Case study:Case study:Historical trend in heavy metal pollution Historical trend in heavy metal pollution

in the sediments of Cienfuegos Bay (Cuba), in the sediments of Cienfuegos Bay (Cuba), defined by defined by 210210Pb and Pb and 137137Cs geochronologyCs geochronology

C. ALONSO HERNANDEZa , S. PEREZ SANTANAa, C. BRUNORIb, R. MORABITOc, R. DELFANTId, C.PAPUCCId

CEAC - Cuba , ENEA - Italy

IAEA Regional Training Course on Sediment Core Dating Techniques. IAEA Regional Training Course on Sediment Core Dating Techniques. RAF7/008 ProjectRAF7/008 Project

Rabat, 5 – 9 July 2010Rabat, 5 – 9 July 2010

11

Mechanisms controlling pollutant distribution in Mechanisms controlling pollutant distribution in Cienfuegos Bay:Cienfuegos Bay:

geochronology based on natural andgeochronology based on natural and anthropogenic radionuclidesanthropogenic radionuclidesidentification of main sedimentologicalidentification of main sedimentological processes processes heavy metal (V, Ni, As) horizontal and heavy metal (V, Ni, As) horizontal and vertical distributionsvertical distributionsreconstruction of pollution historyreconstruction of pollution history

ObjectivesObjectives

22

The study areaThe study area

33

StudyStudy area andarea and samplingsampling pointspoints

Sampling Methods

Surficial sediments: Petersen grabCores: scuba-driven plastic tube, 10cm in Ø.Immediately sliced with 1-cm resol. Sub-samples preserved deep-frozen.

Analytical methods

Radionuclides (210Pb, 226Ra, 137Cs)by - spectrometry, using low-backgroundintrinsic germanium detectors.

Heavy metals (V,Ni,Cr,As) by ICP-MS.

44

Sediment cores

Campaigns:1999, 2000, 2001

Geochronology – Geochronology – 137137CsCs

Core North

5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

Core South

0 5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs

-137

(B

q k

g-1

d.w

.)

Mass Depth (g cm-2)

55

Core North

5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

Core South

0 5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs

-13

7 (

Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

1963

1963

66

Geochronology – Geochronology – 137137CsCs

0 5 10 15 20 25 30 35

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

0 5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

Geochronology – Geochronology – 210210PbPb

19

63

Core North Core South

19

63

19

69

19

88

• regular sediment accumulation up to early sixties North 0.3 g cm-2 y-1 South 0.4 g cm-2 y-1

210Pb profiles indicate:

• irregular sediment deposition afterwards.

77

1

10

100

Pb

-21

0e

x (

Bq

kg

-1 d

.w.)

1

10

100

Pb

-210

ex ( B

q k

g-1 d

.w.)

Important change in land uses after 1958

• enhanced particle supply• irregular sedimentation • changes in the hydrological regime

ProcessesProcesses

Sediments accumulated regularly from 1900 to around 1960

88

99

Intense windsFlood,Sedimentsre-suspensionfrom estuariesand transport to the bay.

New 137Cs maxin bay sediments

Aug, 1969

Hurricane Camille, 1969Hurricane Camille, 1969

0 5 10 15 20 25 30 35

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

0 5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

Geochronology – Geochronology – 210210PbPb

19

63

Core North Core South

19

63

19

69

19

88

1010

1

10

100

Pb

-21

0e

x (

Bq

kg

-1 d

.w.)

1

10

100

Pb

-210

ex ( B

q k

g-1 d

.w.)

1969

The intermediate peak in 137Cs concentration can then be dated to 1969,

consequence of hurricane Camille.

1111

Another episodeable to re-suspend significant amounts of estuarine sediments s intense rain in 1988:1000 mm in 7 days

Rain intensityRain intensity

0 5 10 15 20 25 30 35

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

0 5 10 15 20 25 30 350

2

4

6

8

10

12

14

16

18

20

Cs-

137

(Bq

kg

-1 d

.w.)

Mass Depth (g cm-2)

19

63

19

69

19

88

Geochronology – Geochronology – 210210PbPb

Core North Core South

19

63

19

69

19

88

1212

1

10

100

Pb

-21

0e

x (

Bq

kg

-1 d

.w.)

1

10

100

Pb

-210

ex ( B

q k

g-1 d

.w.)

The most recent peak in 137Cs profiles is attributed to sedimentre-suspension rom estuaries and transport to the bay

Following intense rain episode in 1988.

1313

Heavy metal pollution in the bayHeavy metal pollution in the bay

Spatial and vertical distribution of heavy metals from:

thermoelectric power plant (Ni, V - athmospheric input);

fertilizer industry (As - liquid discharge)

VanadiumVanadium horizontal distribution horizontal distribution

0

50

100

150

200

250

300

350

400

N3

N4

N5 N6N7 N8

N9

N10

N12N13

N14

N11

N16

N17

Thermoelectric power plant

80°29´

22°07´

Caribbean Sea

0 3 Km

Cienfuegos City

Salado riverDamuji river

Caonao river

Arimao river

N2

C1

S18

S15

1414

NickelNickel horizontal distributionhorizontal distribution

80°29´

22°07´

Caribbean Sea

0 3 Km

Cienfuegos City

Salado riverDamuji river

N2

C1

0

15

30

45

60

75

90

105

120

N3

N4

N5 N6N7 N8

N9

N10

N12N13

N14

S15

N11

S16

S17

S18

Thermoelectric power plant

Arimao river

Caonao river

1515

35

30

25

20

15

10

5

00 20 40 60 80 100 120 1400 20 40 60 80 100 120 140

Mas

s de

pth

(g c

m-2

)

35

30

25

20

15

10

5

00 20 40 60 80 100 120 1400 20 40 60 80 100 120 140

Mas

s de

pth

(g c

m-2

)

Total V (mg/kg)

Core North Core South

Total Ni (mg/kg)

VanadiumVanadium and and Nickel:Nickel:The influence of the power plantThe influence of the power plant

1963

1963

1616

0

5

10

15

20

25

30

35

0 20 40 60 80 1000 10 20 30 40 50 60 70 80 90 100

Mas

s de

pth

(g c

m-2

)

0

5

10

15

20

25

30

35

0 20 40 60 80 1000 10 20 30 40 50 60 70 80 90 100

Mas

s de

pth

( g

cm-2

)

1988

1963

ArsenicArsenic vertical profiles: vertical profiles:the influence of the Fertilizer Factorythe influence of the Fertilizer Factory

Core North Core South

1717

ConclusionsConclusions

- - Airborne pollutants, (V and Ni) distributed Airborne pollutants, (V and Ni) distributed in the whole Bay. Highest concentrations close in the whole Bay. Highest concentrations close to the thermoelectric power plant. to the thermoelectric power plant. Significant increase in conc. In the ’60s, Significant increase in conc. In the ’60s, corresponding to enhanced power output.corresponding to enhanced power output.

- As (directly discharged into the sea) is confined in As (directly discharged into the sea) is confined in Northern basin: fertiliser industry as point source.Northern basin: fertiliser industry as point source. Major contribution in 1980: first (undeclared) accidentMajor contribution in 1980: first (undeclared) accident.

Radionuclides profiles essential tool to identifyRadionuclides profiles essential tool to identifyprocesses and environmental changesprocesses and environmental changes

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