Biomonitoring of mercury and selenium in commercially important shellfish: Distribution pattern, health benefit assessment and consumption advisories.

This study aims to explore the concentrations of Se and Hg in shellfish along the Gulf of Mannar (GoM) coast (Southeast India) and to estimate related risks and risk-based consumption limits for children, pregnant women, and adults. Se concentrations in shrimp, crab, and cephalopods ranged from 0.256 to 0.275 mg kg-1, 0.182 to 0.553 mg kg-1, and 0.176 to 0.255 mg kg-1, respectively, whereas Hg concentrations differed from 0.009 to 0.014 mg kg-1, 0.022 to 0.042 mg kg-1 and 0.011 to 0.024 mg kg-1, respectively. Se and Hg content in bamboo shark (C. griseum) was 0.242 mg kg-1 and 0.082 mg kg-1, respectively. The lowest and highest Se concentrations were found in C. indicus (0.176 mg kg-1) and C. natator (0.553 mg kg-1), while Hg was found high in C. griseum (0.082 mg kg-1) and low in P. vannamei (0.009 mg kg-1). Se shellfishes were found in the following order: crabs > shrimp > shark > cephalopods, while that of Hg were shark > crabs > cephalopods > shrimp. Se in shellfish was negatively correlated with trophic level (TL) and size (length and weight), whereas Hg was positively correlated with TL and size. Hg concentrations in shellfish were below the maximum residual limits (MRL) of 0.5 mg kg-1 for crustaceans and cephalopods set by FSSAI, 0.5 mg kg-1 for crustaceans and 1.0 mg kg-1 for cephalopods and sharks prescribed by the European Commission (EC/1881/2006). Se risk-benefit analysis, the AI (actual intake):RDI (recommended daily intake) ratio was > 100%, and the AI:UL (upper limit) ratio was < 100%, indicating that all shellfish have sufficient level of Se to meet daily requirements without exceeding the upper limit (UL). The target hazard quotient (THQ < 1) and hazard index (HI < 1) imply that the consumption of shellfish has no non-carcinogenic health impacts for all age groups. However, despite variations among the examined shellfish, it was consistently observed that they all exhibited a Se:Hg molar ratio > 1. This finding implies that the consumption of shellfish is generally safe in terms of Hg content. The health benefit indexes, Se-HBV and HBVse, consistently showed high positive values across all shellfish, further supporting the protective influence of Se against Hg toxicity and reinforcing the overall safety of shellfish consumption. Enhancing comprehension of food safety analysis, it is crucial to recognize that the elevated Se:Hg ratio in shellfish may be attributed to regular selenoprotein synthesis and the mitigation of Hg toxicity by substituting Se bound to Hg.

Selenium and mercury concentration, Se/Hg molar ratio and risk-benefit assessment of marine fish consumption: Human health risks and protective role of Se against Hg toxicity.

This study aimed to explore the concentrations of Se and Hg in marine fish along the Gulf of Mannar (southeast coast of India) and to assess related risks and risk-based consumption limits for children, pregnant women, and adults. Se concentrations in pelagic and benthic fish ranged from 0.278 to 0.470 mg/kg and 0.203 to 0.294 mg/kg, respectively, whereas Hg concentrations ranged from 0.028 to 0.106 mg/kg and 0.026 to 0.097 mg/kg, respectively. Se and Hg contents in demersal fish (Nemipterus japonicus) were 0.282 and 0.039 mg/kg, respectively. The lowest and highest Hg concentrations in pelagic fish were found in Scomberomorus commersoni and Euthynnus affinis whereas the lowest and highest Se concentrations in benthic fish were found in Scarus ghobban and Siganus javus. Se concentrations in marine fishes were found in the following order: pelagic > demersal > benthic whereas Hg concentrations were found in the following order: pelagic > benthic > demersal. The presence of Se in fish was positively correlated with trophic level (TL) and size whereas that of Hg was weakly correlated with TL and habitat and negatively correlated with size. Se risk-benefit analysis, the AI/RDI (actual intake/recommended daily intake) ratio was > 100 % and the AI/UL (upper limit) ratio was < 100 %, indicating that all fish have sufficient levels of Se to meet daily requirements without exceeding the UL. Hg level was below the maximum residual limit (MRL) of 0.5 mg/kg for most fish but it was 1 mg/kg in E. affinis and Lethrinus lentjan. The target hazard quotient (THQ < 1) and hazard index (HI < 1) imply that the consumption of fish poses no noncarcinogenic health risks. However, all examined fish had a mean Se/Hg molar ratio > 1, indicating that human intake of fishwas rather safe relative to Hg content. Health benefit indexes (Se-HBV and HBVse) with high positive values in all fish supported the protective effect of Se against Hg toxicity, suggesting the overall safety of fish consumption. The high Se/Hg ratio in fish could be attributed to the replacement of Se bound to Hg, thereby suppressing Hg toxicity and maintaining normal selenoprotein synthesis. This insight is useful for a better understanding of food safety analysis.

Integrative risk assessment method via combining geostatistical analysis, random forest, and receptor models for potentially toxic elements in selenium-rich soil.

Revealing the spatial features and source of associated potentially toxic elements (PTEs) is crucial for the safe use of selenium (Se)-rich soils. An integrative risk assessment (GRRRA) approach based on geostatistical analysis (GA), random forest (RF), and receptor models (RMs) was first established to investigate the spatial distribution, sources, and potential ecological risks (PER) of PTEs in 982 soils from Ziyang City, a typical natural Se-rich area in China. RF combined with multiple RMs supported the source apportionment derived from the RMs and provided accurate results for source identification. Then, quantified source contributions were introduced into the risk assessment. Eighty-three percent of the samples contain Cd at a high PER level in local Se-rich soils. GA based on spatial interpolation and spatial autocorrelation showed that soil PTEs have distinct spatial characteristics, and high values are primarily distributed in this research areas. Absolute principal component score/multiple line regression (APCS/MLR) is more suitable than positive matrix factorization (PMF) for source apportionment in this study. RF combined with RMs more accurately and scientifically extracted four sources of soil PTEs: parent material (48.91%), mining (17.93%), agriculture (8.54%), and atmospheric deposition (24.63%). Monte Carlo simulation (MCS) demonstrates a 47.73% probability of a non-negligible risk (RI > 150) caused by parent material and 3.6% from industrial sources, respectively. Parent material (64.20%, RI = 229.56) and mining (16.49%, RI = 58.96) sources contribute to the highest PER of PTEs. In conclusion, the GRRRA method can comprehensively analyze the distribution and sources of soil PTEs and effectively quantify the source contribution to PER, thus providing the theoretical foundation for the secure utilization of Se-rich soils and environmental management and decision making.

Dietary sources apportionment and health risk assessment for trace elements among residents of the Tethys-Himalayan tectonic domain in Tibet, China.

Dietary intake of toxic elements (TEs) and essential trace elements (ETEs) can significantly impact human health. This study collected 302 samples, including 78 food, 104 drinking water, 73 cultivated topsoil, and 47 sedimentary rock from a typical area of Tethys-Himalaya tectonic domain. These samples were used to calculate the average daily dose of oral intake (ADDoral) and assess the health risks of five TEs and five ETEs. The results indicate that grain and meat are the primary dietary sources of TEs and ETEs for local residents. The intake of manganese (Mn) and copper (Cu) is mainly from local highland barley (66.90% and 60.32%, respectively), iron (Fe) is primarily from local grains (75.51%), and zinc (Zn) is mainly from local yak meat (60.03%). The ADDoral of arsenic (As), Mn, Fe and Zn were found to be higher than the maximum oral reference dose in all townships of study area, indicating non-carcinogenic health risks for local residents. Additionally, lead (Pb) and nickel (Ni) in 36.36% townships, and Cu in 81.82% townships were above the maximum oral reference dose, while As posed a carcinogenic risk throughout the study area. The concentrations of As, mercury (Hg), Pb, Mn, Cu Fe and selenium (Se) in grains were significantly correlated with those in soils. Moreover, the average concentrations of As in Proterozoic, Triassic, Jurassic and Cretaceous was 43.09, 12.41, 15.86 and 6.22 times higher than those in the South Tibet shell, respectively. The high concentrations of TEs and ETEs in the stratum can lead to their enrichment in soils, which, in turn, can result in excessive intake by local residents through the food chain and biogeochemical cycles . To avoid the occurrence of some diseases caused by dietary intake, it is necessary to consume a variety of exotic foods, such as high-selenium foods, foreign rice and flour in order to improve the dietary structure.

Assessment of the Concentration of 51 Elements in the Liver and in Various Parts of the Human Brain-Profiling of the Mineral Status.

The anthropogenic environment and diet introduce many metals into the human body, both essential and toxic. Absorption leads to systemic exposure and accumulation in body fluids and tissues. Both excess and deficiency of trace elements are health hazards. The primary aim of the present study was to evaluate the concentration of 51 elements in liver samples and 11 selected brain regions obtained at post-mortem examination from a population of adults living in south-eastern Poland (n = 15). A total of 180 analyses were performed by inductively coupled plasma mass spectrometry in two independent replicates. The collected data show very high individual variability in the content of the investigated elements. Macroelements such as sodium, magnesium, phosphorus, potassium, calcium, iron, and zinc occurred in the highest concentrations and with the greatest statistically significant variations. Although the elemental content of the brain and liver differed significantly, the strongest positive correlation between liver and polus frontalis was observed for the essential element selenium (0.9338) and the strongest negative one for manganese (-0.4316) and lanthanum (-0.5110). The brain areas studied have different requirements for phosphorus, manganese, iron, and molybdenum. In addition, males had a significantly (p < 0.05) higher brain content of lanthanides and actinides than females. The results of this study show that the inhabitants of south-eastern Poland are exposed to a fairly uniform accumulation of aluminum and vanadium in the brain, which have the highest affinity to the thalamus dorsalis. This result proves that there is environmental exposure to these elements.

Ecological risk assessment of potentially toxic elements in selenium-rich soil with different land-use types.

Dashan Village area is one of the representative areas in China with high selenium concentration in the natural environment. A total of 133 topsoil samples have been collected in the Dashan Village area to explore the potential toxic elements (PTEs) background concentrations in soils under different land-use types for a comprehensive PTEs risk assessment (arsenic, cadmium, chromium, copper, mercury, nickel, lead, selenium and zinc). The results show that the geometric mean concentrations of As, Cr, Cu, Hg, Ni, Pb, Se and Zn found in the soil of the Dashan Village area were lower than the control standard for soil contamination risk in agricultural land. However, the geometric mean concentrations of Cd exceeded their corresponding standard values. For different land-use types, geometric mean concentrations of As, Cd, Cu, Hg, Ni and Pb in the arable soils were higher than in woodland soils and tea garden soils. Based on the potential ecological risk assessment, the woodland, arable and tea garden were at low-risk levels. Cadmium posed the highest ecological risk, while the other PTEs were of low risk in soils. Multiple statistical analyses and geostatistical analysis indicated that the concentrations of Cr, Ni, Pb, Cu, Zn and Se originated mainly from natural sources, while the concentrations of Cd, As and Hg could be influenced by anthropogenic activities. These results provide scientific support for the safe utilization and ecological sustainability of selenium-rich land resources.

Total Mercury and Selenium in wild Shrimp from Coastal Lagoons of Northwest Mexico: Human Health risk Assessment.

This study analyzed total mercury (THg), and selenium (Se) in edible tissues of white shrimp (Litopenaeus vannamei), blue shrimp (L. stylirostris) and brown shrimp (F. californiensis), from three states of the Northwest of Mexico in September and October 2017. Concentrations of THg and Se in the muscle were between 0.026 and 0.829 and 0.126-1.741 µg/g dry weight (dw), respectively. Significant differences were observed among Hg concentration of Sonora and Nayarit and among Se concentration of Sinaloa and Nayarit. In addition, the health risk assessment (HQ) in the three species of shrimp was between 0.550 and 0.607. All Se:Hg molar ratios were > 1 and positive HBVSe values that showed that shrimp from Northwest of Mexico does not represent a risk to human health.

Health risk assessment and metal contamination in fish, water and soil sediments in the East Kolkata Wetlands, India, Ramsar site.

East Kolkata Wetlands (EKW) is an important site for fish culture in sewage-fed areas, which are major receivers of pollutants and wastages from Kolkata. EKW is internationally important as the Ramsar site was declared on Aug 2002 with an area of 125 km2. EKW is a natural water body where wastewater-fed natural aquaculture has been practiced for more than 70 years. It is ecologically vulnerable due to the discharge of toxic waste through sewage canals from cities. Assessing the EKW to understand the inflow and load of the toxic metal (s) in fish, water, and sediments samples is essential. The field (samples collection from 13 sites) and lab (determination of toxic level of metals) based research were carried out to assess metal toxicity and health risk assessment in EKW. The levels of eighteen metals (18), namely Chromium, Vanadium, Cobalt, Manganese, Copper, Nickel, Zinc, Silver, Molybdenum, Arsenic, Selenium, Tin, Gallium, Germanium, Strontium, Cadmium, Mercury, and Lead, were determined using Inductively coupled plasma mass spectrometry (ICP-MS) in five fish tissues viz. muscle, liver, kidney, gill and brain, along with the water samples and soil sediments in 13 sampling sites. The bioaccumulation and concentration of metals in fish tissues, soil sediments, and water samples were well within the safe level concerning the recommendation of different national and international agencies except for a few metals in a few sampling sites like Cd, As, and Pb. The geoaccumulation index (Igeo) was also determined in the soil sediments, indicating moderate arsenic, selenium, and mercury contamination in a few sites. The contamination index in water was also determined in 13 sampling sites. The estimated daily intake (EDI), reference dose (RfD), target hazard quotient (THQ), slope factor and cancer risk of Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd, Pb and Hg from fish muscle were determined. Based on the results of the present investigation, it is concluded that fish consumption in the East Kolkata Wetland (EKW) is safe. The effects of bioaccumulation of metals in muscle tissue were well within the safe level for consumption as recommended by WHO/FAO.

Determination of heavy metals from Aloe vera by- product in golden mullet (Liza aurata); A consumer health risk assessment.

Heavy metals have become subject of concern in the recent years because of its potency to cause cardiovascular diseases and other toxic health effects. Therefore, this research was assumed to investigate the level of toxicity in terms of heavy metals accumulation in the fish samples and its benefits and risk for human consumers health and also evaluate the partial replacement of plant sources by canarian Aloe vera diets as a pure product or like a by-product on toxicological effects on the golden mullet (Liza aurata) fillet and whole body. In this study risks arising from fish metal content has been measured using various parameters as Estimated Daily Intake (EDI), Maximum Safe Consumption (MSCA), Target Hazard quotient (THQ), Hazard Index (HI) Carcinogenic risk of As (As- CR), the Value Selenium Health Benefit (Se HBV) and also the Nutritional Values has been evaluated. The results showed that all heavy metal levels in the fish tissue and diets were below the confirmed safe limits for consumption. In case of diets, it is obvious that with the exception of As, Hg, and Se, the presence of heavy or essential metals in both whole fish and raw fillet in golden grey mullet given experimental diets revealed that the whole fish had the highest concentration. Thus, it can be concluded that Aloe vera product and byproduct were in safety limits for fish and also for humans through food chain. Various risk and benefit assessment measures established by national and international authorities concluded that Liza aurata use was mostly safe.

Hydrochemical evaluation of groundwater quality and human health risk assessment of trace elements in the largest mining district of South Khorasan, Eastern Iran.

The groundwater resources of mining areas have been in a challenging condition in terms of metal pollution and human health. Therefore, this study investigated the concentration of cobalt (Co), molybdenum (Mo), selenium (Se), tin (Sn), and antimony (Sb) in groundwater samples (wells, qanats, and springs) in a heavily contaminated mining district, South Khorasan, Eastern Iran. Human health risk of the studied metals to target groups was assessed, and water quality of the studied groundwater was investigated in the study area. A total of 367 sampling sites (279 wells, 74 qanats, and 14 springs) in South Khorasan Province were selected to collect the groundwater samples from June to July 2020. Sampling was performed thrice for each sampling point, and hydrochemical parameters were evaluated using a portable multiparameter. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the metal concentrations. Results showed an order of Se > Mo > Sn > Co > Sb, and hazard index (HI) demonstrated a warning condition for south of South Khorasan (drinking application), southwest of South Khorasan (Irrigation application), and east and center of South Khorasan (drinking-irrigation application). Hydrochemical parameters showed a classification of "Na + K type" and "Mixed Ca-Mg-Cl type" with an overall group of "Na-Cl-HCO3" for sampled waters. Ficklin-Caboi diagram depicted a classification of "near-neutral low metal," and Schoeller diagram classified studied groundwater as "good" for drinking and irrigation consumptions and "Na-Cl" type based on ion balance diagram. Based on the correlation analysis, positive relationships were recorded among EC, TDS, Cl-, Na+, sulfate, Ca2+, salt, total hardness, Mg2+, ammonia, and K+ measured in the water samples. In essence, arid regions of the world greatly rely upon groundwater resources for drinking and irrigation consumptions, and mining districts with a heavy load of active mines can be a serious threat to the groundwater quality and human health.

Determination of some heavy metals levels in the meat of animal species (sheep, beef, turkey, and ostrich) and carcinogenic health risk assessment in Kurdistan province in the west of Iran.

Heavy metals accumulation in food products as a result of industrialization is one of the main potential threats to public health. This study was aimed to evaluate the concentrations of heavy metals in the meat of some prevalent farm animal species including sheep, beef, turkeys, and ostriches in Sanandaj (one of the strategic cities in Kurdistan province, Iran). In this study, the contents of some heavy metals (selenium, lead, cadmium, arsenic, cobalt, zinc, nickel, copper, and chromium) were assessed in 170 meat samples collected from meat distribution centers in Sanandaj, Kurdistan province. The ICP-MS method was used to assess the levels of these elements in the meat of beef, sheep, turkey, and ostrich as the main consumed meats in this region. Statistical analysis was performed by ANOVA and one-sample t-test, and the correlation coefficient of the concentrations of metals was also calculated. The results showed that there were no significant differences in the average contents of selenium, nickel, cobalt, and chromium among various meats (P > 0.05). However, the amounts of lead, cadmium, arsenic, zinc, copper, chromium, and nickel were meaningfully different to maximum permissible limits (MPL) (P < 0.05). In addition, a significant negative correlation was found between arsenic and selenium in meats. Except for cobalt, the concentrations of other metals were higher than MPL in the evaluated meats. Despite the target hazard quotient (THQ) for cadmium in sheep and beef meats being higher than their MPL (> 1), its target risk of cancer (TR) was acceptable. It can be concluded that monitoring and elimination of heavy metals pollution are essential because of their high accumulation in the meat of main farm animal species in Sanandaj, Kurdistan province.

Selenium in selenium-rich rice sold in China and risk assessment.

Selenium-rich rice samples of 52 brands were bought from supermarkets on line in China and analysed for Se with ICP-MS. The Se concentration of Se-rich rice in China ranged from 0.012 ± 0.001 to 0.558 ± 0.057 mg/kg with an average of 0.090 ± 0.092 mg/kg. Rice samples with Se concentrations below 0.04 mg/kg accounted for 36.5% of the total samples. Se concentrations between 0.04 and 0.3 mg/kg accounted for 61.6%. Taking the upper tolerable limit of 400 µg/d as the risk standard, the risk of selenium intake by selenium-rich rice was low and the risk index was far less than 100%. With the upper intake limit of 100 µg/d and the adequate intake of 70 µg/d as the risk standard, the maximum intake risk index was higher than 100%, indicating a certain risk in the consumption of selenium-rich rice.

Selenium and mercury balance in sea bream obtained from different living environments in Turkey: a risk assessment for the consumer health.

The selenium health benefit value (Se-HBV) is the criterion developed for revealing nutritional values or the risks related to mercury (Hg) toxicity which can emerge in relation to consumption of fish. In this study, the conditions of Se and Hg elements in the muscular tissues of sea bream (Sparus aurata) living in different environments in Mugla province were examined. In addition, a benefit/risk assessment was performed in terms of consumer health with the calculation of Se-HBV. In this context, muscular tissues of sea bream obtained from wild species (WS), offshore marine cages species (OS), and soil ponds species (SS) were dissolved with microwave wet digestion and the concentrations of Se and Hg (mg/kg wet weight) were determined by using inductively coupled plasma mass spectroscopy (ICP-MS). According to the obtained results, the highest mean Se level was determined in SS (0.43 ± 0.02 mg/kg) followed by WS (0.35 ± 0.03 mg/kg) and OS (0.34 ± 0.02 mg/kg). The highest mean Hg concentration was detected in WS (0.09 ± 0.02 mg/kg) followed by OS and SS as 0.05 ± 0.01 mg/kg respectively. As a result of risk assessment conducted with Se-HBV, positive values were determined for each one of three sea bream groups.

Heavy metal and essential elements in beers from turkey market: A risk assessment study.

In this study, the level of arsenic (As), lead (Pb) and cadmium (Cd) and also essential elements in beer samples consumed in Turkey were investigated using the inductively coupled plasma mass spectrometry (ICP-MS) method. The heavy metal-induced non-carcinogenic and carcinogenic risks were calculated. For essential elements, the calculated estimated daily intake of iron (Fe), copper (Cu), selenium (Se) and cobalt (Co) from beer consumption were compared with their toxicity reference values. Tukey post-hoc test showed that As was found at a significantly higher level when compared to Pb. Also, a significant correlation was found between As level and alcohol by volume percent. All samples had a hazard quotient and hazard index <1, indicating no non-carcinogenic risk from exposure to single or multiple heavy metals. Some samples exceeded the threshold limit of acceptable cancer risk for As in the high beer consumer group. This assessment showed that in addition to health implications based on the alcohol content of beer, there might be a carcinogenic risk associated with the heavy metals content of these beverages.

Health risk assessment of heavy metals contamination in selenium-enriched eggs.

This study aims to quantify the amount of selenium (Se) generally consumed in the Chinese diet via Se-enriched eggs, as well as the levels of lead (Pb), arsenic (As), cadmium (Cd), chromium (Cr), and mercury (Hg) in such eggs, and to assess the health risks associated with their consumption in China. As would be expected, Se was found to present significantly higher geometric mean levels in the Se-enriched eggs (0.464 mg/kg) than in normal eggs (0.304 mg/kg); however, Se concentrations were also closely related to the Cr and Pb in the eggs, with the Pb levels found to exceed the Chinese standard limit. Therefore, the quantity of Pb in Se-enriched eggs requires attention. According to estimated daily intake (EDI) evaluations of Se and heavy metals, levels were found to be highest via children for all metals in the eggs, In adults, the total target hazard quotient (TTHQ) for Se, Pb, Cd, As, Hg, and Cr contamination in eggs were calculated to be below the standard limit of 1, thus confirming that Se-enriched eggs may be considered safe for consumption by adults. However, the THQ of as was higher than 1 in the children aged of 2-4 years, and the TTHQ values were higher than 1 in boys aged 2-9 and girls aged 2-8, indicating a significant non-carcinogenic health risk due to the intake of maximum metals in the eggs samples. Thus, the safety of selenium-enriched eggs for children should be of wide concern. In conclusion, while Se-enriched eggs offer high levels of selenium, their health safety is concerning.

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 0.444 µg g-1, with an average selenium content in black soil (0.318 µg g-1) of three times greater than that found in the yellow-brown soil (0.114 µg g-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.

Multiple exposure pathways and health risk assessment of selenium for children in a coal mining area.

Selenium (Se) presents a dual role to human body, harmful or beneficial, depending on its concentration. The exposure to this element has been associated to coal mining. Health risk assessment allows estimating and evaluating the risks that environmental hazards pose to vulnerable groups of populations. The present study aimed to analyze the risk of exposure to Se through multiple exposure pathways in children living in Candiota city, where the largest coal reserve of Brazil is located. Data from previous environmental (air, soil, drinking water, and food) and population parameters (age, weight, and food intake) were used to assess the health risk, which was calculated with real values (extracted from the population) and fixed reference values, based on the USEPA recommendation. Most of the children had low health risk (HQ < 1); however, in the most conservative scenarios (higher Se values in the different matrices), there was a high health risk in both scenarios, using population data or the USEPA parameters. The mean HQ using reference values was twice higher than using real values. Se content in air, soil, and drinking water did not represent important average daily dose in both scenarios. While, food intake was a main source of Se exposure, contributing with 96.9% of total Se intake. The findings of this study reinforce the importance of food intake for exposure to Se and the difference between HQs using population measures and fixed parameters of the USEPA highlights the need for adaptations to local scenarios for a better dimensioning of toxicological risk management actions.

Assessment of selenium spatial distribution using µ-XFR in cowpea (Vigna unguiculata (L.) Walp.) plants: Integration of physiological and biochemical responses.

Low concentrations of selenium (Se) are beneficial for plant growth. Foliar Se application at high concentrations is toxic to plants due to the formation of reactive oxygen species (ROS). This study characterized Se toxicity symptoms using X-ray fluorescence (XRF) technique in response to foliar Se application in cowpea plants. Five Se concentrations (0, 10, 25, 50, 100 e 150 g ha-1) were sprayed on leaves as sodium selenate. The visual symptoms of Se toxicity in cowpea leaves were separated into two stages: I) necrotic points with an irregular distribution and internerval chlorosis at the leaf limb border (50-100 g ha-1); II) total chlorosis with the formation of dark brown necrotic lesions (150 g ha-1). Foliar Se application at 50 g ha-1 increased photosynthetic pigments and yield. Ultrastructural analyses showed that Se foliar application above 50 g ha-1 disarranged the upper epidermis of cowpea leaves. Furthermore, Se application above 100 g ha-1 significantly increased the hydrogen peroxide concentration and lipid peroxidation inducing necrotic leaf lesions. Mapping of the elements in leaves using the XRF revealed high Se intensity, specifically in leaf necrotic lesions accompanied by calcium (Ca) as a possible attenuating mechanism of plant stress. The distribution of Se intensities in the seeds was homogeneous, without specific accumulation sites. Phosphorus (P) and sulfur (S) were found primarily located in the embryonic region. Understanding the factors involved in Se accumulation and its interaction with Ca support new preventive measurement technologies to prevent Se toxicity in plants.

Benefit-risk assessment of dietary selenium and its associated metals intake in China (2017-2019): Is current selenium-rich agro-food safe enough?

Dietary consumption of selenium-rich agro-food is an effective way to avoid selenium deficiency diseases, however, over consumption of selenium-rich agro-food will result in potential risk of selenosis and problems with associated metals. In this study, we measured the concentrations of selenium and its associated metals in 2756 common and 4894 selenium-rich agro-food samples in 10 regions of China. We found that selenium-rich rice, flour, edible fungi and algae, meat, and tea contain higher levels of associated metals than other selenium-rich agro-food samples. Increasing the consumption of selenium-rich agro-food could make the actual intakes (AIs) of selenium for all population to meet respective recommended daily intakes (RDIs). Benefit-risk assessment results indicated that increasing the consumption of selenium-rich agro-food make AIs of selenium for all populations meet RDIs, chromium intakes for people under 18 years old exceed provisional tolerated daily intake (PTDIs), while arsenic and cadmium intakes are close to PTDIs. The main dietary contributors of selenium, chromium, arsenic and cadmium were meat, edible fungi and algae, rice, and rice, respectively. The study supported the consumption of selenium-rich agro-food for effective selenium supplement, but also emphasized potential risk from associated metals in selenium-rich agro-food, especially chromium.