscience. Keep a ledger, document everything. I know is a Tough Spot for you because the "minority" in your workplace rather have another "minority" in your place. Like sharks... if they smell blood in the water... they will feel empowered!!! Give the grades they deserve. Found another place to work... this is about You and should be about You. Nobody else is going to look out for you and america in all different manifestations, still sucks. Find a better place to work. And wishing you the Best of Lucks.

As others have advised.. the most likely path to being happier will likely require you to find a different job. In the mean time, don't give up, with time a different path will likely open itself up to you.. it could even be as something as simple as you need to be there a certain length of time before your accepted.

I don't know what to tell you, people will try to help you but everyone has a different opinion and do things differently. While you're working there keep your journal going, write down everything. One thing for sure is to try to find a better workplace. I believe you will make the decision when the time comes for the best or for the worst. I'll be here and support you, specially after passing through a similar situation, not as heavy as yours though. All the best, don't give in, never surrender.

you have fallen in with a bad crowd. you didn't go looking for it and you had no way of knowing. Unfortunately the only person you can change is yourself. The other people, no... So it looks like you will have to get another job.

Don't quit your job..... yet.
But immediately, like YESTERDAY! start searching for your new job. You're in a lose/lose situation. There is no positive outcome path there for you.

@ForeignNata -- Natalie, one of our obligations to the self is to be aware of our surroundings and circumstances so that we can avoid overloading ourselves with stress. Stress is not good for us and it is also not good for those with whom we interact. This sounds like one of those situations wherein there is no real solution. That is, it appears to me that you might find some workaround, but be left with a constant source of stress with no way to alleviate it. I hope I'm wrong, but I would resign myself to being prepared to leave if it happens to be a no-win situation. You owe it to yourself.