The Extent of Arsenic and of Metal Uptake by Aboveground Tissues of Pteris vittata and Cyperus involucratus Growing in Copper- and Cobalt-Rich Tailings of the Zambian Copperbelt.

The Zambian Copperbelt is host to one of the world’s greatest copper and copper ore reserves and as a result, the Copperbelt is home to multiple large commercial mining operations. Many of these mining companies construct ponds called tailings ponds in which they dump the residue of the ore extraction process. Many of the metals and contaminants present in the ponds are toxic to most plants, however various plants have been identified as metallophytes and have the ability to thrive in toxic environs. Kříbek et al. determined the amount of arsenic, copper, cobalt and other metals in a Zambian tailings pond that Pteris vittata, or the Chinese brake fern— a well-known and studied metallophyte—could accumulate in its fronds (the leaves of a fern). The researchers compared the accumulation amounts of the Chinese fern to those of Cyperus involucratus, or the umbrella plant, in two distinct tailings: reddish-brown tailings with high amounts of arsenic, iron, and other metals, and grey-green tailings with a lower metallic and contaminant content. The authors found that the Chinese brake fern is a hyperaccumulator of arsenic and has adapted to high concentrations of copper, cobalt, and other metals present in Zambian tailings ponds. This conclusion points to the use of Chinese brake fern and other similar plants as tools for the remediation of contaminated soils and water in mining districts.—Monkgogi Otlhogile
Kříbek B., Mihaljevič M., Sracek O., Knésl I., Ettler V., Nyambe I., 2011. The extent of arsenic and of metal uptake by aboveground tissues of Pteris vittata and Cyperus involucratus growing in copper- and cobalt-rich tailings of the Zambian Copperbelt. Archives of Environmental Contamination and Toxicology 61, 228–242.

Kříbek et al. chose an old tailings pond located in Chambishi-North, Zambia and divided it into four vegetation zones: reed swamp, no vegetation, papyrus and fern, and semi deciduous tree forest zones. The researchers located four 1 m² sampling sites in the papyrus and fern zones and took numerous groundwater, tailings, and plant samples.  The groundwater’s alkalinity, cations, and anions were determined by titration, coupled plasma-mass spectrometry, and liquid chromatography, respectively. To determine the total metal concentration in the tailing samples, the samples were digested with aqua regia—a corrosive mixture of acids—in an attempt to dissolve all of the metals in the samples. To determine the plant-available metals, the authors used two methods: DTPA and TEA extraction and sequential extraction. These methods both leach metals and contaminants out of soil, sediments, and sludge to mimic environmental process, such as the growth of a plant in contaminated soils. In addition to establishing the pH value of the tailings’ leachates, the authors used ELTRA CS 500 instruments to determine total carbon, carbonate carbon, organic carbon, and total sulphur present in the tailings samples. The plant samples were separated into shoot and roots and were oven-dried. The dried samples were then burned down in a muffle-oven and the remaining ashes were analysed for metals using hydrochloric acid and nitric acid. Iron and aluminium accumulation by plant roots were studied using an optical microscope and electron microprobe. Finally, the authors calculated bioaccumulation factors (BF) for each contaminate for each plant and tailings type. The BF is a measure of the ability of a plant to intake and transport metals to the rest of the plant tissues.
The groundwater samples showed that the dominant cation was calcium while sulphur was the dominant anion. The concentration of magnesium, copper, manganese, cobalt, and potassium were also significantly high. The other contaminants found in the tailings samples such as aluminium, iron, zinc, and arsenic were significantly lower in the groundwater. The groundwater concentrations were used in conjunction with the plant concentration to obtain an accumulation ratio which the authors used to evaluate the amount of contaminates the plants were accumulating from the pond water. The accumulation ratio of arsenic in both the umbrella plant and the Chinese brake fern was the highest of any of the contaminants. In the Chine brake fern, the arsenic accumulation ratio for the red-brownish tailings was 6, 275.9 while the ratio for the grey-green tailings was 10, 246.3. In comparison, the accumulation ratios for zinc were 0.92 and 1.31, respectively. This proves that the Chinese brake fern is a hyperaccumulator of arsenic and has tolerance for the other metals in the tailings.
The reddish-brown tailings, which dominate most of the fern and papyrus zone, had a slightly alkaline pH of 8.19 while the grey-green tailings had a pH of 7.23. The concentration of organic carbon, carbonate carbon, and total sulphur were much higher in the contaminant-rich reddish-brown tailings than in the grey-green tailings. The reddish-brown tailings are rich in iron but also contain high concentrations of copper and cobalt which suggests that the reddish-brown tailings were probably formed by the dumping of ore processing waste. In contrast, the low concentration of contaminants in the grey-green tailings suggests that it is formed by the reduction of the reddish-brown tailing during the rainy season. With the use of the DTPA and TEA extraction method, the amount of plant-available metals and arsenic showed similar trends in both tailings types. For the reddish-brown tailings, the ascending order of plant-available contaminants were iron, arsenic, copper, cobalt, manganese and zinc. While in the grey-green tailings the order varied slightly with iron, arsenic, cobalt, copper, manganese, and zinc. The researchers suggested that the concentration of plant-available arsenic, copper, cobalt, manganese, and zinc increases proportionally with the total concentrations in the tailings. However, the authors asserted that the DTPA and TEA extraction method was designed for the determination of metals and therefore may not have been efficient in the determination of arsenic. They therefore used sequential extraction and found the arsenic extraction levels to be 10–15% while the DTPA and TEA only established them at 1.0–1.5%.
The mean concentration of arsenic in the Chinese brake fern was found to be high in the reddish-brown tailings and even higher in the grey-green tailings. This may be as a result of the linear uptake of arsenic at lower concentrations and then the levelling off of uptake at higher concentrations. This suggests that the Chinese brake fern has an avoidance mechanism which protects its system from high concentrations of arsenic. Previous investigations suggest that high levels of arsenic inhibit the phosphate pathway used to take up arsenic and may explain the results. The optimum pH for arsenic uptake by the Chinese brake fern is 6.5 and decreases rapidly with alkalinity which suggests that the slight alkalinity of the reddish-brown tailings may have also accounted for the higher arsenic concentration of plants in the grey-green tailings. The arsenic may have also been competing for uptake with the higher concentration of phosphate in the reddish-brown tailing.
The higher concentration of arsenic in the reddish-brown tailings resulted in a bioaccumulation factor of 18 compared to that of 184 of the grey-green tailings. Although there was a vast difference in bioaccumulation factors, both the tailings had similar concentrations of arsenic in their plants, which suggests that the BF does not account for actual accumulation but rather reflects the concentration of arsenic in the tailings. Concentrations of metals in the fronds in both types of tailings decreased in the following order: iron, copper, manganese, cobalt, and zinc. The BF of each metal negatively correlated with its concentration in the plants. Much like the BF of arsenic, the BFs of the above mentioned metals were higher in the grey-green tailings with the exception of manganese. The high concentration of copper and cobalt found in the tailings pond may have been preventing the uptake of the other metals because the two types of tailings were similar despite different values of contaminants. The plaques or hydroxide and carbonate accumulation on the roots of the Chinese brake fern may have also decreased the amount of metals taken up by the plants.  Compared to the concentration obtained from the fronds, the concentrations established in the leaves of the umbrella plant were substantially lower. Much like the BFs of the Chinese brake fern, there was no positive correlation between BF and the concentration of the contaminant in the plant.
The results of Kříbek et al. show that the Chinese brake fern is a hyperaccumalator of arsenic and is highly tolerant of the many metals contained in the Zambian Copperbelt tailings. The Chinese brake fern may also have a true tolerance to arsenic which means arsenic has no effect on the internal functions of the plant. Unlike many wetland plants, the Chinese brake fern does not trap metals and contaminants in its roots but rather in its fronds which suggests that it could be harvested and continuously grown to decontaminate mining areas. This suggests that the fern could be used for the remediation of tailings ponds across Zambia and in other mining countries. The industrial waste dumping of one element is rare. Rather, dumped industrial waste usually contains a range of heavy contaminants, so plants such as the Chinese brake fern which can accumulate and tolerate the wider ranges of contaminants will be the most efficient at remediating them. The authors emphasize the need for further investigation of the long-term effects that the contaminants have on growth, germination, and other plant functions of the Chinese brake fern. The value of hyperaccumulating plants for mining countries means that these further investigations should be given high priority as the plants could decontaminate mining areas for many other organisms including humans.

Human Mercury Exposure Associated with Small-Scale Gold Mining in Burkina Faso

In many developing countries, governments are yet to formalize or are in the process of formalizing small-scale gold mining and as a result, no substantial guidelines have been implemented to regulate the processes involved in artisanal mining. Therefore, the use of mercury in the extraction process is a cause for concern in terms of environmental toxicity as well as the health repercussions for humans. Tomicic et al. (2011) assessed the mercury exposure and attempted to uncover the factors determining f mercury exposure in various gold mining communities in Burkina Faso. The eight gold mining communities chosen were largely populated with people directly and indirectly affected by mining activity, and all participated in a medical exam which included a questionnaire. Ninety-three directly affected people were categorized as most susceptible to exposure and had their urine tested for mercury.  The researchers found that 69% of the urine samples exceeded the American Conference of Industrial Hygienists biological exposure index and some of the samples were over 10 times the index standard. A third of the susceptible group displayed less than three symptoms associated with mercury exposure while half of the groups suffered from at least five associated symptoms. The authors found that the major determinant in mercury exposure was not the physical handling of mercury but rather the inhalation of mercury vapors during the refining process. The researchers suggest that advice from developed countries would help developing countries establish cleaner small-scale mining processes.—Monkgogi Otlhogile
Tomicic C., Vernez D., Belem T., Berode M., 2011. Human mercury exposure associated with small-scale gold mining in Burkina Faso. International Archives of Occupational and Environmental Health 84, 539–546.

            The artisanal gold mining process usually includes eight steps including the grinding of gold ore into a powder, the washing and sieving of the impure gold ore, the addition of liquid mercury which attracts gold to form an ‘amalgam’, and separates the gold from the impurities in the ore. Finally, the amalgam is placed in an oven and heated until the mercury evaporates and leaves gold behind. Tominic et al. studied the effect of the above-mentioned process on the mining population by examining 1,090 participants in Poushgin, Zinigma, Bouda, Mossobadadougou, Fandojora, Safané and Bagassi for any health effects induced by mercury exposure. Due to the neural, renal, and pulmonary effects of mercury, the medical questionnaire included symptoms such as trembling, chest pains, and dizziness. The susceptible group’s urine samples were tested for albumin and the total urinary mercury concentrations were determined by atomic absorption spectrometry. From the medical questionnaire, the scientists generated exposure determinants which along with the symptoms and total urinary mercury concentrations underwent statistical analysis such as chi-square to prove or disprove their correlation with mercury exposure. Some of the determinants included the gold mine site, which part of the mining process the person took part in, skin contact, and the use of protective equipment.                                                                               The researchers found that after creatinine adjustment, the 93 urine samples ranged from 4.3 to 1, 707 µg/g-Cr with an average of 194.5 µg/g-Cr. Sixty-nine percent of the urine samples exceeded the American Conference of Industrial Hygienists biological exposure index of 35 µg/g-Cr which suggested that excessive mercury exposure is proliferating in the small-scale mining operational sites in Burkina Faso. The authors do assert that their creatinine correction seems to have corrupted a couple of their values but did not exclude them from the study.  From the 93 urine samples, eight of the workers were concerned with the grinding of the gold ore, 33 were involved in ore amalgamation, and 52 were involved in refining the gold. Using the Kruskal-Willis rank test, the researchers saw a significant difference in the urinary mercury levels of all three work groups. The grinding ore workers had the lowest levels of mercury because they had minimal contact with mercury. The amalgamation group exhibited higher levels of mercury because of their direct contact with mercury while the gold refiners exhibited the highest levels of mercury as a result of the inhalation of mercury during the refining process.                                                                         After statistical analysis, the researchers found that six factors were contributing significantly to mercury exposure in Burkina Faso. The factors were age, the occupation of gold refiner, the packaging and heating of mercury, and the Safané and Zinigma sites. The authors found that the heating and inhalation of mercury vapor was a huge factor in the urinary mercury levels which would explain why the gold refiners exhibited the highest levels of mercury in their urine samples. Among the 93 workers who were most susceptible to mercury exposure, headaches, dizziness, chest pain, fatigue, and trembling were the most common mercury associated symptoms. A third of the subgroup displayed less than three mercury defined symptoms while nearly half of the group exhibited five of those symptoms. Among the 779 directly affected participants, the most common symptoms were headaches, dizziness, chest pain, vision disorder and a persistent cough. The researchers found a positive association between ore washers and gold refiners and trembling. They found a positive correlation between heating mercury and chest pain. They also found a positive association between urinary mercury levels and difficulty in grabbing. Even though nearly half of the subgroup had albumin in their urine, there was no association between urinary mercury levels and the presence of albumin.                                                                                                               Though the results of Tomicic et al. suggest that a majority of the gold mine population in Burkina Faso is suffering from mercury-induced health complications, the authors suggest that other external factors may have swayed their data. The lack of a strong association between urinary mercury and symptoms may be caused by the absence of severely sick workers on the sites they surveyed. The researchers suggest that certain health abnormalities such as chest pain and the presence of urinal albumin can also be attributed to dust exposure, other working conditions, and even infectious diseases. They blame this ambiguity on a lack of a control group. However, the authors are confident that their results can be used for the improvement of working conditions in artisanal mining sites in developing countries. The authors believe that strategies such as the recycling of mercury in the amalgamation process and the implementation of international guidelines will reduce the effects of mercury on human health.  

Integrated Acid Mine Drainage Management Using Fly Ash

As the largest producer of coal and electricity in southern Africa, South Africa finds herself in desperate need of efficiently alleviating the impacts of mining and power plants on her environment. Acid mine drainage (AMD) refers to the creation and movement of acidic water saturated with metals which originates from operational and closed coal and metal mines. Fly ash (FA) is an alkaline residue of coal combustion obtained from power plants which contains high concentrations of various metals. As a result of the negative effects of both fly ash and acid mine drainage, Vadapalli et al. (2012) created and tested an efficient zero-waste system in an attempt to recycle the by-products. The researchers intended to neutralize the acid mine drainage with fly ash and test the viability of the solid residue from the previous experiment as a possible filler for the excavated mining sites. They also attempted to synthesize zeolite-P from the AMD-FA mixture. Zeolite-P has a considerable industrial and commercial value as well as the ability to further clean the neutralized water. Vadapalli et al. found that fly ash was a significant neutralizer of acid mine drainage as it removed high levels of major contaminants. Though the solid residue did not have the required strength to be used as a filler, the researchers hypothesized that increased concentrations of cement and/or a longer setting time would increase strength. Even though the zeolite-P synthesis was faulty in terms of yield, they found that zeolite-P was able to ‘polish’ or further clean the water obtained from the AMD-FA treatment of selective elements. These results could allow South Africa access to a cost-effective waste management system —Monkgogi Otlhogile
Vadapalli, V R K., Gitari, M W., Petrik L F., Etchebers O., Ellendt A., 2012. Integrated acid mine drainage management using fly ash.  Journal of Environmental Science and Health: Toxic/Hazardous Substances and Environmental Engineering 47, 60–69.

            Vadapalli et al. used acid mine drainage samples from a coal mine and fly ash samples from a power plant in the Mpumalanga Province in South Africa. Both the fly ash and the acid mine drainage samples were analysed for the concentrations of various elements. Various ratios of AMD and FA (3:1, 2.5: 1, 2:1, and 1.5:1) were mixed and stirred for six hours. The pH and the Electrical Conductivity (EC) of the solutions were measured at different time intervals during the six hours. The solid residue tested as a filler was obtained by a 4:1 ratio of the AMD and FA. After decantation, the residue had water and 3% ordinary Portland cement (OPC) added to it. Much like cement, the solid residue mixture was allowed to settle or ‘cure’ in tubes for a period of 410 days during which strength and elasticity were tested. The zeolite-P was synthesized by obtaining 3:1 solid residue and then drying and crushing it. The crushed solid residue was added to sodium hydroxide, aged, and added to pure water. The product then underwent a thermal treatment and was rinsed until the rinse water had a pH of 9. The solid product was dried and then evaluated using x-ray analysis. This product was then used to clean the previously neutralized water by adding the solid product to the water at a ratio of 1:100 for an hour. The water was filtered and analysed for various elements.
            Vadapalli et al. found that the introduction of FA almost immediately raised the pH of all the AMD-FA mixtures and continued to increase the pH after a buffer region during which the pH remained constant for a significant amount of time. During this buffer region, the reaction of major components of AMD and water such as iron took place which then increased the pH. However, because these reactions can only take place at a pH of 4–7, the pH remained constant as the reactions were taking place and then increased as the products of the reactions were released into the system. They also found that the final pH was directly proportional to the amount of FA added which leads to the conclusion that it was the FA that was responsible for the pH change. The electrical conductivity of the almost all the mixtures almost immediately decreased and after the same buffer region as the pH values, there was a gradual decline in EC. However, the researchers observed an EC increase in the 1.5:1 AMD-FA mixture at the end of the experiment as a result of transient sulphate. The researchers found that the contaminant removal rate except for aluminium and sulphate was directly proportional to the amount of FA added to the AMD. Though not all of the ratios were proportional, the FA particles played a major role in the significant removal of iron, sulphate, aluminium, manganese, magnesium, zinc, nickel, copper, and lead. Magnesium had an initial concentration of 2661 ± 35 and was decreased in the 1.5:1 mixture to 1.5 ± 0.02 while iron had an initial concentration of 5600 ± 81 and was decreased in the 1.5: 1 mixture to 5 ± 0.7. This showed that FA had a significant contaminant removal rate when added to AMD.
            After measuring the strength and elasticity of the solid residue mixture over a 410 day period, the scientists found that the mixture’s elasticity and strength increased steadily. However, the elasticity had a temporary decrease after 180 days. At the end of the 410 days, the solid residue mixture displayed strength of approximately 0.30 MPa which fell short for the mixture to be used a filler for the excavation sites. However, the scientist suggest that using more ordinary Portland cement, increasing curing time, and a lower ratio of AMD to FA could increase the strength of the solid residue mixture. In the final stages of the system, the ratio of aluminium and silicon used in the synthesis process determined that the scientists had created zeolite-P. However, during the x-ray analysis, the scientists found that there was a significant amount of mullite which represented the unconverted fly ash.  This suggests that the authors had not picked the optimum conditions for the complete synthesis of zeolite-P. As a secondary treatment agent for the neutralized water, zeolite-P was able to selectively remove elements that the FA was unable to effectively remove. Though, zeolite-P added sodium and silicone to the water, it was able to slightly decrease pH as well as significantly remove calcium, strontium, iron, manganese, vanadium, beryllium, and barium. The percentage removal ranged from the 34% removal of calcium to the 99% removal of manganese. The cumulative results of the authors’ study points to a zero-waste system which would effectively manage the by-products of mining and power plants in South Africa and other countries with the same environmental problems. 

Assessment of Mercury Pollution in Rivers and Streams around Artisanal Gold Mining Areas of the Birim North District of Ghana

In many sub-Saharan countries where poverty and an abundance of natural resources seem to coexist, it comes as no surprise that legal and illegal artisanal mining is on the rise as the poor seek a source of income. However, while relatively lucrative, because of unsophisticated extraction techniques, small-scale gold miners release about 1,350 tons of mercury into water bodies annually. Ghana, the second greatest producer of gold in Africa, releases close to five tons of mercury per year.  Nartey et al. (2011) measured the mercury levels up and downstream rivers, streams, boreholes and, sediments during rainy and dry seasons in the Birim North District of Ghana where small-scale mining is common. The samples were then compared to the Environmental Protection Agency’s (EPA) mercury guideline value for sediments and World Health Organization’s (WHO) mercury guideline limit for drinking water. All the samples showed a significant increase in mercury during the wet season while the samples downstream also showed a significant increase in mercury. The researchers found that the mercury levels in all but one water sample did not exceed the WHO’s guideline limit. However, all the sediment samples exceeded the EPA’s guideline value. Though the mercury levels in the water samples were within WHO standards, the sediment levels and the fluctuations in mercury levels between the wet and dry seasons were causes of concern. —Monkgogi Otlhogile
Nartey, V K.,Klake, R K., Hayford, E K., Doamekpor, L K., Appoh, R K., 2011. Assessment of mercury pollution in rivers and streams around artisanal gold mining areas of the Birim North District of Ghana. Journal of Environmental Protection 2, 1227–1239.

           
Nartey et al.picked six rivers and streams—Pra, Nwi, Suten, Nyanoma, Nkwasua and Tainsu—which were strategically placed within range of small-scale mining activity. The scientists then choose sites up and downstream from the mining activity to obtain river, stream, and sediment samples. These samples were taken from the middle of each water body. They also took water samples from six boreholes which were considered severely affected by mining activity. Over a 12 month period—during which the district experienced two rainy seasons—the researchers collected 300 ml of water and 30 g of sediment from each one their designated sites. The water samples were treated with stabilizers and spectroscopy was used to measure the amount of light absorbed by the water samples. The absorbance values of the water samples were used to ascertain the total mercury concentrations of each sample site. The sediment samples were dried, ground, heat treated, and diluted with water. The solutions were analysed using an atomic absorption spectrometer which can determine the concentration of an element such as mercury in a solid state such the sediment.
            All of the sample sites downstream from the mining activity showed higher concentrations of mercury than the upstream sites because of the flow of the water and mercury. The mercury concentrations of the water samples taken from the rivers and streams during the wet season were significantly lower than the samples taken during the dry season. The authors suggest that this could have been influenced by increased mining during dry seasons, though they did not observe a significant increase in small-scale mining during the 12 month period.  They also suggest that the evaporation of surface water that occurs during the dry season may have caused an increase in the mercury concentrations. Although there were significant differences in the concentration of the upstream and downstream samples, none of the river and stream samples exceeded the WHO’s guideline limit of 1µg/L except for the Tainsu downstream sample taken during the wet season with a concentration of 1.343 µg/L. However, as a result of previous samples taken near the River Pra which showed higher concentrations of mercury, the authors had reason to believe that either the samples had been mishandled and miscalculated, or had been affected by the operational status of the mining sites. 
            Unlike the river and stream samples, the boreholes samples did not show a significant difference in mercury levels between the wet and dry seasons because unlike surface water, the underground water of boreholes is not immediately diluted by rain water. None of the borehole samples exceeded the WHO’s guideline limit even though the Nyafoman borehole had a moderately high total mercury concentration of 0.619 µg/L. Much like the other water samples, previous samples led the researchers to believe that their collection methods and the operational status of the mining sites near the boreholes may have had an effect on the significantly lower mercury levels they obtained.
            Though the authors concede that high mercury concentrations in sediment have no direct human impact, they suggest that the sediment’s role in aquatic ecosystems is a cause of concern. Not only can sediment concentrations act as water quality indicators, but sediment pollution also affects the food chains we take part in through fishing. Because of the previously mentioned reasons, the total mercury concentrations of the sediment samples during the wet season were significantly lower than the samples taken during the dry season. The minimal river mixing during the dry season, which keeps the mercury in the sediment, also plays a role in the fluctuation of mercury levels. In the sediment samples, all but one of the total mercury concentrations were above the EPA guideline value of 0.2 mg/kg. The Tainsu sediment had the highest total mercury concentration at 1.881 mg/kg during the dry season. A comparison of data between previous samples and the study’s sediment samples showed the study samples to have higher total mercury concentrations. This suggests that the direct dumping of mining waste into water bodies may be causing the settling of mercury in the sediment. 

Impacts of Surface Gold Mining on Land Use Systems in Western Ghana

Conflict will invariably occur between mining companies and local rural communities especially in developing countries as mining displaces people, causes land and water degradation, and ultimately changes the social and economic dynamics of the area. Schueler et al. (2011) studied the effects surface gold mining had on the land cover and land use of a mining district in western Ghana. Using Landsat satellite images, field interviews, and field mapping, the authors were able to quantify the deforestation, farmland loss, and expansion that occurred between 1986 and 2002 as result of surface gold mining in the Wassa West District of Ghana. Schueler et al. found surface mining to blame for 58% of deforestation and 45% of farmland loss in the mining concessions. Furthermore, as a result of inadequate compensation schemes for the rural farmers and displacement, gold mining caused discontent in the communities, further deforestation for new farm land, agricultural escalation, and even more land degradation. The authors suggest that the opportunity cost of surface gold mining in Ghana may be greater than initially thought. —Monkgogi Otlhogile
Schueler, V., Kuemmerle, T., Schröder, H., 2011. Impacts of surface gold mining on land use systems in western Ghana. Ambio: A Journal of the Human Environment 40, 528–539.

Schueler et al. studied the Damang, Bogoso-Prestea and Tarkwa mining concessions in the Wassa West District. They obtained and adjusted two satellite images from NASA of the Wassa West District; one from December 29, 1986 and the other from January 15, 2002. Using a Global Position System (GPS) receiver and the aid of local residents, the researchers physically mapped the mining, farmland, and forests areas, and documented the land cover type of close to 19, 000 ha of the Wassa West District. To accurately map the land cover changes, the scientists stacked the satellite images and categorized the land into deforestation, farmland loss, permanent farmland, permanent forest, permanent mine, and farmland expansion classes. Finally, the scientists held a workshop in a typically impacted mining village to assess the community’s reaction to the gold mining. They also held 35 interviews with government representatives and agricultural private companies and 40 interviews with farm representatives. This allowed the authors access to the immediate social, environmental and economic impacts of the change in land cover and land use they had observed.
The authors found that surface gold mining had resulted in massive land cover change in all three of the areas they studied. In 1986, mining sites only accounted for 0.2% of the land but in 2002 the sites had taken over 41.9% of the land. Over the sixteen year period, 3,168 ha of forest and 4,935 ha of farmland in the three concessions was lost to the surface gold mining companies. Additionally, 3,067 ha of land was converted from forest to farmland by displaced farmers. During the interviews, Schueler et al. noted the lack of a consistent process for compensation as well as a lack of knowledge of the consequences of gold mining among rural farmers. Most of the farmers and community members of the Wassa West District viewed the impact of gold mining as negative as a result of the insufficient compensation they received, farmland loss and the degradation of clean water. In an effort to supplement their income, some disgruntled farmers have even become small-scale miners. The authors found that though government officials and NGO representatives were concerned with farmland allocation, land use planning in the district was dismal and resulted in additional land pressure.
The authors suggest one of the root causes of the diverse impacts of gold mining to be the lack of a neutral arbitrator during compensation negotiations. The inadequate compensations caused the discontented farmers to either take up mining themselves or to continue vigorous farming elsewhere. The small-scale miners have faced conflict with bigger mining companies because of the threat that they each pose to each other. The small scale miners also have a harsher effect on the environment as a result of the mercury used in their mining process and this has caused even more land degradation. The remaining farmers, however, did damage as they cleared forest for farmland. As a result of scarce farmland, many farmers increased cultivation causing land degradation, which induced further deforestation. The authors point to this cycle as the reason for the forest loss, within and even outside the mining concessions. The authors indicate spatial planning would break this cycle as it would reconcile farmland loss and decrease the pressure on the land in the Wassa West District. Though surface gold mining is profiting the Ghanaian economy, the social, economic, and health disadvantages that have been put upon local communities seem to have caused a cascade of problems which will have to be mitigated at the government level. 

Impacts of Surface Gold Mining on Land Use Systems in Western Ghana

Conflict will invariably occur between mining companies and local rural communities especially in developing countries as mining displaces people, causes land and water degradation, and ultimately changes the social and economic dynamics of the area. Schueler et al. (2011) studied the effects surface gold mining had on the land cover and land use of a mining district in western Ghana. Using Landsat satellite images, field interviews, and field mapping, the authors were able to quantify the deforestation, farmland loss, and expansion that occurred between 1986 and 2002 as result of surface gold mining in the Wassa West District of Ghana. Schueler et al. found surface mining to blame for 58% of deforestation and 45% of farmland loss in the mining concessions. Furthermore, as a result of inadequate compensation schemes for the rural farmers and displacement, gold mining caused discontent in the communities, further deforestation for new farm land, agricultural escalation, and even more land degradation. The authors suggest that the opportunity cost of surface gold mining in Ghana may be greater than initially thought. —Monkgogi Otlhogile

Schueler, V., Kuemmerle, T., Schröder, H., 2011. Impacts of surface gold mining on land use systems in western Ghana. Ambio: A Journal of the Human Environment 40, 528–539.

Schueler et al. studied the Damang, Bogoso-Prestea and Tarkwa mining concessions in the Wassa West District. They obtained and adjusted two satellite images from NASA of the Wassa West District; one from December 29, 1986 and the other from January 15, 2002. Using a Global Position System (GPS) receiver and the aid of local residents, the researchers physically mapped the mining, farmland, and forests areas, and documented the land cover type of close to 19, 000 ha of the Wassa West District. To accurately map the land cover changes, the scientists stacked the satellite images and categorized the land into deforestation, farmland loss, permanent farmland, permanent forest, permanent mine, and farmland expansion classes. Finally, the scientists held a workshop in a typically impacted mining village to assess the community’s reaction to the gold mining. They also held 35 interviews with government representatives and agricultural private companies and 40 interviews with farm representatives. This allowed the authors access to the immediate social, environmental and economic impacts of the change in land cover and land use they had observed.

The authors found that surface gold mining had resulted in massive land cover change in all three of the areas they studied. In 1986, mining sites only accounted for 0.2% of the land but in 2002 the sites had taken over 41.9% of the land. Over the sixteen year period, 3,168 ha of forest and 4,935 ha of farmland in the three concessions was lost to the surface gold mining companies. Additionally, 3,067 ha of land was converted from forest to farmland by displaced farmers. During the interviews, Schueler et al. noted the lack of a consistent process for compensation as well as a lack of knowledge of the consequences of gold mining among rural farmers. Most of the farmers and community members of the Wassa West District viewed the impact of gold mining as negative as a result of the insufficient compensation they received, farmland loss and the degradation of clean water. In an effort to supplement their income, some disgruntled farmers have even become small-scale miners. The authors found that though government officials and NGO representatives were concerned with farmland allocation, land use planning in the district was dismal and resulted in additional land pressure.

The authors suggest one of the root causes of the diverse impacts of gold mining to be the lack of a neutral arbitrator during compensation negotiations. The inadequate compensations caused the discontented farmers to either take up mining themselves or to continue vigorous farming elsewhere. The small-scale miners have faced conflict with bigger mining companies because of the threat that they each pose to each other. The small scale miners also have a harsher effect on the environment as a result of the mercury used in their mining process and this has caused even more land degradation. The remaining farmers, however, did damage as they cleared forest for farmland. As a result of scarce farmland, many farmers increased cultivation causing land degradation, which induced further deforestation. The authors point to this cycle as the reason for the forest loss, within and even outside the mining concessions. The authors indicate spatial planning would break this cycle as it would reconcile farmland loss and decrease the pressure on the land in the Wassa West District. Though surface gold mining is profiting the Ghanaian economy, the social, economic, and health disadvantages that have been put upon local communities seem to have caused a cascade of problems which will have to be mitigated at the government level.

Impacts of Surface Gold Mining on Land Use Systems in Western Ghana

Conflict will invariably occur between mining companies and local rural communities especially in developing countries as mining displaces people, causes land and water degradation, and ultimately changes the social and economic dynamics of the area. Schueler et al. (2011) studied the effects surface gold mining had on the land cover and land use of a mining district in western Ghana. Using Landsat satellite images, field interviews, and field mapping, the authors were able to quantify the deforestation, farmland loss, and expansion that occurred between 1986 and 2002 as result of surface gold mining in the Wassa West District of Ghana. Schueler et al. found surface mining to blame for 58% of deforestation and 45% of farmland loss in the mining concessions. Furthermore, as a result of inadequate compensation schemes for the rural farmers and displacement, gold mining caused discontent in the communities, further deforestation for new farm land, agricultural escalation, and even more land degradation. The authors suggest that the opportunity cost of surface gold mining in Ghana may be greater than initially thought. —Monkgogi Otlhogile

Schueler, V., Kuemmerle, T., Schröder, H., 2011. Impacts of surface gold mining on land use systems in western Ghana. Ambio: A Journal of the Human Environment 40, 528–539.

Schueler et al. studied the Damang, Bogoso-Prestea and Tarkwa mining concessions in the Wassa West District. They obtained and adjusted two satellite images from NASA of the Wassa West District; one from December 29, 1986 and the other from January 15, 2002. Using a Global Position System (GPS) receiver and the aid of local residents, the researchers physically mapped the mining, farmland, and forests areas, and documented the land cover type of close to 19, 000 ha of the Wassa West District. To accurately map the land cover changes, the scientists stacked the satellite images and categorized the land into deforestation, farmland loss, permanent farmland, permanent forest, permanent mine, and farmland expansion classes. Finally, the scientists held a workshop in a typically impacted mining village to assess the community’s reaction to the gold mining. They also held 35 interviews with government representatives and agricultural private companies and 40 interviews with farm representatives. This allowed the authors access to the immediate social, environmental and economic impacts of the change in land cover and land use they had observed.

The authors found that surface gold mining had resulted in massive land cover change in all three of the areas they studied. In 1986, mining sites only accounted for 0.2% of the land but in 2002 the sites had taken over 41.9% of the land. Over the sixteen year period, 3,168 ha of forest and 4,935 ha of farmland in the three concessions was lost to the surface gold mining companies. Additionally, 3,067 ha of land was converted from forest to farmland by displaced farmers. During the interviews, Schueler et al. noted the lack of a consistent process for compensation as well as a lack of knowledge of the consequences of gold mining among rural farmers. Most of the farmers and community members of the Wassa West District viewed the impact of gold mining as negative as a result of the insufficient compensation they received, farmland loss and the degradation of clean water. In an effort to supplement their income, some disgruntled farmers have even become small-scale miners. The authors found that though government officials and NGO representatives were concerned with farmland allocation, land use planning in the district was dismal and resulted in additional land pressure.

The authors suggest one of the root causes of the diverse impacts of gold mining to be the lack of a neutral arbitrator during compensation negotiations. The inadequate compensations caused the discontented farmers to either take up mining themselves or to continue vigorous farming elsewhere. The small-scale miners have faced conflict with bigger mining companies because of the threat that they each pose to each other. The small scale miners also have a harsher effect on the environment as a result of the mercury used in their mining process and this has caused even more land degradation. The remaining farmers, however, did damage as they cleared forest for farmland. As a result of scarce farmland, many farmers increased cultivation causing land degradation, which induced further deforestation. The authors point to this cycle as the reason for the forest loss, within and even outside the mining concessions. The authors indicate spatial planning would break this cycle as it would reconcile farmland loss and decrease the pressure on the land in the Wassa West District. Though surface gold mining is profiting the Ghanaian economy, the social, economic, and health disadvantages that have been put upon local communities seem to have caused a cascade of problems which will have to be mitigated at the government level.