Preserving health & the environment by eliminating Mercury in Gold Mining

Sep 24, 2017 AFC Column

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Mercury is a naturally occurring element that is present in low concentrations in all living things. Elemental mercury is a heavy, silvery liquid that has had many industrial purposes. It is used in thermometers, switches, fluorescent lights, and the manufacture of caustic soda, but it is very injurious to human health. Humans have known how to use mercury to amalgamate gold for at least 2,000 years. Mercury is the only metal that is present as a liquid at room temperature. It also has the lowest boiling point of all metals which is why it evaporates or ‘burns’ easily. Mercury vapour is colourless, has no odor, and is extremely toxic. Mercury is also very ‘sticky’. When evaporated, particles of mercury easily stick to surrounding furniture, walls, skin and clothing. Clothing worn during burning can continue to emit high concentrations of mercury for many hours and can contaminate other areas, including the air your family may breathe.

Environmental
Effects of Mercury

How does Mercury contaminate the environment? When gold miners use mercury to amalgamate gold they should be aware that they can easily contaminate themselves, their families and neighbours, even the people living in proximity with their worksites. These people are generally the indigenous who depend on that environment to eat, earn and live. When miners do not consider the effects of their activities on the environments they work in, they could unconsciously contaminate those environments and other people living and working in it, e.g. if a mining operation does not have a ‘settling pond’, or if waste matter containing mercury is casually dumped from the dredge or boat into the river. In either case, mercury would be carried downstream and dispersed over a very wide area. It is then transformed into methyl mercury and settles at the bottom of the river, creek, trench, stream and every other natural water source nearby. Methyl mercury is easily absorbed by worms (bait for fishing), snails and insects, but the real danger is in the fishes that absorb mercury. In those fishes, mercury becomes highly concentrated. People living in interior regions, eat fish as a dietary staple. Miners eat a lot of fish. Some animals eat fish.
When people in the vicinity and farther downstream of a gold mining camp that uses mercury, drink and wash in the same river, they are unknowingly ingesting the metal and they become ill. The health risks are enormous and deadly. They affect unborn foetuses, children, toddlers and adults. (Read “Babies at Micobie born with deformities”, Guyana Chronicle 09/18).
Likewise, mercury vapour emitted from open-pan amalgam burning disperses into the air. Most of the vapour settles on the ground so the soil becomes contaminated; sometimes as far as 2K downwind from the burning. Vapour is also known to travel long distances, and to stay suspended in the air. When rain falls, it comes down with raindrops.
Here is an interesting fact: Even abandoned mining sites could continue to emit mercury into the atmosphere and water for many years after mining has ceased. The mercury that is released during amalgamation in or near to rivers immediately contaminates the soil, the water and the air that is breathed by miners and residents nearby and along the way for miles. In addition, microscopic droplets of mercury attach themselves to fine sand and muddy river sediments which travel easily downstream, ending up far away from mining areas. Even with the best care, even if amalgamation is conducted in enclosed ponds, elemental mercury still sticks to small particles and they disperse widely, especially during rainy seasons.
Remedying and avoiding mercury contamination There are a few remedies and avoidance strategies that could prevent people from becoming ill in, or near to, or downstream of a gold mining operation that utilises mercury. The most certain prevention method is for us to gain the cooperation of miners and mining companies to STOP USING MERCURY! Here are some examples:-
· Environmental ‘cleansing’ of abandoned sites which only resolves part of the problem
· People should not eat fish, meat and other foods that were caught or picked in or near to gold amalgamation ponds, contaminated rivers or creeks
· Amalgamation with mercury should only be carried out in ponds that were dug specifically for this purpose. These ponds must be properly lined preferably with cement
· Fish for consumption should only be grown in special ponds that are protected from creek or river water that flows past/through a mining camp. The fish ponds should be dug in ‘safe’ places located some distance away from a contaminated creek or river. This is to prevent overflow during heavy rains from leeching into the waterways
· Water that has been contaminated with mercury, or has been used for amalgamation, must NEVER be used for cooking, bathing or drinking
· It is important that forests around mining areas are protected and are not cut down. They act as “buffer zones” by allowing sediments to settle close to the point of origin (POO) of contamination. Trees could prevent the movement of mercury from the POO downstream to where it can be transformed into harmful methyl mercury.
· Residual mercury in creeks and rivers must not be allowed to reach open aquatic systems
(Next: Health Consequences of Mercury Exposure)

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