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Case study: Historical trend in heavy metal pollution in the sediments of Cienfuegos Bay (Cuba),

IAEA Regional Training Course on Sediment Core Dating Techniques. RAF7/008 Project Rabat, 5 – 9 July 2010. Case study: Historical trend in heavy metal pollution in the sediments of Cienfuegos Bay (Cuba), defined by 210 Pb and 137 Cs geochronology.

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Case study: Historical trend in heavy metal pollution in the sediments of Cienfuegos Bay (Cuba),

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  1. IAEA Regional Training Course on Sediment Core Dating Techniques. RAF7/008 Project Rabat, 5 – 9 July 2010 Case study: Historical trend in heavy metal pollution in the sediments of Cienfuegos Bay (Cuba), defined by 210Pb and 137Cs geochronology C. ALONSO HERNANDEZa , S. PEREZ SANTANAa, C. BRUNORIb, R. MORABITOc, R. DELFANTId, C.PAPUCCId CEAC - Cuba , ENEA - Italy

  2. Objectives • Mechanismscontrollingpollutantdistribution in Cienfuegos Bay: • geochronologybased on natural and • anthropogenicradionuclides • identificationofmainsedimentological • processes • heavy metal (V, Ni, As) horizontal and • verticaldistributions • reconstructionofpollutionhistory

  3. The study area

  4. Studyarea andsamplingpoints Sampling Methods Surficial sediments: Petersen grab Cores: 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-background intrinsic germanium detectors. Heavy metals (V,Ni,Cr,As) by ICP-MS. Campaigns: 1999, 2000, 2001 Sedimentcores

  5. Geochronology – 137Cs Core North Core South

  6. 1963 1963 Geochronology – 137Cs Core South Core North

  7. 100 ) d.w. -1 Bq kg 10 ( Pb-210ex 210Pb profiles indicate: • regular sediment accumulation up to early sixties • North 0.3 g cm-2 y-1 South 0.4 g cm-2 y-1 1 Geochronology – 210Pb Core North Core South 1969 1988 1963 1963 • irregular sediment deposition afterwards.

  8. Processes Important change in land uses after 1958 • enhanced particle supply • irregular sedimentation • changes in the hydrological regime Sediments accumulated regularly from 1900 to around 1960

  9. Aug, 1969 Intense winds Flood, Sediments re-suspension from estuaries and transport to the bay. New 137Cs max in bay sediments HurricaneCamille, 1969

  10. 100 ) d.w. -1 Bq kg 10 ( Pb-210ex 1 Geochronology – 210Pb Core North Core South 1969 1969 1988 1963 1963 The intermediate peak in 137Cs concentration can then be dated to 1969, consequence of hurricane Camille.

  11. Another episode able to re-suspend significant amounts of estuarine sediments s intense rain in 1988: 1000 mm in 7 days Rainintensity

  12. 100 ) d.w. -1 Bq kg 10 ( Pb-210ex 1 Geochronology – 210Pb Core North Core South 1969 1969 1988 1963 1988 1963 The most recent peak in 137Cs profiles is attributed to sediment re-suspension rom estuaries and transport to the bay Following intense rain episode in 1988.

  13. Heavy 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)

  14. Salado river Damuji river Cienfuegos City S15 22°07´ Caonao river N2 C1 S18 Caribbean Sea Arimao river 0 3 Km 80°29´ Vanadiumhorizontaldistribution N6 N5 N8 N7 N9 Thermoelectric power plant N10 N4 400 N11 N12 N13 N3 N14 350 300 250 N16 200 N17 150 100 50 0

  15. Salado river N5 N6 Damuji river N7 N8 N9 Thermoelectric power plant N10 N4 Cienfuegos City N11 120 N12 N13 N3 105 N14 S15 90 22°07´ Caonao river N2 75 S16 60 S17 C1 45 S18 30 Caribbean Sea Arimao river 15 80°29´ 0 3 Km 0 Nickelhorizontaldistribution

  16. Total V (mg/kg) Total Ni (mg/kg) 1963 1963 Vanadium and Nickel: The influenceof the powerplant Core North Core South

  17. 1988 1963 Arsenicverticalprofiles: the influenceof the FertilizerFactory Core North Core South

  18. Conclusions Radionuclides profiles essential tool to identify processes and environmental changes - Airborne pollutants, (V and Ni) distributed in the whole Bay. Highest concentrations close to the thermoelectric power plant. Significant increase in conc. In the ’60s, corresponding to enhanced power output. • As (directly discharged into the sea) is confined in • Northern basin: fertiliser industry as point source. • Major contribution in 1980: first (undeclared) accident.

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