Amounts Of As Research Articles

Determination of metal(oids) in different traditional flat breads distributed in Isfahan city, Iran: Health risk assessment study by latin hypercube sampling.

This survey was conducted to assess the metal(oids) content in 93 samples of bread, including barbari, lavash, and tafton, using inductive couple plasma/optical emission spectroscopy (ICP-OES) method and atomic absorption spectroscopy (AAS). The amounts of measured element were compared with the permissible limit set for bread by FAO/WHO and Iranian National Standardization Organization (INSO). The limit of detection (LOD) was ranged from 6.6 × 10-5 to 2.1 × 10-2 mg l-1 with recoveries ranged from 92% to 102%. The average concentrations of aluminum (Al), arsenic (As), boron (B), cadmium (Cd), iron (Fe), mercury (Hg), magnesium (Mg), sodium (Na), lead (Pb), and zinc (Zn) in bread were 29.88 ± 8, 0.03 ± 0.004, 12.77 ± 3.70, 0.01 ± 0.006, 34.16 ± 8.95, 0.01 ± 0.008, 346.07 ± 36.08, 3314.81 ± 317.19, 0.24 ± 0.11, and 19.65 ± 4.66 mg Kg-1, respectively. Amounts of As, Cd, Hg, Mg, Pb, and Zn were lower, and those of Al, Fe, and Na were higher than the permissible limits defined by FAO/WHO. The Latin Hyper Cube (LHC) sampling results revealed that children were exposed to higher non-carcinogenic risk and adults were more threatened by carcinogenic risk. It is recommended to control the entrance of metals in bread in the farm-to-fork chain in order to prevent probable future health challenges.

Application of δ-MnO2 and biochar materials in an arsenic-contaminated groundwater.

Two activated biochar materials, peanut char (δ-MnO2 /A-PC) and corn char (δ-MnO2 /A-CC), were used to treat an arsenic solution containing 97.5% As(III) and 2.5% As(V). After reacting with δ-MnO2 /A-PC for 24 h, 18.8% of As(III) and 35.4% of As(V) remained in the solution, revealing that some As(III) was oxidized to As(V) and the other was removed by adsorption. However, δ-MnO2 /A-CC caused the solution to retain 15.6% of As(III) and 41.7% of As(V) under the same conditions, indicating that δ-MnO2 /A-CC had higher oxidation for arsenic species than δ-MnO2 /A-CC. Adsorption capacities for δ-MnO2 /A-PC and δ-MnO2 /A-CC to arsenic were 1.50 and 1.53 mg/g in a solution with 0.5ppm As(III), respectively. After coating with δ-MnO2 , the proportion of mesopore surface areas of δ-MnO2 /A-CC increased from 33.3% to 79.0%, but their mesopore volumes increased from 67.6% to 89.4%. Fourier-transform infrared spectroscopy and X-ray diffraction analyses demonstrated that δ-MnO2 was coated onto the surfaces of the biochars. The 600°C-ACC had a higher specific surface area, 221 m2 /g, than the δ-600°C-APC, 81.5m2 /g; δ-MnO2 /A-CC could attach more Mn (38.2%) than δ-MnO2 /A-PC (27.8%). The elemental analysis revealed that δ-MnO2 /A-PC and δ-MnO2 /A-CC had similar carbon contents of 26.2%. PRACTITIONER POINTS: The δ-MnO2 /biochar adsorbent can oxidize As(III) into As(V) in the groundwater. δ-MnO2 /biochar adsorbed large amounts of As(III) and As(V). Adsorbent that contains more δ-MnO2 has a higher oxidation capacity. The δ-MnO2 /biochar made from corn stalks could combine with more δ-MnO2 .

Toxicological health risk analysis of hazardous trace elements accumulation in the edible fish species of the Black Sea in Türkiye using multivariate statistical and spatial assessment

In the current study, the levels of eleven hazardous trace elements (HTEs) were measured in five different fish species frequently consumed in eleven cities along the Black Sea coast of Türkiye. And also the maximum permissible limits (MPLs) specified by international standards are compared to 11 HTEs levels. In addition, human health risk levels from fish consumption were assessed using multiple approaches. The highest metal concentrations of Fe, Mn, Co, Cr, Ni, Cd and Hg were detected in the fish sampled from Samsun city. It was determined that Cu, Zn, Pb and As metal concentrations were the highest in fish sampled from Düzce city. In the demersal Mullus barbatus (MB), the highest quantities of As, Cr, Mn, Fe, Co, Ni, Hg, and Pb were discovered. The highest concentrations of Zn and Cd were found in Engraulis encrasicolus (EE), which is a topminnow fish. The highest concentrations of Cu were found in Sarda sarda (SS), which is a topminnow fish. For all HTEs, the metal hazard index (MPI) and target hazard quotients (THQ) from metal intake by ingesting fish species were less than 1, indicating no risk from consumption. All investigated fish species were acceptable (10-4 to 10-6) in terms of carcinogenic risks (CR) from exposure to inorganic arsenic (iAs). Additionally, because the hazard index (HI) is less than 1, it has been determined that consuming certain fish species will not pose a risk to public health. The predicted daily intakes of HTEs in each fish species were far lower than their corresponding acceptable daily intakes, indicating that consuming fish would not put consumers at risk for health problems from daily intakes of HTEs. In addition, the multivariate statistical analysis justified that HTEs were from anthropogenic and lithogenic origin.

Phylogenetic analysis and characterization of arsenic (As) transforming bacterial marker proteins following isolation of As-tolerant indigenous bacteria.

Marker proteins play a significant role in bacterial arsenic (As) transformation. Phylogenetic analysis and three-dimensional (3D) characteristics of As transforming bacterial marker proteins guide the evolutionary origin and As transforming potential of the species. Indeed, As-tolerant bacteria also show a significant level of As transformation. Hence, characterization of As transforming bacterial marker proteins, isolation of As transforming bacteria, and proper integration of the findings may guide to elucidate how bacteria transform As. Therefore, phylogenetic analysis and 3D characterization of As transforming bacterial marker protein following isolation of potential indigenous As-tolerant indigenous bacteria were done to explore the mechanism of bacterial As transformation. Phylogenetic analysis of ten As transforming marker proteins (arsA, arsB, arsC, arsD, arsR, aioA, arrA, aioB,acr1, andacr3) in 20 potential bacterial genomes (except19 for the acr3) were studied. Some bacterial genomes featured up to five marker proteins, and therefore, 3D characteristics of the marker proteins were analyzed in those genomes having three-to-five marker proteins. In phylogeny, species in close clades represent their phylogenetic resemblances and may have similar functions. P. aeruginosa, E. coli, and K. pneumonia were found to be more effective due to having the highest number (five) of marker proteins. In 3D protein modeling, most of the marker proteins were found to be active. Among 19 indigenous bacterial isolates, multiple isolates showed tolerance up to 50mM As(III) and 250mM As(V), which may potentially transform a significant quantities of As. Hence, integration of the results of phylogenetic analysis, 3D protein characteristics, and As tolerance in the bacterial isolates could guide to explore the mechanism of how bacteria transform As at cellular and molecular levels.

Influence of irrigation methods on arsenic speciation in rice grain

Although the bioaccumulation of arsenic (As) in rice grains is a global health issue, its speciation is not less worrying. Despite the ascertained effectiveness of the intermittent irrigation methods in minimizing the amount of total As in rice, knowledge of its influence on the As speciation has been insufficient so far. Hence, this contribution was aimed to measure the concentrations of As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) in grains from twenty-six different rice genotypes irrigated either with continuous flooding (CF), periodic saturation (SA) or sprinkler irrigation (SP). In CF-irrigated rice, As(III) and DMA prevailed in roughly equal amounts, only As(III) was found in SA-irrigated rice, whereas As(V) was largely predominant on As(III) in SP-irrigated rice. Organoarsenic species were below the limits of detection (LoD) in rice irrigated by intermittent methods. Principal component analysis (PCA) explained the influence of the irrigation method on the total amount of As, its chemical species, and their correlation. Furthermore, PCA showed also significant differences in As speciation as a function of the rice genotype, whereas no differences were found among Indica and Japonica subspecies.

Retention Effect of Heavy Metals in Rivers of a Typical Mountainous City by Cascade Weirs: A Case Study of Liangtan River in Chongqing

Contaminants such as heavy metals in rivers are partially retained in the sediments at the bottom as a result of the altered water regime within the cascade weirs. The associated heavy metals in the sediments can affect surface water quality and ecology for a long period. In May 2020, sediments were collected in a typical mountainous river (Liangtan River) with cascade weirs in the main urban area of Chongqing. The accumulation of sediments in each river section, the content of heavy metals, and other basic physicochemical indicators in the samples were monitored. The results showed that the average ω(As), ω(Cd), ω(Cu), ω(Hg), ω(Ni), and ω(Pb) in the sediments of the main stream of Liangtan River were (4.66±4.78), (0.361±0.256), (32.30±14.38), (0.069±0.039), (33.47±15.37), and (26.34±11.52) mg·kg-1, respectively. A large coefficient of spatial variation regarding the content of heavy metals in the sediments across the sampling sites was observed owing to the uneven spatial distribution of pollution sources and the destruction of river connectivity by cascade weirs. The modified geoaccumulation index (Im) showed that Cd was the most polluted heavy metal element in the sediments. Of the monitored river sections, 12.50% approached or were at moderate pollution levels, and these sections were mainly found in the upstream and downstream reaches of Liangtan River with relatively concentrated construction lands. The potential ecological risk assessment index method (RI) and the sediment quality guideline method (SQGs) showed that, in addition to Cd and Hg with a high pollution level and strong toxicity, Ni in the sediments also posed a potential threat to the ecological safety of surface water due to its high background content in the watershed. The total amounts of As, Cd, Cu, Hg, Ni, and Pb retained in the sediments by cascade weirs were estimated to be 446.10, 47.28, 4997.80, 10.81, 5135.68, and 4048.16 kg, respectively, in which Cd, Ni, and Pb were identified to be the major threats to the ecological safety of surface water over a long period. The upper reaches prior to the weirs with the most retained heavy metals and the easier formation of an anaerobic environment are suggested to be the key areas for investigation of the endogenous release of heavy metals. Source apportionment of heavy metals in river sediments through the combination of principal component analysis and cluster analysis revealed that Cd, Cu, and Pb mainly originated from residential/industrial point source pollution. Hg mainly originated from agricultural non-point source pollution, whereas As and Ni mainly originated from natural soil erosion.

Adsorption and desorption characteristics of arsenic in calcareous soils as a function of time; equilibrium and thermodynamic study.

Irrigation of carbonate-rich agricultural soils with arsenic (As)-contaminated water leads to the accumulation of As in these soils. In this regard, there is an opportunity to adsorb and fix the As in soil and decrease the As transportation to the plants and subsequently the human food chain. So, the present study aimed to investigate the adsorption-desorption characteristics of As in calcareous soils and the potential of As fixation over time. First, to achieve this purpose, 53 soil samples were gathered from the study site and after the laboratory analysis, the soils were categorized into four groups based on their physicochemical properties. Then, four representative samples of these groups were selected, namely soil 1, soil 2, soil 3, and soil 4. Afterward, the As adsorption-desorption was investigated in a lab-scale batch experiment. Next, the effect of age was assessed by incubating the As-adsorbed soils for 60days, and to study the impact of temperature, the adsorption was performed at four temperature levels (10, 20, 30, and 40°C). Finally, the isotherm models were fitted to experimental data, and the amount of loosely and tightly held As was quantified. Results revealed that the As adsorption isotherms were L-type, in which As adsorption increased with the increase of As loading. The double-site Langmuir (DSL) estimated that a limited amount of As was adsorbed on high-energy surfaces and a large amount of As was adsorbed on low-energy surfaces. Desorption results showed that a significant amount of As desorbed immediately; however, the desorption significantly decreased with the increase of age, especially at low equilibrium concentrations. By aging the loosely held As transformed into non-labile forms so that in soils 1, 2, 3, and 4, the fraction of As adsorbed on high-energy surfaces increased from 72.5, 93.2, 63.2, and 123mg/kg to 167, 141, 70.6, and 196mg/kg, respectively, and the fraction of As adsorbed on low-energy surfaces decreased from 397, 256, 202, and 317mg/kg to 182, 238, 173, and 172mg/kg, respectively (after aging for 60days). Aging proved to be a promising solution for decreasing As transport into the human food chain and could be employed for crops with longer irrigation cycles. ΔHad values were positive and varied from 9.26 to 13.0kJ/mol, confirming the endothermic nature of adsorption. ΔGad values were negative and varied from - 18.8 to - 22.8kJ/mol at all temperatures, demonstrating the spontaneous nature of adsorption.

Risk assessment of heavy metals concentration in cereals and legumes sold in the Tamale Aboabo market, Ghana

The greatest risks posed by heavy metals to human health are linked to exposure to hazardous metals, which may be present in staple foods such as cereals and legumes. In this study, the levels of harmful metals and vital minerals like cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), arsenic (As), and copper (As) in certain cereals and legumes sold in Tamale Aboabo Market in the Northern Region of Ghana were evaluated. A total of twenty-one (21) samples were randomly selected, digested, and analyzed using an atomic absorption spectrophotometer. The samples included three each of cowpea, groundnuts, and soybean (AAS). As concentrations varied from 0.017 mg/kg, Cd concentration was undetectable, Cu concentrations ranged from 0.019 to 0.042 mg/kg, and Zn concentrations were low. The levels of As in the legumes and grains were higher than the 0015 mg/kg FAO/WHO guideline limit. According to the study, there is a risk associated with consuming any of the cereal and legume crops offered in the Tamale Aboabo market that contain any amount of As. The use of pesticides, fertilizers, and runoff from other agricultural fields may have contributed to the higher levels in the cereals. The hazard index via ingestion values for both adults and children were found to be less than 1, indicating no need for potential non-carcinogenic concern. Generally, there is no cancer risk with consumption of the cereals and legumes in terms of all the metals investigated.

Sustainable removal of soil arsenic by naturally-formed iron oxides on plastic tubes

Arsenic (As) pollution in paddy fields is a major threat to rice safety. Existing As remediation techniques are costly, require external chemical addition and degrade soil properties. Here, we report the use of plastic tubes as a recyclable tool to precisely extract As from contaminated soils. Following insertion into flooded paddy soils, polyethylene tube walls were covered by thin but massive Fe coatings of 76.9–367 mg Fe m−2 in 2 weeks, which adsorbed significant amounts of As. The formation of tube-wall Fe oxides was driven by local Fe-oxidizing bacteria with oxygen produced by oxygenic phototrophs (e.g., Cyanobacteria) or diffused from air through the tube wall. The tubes with As-bound Fe oxides can be easily separated from soil and then washed and reused. We tested the As removal efficiency in a pot experiment to remove As from ~ 20 cm depth/40 kg soils in a 2-year experiment and achieved an overall removal efficiency of 152 mg As m−2 soil year−1, comparable to phytoremediation with the As hyperaccumulator Pteris vittata. The cost of Fe hooks was estimated at 8325 RMB ha−1 year−1, and the profit of growing rice (around 16080 RMB ha−1 year−1 can be still maintained. The As accumulated in rice tissues was markedly decreased in the treatment (>11.1 %). This work provides a low-cost and sustainable soil remediation method for the targeted removal of As from soils and a useful tool for the study and management of the biogeochemical Fe cycle in paddy soils.

Investigation of metal mobility in gold and silver mine tailings by single-step and sequential extractions

Metal leachate from mine tailings has the potential to release toxic metals into the surrounding environment. A single-step extraction procedure mimicking rainwater and a three-step BCR sequential extraction procedure (acid, reducing and oxidizing conditions) were applied to gold (GMT) and silver (SMT) mine tailings. Major (Al, Ca, Fe, Mg, and Mn) and trace metals were monitored to better understand the mobility and geochemistry of these metals when exposed to various environmental leaching conditions. Rainwater extraction released only small quantities of metals, while the three-step BCR extraction was more effective in mobilizing metals from the tailings. Under the acidic conditions of BCR step 1, Ca, Mg, Cd, Cu, and Mn were released in high concentrations. The dissolution of Fe, Ca, and Mg were dominant along with Pb in step 2 (reducing conditions). In step 3 (oxidizing conditions), Fe was the most dominant species together with Co, Cu, Ni, and Se. A high fraction of Al, Be, Cr, Li, Mo, Sb, Tl, and V remained in the residue. From SMT, larger quantities of As, Ca, Cd, and Zn were released compared to GMT. The BCR extraction could be applied to tailings to predict the potential release of toxic metals from mine wastes; however, excessive amounts of Ca and Fe in the tailings could cause carry-overs and incomplete extraction and carry-overs, resulting in a misinterpretation of results.

Exposure Evaluation of Toxic Trace Elements in Thai Mulberry Leaves and Commercial Tea Infusion Products

Tea infusion is one of the most widely popular beverages. With several medicinal activities, mulberry leaf is listed as a raw material for tea infusion by the Thai Ministry of Public Health. However, long-term consumption may lead to health risk from toxic trace elements accumulated in herbal raw materials. In this research, the potentially toxic metal (including As, Cd, Pb, Ni and Ba) contents were determined in six mulberry reference leaves and nineteen commercial tea infusion products from local harvester (LHG) and non-harvester (non-LHG) groups using ICP-MS. Each sample was analyzed in triplicate. Health risks of toxic metal consumption was evaluated through content mean value, t-test and Pearson correlation at the significance level of 0.05. The relevant aspects of principal component analysis were also discussed. No observed contents of heavy metals in all sample exceeded the limitation of Thai FDA and WHO. Yet, it was notified that quantity of As, Cd, Ni and Ba in commercial products was higher than that of references while there was no difference in Pb content between two groups. Further investigation found that Cd, Ni and Ba contents in samples from LHG were lower than those from non-LHG significantly. On the contrary, higher Pb content was found in sample from LHG than that from non-LHG group. The amount of As was not different in both groups. As the result, awareness of environmental controls in cultivation area and proper production is crucial to reduce health risk of exposure to heavy metals.

Biochar-supported nanoscale zero-valent iron can simultaneously decrease cadmium and arsenic uptake by rice grains in co-contaminated soil

Cadmium (Cd) and Arsenic (As) in rice grains are a primary exposure source for human beings. However, the simultaneous stabilization of Cd and As in soil becomes difficult due to the opposite properties of those. In this study, we investigated the simultaneous effects of biochar-supported nanoscale zero-valent iron (nZVI-BC) and water management on the decrease of Cd and As bioaccumulation in rice grain. Compared to the control, 0.25–1.00% nZVI-BC coupled with alternate wetting and drying (AWD) management simultaneously decreased the bioaccumulation of Cd and As in rice grains by 15.85–69.16% and 23.06–59.45%, respectively. The cancer risk associated with rice consumption effectively reduced by 15.60–52.41% after the application of nZVI-BC, and the lowest cancer risk was detected in 1.00% nZVI-BC under AWD management. Furthermore, rice cultivated under AWD management had a lower total cancer risk than that cultivated under continuous flooded (CF) management with the same amendment of type and dose. The reduction of soil Cd and As availability and the formation of iron plaque dominated the decrease of Cd and As uptake by rice grains. The elevated soil pH was responsible for Cd adsorption, and the dominant mechanism for As immobilization was the formation of complexes. The iron plaque was double-edged, promoting and inhibiting Cd uptake by rice, wherein the inhibition was predominant under aerobic conditions. In addition, iron plaque was a barrier to preventing the As accumulation by rice, a larger amount of As was immobilized on the iron plaque with nZVI-BC treatment. This study sheds new insights on the simultaneous remediation of Cd and As co-contaminated paddy fields.

Effects of Silicic Acid on Leaching Behavior of Arsenic from Spent Calcium-Based Adsorbents with Arsenite

The spent adsorbents that remain after being used to purify As-contaminated water constitute waste containing a large amount of As. These spent adsorbents, after being disposed, are likely to come into contact with silicic acid leached from the soil or cementitious solidification materials. Thus, it is crucial the evaluate the effects of silicic acid on spent adsorbents. In this study, the effects of silicic acid on spent Ca-based (CaO and Ca(OH)2) adsorbents with arsenite were investigated. The As leaching ratio for the spent adsorbents decreased with an increase in the initial concentration of silicic acid in the liquid. Under the tested conditions, the As leaching ratio decreased from 8–9% to less than 0.7% in the presence of silicic acid at an initial Si-normalized concentration of 100 mg/L. The primary mechanism behind the inhibition of As leaching by silicic acid was determined to be re-immobilization via the incorporation of arsenite during the formation of calcium silicates. In the presence of silicic acid, spent Ca-based adsorbents with arsenite had a lower As leaching ratio than those with arsenate. Therefore, spent Ca-based adsorbents with arsenite were found to have a higher environmental stability than those with arsenate.

Assessment and validation of ICP-MS and IC-ICP-MS methods for the determination of total, extracted and speciated arsenic. Application to samples from a soil-rice system at varying the irrigation method

Food is the major route of arsenic (As) intake for humans, and rice is the staple food for more than half of the world's population. Unfortunately, rice bioaccumulates large amounts of As from the paddy field, and the toxicity of this element in the kernel is closely linked to its chemical form. Therefore, it is of the utmost importance to have access to an integrated set of analytical methods, capable of measuring the concentration of As in its various chemical forms in soil and rice. Hence, the principal aim of this study was to assess and validate a group of inductively coupled plasma – mass spectrometry (ICP-MS) and IC-ICP-MS (IC, Ionic Chromatography) methods designed to measure the amount of the total or extracted As and its main chemical species (As(III), As(V), monomethylarsonic acid, MMA, and dimethylarsinic acid, DMA) in flours of rice grain and in soils. Great attention has been given to the assessment and the optimization of extraction methods of As species from these matrices. No appreciable interconversion among As species has been observed using an aqueous solution 1 mol dm−3 of phosphoric acid and 0.5 mol dm−3 of L (+)-ascorbic acid for the extraction from soils, and an aqueous solution 0.2% (w/v) of nitric acid for the extraction from rice flour. Validation has been successfully accomplished in terms of limit of detection, limit of quantification, linearity and accuracy. In addition to many certified reference materials, these methods have been tested on real samples of soils and rice grains of the Aleramo genotype obtained through traditional or intermittent irrigation methods. Data obtained revealed the critical role of the intermittent irrigation methods in determining the nature and the amount of the As chemical species in rice grains as well as in soils. As(V) is the only species found in soil irrigated by sprinkling, while the most toxic As(III) dominates in soil irrigated by continuous flooding. On the other hand, the most abundant species found in continuously flooded Aleramo rice grains are As(III) and – mostly – DMA, whereas As(V), less toxic than As(III), represents 60% of the total inorganic compounds measured in sprinkler-irrigated rice. Lastly, the total amount of As measured in this rice is 3.8% of that measured in rice irrigated by continuous flooding.

Potentially Mobilizable Geogenic As and Sb in an Agricultural Wetland Soil

The mobility of arsenic (As) and antimony (Sb) in soils is controlled by several processes (adsorption/desorption, (co)precipitation/dissolution and oxidation/reduction), depending on various environmental factors that are often convoluted and site-dependent. This study investigated: (i) the content and solid-phase distribution of geogenic As and Sb in a vertical soil profile (0–130 cm) of an agricultural wetland subject into alternating oxic and anoxic conditions induced by periodic waterlogging and (ii) identifies the stability of the As and Sb host phases during soil reduction (laboratory incubation) using a sequential extraction procedure (fractions: loosely and strongly adsorbed, carbonates, easily reducible, reducible, oxidable and residual). The field results showed that, in the deeper, permanently water-saturated soil layers (<60 cm), the amounts of As and Sb were relatively low (As: 8 ± 2 µg·g−1 and Sb: 0.9 ± 0.2 µg·g−1) and related to the Fe content. In the periodically flooded upper soil layers (0–40 cm), the amounts of As and Sb were higher compared to the deeper layers (As: 36 ± 3 µg·g−1 and Sb: 1.14 ± 0.05 µg·g−1). The observed enrichment towards the surface was attributed to the higher content of organic matter (for Sb) and metalloids distribution among the easily reducible fraction (for As). The anoxic laboratory incubation of periodically waterlogged soil showed that, during soil reduction, As is largely mobilized from the easily reducible fraction and undergoes partial readsorption. Unlike As, Sb displayed a higher affinity for more stable soil components (e.g., reducible and residual fractions), which highlights its limited mobility in periodically waterlogged soil compared to As. The potentially mobilizable As and Sb estimated as the sum of the acetate-exchangeable, P-exchangeable, easily reducible and H2O2-organic fractions represent up to 83%, 69% and 53% of the total As and up to 53%, 44% and 54% of the total Sb at 0–20-cm, 40–60-cm and 90–110-cm depths, respectively. Thus, unpolluted soils may act as sources of As and Sb to aquatic environments and therefore have negative consequence on the downstream water quality.

Pollution assessment and sources of dissolved heavy metals in coastal water of a highly urbanized coastal area: The role of groundwater discharge

Heavy metal concentrations and physicochemical parameters in coastal waters were measured to analyze the spatial distribution characteristics, pollution degrees, and sources of heavy metals in the heavily urbanized Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in China. Heavy metal concentrations in the eastern GBA were higher than those in the west, and the levels of Pb and Zn in seawater were higher than those in groundwater and river water. Both the pollution factors and comprehensive water quality index demonstrated that seawater was not contaminated with As, Cd, Cr, and Ni, whereas low to considerable levels of contamination of Pb and Zn were observed in the central and eastern sections of the GBA. Multiple statistical analyses suggested that the Pb and Zn contaminations in seawater were probably derived from atmospheric deposition and human activities, and the excess amounts of As, Cd, Cu, Ni, and Zn in groundwater were attributed to anthropogenic activities. The heavy metal fluxes from submarine groundwater discharge (SGD) were comparable to, or even greater than, those from local rivers. Therefore, SGD is a significant invisible contributor of heavy metals into the coastal ocean that has often been overlooked in comparison to other visible pollution sources. This study suggests that SGD should be considered in the assessment of heavy metal pollution and future water quality management protocols in marine ecosystems.

Blood and Stool Arsenic Levels Are Decisive for Diagnosing Children's Functional Gastrointestinal Disease (FGD).

Pediatric gastroenteritis is a potentially fatal disease that accounts for 10% of childhood deaths. The main risk is environmental factors and nutrition. Arsenic (As) is commonly found in the earth's crust. As is an essential element that can form many organic compounds. In children, it causes diarrhea, gums, tongue lesions, diabetes, conjunctivitis, ocular opacity, and impaired immune response. It also causes low growth, mental retardation, and neurological problems. It is also known as the cause of many cancers that originate at an early age. Regionally, there is an iron and steel industry for almost a century. According to the Rome IV criteria, the blood and stools of 50 children aged 6-18years, male and female, living in our province with functional gastrointestinal disease (FGD), were screened for As, and compared with the Healthy group (control) of 30 children. The results were evaluated with the Mann-Whitney Rank Sum Test. When blood and stool As values in males were compared with control samples, a high level of significance (p = 0.001) was found between both blood and stool As values in sick males and the control group (p < 0.005). In females, blood and stool As median values were also highly significant when compared with the control group (p = 0.001). According to these data, when the sick children (children with male and female gender) are compared with the healthy ones, the difference is highly significant (p < 0.005). High blood As levels in children indicate environmental pollution. It can be said that blood As levels are high as a result of food, water, and inhaler exposure. The presence of a high level of significant difference in stool means that the amount of As is high in the foods consumed daily. High levels of As are in blood and stools; It was evaluated that FGD could be the cause of nausea, diarrhea, vomiting, and colic. The increase in blood and stool As values due to environmental pollution is an important reason for FGD. For diseases of uncertain cause (such as FGD) resulting from chronic As exposure, blood and especially stool As values are more significant than urinary As levels. In conclusion, As a diagnostic criterion, it was concluded that blood and stool As values are an important marker in children with functional abdominal pain with other metals.

Behaviour of Fe, Mg and Ca in acid mine drainage and experimental solutions in the presence of Aspergillus niger species isolated from various environment

This article analyzes the ability of micromycetes to accumulate Fe, Mg and Ca from acid mine drainage (AMD) at the locality Smolník. Four strains of the Aspergillus niger (An) species originating from various types of environment were used in the experiments: the An-G strain (the locality of Gabčíkovo, Eutric Fluvisol), the An-P strain (the locality of Pezinok-Kolársky vrch, mining region with elevated amounts of As and Sb), the An-N strain (the locality of Nováky, mining region with elevated amounts of As and S), the An-Š strain (Banská ŠtiavnicaŠobov, the locality impacted by an acid sulphate weathering and extremely low pH). In the most cases the accumulation of Mg was the highest in comparison to accumulation of Fe. Accumulation of Ca was very low. Among the tested microfungi, the highest accumulation was noted by the strain An-N 55 % of Mg and by the strain An-Š 54 % of Fe from the model solution of the elements (Fe [1.67 mg/L], Mg [2.35 mg/L] and Ca [1.14 mg/L]).

Vegetables contamination by heavy metals and associated health risk to the population in Koka area of central Ethiopia.

Contaminated soil and vegetables have continued to instigate threat to human health globally and specially in developing countries. This study was aimed to determine concentrations of certain heavy metals in soil and vegetables (cabbage and tomato) from Koka area of central Ethiopia using Inductively Coupled Plasma Optical Emission Spectrophotometer (ICP-OES). The amounts of As, Pb, Cd, Zn, Cu, Hg and Co detected in soil samples were found to surpass the reference values for agricultural soil. Similarly, the concentrations of As, Pb, Cd, Cr and Hg obtained in both tomato and cabbage samples have exceeded the recommended values with the mean levels generally ranging from 0.93-6.76, 1.80-7.26, 0.33-1.03, 0.86-5.16 and 3.23-4.36 mg/kg dry weight, respectively. The result obtained have signified that leafy vegetable has hoarded heavy metals more than non-leafy vegetable. The total hazard quote for As and Hg from tomato ingestion and for As, Hg and Co from cabbage ingestion were greater than unity, signifying potential health hazard to the public. The health index (HI) owing to tomato and cabbage ingesting were 5.44 and 14.21, respectively, signifying likely adversative health implication to the population from the ingestion of the vegetables. The Total Cancer Risk (TCR) analysis have uncovered the possible cancer hazard persuaded by Cd, Hg, As and Ni from the ingestion of both vegetables. From the outcomes this study, it can be concluded that the soil and vegetables from Koka areas are possibly contaminated with toxic metals and hence demand strict monitoring to safeguard the public around the study area and beyond.

Green magnesium oxide nanoparticles-based modulation of cellular oxidative repair mechanisms to reduce arsenic uptake and translocation in rice (Oryza sativa L.) plants

Arsenic (As) accumulation catastrophically disturbs the stability of agricultural systems and human health. Rice easily accumulates a high amount of As from agriculture fields as compare with other cereal crops. Hence, innovative soil remediation methods are needed to deal with the detrimental effects of As on human health causing food security challenges. Here, we report the green synthesis and characterization of magnesium oxide nanoparticles (MgO-NPs) from a native Enterobacter sp. strain RTN2, which was genetically identified through 16S rRNA gene sequence analysis. The biosynthesis of MgO-NPs in reaction mixture was confirmed by UV–vis spectral analysis. X-ray diffraction (XRD) and fourier transform-infrared spectroscopy (FTIR) analysis showed the crystalline nature and surface properties of MgO-NPs, respectively. Moreover, electron microscopy (SEM-EDS, and TEM) imaging confirmed the synthesis of spherical shape of MgO-NPs with variable NPs sizes ranging from 38 to 57 nm. The results revealed that application of MgO-NPs (200 mg kg−1) in As contaminated soil significantly increased the plant biomass, antioxidant enzymatic contents, and decreased reactive oxygen species and acropetal As translocation as compared with control treatment. The study concluded that biogenic MgO-NPs could be used to formulate a potent nanofertilizer for sustainable rice production in metal contaminated soils.