Mercury is a naturally occurring element that is found in the air, water, and soil and exists in 3 different forms: organic, inorganic, and elemental. Pure mercury is a liquid metal and has traditionally been used to make products like thermometers. While the solid elemental form is poorly absorbed in the gut, mercury in vapor form is particularly well absorbed by the lungs. Mercury exposure at high levels can harm nerve tissue, brain, heart, kidneys, lungs, and the immune system. The three telltale signs of significant mercury poisoning are impaired speech, lack of coordination of movements, and impairment of peripheral vision.¹

Coal-burning power plants are the largest human-caused source of mercury emissions in the United States. Mercury is found in coal, and when burned, is released into the environment. This mercury eventually settles into water or onto land where it can be washed into water. Fish and shellfish are the main sources of methylmercury exposure to humans. Methylmercury is extremely well absorbed when fish or shellfish contaminated with mercury are consumed. The levels of methylmercury in fish and shellfish depend on what they eat, how long they live, and how high they are in the food chain. Generally, the larger and longer lived fish (tuna, shark, swordfish) have the highest levels of methylmercury.¹

Whole blood mercury testing is strongly preferred over serum/plasma mercury testing. Whole blood mercury testing is a good indicator of recent organic mercury (e.g. methylmercury) exposure, with 70-95% bound to hemoglobin in red blood cells with a half-life of around 50 days.²  The major excretory route for methylmercury (about 90%) is through the bile (and thus the stool), and would show on a fecal heavy metal test for mercury.

Instructions

Fasting is not required for this test. Take all medications as prescribed.

References

1. Source: https://www.medicinenet.com/mercury_poisoning/article.htm#where_you_live Accessed April 2018
2. Kershaw, TG; Clarkson, TW; Dhahir, PH. (1980) The relationship between blood levels and the dose of methylmercury in man. Arch Environ Health 35(1):28-36.