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1.
The Impact of Phosphate Mine Tailings on the Bioaccumulation of Heavy Metals in Marine Fish and Crustaceans from the Coastal Zone of Togo 总被引:1,自引:0,他引:1
Abstract About 2.5 million t of sedimentary phosphorite mine tailings, highly enriched with Cd, Cr, Cu, Ni, Fe, F, and Zn, are dumped
annually in the coastal waters of Togo without any pre-treatment, causing serious pollution problems in the region. We conducted
bioaccumulation investigations on fish and crustaceans sampled from the polluted coastal zone. The highest concentrations
of metals in fish and crustacean were found close to the tailings outfall and the values decreased further away from the source
of pollution. Compared to the international reference norms for seafood given by the WHO, Cd is enriched 10 to 168 fold, Pb
20 to 107 fold, Cu up to 5 fold, Fe up to 15 fold, and F up to 3 fold. 相似文献
2.
Abstract Lakes develop when pits from open cut mines are left to fill with groundwater. In recent years, mining companies, mining communities,
and regulatory agencies have begun to consider potential beneficial end uses for mine lakes. Beneficial end uses are unlikely
to be without environmental impacts, however, and a proper consideration of the total benefit to the community should consider
them. This paper briefly reviews potential beneficial end uses and possible environmental impacts that might arise with them
for mine lakes in the Collie Basin, a coal mining region in Western Australia. We identified eight distinct, but not necessarily
incompatible, end uses from a search of the literature on mine lakes throughout the world: recreation and tourism, wildlife
conservation, aquaculture, irrigation, livestock water, potable water, industrial water, and chemical extraction. Recreation,
conservation, and possibly aquaculture use the mine lake directly, whereas the other end uses utilise extracted water. All
end uses have the potential to have environmental effects, with the most common being an actual or perceived impact on human
health and safety. A semi-quantitative risk assessment, using published literature sources, identified wildlife conservation
as the end use with the least environmental risk, and irrigation as the end use with the greatest environmental risk. Such
risks need to be balanced against economic and social benefits. There is an urgent need for a regulatory framework to address
mine lake options. 相似文献
3.
Abstract. Due to operational and regulatory practicalities, pit lakes will continue to be common legacies of mine lease relinquishments.
Unplanned or inappropriate management of these geographical features can lead to both short- and long-term liability to mining
companies, local communities, and the nearby environment during mining operations or after lease relinquishment. However,
the potential for pit lakes to provide benefit to companies, communities, and the environment is frequently unrecognised and
yet may be a vital contribution to the sustainability of the open-cut mining industry. Sustainable pit lake management aims
to minimise short and long term pit lake liabilities and maximise short and long term pit lake opportunities. Improved remediation
technologies are offering more avenues for pit lakes resource exploitation than ever before, at the same time mining companies,
local communities, and regulatory authorities are becoming more aware of the benefit these resources can offer. 相似文献
4.
K. Gnandi G. Tchangbedji K. Killi G. Baba A. I. Ouro Salim 《Mine Water and the Environment》2005,24(4):215-221
Abstract About 2.5 million t of sedimentary phosphorite mine tailings, highly enriched with trace metals such as Cd, Cr, Cu, Ni, and
Zn, are dumped annually in the coastal waters of Togo without any pre-treatment, causing serious pollution problems in the
region. We conducted laboratory jar tests of a coagulation-flocculation procedure with coagulants RM45U and AN945MPM to clarify
the sludge. The efficiency of the method depends particularly on two factors: the amount of coagulant and the solid concentration
of the sludge to be treated. Thus, with a mud concentration of 47.7 g/L, the average optimal amount of the two coagulants
was 25 mg/L. With both coagulants, water turbidity passed from 60 x 103 NTU to approximately 3 NTU after clarification with
the optimal amount of the two coagulants. RM45U reduced concentrations of Pb by 40%, Zn by 98.8%, Fe by 80.6%, and Cd by 32.8%.
AN945MPM reduced Pb by 20%, Zn by 98.5%, Fe by 48%, and Cd by 32.8%. 相似文献
5.
Abstract Closure of Pb-Zn mines in the Iglesias district (SW Sardinia, Italy) caused the cessation of pumping in 1997, and the consequent flooding of underground workings. Deep saline water mixed with the shallow groundwater as the water table rose, increasing salinity. Stratification caused the saline water at depth to settle over a period of three years. At the beginning of rebound, an increase in dissolved Zn, Cd, Pb, and Hg was observed under near-neutral pH conditions. Following peak concentrations, a marked decrease of Zn, Cd, and Hg, and to a lesser extend Pb, occurred. After 7 years of rebound, the concentrations of these metals are relatively low at most mine sites, although the levels are generally still higher than in unmined areas. Nowadays, the highest release of metals to the aquatic system occurs from the weathering of tailings and mine wastes. 相似文献
6.
Abstract. Leachate water quality from covered and uncovered unoxidised sulphide-rich tailings in six pilot-scale (5x5x3 m3) test cells was monitored during 2004 and 2005. The covers consisted of a layer of clayey till, sewage sludge, apatite or
Trisoplast (a commercial mixture of tailings, bentonite, and a polymer). All layers were protected by an unspecified till
except in one reference cell, where the tailings were left open. All leachate waters showed near-neutral pH as a result of
neutralization by calcite in the tailings and by Ca(OH)2 added prior to deposition. Average dissolved sulphur concentrations in the leachates were ≈ 600 mg L-1, except in the cell with sewage sludge (300 mg L-1). The source of sulphur was mainly pyrite oxidation, but residual sulphur probably remained from the enrichment process.
The near-neutral pH favoured precipitation of metal-(oxy)hydroxides with subsequent removal of trace elements such as Cd,
Cu and Pb (< 15 μg L-1) from the solutions. High concentrations of Co, Mn, Ni, and Zn were found in leachates from the apatite, Trisoplast, and
uncovered tailings cells. High As concentrations were found in the leachates in the sewage sludge and clayey till cells. The
lowest metal concentrations, redox potential, and highest pH were found in the sewage sludge cell. Decreased elemental metal
concentrations during 2004 suggest improved performance over time. 相似文献
7.
Abstract Closure of Pb-Zn mines in the Iglesiente district (SW Sardinia, Italy) caused the cessation of pumping in 1997 at Monteponi,
and in 1998 at San Giovanni. Consequent flooding of underground workings occurred in the district and also involved Campo
Pisano. In June 1998, as the water table rose from 160 to 20 m below sea level, the deep saline water mixed with the shallow
ground water at Monteponi and nearby mines. In the same period, an increase in dissolved metals (especially Zn, Cd, and Pb)
was observed under near-neutral pH conditions. Following peak concentrations, a marked decrease of Zn, Cd, and Hg occurred.
Dissolved Pb showed fluctuating concentrations over the monitoring period (1996-2005). In January 2000, when the water table
rose to 20 m above sea level, the salinity of ground water decreased significantly at all of the mines. Stratification caused
the more saline water at depth to settle three years after rebound started. Depth profiles carried out in 2005 at Monteponi,
San Giovanni, and Campo Pisano showed an increase in conductivity and dissolved metals in ground water at deeper levels, especially
at depths below sea level.After eight years of rebound, a marine component was still present at depth in ground water at San
Giovanni (about 2%), and to a lesser extent at Monteponi (about 0.4%). 相似文献
8.
A. K. Soni 《Mine Water and the Environment》2007,26(2):110-118
Abstract. Hydrogeological study of the Manikgarh and Naokari limestone mining areas, located in the Chandrapur region of central India,
indicate that the mining operations should not cause environmental problems. Conversion of hill mining to pit mining at the
Manikgarh Limestone Mine should be feasible and safe. At the Naokari Limestone Mine, a partial diversion of a seasonal stream,
the Bop Nala, has been proposed to simplify mining and maximize production; this can be done without significantly altering
the natural drainage pattern of the area and is not expected to have any adverse effects on the hydrological regime of area. 相似文献
9.
Abstract.
The discharge of highly mineralised mine waters with
enhanced
226Ra and
228Ra activity concentrations has
affected creeks, rivers, sediments, soils, and plants along the
Lippe River and its tributaries.
226Ra activity concentrations were
elevated in all water samples receiving mine water, with
activity concentrations gradually decreasing with increased
distance from the colliery due to dilution and chemical
precipitation of radium with barium. Increased concentrations of
radium and radium decay products were also measured in sediments
and flood-affected soils. The sediments show an enrichment of
226Ra up to a factor of 750, while
the contaminated soils only reach a factor of 10. In aquatic
plants, a 4-fold increase in
226Ra activity concentrations was
measured downstream of the discharge points. The contamination
of the river banks and adjacent floodplain with radium is
responsible for enhanced gamma dose rates, which, along with the
incorporation of soil by playing children, provide potential
radiation exposure to the public. 相似文献
10.
The Potential Importance of Mine Sites for Biodiversity 总被引:1,自引:0,他引:1
Lesley C. Batty 《Mine Water and the Environment》2005,24(2):101-103
Abstract Abandoned mine sites are typically viewed as environmental problems due to their negative impacts on local ecosystems. This paper presents an alternative viewpoint providing evidence of the potential importance of mine sites for supporting rare and threatened species from many of the major taxonomic orders. The potential importance of these species in remediation of polluted environments is also highlighted. 相似文献
11.
Abstract. Microbial heavy metal retention was studied using seepage
water sampled from a former uranium mining site in Eastern
Thuringia, Germany. The seepage water has a low pH and contains
high concentrations of metals, including uranium, rare earth
elements (REE), and other heavy metals. Microbial influence on
sorption and/or active uptake of heavy metals was studied using
REE patterns. Incubation of seepage water with the bacterium
Escherichia coli caused
sorption of heavy metals to biomass. Incubation with the fungus
Schizophyllum commune,
however, had a much more pronounced effect, including
significant fractionation of REE, pointing to the possibility of
a specific active uptake mechanism. Extraction factors and
fractionation coefficients are given to show the capacity of the
presented bioextraction for future applications. 相似文献
12.
Oliver Totsche Andrew Fyson Christian E. W. Steinberg 《Mine Water and the Environment》2006,25(4):204-213
Abstract. Microbial alkalinity production was evaluated as a method to prevent reacidification of neutralized mining lakes by acidic
ground and seepage water. We used 60 L mesocosms to represent the sediment and water column of a shallow acidic mine lake.
To enhance alkalinity production, acidic and neutralized lake waters were treated with either phosphorus (controlled eutrophication)
or organic matter (controlled saprobization). Controlled eutrophication could not produce enough autochthonous biomass as
substrate for microbial alkalinity production to change the acidity of the water. Chemical pre-neutralization of the acidic
water caused the inorganic carbon concentration to increase, but at the same time, hindered algae growth by reducing the availability
of phosphate by sorption to the freshly precipitated iron hydroxide. This effect was so strong that even high phosphorus additions
could not increase the algae biomass production. In contrast to controlled eutrophication, controlled saprobization produced
significant alkalinity. Despite inhibition of the most important alkalinity producing process, namely microbial sulfate reduction,
by low pH values, the microbial alkalinity production rate was not affected by pre-neutralization of the water column. Other
alkalinity producing processes raised the pH in the reactive zone until sulfate reduction was no longer inhibited. 相似文献
13.
Abstract.
Drainage systems in large surface mines are designed to
accomplish three basic objectives: keeping working conditions
dry, stable and safe; lowering hydrostatic pressure and
increasing the effective stress of soil to improve slope
stability; and ensuring pit floor workability. This can be
achieved with drainage facilities that include channels, water
collection sumps, and pump stations. We report the development
of a computer-aided system called Dewatering of Open Pit Mines
(DEWOP), which can assist open pit mine designers to solve
water-related problems. The system was developed in a Visual
Basic object programming language, taking advantage of
multi-user, open database connectivity, such as Microsoft
Access, for storage and processing of information. In tests at
coal and copper surface mines, it reduced drainage facilities
costs by 8%. 相似文献
14.
Tina Hartwig Michael Owor Andrew Muwanga Dieter Zachmann Walter Pohl 《Mine Water and the Environment》2005,24(3):114-123
Abstract The copper mine at Kilembe in the Ruwenzori Mountains in western Uganda ceased to operate in 1978 but a steady flow of contaminants,
including Cu, Co, Ni, Zn, Cd, and sulphate, continues to enter the Nyamwamba-Rukoki River, which passes through Queen Elizabeth
National Park, and finally flows into Lake George. Lake George is quite shallow, alkaline, and highly eutrophic. Measuring
mass-flow of contaminants, water, and suspended solids in the Rukoki River near Kasese allowed us to estimate their input
into Lake George. Grid sampling of lake sediments indicated that the contaminants settle near the two mouths of the river;
low concentrations in a drill core in the centre of Lake George indicate that further dispersion within the lake is small.
Sequential extraction experiments on lake sediments and lake water analyses suggest low bioavailability of the heavy metals.
We conclude that Lake George is a highly resilient system that efficiently immobilises contaminants. Though there is no health
risk for the population under present environmental conditions, a reduction of the contaminant load is desirable. 相似文献
15.
Robert S. Hedin 《Mine Water and the Environment》2006,25(3):146-152
Abstract: The net acidity of a water sample can be measured directly by titration with a standardized base solution or calculated from
the measured concentrations of the acidic and basic components. For coal mine drainage, the acidic components are primarily
accounted for by free protons and dissolved Fe2+, Fe3+, Al3+, and Mn2+. The base component is primarily accounted for by bicarbonate. A standard way to calculate the acidity for coal mine drainage
is: Acidcalc = 50*(2*Fe2+/56 + 3*Fe3+/56 + 3*Al/27 + 2*Mn/55 + 1000*10-pH)—alkalinity, where acidity and alkalinity are measured as mg/L CaCO3 and the metals are mg/L. Because such methods of estimating acidity are derived by independent laboratory procedures, their
comparison can provide a valuable QA/QC for AMD datasets. The relationship between measured and calculated acidities was evaluated
for 14 datasets of samples collected from mine drainage discharges, polluted receiving streams, or passive treatment systems,
containing a total of 1,484 sample analyses. The datasets were variable in nature, ranging from watersheds where most of the
discharges contained alkalinity to ones where all of the discharges were acidic. Good relationships were found to exist between
measured and calculated acidities. The average acidity measurement was 239 mg/L CaCO3 and the average acidity calculation was 226 mg/L CaCO3. Linear regressions were calculated for individual datasets and for the entire dataset. The linear regression for the entire
dataset was: Acidcalc = 0.98 * Acidmeas – 8, r2 = 0.98. The good correlation between calculated and measured acidity is the basis for an easy and inexpensive QA/QC for AMD
data. Substantial variation between measured and calculated acidities can be used to infer sampling or analytical problems. 相似文献
16.
Abstract.
This paper describes pilot scale tests of a novel process for the neutralisation of acidic mine water. Leachate from a waste coal dump was neutralised with limestone, and iron, aluminium, and sulphate were removed. Specific aspects studied were: the process configuration; the rates of iron oxidation, limestone neutralisation, and gypsum crystallisation; the chemical composition of the effluents before and after treatment; the efficiency of limestone utilisation; and the sludge solids content. The acidity was decreased from 12,000 to 300 mg/L (as CaCO3), sulphate from 15,000 to 2,600 mg/L, iron from 5,000 to 10 mg/L, aluminium from 100 to 5 mg/L, while the pH increased from 2.2 to 7.0. Reaction times of 2.0 and 4.5 h were required under continuous and batch operations respectively for the removal of 4 g/L Fe (II). The iron oxidation rate was found to be a function of the Fe (II), hydroxide, oxygen, and suspended solids (SS) concentrations. The optimum SS concentration for iron oxidation in a fluidised-bed reactor was 190 g/L. Up-flow velocity had no influence on the rate of iron oxidation in the range 5 to 45 m/h. Sludge with a high solids content of 55% (m/v) was produced. This is high compared to the typical 20% achieved with the high density sludge process using lime. It was determined that neutralisation costs could be reduced significantly with an integrated iron oxidation and limestone neutralisation process because limestone is less expensive than lime, and a high-solids-content sludge is produced. Full scale implementation followed this study. 相似文献
17.
Pollution of Water and Stream Sediments Associated with the Vale De Abrutiga Uranium Mine,Central Portugal 总被引:1,自引:0,他引:1
Abstract.
The Vale de Abrutiga uranium deposit, located in Central Portugal near the Aguieira dam reservoir, was surface mined. Low-grade ore and waste rock were deposited on permeable ground, close to the mine, and were not revegetated. A lake has formed in the open pit. Surface waters draining the mine site are acidic, have high conductivity, and high concentrations of U, SO42-, Zn, Fe, Mn, Ra, Cu, Th, and Pb. The groundwater and the water from the reservoir cannot be used for human consumption or irrigation. The sampled waters show higher contaminant concentrations in winter than in summer. Stream sediments have high geoaccumulation indices for U, Fe, Ag, Zn, Cr, Co, and Pb. In general, sediments bordering the dam reservoir have higher metal contents in winter than in summer. 相似文献
18.
Abstract. An analog pit lake (APL) test has been developed to
predict pit lake water quality following closure of an
equatorial copper-gold mine. The juvenile (0-9 years after
closure) pit lake (JPL) water budget will comprise 10% rainfall;
26% surface runoff; 40% wallrock runoff, and 24% deep
groundwater inflow. The mature (>65 years after closure) pit
lake (MPL) will consist of 39% rainfall; 29% surface runoff; 15%
wallrock runoff; 3% deep groundwater inflow, and 1% shallow
groundwater inflow, with the balance (13%) contributed by the
JPL. Wallrock runoff due to incident precipitation was
replicated in humidity columns, subaqueous wallrock leachate by
leaching columns of each rock type with groundwater, rainwater
by addition of sea salt to deionized water, and surface runoff
by a sample from a local creek. The solutions were combined in
aquaria and the appropriate fraction evaporated, 7% for the JPL
and 36% for the MPL. Electron microprobe analysis of
precipitates identified clays and Al, Cu, and Zn adsorbed to
ferrihydrite surfaces. A preliminary pit design resulted in an
acidic (pH 3.3) JPL containing 7 mg/L Cu. However, by modifying
the design to exclude a potentially acidgenerating andesite
unit, the JPL water quality improves (e. g., pH 6.7; Cu 0.002
mg/L). The MPL pH with the andesite would be 6.1 (Cu = 2.2
mg/L), while the final design results in a pH of 7.1 and 0.22
mg/L Cu. The APL test can also be used to corroborate numerical
models predictions and assess the efficacy of mitigation
alternatives. 相似文献
19.
Abstract. Nighttime high-resolution airborne thermal infrared
imagery (TIR) data were collected in the predawn hours during
Feb 5-8 and March 11-12, 1999, from a helicopter platform for
72.4 km of the Youghiogheny River, from Connellsville to
McKeesport, in southwestern Pennsylvania. The TIR data were used
to identify sources of mine drainage from abandoned mines that
discharge directly into the Youghiogheny River. Image-processing
and geographic information systems (GIS) techniques were used to
identify 70 sites within the study area as possible mine
drainage sources. The combination of GIS datasets and the
airborne TIR data provided a fast and accurate method to target
the possible sources. After field reconnaissance, it was
determined that 24 of the 70 sites were mine drainage. This
paper summarizes: the procedures used to process the TIR data
and extract potential mine-drainage sites; methods used for
verification of the TIR data; a discussion of factors affecting
the TIR data; and a brief summary of water quality. 相似文献
20.
Abstract. Surface water bodies are expected to form in several pits
at the Getchell Open Pit Mine after mining has ceased due to
inflowing surface and ground water. Predicting the long-term
geochemical behavior of the pit water is important in assessing
potential environmental effects. One of the pits, the Summer
Camp Pit, began to develop a pit lake in 1991 when dewatering
ceased and the pit was used to store water pumped from
underground operations. This provided a field-scale opportunity
to identify the controls on lake water chemistry and determine
the effects of seasonal mixing events on long-term chemical
behavior. During a five-year period (1996-2001), a number of
physical, chemical and mineralogical characteristics of the lake
were monitored with the intent of using this information as a
basis for predicting long-term geochemical behavior of future
lakes in the other pits. Seasonal and multiyear cycles were
identified within the water column. These cycles were influenced
by climatic changes and element and sediment loadings of inflow
to the lake. Stratification occurred, with the metalimnion or
active layer of the lake evolving from a low total dissolved
solids (TDS), alkaline water to a high TDS, neutral to mildly
acidic water, until turnover occurred due to density variations
between the metalimnion and epilimnion, completely mixing the
layers. A hypolimnion that formed has the potential to stabilize
metals in the basal sediments as sulfide minerals below a
chemolimnion in the lake. Longer-term events also appear to
involve the hypolimnion.The monitoring program demonstrated the dynamic nature of
a pit lake and how the complex limnology can affect seasonal
water quality. Such considerations are important in interpreting
water quality from pit lakes and in selecting monitoring data to
use when constructing mathematical models for predicting changes
in water quality. 相似文献