Artisanal Mining Sites Research Articles

Extent and drivers of land productivity degradation at the territorial level in Eastern DR Congo

Land degradation is a global environmental problem that affects the livelihoods of communities. Understanding the extent and causative factors of this phenomenon is important to design the cause-targeted strategies to cope with this problem. This study aimed to assess the effects of biophysical and socio-economic factors on the occurrence of land productivity degradation at the territorial level in Eastern DR Congo, using the Kalehe territory as a case study. The land productivity dynamics were determined based on the trend analysis of Landsat-based NDVI annual composites over the 1987-2020 period. Additionally, a binary logistic regression model was developed to identify the determinant factors and to map the susceptibility of this degradation at the territorial level. The results revealed that 31.25% (1303.175 km2) of the territory had experienced a decrease in land productivity, with 10.8% (453.83 km2) characterized by a significant decrease at the confidence level of 90%, representing the hotspots area of land productivity degradation where conservation actions should be prioritized. This decrease in land productivity is location-specific as it depends on the land cover types and health zones. It is likely to occur at high altitudes, in areas close to artisanal mining sites, rivers, and administrative centers. These results imply that policy interventions to cope with the problem of land productivity degradation should be developed following the heterogeneity of the landscape, and sustainable land management practices that take into account both the biophysical and socio-economic drivers of land degradation should be implemented in this region to achieve the land degradation neutrality by 2030.

Epidemiological profile of malaria in a rural community in the Amazon, Mato Grosso State, Brazil, 2011

BackgroundMore than 95% of malaria transmission in Brazil occurs in the Legal Amazon Region, which in 2010 recorded around 333,429 cases reported in the Epidemiological Surveillance Information System-Malaria (Sivep_malaria), presenting an annual parasitic incidence (IPA) of 13.1 cases/1000 inhabitants.MethodsThis was a descriptive study that measured the community prevalence of Plasmodium infection and its relationship with land use in Três Fronteiras District, Colniza Municipality, Mato Grosso State. Data were collected during household visits in July 2011, with blood collection from finger pricks for the preparation of thick smear slides, and completion of a standardized case notification form. A georeferenced database was analysed, with land use evaluated as categorical variables. A kernel density map was built to show the density of cases and their location.ResultsOf the 621 respondents, 68(11%) had Plasmodium infection: 39 (57.4%) with Plasmodium vivax, 27(39.7%) with Plasmodium falciparum and two (2.9%) with mixed infections. Among infected individuals, 49 (72.1%) were men. Cases of malaria were distributed over the district, with greater occurrence of cases per household in open areas close to the mining company and artisanal mining sites. The was a greater density of cases located in the gold mining region.ConclusionTransmission of malaria in Três Fronteiras District has a heterogeneous distribution. Individuals residing in mining and timber extraction sites have increased occurrence of Plasmodium infection.

“Hg distribution and accumulation in soil and vegetation in areas impacted by artisanal gold mining in the Southern Amazonian region of Madre de Dios, Peru.”

Artisanal and small-scale gold mining (ASGM) is the primary global source of anthropogenic mercury (Hg) emissions. It has impacted the Amazon rainforest in the Peruvian region of Madre de Dios. However, few studies have investigated Hg's distribution in terrestrial ecosystems in this region. We studied Hg's distribution and its predictors in soil and native plant species from artisanal mining sites. Total Hg concentrations were determined in soil samples collected at different depths (0–5 cm and 5–30 cm) and plant samples (roots, shoots, leaves) from 19 native plant species collected in different land cover categories: naked soil (L1), gravel piles (L2), natural regeneration (L3), reforestation (L4), and primary forest (L5) in the mining sites. Hg levels in air were also studied using passive air samplers. The highest Hg concentrations in soil (average 0.276 and 0.210 mg kg−1 dw.) were found in the intact primary forest (L5) at 0–5 cm depth and in the plant rooting zones at 5–30 cm depth, respectively.Moreover, the highest Hg levels in plants (average 0.64 mg kg−1 dw) were found in foliage of intact primary forest (L5). The results suggest that the forest in these sites receives Hg from the atmosphere through leaf deposition and that Hg accumulates in the soil surrounding the roots. The Hg levels found in the plant leaves of the primary forest are the highest ever recorded in this region, exceeding values found in forests impacted by Hg pollution worldwide and raising concerns about the extent of the ASGM impact in this ecosystem. Correlations between Hg concentrations in soil, bioaccumulation in plant roots, and soil physical-chemical characteristics were determined. Linear regression models showed that the soil organic matter content (SOM), pH, and electrical conductivity (EC) predict the Hg distribution and accumulation in soil and bioaccumulation in root plants.

Contribution of early succession regeneration plants to heavy metal remediation in abandoned Artisanal small-scale mining sites in Ghana

Artisanal Small-Scale mining (ASM) is a major land use activity in Ghana. Despite its tremendous contribution to livelihoods, ASM is largely unregulated in the country, illegally operated, leaving most mined out sites unrehabilitated. In this study, we explored the extent to which early succession naturally regenerating plants on two abandoned illegal artisanal small scale mined-out sites (Chamfi and Alluvial types) remediate heavy metals. The study was undertaken in three districts of the Western Region of Ghana. Plots were randomly established in the alluvial, chamfi and reference (control) sites. Within each plot, samples of soil and naturally regenerating plants were collected for determination of bioaccumulation potential, translocation and contamination factor of cadmium (Cd), arsenic (As), lead (Pb), and mercury (Hg) using the Atomic Absorption Spectrophotometer. The results revealed that the concentration of As, Cd, Hg, Pb from soil samples, as well as roots and shoots of the plants collected from the two mined sites were significantly higher than the concentrations in the samples from the control plots. Our results show that heavy metal removal is more significant in plants at the alluvial mined soils than those at the chamfi sites. C. pubescens, C. odorata, and M. pudica were observed to be better cadmium translocators than the other vegetations sampled. Furthermore, plants at the alluvial sites recorded higher Bioaccumulation Factor (BF) in the roots than those at the chamfi sites for lead and arsenic. The study implies that natural regeneration of early successional species can promote contaminant removal on abandoned artisanal mine sites. They however vary in their capacity to accumulate different metals on abandoned soils. Within the context of illegal ASM prevalence, our results suggest that efforts should be made to encourage and minimize disturbances to the growth of early succession plant species as short-term alternative measures in abandoned artisanal mined sites, where reclamation is often neglected.

Does the education system matter? Exploring in-depth joint school attendance, hazardous and non-hazardous activities in artisanal and small-scale mining in the Democratic Republic of the Congo

PurposeThis paper explores the deconstruction of child labour in artisanal and small-scale mining (ASM) sites, highlighting different perspectives. Despite the economic benefits to the Democratic Republic of the Congo (DRC), ASM poses challenges, particularly where children are concerned. Methodology: Our study uses a convergent parallel mixed methods approach to interpret qualitative and qualitative data based on the conceptual framework of human capital. Trivariate probit and Tobit models were used for quantitative data and content analysis was employed for qualitative data. We collected primary data by interviewing children involved in artisanal mining activities. Interviews were conducted with consent from the children and their parents or guardians. We adopt snowball sampling due to the lack of a database. The Centre of Expertise on Mining Governance (CEGEMI) developed the data collection instruments in collaboration with Inner City Fund (ICF) International and validated by the United States Department of Labour. FindingsWe found that limited access to education leads to decreased school attendance rates among children, pushing them towards engaging in hazardous and non-hazardous economic activities within the DRC's mining areas. Moreover, excessive working hours negatively impact children's academic performance. Consequently, there is a trade-off between attending school and engaging in child labour at ASM sites in the DRC. LimitationsThis study did not consider domestic activities carried out by children. This could give even more detailed results. Public policy implicationsGovernments and partners must prioritise creating a comprehensive list of hazardous activities for children in the ASM context. Careful conceptualisation is necessary to ensure the clarity and effectiveness of this list. Raising awareness about the merits of removing children from activities related to mining is important for households living in and around ASM sites. Interventions aiming to reduce child labour and increase school attendance in ASM zones must remain mindful of the socio-economic and school infrastructure needs.

Towards sustainable food crop production: Drivers of shift from crop production to mining activities in Ghana's Arable Lands

This study contributes to the observed reduction of arable lands discourse by examining the shift in land use patterns as well as factors influencing farmers' shift from crop production to mining activities. To achieve this, we employed a combination of Geographic Information System (GIS) technology and Cragg's Double Hurdle Econometric Model as analytical tools. Our approach integrates an econometric model of land use with GIS simulations that predict the spatial pattern of land-use change. The results revealed that crop production lands have been converted into artisanal small-scale mining (galamsey) sites, a development which has implications on food security, life on land and effective utilizations of land and water resources. The results also showed that membership in Farmer-Based Organizations (FBOs), access to credit, and low yield of food crops influenced farmers to shift from crop production to participate in mining activities. In addition, the extent of participation in mining was influenced by family size, membership in FBOs, and low crop yield. While mining operations offer substantial economic benefits, it is crucial to strike a balance between land use for mining activities and food crop production. This is because it has the potential to worsen recent hikes in food prices and subsequently leading to rising inflation rates in Ghana. Our findings have implications on achieving multiple SDGs, viz. SDG 2 (Zero Hunger), SDG 6 (Clean Water and Sanitation) and SDG 15 (Life on Land) as minimizing illegal mining helps increase food production as well as protect water bodies and land. We therefore suggest that government should take steps to make credit accessible to farmers by collaborating with financial institutions and also collaborate with Crops Research Institutes to develop high-yielding crop varieties. Future research could focus on exploring the impact of participating in mining activities on the profitability of food crop production in Ghana.

Framing spaces as (il)legitimate: “dirty” cobalt and the (mis)uses of artisanal and small-scale mining sites in south-eastern Democratic Republic of Congo

ABSTRACT As large-scale mining (LSM) companies and other commercial actors capitalise on a demand boom for Congolese cobalt, they have framed artisanal and small-scale mining (ASM) spaces as problematic and illegitimate to make themselves appear “cleaner” than locally legitimate artisanal mining. Firms have emphasised the negative facets of artisanally mined cobalt, characterising their own production as “clean” and problem free. Capitalist actors’ framing of artisanal mining spaces as “illegitimate” or “dirty” is a powerful narrative that produces significant consequences. First, ASM, a minority of total cobalt production, becomes the focus of negative publicity; this framing erases the negative impacts of LSM. In turn, illicit “taxation” by public and private security forces at LSM sites is overlooked despite its systemic, organised nature. Next, the framing obscures the multiple interconnections between ASM and LSM. Finally, the framing of ASM spaces allows capitalist actors to claim these spaces to reshape and “organise” them.

Isolation and Characterization of Heavy Metals Resistant Bacteria in Water Samples from Mambilla Artisanal Mining Site, Nguroje, Taraba State

Isolation and Characterization of Heavy Metals Resistant Bacteria in Water Samples from Mambilla Artisanal Mining Site, Nguroje, Taraba State

Assessment of heavy metal pollution of drinking water sources and staple food cultivars around artisanal mining site in Igade-Mashegu, Niger State, Nigeria

Ecotoxicological studies have been carried out on the precarious effects of heavy metal pollution and exposure attributed to anthropogenic practices such as mining, industrial and agricultural activities, which poses serious health challenges. This study investigated ten (10) heavy metals namely As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb and Zn in one hundred and fifteen samples from water sources and staple food cultivars around Igade mining site in Mashegu Local Government Area of Niger State, North-Central Nigeria, using Atomic Absorption Spectrophotometer (AAS). The result revealed the concentrations of heavy metals in staple food cultivars consumed at Igade to be within the recommended maximum levels as stipulated by WHO/FAO, but As2+ and Cd2+ were higher in legumes (1.510 ± 0.169 mg/kg) and vegetables (1.666 ± 0.154 mg/kg); and cereals (0.328 ± 0.012 mg/kg) and tubers (0.421 ± 0.176 mg/kg) respectively. This implies that the artisanal mining contributed to the exogenous bioaccumulation of these metals in staple food cultivars following the pattern: Fe > Zn > Cu > As > Pb > Cr > Cd > Hg which could accumulate and destroy vital organs thereby affecting human health upon consumption. Also, the mean concentration of the heavy metals in various water sources at Igade mining site decreased in the order Zn > Fe > Cr > Cu > As > Hg > Pb > Cd > Ni. Levels of As, Hg, Pb, Fe, and partly Cr in water sources were observed to be higher than the WHO and NSDWQ recommended standards for drinking water. Thus, their continuous consumption poses potential health risk to inhabitants, and therefore, there is need for the provision of safe alternative water sources; proper sensitization and monitoring of the mining activities to curb health risks and the extent of heavy metal contamination.

Assessment of heavy metal pollution of drinking water sources and staple food cultivars around artisanal mining site in Igade-Mashegu, Niger State, Nigeria

Assessment of heavy metal pollution of drinking water sources and staple food cultivars around artisanal mining site in Igade-Mashegu, Niger State, Nigeria

Salafist violence and artisanal mining: Evidence from Burkina Faso

Armed groups have expanded their presence in the Sahel over the last decade, including in areas with intensive artisanal gold mining. Our understanding of how their presence changes the governance of artisanal mining sites, how it differs from agriculture and pastoralism, and what miners' response is, however, is still limited. In this paper, we examine how Salafist expansion interacts with local socio-political dynamics and impacts agriculture and artisanal mining in Sanmatenga province, Burkina Faso. We find agriculture contracts due to widespread violence against civilians perpetrated by Salafist groups, local militia, and state security actors. In contrast, artisanal mining expands. Local miners perceive Salafist governance on mining sites as more liberal, more inclusive, and economically advantageous. By building output-based legitimacy to secure artisanal miners' cooperation, Salafist groups’ approach so far differs significantly from state-led approaches, which focus on formalisation without tangible benefits for artisanal miners.

Changes in the surface water quality of a tropical watershed in the southeastern amazon due to the environmental impacts of artisanal mining

The expansion of areas of human occupation and the increase in economic activity and deforestation are negatively impacting the Amazon ecosystem. Situated in the Carajás Mineral Province in the southeastern Amazon, the Itacaiúnas River Watershed (IRW) encompasses several active mines and has a historical record of intense deforestation primarily linked with the expansion of pasturelands, but also of urban areas, and mining activities. Industrial mining projects are subjected to strict environmental control, but artisanal mining (ASM; ‘garimpos’) sites have not been controlled, despite their known environmental impacts. In recent years, the opening and expansion of ASM in the IRW for the exploitation of mineral resources (Au, Mn, and Cu) have been remarkable. This study presents evidence of anthropogenic impacts, mainly caused by ASM, on the quality and hydrogeochemical characteristics of the IRW surface water. The hydrogeochemical data sets of two projects carried out in the IRW, during 2017 and from 2020 until present, were used to evaluate these impacts within the region. Water quality indices were calculated for the surface water samples. For the whole IRW, water collected during the dry season tended to yield better quality indicators in comparison to those collected during the rainy season. Two sampling sites at Sereno Creek showed very poor water quality and extremely high concentrations of Fe, Al, and potentially toxic elements over time. From 2016 to 2022, ASM sites increased markedly. Moreover, there are indications that Mn exploitation via ASM in Sereno hill is the main source of contamination in the area. New trends of ASM expansion were observed along the main watercourses, related to the exploitation of Au from alluvial deposits. Similar anthropogenic impacts are registered in other regions of the Amazon and environmental monitoring should be encouraged to assess the chemical safety of strategic areas.

Participative epidemiology and prevention pathway of health risks associated with artisanal mines in Luhihi area, DR Congo

BackgroundHealth issues are associated with artisanal mining in the DR Congo. The scenario is worst when artisanal mining is done informally or with limited material and technical resources.This paper argues that the adoption of healthy practices by artisanal miners might be limited given that it involves unrealistic socio-economic, and administrative aspects and access to health risk prevention means.Making a conceptual framework on the feasibility of revolutionizing artisanal mining practices linked to health risks in the DR Congo requires trans-disciplinary interventions and researches. This case study aims at co-analyzing with actors in the Luhihi artisanal gold mine, the epidemiology of health issues. It also aims at describing the dynamics of resources that mining actors mobilize or think they can mobilize in order to prevent health risks.MethodsA “socio-anthropological” qualitative study with “transdisciplinary methods” was carried out the Luhihi artisanal mining. Data collection tools and methods included an exploratory survey, semi-structured interviews. Focus groups (FG) mixed with proportional piling were used to support the open-ended interview discussions. The actors interviewed were selected by “convenience sampling” and the saturation principle indicated the size of the sampling. In total, 67 persons were interviewed and 5 FG each consisting of 5 to 10 mining actors were organized. Data were triangulated among respondents to ensure their veracity and an “inductive thematic data analysis” was applied.ResultsKey findings are the role of actors involved the organization system at the Luhihi artisanal mining site; a description of a participative epidemiology and determinants of health issues; presentation of the importance of health risks as perceived by mining actors; the constraints in the common illenesses treatment; and opportunities of collective actions for gathering resources required for the organization of healthcare services.ConclusionThe results are translated into a grid of powers and interests in relation to the mobilization of resources for the prevention and treatment of health issues. The dialogue for change regarding the ignorance of the actors to exposure to chemical risks such as to exposure mercury, silica, carbon monoxide, and cyanide also entailed the translation of the results. In addition, an analysis of the ability of artisanal mining actors to implement health risk prevention services was made.

Artisanal Mining and Soil Quality in the Sudano-Sahelian Climate: Case of the Artisanal Mining Site of Yimiougou in Burkina Faso, West Africa

The majority of the population of Burkina Faso lives from agriculture and therefore depends on the land. The main objective of this study is to assess the quality of the soils in the area linked to artisanal mining activities. The methodology adopted consisted in sampling and characterizing the main types of soil. In order to assess the level of soil pollution by artisanal mining, parameters such as the geo-accumulation index (Igeo) and the contamination factor (CF) are calculated. A prediction of acid mine drainage (AMD) was also carried out on samples of mine tailings which are potential sources of pollution of these soils. The results obtained show that the soils in Yimiougou are of nil to low agronomic interest. The Igeo shows that for lead, copper, zinc and arsenic the levels found in the different morphological units are partly attributable to human action and specifically artisanal mining. The values of the contamination factor indicate contamination. Cobalt presents the lowest contamination. For cadmium, the different types of soil are moderately contaminated except for the FITLC type, which has a CF value of 0.50, therefore synonymous with low or absent contamination. The various morphological units studied are very heavily contaminated with zinc, copper, lead and arsenic. The pH and conductivity values indicate that the mine tailings samples are non-acidogenic, therefore not yet oxidized. As for the sulphide contents, they show that only samples S17, S22, S23 and S24 present values that are strictly above the threshold (0.3%) and therefore potentially acid-generating. The comparative study of the acid potential (AP) and the neutralization potential (NP) reveals that the neutralization potentials of the different samples are clearly higher than the acid potentials even for the samples which present a proven acidification potential (S17, S22, S23 and S24). These results show that the mine tailings have the natural capacity to neutralize any possible mine drainage, given the presence of acid-eating minerals such as the carbonates associated with the mineralization.

Recent expansion of artisanal gold mining along the Bandama River (Côte d’Ivoire)

• Artisanal and small-scale gold mining is a serious threat to the environment. • In Ivory Côte d’Ivoire, this activity has developed very quickly recently. • The lack of geographical information is an obstacle to the regulation. • The monitoring of artisanal mining from space can help governements. Recent development of small-scale gold mining activities in Côte d’Ivoire is a serious threat to the environment because of deforestation, soil scrapping, pit mining, over-use of water resources and pollution of surface and ground waters by mercury, cyanides, and acids. The challenge for the governance of this activity is to resolve the tension between the desired development of a small-scale mining activity, which may benefit the local and national economy, and the impacts of this activity on the environment. The regulation of the exploration and exploitation of mining sites and the promotion of best practices was part of the National program for the rationalization of gold-panning in Côte d’Ivoire. The capacity of the government to monitor the expansion of numerous mining sites disseminated all over the country is one of the key aspects for successful implementation of these policies. This study explores the potential value of computer-assisted mapping of artisanal mining sites based on Sentinel-2 imagery. The detection method, using artificial intelligence and training data sets generated during field campaigns, was inspired from a previous experience in Senegal. It was applied to a region of about 600 km 2 in Central Côte d’Ivoire. Annual maps of areas affected by the mining activities were produced for the period 2018 – 2021. The areas affected by artisanal mining activities expanded from 3.39 km 2 to 8.80 km 2 in December 2021, corresponding to an average growth rate of 0.24 km 2 /month. The temporal and spatial resolution of the Sentinel satellite imagery proved to be useful to map and quantify the expansion rate of artisanal mining sites in Côte d’Ivoire. Recommendations are made for the integration of these tools into plans for the development of small-scale mining activities in Côte d’Ivoire that would be more respectful of the environment and societies.

Environmental Impact Assessment of Mining Activities Around Rimin-Zayam, Toro LGA, Bauchi State

Mining environment is known for a high level of heavy metals due to the activities which cause adverse alteration of the ecological system. This research study the partitioning of heavy metals in artisanal mining sites in RiminZayan, Toro Local Government Area Bauchi state, Nigeria. The concentration of heavy metals like lead, Cadmium, Iron, Zinc, Cobalt (Co), Copper , Chromium, Manganes and Nickel, were determined using the sequential extraction method recommended by Community Bureau of Reference (BCR) and physic-chemical properties such as the pH, cation exchange capacity, total organic carbon, total organic matter, electrical conductivity and soil particle size. The result show that the soil in the area has a clayey texture with the percentage of clay, slit and sand ranging from 9.29–27.10, 6.31–13.41 and 59.32–84.39 %, respectively. The pH levels of the soil ranged from 6.04 to 6.45 indicating that the soil in thee study is slightly acidic in nature. The observed electrical conductivity (EC) obtained in this study for the samples of soil sediments taken from around the mining site were 26.76, 31,30 and 42.66 µs/cm respectively. The percentages of organic matter of the soil in the same location are 0.423, 0.061 and 0.452 %. Cation exchange capacity (CEC) of the soil in the same vanity were respectively found to be 4.003, 7.385 and 3.994 cmol/kg. The metals were fractionated into six fractions and determined using Atomic Absorption Spectrophotometric techniques (AAS). The results of the soil analysed indicated that there was high abundance of heavy metals such as cadmium, chromium, copper, iron, lead, nickel, and zinc in the residual fraction, pointing to their lithogenic origins, and therefore primarily inherited from the parent material. Cobalt and manganese are bound to other fractions (exchangeable, carbonate, manganese oxide, iron-manganes oxide, organic matter-sulphide, and residual metals which shows their anthropogenic origin. The ratio of bioavailability factor (BF) ranged from 27.47 to 89.66, Contamination factor showed values ranging from 0.001 to 16.299 which suggests that some soils were not contaminated while some were moderately contaminated metals investigated. The degree of contamination (DC) showed that the highest recorded were from non -mining area (19.517) while active mining sites and abandoned mining sites values are: 5.985 and 3.843, respectively. This trend could be owing to the bioavailability and mobility of the metals from the mining sites to non-mining locations. The data generated were subjected to one-way ANOVA. The least significant difference test (p ≤ 0.05).

Mining methods exert differential effects on species recruitment at artisanal small-scale mining sites in Ghana

Artisanal small-scale mining (ASM) is one of the essential rural non-agricultural livelihood activities in Ghana. However, basic and rudimentary practices and tools associated with ASM activities lead to vegetation and soil destruction. Given the limitation of state-sponsored reclamation of abandoned ASM sites, the role of natural recovery in abandoned mine sites is deemed a viable option, as it lowers financial obligations, promotes pioneer species and improves local ecology. The residual impacts of different ASM methods (alluvial or chamfi) and their implications for reclamation are less explored. Using a randomised sampling approach, one hundred and eight (108) plots representing 54 abandoned mined (27 alluvial and 27 chamfi) and 54 unmined areas (control plots) were demarcated for seedling and sapling assessments. A total of 6,157 seedlings belonging to 133 species and 4,536 saplings belonging to 42 species were recorded. Pielou's evenness and Shannon indices showed that both seedlings and saplings were equitably distributed between mined-out sites and their controls for both methods but showed evidence of environmental variability. This variability was more conspicuous in chamfi mined-out sites, confirming some degradation impacts. Chromolaena odorata (L.) and Mimosa pudica L. were the dominant seedlings recorded, while Hymenostegia afzelii (Oliv.) Harms and Musanga cecropioides M. Smithii R. Br. dominated the saplings. The alluvial method exerted a far greater effect on stand features such as basal area and stand density for saplings owing to its greater soil damage. Assisted restoration measures directed at abandoned mined sites can facilitate ecosystem recovery to a trajectory reminiscent of that of nearby undisturbed forests.

Role of climate and geography in arsenic mobility and risk at an artisanal mining site in an urbanized semi-arid environment

Ultra-enriched arsenic (As) concentrations >30% occur at an abandoned artisanal mine in an urban park in San Diego, California, presenting a complex risk to the public. This study uses geochemistry in consideration with climate and geography to evaluate As transport away from the mine. Sediment As concentrations reach 2320 mg/kg (483 times background crustal concentrations; n = 73) along drainage pathways and sequential extraction experiments indicate As overwhelmingly partitions into the least mobile phase (mean 83% As in residual fraction; n = 30); there is little redistribution of As from primary minerals into secondary or dissolved phases – a potentially positive outcome for managing the risk - despite the sediments being exposed to a century of weathering. Dissolved As transport does occur, with intermittent rain events producing As up to 272 μg/L in runoff. Both sediment and water As decrease to background concentrations within 1,000 m of the mines, influenced by the encroaching urbanization, and the semi-arid climate which limits weathering and transport. Similar patterns of As migration downgradient of abandoned mines occur at other mining sites in arid and semi-arid regions; however, off-site As transport at other sites extends far greater distances. This study indicates that a combination of geochemistry, geomorphology, climate, and urbanization can work together to retard the surface transport of As from artisanal and un-remediated mine sites; and helps inform environmental management at this site and others like it.

Artisanal Mining Practice and Physical Impacts on the Environment in the Ity-Floleu Gold Region, Côte d'Ivoire

This paper describes artisanal gold mining practices and environmental impacts around the Ity-Floleu gold mine, in western Côte d'Ivoire. Interviews and field observations as well as measurements of turbidity and water flow velocity in the section of the river (Cavally) watering the study area, made it possible to identify 13 artisanal mining sites, housing 247 artisans, operating in groups made up mainly of 5 to 10 people. The activity is dominated by local populations from the villages of Ity and Floleu and the surrounding communities. Gold mined comes from alluvial and vein ores, with a predominance of alluvial ore, extracted in the sediments of the bed and the banks of the river and in the soils, inside forests. In the bed of the river, sediments are dredged using machines placed on boats, from where they are washed in mats and then dumped into the watercourse. On the other hand, on the banks of the river and in the forests, the material used consists of picks, dabas, mats, and shovels. In all cases, gold is recovered as a concentrate of gold powder. As regards vein ores, they are also extracted along with the soils of cultivable land, but in the form of blocks of stone which are crushed and washed. The gold is then recovered using mercury, followed by cyanidation. The techniques used lead to the silting up and the fall of the banks of the river, reduction of agricultural land, and the degradation of the environment by the tailings. The Cavally River appears to be strongly impacted in the midstream part of the Ity-Floleu axis, marked by a decrease in the bed and the river flow velocity (0.19 m/s) and higher turbidity (255.3 NTU). More effective policies are urgently needed to restore degraded ecosystems, both aquatic and terrestrial.

Evaluation and Speciation of Heavy Metals Contamination of Selected Artisanal Mining Sites in Mangu Local Government Area of Plateau State, Nigeria

Artisanal (illegal) mining has been reported to have environmental and health effects on the surrounding communities due to heavy metals pollution. The determination of total heavy metal concentration does not reflect the toxicity and bioavailability of the metals. Toxicity and bioavailability of the metals can be achieved by determining the form in which the metal exist in the environment (speciation). This present work evaluated the heavy metals’ {cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb), zinc (Zn) &nickel (Ni)} contamination and the form in which they exist at some mining sites in Mangu LGC, Plateau state, Nigeria. Aqua regia ((HCl + HNO3, 3:1 v/v) was used for total metal concentration while sequential extraction method was used to orderly determine the speciation of the heavy metals. The level of the heavy metals in the digested solutions were determined using Buck Scientific model 210VGP Atomic Absorption Spectrophotometer (AAS). The results divulged that the concentrations of the heavy metals were within the FEPA and WHO recommended permissible limit except Cd and Ni. The values of the metals at Mangu Halle mining site followed the sequence: Mn > Zn > Ni > Pb > Cu > Cd whereas the sequence at Alogwom was Mn > Zn > Pb > Ni > Cu > Cd. The results of the speciation indicated that all metals were bound to the five fractions with the residual fraction dominating except Cd which was bound mostly to the soluble and exchangeable fractions. It could be concluded that the presence of these heavy metals in the mobile fractions, indicate that they could be easily released to the environment from soil. Thus, they are also likely to cause toxicity in the environment. Proper monitoring of the mining activities in the communities was recommended.