Plant test systems are a sensitive way to detect the genetic effects of various contaminants in environmental compartments: water, soil and sediments. Biotesting of the genotoxicity of soil samples with various activity concentrations of naturally occurring (Ra-226, Th-232, K-40) and artificial (Cs-137) radionuclides in soil, from the territory of the Aragats Massif (Armenia) was carried out with the application of the Tradescantia micronucleus (Trad-M & Scy;N) and stamen hair mutation (Trad-SHM) bioassays of Tradescantia (clone 02) model test-object in the soil - plant system. Undisturbed soil sampling was performed in the southern slopes of the Aragats Massif, from different altitudes (from 1000 to 3200 m above sea level). The soils of the Aragats Massif exhibited a background level of naturally occurring materials (NORM) activity. The highest variability was indicated for K-40. The activity concentration of Cs-137 in soils exhibited a naturally increased as the altitude increased. Tradescantia (clone 02) was grown on the undisturbed soils in the greenhouse. To determine the level of genotoxicity of the studied soil samples, the Tradescantia-based Trad-MCN and Trad-SHM tests were applied. The activity concentrations of NORM and artificial Cs-137 in soil and phytomass were determined using an HPGe detector-based gamma spectrometer (Canberra). Tradescantia (clone 02) accumulated mainly K-40, accumulation of Ra-226 observed in one soil sample. In the areas with elevated activity of NORM, levels of genotoxicity were significantly higher compared to the control soil sample with the low rate of spontaneous mutation frequency. The positive correlation between genetic damages of Tradescantia (MCN and SSH) and contents of K-40 and Ra-226 in soils was revealed. The obtained results indicated the possibility of using Trad-MCN and Trad-SHM tests of Tradescantia (clone 02) for biotesting of background radioactivity in natural areas.

The impact of daily cattle migration from homesteads to higher altitude pastures creates severe erosion in the montane grasslands of the predominantly subsistence agricultural rural communities of KwaZulu-Natal, Drakensberg, South Africa. This study quantifies the impact of a degraded cattle path at up, mid and downslope positions on SOC and N distribution in the soil profile and within the soil aggregates. An attempt to evaluate sites of erosion and deposition using excess lead-210 (210Pbex) to support our findings was conducted. On average, the degraded cattle path reduced SOC and N in the bulk soil (by 3-4 times, respectively) and was associated with 53% reduction in aggregate stability and a 14% increase in soil bulk density over the non-degraded reference site. These results reflect the loss of vegetation cover (correlated positively to SOC and N (r approximate to 0.94)), which were triggered by cattle grazing and trampling leading to top-soil loss. Cattle hoofs damage the grass and breakdown soil aggregates, exposing the fertile topsoil particles to detachment and consequential transportation via rill and sheet erosion. This is supported by the loss of 210Pbex in the topsoil of the degraded slope positions relative to the reference site. Consistent down core mixing of 210Pbex activity in degraded slope sites supports evidence of cattle mediated soil mixing. Our findings highlight the accelerated land degradation that results from uncontrolled grazing and movement of cattle on sloping lands in the Okhombe Valley. Developing an integrated management strategy co-led by local communities to develop proactive participatory sustainable land use practices is critical for long-term landscape maintenance and recovery in the region.

The activity concentration of radionuclides in soil and crop samples obtained from Irele local government area in Ondo State, Southwestern Nigeria, was evaluated using a 760 mm x 760 mm NaI(Tl) gamma-ray detector system of model 8075, and resolution of 8 % at 0.662 MeV line of Cs-137. In addition, the radionuclide transfer from soil to crops was determined as a result. In soil samples, the mean activity concentrations of Ra-226, Th-232, and K-40 were (21.81 +/- 3.32, 12.10 +/- 4.13, 381.02 +/- 11.87 Bqkg(-1)); (31.26 +/- 3.98, 15.20 +/- 3.82, 357.46 +/- 14.62 Bqkg(-1)); (29.81 +/- 2.43, 18.86 +/- 2.34, 504.25 +/- 20.42 Bqkg(-1)) and (27.44 +/- 3.07, 21.54 +/- 3.61, 449.48 +/- 16.14 Bqkg(-1)) corresponding to plantain, maize, yam and cassava, respectively. The mean activity concentration of Ra-226, Th-232, and K-40 for plantain, maize, yam and cassava samples are (13.27 +/- 4.58, 6.48 +/- 3.94, 265.81 +/- 13.19 Bqkg(-1)); (27.03 +/- 3.70, 10.72 +/- 3.07, 345.70 +/- 14.63 Bqkg(-1)); (24.03 +/- 4.65, 13.79 +/- 4.25, 523.53 +/- 16.43 Bqkg(-1)) and (21.47 +/- 3.57, 14.44 +/- 2.20, 432.99 +/- 18.56 Bqkg(-1)), respectively. The mean transfer factor values of 226Ra, 232Th and 40K are (0.611, 0.536, 0.700); (0.867, 0.708, 0.967); (0.807, 0.736, 1.040) and (0.785, 0.668, 0.974) for soil-to-plantain, soil-to-maize, soil-to-yam, and soil-to-cassava, respectively. The results revealed that the transfer factor of the crop samples is in the following order: yam>cassava>maize>plantain. The activity concentrations of Ra-226, Th-232, and K-40 in the soil and crop samples and corresponding soil-to-crop transfer values did not cause radiation damage to human health as reported levels were below recommended limits. The results of this study may serve as the basis and future criteria for the radionuclide concentrations in soil and their migration factors for the various crops in the study area

Naturally occurring radioactive materials (NORMs: 232Th, 226Ra, 40K) can reach our respiratory system by breathing of road dust which can cause severe health risks. Targeting the pioneering consideration of health risks from the NORMs in road dust, this work reveals the radioactivity abundances of NORMs in road dust from a megacity (Dhaka) of a developing country (Bangladesh). Bulk chemical compositions of U, Th, and K obtained from neutron activation analysis were converted to the equivalent radioactivities. Radioactivity concentrations of 226Ra, 232Th, and 40K in road dust ranged from 60-106, 110-159, and 488-709 Bq kg-1 with an average of 84.4 +/- 13.1, 126 +/- 11, and 549 +/- 48 Bq kg-1, respectively. Estimated 226Ra, 232Th, and 40K radioactivities were, respectively, 1.7-3.0-, 3.7-5.3-, and 1.2-1.8-folds greater than the affiliated world average values. Mechanistic pathway of NORMs' enrichment and fractionation relative to the major origin (pedosphere) were evaluated concerning the water logging, relative solubility-controlled leaching and translocation, climatic conditions, and aerodynamic fractionations (dry and wet atmospheric depositions). Computation of customary radiological risk indices invokes health risks. Noticing the ingress of NOMR-holding dust into the human respiratory system along with the associated ionizing radiations, the computed radiological indices represent only the least probable health hazards. Nevertheless, in real situations, alpha-particles from the radioactive decay products of 232Th and 238U can create acute radiation damages of respiratory system. Policymakers should emphasize on limiting the dust particle evolution, and public awareness is required to alleviate the health risks.

Layers of permafrost developed during the 1950s and 1960s incorporated tritium from the atmosphere that originated from global nuclear weapons testing. In regions underlain by substantial permafrost, this tritium has been effectively trapped in ice since it was deposited and subject to radioactive decay alone, which has substantially lengthened its environmental half-life compared to areas with little or no permafrost where the weapons-test era precipitation has been subject to both decay and hydrodynamic dispersion. The Arctic is warming three times faster than other parts of the world, with northern regions incurring some of the most pronounced effects of climate change, resulting in permafrost degradation. A series of 23 waterbodies across the Canadian sub-Arctic spanning the continuous, discontinuous and isolated patches permafrost zones in northern Manitoba, Northwest Territories and Labrador were sampled. Surface water and groundwater seepage samples were collected from each lake and analyzed for tritium, stable isotopes (delta O-18 and delta H-2) and general water chemistry characteristics. Measured tritium was significantly higher in surface waters (SW) and groundwater seepage (GW) in water bodies located in the sporadic discontinuous (64 +/- 15 T U. in SW and 52 +/- 9 T U. in GW) and extensive discontinuous (53 +/- 7 T U. in SW and 61 +/- 7 T U. in GW) permafrost regions of the Northwest Territories than in regions underlain by continuous permafrost in northern Manitoba (< 12 T U. in both SW and GW) or those within isolated patches of permafrost in Labrador (16 +/- 2 T U. in SW and 21 +/- 4 T U. in GW). The greatest tritium enrichment (up to 128 T U.) was observed in lakes near Jean Marie River in the Mackenzie River valley, a region known to be experiencing extensive permafrost degradation. These results demonstrate significant permafrost degradation in the central Mackenzie River basin and show that tritium is becoming increasingly mobile in the sub-Arctic environment-at concentrations higher than expected-as a result of a warming climate. A better understanding of the cycling of tritium in the environment will improve our understanding of Arctic radioecology under changing environmental conditions.

Soils in ice-free areas of Elephant Island (South Shetland Islands) have been forming since the last deglaciation following the glacial retreat that started in the area probably later than 9.7-5.5 ka. In paraglacial landscapes, landforms and processes in transition from glacial to nonglacial conditions are experiencing rapid environmental adjustments under conditions of climate change. Soils are highly sensitive and can be good descriptors of these transitional changes. A soil sampling campaign was undertaken for characterizing soils developed on moraines and marine platforms, underlain by metamorphic rocks and with distinctive periglacial features. Eight soil profiles were sampled to investigate the processes involved in their development and the relations with main landforms and processes of ice retreat. The stony Cryosols with mosses and lichens coverage are developed in permafrost environment with an active layer depth of 15-150 cm. Soil organic C content (0.16-1.6%) and large variations of P, K and N contents are related to ornithogenic activity. Soils on moraines and platforms show differences that reflect the more recent exposure of moraines that preserve most the characteristics of the parent material. More vegetated soils on platforms show Cs-137 and Pb-210(ex) activities (11 and 25 Bq kg(-1), respectively) at the topsoil whereas absence of Cs-137 and depleted levels of Pb-210(ex) occurred in more recently exposed and less developed soils on moraines. Fallout radionuclides are good tracers for identifying characteristics of soil development and providing information on environmental changes of interest to understand the soil response to actual changes in unstable paraglacial environments.