there is no such toxic level, you are safe as long as you are below 150ng/ml and you drink plently of water and no dairies int he diet.if you want to be safe you can check serum calcium level from time to time, the only danger from high levels of vit d from 100-150ng/ml up is that you absorb too uch calcium from food
I take 10k as well. I read the toxic level is 250-300k so you should be fine. Not a doctor.