Clair Patterson, during a 60 year quest to prove that lead in our modern environment was harmful, went to tremendous lengths to find evidence of pre-industrial levels of lead. This is the guy who invented the clean room and associated techniques.

Were he alive today I imagine he would be glad to see this research ongoing.

Fascinating (and long) read about his journey here. http://mentalfloss.com/article/94569/clair-patterson-scienti...