Heavy Metal Assessments of Soil Samples from a High Natural Background Radiation Area, Indonesia

Mamuju, Indonesia, is an area with high natural background radiation. This study assesses heavy metal content in soil samples from this area to determine the level of public and environmental hazard it presents. This study analyzes natural radionuclide elements using high purity germanium (HPGe) gamma spectrometry and performs heavy metals analysis using a flame atomic absorption spectrometry (FAAS). Moreover, pollution indices and descriptive analyses were used to assess heavy metal contamination in the environment and the correlation between heavy metals and radionuclides. The results demonstrate that soil samples in several areas of Mamuju contain a high concentration of the natural radionuclides 226Ra and 232Th, and that heavy metal concentrations in the soil decrease in the sequence Zn > Pb > Cr > Cu > Ni > Cd. This study revealed that soil samples from Mamuju are moderately contaminated. There was a strong positive relationship between 226Ra, 232Th, ambient dose equivalent rate, and Pb. Ecological risk index (RI) and cumulative pollution index (IPI) values in Mamuju are 2.05 and 125, respectively, which are possible hazards to human health as a result. Pb concentration in the Mamuju soil samples ranged from 109 to 744 mg kg−1, exceeding the worldwide average of 27 mg kg−1.

An Innovative Framework on Spatial Boundary Optimization of Multiple International Designated Land Use

The continuous improvement of international protection awareness has dramatically increased the number of protection organizations and promoted various reserve-naming methods. However, the existing global natural reserves have either fully or partially overlapped, thereby allowing the same region to hold various international titles, resulting in serious issues, which are especially manifested in the boundary delimitation process of natural reserves. Therefore, delimiting the titles of reserve borders will become an enormous challenge in protected-area governance worldwide. This study conducted an in-depth investigation of the technical methods for delineating the spatial boundaries of natural reserves. Taking Jiangshan Nature Reserve in China as the case object, the Candidate Area–Natural background–Heritage Resource–Construction (C-NHC) framework was constructed, and the boundaries of the new reserves were delineated. This study has changed the status quo of the spatial overlap of the reserve through the quantitative evaluation of the conflict patches and the triple optimization of the boundary of the reserve. The area of the new reserve is 150.524 km2, which is 6.682 km2 larger than the original one. The original reserves are all included within the scope of the new one. This study provides guidance and new insights into the boundary delineation of integrated nature reserves worldwide.

Outdoor and indoor natural background gamma radiation across Kerala, India

The average annual outdoor background radiation dosage across the study area was ∼two times greater than the world average. Higher radiation dosage was observed in indoor environments than outdoors in the majority of the sampling locations.

Consideration of the contribution of the natural background component during individual control of radiation doses to personnel

When ensuring radiation safety in the Russian Federation, there is a principle of separate independent assessment of doses from natural, medical, emergency and technogenic exposure. In practice, it is not always possible to comply with this principled approach. The established dose limits are related only to man-made radiation during normal operation of sources of ionizing radiation. However, during the formation of regional and federal databases on individual doses of personnel exposure, information is entered not on technogenic exposure, but on industrial exposure, that is, without subtracting the natural radiation background. The natural component of the individual dose at low radiation doses is quite significant. Failure to its subtraction leads to an overestimation of the individual dose of external exposure of personnel. Difficulties arise in the implementation of the subtraction of the natural radiation background: 1) in what cases it is necessary to subtract the background, 2) what value to choose for the subtracted background, 3) what method to measure the background, 4) at what stage of processing the measurement information to subtract the background. This article proposes a method for solving the problem of subtracting the natural background radiation from the values of individual doses of external exposure to personnel based on results of individual dosimetric control. Using the example of the city of St. Petersburg, the natural background radiation was measured by the thermoluminescent method of individual dosimetry at 50 control points for three consecutive years (2018-2020). To measure the natural background, we used individual thermoluminescent dosimeters of the same type as those used to measure individual equivalents of external radiation doses to personnel. The choice of using the thermoluminescent method as a predominant one for adjusting the average doses of external radiation from technogenic sources of ionizing radiation when subtracting the natural component of the dose has been substantiated. Comparison of official data on personnel exposure doses with the data obtained as a result of our own measurements is made. Recommendations are given on the use of the obtained values of the average natural radiation background in the formation of regional and federal databases on individual doses of personnel exposure.

Forecasting the radiation background in the territories of Kazakhstan located near the uranium mining industries

A significant part of the territory of Kazakhstan is characterized by a high natural background radiation of soils and rocks, the spread of natural ground and underground waters with high concentrations of radionuclides in the regions of uranium, thorium and rare metal ore provinces and regions. Therefore, conducting high-quality radio monitoring of the state of the environment using modern information systems will make it possible to predict the background radiation in a timely manner and outline measures to reduce environmental risks to the health of the nation as a whole. Key words: radioecology, monitoring, life safety, radionuclides, national health.

The need to review low-dose decision-making in radiation protection

The current approach in the system of protection, and the way in which it is implemented in regulation and practical application, has resulted in the allocation of significant and disproportionate societal resources to reduce relatively low-level exposures to even lower levels. The resulting exposure levels are often a fraction of the basic natural background level, and in particular are comparable to, or often significantly less than, the variability of natural background exposures due to individual decision-making, which the system of protection deems acceptable. There are arguments for a wider approach to decision-making at such low doses, recognising the uncertainties in radiation risk estimation and acknowledging the context that all human life takes place in a variable natural background radiation which generally dominates these lower dose exposures. Recommendations are presented for improvements in how decisions are made in controlling low doses.

Wildfire activity enhanced during phases of maximum orbital eccentricity and precessional forcing in the Early Jurassic

Fire regimes are changing due to both anthropogenic climatic drivers and vegetation management challenges, making it difficult to determine how climate alone might influence wildfire activity. Earth has been subject to natural-background climate variability throughout its past due to variations in Earth’s orbital parameters (Milkankovitch cycles), which provides an opportunity to assess climate-only driven variations in wildfire. Here we present a 350,000 yr long record of fossil charcoal from mid-latitude (~35°N) Jurassic sedimentary rocks. These results are coupled to estimates of variations in the hydrological cycle using clay mineral, palynofacies and elemental analyses, and lithological and biogeochemical signatures. We show that fire activity strongly increased during extreme seasonal contrast (monsoonal climate), which has been linked to maximal precessional forcing (boreal summer in perihelion) (21,000 yr cycles), and we hypothesize that long eccentricity modulation further enhances precession-forced fire activity.