Exposure to relatively high levels of inorganic mercury salts can cause kidney damage. Adult exposure to relatively high levels of methylmercury through fish consumption can result in numbness or tingling in the extremities, sensory losses and loss of coordination. Exposure of the developing fetus through maternal intake of contaminated fish can result in neurologic developmental abnormalities in cognitive and motor functions. Whether any of these symptoms actually occur, and the nature and severity of the symptoms, depend on the amount of exposure. Except in occupational settings where elemental mercury is used, most of the health risk from mercury exposure is due to methylmercury exposure from fish consumption.
Many factors determine risk from exposure including the dose, the duration, and the type of contact.
The developing fetus and young children are a higher risk population because methylmercury in the mother's body may enter the unborn child and breast-feeding infants. Young children are at risk because their nervous systems are still developing and because of their lower body weight compared to adults. Exposure and health risks may be determined by measuring the amounts of mercury in blood, urine, breast milk and hair. Over time, your body can rid itself of some contamination. Adults who consume an unusually large amount of contaminated fish on a regular basis may also be at risk.