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Bioaccumulation and bioavailability: keys for quality
ecosystem
European Joint Master in Water and Coastal Management 2016
5/3/16 2
Today’s lecture• Metals origin. sediments key environmental compartment• Normalisation• Chemical speciation. Sequential extraction.• Methods of sequential extraction• Preliminary studies within BCR• Three-step sequential extraction escheme
- Tessier scheme- BCR
• New study for metals
5/3/16 3
Introduction
Two many reason for studying chemical behavior of metalin marine environment: to understand the biological andgeochemical cycling of these elements.– Biological cycling : bioaccumulation, elimination, bioavailability,
toxicity, biotransformation and biomagnification– Geochemical cycling: transport, adsorption, desorption,
precipitation, dissolution and complexation of metals.
The tendency which a metal participates in a geochemical orbiological process depend on the physicochemical forms of metal in amarine environment. Each different physicochemical for an element(speciation) can exhibit different bioacumulation trend, toxicity….
However to integrate metal chemistry, bioaccumulation and toxicity inmarine environment is a pending task
403/05/2016
METALS ORIGIN. SEDIMENTS KEY ENVIRONMENTAL COMPARTMENT
METAL CICLE IN MARINE ENVIRONMENT
Terrestrial environment
Seawater
VolatilizationInputs
Biological Factor
Degradation Uptake
Sediment
Precipitation
Disolution
Ingestion
Decomposition
Metal enter from the terrestrial to marineenvironment as input from the natural oranthropogenic sources. A metal may assume avolatile form and escape back to the terrestrialenvironment.
Metal inputs from terrestrial emissions may dissolvedin seawater or be directly transported to the marinesediments. If a metal exceeds a critical solubility limitin seawater, it may precipitate as a solid phase oradsorb on particulate and settle to the sediment.
The biological factor, marine biotafor example, can bioacumulatemetals from seawater and releaseit back to the seawater ondegradation of detrital biogenicmatter
0 10 20 30 40 50 60-30
-20
-10
10 15 20 25 30
0 10 20 30 40 50 60-30
-20
-10
0.05 0.1
0.15 0.2
0.25
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Metals originnatural
anthropogenicAgricultureIndustrial…
Sediment play an important role in aquatic systems both
Sink: contaminants can be stored
Source: to the overlying water and to biota
METALS ORIGIN. SEDIMENTS KEY ENVIRONMENTAL COMPONENT
ü Sediment are a good indicator of water quality and record the effects of anthropogenic emissions and are widely used in environmental studies.
ü Metals trend to be trapped in sediment (Forstner and Wittman, 1979; Tessier and Campbell, 1988). Adsorption of toxic trace metals are taken to the sediments by the settling of particles in seawater (clays, Fe and Mn oxides or hydroxides, calcium carbonates and/or organic matter). It reflect the grade of contamination of the environment
anthropogenic Sediments: reflect the grade of contamination
Changes of phisico-chemical parameters, bioturb… Metals to water
Normalisation
Improving interpretations are obtained by normalising metal concentrations in sediments to percentage of a given grain size, Al, Fe, OC.
Example for Al:Sediment A :100 µg/g dw Cu in fine-grained sedimentSediment B: 10 µg/g dw Cu in sandy sediment
First approach: Sediment A contaminated by Cu
Second approach: Al indicator of claysSediment A: 5% AlSediment B: 0.5% AlSediment A: Cu/Al =20Sediment B: Cu/Al =20Organisms ingesting sediments at site B are exposed to similar Cu concentrations to organisms at site A
AVS-SEM
Biogeochemical differences with the greatest implication for metal chemistry occur between the oxic and anoxic zones.
Extraction with HCl will operationally quantify at least some fractions of the amorphous Fe sulphide in sediments (AVS)
Metal are also released during the acid treatment (SEM)Total amount (metals) released can be compared to AVS moles
If SEM>AVS other metals forms besides sulphur are presentIf AVS>SEM, metals is associated with sulphides
14 03/05/2016
Sequential Extraction Procedure for sediment analysis
SAMPLE PRETREATMENT
Recommended procedure for marine sediment (Loring and Rantala, 1992)
ØSamples are wet – sieved through a 63 µm mesh nylon sieve Homogenized
Normalized
ØSamples for chemical analysis are dried at 55ºC to constant weight and were ground to a fine powder agate mortar
63 µm
Dried sediment(55ºC)
ØSediment samples are stored at room temperature
Name:
Date:
For Chemical analysis
63 µm
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Sequential Extraction Procedure for sediment analysis
ØSample sediment pre-treatment.
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• Currently: Sediment analysis techniques for evaluation of environmental impact of contaminant
sediments has changed from the determination of total concentrations towards a more
sophisticated fractionation of the sediment compounds
CHEMICAL SPECIATION. SEQUENTIAL EXTRACTION
• The use of the total concentration as a criterion to assess the potential effect of sediment
pollution or to discuss their mobility implies that all metal forms have the same impact on the
environment: ACLEARLY UNTENABLE ASSUMPTION (Tessier et al., 1979)
• There are many ways for metals to associate with the sediment matrix:
they can be ----- adsorbed at the surface
----- incorporated into mineral phases
----- occluded in amorphous matter
• It is recognized the importance of Trace metals chemical forms. The chemical form provideinformation to understand their geochemical behavior and biological availability
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• In unpolluted sediments trace metals are mainly bound to silicates and primary minerals,
relativaly inmobile species.
• In polluted sediments trace metals are generally more mobile and bound to other sediment
phases
• Measurement of this “speciation” is very difficult due to the intrinsic complexity of the sediment-
water-biota-system. Different variables determine the behavior of these system: adsorption,
desorption, precipitation…
SEQUENTIAL EXTRACTION
• CHEMICAL SPECIATIONmobilizationFood chain
CHEMICAL SPECIATION. SEQUENTIAL EXTRACTION
• It is difficult to determine the specific sediment-metal association. Exits some limitations and its
why indirect methods have been developed.
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CHEMICAL SPECIATION. SEQUENTIAL EXTRACTION
Sequential extraction
Use different extractants to obtain information on the modes of association of metals with the sediment
Disadvantage
-The distribution of metals in the different fraction does not necessarily reflect theirassociation with a discrete geochemical phase but, rather, is operationally defined bythe extraction method
- These methods have been criticized, mainly for their lack of selectivity, validation andreadsorption problems (Kheboian and Bauer, 1987; Nirel and Morel, 1990)
Advantage
- They can differentiate between samples that present similar total metal concentrations
- Offer information about the origin, mode of occurrence, physicochemical andbiological availability, mobilization and transport of metals in the environment (Luomaand Jeene, 1976; Tessier and Campbell, 1987)
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Sequential Extraction Procedure for sediment analysisent
Different sequential extraction schemes have been proposed for
the determination of binding forms of trace metals in sediments
BCR TESSIER
METHODS OF SEQUENTIAL EXTRACTION
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From sequential extraction schemes described in the literature, the classical method ofTessier has been widely apply in marine sediment.
2ª
3ª
4ª
5ª
FRACTIONS
1ª Exchangeable
NaOAc/AcOH pH=5
NH2OH. HCl (0.04M) in 25% HOAc
H2O2(30%), NH4OAc (3.2M)
3:1 aqua regia : HF (B(OH)3
MgCl2 1M pH=7
EXTRACTANT
Carbonate
Hydrous oxide of Fe and Mn
Organic matter
Residual
Several modifications to the Tessier scheme have been proposed by different authorsin order to improve the lack of selectivity of the extractant agents towards specificgeochemical phases of the sediments (Förstner, Meguellati)
TESSIER SCHEME
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Sequential Extraction Procedure for sediment analysisent
PRELIMINARY STUDIES WITHIN BCR
• The main problem of sequential extraction appears when results from different procedure arecompared Reference material it is necessary to control the quality of measurements
• The BCR Program stated in 1987. Sequential extraction schemes was a first step towards theharmonisation and the preparation of certified reference materials for Cd, Cr, Cu, Ni, Pb and Zn.• Different sequential extraction schemes were tested by four laboratories on seven sediment.The procedures tested were
Modified Tessier procedure by Förstner
Meguellati scheme with six and five steps
Short method Förstner and Salomon with three step
• Results show that most of the metals were extracted in the first step in the most mobile phase.It was shown that all the tested procedures would be able to classify the predominant nature ofthe sediment and allow recommendations to be made for their use
It is possible define a simple sequential extraction scheme for the characterisation of the sediments and it was recommended that a reference material be prepared for quality control proposes.
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Sequential Extraction Procedure for sediment analysisent
A COMMON THREE-STEP SEQUENTIAL EXTRACTION ESCHEME
A three –step sequential extraction procedure was proposed by a group of European experts (ETMESS, 1992)
Two river sediment----intercomparison exercises with 20 laboratories
Reference materials were prepared according the flow chart by theEnvironment Institute of the Joint Research Centre in Ispra, Italy.
Operational details to be added to the protocol in order to improve thereproducibility among the laboratories
Homogeneity and stability studies corroborated the feasibility about thepossibility of certification of extractable trace metal amounts following astandardised sequential three step extraction procedure
The BCR constituted the first available tool for the validation ofmethodology in the sequential extraction research field
23 03/05/2016
ACID-SOLUBLE PHASE (FRACTION 1): This phase is made up and bound to carbonatesthat are able to pass easily to the water column. It is the fraction with the most labile bond tothe sediment and the most dangerous for the environment
REDUCIBLE PHASE (FRACTION 2): Consists of metals bound to iron and manganese oxidesthat may be released if the sediments changes from the oxic to the anoxic state, which may becaused for example by the activity of the microorganisms present in the sediment
OXIDABLE PHASE (FRACTION 3): This phase shows the amount of metal bound to organicmatter and sulphides that can be released under oxidising conditions, for example, if thesediment is resuspended by dredging, currents….
RESIDUAL (FRACTION 4): Metal associated with minerals forming part of their crystalinestructure
THREE-STEP SEQUENTIAL SCHEME PROCEDURE
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STEP 2Extracting agent: NH2OH.HCl 0.5M (pH 1.5, HNO3 2M)Extracting: m/v= 1:4016 h end-over-end shaker
STEP 3Digestion: H2O2 30% (Room T and 85ºC)Extarcting agent: NH4CH3COO 1M (pH 2, HNO3)Extraction: m/v= 1:5016 h end-over-end shaker
RESIDUE STEP 2
FINAL RESIDUE
EXTRACT STEP 2
EXTRACT STEP 3
Centrifugation and washing
Centrifugation and washing
STEP 1Extracting agent: HCH3COO 0.11MExtracting: m/v= 1:4016 h end-over-end shaker
Centrifugation and washingEXTRACT STEP 1
RESIDUE STEP 1
SEDIMENT
The BCR programme (1987)
25 03/05/2016
Acid soluble phase (fraction 1).
1 gram of sediment
100
ml c
entri
fuge
tu
be
40 ml acetic acid
(0.11mol L-1)
16 h of shaking
centrifugation
20 ml distilled water
Shaken 15 min and centrifuged 20 min
SUPERNATANT
RESIDUE
This phase: exchangeable metals and bound to carbonates that are able to pass easily to the water column
Fraction 2
Emergent contaminants
ØPharmaceuticals ingredientsØNanoparticles
ØNanoparticle is a substance at least one dimension between1 and 100 nm.
ØMore than 800 products are on the market contain or utiliza nanomaterials.
ØAddress regarding to human and wildlife safety of NMs.
ØNMs characteristics play in bioavailability, absorption, distribution, excretion and toxicity.
ØToxicity (dissolution, surface area, size, size distribution and shape)
Question of sizeThe size is important
Why?
More atoms on the surface
Increasing chemical reactivity
Smaller is more velocity
Increase of storing capacity
Change in the mechanical propierties
Quantum effects
Investement in nanotechnology
NNI (2000-2010) 12,000 millons $
Similar initiatives in other countries (Japan, Germany, UK, Canada)
FP6 y FP7 EU
Nanomarket is a big market 2015 2 billions €
Sapina, 2000 network Nanoscience and NanoSpain
Strategic Action of Nanoscience and Nanotecnology
0
20000
40000
60000
80000
100000
120000
2012 2011 2010 2009 2008 2007 2006 2005
Nanoparticles
Material Sciences
Chemistry
0
1000
2000
3000
4000
5000
6000
2012 2011 2010 2009 2008 2007 2006 2005
Environmental Sciences
Ecotoxicology
ENPs clasification
It is based on chemical composicion and additional information about size and morphological chracteristics
Carbon-based ENPs
Mineral ENPs
Fullerenes (Buckminster fullerenes, Carbon nanotubes, etc.)ENPs metálicas (Ag, Au, Fe)Oxides (TiO2, Fe-oxides)Complex compounds (Co-Zn oxido Fe)Quantum dots (CdSe)Organic polymers
Gold nanoparticle Silver nanoparticle
Metallic nanoparticles can be single elements (Ag, Au, Cu, Fe, etc.), metallic oxides (Al2O3, TiO2, ZnO, etc.) y multielemental oxides.www.nanowerk.com
ENPs –based on OC
Nanoparticles of iron zero-valent iron y nanoclays
Exposure Period
3H 6H 12H 24H 7 Days 14 Days 28 Days
Au C
once
ntra
tion
(ug
g-1)
0
2
4
6
8
10
12
14
C_MA A5_MA N3_MA N30_MA
Exposure Period
3H 6H 12H 24H 7 Days 14 Days 28 Days
Au C
once
ntra
tion
(ug
g-1)
0
20
40
60
80
100
C_DG A5_DG N3_DG N30_DG
Exposure Period
3H 6H 12H 24H 7 Days 14 Days 28 Days
Au C
once
ntra
tion
(ug
g-1)
0
5
10
15
20
25
C_GI A5_GI N3_GI N30_GI
0 1 2 3 4 5 6 7 8 9 100
10
20
30
40
50
60
70
80
90
cps
keV
muestra 3 qo3
Au
Os
Cu
UCl
Au
Cu
O
C
DGtreatedwithAuNP30ug/L.Cut300nmmedido intransmisionwayinSEM-FEGEDXofelectrodenseparticle,Goldcanbeclearlyidentified
5/3/16 40
Bibliography• 1 References:
– Gleyzes C, Tellier S, Astruc M. 2002. Fractionation studies of trace elements in contaminated soils and sediments: a review of sequential extraction procedures. 2002. Trends in Analytical Chemistry 21(6-7): 451-467.
– Vijver MG, van Gestel CAM, Lanno RP, van Straalen NM, Peinnenburg WJGM. 2004. Internal Metal Sequestration and its ecotoxicological relevance. Env. Sci. Technol. 38(18): 4705-4712
– Tessier, A., Campbell, P.G.C y Bisson, M., 1979. Sequential extraction procedure for the speciation of particulate trace metals. Anal. Chem. 51: 844-850
– Tessier, A., Campbell, P.G.C y Bisson, M., 1982. Particulate trace metals speciation in stream sediments and relationships with grain size: implication for geochemical exploration. J. Geochem. Explor. 16:77-104
• 2 Books / Reports:– Methodologies for soil and sediment fractionation studies. (Ph. Quevauviller ed.). RSC 2002,
180 pp.
http://julianblasco.weebly.com
44 03/05/2016
THE END
Thank you verymuch for your attention