Actually, I think the connection between cheap bagged tea and things like heavy metal poisoning/nasty pesticide use isn't really a consistent one. Simply put, a lot of the fancy loose leaf, expensive snobby elitist teas are grown in countries which aren't heavily regulated for pesticides and whatnot. If you go into some little "authentic" Chinese tea shop or something and pay a fortune for some high end oolong or something, odds are it was treated with pesticides that haven't been allowed on Californian tomatoes for decades.
I've also read some research suggesting that the organic label on teas doesn't actually mean it doesn't have harmful traces of heavy metals in the tea, leached from the ground.
So yeah, when you pay big money for loose leaf teas, you aren't necessarily paying for pesticide free, and even when you buy organic, that doesn't mean that there aren't traces of heavy metals in them which have been leeched from the soil.
"
A Tata Tea spokesperson said, “The environmental contamination through air and soil was responsible for lead contamination in tea plants, on which we have no control.”"
http://www.dnaindia.com/mumbai/repo...2-brands-of-organic-tea-made-in-india-1545512