Mercury Contamination Associated with Gold Mining in Suriname

Mercury Contamination Associated with Gold Mining in Suriname and the Guianas– A Legacy to Handicap a Generation P. D. 1, 2, 3 Hays , J. V. 1 Brahana , C. J. Varnell, and S. A. Thawaba University of Arkansas, Fayetteville [1 Dept. of Geosciences, University of Arkansas, Fayetteville; 2 U. S. Geological Survey; 3 National Water Management Center, U. S. Department of Agriculture; 4 Program of Environmental Dynamics. ] SHEET 1 of 2 Dr. Van Brahana Department of Geosciences 113 Ozark Hall University of Arkansas Tel: 479 - 575 2570 / 479 - 575 3469 (fax) Webpage: http: //comp. uark. edu/~brahana Email: brahana @ uark. edu Gold Mining in Guianas reported reasons. Gold from the field still contains up to 5% or National agencies and international organizations are investing Small-scale and artisanal gold mining has become an important part cities for sale and further refining, resulting in release of mercury considerable resources in developing and improving the lives of the Guianas economy particularly for the communities (Maroons in the urban environment. No accurate data are available for the and living conditions/quality of life for peoples of the interior of and Amerindians) of the interior area as well as for Brazilian amount of mercury used in gold-mining operations or for the Guianas. These efforts include thrusts that focus on near- immigrant garimpeiros. Although total production estimates are actual amount of mercury released to the environment. At term improvements, including health care and infrastructure quite high, ranging from 10, 000 kilograms to more than 40, 000 minimum, the mass of mercury lost from gold-mining operations improvement, and long-term improvements with such long-term kilograms annually for Suriname, this production is predominantly and thus available to pollute the environment of these countries is efforts generally having a strong focus on young people, from very small operations of 1 to 10 miners, constituting a body of equal to—but likely much greater than—the amount of gold that is providing them with the intellectual tools to improve local quality people estimated to be between 15, 000 and 60, 000 involved in gold produced. Estimates for the amount of mercury released into the of life themselves through better education, preparation, and full mining in Suriname. For Guyana, official estimates indicate that French Guyana environment from 1854 to 1950 range from development of individual and community capabilities. However, small-scale miners recover more than 3, 000 kilograms per year. 200, 000 to 300, 000 kilograms. Current estimates for French a silent enemy in the form of mercury poisoning may be cutting Large-scale mining is a greater effort in Guyana, official estimates Guyana are that 5, 000 to 10, 000 kilograms of mercury are being the very legs out from under these efforts in Suriname, Guyana, indicate that miners are producing more than 8, 000 kilograms per dumped every year by gold-mining activities. For comparative French Guiana and other countries in South America. Amongst year. More than 10, 000 people are involved in mining operations in purposes, at the scale of the Amazon region, the annual import of the many problems facing the interior regions of those countries Guyana; some of this number is involved in diamond mining. French mercury for gold mining into the ecosystem is estimated to reach that need and are receiving various degrees of attention, release Guyana officially produces about 3, 000 kilograms of gold every year. of mercury from alluvial gold-mining activities to the environment Unofficially, production has been estimated to be 6, 000 to 9, 000 production estimates ranging upwards of 60, 000 kilograms and consequent mercury poisoning of local peoples is an kilograms per year. Mining is conducted by small- and medium- annually, equating to a minimum of 60, 000 kilograms of mercury unostentatious scale operations but also by artisanal miners. There about 200 released, the scale of contamination of the Guiana ecosystems De Kom et al. , 1998, tested and compared results for people complex, including air, soil, sediment, water, animals, foodstuffs, involved in mining with people not involved in mining and humans, is daunting. The significance of such contamination documented that urine mercury levels (indicative of recent exposure can be illustrated by the fact that contamination of these media is to metallic or vapor mercury forms) were significantly higher for the measurable and has significant effects in the part per million mining population (average of 27. 5 � g/g creatinine) as compared (microgram of mercury per gram of media --10 -6 g/g) and part per with the non-mining population (average of 5. 2 � g/g). Interestingly, billion (nanogram of mercury per gram of media --10 -9 g/g) range. blood mercury analyses—indicative of longer-term exposure to USEPA has established that ingesting 1. 1 µg methylmercury/kg mercury from sources including methylmercury in diet—indicated body weight/day can cause adverse effects in humans. A child both mining and non-mining populations had been exposed to with a body burden of less than 0. 002 grams of mercury can mercury. experience debilitating effects. Quik and Ouboter, 2000, found that mercury levels in predatory fish Introduction problem that may have profound ramifications. future official gold-mining sites employing about 1, 000 workers. The number of clandestine gold diggers is estimated between 10, 000 and 15, 000, spread over about 600 sites in French Guyana. Thus, in the three Guianas as much as 60, 000 kilograms of gold per year is being extracted. Most commonly, gold is mined hydraulically in the region. Hydraulic monitors, sometimes working behind an excavator, spray water under pressure to unconsolidate and mobilize alluvial and colluvial material that contains the gold. The bulk material in water suspension is pumped to a sluice box, where gravity separation is employed to partition gold from tailings. The gravity concentrate containing gold is collected for further processing, usually through mercury amalgamation. Tailings are discarded locally. Due to the alluvial nature of these gold-bearing deposits, most operations are conducted near or in stream courses, resulting in great potential for contamination of water by siltation, heavy metals and mercury. more mercury. This gold typically is transported to the capital Figure 3. Sluice box associated with gold mining. The Use of Mercury in Gold Mining and How It Is Released to the Environment While there are multiple possible sources of mercury input to the environment in the Guianas, including the mercury released from soils and vegetation during slash and burn clearing of rain forest and aerial transport and deposition from external areas, the total mass released from placer gold mining activities overshadows spread on bulk ore on the ground prior to running through the sluice box, and 3) mercury is used to amalgamate the gravity concentrate from the sluice box. Use of mercury in sluice boxes metal to the environment; fortunately, these practices do not seem to be universally applied in the Guianas. Loss of mercury to the environment through these first two methods can result in three or more times as much mercury being released to the environment as mass of recovered gold. For amalgamation of gravity concentrates, concentrates are placed in a pan or some other receiver and are mixed with mercury. Miners typically add two parts mercury to amalgamate one part gold. Excess mercury is squeezed off through a piece of fabric (this is done by hand); miners usually hope to recover about half of the mercury for reuse during the physical separation process. The gold/mercury amalgam is then heated to volatilize the mercury; thereby releasing a 1: 1 ratio of mercury to the environment for each mass Figure 2. Alluvial setting showing placer mining operations in Suriname. 0. 25 � g/g for predatory species). Additional significant findings in their study were that 57% of higher trophic-level predatory fish exhibited mercury levels in excess of the Maximum Permissible Concentration level of 0. 5 � g/g assigned by WHO. threshold for consumption of fish. 33% of the predatory fish three general modes: 1) The mercury is placed on the floor or riffles of the sluice box to contact the bulk ore, 2) the mercury is species) than in non-gold-mining background areas (average of in the Commewijne River averaged about 0. 5 � g/g, just at the safety these other inputs. Mercury is employed by different miners in and on bulk ore results in release of large amounts of the toxic Figure 1. Suriname lies between Guiana and French Guiana on the northern coast of South America. about 300, 000 kilograms. For the three Guianas, with gold Figure 4. Panning for gold Scientific Data on Mercury Contamination in the Environment Although more data are needed to characterize the distribution and degree of contamination, studies conducted to date in Suriname and Guyana provide strong evidence of environmental mercury contamination. Elevated mercury levels have been documented in every environmental compartment searched by scientific investigators—soil, sediment, wildlife, and people. Data indicate a strong relation between the occurrence of mercury and gold mining, indicating gold-processing activities are a predominant source of mercury contamination—an unsurprising, fairly common-sense conclusion given the large mass of mercury used in the industry. of produced gold. Much of this mercury can be expected to be Because mercury bioaccumulates in the food web, fish are a deposited locally as wet or dry precipitation. Retorts can be used good indicator of the presence of mercury in the environment. to recover the volatilized mercury for reuse, but these are not Mol et al. , 2001, demonstrated that mercury concentrations in consistently used in the Guianas because of cost, extra time fish species were significantly higher in areas impacted by gold required, lack of experience with retorts, noise, and other mining (average of 0. 71 � g/g for higher trophic level, predatory exceeded the WHO maximum permissible concentration. The scientists also found that mercury levels in both sediment and fish were higher in the Upper to Middle Commewijne reaches as compared with the lower Commewijne, indicating a possible identification of gold-mining activities--which are common in the upper reaches of the river--as a source of mercury contamination. David Singh et al. , 2000, conducted studies in the Kurupung and Isseneru areas of Guyana to identify the occurrence and assess the levels of mercury contamination in humans, and in the environment. The results showed that during two sampling events--February and September 2000 --12% and 14% of the population, respectively, in the Kurupung area had concentrations greater than 14 � g/g (WHO minimum known adverse effect limit on adults used in Singh’s analysis). The results from Isseneru were appalling: 96% and 89% of the population had concentrations greater than the limit for the sampling event times. These findings corroborate the fact that Isseneru is dominated by gold-mining activities while Kurupung is predominantly a diamondiferous area where gold is not extensively mined and mercury is not required for processing. The Guyana Geology and Mines Commission, 2001, performed an aquatic study in the Potaro River and found that 57% of the carnivorous fishes had elevated mercury above the WHO level (0. 5 � g/g) ; none of non-carnivorous fishes sampled had that level of contamination.

Mercury Contamination Associated with Gold Mining in Suriname and the Guianas– A Legacy to Handicap a Generation P. D. 1, 2, 3 Hays , J. V. 1 Brahana , SHEET 2 of 2 Dr. Van Brahana Department of Geosciences 113 Ozark Hall University of Arkansas Tel: 479 - 575 2570 / 479 - 575 3469 (fax) Webpage: http: //comp. uark. edu/~brahana Email: brahana @ uark. edu C. J. Varnell, and S. A. Thawaba University of Arkansas, Fayetteville [1 University of Arkansas, Fayetteville; 2 U. S. Geological Survey; 3 National Water Management Center, U. S. Department of Agriculture; 4 Program of Environmental Dynamics. ] Gray et al. , 2002, found that mine-waste sediment and mine dangerously erroneous concepts, an intelligent approach, Actions Needed Conclusion � g/l; methylmercury concentrations in mine waters ranged up to understandable by non-technical people with varying levels of The common denominator in the complex socio-environmental Gold-mining activities—though critical to the local economy— 0. 0038 � g/l. Water mercury levels generally exceeded the 0. 012 education, is necessary to move miners towards safe working problem of managing mercury contamination and minimizing may be leaving an insidious legacy with mercury poisoning � g/l EPA standard for protection against chronic adverse effects methods and communities impacted by mining activities to human exposure is the control of the use and release of crippling a broad swath of a new generation by decreasing to aquatic life. Total mercury concentrations for mine-area envisaging long term solutions to this problem. Governmental metallic mercury. Making local governmental planners, policy cognitive sediments ranged up to 0. 20 � g/l; methylmercury concentrations agencies charged with protecting health and environment in makers, and the general populace aware of environmental potentials of those individuals upon whose shoulders an in mine area sediments ranged up to 0. 0014 � g/l. Suriname currently do not recognize or at least do not assign a mercury contamination and the ultimate effect on people— improving future rests, and undercutting social efforts that offer measure of importance to the threat of mercury in diet. In particularly from encroachment of mercury on diet—should be promise. Suriname and Guyana have either low or negative Guyana, the environmental agencies are cognizant of these a first phase of activity directed at this problem. This must be population growth, thus every individual counts as their problems but very little is done in this regard. Local doctors in followed with latter phases for reducing intake of contaminated potential contribution to society is important. French Guyana Suriname are noting an increased incidence of mild to severe fish, particularly in pregnant women and young children. Also has a high population growth, due to immigration flows. birth defects—central nervous system problems, stunted limb lacking are viable, locally applicable alternative mining Mercury poisoning could not only cause failure of efforts to development, etc—that may be ascribed to mercury poisoning approaches to allow continuance of this economically improve socioeconomic conditions, but could further burden a (see study synopsis of Mohan et al. , 2003 above). There is no important industry while minimizing environmental impact. This weak economy, social services and health-care system with medical facility in Guyana for testing and diagnosis mercury additional phase of reducing and eliminating release of the care of children growing to adults with mental and physical intoxication neurological mercury to the environment can be achieved through incentive handicaps incurred by severe mercury poisoning and a general examinations and psychological tests carried out in 1997 with the and compliance (carrot and stick) programs including populace impacted with less severe effects of mercury contaminated Wayana people, evidenced minor deficiencies-- establishing and enforcing stricter environmental policies exposure but having decreased productivity and ability to especially for children--who exhibited decreased coordination of regarding mercury, strengthening of governmental institutions support social services. legs and decreased visual-spatial organization capacity; these charged with environmental oversight, and introducing and effects were linked with the ingestion of mercury. adopting The problems of mercury contamination that are damaging The state forest service in French Guyana (Office National des methodologies; e. g. improved sluice box designs, centrifugal Forêts) has developed awareness material (leaflets) which is separation technologies, and other gravity concentration distributed in the legal mining camps, to provide awareness on methods, use of retorts, centralized processing centers, etc. how to avoid the loss of mercury in the environment, how to use Greatest efficiency can be obtained if people interacting retorts, and other environmentally friendly methodologies. . . directly with gold miners are aware of the toxic effects of waters were highly elevated over local baseline concentrations. public understanding is fraught with complex, vague, and often Total mercury concentrations for mine waters ranged up to 0. 93 A study carried out in 1997 in Wayana amerindian villages of the upper Maroni river in French Guyana showed that 57% of the people had a mercury concentration in their hair above 10 µg/g (the average being 12µg/g)( Anonyme, 1999 – Programme ‘exposition au mercure de la population amérindienne Wayana de Guyane’). These high concentrations were linked to the fish consumption. A 15 to 45 years old Wayana eats about 350 gr fish per day. The levels of contamination of the fishes are so high that the quantity of mercury ingested per week (between 200 and 450 µg/g) was equal or even twice the tolerable weekly level as recommended by WHO, and even up to 10 times higher than the new references levels of USEPA. Perhaps the most worrisome study findings in Suriname to date are from a study by Mohan et al. , 2003. This group of Figure 5. Mercury is bioaccumulated in fish, in the form of methylmercury. obstetrician/gynecologists measured mercury levels in the hair and urine of mothers and newborn babies from a cross-section of ethnic groups and locations (urban and interior) in Suriname. In development of individual and community capabilities. However, a comparison with background hair mercury concentration levels silent enemy in the form of mercury poisoning may be cutting the set forth in the Journal of the American Medical Association very legs out from under these efforts in Suriname, Guyana, in humans. In French Guyana, (1999) which stated a 1. 4 � g/g background for mothers and 0. 4 French Guiana and other countries in South America. Amongst the In Brazil, a pilot awareness program was started in a village on � g/g for babies, the researchers found that 36% of the mothers many problems facing the interior regions of those countries that the Tapajos river, in the area of Santarem. Meetings were held exhibited hair mercury concentrations that were elevated and need and are receiving various degrees of attention, release of with the villagers and posters were distributed in order to invite 95% of the Surinamese babies exhibited elevated hair mercury from alluvial gold-mining activities to the environment and people to ‘eat more fishes that do not feed on other fishes’. Five concentrations. Elevated mercury concentrations were found in consequent an years after this awareness campaign, the level of mercury urban and interior mothers and babies. unostentatious future measured in the hair of these people had significantly decreased. Mean maternal hair concentration was 1. 8 � g/g, ranging up to 15. 4 � g/g; mean infant mercury poisoning problem that of local peoples may have profound is ramifications. developing fetuses are sensitive to mercury, and children of mothers exposed to mercury may show signs of toxic effects where mothers have as little as 6 � g/g hair mercury concentrations. Awareness of mercury and living conditions/quality of life for peoples of the interior of the Guianas. These efforts include thrusts that focus on near- sites through replanting and reestablishing site decreasing intelligence, decreasing Suriname, Guyana, and French Guiana are also plaguing other countries in South America. Although these other countries have similar problems, the Guianas lag behind considerably in defining, recognizing, and moving to address mercury contamination. The tools and methodologies developed for the Guianas to address the problems of awareness, education, amelioration, and reducing mercury release will have great applicability/exportability to these other countries. geomorphologic and hydrologic conditions to a more natural state is also a way to stop the release of mercury in the References environment. As mercury use begins to be controlled and release to the environment is reduced, monitoring efforts Anonyme, 1999 – Programme ‘exposition au mercure de la population amérindienne Wayana de Guyane’ (1997 -1998). A l’initiative de l’institut de veille sanitaire, de l’INSERM et du laboratoire d’écophysiologie et d’écotoxicologie des sytèmes aquatiques de Bordeaux. Rapport de synthèse IVS, Paris. Charlet L. et Boudou A. , 2002 – Cet or qui file un mauvais contamination effects on the tables. There also law projects under development to environment and people measures are taken in Suriname, Guyana or Brazil, Carmouze J. P. , Lucotte M. , Boudou A. , 2001 – Le mercure en implementation of these laws might not come to pass or the Amazonie. Rôle de l’homme et de l’environnement, risques laws might be ineffective in French Guyana due to the natural sanitaires. IRD Editions, 494 p. prohibit the use of mercury by 2006. However, if no similar Whereas most miners and people with a potential for the more transport mechanisms and far-ranging mobility of mercury and to the human societal pressures to continue using accepted and time-honored methods if a smaller subset area only toxicity, the dangers of mercury from diet and the affect on adopts environmentally friendly techniques—the mind set and children generally are not recognized nor understood in the commonly held approaches to gold mining in the Guianas. The degrees of separation between mercury source, ecoregion complex need to change as a unified whole in order environmental sinks, bioaccumulation, and ultimate human intake term improvements, including health care and infrastructure are great enough that cause and effect are far from obvious. This improvement, and long-term improvements with such long-term presents a challenge that must be met in order to protect the efforts generally having a strong focus on young people, population—to educate and bring awareness and to incite action providing them with the intellectual tools to improve local quality to ameliorate the problem. The issue of mercury and general of life themselves through better education, preparation, and full recognizing critical situations. The rehabilitation of goldmining have already started to work without mercury, using vibration mercury or mercury vapor have been made reasonably aware of considerable resources in developing and improving the lives mercury, methods to minimize emission and are capable of In French Guyana, about 8 small- to medium-scale companies direct mercury exposure pathways through exposure to metallic National agencies and international organizations are investing gold-processing and to evaluate the efficacy of efforts to improve conditions. finding strongly implicates the presence of methylmercury, which evidence from a number of medical studies shows that mercury-free the status of the environment, food supply, and public health mercury concentrations were not found to be elevated, this the source of contamination. These data are of concern in that or should continue in order to provide an ongoing assessment of hair concentration was 2. 6 � g/g, ranging up to 19. 6 � g/g. Urine is typical in persons with a diet including contaminated fish, as low-mercury abilities, to achieve effective protection of the region’s natural heritage. Figure 6. Cutting hair to measure concentrations of mercury in miners and other indigenous people. mercure. La Recherche N° 359, pp 52 -59 Krabbenhoft, D. and Rickert, D. A. , 1995, Mercury Contamination of Aquatic Ecosystems. U. S. Geological Survey Fact Sheet FS-216 -95. Le Pou d’Agouti, 2001 - Evaluation of the impacts of roads planned for the interior rainforest of French Guyana. 75 p, Le Pou d’Agouti-IUCN. Porcella, D. B. , Huckabee, J. W. , and Wheatley, B. 1995, Mercury as a global Pollutant, Water Air, and Soil Pollution, 80 (1 -4)