Upload
others
View
4
Download
0
Embed Size (px)
Citation preview
Lead and Copper Isotopes in
Environmental
Sciences
Martin Mihaljevič Institute of Geochemistry, Mineralogy and Mineral resources
Faculty of Science, Charles University
IGCP/SIDA 594 Training course, University of the Witwatersrand, Johannesburg, July 13-15, 2013
• Metals are global contaminants
• Geochemical archives
• Pb and Cu isotopes
• Metodological approaches
• Practical applications
Introduction
Lead
Renberg et al. Holocene, 11, 511-516
Lead – global contaminant
Sweeden
Spain
Swiss
• Total concentration and mineralogical form is
not sufficient for evaluation of contamination
• Tracing of sources (local, global), kinetics of
processes, residence time are of great
concerns
• Convenient approach provides isotopic study
Introduction
I. Short lived radionuclides 210Pb (t1/2 = 22 years) 212Pb (t1/2 = 10 hours)
214Pb (t1/2 = 26.8 min)
II. Products of U and Th decay 206Pb, 207Pb a 208Pb
III. 204Pb (1%) stable, non radiogenic , primordial, constant
abundance on Earth in time
parent isotope Pb isotope decay half time
(years)
238U 206Pb (24%) 4,466 x 109
235U 207Pb (23%) 0,704 x 109
232Th 208Pb (52 %) 1,401 x 1010
Pb isotopes
210Pb cycle
210Pb is decay product
of 222Rn
Mihaljevič et al. (2006) Sci Tot Environ 372, 334-344.
Ettler et al. (2008) Atmos Environ, 42, 5968-5977.
Dating of young sediments, peat deposit
(~ 200 years)
I. separation of U a Th phases, which produce
highly radiogenic ratio
II. separation of Pb (sulphides) or phases
containing low amount of U, Th)
III. separation of Pb simultaneously with U a Th
206Pb, 207Pb, 208Pb a 204Pb isotopes
Origin of Pb Isotopic signature of geomaterials
depends on
• age of U, Th source
• separation of Pb (or U, Th) from the source
• one important source of Pb (eg. lithogical, ore)
• mixing of different sources
• combination of Pb and parent isotopes of U
and Th
• isotopic composition of the most important
sources
Origin of environmental Pb signature
A three-isotope plot
Mihaljevič et al. (2009) Int J Coal Geol 78, 38-46.
Ettler et al. (2004) Anal Bioanal Chem 378, 311-317.
Komárek et al. (2008) Environ Int 34, 562-577.
Material and methods
peat profiles
sedimentary profiles
soils
tree rings
soil and atmospheric waters
soils vs. biomass
Measurement of Pb
isotopic composition
Quadrupole based ICP MS (VG Elemental PQ3)
• the most preferred 206Pb/207Pb
ratio is used in environmental
science
• normalisation to 204Pb
(206Pb/204Pb,
207/Pb204Pb...) yields largest
variability between reservoirs
Pb mass spectrum
• important source of Pb
• different isotopic
composition
• depends on Pb source and U
U content
Mihaljevič et al. (2009) Int J Coal Geol 78, 38-46.
Coals
• source determination, mixing of sources
• determination of Pb penentration rate
Ettler et al. (2004) Anal Bioanal Chem 378, 311-317.
Soils
forest soil tilled soil
• changes in Pb source
Kadlec et al. (2009) Holocene, 19, 499-509
Morava River floodplain
Sediments
• source identification in industrial and remote areas
• deposition rates calculation
Mihaljevič et al. (2006) Sci Tot Environ 372, 334-344.
Peat deposits
• trees in temperate climate
have visually distinguishable
tree rings
• Pb is a suitable element for
dendroanalyses
• Pb source identification
by isotopic study
Tree rings
Mihaljevič et al. (2008) WASP 188,
311-321.
• source of Pb
• root uptake/interception
Mihaljevič et al. (2006) J Geochem Explor 88, 130-133
soils Prague
soils Most
Roudnice
wines
Plants- products
Zambia Copperbelt
Cu, Co ores
metallic and SO2
pollution
Ettler et al. Geoderma 164
Ettler et al. Geoderma 164
Copper
Cu
essential micronutrients
(enzymes, proteins)
also pollutant
Stable 63Cu (69.17 %) and 65Cu (30.83
%)
(27 radioisotopes)
Analytical techniques
Shields et al 1964, 1964 first
measurement of Cu isotopic ratio
First precise measurement of Cu
Merechal et al (1999) Chem Geol
Separation of Cu
- basic anion exchange resin
(BioRad, AG1-X) the separation of Cu from
matrix in Cl forms
Measurement
MC ICP MS with magnetic sector analyser
Standard NIST 976
bracketing or interelement (62Ni, 60Ni)
correction
Cu isotopic
Composition
of Cu minerals
Albarede (2004)
Meteorites – Luck et al (2004)
3 Cu reservoirs i) Earth like reservoir,
ii) Carbonaceous chondrites
iii) Mixture of i) and ii)
Luck et al GCA (2004)
Rocks
MORB, OIB – igneous processes are
inefficient in Cu fractionation
Sediments
Deep sea clays 65Cu -0,9 to – 3 ‰
preferential reductive dissolution of light
Isotope
Manganese nodulese preferential sorbtion
of heavy 65Cu
The 65Cu of natural materials Bigalke et al SSSAJ 2010
Fractionation of Cu isotopes Bigalke et al SSSAJ 2010
Albarede (2004) Rev Geochem Min
Soils
Bigalke et al. GCA 2010
Cu mg/kg 65Cu
Organic horizons are enriched in Cu,
and 65Cu
Pb and Cu isotopic study in Kombat
Kombat
Cu, Pb and Zn deposit
bornite chalcopyrite, galena, sphalerite,
tennantite, pyrite and,
chalcotite, digenite, malachite, covellite,
cuprite, native Cu and Ag
Closed in 2008, problems with flooding
Tailing dam 213 000m2
Sample Depth Fe tot Mn tot Cu d65Cu SD Pb
206Pb/207Pb SD
208Pb/206Pb SD
(cm) (mg kg -1) (mg kg -1) (mg kg -1) (‰) (mg kg -1)
K1 wet 0-20 4174 3811 1711,0 0,667 0,007 552,0 1,152601 0,002665 2,112931 0,007179
40-60 4452 5335 2625,0 0,820 0,006 827,0 1,151611 0,003431 2,107413 0,005186
160-180 13365 4038 4794 0,377 0,023 1904 1,151019 0,002969 2,10715 0,006333
K2 dry 0-20 7965 4349 1851 0,678 0,001 989 1,147687 0,003487 2,113504 0,008791
40-60 5670 2810 1199 0,612 0,008 689 1,150223 0,003994 2,118687 0,006194
160-180 4921 3664 2915 0,144 0,011 1120 1,14847 0,003902 2,11896 0,004147
Sample Depth TC TS Mineralogy
(cm) (%) (mg kg -1)
K1 wet 0-20 9,37 <100 Fe-dolomite, calcite, quartz, apatite, malachite, hematite rutile, muscovite
40-60 10,20 <100 Fe-dolomite, calcite, quartz, goethite, malachite, hematite, muscovite
160-180 10,11 <100 goethite, apatite, malachite, Fe-dolomite, calcite, quartz, hematite, rutile, muscovite
K2 dry 0-20 10,32 200 Fe-dolomite, calcite, goethite, apatite, malachite, quartz, hematite, muscovite
40-60 8,97 100 Fe-dolomite, apatite, calcite, goethite, quartz, rutile, malachite, hematite, muscovite, cerusite
160-180 9,23 300 fe-dolomite, apatite, calcite, quartz, rutile, cerusite, goethite, malachite, hematite, muscovite,
Tailing material
Cutanic luvisol Petrocalcic Chernozem
Cu and Pb speciation in tailing water
CuCO3aq (82 %), Cu(OH)aq+ (6.5%), Cu2+
(5.5 %), CuSO4aq (3 %), Cu(CO3)22-,
Cu(OH)2 (0.6%), CuHCO3+ (0.4 %).
uncharged Cu complexes (85.7%)
PbCO3 (64.2 %), PbSO4 (9.9 %),
Pb2+ (8.374 %), PbOH+ (8.1 %), PbHCO3+
(7.11), Pb(SO4)22- (0.5 %) and Pb(OH)2
(0.12 %) uncharged complexes 75%
of all forms of Pb
Leachate solution Lin STOTEN (1997)
Model equilibration with soil particles
(quartz, kaolinite, illite and hematite)
no data for SOM or Mn oxides
Cu in solution
< 3% Pb in solution
Soils contain birnesite and todorokite and
1,75-44 g/kg TC
Cu and Pb
correlation with
Mn contents
in soils
• metals are more mobile in luvisols compared
to chernozem
• Cu is more mobile than Pb
• basement rocks have negative 65Cu values,
the flotation waste of the tailing material has
positive 65Cu values
• the transformation of Cu to mobile forms 65Cu ↓
• bonding to Mn oxides in deeper parts 65Cu ↑
• plant activity 65Cu ↓
•The higher accesibility of ICP MS has led
to higher number of isotopic studies
•Pb isotopic composition were succesfully
used in environmantal studies as a
tracers
•Geochemical archives are powerful tool
for studying polution history
•Decline of Pb deposition since sewenties
Conclusion I
Conclusion II
• Determination of fractionation of
non-traditonal isotopes (Cu) are
dependent on very good resolution of MS
• Cu isotopic composition are succesfully
used in environmantal studies.
• Cu iso can serve as tracer of source
material
• Cu isotopes are successfully used for
Identification of biogeochemical cycling
Colleagues
V. Ettler, O. Šebek, L. Strnad, J. Jehlička, V. Chrastný (Č.
Budějovice), A. Vaněk, M. Komárek (ČZÚ) T. Navrátil (GÚ AV), T.
Kyncl, T. Grygar, D.R. Bowes, E. Dambrine, P. Povondra,
M.Fayadová
Students
Funding GAČR, GAUK, Phare, Ministry of Education...
Acknowledgements
Thank you for your attention