If you were born before 1990, you grew up in an environment where lead was everywhere. Leaded gasoline was sold until 1996. Lead solder in food cans was banned in the US in 1995. Residential lead paint was banned in 1978. Lead solder in plumbing was banned in 1986. Lead in ceramic glazes had no FDA limit before 1971.
Your body absorbed lead from the air you breathed, the food you ate from cans, the water from the tap, and the dishes on your kitchen table for the first 30 to 60 years of your life. About 90 to 95 percent of that absorbed lead settled into your bones, where it has been sitting and slowly releasing ever since.
For women, the release rate accelerated at menopause. For men, it accelerates as bone density loss begins around age 60 to 65. For both, it accelerates further as overall bone resorption picks up in the 70s and 80s. The lead going into your blood right now, today, is mostly the lead you absorbed in 1973.
You can't unfill the bone reservoir. But you can stop adding to it.