What do you think would absorb the most contaminants? Something wet and gooey? I did some aloe vera a while back. There is a lab not far from my house and I get food tested there from time to time along with my water. While the tests aren't cheap, they aren't expensive either, I think it would be interesting to bring something in and see what's there. I know they can test for heavy metals, I wonder about bpas. I guess I could just describe what I'm doing and see what there recommend to test for.