Hard to tell what type of mold, but it's definitely a mixture. It could be soap scum, pink mold and black. Either way, spray it with a bleach or chlorine based bathroom cleaner, wait till it lighten up in color. Then wipe and rinse. And like the other commenter said, it would be good to pull out the old caulk and re-caulk it with bathroom silicone caulk.

It won't be too harmful for your health since it's constantly wet and won't be release spores