The issue of heavy metals in herbs is a little bit out of context. Heavy metal pollution is wide-spread in the world. Most are in the form of air pollution, and most people get heavy metal poisoning from air. When soil is polluted, agricultural products from polluted regions may be contaminated with heavy metal.
China has areas that are polluted, therefore agricultural products from China may contain heavy metal above US standard. We use a trusted supplier that test their herbs regularly.
Furthermore, in the US, Chinese medicinal herbs are classified as food supplement, so they are subjected to heavy metal standard designed for food, which people eat in large quantity over a long time. Because the US has a stricter standard for heavy metal in food than other countries, sometime you will see imported food in the US labeled with a sticker saying, “this product my contain trace amount of heavy metal.”
But Chinese medicinal herbs are consumed very differently from food. People do not eat it nor do people consume it over a long time. It is mostly boiled into a decoction. Heavy metals are usually trapped in plant fiber and are not release by boiling. So the risk of heavy metal poisoning from drinking herbal tea is very very low. Some people who consume herbal pills or powders over a long period of time may have increased risk of heavy metal poisoning if the product is not manufactured properly. But overall the fear of getting heavy metal poisoning from herbs is based on misunderstanding.