About Mercury
Blood mercury reflects recent methylmercury exposure — primarily from consuming large predatory fish (shark, swordfish, king mackerel, tilefish, and high-frequency tuna consumption). Methylmercury is a potent neurotoxin that crosses the blood-brain and placental barriers, with foetal and early childhood exposure causing the most significant developmental harm. Adults with elevated mercury may experience subtle neurological symptoms including peripheral numbness, fatigue, and memory problems; reducing high-mercury fish consumption typically normalises levels within months.