Soil radionuclide concentrations and radiological assessment in and around a refining and petrochemical company in Warri, Niger Delta, Nigeria

Abstract

Radioactivity measurements have been carried out using gamma-ray spectroscopy to determine the radionuclide concentrations in soil samples in the premises of the Warri Refining and Petrochemical Company located in the Niger Delta region of Nigeria and also in communities around it. The radionuclide contents of the crude oil and petroleum additives were also similarly determined. Results indicate that on the premises used by the company, the ranges of activity concentrations of (40)K, (226)Ra and (228)Th in the soil samples were 261.3-932.3 Bq kg(-1),<4.2-23.0 Bq kg(-1) and<5.1-10.2 Bq kg(-1), respectively. For the 13 villages studied, activity concentrations ranged from <17.2-766.3 Bq kg(-1),<4.2-104.7 Bq kg(-1) and<5.1-13.7 Bq kg(-1), respectively, for (40)K, (226)Ra and (228)Th. The lowest radionuclide concentrations were found in the crude oil relative to the petroleum additives. The highest outdoor effective dose rate obtained in the study was 47.5 microSv y(-1) for the villages and 35.2 microSv y(-1) within the company premises. These values are less than the world average outdoor value of 70 microSv y(-1) given by UNSCEAR. Overall, it can be concluded that the long duration of refining activities does not seem to have affected radionuclide concentrations in the environment. Measurements also showed that the observed radiation dose rates did not vary significantly from the previously determined Warri City outdoor gamma radiation dose rates, for which the probability of occurrence of any health effects of radiation was judged low. The measurements, therefore, are interpreted to represent baseline radiometric data for future reference and research in the area.

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“…The detection limit (DL), which is required to estimate the minimum detection level for appropriate determination of radionuclides in each sample were obtained using the expression[1415] (Kitto et al ., 2006, Jibiri and Emelue, 2008):…”

Natural Radioactivity Assessment and the Associated Radiological Hazards for Beach Sand, Baltim Area, Egypt.

“…The activity concentration of 226 Ra, 232 Th and 40 K radionuclides in the samples was measured using HPGe system and calculated using the following equation (Jibiri, N.N. and Emelue, H.U.,2008) [6];…”

Evaluation of the Natural Radioactivity Levels and Radiological Assessment of Nuts Commonly Consumed in Ile-Ife, South West, Nigeria

“…The annual effective dose due to the natural radionuclides in the nut samples was estimated using the dose conversion coefficient that convert the absorbed dose rate in air to the effective dose (0.7 Sv/Gy) and the outdoor occupancy of 0.2 (average of 4.8 hr spent in the site every day for a year) as proposed by UNSCEAR, 2000 [4]. The AEDR was calculated using the formula given by Jibiri and Emelue, 2008 [8].…”