How do mercury and lead damage the nervous system and kidneys?

Mercury and lead are potent systemic poisons that cause significant damage to the nervous system and kidneys through distinct biochemical mechanisms.12

Mercury

• Kidneys: Soluble mercury salts, such as mercuric chloride, concentrate in the kidneys after absorption. They poison the blood-filtering structures, leading to a decrease or complete cessation of urine output, which causes toxic uremia and death. At the cellular level, these salts cause coagulative necrosis by precipitating intracellular proteins.13
• Nervous System: Chronic exposure to mercury vapors or salts can result in nervous system disease. Organic mercurial compounds specifically target the central nervous system, causing lesions that lead to muscle weakness, impaired cerebral function, and paralysis, as seen in Minamata disease.13

Lead

• Nervous System: Lead accumulates in the brain, causing the degeneration of nerve cells. This leads to symptoms such as convulsions, psychoses, and coma. In children, even small amounts can cause permanent damage to developing brain structures, resulting in learning disabilities and loss of function.12
• Kidneys: Lead poisoning is known to damage multiple organ systems, including the renal system, through the gradual accumulation of the metal in body tissues.2