how long after a mercury exposure can it be detected
1 Urine is used to test for metallic mercury and inorganic forms of mercury, but it cannot be used to determine exposure to methyl mercury. 2  Hair testing may be useful to detect methyl mercury exposures that occurred several months previously, but hair testing is relatively complex and is not used frequently.ercury testing may be ordered when a person has signs and symptoms suggesting excessive exposure to mercury. Acute signs and symptoms may include: 1  Burning in the mouth and lungs. 2  Cough, difficulty breathing, chest tightness. 3  Difficulty urinating and decreased urine output. 4  Nausea, vomiting, diarrhea, or abdominal cramping.