The relationship between the chemistry

of environmental waters and the

composition of biological fluids and

tissues in marsh turtles

Paolo Censi University of Palermo – Department of Earth and Marine Sciences

Via Archirafi, 36 90123 Palermo (Italy)

paolo.censi@unipa.it

INNOVATIVE TECHNOLOGIES FOR THE SUSTAINABLE MANAGEMENT AND POLLUTION REDUCTION OF WATER RESOURCES

Ferrara, 02-06 settembre 2013

Tekr¤l-ktr O

Shallow and groundwaters

Geochemical markers

Recognition of water masses and their sources

Salinization processes

Evaluation of geothermal resources

Biodiversity

Description of environmental-geochemical processes

Environmental effects on biological species

Treated geochemical arguments

interface processes

A new point of view to evaluate processes

involving the occurrence of a some interface

between to different media. This approach

will allow us to simply consider rock-water

interactions as a particular phenomenon

where the considered interface occurs

between Lithosphere and Hydrosphere

Hydrosphere

Atmosphere

Geosphere

Anthrosphere

Biosphere

Geochemical spheres

Natural (geological) processes

Fe

Mg

Si

Lithosphere: the source

Ca

REE

Aragonite

Xenotime

Lithosphere: the source

Hydrosphere: the ground playing

• Chemical character of elements

• Reactivity of primary minerals

• Amplitudes of rock-water interactions

Elemental mobility in the environment

Chemical character

of elements

Amplitudes of rock-water interactions

2H2O 4H+ +O2 + 4e

-

2H+ + 2e- H2

Eh

pH

0 2 4 6 8 10 12 14

log

ai

-8

-7

-6

-5

-4

-3

-2

6.35 10.33H2CO

3* HCO

3

-CO

3

2-

H+

OH-

Common pHrange in nature

pH

W/R ratio

Reactivity of primary minerals

Elements are released from rocks according to the solubility of minerals

Its occurs through hydration, protonation and leaching

Charge- and radius-

controlled element behaviour

The solid-liquid interface

a =z±

ri

Fe3+ ® [Ar]4s2 3d3

Electronic configuration-

controlled element behaviour

Inner-sphere surface

complex

Outer-sphere surface

complex

Elements released from soil interact with finest plant roots and are

transferred to the plant. During this process they go through the

The hydrosphere-biosphere interface

Hydrosphere-Biosphere interface

Nutrients exploited these mechanisms to migrate through cell

membranes

Metal migrations through cell membranes

The fate of metals in organisms

Are they

nutrients? YES

Involved in

metabolic

processes

NO

Accumulated in

scalp, bones and

organs (1)

How these elements are

accumulated in organisms?

Yes, I know!

1) Darrah et al. (2009) – Metallomics, 1, 479-488

Some clues from marsh turtles

Emys trinacris is a protected turtle marsh species living in natural oasis

in Central Mediterranean. Sometimes these oasis suffer for anthropic

pressures from surrounding farm areas

Emys takes a part along the trophic chain being exposed to the

environmental pressure

Studying specimens from differently anthropized areas we can evaluate

occurring effects on the composition of biological fluids and tissues

Lanthanides!

What elements can we investigate to

enhance this anthropic signature, if

occurring?

Why Lanthanides

Strictly remember local geochemical

background

Allow us to discriminate between the

latter and other signatures (i.e.

anthropization).

Their “geochemical behaviour” can be

recognised.

It is influenced by reactions

mechanisms during several natural

processes.

Their behaviour changes during their

migration among different geochemical

spheres.

39

Y

Chemistry: Lanthanides + Y = REE

[Xe]4fn 6s0 5d0

lq =dQ

dr

39Y

Different ionic radius and charge density Same external electronic configuration

[REEni ] =

[REEsamplei ]

[REEREFi ]

The normalised concentration

These represent the sequence of concentration

ratios between [REE] in sample and in a reference

material.

Normalised concentrations are not affected by the typical odd-even effect typical of atomic

abundances of elements as a consequence of the Oddo-Harkins rule. This data treatment

allows us to recognise REE geochemical “anomalies”. Normalised concentrations are

influenced by the Lanthanide contraction (in crystalline solids) and by Electronic

configuration (in aqueous media).

La

Pr

Ce*

Ce

Ce*=

2[Ce]n([La]n + [Pr]n)

1.E-03

1.E-02

1.E-01

1.E+00

Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Evaluation of REE-normalised patterns

Hewartz et al. (2013) – Geochim. Cosmochim. Acta 103, 161–183

La

Yb

æ

èçö

ø÷n

-La

Sm

æ

èçö

ø÷n

LREE MREE HREE

Although 4f electrons are not involved in chemical bonds the progressive filling of 4f shell

along the REE series changes the elemental properties, as shown by amplitudes of i values.

REE3+ + mLmn- Û [REEL][3-ḿ n);bi =

[REEL][3-m´n)

[REE3+]´[Ln-]m

Dissolved complexation

The changes due to the occupancy of 4f

orbital influence REE behaviour during

the scavenging:

DREE =[REEFeOOH

3+ ]

[REEaq3+ ]

REE(FeOOH ) « REE(aq)

Bau (1999) – Geochim. Cosmochim. Acta 63, 67–77

Authigenic precipitations

Tetrad effects The formation of an ion complex effect is

accompained by the suppression of inter-

elettronic repulsion typical of free ions. In REE

it depends on the occupancy of f-orbital

resulting variable along the REE series.

During an equilibrium of REE complexes

between aqueous (H2O) and organic (L-)

phases, changes in inter-elettronic repulsions

for each REE between the two complexes

produce a partition of this REE ion between

the two media producing the TETRAD

EFFECT.

REE3+

H2O

H2O

H2O

H2O

H2O

H2O H2O

H2O

REE3+

L-

L-

L-

L-

L-

L-

L-

L-

Tetrad Effects occur only if complexes are formed with an inner-sphere

mechanism and represent a proxy of reaction paths

Tetrad effects If equilibrium conditions involving REE species are

attained between two different media (i.e. aqueous-

organic phases), the succession of distribution

coefficients along the REE series can show typical

splitting the pattern into four curved segments called

“tetrads”. Sometimes these features can be found in

REE-normalised patterns or in stability constants of

REE-complexes.

REEorg REEaq

Tetrad 1 – La-Nd

Tetrad 2 – Pm-Gd

Tetrad 3 – Gd – Ho

Tetrad 4 – Er - Lu

Amplitudes of these tetrads can be

calculated according to the

relationship:

ti =[REE]2 ´ [REE]3[REE]1 ´ [REE]4

In samples less affected by

anthropogenic input REE contents

in blood increase with weight of the

investigated specimen.

In samples from highly anthropised

areas REE contents are not related

with the weight of studied item. At

least in these samples a slight

inverse relationship is observed.

REE in marsh turtles

Suggestions

High REE contents influence the turtle metabolism (Ogawa et al., 1994; 1995;

Renner et al., 2011)

In highly contaminated areas a limited food disposal occurs. The turtle growth

is inhibited (Tai et al., 2010)

Censi et al. (2013) – Chemosphere, 91, 1030-1035

In anthropized site REE contents in waters is higher. Blood concentrates REE from

ambient water. In un-anthropized site this effect is larger and occurs with different

features.

KD values in blood-water system depict a “bulge-shaped” pattern in more

contaminated site and a progressively increasing trend in less contaminated site.

REE partitioning between blood and water

0

5

10

15

20

25

0 5 10 15 20 25

[REE]anthropised site

[RE

E] u

n-a

nth

rop

ised

sit

e

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

104

103

105

104

anthropised site

un-anthropised site

KD

[RE

E] b

lood

[RE

E] w

ate

r

Significance of REE behaviour in blood

log

R

EE

(PO

4)

8

9

10

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Features of shale-normalized REE patterns in

blood from the contaminated site resemble the

REE fractionations in mother solutions of

inorganic REE phosphates (Byrne et al.,

1996).

Features of shale-normalized REE patterns in

blood from the uncontaminated site resemble

the sequence of stability REE constants for

REE(PO4) aqueous complexes (Johannesson

et al. 1996; Earth Plan. Sci. Lett. 139, 305-320)

Byrne et al. (1996) – Geochim. Cosmochim. Acta 60, 3341-3346

Significance of REE behaviour in scute

Reynard et al. (1999) – Chem. Geol. 155, 233-241

Features of shale-normalised REE patterns in scute samples agree with phosphate

crystallization both in contaninated and uncontaminated sites. But the larger REE contents

in contaminated site lead to the adsorption of REE excess onto phosphate surfaces

inducing a decrease of La/Sm ratios in these samples.

Geochemical application of REE features in scute

0.1

1.0

10.0

0.1 1.0

uncontaminated sitecontaminated site

La/Smn

La/

Yb

n

incr

easi

ng

sca

ven

gin

g

Hewartz et al. (2013) – Geochim. Cosmochim. Acta 103, 161-183

• Effects of environmental contaminations influence both concentrations and the

distribution of Rare Earths in blood of Emys trinacris marsh turtle

• Probably Rare Earths occur in blood as phosphate complexes or are bound to PO4

groups of biological molecules

• Crystallizing the turtle exoskeleton, blood acts similarly to the mother solution of

inorganic phosphates and REE occurring in blood are partitioned according to

their ELCOC characters

• In less contaminated environments Rare Earths co-precipitate with Ca2+ to form

phosphate. On the contrary, in highly contaminated areas the Rare Earths in

excess are also scavenged onto surfaces of biogenic phosphates

The Geochemical Behaviour of REE, a concept coming from forty years

of geochemical studies on these elements, represents an efficient concept

also to recognise reactions mechanisms during environmental reactions

involving biomineralizations and can be applied to environmental studies.

Conclusions