Radioactive Disequilibrium and Dynamic of Natural Radionuclides in Soils in the State of Pernambuco—brazil

Abstract

Environmental radioactivity studies have been allowed establishing radiometric patterns in several area of the earth's crust. The work was conducted through radiometric analyses of regions with high levels of radionuclides and others with no history of anomalies. The research allowed establishing the radiometric profile of soils in the state of Pernambuco, Brazil, using a gamma spectrometry system. The specific activities ranged from 16.5 to 287.5 Bq kg-1 for 238U, 2.0 to 191.7 Bq kg-1 for 226Ra, 1.3 to 281.4 Bq kg-1 for 232Th and from 5.0 to 2600.9 Bq kg-1 for 40K. The results showed areas with low levels of ionizing radiation. However, for 40K some points presented high values, although non-representative of the number of samples investigated. The 226Ra/238U and 232Th/238U ratios allowed to determine the radioactive imbalance condition and to obtain information about aspects of soil availability providing an assessment of the dynamics of these radionuclides.

Measurement of radioactivity in soils of Karamjal and Harbaria mangrove forest of Sundarbans for establishment of radiological database

“…Additionally, the lithosphere naturally contains three times as much thorium as uranium or radium [40]. Each location in the world has different geological and topographical conditions, which affect radioactivity in soils [41][42][43]. Variations in soil activity levels can be attributed to factors such as the soil-to-water ratio, the rate and amount of rainfall, soil drainage, site characteristics, and other environmental variables like meteorological conditions, soil use patterns, fertilizer use, evaporation, etc.…”

Radiological and health hazards resulting from radioactivity and elemental composition of some soil samples

“…The values of the gamma index were ranged from 0.2139 to 0.3629. It's observed that each one sample has gamma index Iγ<1 which suggests gamma dose rate emission from these samples was not exceeding 0.3 mSv/y [25]. The calculated values of H ex were found to vary from 0.0794 to 0.1368, with a mean value of 0.1094.…”

Evaluation of 210Pb levels in the estuarine region of an industrial complex

“…The specific activities of 226 Ra radionuclides were calculated by applying Equation 3 (Santos Júnior et al, 2018):…”

“…The 212 Pb (half-lives (t1 / 2) short 10.64 hours), 211 Pb (half-lives (t1 / 2) short 36.1 minutes), and 214 Pb (half-lives (t1 / 2) short 26, 8 minutes) and therefore they do not migrate to great distances in the environment. On the other hand, 210 Pb with a half-life of 22.26 years was found in many environmental samples (Santos Júnior et al, 2018). 210 Pb can be found adsorbed to atmospheric particles and can return to the soil by the action of rain, in which they can form compounds and rapidly distributed in the environment (Silva et al, 2018).…”