Selenium Content In Soil Research Articles

Selenium status of urban residents on the territory of the Crimean peninsula

Introduction. Considering the essential biological role of selenium, including its role in preventing cardiovascular diseases and its widespread deficit in soils, assessing selenium status for Crimean region inhabitants is an actual task. Material and methods. Determination of selenium content in hair as index the of long-term element’s intake into the human body by all pathways were determined by the fluorometric method in 46 inhabitants (18-20 years old) from city Simferopol. Additionally, the selenium was determined in water and food products in Simferopol and nearby residential territories. Results. Selenium content in most residents’ hair varied from 210 to 309 mcg/kg and 12-40% less than the normal range’s lower limit. These results show the selenium deficiency in urban residents from the Crimean region, mainly due to the low content of this element in cereal products and, to a less degree, - in water. However, most food products, which are the primary source of selenium in Crimean inhabitants’ diet, are delivered from other Russian regions. So it’s possible to assess the selenium supply of inhabitants, but it is not possible to make a total conclusion about the selenium status of the region. Conclusion. The revealed deficiency of selenium in Crimean region inhabitants and the literature data about the positive and close relationship between hyposelenosis and the quality of public health requires the extensive monitoring of the selenium content in soils and crop production the Crimean peninsula territory.

Characteristics and source of soil selenium content in Zhangba Village, Lintong District, Shaanxi Province

Soil selenium content affects the absorption and accumulation of selenium in crops and ultimately affects human health; therefore, it is of great significance to study the characteristics of selenium content in soils and crops. Based on the previous agricultural geological survey and research carried out in Lintong area, and combined with data of Second National Land Survey, the agricultural geological survey and evaluation at the village level was carried out in Zhangba Village, Lintong District. Distribution characteristics of soil selenium content in each plot and selenium levels in crops were analyzed systemically, and the causes and influence factors of soil selenium was preliminarily studied. This survey found that selenium content of the soils and crops in Zhangba Village all met the standard of selenium enrichment. This finding provides strong support for land resource planning and management and rational utilization of selenium-rich soil resources in this area, moreover, it is of great significance to adjust planting structure, improve land use value, and promote development of selenium-rich agriculture.

Selenium and cancer or adenoma related to the large bowel*

Summary The protective effect of selenium against colorectal cancer or adenoma is still a controversial issue. Although there are well-described (pato)physiological protective mechanisms of selenium against colorectal cancer, the results of the studies from 1998–2018 are inconclusive and need to be considered in the future. Neither observational nor experimental studies present consistent results. Although the Cochrane review showed that well-designed randomized clinical trials (RCTs) presented no beneficial effect of selenium supplementation on cancer incidence, well-designed RCTs confirming the protective effect of selenium supplementation against colorectal adenoma or colorectal polyp recurrence have been found in subject-related literature. In the reviewed studies, selenium concentration was measured in the blood serum/toenail or in diet. It is of great importance to highlight that blood selenium concentration depends on the concentration of this micronutrient in food, which in turn depends on selenium content in soil, bioavailability of selenium, which is different in various geographical regions, and forms of selenium. Selenium circulating in blood as a component of selenoproteins participates in oxidoreduction, thus reducing the risk of developing colorectal cancer. Despite this well-known protective mechanism against colorectal cancer occurrence, half of the reviewed studies did not confirm the protective properties of selenium. To sum up, the current state of knowledge on the association between selenium and colorectal cancer or adenoma has revealed not only inconclusive results of the studies, but has also shown that there is a need to conduct more prospective studies focused on selenium supplementation and colorectal cancer as this research is limited.

Soil Selenium Concentration and Residents Daily Dietary Intake in a Selenosis Area: A Preliminary Study in Yutangba Village, Enshi City, China.

In 1963, selenosis occurred in Yutangba Village, Enshi City, China. Subsequently, local residents migrated to a new area of Yutangba to avoid high selenium (Se) exposure. In this study, 19 soil samples, 43 food samples, 60 hair samples and 58 plasma samples from local residents were randomly collected in New Yutangba Village. The mean total Se concentrations in cultivated soil samples were 1753.6 ± 742.8µg/kg (n = 14). The estimated daily Se intake in New Yutangba Village decreased to 63.2 ± 39.8µg/day, slightly higher than the recommended dietary Se intake for adults in China (60µg/day). The mean Se concentrations in hair and plasma samples were 549.7 ± 165.2µg/kg (n = 60) and 98.4 ± 32.1µg/L (n = 58), respectively. The result indicated that appropriate activities, such as relocation, consuming a mixture of local foods and market foods containing low Se concentration, could effectively reduce the risk of high Se exposure.

Distribution characteristics and main influencing factors of selenium in surface soil of natural selenium-rich area: a case study in Langao County, China.

In order to study the distribution of selenium in surface soil and its main influencing factor, we collected 360 surface soil samples and four groups of soil profiles with 210 corresponding parent rock samples in Langao County, Shaanxi Province (a typical high-selenium area of Daba Mountain). Samples were analyzed for trace elements by using ICP-MS, ICP-OES and HG-AFS. The results show the following. (1) selenium content in surface soils of Langao County varies greatly (0.03-16.96mg/kg). The mean selenium content in surface soils of Langao County is 0.99mg/kg, higher than the global (0.4mg/kg) and China (0.29mg/kg) soil average, and 3.4 times the mean of soil selenium in China. (2) Selenium content of bedrock in Langao County also varies greatly (0.01-56.22mg/kg), with an average selenium content of 2.02mg/kg, which is 40 times higher than the upper crust (0.05mg/kg). (3) Selenium content in the strata of the Late Precambrian-Early Paleozoic and its variation is an important factor affecting the spatial variation of soil selenium content. The black rock series (carbonaceous slate and silicon-bearing carbonaceous slate) of the Upper Ediacaran-Cambrian on the north side has the highest mean selenium content (> 7.92mg/kg), and the selenium content of the surface soil in the distribution area can reach up to 16.96mg/kg. The Middle Cambrian, Upper Cambrian, Ordovician and Silurian (limestone and marl) in the south has the lowest mean selenium content (< 2mg/kg), and the selenium content of surface soil in the distribution area is lower than 0.8mg/kg mostly. (4) Soil samples at different depths in the same soil profile have similar composition of rare earth elements (REE), and bedrock and corresponding topsoil has similar composition of REE. This study indicates the selenium content in the topsoil varies greatly, even in high-selenium area. And the difference of selenium distribution is closely related to the original selenium content of the bedrock.

Relationship Between Metal Load (Selenium, Arsenic, Molybdenum) of Soil, Plant and Serum of Buffaloes

Presence of hazardous minerals in three major components (soil, forage and buffalo serum) was evaluated for determining extent of metal contamination in Sargodha, Pakistan. Ten soil and forage samples for each season were taken from ten randomly selected sites. 30 grazing buffaloes of �niliravi� breed (calves, non-lactating and lactating) were also sampled randomly from these sites for collection of serum. Heavy metal quantification via atomic absorption spectrophotometry was carried out for selenium, molybdenum and arsenic. Non-significant but positive correlation was found for selenium (Se) concentrations in soil, forage and serum and molybdenum (Mo) concentrations in soil and serum. Negative correlation (p]0.05) was obtained for Mo level between forage-serum and soil-forage which was indicative of molybdenum deficiency in the soil. The results suggested that the heavy metals remained below maximum permissible levels and were non-toxic for the ruminants of the study area.

Selenium Content in Soil and Wheat Grain in Bulgaria

Selenium Content in Soil and Wheat Grain in Bulgaria

Distribution, origin and speciation of soil selenium in the black soil region of Northeast China.

Selenium (Se) is an essential trace element within human beings that hold with crucial biological functions. Investigating the complex origin of soil Se is of great importance to scientifically approach the land use of Se-rich land use, and the respective promotion of regional economic development. In this study, 160 soil samples from 10 profiles in farmland and woodland were collected in Hailun city, which is a typical black soil region in Northeast China, in order to characterize the distribution and speciation of Se in the black soil, and to identify the origin of soil Se. The total selenium content in the soil ranges from 0.045 to 0.444μgg-1, with an average selenium content in black soil (0.318μgg-1) of three times greater than that found in the yellow-brown soil (0.114μgg-1). The land-use type has a significant influence on the distribution of selenium in the black soil. Moreover, Se and heavy metals have a significant (positive or negative) correlation, in which TOC plays an important role. The black soil presents a consistent REE distribution pattern with underlying yellow-brown soil indicating black soil originates from yellow-brown soil. REE geostatistical analysis suggests that the soil Se partly originates from shale weathering and enriches in black soil. Moreover, elemental geochemical analysis and XRD results show that the paleoclimate change from humid and warm to dry and cold is favorable for organic matter accumulation, resulting in less leaching and enhanced adsorption of selenium into the black soil.

Selenium content in Bg 350 variety of rice consumed by Sri Lankans

Selenium is considered as an essential micronutrient. The daily requirement of selenium is 55 µg. As a result, the World Health Organization (WHO) has drawn their attention to establish the micronutrient range of selenium, required by the human body. Report from China has shown that an ecological correlation exists with the selenium content in the soil and increased mortality due to cancer and cardiovascular diseases with light intake of selenium. This led to the interest in assessing the nutritional status of selenium. Rice is the staple food of Sri Lankans and studies on selenium content in rice grown in Sri Lanka have not been reported. The present study reports the selenium content in Bg 350 variety of rice and soil obtained from twelve districts (Gampaha, Colombo, Matara, Hambantota, Kegalle, Matale, Anuradhapura, Pollanaruwa, Kurunegalle, Puttalam, Ampara and Moneragalle), in Sri Lanka determined using Hydride Generation Atomic Absorption spectrometer (HGAAS). The results of the study showed that selenium content in rice and soil obtained from Gampaha and Colombo districts were very low and less than the detectable levels of the instrument (0.5 μg/kg). Except for rice and soil from Pollanaruwa district that had a very high selenium content in rice (61.2 μg/kg) and soil (69.8 μg/kg), the respective values from other districts were low [13.8 μg/kg (Kegalle) -6.3 μg/kg (Anuradhapura)] and [20.3 μg/kg (Matara) -9.5 μg/kg (Matale)].

Assessing controls on selenium fate and transport in watersheds using the SWAT model

Selenium toxicity in groundwater and surface water in many regions globally has resulted in toxicity in the food chain thus harming terrestrial and aquatic animals. Here we assess the environmental controls on selenium fate and transport in soils, groundwater, and rivers at the watershed scale using the SWAT watershed simulation model. We modify the SWAT modeling code to simulate selenium fate and transport in surface runoff, lateral flow, soil percolation, groundwater flow, streamflow, and irrigation water within a watershed subject to oxidation-reduction reactions. This modified SWAT model is applied to an irrigated watershed with selenium problems in the Arkansas River Valley, Colorado. The model is calibrated and tested using observed groundwater and surface water selenium data in different locations of the study area, whereupon global sensitivity analysis is performed to assess controls on selenium fate and transport in soil water, groundwater and streams. The impacts of reaction rates of selenate, selenite, oxygen and nitrate along with 14 hydrologic parameters are assessed. For the baseline model, selenium loading to streams during growing season is mostly via groundwater discharge (365 kg/ha; 85% of total), followed by surface runoff (14%), and soil lateral flow (1%), which are about 4-fold the loading that occurs during non-growing season. Results from the sensitivity analysis indicate that hydrologic factors (timing of recharge, soil hydraulic conductivity, and groundwater storage thresholds) are the principal controls on selenium content in soils, groundwater, and stream water, followed by the first-order reaction rates of selenate and selenite, amount of selenium-bearing shale in the aquifer, and sulfur to selenium ratio in the shale material. These results suggest that selenium mitigation procedures should focus on water management practices rather than influencing microbial redox reactions. Overall, the SWAT-Se model introduced here can be used to assess Se contamination and mitigation practices in watersheds worldwide.

Association between Selenium in Soil and Diabetes in Chinese Residents Aged 35–74 Years: Results from the 2010 National Survey of Chronic Diseases and Behavioral Risk Factors Surveillance

ObjectiveTo explore the association between soil selenium levels and the risk of diabetes in Chinese adults aged 35–74 years. MethodsData for this study were derived from the China Chronic Diseases and Behavioral Risk Factors Surveillance 2010 survey. Selenium concentrations in soil were obtained from the Atlas of Soil Environmental Background Values in China. A two-level binary logistic regression model was used to determine the association between soil selenium concentrations and the risk of diabetes, with participants nested within districts/counties. ResultsA total of 69,332 participants aged 35–74 years, from 158 districts/counties were included in the analysis. Concentrations of selenium in soil varied greatly across the 158 districts/counties, with a median concentration of 0.219 mg/kg (IQR: 0.185–0.248). The results showed that both Quartile 1 (0.119–0.185 mg/kg) and Quartile 4 (0.249–0.344 mg/kg) groups were positively associated with diabetes compared to a soil selenium concentration of 0.186–0.219 mg/kg (Quartile 2), crude odds ratios (ORs) (95% CI) were 1.227 (1.003–1.502) and 1.280 (1.048–1.563). The P values were 0.045 and 0.013, for Quartile 1 and Quartile 4 groups, respectively. After adjusting for all confounding factors of interest, the Quartile 1 group became non-significant, and the Quartile 4 group had an adjusted OR (95% CI) of 1.203 (1.018–1.421) relative to the reference group (Quartile 2), the P values was 0.030. No significant results were seen for the Quartile 3 group (0.220–0.248 mg/kg) compared to the reference group. ConclusionExcessive selenium concentrations in soil could increase the risk of diabetes among Chinese adults aged 35–74 years.

Environmental and field characteristics associated with lameness in sheep: a study using a smartphone lameness app for data recording

BackgroundSheep lameness is a major concern among farmers and policymakers with significant impacts on animal welfare standards as well as financial and production performance. The present study attempts to identify...

Ecological and Physiological Patterns of Selenium Migration within the Volga River Ecosystem

The article presents the results of selenium migration analysis within river ecosystem. Maximal concentration of selenium was observed near Tomakovsky and Nazarovsky ravines within Saratov territory. The concentration of this microelement at the right river bank was slightly higher than at the left bank. The concentration of selenium in bottom soil ranged from 0.062–0.099 μg/g. Maximal concentration of microelement was found in clasping-leaved pondweed. Selenium concentration in fish bodies depends on their species and nutrition. Maximal concentration of microelement was found in crucian carps, and minimal – in rudds.

Exposure to a high selenium environment in Punjab, India: Effects on blood chemistry.

Many studies have shown that overexposure to environmental selenium may exert a wide pattern of adverse effects on human health, but much uncertainty still surrounds some of them as well as the exact amounts of exposure involved. In particular, very few studies have addressed the possible changes in blood chemistry following high selenium exposure. In a Northeastern part of Punjab, India, very high soil selenium content has been documented, with a value exceeding 2mg/kg (up to 5) as compared with the <0.5mg/kg selenium content characterizing the surrounding referent areas. In seven villages located in that seleniferous areas, we carried out a survey by recruiting volunteers and sampling blood, hair and nail specimens. We administered a questionnaire to the participants and analyzed the specimens for the selenium, along with a series of biochemical and haematological parameters in blood. We included 680 adult volunteers (267 men and 413 women), who showed median selenium levels of 171.30µg/L in serum, 1.25µg/g in hair, and 5.7µg/g in nails. Overall, increasing selenium exposure tended to correlate with higher levels of total cholesterol, albumin, free triiodothyronine, deionidase activity, and with red cell and platelet counts. After stratifying the subjects according to category of selenium exposure, we observed a dose-response relation between serum selenium and risk of high total cholesterol, and between hair selenium and risk of high total and low-density lipoprotein cholesterol, high pancreatic lipase, altered thyroid-stimulating hormone and free triiodothyronine levels. Nail selenium exposure category positively correlated with risk of high alanine-aminotransferase, altered albumin levels, high pancreatic lipase and low levels of thyroid-stimulating hormone. Chronic selenium overexposure appears to adversely affect lipid profiles and pancreatic, liver, and thyroid function, with selenium biomarkers having different abilities to predict such effects.

Selenium enhances antioxidant capacity by improving dencichine content in Panax notoginseng

Dencichine is the main ingredient in Panax notoginseng, which is an herb that plays a key role in hemostasis. The biosynthesis of dencichine requires the participation of sulfur. Selenium and sulfur are congeners. The purpose of this study was to reveal if selenium participates in the synthesis of dencichine, and to determine whether dencichine plays a role in anti-stress effects. P. notoginseng and planting soil were sampled from different sites and subjected to selenium and dencichine determinations. Biosynthesis of dencichine was investigated by exposing the seedlings to different selenium concentrations in pot and hydroponic experiments. The effects of dencichine on the regulation of the antioxidant enzyme system and reactive oxygen species (ROS) were also tested in hydroponic experiments. The results indicated that the selenium and dencichine contents of roots were 0.69-0.98% and 0.21–1.18 mg kg−1, respectively, and the soil selenium content in 18 planting areas in Yunnan Province was 0.16-0.32 mg kg−1. Dencichine and selenium contents in soil or plants were positively correlated (R2 = 0.1643***, R2 = 0.3084***, respectively). Selenium treatment increased the dencichine content by 69–111% in pot experiments using 5 mg kg−1 and by 23–33% in hydroponic experiments using 2 μM. The key genes in the dencichine biosynthetic pathway, such as β-cyanoalanine synthase and serine acetyltransferase, were significantly upregulated by the 2 μM selenium treatment. Dencichine treatment (30 μM) significantly enhanced root activity, increased antioxidant capacity, decreased ROS content, and reduced lipid peroxidation of the cell membranes. Therefore, selenium promoted the synthesis of dencichine, which acted as an anti-stress agent in P. notoginseng. However, the selenium content was deficient in the P. notoginseng planting soil from Yunnan Province. These results suggest that appropriate selenium supplementation is beneficial for the growth and development of P. notoginseng and the accumulation of dencichine.

Spatial Variation of Human Selenium in Ethiopia.

Selenium is an important nutrient for humans and livestock. Soil selenium concentration in the world is highly variable; deficiency and toxicity occur in populations living short distance apart. Knowledge of Se concentrations in humans and the environments, especially because the range for toxicity and deficiency is narrow, is important for effective intervention. Dietary data and serum samples were collected from children (n = 555) 69-78months old from rural villages of the Amhara Region, Ethiopia. In addition, information on the socio-demography of households was collected. Serum Se was analyzed by inductively coupled plasma mass spectrometer. Almost all (90.3%) of participants reported eating grain, roots, or tubers 24h preceding the survey followed by legumes, nuts, and seeds (64.6%). Consumption of animal source foods was very low (4.6%). Compared to children from the western part of the region, children from eastern Amhara had higher dietary diversity score (2.1 ± 0.9 vs 1.8 ± 0.7; p < 0.001).The median serum Se concentration was 70.6μg/l (IQR 48.2, 96.6). Selenium inadequacy (serum Se < 70μg/l) was detected in 49.1% of children. However, the distribution had an important geographical pattern across administrative zones. Children from the western part of the Amhara Region were highly deficient (up to 91.1% prevalence), while there was little or no Se deficiency in children from the eastern part of the region. Serum Se level exhibited an important spatial variation in the Amhara Region, Ethiopia. Further studies investigating contributing factors for the variation such as soil characteristics and Se concentration in staple crops are needed.

Зависимость содержания селена в почве и кормах от уровня Hg, Pb, Cd, являющихся его антагонистами

Зависимость содержания селена в почве и кормах от уровня Hg, Pb, Cd, являющихся его антагонистами

Effects of different water management on absorption and accumulation of selenium in rice

Rice is the staple food for more than half of the world's population, but selenium (Se) is low in many rice growing countries. Water management model affects rice soil pH and Eh, and then affects the bioavailability of Se in soil. A pot experiment was conducted to investigate the effects of water management on soil Se species, dynamics and selenium uptake by rice plants. Sodium selenite was added to the soil so that the soil selenium content reached 0.5 mg kg−1 to study the effects of 3 different water management modes on soil selenium uptake by rice plants. These three modes are flood irrigation (F), aerobic irrigation (A) and alternate flood and aerobic irrigation (AFA). The results showed that flooded irrigation treatment increased the soil soluble selenium concentration, and the selenium in soil solution mainly existed in the form of selenite and selenomethionine selenium oxide. The content of selenium in grain was 2.44 and 1.84 times that of flooded irrigation treatment under A and AFA respectively. The content of selenium in straw was 1.32 and 1.58 times that of flooded treatment under A and AFA respectively. After rice grain enzyme hydrolysis, HPLC-ICP-MS analysis showed that Selenomethionine was the main selenium speciation in rice grains. This study showed that aerobic flooded treatment is one of the most effective ways to increase selenium content in rice field.

The impact of land use on the organic and inorganic selenium content in soils developed from loess

The impact of land use on the organic and inorganic selenium content in soils developed from loess

Associations of Spatial Disparities of Alzheimer's Disease Mortality Rates with Soil Selenium and Sulfur Concentrations and Four Common Risk Factors in the United States.

Associations between environmental factors and spatial disparity of mortality rates of Alzheimer's disease (AD) in the US are not well understood. To find associations between 41 trace elements, four common risk factors, and AD mortality rates in the48 contiguous states. Isopleth maps of AD mortality rates of the 48 states and associated factors were examined. Correlations between state average AD mortality rates and concentrations of 41 soil elements, wine consumption, percentage of current smokers, obesity, and diagnosed diabetes of the 48 states between 1999 and 2014 were analyzed. Among 41 elements, soil selenium concentrations have the most significant inverse correlations with AD mortality rates. Rate ratio (RR) of the 6 states with the lowest product of soil selenium and sulfur concentrations is 53% higher than the 6 states with the highest soil selenium sulfur product in the 48 states (RR = 1.53, CI95% 1.51-1.54). Soil tin concentrations have the most significant inverse correlation with AD mortality growth rates between 1999 and 2014, followed by soil sulfur concentrations. Percentages of obesity, diagnosed diabetes, smoking, and wine consumption per capita also correlate significantly with AD mortality growth rates. High soil selenium and sulfur concentrations and wine consumption are associated with low AD mortality rates. Given that average soil selenium and sulfur concentrations are indicators of their intakes from food, water, and air by people in a region, long-term exposure to high soil selenium and sulfur concentrations might be beneficial to AD mortality rate reduction in a region.