Uranium Tailings Acidification and Subsurface Contaminant Migration in a Sand Aquifer

1984 ◽  
Vol 19 (2) ◽  
pp. 55-89 ◽  
Author(s):  
N.M. Dubrovsky ◽  
K.A. Morin ◽  
J.A. Cherry ◽  
D.J.A. Smyth
Keyword(s):  
Heavy Metals ◽  
Vadose Zone ◽  
Inner Core ◽  
Pyrite Oxidation ◽  
Outer Zone ◽  
Low Ph ◽  
Small Stream ◽  
Sand Aquifer ◽  
Uranium Tailings ◽  
Stream Bed

Abstract Investigations of the geochemistry of inactive pyritic uranium tailings in the Elliot Lake Mining district of Ontario have focused on the Nordic tailings management area, where two impoundments are located in natural bedrock basins. The tailings are 8-12 m thick and overlie a localized deposit of glaciofluvial sands. Analyses of the solid, liquid, and gas phases in the vadose zone of the tailings show that gas-phase oxygen levels drop rapidly within 0.7 to 1.5 m of the surface, indicating rapid oxygen consumption during pyrite oxidation. Oxidation during the past 15 to 20 years has caused a marked depletion of near-surface pyrite. The oxidation of pyrite in the vadose zone imparts to infiltrating precipitation high concentrations of Fe, SO42-, various heavy metals, and a pH generally between 1.5 and 4. The acidic infiltration moves downward at a rate of 0.2 to 2.0 m/yr, displacing high-pH groundwater that originated as process water discharged from the mill. It now occupies the entire tailings thickness over a small area of the tailings. At one location a well-defined plume of high-Fe2+ tailings-derived groundwater has developed in the sand aquifer adjacent to the tailings. The plume consists of three zones: an inner core characterized by Fe > 5000 mg/L, pH < 4.8, and elevated concentrations of several heavy metals and radionuclides; an outer zone with Fe < 2500 mg/L, pH > 5.5, and relatively low concentrations of heavy metals and radionuclides; and a transition zone separating the two. Although the average linear groundwater velocity is about 440 m/yr near the dam, reactions such as mineral dissolution, precipitation and coprecipitation retard the migration of the front of the inner core, producing an observed frontal migration rate of approximately 1 m/yr. Groundwater from the outer zone of the plume flows laterally towards a small stream, where a portion of it is now discharging into the stream bed. The discharge results in the precipitation of amorphous ferric hydroxide on the stream bed. Most of the H+ produced by Fe precipitation is buffered, and only a moderate decrease in stream pH is observed. Inner zone conditions will not reach the stream unless input of low-pH groundwater from the tailings continues for several hundred years. Although the rate of pyrite oxidation in the Nordic Main tailings has been decreasing, there is sufficient pyrite in the tailings to generate high-Fe groundwater for several decades or more. Calculated groundwater migration rates indicate that in the next few decades acidic, low-pH groundwater will occupy the entire tailings thickness over most of the tailings area, causing an increase in the total flux of contaminated groundwater into the underlying aquifer. The outer zone of the plume has already arrived at a small stream, and acidification of the surface waters may increase if the Fe concentration in the groundwater seepage increases.

Contaminant migration in a sand aquifer near an inactive uranium tailings impoundment, Elliot Lake, Ontario

1982 ◽  
Vol 19 (1) ◽  
pp. 49-62 ◽  
Author(s):  
K. A. Morin ◽  
J. A. Cherry ◽  
T. P. LIM ◽  
A. J. Vivyurka
Keyword(s):  
Inner Core ◽  
Iron Hydroxide ◽  
Lake Ontario ◽  
Outer Zone ◽  
Water Levels ◽  
Main Concern ◽  
Contaminant Plume ◽  
Tailings Impoundment ◽  
Sand Aquifer ◽  
Uranium Tailings

An investigation of the movement of contaminated groundwater from inactive uranium tailings through a sand aquifer is being conducted at the Nordic Main tailings impoundment near Elliot Lake, Ontario. During 1979 and 1980, multilevel bundle-type piezometers were installed at several locations around the edge of the tailings impoundment. Chemical analysis of water samples from the bundle piezometers indicate that a major contaminant plume extends outward through a sand aquifer from the southeastern part of the Nordic Main impoundment dam.In the vicinity of the contaminant plume, the sand aquifer varies in thickness from about 9 to 15 m. The plume has two distinct segments, referred to as the inner core and the outer zone. The inner core, which has a pH of 4.3–5.0 and extends about 15 m from the foot of the tailings dam, contains several grams per litre of iron and sulfate, and tens of pCi/L of 226Ra and 210Pb. Water levels in piezometers within the inner core show that groundwater is moving horizontally, away from the tailings impoundment, with a velocity of up to several hundred metres per year. The outer zone, which extends a few hundred metres downgradient from the dam, is characterized by hundreds to thousands of milligrams per litre of iron and sulfate, less than 15 pCi/L of 226Ra, and a pH greater than 5.7. Comparison of 1979 and 1980 data shows that the front of the inner core is advancing a few metres per year, which is less than a few percent of the groundwater velocity. This retardation of movement of the inner core is caused by neutralization of the acidic water as a result of dissolution of calcium carbonate in the sand. With the rise in pH, precipitation of iron carbonate and possibly some iron hydroxide occurs and the contaminants of main concern such as 226Ra, 210Pb, and uranium are removed from solution by adsorption or coprecipitation.

Geochemical evolution of inactive pyritic tailings in the Elliot Lake uranium district

1985 ◽  
Vol 22 (1) ◽  
pp. 110-128 ◽  
Author(s):  
N. M. Dubrovsky ◽  
J. A. Cherry ◽  
E. J. Reardon ◽  
A. J. Vivyurka
Keyword(s):  
Heavy Metals ◽  
Water Table ◽  
Ferric Hydroxide ◽  
Low Ph ◽  
Geochemical Evolution ◽  
Geochemical Data ◽  
Secondary Aluminum ◽  
Tailings Impoundments ◽  
High Concentrations ◽  
Uranium Tailings

Geochemical data obtained between 1979 and 1983 from a network of piezometer nests and cores from three inactive uranium tailings impoundments in the Elliot Lake district indicate that oxidation of pyrite taking place in the shallow part of the zone above the water table is causing the chemistry of the pore water above and below the water table to change. A two-layer hydrochemical zonation has developed in which infiltration water from rain and snow has resulted in an upper zone of low-pH water with high concentrations of SO4, Fe, and heavy metals. This zone is gradually expanding downward at rates generally between 0.2 and 2 m/year, causing displacement of the original mill process water, which has neutral pH and low concentrations of heavy metals. High concentrations of Fe(III) at shallow depth in the zone above the water table indicate that ferric iron is an important oxidizer of pyrite in the presence of free oxygen.The pe of the groundwaters is controlled by the ferric–ferrous redox couple, and trends in the data indicate iron solubility control by siderite at high pH, by ferric hydroxide at moderate to slightly acid pH values, and possibly by jarosite at low pH. Aluminum solubility controls are complex, and precipitation of amorphous aluminum hydroxide, allophane, and basic aluminum sulfates may occur over different pH ranges. Transport of low-pH conditions is retarded relative to the rate of groundwater flow in the tailings, because of the buffering effect of small amounts of carbonate minerals added during tailings neutralization; primary aluminosilicates such as sericite; and secondary aluminum hydroxides.Field data show that the flux of dissolved iron from the vadose zone to the groundwater zone in the Nordic Main tailings has been decreasing in recent years. However, mass-balance calculations indicate a potential for the generation of high-Fe groundwater for several decades to several hundred years. A long-term potential for acid and iron production is also shown by data from two tailings impoundments that have been inactive 8–10 years longer than the Nordic Main area. Presently only a small portion of the Nordic Main and West Arm tailings areas has become acidic through the entire tailings thickness; however, under existing infiltration conditions more extensive acidification will occur in future decades.

A message from the depth: the origin of the amphibole crystal clots with pyroxene cores in the Late Pleistocene Ciomadul dacites, Romania

2021 ◽  
Author(s):  
Barbara Cserép ◽  
Zoltán Kovács ◽  
Kristóf Fehér ◽  
Szabolcs Harangi
Keyword(s):  
Inner Core ◽  
Magma Mixing ◽  
Outer Part ◽  
Mafic Magma ◽  
Outer Zone ◽  
Magma Reservoir ◽  
Explosive Eruptions ◽  
Innovation Fund ◽  
Amphibole Crystal ◽  
Crustal Magma

<p>Identification of trans-crustal magma reservoir processes beneath volcanoes is a crucial task to better understand the behaviour and possible future activities of volcanic systems. Detailed petrological investigations have a fundamental role in such studies. Dacitic magmas are usually formed in an upper crustal magma reservoir by complex open-system processes including crystal fractionation and magma mixing following recharge events. Conditions of such processes are usually constrained by crystal-scale studies, whereas there is much less information about the petrogenetic processes occurring in the lower crustal hot zone. Here we provide insight into such processes by new results on amphibole crystal clots found in dacitic pumices from an explosive volcanic suite of the Ciomadul volcano, the youngest one in eastern-central Europe.</p><p>Amphibole is a common mineral phase of the Ciomadul dacites, occuring as phenocrysts and antecrysts, but occasionally they also form crystal clots with an inner core of either pyroxene or olivine with high Mg-numbers. Olivine is observed mostly in the 160-130 ka lava dome rocks, whereas the younger explosive eruption products are characterised by orthopyroxene and clinopyroxene. Such mafic crystal clots are most common in the pumices of the earliest explosive eruptions, which occurred after long quiescence at 56-45 ka. The most common appearance has high-Mg pyroxene core (mg#: 0.76-0.92) rimmed by amphibole. Two types of amphibole are found in such clots: irregular zone of actinolite to magnesio-hornblende directly around orthopyroxene and high Mg-Al pargasitic amphibole as the outer zone. Several crystal clots contain smaller amphibole crystals with diffuse transition to clinopyroxene at the inner part and complexly zoned amphibole with biotite inclusions in the outer part. These amphibole and pyroxene have lower Mg-number (< 0.80), and higher MnO content (up to 0.52 wt%) than the most common type. In both cases, amphibole could be a peritectic product of earlier-formed pyroxenes, which reacted with water-rich melt at higher and lower temperatures, respectively. Actinolite to magnesio-hornblende at the contact represents a transitional phase between pyroxene and the newly formed amphibole. In a few cases, crystal clots contain amphibole inclusions in pyroxene macrocrysts. These amphiboles have a particular composition not yet reproduced by experiments: they have high mg# (>0.86), but low tetrahedral Al (0.9-1.0 apfu) and usually high Cr content (Cr<sub>2</sub>O<sub>3</sub> is up to 0.9 wt%), similar to the orthopyroxene and clinopyroxene hosts (0.26-0.71 and 0.78-0.89 wt%, respectively). We interpret these amphiboles as an early formed liquidus phase crystallized along with pyroxene from an ultra-hydrous mafic magma. Occasionally, crystal clots are complexly zoned amphibole macrocrysts with dispersed clinopyroxene inclusions. The amphibole has a wide compositional range, usually with high Mg-Al pargasitic core. These amphiboles could have formed by peritectic reaction between clinopyroxene and a water-rich melt.</p><p>The observed mafic crystal clots in the dacites indicate the presence of strongly hydrous mafic magmas accumulated probably at the crust-mantle boundary. During mafic recharge, volatile transfer may contribute to the crystal mush rejuvenation at shallow depth and triggering explosive eruptions.</p><p>This research was financed by the Hungarian National Research, Development and Innovation Fund (NKFIH) within K135179 project.</p>

scholarly journals Probiotic Lactobacillus sp. with bioremediation potential of toxic heavy metals

2018 ◽  
Vol 34 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Sangita Ahmed ◽  
Md Rafiqul Islam ◽  
Jannatul Ferdousi ◽  
Tabassum Samia Iqbal
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Industrial Development ◽  
Biochemical Properties ◽  
Low Ph ◽  
Drug Resistant ◽  
Toxic Heavy Metals ◽  
Human Gut ◽  
Probiotic Lactobacillus ◽  
Lactobacillus Spp

Pollution of the environment and food with toxic heavy metals is being intensified in Bangladesh with industrial development. Consumption of foods and water contaminated with heavy metals imposes threat to human health. Aiming to find a solution to this problem, the present study focuses on probiotic Lactobacillus spp. with potential to remove heavy metals from environment as well as human body. A total of three Lactobacillus spp were isolated from curd samples and were identified based on their morphological and biochemical properties. These isolates were tolerant to low pH and bile salt which aids in their application in human gut. All isolates could tolerate 600 ppm chromium, 400 ppm lead, 400 ppm copper and 400 ppm zinc. The heavy metal tolerant Lactobacillus spp were also multi drug resistant and showed 100% resistance to Azithromycin, Cloxacillin, Gentamicin, Vancomycin, Streptomycin, Nalidixic acid, Trimethoprim-Sulfamethoxazole and Penicillin, while 100% sensitivity was observed to Imipenem. Bangladesh J Microbiol, Volume 34 Number 1 June 2017, pp 43-46

Role of the biotic compartment in the transfer of zinc through the vadose zone - application to an infiltration system

1999 ◽  
Vol 39 (2) ◽  
pp. 209-215
Author(s):  
C. Hébrard ◽  
C. Delolme
Keyword(s):  
Heavy Metals ◽  
Pseudomonas Putida ◽  
Vadose Zone ◽  
Considerable Importance ◽  
Urban Stormwater ◽  
Elution Curves ◽  
Stormwater Infiltration

Relatively little is known about the influence of microorganisms which develop in urban stormwater infiltration basins on the transfer of heavy metals, whereas many reports have emphasized their importance in the mechanisms of retention or solubilization of these elements. We therefore examined the transfer of zinc solutions (2-20 ppm) at different pH (4-7) by columns of sterile sand or sand colonized with Pseudomonas putida. The shape of the elution curves shows that the biofilm adsorbed zinc, causing its elution to be retarded. Adsorption seemed to be reversible, except at pH 6 and 7, and non-instantaneous. Consequently, the stormwater infiltration speed may be of considerable importance.

Facultative estivation in the water strider Gerris remigis

1991 ◽  
Vol 69 (5) ◽  
pp. 1412-1413 ◽  
Author(s):  
R. Stimson Wilcox ◽  
Hilmar A. Maier
Keyword(s):  
New York ◽  
Water Strider ◽  
Small Stream ◽  
Stream Bed

Marked individuals of the water strider Gerris remigis estivated facultatively during summer in damp areas underneath stream-bed rocks when a pool in a small stream in New York twice went dry.

Effect of low pH, heavy metals and anions on chlorophyll degradation in the lichen Ramalina duriaei (de not.) bagl.

1992 ◽  
Vol 32 (3) ◽  
pp. 229-241 ◽  
Author(s):  
J. Garty ◽  
Y. Karary ◽  
J. Harel
Keyword(s):  
Heavy Metals ◽  
Low Ph ◽  
Chlorophyll Degradation

Biomass production for the removal of heavy metals from aqueous solutions at low pH using growth-decoupled cells of a Citrobacter sp.

1995 ◽  
Vol 35 (1-3) ◽  
pp. 73-92 ◽  
Author(s):  
L.E. Macaskie ◽  
C.J. Hewitt ◽  
J.A. Shearer ◽  
C.A. Kent
Keyword(s):  
Heavy Metals ◽  
Aqueous Solutions ◽  
Biomass Production ◽  
Low Ph ◽  
Removal Of Heavy Metals

Affinity Extraction into CO2. 2. Extraction of Heavy Metals into CO2from Low-pH Aqueous Solutions

1998 ◽  
Vol 37 (12) ◽  
pp. 4768-4773 ◽  
Author(s):  
J. Li ◽  
E. J. Beckman
Keyword(s):  
Heavy Metals ◽  
Aqueous Solutions ◽  
Low Ph
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