Bioaccumulation and bioavailability: keys for quality

ecosystem

European Joint Master in Water and Coastal Management 2016

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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

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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

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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

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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

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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

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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)

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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

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Nanoparticles

Material Sciences

Chemistry

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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)

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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)

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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)

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C_GI A5_GI N3_GI N30_GI

0 1 2 3 4 5 6 7 8 9 100

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cps

keV

muestra 3 qo3

Au

Os

Cu

UCl

Au

Cu

O

C

DGtreatedwithAuNP30ug/L.Cut300nmmedido intransmisionwayinSEM-FEGEDXofelectrodenseparticle,Goldcanbeclearlyidentified

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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

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THE END

Thank you verymuch for your attention