1. “To predict the future of coastal areas is necesary to know how was it in past”

2. One century sedimentary record of Hg and Pb pollution in the Sagua estuary (Cuba) derived from 210 Pb and 137 Cs chronology Díaz-Asencio M. Alonso-Hernández C.M., Bolanos- Álvarez Y., Gómez-Batista M., Morabito R., Hernández- Albernas J.I., Eriksson M., Sanchez-Cabeza J.A. Díaz-Asencio M. Alonso-Hernández C.M., Bolanos- Álvarez Y., Gómez-Batista M., Morabito R., Hernández- Albernas J.I., Eriksson M., Sanchez-Cabeza J.A. Centro de Estudio Ambientales de Cienfuegos, Cienfuegos, Cuba. Centro de Estudio Ambientales de Cienfuegos, Cienfuegos, Cuba. ENEA-C.R.E. Casaccia, PROT-CHIM, Roma, Italy. ENEA-C.R.E. Casaccia, PROT-CHIM, Roma, Italy. Centro de Investigaciones y Servicios Ambientales, Villa Clara, Cuba. Centro de Investigaciones y Servicios Ambientales, Villa Clara, Cuba. IAEA Marine Environment Laboratories, Monaco. IAEA Marine Environment Laboratories, Monaco.

3. Hg Hg Pb Chlor-alkali plant Urban waste Pollution sources Pollution sources Dum 1972 Alacranes Dam

4. Hg 1979 Chlor-alkali plant Mercury cell

5. Sagua la grande city

6. Sampling Bahía de Santa Clara (15 m)

7. High-resolution gamma spectrometry Mercury analysis X-Ray Fluorescence (XRF) SPECTOR X-LAB PRO 2000 system SRMCertified Hg (µg g -1 ) Measured Hg (µg g -1 ) PACS-14.57 ± 0.165.15 ± 0.17 BEST-10.092 ± 0.0090.11 ± 0.03 SRM 16451.1 ± 0.51.06 ± 0.14 Grain size

8. 210 Pb Accumulation rate: 0.17 ± 0.04 g cm -2 y -1 (0.52 ± 0.13 cm y -1 ) 137 Cs Accumulation rate 0.18 ± 0.07 g cm-2 y -1 (0.52 ± 0.09 cm y -1 )

9. Alacranes Dam Dum 1972

10. Hg and Pb profiles

11. Pb (µg.g -1 ) Pb pollution Based on Enrichment Factor (EF) : EF=(M s /Al s )/(M b /Al b ) where M and Al represent the trace metal and aluminium concentrations, respectively; and, the subscripts s and b refer to sample and background values. This period coincides with a strong economic contraction in Cuba

12. 1988 Total Hg (µg g -1 ) The sediment quality of Sagua la Grande estuary suggests the presence of a significant contamination Hg (ppm)

13. Conclusions The observed sedimentation rate was 0.171 ± 0.04 g cm-2 year-1, corresponding to a sediment accumulation rate of 0.52 ± 0.13 cm year-1. The 137 Cs profile corroborated these estimates. The observed sedimentation rate was 0.171 ± 0.04 g cm-2 year-1, corresponding to a sediment accumulation rate of 0.52 ± 0.13 cm year-1. The 137 Cs profile corroborated these estimates. The Hg (concentrations up to 2.7 µg g-1) and Pb (concentrations up to 22 µg g-1) depth profiles showed important anthropogenic inputs to the coastal environment. The incomplete treatment of the residual from the chlor-alkali plant and the increment of Sagua la Grande city population are the main human activities that determine the time evolution of Hg and Pb in these sediments. The Hg (concentrations up to 2.7 µg g-1) and Pb (concentrations up to 22 µg g-1) depth profiles showed important anthropogenic inputs to the coastal environment. The incomplete treatment of the residual from the chlor-alkali plant and the increment of Sagua la Grande city population are the main human activities that determine the time evolution of Hg and Pb in these sediments. The observed Pb fluxes to sediments may reflect the overall development of Cuba. While industrial and economical expansion was continuous in the 1920-1980 period, a certain economical contraction was observed in the 90s, in good agreement with the collapse of the soviet economy and the commercial embargo to the country. The observed Pb fluxes to sediments may reflect the overall development of Cuba. While industrial and economical expansion was continuous in the 1920-1980 period, a certain economical contraction was observed in the 90s, in good agreement with the collapse of the soviet economy and the commercial embargo to the country. The present study showed high mercury contamination in sediments of Sagua la Grande estuary. Further studies on the uptake and distribution of Hg in edible organisms will be necessary for evaluating the risk for the local populations. The present study showed high mercury contamination in sediments of Sagua la Grande estuary. Further studies on the uptake and distribution of Hg in edible organisms will be necessary for evaluating the risk for the local populations.

14. Thanks