Alonso-Hernández, C. M. (Carlos Manuel)
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- Pollution monitoring in two urban areas of Cuba by using Tillandsia recurvata (L.) L. and top soil samples: spatial distribution and sources(2021) Viera-Ribot, O. (Orlando); Alejo, D. (Daniellys); Lasheras, E. (Esther); Morales, M.C. (Mayra C.); Santamaria-Ulecia, J.M. (Jesús Miguel); Elustondo, D. (David); Morera-Gómez, Y. (Yasser); Alonso-Hernández, C. M. (Carlos Manuel); Armas-Camejo, A. (Alejandro)This work provides a comprehensive report on the chemical composition of 47 major and trace elements in Tillandsia recurvata (L.) L. and top soil samples from the cities of Cienfuegos and Santa Clara in Cuba. The main aims were to provide new information on the urban pollution degree in Caribbean urban regions where the availability of data of urban health indicators are very limited and to identify the main pollution sources. The abundance of the analyzed elements at both type of samples were different at each urban regions suggesting the influence of various sources. Top soils were slightly contaminated with Zn, V, Ba, Pb, Ni, Cr, Cu, Co and Hg and seriously contaminated with Ni and Cr in Santa Clara. These and other elements such as Se, S, P, Cd, Mo and Ca where highly enriched in T. recurvata indicating a significant impact of anthropogenic sources in the air quality of both urban areas. Cluster analysis helped us associate most of the elements with an anthropogenic origin with three main pollution sources: road traffic, industrial emissions and oil combustion. The spatial variability was particularly useful to identify some of these sources including the emissions from diesel and fuel oil combustion in power stations, biomass burning and metallurgic industries. The results also showed that V and Ni were strongly associated to the oil combustion and that V/Ni ratio indices in both indicators can be used to trace this type of sources. The results presented in this study confirmed the conclusion that both T. recurvata and top soils can be used as feasible indicators of the health of Caribbean urban ecosystems and the distribution of the main pollution sources that are affecting them.
- Tracing organic matter sources in a tropical lagoon of the Caribbean Sea(Elsevier, 2017) Corcho-Alvarado, J.A. (Jose Antonio); Diaz-Asencio, M. (Misael); Garcia-Moya, A. (Alejandro); Tolosa, I. (Imma); Morera-Gómez, Y. (Yasser); Fanelli, E. (Emanuela); Alonso-Hernández, C. M. (Carlos Manuel)The natural protected lagoon of Guanaroca, located between Cienfuegos Bay and the Arimao River, Cuba, has been heavily impacted by human-induced environmental changes over the past century. Sources of organic matter in the Guanaroca lagoon and concentrations of radioisotopes (210Pb, 226Ra, 137Cs and 239,240Pu), as tracers of anthropogenic impacts, were investigated in a 78 cm sediment core. Variations in total organic carbon (TOC), total nitrogen (TN), stable isotopic composition (δ13C and δ15N) and ratio of total organic carbon to total nitrogen (C/N) were analysed. On such a basis, environmental changes in the lagoon were revealed. Down core variation patterns of the parameters representing sources of organic matter were predominantly related to the impacts of human activities. Up to the nineteenth century, the principal sources of organic matter to sediments (more than 80%) were a mixing of terrestrial vascular plants (~48%) and freshwater phytoplankton (~8%), with minimal contribution from the marine component (~16%). In the period 1900–1980, due to the strong influence of human activities in the catchment area, the water exchange capacity of the lagoon declined substantially, as indicated by the relatively high proportion of organic matter originated from human activities (58%). Since 1980, as a result of management actions in the protected area, the lagoon has regained gradually its capability to exchange freshwater, showing sources of organic matter similar to the natural conditions recorded previous to 1900, although an indication of human impact (treated sewage contributed for 26% to the organic matter in sediments) was still observed and further management measures would be required.
- Observations of fallout from the Fukushima reactor accident in Cienfuegos, Cuba(2011) Cartas-Aguila, H.A. (Héctor A.); Diaz-Asencio, M. (Misael); Guillén-Arruebarruena, A. (Aniel); Morera-Gómez, Y. (Yasser); Alonso-Hernández, C. M. (Carlos Manuel)Following the recent accident at the Fukushima Daiichi nuclear power plant in Japan, radioactive contamination was observed near the reactor site. As a contribution towards the understanding of the worldwide impact of the accident, we collected fallout samples in Cienfuegos, Cuba, and examined them for the presence of above normal amounts of radioactivity. Gamma ray spectra measured from these samples showed clear evidence of fission products (131)I and (137)Cs. However, the fallout levels measured for these isotopes (135 ± 4.78 mBq m(-2) day(-1) for (131)I and 10.7 ± 0.38 mBq m(-2) day(-1)for (137)Cs) were very low and posed no health risk to the public. The doses received as consequence to the Fukushima fallout by the Cienfuegos population's (0.002 mSv per year) don't overcome the limit of dose (1 mSv per year) fixed for the public in Cuba.
- Terrestrial gamma radiation dose rate in Cienfuegos, Cuba(2016) Cartas-Aguila, H.A. (Héctor A.); Diaz-Asencio, M. (Misael); Muñoz-Caravaca, A. (A.); Acosta-Milián, R. (R.); Sánchez-Llul, M. (M.); Morera-Gómez, Y. (Yasser); Alonso-Hernández, C. M. (Carlos Manuel)This study assesses the level of background radiation for Cienfuegos Province, Cuba. Measurements of outdoor gamma radiation (of terrestrial and cosmic origin) in air were performed at 198 locations using a GPS navigator and a dose meter (SRP-68-01, 30 × 25 mm NaI detector). The average absorbed dose was found to be 73.9 nGy h-1 (17.2–293.9 nGy h-1), corresponding to an annual effective dose of 74.7 μSv (21–324 μSv). When compared with the data available for other places, the absorbed gamma doses obtained in this study indicate a background radiation level that falls within natural limits for the Damuji, Salado and Caonao watersheds; however, the Arimao and Gavilanes watersheds present levels of the absorbed dose and annual effective dose comparable with high background radiation areas. An isodose map of the terrestrial gamma dose rate in Cienfuegos was drawn using the GIS application “Arc View”. This study provides important baseline data of radiation exposure in the area.
- Atmospheric deposition patterns of 210Pb and 7 Be in Cienfuegos, Cuba(Elsevier, 2014) Cartas-Aguila, H.A. (Héctor A.); Guillén-Arruebarrena, A. (Aniel); Morera-Gómez, Y. (Yasser); Alonso-Hernández, C. M. (Carlos Manuel)The radiometric composition of bulk deposition samples, collected monthly for one year, February 2010 until January 2011, at a site located in Cienfuegos (22 030 N, 80 290 W) (Cuba), are analysed in this paper. Measurement of 7 Be and 210Pb activity concentrations were carried out in 12 bulk deposition samples. The atmospheric deposition fluxes of 7 Be and 210Pb are in the range of 13.2e132 and 1.24e8.29 Bq m2 , and their mean values are: 56.6 and 3.97 Bq m2 , respectively. The time variations of the different radionuclide have been discussed in relation with meteorological factors and the mean values have been compared to those published in recent literature from other sites located at different latitudes. The annual average flux of 210Pb and 7 Be were 47 and 700 Bq m2 y1 , respectively. Observed seasonal variations of deposition data are explained in terms of different environmental features. The atmospheric deposition fluxes of 7 Be and 210Pb were moderately well correlated with precipitation and well correlated with one another. The 210Pb/7 Be ratios in the monthly depositions samples varied in the range of 0.05 e0.10 and showed a strong correlation with the number of rainy days
- Application of the Monte Carlo efficiency transfer method to an HPGe detector with the purpose of environmental samples measurement(Elsevier, 2015) Cartas-Aguila, H.A. (Héctor A.); Bernal-Castillo, J.L. (José L.); Guillén-Arruebarrena, A. (Aniel); Morera-Gómez, Y. (Yasser); Alonso-Hernández, C. M. (Carlos Manuel)Monte Carlo efficiency transfer method was used to determine the full energy peak efficiency of a coaxial n-type HPGe detector. The efficiencies calibration curves for three Certificate Reference Materials were determined by efficiency transfer using a 152Eu reference source. The efficiency values obtained after efficiency transfer were used to calculate the activity concentration of the radionuclides detected in the three materials, which were measured in a low-background gamma spectrometry system. Reported and calculated activity concentration show a good agreement with mean deviations of 5%, which is satisfactory for environmental samples measurement.
- Validation of an efficiency calibration procedure for a coaxial n-type and a well-type HPGe detector used for the measurement of environmental radioactivity(Elsevier, 2016) Cartas-Aguila, H.A. (Héctor A.); Morera-Gómez, Y. (Yasser); Nuñez-Duartes, C. (Carlos); Alonso-Hernández, C. M. (Carlos Manuel)To obtain reliable measurements of the environmental radionuclide activity using HPGe (High Purity Germanium) detectors, the knowledge of the absolute peak efficiency is required. This work presents a practical procedure for efficiency calibration of a coaxial n-type and a well-type HPGe detector using experimental and Monte Carlo simulations methods. The method was performed in an energy range from 40 to 1460 keV and it can be used for both, solid and liquid environmental samples. The calibration was initially verified measuring several reference materials provided by the IAEA (International Atomic Energy Agency). Finally, through the participation in two Proficiency Tests organized by IAEA for the members of the ALMERA network (Analytical Laboratories for the Measurement of Environmental Radioactivity) the validity of the developed procedure was confirmed. The validation also showed that measurement of 226Ra should be conducted using coaxial n-type HPGe detector in order to minimize the true coincidence summing effect.
- Naturally occurring radioactive materials (NORM) in ashes from a fuel-oil power plant in Cienfuegos, Cuba, and the associated radiation hazards(2014) Cartas-Aguila, H.A. (Héctor A.); Acosta-Milián, R. (R.); Bernal-Castillo, J.L. (José L.); Guillén-Arruebarrena, A. (Aniel); Morera-Gómez, Y. (Yasser); Alonso-Hernández, C. M. (Carlos Manuel)The radioactivity of NORM was measured in ashes collected from a fuel-oil power plant in Cienfuegos, Cuba, using an HPGe gamma-ray spectrometer. The (226)Ra, (210)Pb, (40)K, (232)Th and (238)U activity concentrations reached 240, 77, 59, 70 and 15 Bq kg(-1), respectively. The potential radiological hazard of these residuals was assessed. The radium equivalent activities of the samples varied from 54 to 345 Bq kg(-1). The gamma index was calculated to be lower than that of the reference values, and the gamma absorbed dose rate was higher than the average reported for the earth's crust; however, the assessed annual effective dose was slightly lower than the annual effective dose limit for public, i.e. 1 mSv. Therefore, these bottom ashes were not dramatically enriched with radionuclides and may be used as an additive for building materials without restrictions from a radiological protection point of view.