Thoughts on smelly sink + plumbing?

About a month + a half ago, I started to smell this vile smell - like grease trap on steroids - while running the water in one prep sink. Fast forward to now, I can smell it about 5 ft away, w/ my back turned away from the sink, and I can’t prep at the salad station near it for more than 5 minutes w/o getting a headache, nausea, or both. For shits and giggles, I poured bleach + liquid drano down the drain to see if it would help at all, but it didn’t. I’m pretty certain it’s related to the exposed pipe underneath. RE: photos attached. I’m no plumber, but this just doesn’t seem right at all. I spoke to my boss about the smell, and she doesn’t care bc she doesn’t smell it. When I first spoke up about the smell, no other staff member smelled it, but in the past 2 weeks, 2 of my coworkers have started to catch whiffs of it. I was hoping my boss would care once her son smelled it, but nope. I don’t want to work like this anymore bc it’s really bothersome, and I do genuinely worry about the cleanliness of the cafe and the entire staff’s health (if it’s toxic). I know I can’t keep nagging bc I’m not being heard. What do I do? Are my concerns valid?