It is important to note that ASGM is not the only factor to consider when assessing mercury contamination. 8 Estimates of mercury emissions in the Peruvian Amazon have been particularly alarming, with 185 tons released in riverways per year. While there is a lot of uncertainty when it comes to estimating mercury pollution, one study estimated that ASGM accounts for 71% of total emission in the Amazon. 7ĪSGM is widespread in the Amazon and accounts for a significant source of mercury pollution. One study in the Amazon and Orinoco Rivers found that 26% of river dolphins exceeded safe limits for humans set by the WHO. 6 Fish-consuming animals like river dolphins and jaguars are also at risk. In Madre de Dios in the Peruvian Amazon, authorities declared a state of emergency in eleven districts in 2016 due to mercury poisoning in local populations. 5 People are exposed in a variety of ways, but fish consumption is a dominant pathway. Elevated mercury levels in humans are widespread in the Amazon region, particularly in indigenous communities, which report on average 7.5 times higher than background levels in the general population. Mercury contamination and exposure endangers the health of the people, plants and animals of the Amazon. When disposed of improperly, this process releases mercury-cyanide complexes into waterways, which are highly bioavailable and represent a significant threat to downstream aquatic life. Some miners and mineral processors may also use sodium cyanide to obtain residual gold from mercury-contaminated tailings (mining waste). Furthermore, when miners and owners of gold shops burn the mercury-gold amalgam to purify the gold, their families and communities may directly inhale dangerous amounts of mercury vapor. Once in waterways, bacteria absorb mercury and transform it into methylmercury, an organic compound more toxic than inorganic mercury, which bioaccumulates up the food chain. When miners mix the gold-bearing ore with mercury to extract gold, mercury enters the local environment, where it can precipitate into ecosystems, poisoning rivers, fish and crops. While relatively uncommon in the Amazon, whole-ore amalgamation is considered by the Minamata Convention on Mercury as a worst practice, to be eliminated. There are two ways of using mercury in gold mining: concentrate amalgamation, in which miners apply lesser quantities of mercury after concentrating the ore and whole-ore amalgamation, in which miners apply greater quantities of mercury without prior concentration. 3 Miners typically use mercury to separate the gold, forming a mercury-gold amalgam. Mercury and Artisanal and Small-Scale Gold MiningĪrtisanal and small-scale gold mining (ASGM) is the largest human-caused source of mercury in the environment, emitting as much as 1,000 tons of mercury, roughly 40% of the global total. Mercury exposure can lead to behavioral changes that debilitate an animal’s capacity to mate, hunt, and avoid predation, compromising the survival of affected populations and overall biodiversity. Experts have found evidence that mercury contamination affects populations of wildlife impacting reproduction, growth, neurodevelopment, and learning ability. The toxicological effects of mercury are not only dangerous to humans. According to the WHO, mercury is one of the top ten most dangerous chemicals to public health. Exposure is particularly dangerous for children in utero and in early development. Exposure to mercury affects the brain, nervous system, kidneys, and lungs and can include symptoms such as lower IQ, sensory impairment, susceptibility to disease, disturbed sensation, and a lack of coordination. When not handled properly, it can have extremely damaging – even fatal – effects on humans, animals, and the environment. The only metal that remains liquid at room temperature, mercury is difficult to contain and, once released, can travel long distances through water, air and the food chain. Mercury is a naturally occurring element found in air, water, and soil.
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