Mercury compounds settle into sediments of lakes, rivers and oceans. Fish primarily absorb methylmercury from the prey they eat. Fish also absorb methylmercury from water as it passes over their gills. Practicing rituals that include the use of mercury. Release of mercury from dental work and medical treatments.
Health problems caused by mercury are most severe for a developing fetus and for young children.
Babies whose mothers, during pregnancy, eat fish contaminated with large amounts of mercury are at greater risk for changes in their nervous systems, and possibly in their heart or blood vessels. Nervous system changes can affect their baby's ability to learn. In adults, methylmercury can lead to problems of the central nervous system and possible adverse effects on the cardiovascular system. This means that mercury has been found to produce cancer in two animal species, but that evidence is not adequate to say that it causes cancer in humans. Fish is a healthy food.