The Health Effects of Mercury

The pure element;
Inorganic compounds (such as mercuric chloride); and
Organic mercury compounds (such as phenyl mercuric propionate).

Each type poses a different health hazard.
Elemental mercury is a liquid and gives off mercury vapor at room temperature. This vapor can be inhaled into the lungs and passed into the blood stream. Elemental mercury can also pass through the skin and into the blood stream. If swallowed, however, this form of mercury is not absorbed out of the stomach, and usually passes out of the body without harm.

Inorganic mercury compounds can also be inhaled and absorbed through the lungs, and may pass through the skin. But the compounds can also be absorbed through the stomach if swallowed. Many inorganic mercury compounds are irritating or corrosive to the skin, eyes and mucus membranes as well.

Organic mercury compounds can enter the body readily through all three routes - lungs, skin and stomach.

Acute Health Effects
Very high exposures to mercury vapor in the air can cause acute poisoning. Symptoms usually begin with cough, chest tightness, trouble breathing and upset stomach. This may go on to pneumonia, which can be fatal.
If inorganic mercury compounds are swallowed, nausea, vomiting, diarrhea and severe kidney damage can occur.

Chronic Health Effects
Exposure to any form of mercury on a repeated basis, or even from a single, very high exposure can lead to the disease of chronic mercury poisoning.

There are three main symptoms:
1. Gum problems. The gums become soft and spongy, the teeth get loose, sores may develop, and there may be increased saliva.
2. Mood-swings and mental changes. People with chronic mercury poisoning often have wide mood swings, becoming irritable, frightened, depressed or excited very quickly for no apparent reason. Such people may become extremely upset at any criticism, lose all self-confidence, and become apathetic. Hallucinations, memory loss and inability to concentrate can occur.
3. Nervous system. The earliest and most frequent symptom is a fine tremor (shaking) of the hand. A tremor may also occur in the tongue and/or eyelids. Eventually this can progress to nerve tremors that make it difficult to balance or walk.

OTHER HEALTH EFFECTS
There are a number of other symptoms that may be caused by exposure to mercury and mercury-containing compounds.
- A skin allergy may develop. If this happens, repeated exposure causes rash and itching.
- Exposure to mercury vapor can cause the lens of the eye to discolor.
- Some of the inorganic mercury compounds can cause burns or severe irritation of the skin and eyes on contact.

EFFECTS ON THE REPRODUCTIVE SYSTEM
Some organic mercury compounds (methylmercury) are known to cause birth defects in children born to mothers who have been exposed to mercury.

TESTS FOR MERCURY EXPOSURE
There are two tests available to measure mercury in the body:
The Mercury Blood Test measures exposure to all three types of mercury, but because mercury remains in the bloodstream for only a few days after exposure, the test must be done soon after exposure. Most non-exposed people have mercury levels of 0 to 2 (all blood measurements are in micrograms of mercury per deciliter of blood, or ug/dl). Levels above 2.8 ug/dl are required to be reported to the Health Department. This test can be influenced by eating fish, because fish (particularly certain deep sea fish) may contain mercury.

The Urine Mercury Test only measures exposure to elemental and inorganic mercury. Organic mercury is not passed out the body in the urine and thus cannot be measured this way. A person with no exposure to mercury would probably have a urine mercury level of 0 to 20 ug/L. The Health Department requires reporting of levels above 20.