It is actually
outrageous that mercury is still used in this way. Worse are the enviro - fools who take on the
local cause in the face of the advent of modern industrial mining.
There is a solution of
course. Create an international
agreement that buys all produced mercury and sells only to users meeting modern
environmental standards. This agency
will have to buy available supplies until the mines in question do run out. Any new mines must be licensed to produce
mercury and if necessary be forced onto a quota. All this is easy enough with mercury because
it is mostly sourced from ores that specific to mercury.
This should force
artisanal miners to take their concentrate to a smelter or milling
operation. It does mean building up size
and that unfortunately allows an additional middleman. Alternatively a government mandated buyer can
operate at the mines to collect concentrates and pay on the spot. It should be done anyway to insure fair
dealing.
The artisanal miners
are not going away and they have been with us for thousands of years. Thus we need to make it safer and these two
steps can do just that. The government
can even apply a reasonable tax and collect it.
After all, the primary argument for industrial mining is that it will
pay their taxes. That is never true for
the artisan and revenue owed ends up in the pockets of the middlemen.
The
Quicksilver Demon: Rogue Gold-Mining is the World’s Largest Source of Mercury
Pollution
November
21, 2013
Mrinalini
Erkenswick Watsa,
In 1956, in the
quiet seaside town of Minamata on the southwestern coast of Japan’s Kyushu
Island, cats began to behave very strangely. They convulsed, displayed
excessive salivation, and gradually lost the ability to walk. Then, dead birds
began to fall out of the sky. Shellfish opened and decomposed. Fish also
displayed abnormal behaviors, eventually floating up to the surface of the
Shiranui Sea. Many of the ailing cats wandered into the sea and drowned. Soon,
there were no more cats alive in the area.
As if on cue,
humans then began to fall sick, reporting severe numbness of the limbs and the
inability to speak or eat. It wasn’t until 1959 that it was fully acknowledged
that a disease was responsible for these phenomena. The deaths in the cats,
birds, fish and humans were all connected. In humans we call it Minamata
disease (MD), a debilitating and chronic condition caused by consuming fish
poisoned by methylmercury (MeHg).
To date, MD has
claimed over 1,000 lives, while several thousand others have chronic symptoms.
Children have been born with congenital forms of MD, and it could contribute to
abnormally high rates of cerebral palsy.
Although an
acetaldehyde plant run by the Chisso Corporation (then called Shen Nichitsu)
was identified in 1959 as the source of the MeHg, it was not until 1968 that
the plant was closed. In 1973, Chisso was officially found guilty of
negligence. By that time, the contamination had spread across Minamata Bay,
and it took 10 years and over $487 million (48.5 billion yen) to dredge its 1.5
million cubic meters of sludge. Nets preventing contaminated marine life from
leaving the bay were in place from 1974 to 1997. Today the bay is considered
safe to fish in again.
On October 10, 2013, 57 years after that first
outbreak and 16 years after Minamata Bay was declared contamination-free, 92
countries signed the Minamata
Convention, agreeing to use mercury-free products and curtail
mercury-emissions.
“Mercury is a chemical of global concern owing
to its long-range atmospheric transport, its persistence in the environment
once anthropogenically introduced, its ability to bioaccumulate in ecosystems
and its significant negative effects on human health and the environment,”
states the Minamata Convention.
Also called quicksilver, it is liquid at room
temperature and evaporates easily. It can neither be created, nor destroyed.
Once released into the atmosphere, it retains the dubious distinction of being
able to travel thousands of kilometers, alternating between air, soil and
living organisms. It becomes concentrated as it travels up a food chain,
eventually accumulating in detrimental levels in top predators and the people
who eat them. While mercury contamination of the hydrosphere (the global water
system) may be contained via similar measures as those used for Minamata Bay,
air pollution is currently virtually impossible to control.
According to the United Nation’s Environment
Program (UNEP), “once deposited in soils and sediments, mercury changes its
chemical form, largely through metabolism by bacteria or other microbes, and
becomes methylmercury, the most dangerous form for human health and the
environment.”
Although mercury absorption from the air is
dangerous, its bioaccumulation in marine life is far more threatening because
it can lead to a large amount of mercury consumed in a single meal.
Modern Mercury
Mercury is readily encountered in an urban
environment, even in places with no connection to chemical industries. It is
used in a range of products, from electronic devices, fluorescent lamps and
batteries, to cosmetics such as mascara and skin lightening creams.
The UNEP, in its Global Mercury Assessment of
2013, reports that most of the 600,000 tons of mercury deposits in the world
today are found in a handful of countries – China, Kyrgyzstan, Mexico, Russia,
Slovenia, Spain, Ukraine and Peru. It is encouraging to note that the UNEP
also reports that the demand for mercury has dropped considerably in the last
50 years – sinking from 9,000 tons a year in the 1960s to roughly 4,000 tons in
2006 – with this trend likely to continue in the future. Unfortunately,
there are two major exceptions to this rule that together account for nearly
half the global demand for mercury. The first is the production of vinyl
chloride monomer, used to make polyvinyl chloride (or PVC), and the second is
artisanal and small-scale gold mining (ASGM).
The Minamata Convention defines ASGM as “gold
mining conducted by individual miners or small enterprises with limited capital
investment and production.” The UNEP suspects that 10-15 million people,
including three million women and children, are involved in non-industrial
scale gold mining activities across 70 countries. Artisanal gold mining
contributes 15 percent of the world’s gold production, but uses 90 percent of
its workforce. In 2011 alone, nearly 1,400 tons of mercury was used to mine
gold, which accounts for 24 percent of the global consumption of mercury. Most
of that mercury is not recycled, leaving artisanal gold mining the largest
source of mercury pollution to the environment.
Mercury and
Artisanal Gold Mining
When mercury and
gold are brought into contact with each other, even if the gold is still in a
sediment or crushed ore, they form a mixture or an “amalgam” of equal parts of
each metal. This is particularly useful when gold exists as fine particles in
river sediment, and is thus invisible to the naked eye. To retrieve the gold
from the amalgam, the mixture is subjected to high temperatures to evaporate
the mercury, leaving only the gold behind. Thus, mercury pollution can occur at
several points in this process: inappropriate storage and handling, overenthusiastic
usage and during the final evaporation step.
Mercury is a
powerful neurotoxin, and it can cause a variety of chronic symptoms and
congenital deformations particularly in developing fetuses and young children.
In its vapor form, it is rapidly absorbed into the blood stream after being
inhaled, where it damages internal organs, the central nervous system and the
immune system. Neurological symptoms in adults include tremors, memory loss and
cognitive dysfunction. In children, however, the symptoms are magnified and
include mental retardation, seizures, delayed development, language disorders
and memory loss. It has even been shown that children with higher levels of
mercury in their bloodstream are more likely to be diagnosed with attention deficit
disorder.
Due to the
significant health risks and the continually increasing financial cost of
mercury, other methods to mine gold have been proposed. Panning, which uses
gravity to separate gold from ore or sediment, can eliminate the use of mercury
completely. Mercury-use efficiency can also be increased by concentrating ore
before amalgamation, where the released mercury can be captured and recycled
with fume hoods or retorts to minimize its impact on the environment.
A video by the US EPA
that proposes a novel mercury capture system.
So why use mercury at all, particularly when
alternatives exist? A variety of social and practical factors contribute to the
appeal this chemical element has for small-scale mining operations. Its use is
quick and easy, where alternatives involve longer processing times. A single
person can independently mine gold with mercury, and it can be used in most
field conditions. It does not necessitate large infrastructural
investments, and often, its use is not a choice for a worker who is simply
following orders. In some cases, miners are unaware of the risks, and those who
are aware often cannot afford the alternatives.
A Spotlight on Peru
The Madre de Dios Department (MDD) of Peru is
home to Manu National Park, listed by UNESCO as a World Heritage Site for its
“biological diversity that exceeds any other place on earth.” The National Park
is only one of the many forested areas within the Department, which also
contains the Tambopata National Reserve, the Los Amigos Conservation Concession
and the Purús Communal Reserve.
Gasoline is carried up the Madre de Dios River
in Peru in small boats to supply the generators used to pump water from the
river onto sluice beds used for gold mining. Behind the boat you can see mounds
of sediment that has been mined for gold, a dangerous obstacle for subsequent
boat travel. Photo by Mrinalini Erkenswick Watsa
A brightly colored mining barge runs at full
capacity on the Madre de Dios River in Peru in 2010. Such barges are rare on
the river now, with most mining operations having moved further inland. Photo
by Mrinalini Erkenswick Watsa
Small-scale gold mining abounds on the banks
of the Madre de Dios River, which bisects the Department from west to east.
There have been several strikes and protests in recent years, some violent, in
response to government regulation of mining permits in the region. A lethargic
and inefficient bureaucracy and minimal supervision has resulted in a booming
mining economy that is primarily illegal. In the last five years, the Peruvian
government has aggressively combated small-scale illegal mining along the banks
of the Madre de Dios River. Unlike in 2008, when large mining barges could be
seen on the river, today’s small-scale mining has been forced to be subversive
– mining families have moved their establishments deeper into the jungle,
leaving minimal traces of their presence along the river’s edge.
Watch the four-minute trailer to Amazon Gold, a
documentary narrated by Academy Award winners Sissy Spacek and Herbie Hancock.
It reveals a “disturbing account of a clandestine journey that bears witness to
the apocalyptic destruction of the rainforest in the pursuit of illegally mined
gold.”
A recent study
by a team from Stanford University led by Greg Asner used airborne mapping and
high-resolution satellite imaging to monitor the extent of deforestation in the
Madre de Dios. They discovered that large swathes of forest have been torn down
at unprecedented rates, and that the geographic extent of mining in the area
has increased 400 percent from 1999 to 2012. Aerial imaging depicts the Madre
de Dios River as a dark chocolate brown, full of disturbed sediment and
contaminated water being carried for miles downstream. Given that nearly 200
tons of mercury is deposited annually in the Arctic from the rest of the planet
via air currents and aquatic systems, it is highly probable that the Amazon
river has received mercury released from mining along its tributary, the Madre
de Dios River.
Güido Lombardi voiceover detailing the damage
caused by gold mining in Madre de Dios in southeastern
Peru
(Spanish)
Studies also
indicate that superstitions surround the use of mercury in the Madre de Dios,
and may be affecting miners’ rates of exposure. Katy Ashe of Stanford
University reported in 2012 that some miners believe that they must stand close
to the gold to prevent its loss, which may increase mercury inhalation during
the evaporation phase of mining. Ashe also found that many miners believe that
mercury is not harmful unless it comes into contact with a wound, and is useful
as a laxative. She documented that levels of fish consumption were the
strongest predictors of levels of mercury in the residents of the Madre de
Dios, with the predominantly male mining population having far higher levels
than women in the area.
In 2013,
Stanford University’s Carnegie Amazon Mercury Ecosystem Project revealed that
60 percent of the fish species sold in Puerto Maldonado, the capital of the
MDD, contained mercury at levels higher than those specified by international
limits. A whopping 78 percent of adults in Puerto Maldonado had mercury
concentrations above international reference limits, of which women of
childbearing age (16 – 49 years) had the highest average mercury levels of any
other group.
The Future of
Artisanal Gold Mining
According to a study by Kevin H. Telmer and
Marcello M. Veiga, as reported in a volume titled Mercury Fate and Transport in
the Global Atmosphere, an estimated 640 to 1,350 metric tons of mercury
(average 1000 metric tons) is released by ASGM alone each year. Thirty-five
percent of these emissions go directly into the atmosphere, and the rest is
released into the hydrosphere.
They report that as of January 2008, the ratio
of mercury to gold prices was 1:1,650. Despite a reduction to roughly 1:567
today, these numbers still imply that mining with mercury is economically
appealing. In short, Telmer and Veiga state that mercury is “cheap, simple,
fast, independent, and reliable.”
The signatories of the Minamata Convention
have been charged with a challenging task. Despite mercury’s appeal, these
nations have agreed to take steps toward eliminating the use of mercury and
mercury compounds in mining activities within their borders. They plan to use
education, outreach and capacity-building initiatives, while providing
technical and financial assistance to miners transitioning to alternative
mining strategies.
To put this into perspective, Telmer and Veiga
predict that if the top ten countries (sans China) using mercury in ASGM were
to adopt emissions control methods such as fume hoods and retorts, and clean
mercury before use to make it more efficient at binding to gold, mercury
emissions would drop from 400 metric tons to approximately 240 metric tons per
year. The Minamata Convention can thus contribute significantly towards
reducing the global load of mercury emissions.
However, there is another layer of complexity
to this economic system. Deforestation, which can cause extensive erosion, can
also release mercury into rivers that had previously been trapped in soils. In
2010, this amounted to nearly 260 tons of extra mercury re-entering water
systems.
Sluices operate in small-scale gold mining
operations, resulting in destruction of the riverbank and deforestation for the
placement of temporary settlements. Photo by Mrinalini Erkenswick Watsa
In 2011, Jennifer Swenson and colleagues from
Duke University examined gold prices and deforestation rates in the Madre de
Dios Department. Their findings demonstrated that the price of gold is tightly
linked with increases in Peruvian imports of mercury over time, which in turns
spurs deforestation in one of the most biodiverse places on earth.
“We find that since 2003, recent mining
deforestation in Madre de Dios, Peru is increasing nonlinearly alongside a
constant annual rate of increase in international gold price (18 percent/yr),”
write the authors in the journal PLoS ONE.
Although the convention could be successful in
curbing mercury emissions in the future, it makes no mention of deforestation
as a potential contributor to the movement of mercury into water systems.
Nevertheless, it is a strong step forward and one that has been a long time
coming for children and families across the planet.
“Many of the actions to reduce mercury
emissions and releases into the environment also have multiple, green economy
benefits that can assist other international aims,” said Achim Steiner, UNEP
Executive Director, in his address to signatories from nearly a hundred
countries waiting to sign the Minamata Convention. “In other words this treaty
can contribute to wider sustainability aims including a new and universal climate
agreement by 2015 to come into effect by 2020.”
Citations:
·
Ashe, K. (2012). Elevated mercury
concentrations in humans of Madre de Dios, Peru. PloS one, 7(3), e33305.
·
Asner, G. P., Llactayo, W., Tupayachi, R.,
& Luna, E. R. (2013). Elevated rates of gold mining in the Amazon revealed
through high-resolution monitoring. Proceedings of the National Academy of
Sciences, 201318271.
·
Harada, M. (1995). Minamata disease:
methylmercury poisoning in Japan caused by environmental pollution. CRC
Critical Reviews in Toxicology, 25(1), 1-24.
·
Swenson, J. J., Carter, C. E., Domec, J. C.,
& Delgado, C. I. (2011). Gold mining in the Peruvian Amazon: global prices,
deforestation, and mercury imports. PloS one, 6(4), e18875.
·
Telmer, K. H., & Veiga, M. M. (2009).
World emissions of mercury from artisanal and small scale gold mining. In
Mercury fate and transport in the global atmosphere (pp. 131-172). Springer US.
·
UNEP, 2012. A Practical Guide: Reducing
mercury use in artisanal and small-scale gold mining.
·
UNEP, 2013. Global Mercury Assessment 2013:
Sources, Emissions, Releases and Environmental Transport. UNEP Chemicals
Branch, Geneva, Switzerland.
·
UNEP, 2013, Mercury: Acting Now! UNEP
Chemicals Branch, Geneva, Switzerland.
·
UNEP, 2013. Mercury: Time to Act. UNEP
Chemicals Branch, Geneva, Switzerland.
1 comment:
If you propose an international agency to buy up mercury, then do so. Run with it. I'll contribute 3% of my yearly income to get you started. Mercury is ALMOST as bad a pollutant as DU, right?
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