Spatial trends in the distribution of natural radioisotopes in the bottom sediments of Santos Basin (Brazil)


  • Paulo Alves de Lima Ferreira
  • Rubens Cesar Lopes Figueira
  • Michel Michaelovitch de Mahiques
  • Silvia Helena de Mello e Sousa


226RA;, 228RA, Gamma Spectrometry, Sources


Activities related to the marine exploration of oil and gas reservoirs tend to cause a concentration of natural radionuclides in related materials. As such, knowledge regarding the distribution of radionuclides in sedimentary basins with current oil operations is essential for modeling radiological hazards and possible risks of site contamination. This study investigated the distribution of 226Ra and 228Ra, radioisotopes from the 232U and 232Th decay chains in bottom sediment of the Santos basin. Sediment samples were collected from sites in a sampling grid based on depth contours and were analyzed through high-resolution gamma spectrometry. A distribution model of the spatial variation of these isotopes, the frst of its kind for the Basin, supported the interpretation of similar tendencies in their distribution. From studying the spatial trends of the mean levels of the isotopes with descriptive statistics and variance analysis, latitudinal and bathymetric diferences in the content of radionuclides emerged. These diferences are probably derived from the distinct sources of these elements, as 226Ra originates in the deep ocean from the decay of parent 230Th and from the patterns of sedimentation driven by open ocean circulation, while 228Ra is supplied by terrigenous materials transported by the northward-fowing Brazilian Coastal Current.


AHMAD, F., MORRIS, K., LAW, G. T. W., TAYLOR, K. G. & SHAW, S. 2021. Fate of radium on the discharge of oil and gas produced water to the marine environment. Chemosphere, 273, 129550.

ALZAHRANI, J. S., ALMUQRIN, A., ALGHAMDI, H., AL-BARZAN, B., KHANDAKER, M. U. & SAYYED, M. I. 2022. Radiological monitoring in some coastal regions of the Saudi Arabian Gulf close to the Iranian Bushehr nuclear plant. Marine Pollution Bulletin, 175, 113146.

ATWOOD, D. A. 2010. Radionuclides in the environment Chichester: John Wiley & Sons.

BROECKER, W. S., GODDARD, J. & SARMIENTO, J. L. 1976. The distribution of 226Ra in the Atlantic Ocean. Earth and Planetary Science Letters, 32(2), 220-235.

BRUHN, C. H. L., PINTO, A. C. C., JOHANN, P. R. S., BRANCO, C. C. M., SALOMÃO, M. C. & FREIRE, E. B. 2017. Campos and Santos Basins: 40 years of reservoir characterization and management of shallow- to ultra-deep water, post- and pre-salt reservoirs - historical overview and future challenges. In: Proceedings of the Ofshore Technology Conference (OTC) 2017 Rio de Janeiro, Brazil, 2017 Oct 24. Rio de Janeiro: OTC.

CHANG, H. K., KOWSMANN, A. M. F. & FIGUEIREDO A. B. 1992. Tectonics and stratigraphy of the East Brazil Rift system: an overview. Tectonophysics, 213(1-2), 97-138.

DAN, M. A. & EL SAMAN, M. I. 2014. The interactions of some radioelements activity patterns with some hydrographic parameters at the petroleum and phosphate regions in the Red Sea, Egypt. Journal of Radiation Research and Applied Sciences, 7(3), 292-7(3), 292-304.

DE MAHIQUES, M. M., TASSINARI, C. C., MARCOLINI, S., VIOLANTE, R. A., FIGUEIRA, R. C., SILVEIRA, I. C. & SOUSA, S. H. 2008. Nd and Pb isotope signatures on the Southeastern South American upper margin: implications or sediment transport and source rocks. Marine Geology, 250, 51-63.

DE MAHIQUES, M. M., TESSLER, M. G., CIOTTI, A. M., SILVEIRA, I. C., SOUSA, S. H., FIGUEIRA, R. C. & PASSOS, R. F. 2004. Hydrodynamically driven patterns of recent sedimentation in the shelf and upper slope of Southeast Brazil. Continental Shelf Research, 24, 1685-1697.

DOWDALL, M. & LEPLAND, A. 2012. Elevated levels of radium-226 and radium-228 in marine sediments of the Norwegian Trench (“Norskrenna”) and Skagerrak. Marine Pollution Bulletin, 64(10), 2069-2076.

EL-REEFY, H. I., BADRAN, H. M., SHARSHAR, T., HILAL, M. A. & ELNIMR, T. 2014. Factors afecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake. Journal of Environmental Radioactivity, 134, 35-42.

EYROLLE, F., RADAKOVITCH, O., RAIMBAULT, P., CHARMASSON, S., ANTONELLI, C., FERRAND, E., AUBERT, D., RACCASI, G., JACQUET, S. & GURRIARAN, R. 2012. Consequences of hydrological events on the delivery of suspended sediment and associated radio-nuclides from the Rhône River to the Mediterranean Sea. Journal of Soils and Sediments, 12(9), 1479-1495.

FARIA, D. L. P., REIS, A. T. & SOUZA JUNIOR, O. G. 2017. Three-dimensional stratigraphic-sedimentological forward modeling of an Aptian carbonate reservoir deposited during the sag stage in the Santos basin, Brazil. Marine and Petroleum Geology, 88, 676-695.

FERREIRA, P. A. L., FIGUEIRA, R. C. L., CAZZOLI Y GOYA, S. & DE MAHIQUES, M. M. 2020. Insights on the marine sedimentation of the continental shelf and upper slope of SE Brazil during the 20th century with natural radionuclides. Regional Studies in Marine Sciences, 39, 101466.

FERREIRA, P. A. L., SIEGLE, E., SCHETTINI, C. A. F., MAHIQUES, M. M. & FIGUEIRA, R. C. L. 2014. Statistical validation of the model of difusion-convection (MDC) of 137Cs for the assessment of recent sedimentation rates in coastal systems. Journal of Radioanalytical and Nuclear Chemistry, 303, 2059-2071.

FISHER, R. S. 1998. Geologic and geochemical controls on naturally occurring radioactive materials (NORM) in produced water from oil, gas, and geothermal operations. AAPG Division of Environmental Geosciences Journal, 5(3), 139-150.

FREITAS, V. A., VITAL, J. C. S., RODRIGUES, B. R. & RODRIGUES, R. 2022. Source rock potential, main depocenters, and CO2 occurrence in the pre-salt section of Santos Basin, southeast Brazil. Journal of South American Earth Sciences, 115, 103760.

HILAL, M. A., ATTALLAH, M. F., MOHAMED, G. Y. & FAYEZ-HASSAN, M. 2014. Evaluation of radiation hazard potential of TENORM waste from oil and natural gas production. Journal of Environmental Radioactivity, 136, 121-126.

KAPPA, F. K., TSABARIS, C., PATIRIS, D. L., ANDROULAKAKI, E. G., ELEFTHERIOU, G., BETSOU, C., MICHALOPOULOU, V., KOKKORIS, M. & VLASTOU, R. 2018. Historical trends and assessment of radionuclides and heavy metals in sediments near an abandoned mine, Lavrio, Greece. Environmental Science and Pollution Research, 25(30), 30084-30100.

KWON, E. Y., KIM, G., PRIMEAU, F., MOORE, W. S., CHO, H. M., DEVRIES, T., SARMIENTO, J. L., CHARETTE, M. A. & CHO, Y. K. 2014. Global estimate of submarine groundwater discharge based on an observationally constrained radium isotope model. Geophysical Research Letters, 41(23), 8438-8444.

LAUER, N. & VENGOSH, A. 2016. Age dating oil and gas wastewater spills using radium isotopes and their decay products in impacted soil and sediment. Environmental Science & Technology Letters, 3(5), 205-209.

LE ROY, E., SANIAL, V., CHARETTE, M. A., VAN BEEK, P., LACAN, F., JACQUET, S. H. M., HENDERSON, P. B., SOUHAUT, M., GARCÍA-IBÁÑEZ, M. I., JEANDEL, C., PÉREZ, F. F. & SARTHOU, G. 2018. The 226Ra-Ba relationship in the North Atlantic during GEOTRACES-GA01. Biogeosciences, 15(9), 3027-3048.

LIGERO, R. A., RAMOS-LERATE, I., BARRERA, M. & CASAS-RUIZ, M. 2001. Relationships between sea-bed radionuclide activities and some sedimentological variables. Journal of Environmental Radioactivity, 57(1), 7-19.

LIN, W., FENG, Y., YU, W., LAN, W., WANG, Y., MO, Z., NING, Q., FENG, L., HE, X. & HUANG, Y. 2020. Long-lived radionuclides in marine sediments from the Beibu Gulf, South China Sea: spatial distribution, controlling factors, and proxy for transport pathway. Marine Geology, 424, 106157.

LU, Z. T., SCHLOSSER, P., SMETHIE JUNIOR, W. M., STURCHIO, N. C., FISCHER, T. P., KENNEDY, B. M., PURTSCHERT, R., SEVERINGHAUS, J. P., SOLOMON, D. K., TANHUA, T. & YOKOCHI, R. 2014. Tracer applications of noble gas radionuclides in the geosciences. Earth-Science Reviews, 138, 196-214.

MATISOFF, G. 2014. 210Pb as a tracer of soil erosion, sediment source area identification and particle transport in the terrestrial environment. Journal of Environmental Radioactivity, 138, 343-354.

MOLLER JUNIOR, O. O., PIOLA, A. R., FREITAS, A. C. & CAMPOS, E. J. 2008. The efects of river discharge and seasonal winds on the shelf of southeastern South America. Continental Shelf Research, 28(13), 1607-1624.

MOORE, W. S., SARMIENTO, J. L. & KEY, R. M. 2008. Submarine groundwater discharge revealed by 228Ra distribution in the upper Atlantic Ocean. Nature Geoscience, 1, 309-311.

MOREIRA, J. L. P., MADEIRA, C. V., GIL, J. A. & MACHADO, M. A. P. 2007. Bacia de Santos. Boletim de Geociências da Petrobrás, 15(2), 531-549.

NABHANI, K. A. L., KHAN, F. & YANG, M. 2016. The importance of public participation in legislation of TENORM risk management in the oil and gas industry. Process Safety and Environmental Protection, 102, 606-614.

NABHANI, K. A. L., KHAN, F. & YANG, M. 2017. Dynamic modeling of TENORM exposure risk during drilling and production. Journal of Petroleum Exploration and Production Technology, 8(1), 175-188.

NAGAI, R. H., FERREIRA, P. A. L., MULKHERJEE, S., MARTINS, M. V., FIGUEIRA, R. C. L., SOUSA, S. H. M. & DE MAHIQUES, M. M. 2014. Hydrodynamic controls on the distribution of surface sediments from the southeast South American continental shelf between 23°S and 38°S. Continental Shelf Research, 89, 51-60.

PARRY, L. E., CHARMAN, D. J. & BLAKE, W. H. 2013. Comparative dating of recent peat deposits using natural and anthropogenic fallout radionuclides and Spheroidal Carbonaceous Particles (SCPs) at a local and landscape scale. Quaternary Geochronology, 15, 11-19.

PATIRIS, D. L., TSABARIS, C., ANAGNOSTOU, C. L., ANDROULAKAKI, E. G., PAPPA, F. K., ELEFTHERIOU, G. & SGOUROS, G. 2016. Activity concentration and spatial distribution of radionuclides in marine sediments close to the estuary of Shatt al-Arab/Arvand Rud River, the Gulf. Journal of Environmental Radioactivity, 157, 1-15.

PEREIRA, M. J. & MACEDO, J. M. 1990. A Bacia de Santos: perspectivas de uma nova província petrolífera na plataforma continental sudeste brasileira. Boletim de Geociências da Petrobrás, 4(1), 3-11.

PERIÁÑEZ, R. 2020. Models for predicting the transport of radionuclides in the Red Sea. Journal of Environmental Radioactivity, 223-224, 106396.

POINSSOT, C. 2012. Overview of radionuclide behaviour in the natural environment. In: POINSSOT, C. & GECKEIS, H. (eds.). Radionuclide behaviour in the natural environment: science, implications and lessons for the nuclear industry. Oxford: Woodhead Publishing, pp. 1-10.

RAHMAN, R. O. A., ELMESAWY, M., ASHOUR, I. & HUNG, Y. T. 2013. Remediation of NORM and TENORM contaminated sites—review article. Environmental Progress & Sustainable Energy, 33(2), 588-596.

RODRÍGUEZ, C. R., JACKSON, C. A. L., ROTEVATN, A. & FRANCIS, M. 2018. Dual tectonic-climatic controls on salt giant deposition in the Santos Basin, ofshore Brazil. Geosphere, 14(1), 215-242.

UDDIN, S. & BEHBEHANI, M. 2018. Concentrations of selected radionuclides and their spatial distribution in marine sediments from the northwestern Gulf, Kuwait. Marine Pollution Bulletin, 127, 73-81.

VALAN, I. I., VIJAYALAKSHMI, I., MATHIYARASU, R., SRIDHAR, S. G. D., NARAYANAN, V. & STEPHEN, A. 2017. Infuence of geochemical variation and heavy mineral component on primordial radionuclide presence in Tamiraparani River sediments. Environmental Earth Sciences, 76(2), 69.

XU, B., LI, S., BURNETT, W. C., ZHAO, S., SANTOS, I. R., LIAN, E., CHEN, X. & YU, Z. 2022. Radium-226 in the global ocean as a tracer of thermohaline circulation: synthesizing half a century of observations. Earth-Science Reviews, 226(2), 103956.

YAKOVLEV, E. & PUCHKOV, A. 2020. Assessment of current natural and anthropogenic radionuclide activity concentrations in the bottom sediments from the Barents Sea. Marine Pollution Bulletin, 160, 111571.

ZIELINSKI, K. 2017. Sources, transport and sinks of radionuclides in marine environments. In: ZIELINSKI, K., SAGAN, I. & SUROSZ, W. (eds.). Interdisciplinary approaches for sustainable development goals Cham: Springer, pp. 189-202.




How to Cite

Ferreira, P. A. de L. ., Figueira, R. C. L. ., Mahiques, M. M. de, & Sousa, S. H. de M. e . (2023). Spatial trends in the distribution of natural radioisotopes in the bottom sediments of Santos Basin (Brazil). Ocean and Coastal Research, 71(Supl. 3). Retrieved from