Grandson is putting toys tainted with lead paint in bathtub to play is this dangerous, the lead I mean?

As detailed in the other posts, take them away from the kids. I'm sure Junior has plenty of other playthings. Although the lead content is really quite minimal, why take the chance?!? I would also advise you to NOT toss tainted toys as they'll end up in a landfill. You can contact your local municipality, describe your situation and they will advise you how best to dispose of known contaminated articles.