Health Consequences of Exposure to Mercury

Oct 01, 2017 AFC Column, Features / Columnists

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This is the final installment in the series on eliminating the use of Mercury in Artisanal Gold Mining operations. In local parlance, we call these miners porkknockers, though quite a few medium scale miners use mercury to amalgamate gold.
We expect that the information provided in this column (some compliments of www.epa.gov) would act as a wake-up call to our miners in the interior regions who persist in using Mercury as a binding agent to extract raw gold from ore.
Guyana is among the last few gold-producing states that have not instituted an outright ban or imposed stringent restrictions on the use of elemental mercury (miners mix it with gold-containing ore to form the amalgam which is then heated to vaporize the mercury, remove it from the gold).
We have found out that mercury released by small-scale mining around the world is a very significant source of atmospheric pollution, and it has been added to the list of “must-do’s” in the fight against global warming.
To recap, mercury released during burning of amalgams can seriously contaminate local environments including homes, neighborhoods, clothing and food. Mercury is poisonous and can be easily absorbed by humans and animals and marine life.
The chemical form of mercury in fish is different than the elemental mercury found in thermometers or used in mining. This form of mercury is called Methyl Mercury that is considerably more toxic than elemental mercury.
Because of the extreme toxicity of this compound, it is very important that mercurial waste is controlled or eliminated altogether so Guyana could return our rivers and creeks to their formerly uncontaminated state. We wish to keep our wildlife healthy, as well as the people who are not involved in mining and who rely on the rivers and fish life to live.
Risks of human exposure to mercury
For small and large-scale miners, mercury is absorbed directly through the skin during the amalgamation process. However, the main route of exposure is through inhalation of mercury vapors during the burning of amalgam.
The second most dangerous route to mercury poisoning is consumption of the fish living in contaminated rivers and creeks. Remember that in fish, elemental mercury is quickly converted to the lethal Methyl Mercury.
Both mercury vapor and methyl mercury do affect the brain, the nervous system, and all of your five senses – vision, hearing, taste, touch, and smell. It affects your internal organs – liver, kidneys, glands, etc.
Through the nose, mercury is absorbed by the lungs and it passes directly into the bloodstream where it is carried to every organ in the body. The body retains 80 percent of all inhaled mercury vapor. Note: Wearing a dust mask does not afford any protection from mercury vapor.
A very harmful intruder
Mercury has no biological purpose so the human body recognizes it as a harmful intruder. The liver and kidneys attempt to rid the body of mercury that entered through the nose or skin. The liver attempts to detoxify through the digestive system. The kidneys attempt to get rid of it in urine. These ‘interventions’ work but they don’t get rid the body of all the mercury. That takes a long time.
Urine is one of the best indicators of the presence mercury in your system, followed by its concentration in the breath. A person who recently burned amalgam, or who has been burning amalgams for some time, will show much higher concentrations of mercury in their exhaled breath.
The third measurable indicators are the blood and hair. These tend to contain methyl mercury that entered the body after consumption of contaminated fish, and exposure to mercury vapor.
Mercury becomes very concentrated in hair, about 200 to 300 times more than in blood. The hair is another means the body uses to try to rid itself of mercury. It is also much easier to measure since no special equipment or expertise is required to collect the samples. Because hair grows at an average rate of 1.3 cm per month, a record of exposure can be collected by analyzing the hair by segments. The analysis provides a history of exposure.
To eliminate this external contamination, hair should be washed with neutral detergent, acetone and water to eliminate the mercury stuck to the surface of the strands.
The concentration of Hg (metallic mercury) in hair among unexposed people is 1 to 2 ìg of Mercury per gram of hair. If a pregnant woman Í $%c s hair contains 20 ìg/g or more, there is a strong possibility that the developing fetus will be affected. Recent research considers 5 ìg/g Hg in hair as the upper-limit guideline for pregnant women if damage to the fetus is to be avoided.
Mercury is a potent neurotoxin; it impairs and destroys the brain and nervous system and other organs. The nervous system is made up of many different parts, so symptoms vary depending on the individual and on the amount of mercury and amount of time a person has been exposed.
Mercury also passes through the placenta in pregnant women, affecting the developing fetus. Fetuses and children are at greatest risk because mercury impairs proper development of nervous tissue and can cause many symptoms ranging from mild reduction in intelligence and coordination, to distortion of limbs, severe physical and mental retardation and in severe cases, death. The effects of fetal exposure to mercury may take months or even years to appear. The affected child may develop learning disabilities in later years.
Elimination of most inhaled mercury takes several weeks to a number of years. The longer a person has been exposed, especially burners, the longer it will take for the body to rid itself of mercury.
Some of the effects of exposure to mercury may be irreversible.

(www.artisanalmining.org)

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