Once in the bloodstream lead is distributed to three main compartments: blood, soft tissue (kidney, bone marrow, liver, and brain), and mineralized tissue (bones and teeth). Lead effects children and adults in different ways. Low lead levels in children can cause the following side effects: Nervous system and kidney damage. Learning disabilities, attention deficit disorder, and decreased intelligence. Speech, language, and behavior problems. Poor muscle coordination. Decreased muscle and bone growth. Hearing damage.