What are the benefits of a urine vs blood test for measuring Heavy Metals?

Most toxins are stored in fat. Weight loss and/or provocation mobilizes (e.g. releases) heavy metals from fat tissue and enters them into circulation. The Biosphere 2 project is a great example of this. According to Medline Plus, “Some heavy metals don't stay in the bloodstream very long. These metals may stay longer in urine, hair, or other body tissues.” Per this 2012 systematic review (https://www.hindawi.com/journals/jeph/2012/184745/), “sweat generally exceeded plasma or urine concentration.”