Radiological and pollution risk assessments of terrestrial radionuclides and heavy metals in a mineralized zone of the siwalik region (India)

Integrated pollution analysis, pollution area identification and source apportionment of heavy metal contamination in agricultural soil

Given the global prevalence of soil heavy metal contamination, knowledge concerning of soil environmental quality assessment, pollution area identification and source apportionment is critical for implementation of soil pollution prevention and safe utilization strategies. In this study, soil static environmental capacity (QI) for heavy metals was selected to evaluate pollution risks in agricultural soils of Wenzhou, southeast China. Combined with geostatistical methods, the pollution area was identified along with uncertainty analysis. Potential sources were quantitatively apportioned using a positive matrix factorization model (PMF). Results showed that agricultural soils in this study were mainly contaminated by Cd and Pb based on both Nemerow and QI indices. The environmental capacity assessment found more than 90% areas were identified as polluted soils for Qi-Zn, Qi-Cd and Qi-Pb, with minor uncertain areas. Cu was identified as having a high proportion of uncertain pollution area status, which was similar to the results of the integrated environmental capacity for all metals. PMF results indicated that industrial discharge, agrochemicals and parent material accounted for 32.1%, 32.2% and 35.7% of heavy metal accumulation in soils, respectively. Implementation of strict policies to reduce anthropogenic source emissions and remediate soil pollution are crucial to minimize metal pollution inputs, improve agricultural soil quality and enhance food safety.

Satellite or ground-based measurements for air pollutants (PM2.5, PM10, SO2, NO2, O3) data and their health hazards: which is most accurate and why?

Air pollution is growing at alarming rates on regional and global levels, with significant consequences for human health, ecosystems, and change in climatic conditions. The present 12 weeks (4 October 2021, to 26 December 2021) study revealed the different ambient air quality parameters, i.e., PM2.5, PM10, SO2, NO2, and O3 over four different sampling stations of Delhi-NCR region (Dwarka, Knowledge park III, Sector 125, and Vivek Vihar), India, by using satellite remote sensing data (MERRA-2, OMI, and Aura Satellite) and different ground-based instruments. The ground-based observation revealed the mean concentration of PM2.5 in Dwarka, Knowledge park III, Sector 125, and Vivek Vihar as 279 µg m-3, 274 µg m-3, 294 µg m-3, and 365 µg m-3, respectively. The ground-based instrumental concentration of PM2.5 was greater than that of satellite observations, while as for SO2 and NO2, the mean concentration of satellite-based monitoring was higher as compared to other contaminants. Negative and positive correlations were observed among particulate matter, trace gases, and various meteorological parameters. The wind direction proved to be one of the prominent parameter to alter the variation of these pollutants. The current study provides a perception into an observable behavior of particulate matter, trace gases, their variation with meteorological parameters, their health hazards, and the gap between the measurements of satellite remote sensing and ground-based measurements.

Geochemical Distribution and Environmental Risks of Radionuclides in Soils and Sediments Runoff of a Uranium Mining Area in South China

Uranium mining activities have contributed to the distribution and uptake of radionuclides, which have increased the active concentrations of natural radionuclides in environmental media, causing elevated human health risks. The present study aims to assess the spatial distribution characteristics of natural radionuclides in the surface soils and river sediments of the typical granite uranium mining area in South China, as well as investigate the geochemical features of natural radionuclides in the soil and sediments to understand their migration processes. The activity concentrations for 238U, 226Ra, 232Th, and 40K ranged from 17-3925 Bq/kg, 50-1180 Bq/kg, 29-459 Bq/kg, and 240-1890 Bq/kg, respectively. The open-pit mining areas and tailings pond locations exhibited the highest concentrations of activity for all these radionuclides. This distribution points to an elevated potential health risk due to radiological exposure in these specific areas. Additionally, the values of radium equivalent activity (Raeq) and annual gonadal dose equivalent (AGDE) in those areas were higher than the limits recommended by ICRP (2021). 238U and 226Ra have a significant correlation (0.724), and the cluster analysis was showing a statistically meaningful cluster below 5 indicated that they have similar behavior during parent rock weathering and watershed erosion, and the distribution of 232Th and 40K were influenced by the addition of rock types. The activity ratios of 226Ra/238U, 226Ra/232Th, 238U/40K, and 226Ra/40K variation indicated that 40K more mobile than 226Ra and 238U, U(VI) was reduced to U(IV) by organic matter in the downstream area and re-entered into the sediment during the sediment surface runoff in the small watershed of the uranium ore open-pit mining area. Therefore, it is necessary to further seal up and repair the tailings landfill area.

A review on radionuclide pollution in global soils with environmental and health hazards evaluation

Human populations are being exposed to a wide spectrum of radiation from soils as a result of the availability of radiation sources. Assessing the ecological and health effects of radionuclides in soils is crucial to support the optimal soil management practices but large-scale studies are limited. This study compiled data on radionuclides (226Ra, 232Th, 40K, 238U, and 137Cs) in soils located across the world (44 countries and 159 places) between 2008 and 2022 and applied radiological hazards indices and several multivariate statistical approaches. The average activity concentration (Bq/kg) of 226Ra, 232Th, 40K, 238U, and 137Cs were 408.56, 144.80, 508.78, 532.78, and 83.12, respectively, whereas 226Ra, 232Th, 40K, and 238U exceeded the standard limits. The principal component analysis explained more than 91% of variation in soils. Based on the geoaccumulation index, 40K posed moderately to heavy contamination whereas 238U and 226Ra posed moderate contamination in soils. Moreover, the mean values of radiological hazards evaluation such as radium equivalent activity (487.17 Bq/kg), external radiation hazard indices (1.32), internal hazard indices (2.15), absorbed dose rate (247.86 nGyh-1), annual effective dose rate (1.82 mSvy-1), activity utilization index (4.54) and excess lifetime cancer risk (63.84 × 10-4) were higher than recommended limit suggesting significant radiological risks in study region soils. The findings indicated that the study area soils were contaminated by radionuclides and unsafe for hazards in terms of the health risks linked with studied radioactive contents. The study is valuable for mapping radioactivity across the globe to determine the level of radioactivity hazards.

Geochemical distributions of natural radionuclides in surface soils and sediments impacted by lead-zinc mining activity

This study investigated the distribution features of uranium-238 (238U), radium-226 (226Ra), thorium-232 (232Th), and potassium-40 (40K) and evaluated the associated environmental radiological hazards of the topsoil and river sediments in the Jinding lead-zinc (Pb-Zn) mine catchment from Southwest China. The activity concentrations of 238U, 226Ra, 232Th, and 40K ranged from 24.0 ± 2.29-60.3 ± 5.26 Bq.kg-1, from 32.5 ± 3.95-69.8 ± 3.39 Bq.kg-1, from 15.3 ± 2.24-58.3 ± 4.92 Bq.kg-1, and from 203 ± 10.2-1140 ± 27.4 Bq.kg-1, respectively. The highest activity concentrations for all these radionuclides were primarily found in the mining areas and decreased with increasing distance from the mining sites. The radiological hazard indices, including radium equivalent activity, absorbed gamma dose rate in the air, outdoor annual effective dose equivalent, annual gonadal dose equivalent, and excess lifetime cancer, revealed that the highest values were observed in the mining area and downstream, specifically in the vicinity of the ore body. These elevated values exceeded the global mean value but remained below the threshold value, suggesting that routine protection measures for Pb-Zn miners during production activities are sufficient. The correlation analysis and cluster analysis revealed strong associations between radionuclides such as 238U, 226Ra, and 232Th, indicating a common source of these radionuclides. The activity ratios of 226Ra/238U, 226Ra/232Th, and 238U/40K varied with distance, suggesting the influence of geological processes and lithological composition on their transport and accumulation. In the mining catchment areas, the variations in these activity ratios increased indicated the impact of limestone material dilution on the levels of 232Th, 40K, and 238U in the upstream region. Moreover, the presence of sulfide minerals in the mining soils contributed to the enrichment of 226Ra and the removal of 238U caused those activity ratios decreased in the mining areas. Therefore, in the Jinding PbZn deposit, the patterns of mining activities and surface runoff processes in the catchment area favored the accumulation of 232Th and 226Ra over 40K and 238U. This study provides the first case study on the geochemical distributions of natural radionuclides in a typical Mississippi Valley-type PbZn mining area and offers fundamental information on radionuclide migration and baseline radiometric data for PbZn deposits worldwide.

Natural and anthropogenic radionuclides concentration with heavy metals analysis of the sediments collected around Novaya Zemlya

The Dispersal profile of the radioisotopes (226Ra, 232Th, 235U, 40K, 137Cs) along with potentially toxic elements (Cd, Co, Cr, Cu, Ni, Pb, V, Zn, and Hg) in the sediments around the Novaya Zemlya was determined. The task was fulfilled with the aid of HPGe gamma spectrometry, inductively coupled plasma optical emission spectroscopy, DMA-80 Direct Mercury Analysis System, X-ray diffraction and statistical tools. At most of the locations, the radionuclides activity was higher than the world average activity concentration for the respective nuclei, 40K being the most abundant. From all the potentially toxic elements detected, Cr and Ni were usually observed on higher levels compared to their background values, indicating the probability of the detrimental biological effects. Thus, the present situation at the studied area might be a threat to the neighboring marine life.

Spatio-temporal variation and hazard assessment of potentially toxic metal element contamination in sediments and water before and after a water-level fluctuation cycle in the Three Gorges Reservoir, Wanzhou, China

Previous investigations on heavy metals in the water-sediment compartment focused on their spatial distribution, and the influence of sediment pH and organic matter (OM) on metal environmental occurrences. However, there are limited studies on the effects of physicochemical properties on the migration and transformation of heavy metals in the water-sediment compartments. This study investigated the relationship between the physicochemical properties of sediments and the distribution and chemical speciation of heavy metals, and the potential environmental risk of heavy metals in water and sediment using Risk Assessment Code (RAC) values and the Tessier five-step extraction method. Adsorption and desorption experiments showed that the sediment had weak adsorption and the strongest desorption capacity for Cd. Results of the pH, OM, surface element content, and X-ray diffraction (XRD) patterns suggested that cadmium (Cd) was more likely to partition into the water phase from the sediment during the flooding and water storage periods. When pH was 7-8 and OM content was 3.6-5.9%, the sediment-water distribution coefficient of Cd was low due to its large ionic radius, and the surface adsorption sites were saturated by other elements. These studies can provide a theoretical basis for the management and pollution control of the Three Gorges Reservoir.

Sorption behavior studies of Cs and its migration in soil samples around Visakhapatnam, India

Meeting the requirement of high specific activity of radioisotopes and carrying out comprehensive research and development activities in the nuclear field, different nuclear facilities, including their waste disposal facilities, are going to be operational at Visakhapatnam, India. Due to environmental processes, the engineered disposal modules may lose their structural integrity and may release some radioactivity to the geo-environment. The subsequent migration of radionuclides reaching the geological environment will be governed by the distribution coefficient (K_d). Cs was chosen for the sorption study in two soil samples (soil-29 and 31) and to estimate the K_d in all the 40 soil samples through the laboratory batch method at the new campus of DAE, Visakhapatnam, India. Different soil chemical parameters like pH, organic matter, CaCO₃, and cation exchange capacity were determined in 40 soil samples and their effect on Cs sorption was investigated. The effect of solution pH and initial concentration of Cs on sorption was also studied. The results show that the sorption of Cs increases with increasing pH. The Cs sorption was well explained by Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Site-specific distribution coefficients (K_d) were also estimated and the values were found to vary from 75 ± 1 to 540 ± 12 L kg^-1. The observed wide variation in K_d could be due to large variations in the physico-chemical properties of collected soil. The competitive ions effect study suggests that K⁺ has higher interference for Cs⁺ sorption as compared to Na⁺. The present study results will help assess the environmental impact due to Cs release in any unforeseen scenario and in planning effective remediation strategies.

Sorption and transport characteristics of europium on sandy soils

Radioactive europium can be released as a fission product during nuclear incidents and pose a threat to the human and surrounding environment because of its biological activity and long decay half-lives. For safe design issues and human health protection demands in construction of the planned nuclear power plants (NPPs) at Al-Dabaa site, it is necessary to study the sorption and transport of different radionuclides as europium within the selected area for predicting their fate at any crisis. Many soil samples were collected from different locations at the area selected along the northwestern coast of Egypt. The samples were transported to the laboratory, preserved, and characterized using X-Ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR), and X-Ray diffraction (XRD). Experiments were performed to study the sorption and transport kinetics of Eu(III) ions on two sandy soil samples from the collected ones. The effect of different parameters (e.g. contact time, pH, initial europium concentration, and temperature) on the sorption behavior europium was explored in a static condition. The maximum sorption capacity was determined and found to be 3.4 and 7.0 mg g^-1 for sorption of Eu(III) ions onto soil-1 and soil-2, respectively. Different models were applied to assess the sorption of europium onto the surface of the investigated soils. Data confirmed that Eu retention was attained through a chemisorption process. Further, the thermodynamic parameters were determined and their values confirmed the endothermic nature of the sorption process. The transport of europium radionuclides, with groundwater, through homogeneous porous media with uniform one-dimensional flow in the geosphere was processed and the relative migration velocity was determined in presence of both distilled and seawater media. The transport of Eu(III) radionuclides was higher in presence of seawater than that in presence of distilled water by about two order of magnitude. This obviously clarified the effect of seawater in accelerating the transport of radionuclides with groundwater in the geosphere of studied area. The role of different competing ions have various valances on the relative migration velocity was explored. Further, the time required for studied radionuclides to reach Mediterranean Sea was determined.

Investigation of heavy metal contamination and associated health risks in groundwater sources of southwestern Punjab, India

Human body exposure to various toxic and non-toxic heavy metals in groundwater is a significant health concern, especially in developing countries. The present study was planned and carried out to appraise the potential health risks of eight heavy metals (Mn, Co, Cu, As, Se, Cd, Hg, and Pb) in different water sources of the Mansa and Muktsar districts of Punjab. The measurements of heavy metals were performed using the inductively coupled plasma mass spectrometry (ICPMS) technique. The health (carcinogenic and non-carcinogenic) risks and doses (ingestion and dermal) associated with exposure to heavy metals in water were estimated from the measured concentrations using USEPA guidelines. The average concentrations of heavy metals were observed in the order of Mn (13.93) > Cu (13.12) > Se (4.14) > As (3.28) > Hg (3.27) > Pb (1.29) > Co (0.20) > Cd (0.10) μg L^-1. The results show that the Hg, Pb, As, and Se concentrations are above the guideline values of the World Health Organization (WHO) in 10.34%, 3.45%, 6.90%, and 6.90% locations, respectively. The high values of these heavy metals may be due to geogenic anthropogenic activities. The hazard quotients (non-carcinogenic risk) for ingestion and dermal exposures were observed in the range of 0.32-3.79 and 8.05 × 10^-6-1.34 × 10^-4, respectively. On the other hand, the carcinogenic health risks due to ingestion and dermal exposure were observed to be 0.02-0.38 and 6.67 × 10^-8-1.15 × 10^-6, respectively. The results of this study will be helpful to the drinking water supplying agencies, water resource development authorities, etc.

Impact of physiochemical properties, microbes and biochar on bioavailability of toxic elements in the soil: a review

The pollution of toxic elements (TEs) in the ecosystem exhibits detrimental effects on the human health. In this paper, we debated remediation approaches for TEs polluted soils via immobilization methods employing numerous amendments with reverence to type of soil and metals, and amendment, immobilization competence, fundamental processes and field applicability. We argued the influence of pH, soil organic matter, textural properties, microbes, speciation and biochar on the bioavailability of TEs. All these properties of soil, microbes and biochar are imperative for effective and safe application of these methods in remediation of TEs contamination in the ecosystem. Further, the application of physiochemical properties, microbes and biochar as amendments has significant synergistic impacts not only on absorption of elements but also on diminution of toxic elements.

Distribution, ecological risk assessment and source identification of pollutants in soils of different land-use types in degraded wetlands

BACKGROUND

Urbanization and global warming are generating ecological degradation and land pattern alteration problems in natural wetlands. These changes are greatly affecting the ecological services of wetlands. Therefore, there is an urgent need to explore the relationship between pollutants and land-use type for wetland restoration purposes. Zaozhadian Lake is a freshwater wetland in the North China Plain, which is facing degradation and land-use types changes. An experiment for analyzing soil pollutants was conducted in three land-use types of farmland, lake, and ditch in the Zaozhadian Lake. The aims of this study were to identify the distribution, pollution degree, and sources of pollutants in different land-use types, and to explore the influence of land-use type changes on contamination.

METHODS

In this study, surface sediments (0-10 cm) of three land types (farmland, lake, and ditch) in Zaozhadian Lake were collected, and heavy metals (Cu, Ni, Zn, Pb, Cd, Cr, Hg), As, total nitrogen (TN), total phosphorus (TP) and organic matter (OM) were determined. Kriging interpolation was used to visualize the pollutants distribution. The pollution degree of TN and TP was evaluated by the Nemerow pollution index. The pollution of heavy metals and As was evaluated by the geological accumulation index (I_geo ) and the potential ecological risk index (RI). Then, dual hierarchical clustering analysis and the principal component analysis were performed to further analyze the impact of land type changes on pollutants.

RESULTS

The heavy metal contents in the farmland were higher than other areas, while the TN (3.71 ± 1.03 g kg^-1) and OM (57.17 ± 15.16 g kg^-1) in lake sediments were higher than that in other regions. Farmland, lake, and ditches had low ecological risks, with RI values of 84.21, 71.34, and 50.78, respectively. The primary heavy metal pollutants are Pb, Cu, and Ni. Furthermore, Cu, As, Ni, Pb, and Zn were primarily derived from agriculture pollution, the source of Cd was the industrial pollution, and Cr mainly originated from natural sources. Nutrients primarily came from the decomposition of aquatic animals, plants, and human-related activities. When the lake area was converted into farmland, the heavy metal concentrations in the soils increased and the TN and OM decreased. Based on the results, this study put forward key strategies including the adjustment of the land-use type and restriction of the entry of pollutants into the wetland ecosystems in the Zaozhadian Lake. More attention should be paid to the impact of land-use type change on pollutants in wetlands.

Assessing heavy metal contamination in soils using improved weighted index (IWI) and their associated human health risks in urban, wetland, and agricultural soils

Contamination of nine heavy metals (HMs) Zn, Pb, Cu, Cd, As, Co, Cr, Mo, and Ni in agricultural, urban, and wetland soils from Western and Rift Valley parts of Kenya was assessed using improved weighted index (IWI) and pollution loading index (PLI). Non-carcinogenic risks posed by the HMs were assessed using hazard quotients (HQ) and hazard index (HI), while carcinogenic risks were assessed using cancer risks (CR) and total cancer risks (TCR). The average concentration of Zn, Cr, Ni, Pb, Co, Cu, As, Mo, and Cd was 94.7 mg/kg, 43.6 mg/kg, 22.3 mg/kg, 21.0 mg/kg, 19.8 mg/kg, 18.0 mg/kg, 16.3 mg/kg, 1.83 mg/kg, and 1.16 mg/kg, respectively. IWI ranged from 0.57 to 6.04 and categorized 6.82% of the study sites as not polluted, 27.3% as slightly polluted, 43.2% as moderately polluted, and 22.7% as seriously polluted. PLI ranged from 0.38 to 3.95 and classified 15.9% of the sites as not polluted, 61.4% as slightly polluted, 20.5% as moderately polluted, and only 2.3% as seriously polluted. Wetlands retained more HMs from both urban and agricultural runoff and were therefore the most polluted. The heavy metals did not pose any risks via inhalation and dermal contact, but HQingestion for As for children was >1 in 2.3% of the sites studied. CR via ingestion and TCR for As were above the allowable limits for children and adults indicating high risks of cancer. Intensive agriculture and urbanization should be closely monitored to prevent further HM pollution.

Accumulation risk and source apportionment of heavy metals in different types of farmland in a typical farming area of northern China

The types of land used for farmland can greatly influence the source and accumulation risk of heavy metals in soil. However, the apportioning quantitatively the source of soil heavy metals has been studied insufficiently, especially in terms of different types of farmland. In this study, a total of 252 soil samples were taken from dry land, paddy fields and greenhouse fields in the Jinyuan district of Taiyuan city, China, to assess the accumulation risk of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn). The results were then integrated, and source apportionment was evaluated by geospatial analysis, multivariate statistical analysis and positive matrix factorization (PMF). Cr, Cd and Hg were the dominant pollutants in the studied area. Accumulation risk by Cd and Cu was more severe in greenhouse fields than in dry land or paddy fields, whereas As, Hg and Pb had relatively higher accumulation in paddy fields than in dry land or greenhouse fields. Hg was derived mainly from coal combustion by atmospheric precipitation for the three types of farmland. Long-term irrigation using sewage is the main reason for the accumulation of Cu and Ni in dry land soil, Cu and Zn in paddy field soil and Zn in greenhouse soil. Cd in dry land, Cd and Pb in paddy fields and Cd, Cu, Ni and Pb in greenhouse fields were primarily added to soil through fertilization. Sewage irrigation and fertilization were the dominant sources of heavy metals for paddy field (31.3%) and greenhouse field (33.1%), respectively.

A risk-based approach for the safety analysis of eight trace elements in Chinese flowering cabbage (Brassica parachinensis L.) in China

BACKGROUND

Most countries set regulatory values for the total trace element (TE) concentrations in soil, although there is growing interest in using a risk-based approach to evaluate the bioavailable TE using dilute salt extractants or other soil parameters, including pH and organic carbon_. The present study compares the current regulatory system (based on total TEs and pH) and a risk-based approach using 0.01 mol L^-1 CaCl₂ to estimate the bioavailable fraction.

RESULTS

In total, 150 paired samples of Chinese flowering cabbages (Brassica parachinensis) and their growth soils were collected, and the total and extractable concentrations of chromium (Cr), cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As) and mercury (Hg), as well as soil pH and organic matter content, were measured. No more than 3.33% of the edible parts exceeded Chinese food safety standards, even when growing in soils exceeding the current regulatory thresholds by over 50%. The total soil Cd (1.5 mg kg^-1 ), as well as the extractable concentrations of Cd (0.1 mg kg^-1 ), Ni (0.03 mg kg^-1 ) and Zn (0.1 mg kg^-1 ), are the key factors affecting the TE concentrations in B. parachinensis.

CONCLUSION

Our findings suggest that the current soil regulatory guidelines for safe production of B. parachinensis are overly strict and conservative. A risk-based approach based on the extractable TE concentrations would provide a better indication for plant uptake of soil TEs and avoid the waste of farmlands that can still produce safe vegetables. Future research should focus on providing crop-specific available TE concentration guidelines to promote effective utilization of farmlands. © 2021 Society of Chemical Industry.

Appraisal of pollution of potentially toxic elements in different soils collected around the industrial area

It is imperative to understand the pollution of potentially toxic elements (PTEs) in different soils in order to determine the sustainable management approaches for soils. Potentially toxic elements (Fe, Mn, As, Pb, Zn, Ni, Cu, Cr, Co and Cd) were determined in agricultural, non-agricultural and industrial soils of Punjab, India. The concentration of PTEs at industrial soils were highest followed by non-agricultural and agricultural soils. The percentage change recorded from agricultural to non-agricultural soils for PTEs were 3.19% for Fe, 25.3% for Mn, 63.8% for Cu, 13.5% for Cr, 49.8% for Pb, 79.6% for Ni, 35.8% for Co and 32% for Cd. From non-agricultural to industrial soils, the percentage change observed for PTEs were 89% for Zn, 2.03% for Fe, 21.9% for Mn, 68.2% Cu, 9.2% for Cr, 35.8% for Pb, 18.4% for Co, 30.4% for Cd and 43.4% for As. The results of contamination factor, enrichment factor, geo-accumulation index, pollution and modified pollution indices also resulted severe contamination of Cd and As in all soil types. Ecological risk assessment results revealed that Cd exhibited very high risk in different soil types. The outcomes of this study will aid in forming approaches to decline the perils allied with PTEs in soils, and produce guidelines to save the environment from long term accrual of PTEs.

Migration behavior of radiostrontium and radiocesium in arid-region soil

The time-dependent of the average migration, depths and migration rates of radiostrontium and radiocesium were experimentally determined in sandy soil in Kuwait. The study aimed to describe the behavior of these radionuclides in typical soil types in Kuwait. Custom-made large-diameter lysimeters (30 cm) were constructed to hold about 70 kg of undisturbed soil. The top surface soil was contaminated with known activity concentrations of ⁸⁵Sr and ¹³⁴Cs radionuclides. The topsoil was wetted with 1 L of water weekly using a rain simulator tool. Gamma scanning of the lysimeters in a step of 5 cm from three sides was performed at three measurement times by a high-resolution portable gamma spectrometry system. The vertical distribution pattern of ⁸⁵Sr and ¹³⁴Cs concentration exhibited an exponential trend. The average migration depth and migration rates were calculated, and 90% of the ⁸⁵Sr and ¹³⁴Cs were situated at 10.38 and 5.73 cm in the topsoil layer, respectively. The average vertical migration rate of ⁸⁵Sr varied from 2.2 to 4.4 cm y^-1, and ¹³⁴Cs was from 0.3 to 0.9 cm y^-1. It was demonstrated that the mobility of the ⁸⁵ Sr and ¹³⁴ Cs in the sandy soil could be attributed to the physicochemical properties of the radionuclide, in particular the distribution coefficient (Kd). The obtained results could be adopted by the regions of similar climatological conditions, especially, the gulf countries region when the radiological risk assessment of contaminated sites and dose estimation is required.

Ecological risk assessment and source apportionment of heavy metals contamination: an appraisal based on the Tellus soil survey

It is imperative to comprehend the level and spatial distribution of soil pollution with heavy metals to find sustainable management approaches for affected soils. Selected heavy metals (Mn, Zn, Pb, Cu, Cr, Ni, As, Co, and Cd) and physiochemical parameters were appraised for 620 samples from industrial, agricultural and urban sites in Northern Ireland using the Tellus database. The findings of this study showed that among the analyzed heavy metals, Mn content was the highest and Cd content the lowest. Pearson's correlation analysis revealed that heavy metals were highly correlated with each other, signifying similar sources for the heavy metals. Mixed factors (anthropogenic and lithogenic) were responsible for the contribution of heavy metals as revealed by multivariate statistical analysis. The results of contamination factor and enrichment factor analyses suggest that As, Cd, and Pb showed very high risk for pollution in the study area. The geoaccumulation index revealed that with the exception of Cd, all analyzed heavy metals showed severe accumulation in the soils. The potential and modified ecological risk indices inferred that Cd, As, and Pb represented ecological threats in the soils of Northern Ireland. The findings of this study will aid in forming approaches to decrease the risks associated with heavy metals in industrial, urban and agricultural soils, and help create guidelines to protect the environment from long-term accumulation of heavy metals.

Advanced Rainfall Trend Analysis of 117 Years over West Coast Plain and Hill Agro-Climatic Region of India

In this paper, the rainfall trend of the West Coast Plain and Hill Agro-Climatic Region is analyzed for 117 years (1901–2017). This region is a globally recognized biodiversity hotspot and known for one of the highest rainfall receiving regions in India. Rainfall grid dataset is used for the analysis of rainfall trends on monthly, seasonal, and decadal time scales. Modified Mann–Kendall’s test, Linear Regression, Innovative Trend Analysis, Sen’s Slope test, Weibull’s Recurrence Interval, Pearson’s Coefficient of Skewness, Consecutive Disparity Index, Kurtosis, and some other important statistical techniques are employed for trend analysis. Results indicate that the rainfall trend is significant in January, July, August, September as well as the Winter season. Among all the significant trends, January and July showed a decreasing rainfall trend. July has the highest contribution (30%) among all the obtained monotonic trend to annual rainfall and coincidentally has the highest trend magnitude. August and September months with a combined contribution of 30% to annual rainfall, show an increasing monotonic trend with high magnitude whereas Winter season shows a monotonic decreasing rainfall trend with comparatively low magnitudes. Decadal analysis along with the study of recurrence interval of excess and deficit years helps to understand the decadal rhythm of trend and the magnitude of extreme monthly and seasonal events. Skewness reveals that rainfall dataset of all the periodic results is right-skewed and the recurrence interval also supports the skewness results. Sharply decreasing rainfall in July and rising rainfall in August and September is predictive of the impact on agriculture, biodiversity and indicates the rainfall regime shift in the region.