I’ll still take the ones growing in dirt. The most commonly found pesticides are fungicides (I would think you would need these in hydroponocs, fungus loves water) and insecticides (again, inside and around water insects and mites are going to do really well). It’s all about what sites they tested and who is running it. Some land probably has heavy metals more. Some greenhouses will have more pesticides and plastic. I’m not sure I trust this to be completely objective and conclusive. Still interesting.