Acid Mine Drainage Sources Research Articles

Micron-scale distribution controls metal(loid) release during simulated weathering of a Pennsylvanian coal shale

Coal mine spoil is a long-lasting legacy of historic coal mining operations that continues to impact water quality across Appalachia. Metal(loid) release from abandoned coal mine spoil, which can be a significant source of acid mine drainage (AMD), is dependent on speciation and distribution within the parent coal shale. This work aimed to determine how the micron- and sub-micron scale mineralogy, morphology, and texture of metal(loid)-bearing phases in a coal-shale control the rate and release of metal(loid)s during subsequent weathering through two primary objectives: (1) determine the microscale speciation and distribution of Fe and other metal(loid)s in a parent coal shale, and (2) determine the amount of metal(loid)s released during simulated weathering of shale physically crushed into silt- to sand-sized particles. This work was accomplished through a combination of electron microscopy and synchrotron-based X-ray microprobe analyses. This suite of techniques also provides insight into the geochemical history of the coal shale that could not be determined by bulk techniques. Trace elements were associated with either Fe-sulfides or with other phases that included metal(loid)-sulfides, aluminosilicates, and organic matter. Three distinct pools of Fe-sulfides were present: (i) larger mm-scale grains, with minimal internal fractures; (ii) μm- to mm-scale aggregates of μm-scale crystals forming secondary coatings on the larger mm-scale grains, and (iii) μm- to mm-scale aggregates forming framboidal grains. Fe-sulfide mineralogy was dominated by pyrite with minor contributions of marcasite and a S(-II)-bearing phase. Larger pyrite grains and their secondary coatings contained homogeneous distributions of Fe and Mn as well as other trace metal(loids) including V, Ti, Cr, As, Se, Cu, and Zn. The fine-grained pyrite aggregates were strongly enriched in As and Se and contained discrete Cu- and Zn-bearing particles. Clays and organic matter surrounding the sulfide minerals were identified by micro-XRD and FT-IR spectroscopy. Simulated batch weathering of the physically crushed shale resulted in metal(loid) release that varied as function of size fraction and time. Metal(loid) release increased with decreasing particle size from sand-sized to silt-sized fractions. Although small amounts of Fe were released into solution after two days, the bulk of Fe release occurred after 10 days and continued for six months, after which Fe was gradually removed from solution. The weathering trends for Mn, Cu, Zn, and Ni were similar to Fe. In contrast, As and Se were characterized by rapid release into solution followed by removal prior to 10 days. These results indicate that micrometer-scale metal(loid) distribution within Fe sulfides controlled metal(loid) release into solution during simulated weathering of a coal shale. Specifically, elements concentrated in mineral coatings (As, Se) were rapidly mobilized in a short-lived pulse whereas elements associated with the larger grains (Fe, Mn, Cu, Zn, and Ni) exhibited a delayed but prolonged release into solution. The non-concomitant contaminant release indicates that an understanding of the textural relationships in the source material is required to understand weathering trends. This work highlights the importance of non-point sources of AMD, and addressing these sources is a critical step in improving water quality in the region.

Mitigasi Dan Arahan Pengelolaan Air Asam Tambang Melalui Hutan Rawa Buatan Di Lahan Pasca Tambang

The application of remote sensing using Unmanned Aerial Vehicle (UAV) technology to identify distribution of Acid Mine Drainage (AMD) as part of mitigation process has been done in PT. Jorong Barutama Greston. UAV imagery was interpreted visually to produce land cover map. Bare land area from land cover map is used as the boundary of the analysis area for the mitigation of AMD source. Color of soil in UAV images is used as training area for supervised classification to differentiate different pH. The result shows distribution of soil with pH between 2-3 is 1.2 ha, pH 3-4 is 4.5 ha, and pH 4-5 is 9 ha. This analysis can show that mapping results using aerial photo is effective to identify pH of soil in bare land as a source of acid to water in void and it used as input for revegetation and swamp forest planning as bio-phytoremediation efforts. Swamp forest as a wetland is one recomendation for sustainable water management on mine to increase pH and reduce heavy metal content. The success of constructed swamp forest as passive treatment for bio-phytoremediation is determined by the selection of plant species, site location, design and construction of swamp forest and maintenance. Typha latifolia, Salvinia sp., Fimbristylis globulosa, Chrysopogon zizanioides, Melaleuca leucadendra, Melaleuca cajuputi, Nauclea subdita and Nauclea orientalis L. are recom-mended as local selected plants for phytoremediation. Obtained six variables that significantly affected to determination of site location for constructed swamp forest are elevation (T), slope (S), land cover (L), cathment area (C), distance from channel (K) and distance from the monitoring pool (P). The model X = 0.2T + 0.2S + 0.1L + 0.15C + 0.3K + 0.05P applied to find very suit-able area with α = 0.05 and the R-square (R2) value 93.4%.

Acid mine drainage sources and hydrogeochemistry at the Yatani mine, Yamagata, Japan: A geochemical and isotopic study

This paper describes the geochemistry of groundwater and its flow system in the closed Yatani mine in southern Yamagata Prefecture, Japan. The mine is located in a sulfide deposit containing pyrite and has been generating acid mine drainage (AMD). The study was intended to elucidate the formation of AMD and its flow patterns using geological, hydrological, geochemical, and isotopic techniques. The results indicate that AMD is formed by the interaction of groundwater with sulfide minerals, sand slime, and tailings back-filled into excavated mine areas. Groundwater recharge areas were identified on the mountain slope at an elevation of ~900 m. The formation of AMD in the drifts and shaft was more extensive than that in the deeper drainage levels. Principal component analysis was applied to the hydrogeochemical data to identify the causes of AMD formation. The first, second, and third principal components reveal that the increased ion concentrations in mine drainage are a result of water–mineral reactions in excavated mine areas, the contribution of groundwater in deep reductive environments, and isotopic fractionation during precipitation, respectively. A promising method of reducing AMD formation is to prevent contact between dissolved oxygen and sulfide minerals by increasing the drainage level or by filling the shallow underground excavated area with cementitious materials.

Supergene alteration, environmental impact and laboratory scale acid water treatment of Cyprus-type ore deposits: case study of Mathiatis and Sha abandoned mines

Waste-rock dumps and the water quality of pit-lakes formed at abandoned mines of pyrite-rich ore deposits are of considerable environmental concern around the world. The Mathiatis and Sha mines provide typical examples of abandoned mines where Cyprus-type Cu-pyrite ore was exploited. Supergene alteration of the sulphide ore and the mine waste leads to the formation of efflorescence and generation of acid mine drainage filling the pit-lakes. Sulphate concentrations range from 4600 to 4850 mg/l and from 35 900 to 38 500 mg/l for the Mathiatis and Sha mines, respectively. Concentrations of heavy metals exceed the established regulatory limits in water. A preliminary assessment of the mine waste at the Mathiatis mine indicated that it cannot be characterized as inert material according to current European legislation, posing an environmental threat as a source of acid mine drainage (AMD). The identified Mg, Ca and Fe(II)- Fe(III) efflorescence mineral phases retain temporarily trace metals near the mine waste and the open pit-lake shore. Neutralization experiments on the acidic waters of the epilimnion indicated local limestone is not sufficient for full remediation. However, it could be used as a low-cost pretreatment method for AMD. The study expands the international database of AMD affected areas and provides the basis for future remediation efforts. Supplementary material: Detection limits and reference material analyses is available at https://doi.org/10.6084/m9.figshare.c.4383254

Evaluation and microanalytical study of ZVI/scoria zeolite mixtures for treating acid mine drainage using reactive barriers – Removal mechanisms

Batch and column experiments were performed to evaluate contaminant removal from acid mine drainage (AMD) using volcanic scoria zeolite (VS) with or without zero-valent iron (ZVI). Two sources of AMD were used, comprising WZ from a gold mine and TDB from a coal mine. Both the WZ and TDB were acidic mine water with pH values of 2.43 and 2.93, respectively. It was found that VS was effective in removing heavy metals from AMD despite attaining a relatively lower maximum pH of 5.5, compared to the pH values of 7.0–8.5 attained using ZVI. The reactive media VS, ZVI, and 50:50 ZVI-VS all achieved effective removal of Al, Fe, Zn metals. The mixture 50:50 ZVI-VS gave the best contaminant removal performance, relative to the other reactive media used in the investigation.Hematite and Goethite minerals were formed in ZVI upon its exposure to AMD during the mine water treatment. The VS that was exposed to AMD showed enhancement of Diopside and Augite along with the formation of two new phases comprising Forsterite and Ferroan. Geochemical changes and microanalytical investigations altogether showed pH-dependent chemical precipitation to be the main mechanism of heavy metal removal by ZVI, while adsorption and cation exchange processes were found to be responsible for pollutant removal by VS.

Geochemical behaviour of rare earth elements (REE) along a river reach receiving inputs of acid mine drainage

Total and dissolved rare earth elements (REE) were studied in a river reach affected by several inputs of acid mine drainage. The first four acidic discharges were of lesser importance compared to the last (Agrio River, coming from the Río Tinto mines), which transported high loads of Fe and Al (2.1 and 4.2 ton/day, respectively) together with REE (16.4 kg/day) and other trace elements. In the acid mine drainage (AMD) sources, practically all the REE were dissolved and the North American Shale Composite (NASC)-normalized patterns showed an enrichment in medium REE, although some differences exist between the patterns of each source. The pH values in the river reach upstream of the confluence with the Agrio River ranged between 8.01 and 7.03, and most of the Fe and Al from the AMD sources precipitated. Downstream of this acidic discharge, the pH decreased to 2.98. Upstream of the first AMD input, the dissolved and total concentrations of ΣREE were very low (<0.6 μg/L). In the river reach affected by AMD that maintains pH values >7, concentrations of ΣREE increased (up to 25 μg/L), mainly transported by the particulate phase. In the reach downstream of the Agrio River with acidic conditions, REE behaved conservatively. The REE NASC-normalized patterns of the river samples resemble that of the AMD sources, although an enrichment of heavy REE in the dissolved phase is observed linked to complexation by carbonates. Cerium and particularly La also show higher dissolved percentages, similar to HREE, which must be due to the lower affinity of these elements to be sorbed onto Fe oxyhydroxides. Variations in Ce and Eu anomalies are observed along the river reach as a consequence of the different AMD inputs. However, the values of the Ce anomaly are higher in total samples than in dissolved samples. Speciation results indicate that these differences are not caused by differences in oxidation states but by slight differences in the hydrogeochemical behaviour of Ce with respect to La and Nd.

Influence of Acid Mine Drainage, and Its Remediation, on Lakewater Quality and Benthic Invertebrate Communities

The abandoned Aldermac Mine in Quebec, Canada, has been a source of acid mine drainage to Lake Arnoux since 1946. Restoration of the site was undertaken in 2008 and completed in 2010. We compared lakewater chemistry and benthic invertebrate communities in the spring of 2010, prior to complete restoration, and in spring 2011, when acid mine drainage was no longer entering the lake. Between these years, lakewater pH increased by about one unit and the concentrations of many trace metals declined substantially. In 2010, benthic taxonomic richness increased significantly with distance from the source of contamination, whereas after restoration, there was no longer a clear trend. Communities in highly contaminated stations tended to be dominated by burrowing taxa such as larvae of Chironomus (Chironomidae) and Oligochaeta, whereas less contaminated stations had taxonomic and functional communities that were more diverse. In the year following recovery, some new taxa appeared (Trichoptera, Odonata, and the Ceratopogonidae Bezzia), whereas the populations of an acid-tolerant Chironomus species declined. However, only larger individuals exhibited a significant response to pH and metal contamination.

Combined hydrochemical, isotopic, and multivariate statistics techniques to assess the effects of discharges from a uranium mine on water quality in neighboring streams

The Caldas Uranium Mine (CUM), located on the Pocos de Caldas Plateau in the southeastern region of Brazil, is presently undergoing a decommissioning process. The aim of the present investigation is to identify and characterize the effects of acid mine drainage (AMD) originating from the CUM on surface water quality. To achieve these aims, sampling stations were located at two AMD sources: the retention pond at the foot of waste rock pile#4 (WRP#4) and the settling pond that receives effluents from the tailings dam (TD). Ten additional sampling stations were located along watercourses in the vicinity, both downstream and upstream of the mine. Sampling was performed during the rainy and dry seasons in 2010 and 2011. The water analysis detected significant changes in pH, electrical conductivity, F−, Cd, U, Zn, Al, Mn, As, Ca, SO4 2−, Pb, 238U, 226Ra, 210Pb, 232Th, 228Ra, and Mo in waters downstream of both pond discharge sites. It was demonstrated that the disequilibrium between 226Ra and 238U can be used to trace the extent of AMD impacts in nearby streams. Variations in 18O and 2H enabled the flow of mining-impacted water to be traced from the ponds to nearby streams. Multivariate analysis yielded a three-factor model: Factor 1 was interpreted as being associated with AMD (from WRP#4) and Factor 2 with a Ca–Mo relationship associated with the chemical constitution of the ore and with the treatment of tailings wastes in the area (from TD); Factor 3 was interpreted as being associated with the natural influence of geogenic processes on water quality in the area. The results of this study provide a scientific basis for recommending appropriate remedial actions during mine decommissioning.

GIS-based groundwater vulnerability modelling: A case study of the Witbank, Ermelo and Highveld Coalfields in South Africa

In the last 20 years, the popular mineral systems approach has been used successfully for the exploration of various mineral commodities at various scales owing to its scientific soundness, cost effectiveness and simplicity in mapping the critical processes required for the formation of deposits. In the present study this approach was modified for the assessment of groundwater vulnerability. In terms of the modified approach, water drives the pollution migration processes, with various analogies having been derived from the mineral systems approach. The modified approach is illustrated here by the discussion of a case study of acid mine drainage (AMD) pollution in the Witbank, Ermelo and Highveld coalfields of the Mpumalanga and KwaZulu-Natal Provinces in South Africa.Many AMD cases have been reported in these provinces in recent years and are a cause of concern for local municipalities, mining and environmental agencies. In the Witbank, Ermelo and Highveld coalfields, several areas have been mined out while mining has not yet started in others, hence the need to identify groundwater regions prone to AMD pollution in order to avoid further impacts on the groundwater resources. A knowledge-based fuzzy expert system was built using vulnerability factors (energy sources, ligands sources, pollutant sources, transportation pathways and traps) to generate a groundwater vulnerability model of the coalfields. Highly vulnerable areas were identified in Witbank coalfield and the eastern part of the Ermelo coalfield which are characterised by the presence of AMD sources, good subsurface transport coupled with poor AMD pollution trapping properties. The results from the analysis indicate significant correlations between model values and both groundwater sulphate concentrations as well as pH. This shows that the proposed approach can indeed be used as an alternative to traditional methods of groundwater vulnerability assessment. The methodology only considers the AMD pollution attenuation and migration at a regional scale and does not account for local-scale sources of pollution and attenuation. Further research to refine the approach may include the incorporation of groundwater flow direction, rock-pollution reaction time, and temporal datasets for the future prediction of groundwater vulnerability. The approach may be applied to other coalfields to assess its robustness to changing hydrogeological conditions.

Prediction of Acid Mine Drainage (AMD) and Metal Release Sources at the Küre Copper Mine Site, Kastamonu, NW Turkey

Waste and lithological rocks were subjected to aqueous leaching, acid base accounting (ABA), and net acid generation (NAG) tests, and detailed mineralogical investigations were conducted to predict acid mine drainage (AMD) formation at Turkey’s largest historical copper deposits. The field water chemistry from springs and seeps on the mine site were compared with the static and long term aqueous leaching test results. During the ABA, NAG and long term paste pH tests, ore rich and ore bearing wastes showed a paste pH <4, implying their acid generating nature. The relationship between net neutralization potential and acid producing potential revealed that waste rocks with a low sulfur content were generally low potential sources of AMD. Consistent with the static test results, aqueous leaching tests revealed that greater concentrations of Fe, Cu, Zn, Ni, Pb, Cd, Co and As were released from the wastes rich in pyrite. The test methods all generally agreed that the ore-rich wastes (O, P1C, P1D) were the main sources of AMD and metal contamination in the district.

Exploration of Diffuse and Discrete Sources of Acid Mine Drainage to a Headwater Mountain Stream in Colorado, USA

We investigated the impact of acid mine drainage (AMD) contamination from the Minnesota Mine, an inactive gold and silver mine, on Lion Creek, a headwater mountain stream near Empire, Colorado. The objective was to map the sources of AMD contamination, including discrete sources visible at the surface and diffuse inputs that were not readily apparent. This was achieved using geochemical sampling, in-stream and in-seep fluid electrical conductivity (EC) logging, and electrical resistivity imaging (ERI) of the subsurface. The low pH of the AMD-impacted water correlated to high fluid EC values that served as a target for the ERI. From ERI, we identified two likely sources of diffuse contamination entering the stream: (1) the subsurface extent of two seepage faces visible on the surface, and (2) rainfall runoff washing salts deposited on the streambank and in a tailings pile on the east bank of Lion Creek. Additionally, rainfall leaching through the tailings pile is a potential diffuse source of contamination if the subsurface beneath the tailings pile is hydraulically connected with the stream. In-stream fluid EC was lowest when stream discharge was highest in early summer and then increased throughout the summer as stream discharge decreased, indicating that the concentration of dissolved solids in the stream is largely controlled by mixing of groundwater and snowmelt. Total dissolved solids (TDS) load is greatest in early summer and displays a large diel signal. Identification of diffuse sources and variability in TDS load through time should allow for more targeted remediation options.

Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand

&#x0D; &#x0D; &#x0D; Wetlands are well known to be efficient at sequestering pollutants from contaminated water. We investigated metal accumulation in the peats of the Klip River, a natural wetland that has received contaminated water from gold mining operations in Johannesburg for over 130 years. Previous work conducted in the downstream portion identified the wetland as an important system for sequestering metals. We focused on the upstream section of the wetland, more proximal to the source of acid mine drainage, to provide a better understanding of the pollutant sources and the role of the wetland in pollutant attenuation. Geochemical and mineralogical analyses of peat cores revealed considerable metal enrichments in the peat ash, particularly in Co, Ni, Zn, Pb, Cu and U. Metal concentrations are typically between 4 to 8 times higher than those previously reported for the downstream, more distal portion of the wetland. The distribution of metal accumulation within the peat profiles suggests that contamination arises from a combination of sources and processes. Elevated concentrations in the shallow peat are attributed to the input of contaminated surface water via tributaries that drain the Central Rand Goldfield, whereas enrichments in the deeper peat suggest significant sub-surface inflow of contaminated water through the underlying dolomitic rocks. Metal immobilisation occurs through a combination of mechanisms, which include the precipitation of gypsum, metal sulfides, Fe-Mn oxyhydroxides and phosphates. Our study highlights the environmental and economic importance of natural wetland systems which have the ability to accumulate large quantities of metals and thus remediate polluted waters.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Significance: &#x0D; &#x0D; &#x0D; &#x0D; Considerable levels of metal accumulation are observed within the Klip River wetland peats.&#x0D; The wetland is effective in remediating highly polluted water emanating from the Witwatersrand Basin.&#x0D; The Klip River system is important for the region’s future water supply.&#x0D; &#x0D; &#x0D; &#x0D;

Temporal Variations of REE in Several AMD Sources of the Odiel River (SW Spain)

Waters affected by acid mine drainage (AMD) can contain high concentrations of rare earth elements (REE) which have a great interest not only by its application as tracers in hydrogeochemical processes but also as a potential economic resource. The Iberian Pyrite Belt (IPB) is rich in sulfide deposits which have been exploited intensively since ancient times, generating numerous AMD discharges. This work studies the REE content in five different AMD sources located in the upper reach of the Odiel River (SW Spain). The concentration of REE in these sources ranged from 113 to 7208 ppb. Differences in NASC-normalized REE patterns were observed among AMD sources that remained constant along the year despite the variability in REE concentrations, being lower during the rainy season due to dilution processes.

Characterization of Main AMD Inputs to the Odiel River Upper Reach (SW Spain)

The Iberian Pyrite Belt (IPB) is rich in sulfide deposits which have been intensively exploited, generating a huge problem of contamination of the Odiel River by acid mine drainage (AMD). At its source is a clean river, but along a 7 km-long reach receives five discharges of acid mine waters: Concepción, San Platón, Esperanza, Poderosa and the Agrio River, which drains the AMD contaminated water from the Río Tinto mines. The flows and hydrogeochemical characteristics of these AMD sources have been studied. The Agrio River is the main contributor of acidity, sulfate and metals to the Odiel River due to its high flows and pollutant concentrations. San Platón and Poderosa mines have high sulfate and metal concentrations although both sources are characterized by low or moderate flows while Concepción has the lowest concentrations but higher flows. The composition of AMD sources seem to be controlled by the mineralogy of the deposits and by geochemical processes. Strong seasonal variations are observed for some AMD sources while others are more constant throughout the year.

KAJIAN PENANGGULANGAN AIR ASAM TAMBANG PADA SALAH SATU PERUSAHAAN PEMEGANG IJIN USAHA PERTAMBANGAN DI DESA LEMO, KABUPATEN BARITO UTARA, KALIMANTAN TENGAH

This study aims to know the factors that cause the formation of Acid Mine Water, to analyze the methods of prevention of acid mine drainage has been running effectively, to analyze how to prevent the formation of acid mine water at the research area. This research was conducted atLemovillage,North Barito Regency. These results indicate the analysis of water quality in the company with an indication acidic low pH values and high metal values. It is supported by soil pH test results showed low pH, especially on the layer in direct contact or close to coal. Sources of acid mine drainage at the company are from the oxidation of water and oxygen on the wall of rock at pit, water from the dumping area, water flowing from the temporary stockpile into the settling pond 2. From these, we can conclude the results. Recommendations prevention of acid mine drainage can be done by moving the location of the temporary stockpile in accordance with, more effective functioning of sump, controlling the movement of acidic water that has formed, accommodate and neutralize the acidic water that has formed, forming a layer of dry cover, separating the flow of water is not acidic and acidic

Sources, distributions of fluoride in waters and its influencing factors from an endemic fluorosis region in central Guizhou, China

The use of high fluoride-content coal caused the severe coal-burning endemic fluorosis in Zhijin County, Guizhou Province, China. The long-term mine exploitation in this region is as an important source of acid mine drainage (AMD) and leads to the release of potential fluoride (F−) into the surrounding waters. Aiming to investigate the source, hydrogeochemical characteristics and influencing factors of fluoride in waters of this area, a hydrogeological and geochemical research has been conducted in this study. Samples of various types of waters were collected and analyzed for major cations, major anions and TFe, Al; selected coal and gangue samples were analyzed for fluoride contents. The F− concentration in AMD or AMD-affected waters ranged from 0.27 to 4.94 mg/L, and F− was mainly enriched in Na–SO4 and Mg–SO4 waters, but a relatively low F− concentration was found in the Ca–SO4 water. The F− concentration in the Ca–HCO3 water without being affected by AMD ranged from 0.01 to 0.20 mg/L. The elevated F− contents were found in the AMD, which is mainly influenced by the local coal mining activities, and it is resulted from the dissolution of fluoride-bearing minerals in coal-bearing clastic rocks, as well as the low pH values, high Al and Fe concentrations, high total dissolved solids and high Al/F ratio of the AMD. In addition, the dissolution/precipitation of carbonate rocks and special hydrogeological conditions determined the F− concentration in surface water. Meanwhile, the climate is also an influencing factor that cannot be ignored to affect the F− concentrations of surface water and groundwater.

Relationships between sources of acid mine drainage and the hydrochemistry of acid effluents during rainy season in the Iberian Pyrite Belt.

In the Iberian Pyrite Belt (IPB), southwest Spain, a prolonged and intense mining activity of more than 4,500 years has resulted in almost a hundred mines scattered through the region. After years of inactivity, these mines are still causing high levels of hydrochemical degradation in the fluvial network. This situation represents a unique scenario in the world, taking into consideration its magnitude and intensity of the contamination processes. In order to obtain a benchmark regarding the degree of acid mine drainage (AMD) pollution in the aquatic environment, the relationship between the areas occupied by the sulfide mines and the characteristics of the respective effluents after rainfall was analysed. The methodology developed, which includes the design of a sampling network, analytical treatment and cluster analysis, is a useful tool for diagnosing the contamination level by AMD in an entire metallogenic province, at the scale of each mining group. The results presented the relationship between sulfate, total dissolved solids and electrical conductivity, as well as other parameters that are typically associated with AMD and the major elements that compose the polymetallic sulfides of IPB. This analysis also indicates the low level of proximity between the affectation area and the other variables.

Assessment of the acid mine drainage potential of waste rocks at the Ak-Sug porphyry Cu–Mo deposit

This investigation was conducted using waste rock materials from the Ak-Sug porphyry Cu–Mo deposit, which is located in the northeastern region of the Tuva Republic in Russia. To predict the formation of acid mine drainage, the waste rocks were investigated using X-ray fluorescence with synchrotron radiation spectroscopy (XRF-SR), X-ray diffraction analysis (XRD), microscopy, and aqueous leaching and intensive oxidation experiments. In addition, the sulfide and carbonate contents were determined to calculate the net acid potential. The waste rock materials were generally low potential sources of acid mine drainage. Only 26% of the rock samples produced acidic effluent following long-term storage. In the results that were obtained from the complete oxidation of the waste rocks, the drainage solutions that were generated had elemental concentrations that exceeded the following MPC (Maximum Permissible Concentrations): Fe — 560 times; Cu — 43 times; Mn — 23 times; Mo — 20 times; As — 50 times; Cd — 19 times; Sb — 17 times; Se — 7.5 times; and Co — 4.5 times. Arsenic was of particular concern in the waste rocks due to its high concentrations, with more than 50% of the samples containing arsenic at concentrations of more than 10g/t and with a maximum concentration of 450g/t. Arsenic can leach rapidly in neutral and sub-alkaline solutions (which were dominant in the aqueous extracts of the investigated rocks).The change of the element species in solutions was shown by the WATEQ4F calculations. Occurrences of sulfate complexes of the elements resulted in higher concentration of Al, Fe and Mn in the solution. The most environmentally hazardous species Me(H2O)62+ of copper, zinc, and cadmium begins predominate in drainage solutions during a long storage of the sulfide-containing wastes.WATEQ4F equilibrium calculations indicated that in acidic solutions the partial dissolution of the hydroxides and oxides of Al, Fe, and Mn, and the substantial desorption of the potentially toxic elements from their hydrated surface and crystal lattice will occur.These results will be used for modeling and designing waste dumps, which could prevent acid production.

Endoparasite Community Differences in Sunfish (Lepomis spp.) Above and Below Coal Mine Effluent in Southern Illinois.

Parasite assemblages acquired through trophic interactions in fish hosts are increasingly cited as a means to determine pollution effects on water quality and food web structure. We examined gastrointestinal parasite community changes above and below coal mine input from 597 individuals representing 3 species of sunfish: green sunfish ( Lepomis cyanellus ), bluegill ( L. macrochirus ), and longear sunfish ( L. megalotis ). Hosts were collected from 6 sites in or near the south fork of the Saline River Basin in southern Illinois in the spring and fall of 2006. Three sites received no known effluent from coal mines. An additional 3 sites received effluent termed acid mine drainage (AMD). We recovered 1,064 parasites from 12 genera. The parasite community in sunfish collected downstream nearest to the source of AMD was significantly different from 3 upstream sites. In addition, 2 sites farther downstream receiving AMD were different from 2 of 3 reference sites. However, there was also considerable variability in parasite assemblages between sites grouped as above or below coal mine effluent. Several parasite species responded to changes in water quality. Spinitectus sp. (Nematoda), which uses sensitive mayfly hosts to complete its life cycle, was less abundant at sites downstream of coal mine effluent in both green sunfish and bluegill. In contrast, 2 acanthocephalans ( Neoechinorhynchus sp. and Eocollis arcanus) and a nematode ( Spiroxys sp.) were found in green sunfish more frequently in areas downstream of AMD. This study further suggests metazoan parasites may be useful as indicators of water quality; however, variability among similar sites may limit their application. In addition, strong assemblage differences were found among the 3 sunfish species, suggesting variable habitat usage and potential resource partitioning among congeneric fish hosts in streams.

Humic acid decreases acute toxicity and ventilation frequency in eastern rainbowfish (Melanotaenia splendida splendida) exposed to acid mine drainage

Acid mine drainage (AMD) is a global problem leading to the acidification of freshwaters, as well as contamination by heavy metals. The ability of humic substances (HS) such as humic acid (HA) to decrease toxicity of heavy metals is widely known, whereas limited studies have examined the ability of HS to decrease toxicity linked with multiple stressors such as those associated with AMD. This study investigated the ability of HA to decrease acute toxicity defined as morbidity and ventilation frequency (measured via the time elapsed for ten operculum movements) in eastern rainbowfish (Melanotaenia splendida splendida) exposed to the multiple stressors of AMD-driven heavy metal concentrations, together with low pH. Water from the Mount Morgan open pit (a now closed gold and copper mine site), located at Mount Morgan, Central Queensland, Australia, was used as the AMD source. Fish were exposed to zero per cent (pH 7.3), two per cent (pH 6.7), three per cent (pH 5.7) and four per cent (pH 4.6) AMD in the presence of 0, 10 and 20mg/L Aldrich Humic Acid (AHA) over 96h. HA was shown to significantly decrease the acute toxicity of AMD and its adverse effects on ventilation frequency. These results are important in showing that HA can influence toxicity of metal mixtures and low pH, thus indicating a potential role for HA in decreasing toxicity of multiple environmental stressors more widely, and possible value as a rehabilitation aid.