Would traces of Mercury be detectable in Dinosaur bones affected by the event?
Nope. This way way before dinosaurs even existed.
What null and void said. However, there’s a suggestion in the article that the other paleontological boundaries now be examined — obviously these jokers are I.D. (Impact Denialists) — for mercury. What actually needs to be done is examining the P-T boundary found in other locations — no mercury, no dice. It’s obvious they’re looking at a local fossil record of contamination by a nearby volcano.