Environmental radioactivity assessment of the Brunei Darussalam coastline of the South China Sea

Investigating radiation profiles and conducting risk assessment for ecological and environmental components on Vaan and Koswari islands in the Tuticorin group of islands, India

Natural radioactive concentration assessment was conducted on sediment, water, and biota obtained on Vaan and Koswari islands in the Tuticorin group of islands, Tamil Nadu, India. For biotic and abiotic components, radiation profiles such as gross alpha, beta, primordial radionuclide, polonium, and lead analyses were performed. The gross α and β range from BDL to 15.18 ± 1.7 Bq/kg and 40.43 ± 4.9 Bq/kg to 105.12 ± 11.7 Bq/kg, respectively. Primordial radionuclides were analyzed using Nal(TI)-based scintillator with PC-MCA, and the concentrations ranged from 13.43 ± 3.3 Bq/kg to 30.97 ± 9.6 Bq/kg with a mean of 21.31 ± 2.7 Bq/kg for 238U; for 232Th, the values ranged from 11.09 ± 2.6 Bq/kg to 33.55 ± 9.5 Bq/kg with an average value of 23.89 ± 3.7 Bq/kg; and for 40 K, the values are 93.33 ± 27.3 Bq/kg to 219.91 ± 39.6 Bq/kg with an average value of 148.27 ± 21.7 Bq/kg. The present study values are lesser than the world average values. 210Po and 210Pb concentrations with an average value were determined to be 33.13 Bq/L and 16.56 Bq/L, 47.55 Bq/L and 22.37 Bq/L in the water sample, and 50.437 Bq kg1 and 62.012 Bq kg1, 46.99 Bq/kg and 58.625 Bq/kg in sediments of Vaan island and Koswari island. The concentrations of 210Po and 210Pb of Pogonias cromis were 19.27 ± 1.5 Bq/kg and 8.27 ± 1.01 Bq/kg, Belonidae 28.54 ± 2.4 Bq/kg and 18.32 ± 2.3 Bq/kg, Lepisosteidae 18.68 ± 1.4 Bq/kg and 11.17 ± 1.8 Bq/kg. The committed effective dosage was determined to be 35.74-54.61 µSv/y for 210Po and 25.39-56.25 µSv/y for 210Pb, in which the 210Pb value is lower; however, the 210Po value is higher than the global average value. The annual committed effective dosage as well as the radiological hazard indices were assessed and found to be much below the global average and the recommended limit, respectively. This research provides an extensive analysis of natural background radiation and establishes a baseline report on the radiological profile of biotic and abiotic factors in the Tuticorin group of islands, namely Vaan and Koswari, in Tamil Nadu, India.

Radiological risk assessment of beaches from volcanic oceanic islands: A case study of the Eastern Canary Islands (Spain)

This work constitutes the first survey that allows the establishment of baseline levels of environmental radioactivity in beach sands from the volcanic oceanic islands of La Graciosa, Lanzarote, Fuerteventura and Gran Canaria. Activity concentration values of 226Ra, 232Th and 40K were measured by gamma spectroscopy in 108 samples, collected from 39 beaches across the whole study region. The radiological hazard risks associated with these sands were studied. The mean absorbed dose rate in the study region was 20 nGy h-1, which is below the world average value. The mean outdoor annual effective dose for the beaches studied was 0.025 mSv y-1, which is within the internationally accepted safe limit. Additionally, the assessment of the radium equivalent showed that all samples from the Eastern Canary Islands are below the safe limit of 370 Bq kg-1. Despite not posing any radiological risk to the human population, the radiological hazard indices obtained in Gran Canaria were significantly higher than those of other islands. These significant differences seem to be related to the presence of sediments in the beaches of Gran Canaria that have their origin in lithologies with higher activity concentration values of 226Ra, 232Th and 40K that are not present in the rest of the islands.